Sample records for raman lidar measurements

  1. Raman lidar and MPL Measurements during ALIVE

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection Radiation ProtectionRaising funds for a cure Raising2 Raman

  2. Raman Lidar Receives Improvements

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection Radiation ProtectionRaising funds for a cure Raising2 Raman Lidar

  3. Raman lidar/AERI PBL Height Product

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Ferrare, Richard

    Planetary Boundary Layer (PBL) heights have been computed using potential temperature profiles derived from Raman lidar and AERI measurements. Raman lidar measurements of the rotational Raman scattering from nitrogen and oxygen are used to derive vertical profiles of potential temperature. AERI measurements of downwelling radiance are used in a physical retrieval approach (Smith et al. 1999, Feltz et al. 1998) to derive profiles of temperature and water vapor. The Raman lidar and AERI potential temperature profiles are merged to create a single potential temperature profile for computing PBL heights. PBL heights were derived from these merged potential temperature profiles using a modified Heffter (1980) technique that was tailored to the SGP site (Della Monache et al., 2004). PBL heights were computed on an hourly basis for the period January 1, 2009 through December 31, 2011. These heights are provided as meters above ground level.

  4. Analysis and Calibration of CRF Raman Lidar Cloud Liquid Water Measurements

    SciTech Connect (OSTI)

    Turner, D.D.

    2007-10-31T23:59:59.000Z

    The Atmospheric Radiation Measurement (ARM) Raman lidar (RL), located at the Southern Great Plains (SGP) Climate Research Facility (CRF), is a unique state-of-the-art active remote sensor that is able to measure profiles of water vapor, aerosol, and cloud properties at high temporal and vertical resolution throughout the diurnal cycle. In October 2005, the capability of the RL was extended by the addition of a new detection channel that is sensitive to the Raman scattering of liquid water. This new channel permits the system, in theory, to measure profiles of liquid water content (LWC) by the RL. To our knowledge, the ARM RL is the only operation lidar with this capability. The liquid water Raman backscattering cross-section is a relatively weak and spectrally broad feature, relative to the water vapor Raman backscatter signal. The wide bandpass required to achieve reasonable signal-to-noise in the liquid water channel essentially eliminates the ability to measure LWC profiles during the daytime in the presence of large solar background, and thus all LWC observations are nighttime only. Additionally, the wide bandpass increases the probability that other undesirable signals, such as fluorescence from aerosols, may contaminate the observation. The liquid water Raman cross-section has a small amount of overlap with the water vapor Raman cross-section, and thus there will be a small amount of ‘cross-talk’ between the two signals, with water vapor contributing a small amount of signal to the LWC observation. And finally, there is significant uncertainty in the actual strength of the liquid water Raman cross-section in the literature. The calibrated LWC profiles, together with the coincident cloud backscatter observations also made by the RL, can be used to derive profiles of cloud droplet effective radius. By combining these profiles of effective radius in the lower portion of the cloud with the aerosol extinction measurements made below the cloud by the RL, the first aerosol indirect effect can be investigated using a single instrument, thereby reducing the uncertainty associated with aligning the different sampling periods and fields of view of multiple instruments. We have applied a “first principles” calibration to the LWC profiles. This approach requires that the relative differences in optical efficiency between the water vapor and liquid water channels be known; this relative difference is easily computed using the efficiency values of the beam splitters and interference filters in the lidar that were provided by the vendors of these components. The first principles approach then transfers the calibration from the water vapor mixing ratio to the LWC using the difference in the optical efficiency and an interpolated value of the liquid water Raman cross section from the literature, and the better established water vapor Raman cross section. After accounting for all known error sources, the vertical integral of LWC was compared against a similar value retrieved from a co-located ground-based infrared radiometer. The RL and infrared radiometer have significantly different fields of view; thus to compare the two sensors the data were averaged to 5 min intervals where only cloudy samples were included in the average of each. While there is fair scatter in the data (r=0.47), there is also a clear indication of a positive correlation between the infrared and the RL values. The value of the slope of the regression is 0.49, which indicates a tendency of the RL measurements to underestimate the total liquid amount with respect to the infrared retrieval. Research continues to investigate the source of the bias, but the most likely candidate is the large uncertainty in the liquid water Raman cross-section as there have been no direct measurements made of this parameter at the lidar’s laser wavelength of 355 nm. The calibrated LWC profile was then used together with the cloud backscatter coefficient profile from the RL to derive profiles of cloud droplet effective radius and cloud droplet number density. These profiles o

  5. Comments on ''Accuracy of Raman lidar water vapor calibration and its applicability to long-term measurements''

    SciTech Connect (OSTI)

    Whiteman, David N.; Venable, Demetrius; Landulfo, Eduardo

    2011-05-20T23:59:59.000Z

    In a recent publication, Leblanc and McDermid [Appl. Opt., 47, 5592 (2008)]APOPAI0003-693510.1364/AO.47.005592 proposed a hybrid calibration technique for Raman water vapor lidar involving a tungsten lamp and radiosondes. Measurements made with the lidar telescope viewing the calibration lamp were used to stabilize the lidar calibration determined by comparison with radiosonde. The technique provided a significantly more stable calibration constant than radiosondes used alone. The technique involves the use of a calibration lamp in a fixed position in front of the lidar receiver aperture. We examine this configuration and find that such a configuration likely does not properly sample the full lidar system optical efficiency. While the technique is a useful addition to the use of radiosondes alone for lidar calibration, it is important to understand the scenarios under which it will not provide an accurate quantification of system optical efficiency changes. We offer examples of these scenarios. Scanning of the full telescope aperture with the calibration lamp can circumvent most of these limitations. Based on the work done to date, it seems likely that the use of multiple calibration lamps in different fixed positions in front of the telescope may provide sufficient redundancy for long-term calibration needs. Further full-aperture scanning experiments, performed over an extended period of time, are needed to determine a ''best practice'' for the use of multiple calibration lamps in the hybrid technique.

  6. Raman Lidar Profiles–Temperature (RLPROFTEMP) Value-Added Product

    SciTech Connect (OSTI)

    Newsom, RK; Sivaraman, C; McFarlane, SA

    2012-10-31T23:59:59.000Z

    The purpose of this document is to describe the Raman Lidar Profiles–Temperature (RLPROFTEMP) value-added product (VAP) and the procedures used to derive atmospheric temperature profiles from the raw RL measurements. Sections 2 and 4 describe the input and output variables, respectively. Section 3 discusses the theory behind the measurement and the details of the algorithm, including calibration and overlap correction.

  7. ARM: 10-second Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Sivaraman, Chitra; Flynn, Connor

    10-second Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

  8. ARM: 2-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Sivaraman, Chitra; Flynn, Connor

    2-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

  9. ARM: 10-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Newsom, Rob; Goldsmith, John

    10-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

  10. ARM: 1-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Sivaraman, Chitra; Flynn, Connor

    1-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

  11. ARM: 1-minute Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Sivaraman, Chitra; Flynn, Connor

    1-minute Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm

  12. ARM: 10-minute Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Newsom, Rob; Goldsmith, John

    10-minute Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm

  13. ARM: 10-minute TEMPORARY Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Sivaraman, Chitra; Flynn, Connor

    10-minute TEMPORARY Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm

  14. ARM: 10-minute TEMPORARY Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Sivaraman, Chitra; Flynn, Connor

    10-minute TEMPORARY Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

  15. ARM: 10-minute Raman Lidar: aerosol depolarization profiles and single layer cloud optical depths from first Turner algorithm

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Newsom, Rob; Goldsmith, John

    10-minute Raman Lidar: aerosol depolarization profiles and single layer cloud optical depths from first Turner algorithm

  16. PROBING NEAR-SURFACE ATMOSPHERIC TURBULENCE WITH LIDAR MEASUREMENTS AND HIGH-RESOLUTION HYDRODYNAMIC MODELS

    SciTech Connect (OSTI)

    J. KAO; D. COOPER; ET AL

    2000-11-01T23:59:59.000Z

    As lidar technology is able to provide fast data collection at a resolution of meters in an atmospheric volume, it is imperative to promote a modeling counterpart of the lidar capability. This paper describes an integrated capability based on data from a scanning water vapor lidar and a high-resolution hydrodynamic model (HIGRAD) equipped with a visualization routine (VIEWER) that simulates the lidar scanning. The purpose is to better understand the spatial and temporal representativeness of the lidar measurements and, in turn, to extend their utility in studying turbulence fields in the atmospheric boundary layer. Raman lidar water vapor data collected over the Pacific warm pool and the simulations with the HIGRAD code are used for identifying the underlying physics and potential aliasing effects of spatially resolved lidar measurements. This capability also helps improve the trade-off between spatial-temporal resolution and coverage of the lidar measurements.

  17. Turn-key Raman lidar for profiling atmospheric water vapor, clouds, and aerosols at the US Southern Great Plains Climate Study Site

    SciTech Connect (OSTI)

    Goldsmith, J.E.M.; Blair, F.H.; Bisson, S.E.

    1997-12-31T23:59:59.000Z

    There are clearly identified scientific requirements for continuous profiling of atmospheric water vapor at the Department of Energy, Atmospheric Radiation Measurement program, Southern Great Plains CART (Cloud and Radiation Testbed) site in northern Oklahoma. Research conducted at several laboratories has demonstrated the suitability of Raman lidar for providing measurements that are an excellent match to those requirements. We have developed and installed a ruggedized Raman lidar system that resides permanently at the CART site, and that is computer automated to eliminate the requirements for operator interaction. In addition to the design goal of profiling water vapor through most of the troposphere during nighttime and through the boundary layer during daytime, the lidar provides quantitative characterizations of aerosols and clouds, including depolarization measurements for particle phase studies.

  18. NO2 lidar profile measurements for satellite interpretation and validation

    E-Print Network [OSTI]

    Dirksen, Ruud

    NO2 lidar profile measurements for satellite interpretation and validation H. Volten,1 E. J matter. We describe a novel instrument, the RIVM NO2 mobile lidar, to measure tropospheric NO2 profiles collection of lidar NO2 profiles, coinciding with OMI and SCIAMACHY overpasses. On clear days and early

  19. LIDAR Wind Speed Measurements of Evolving Wind Fields

    SciTech Connect (OSTI)

    Simley, E.; Pao, L. Y.

    2012-07-01T23:59:59.000Z

    Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed Taylor's frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations to create a more realistic measurement model. A simple model of wind evolution is applied to a frozen wind field used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements are also evaluated with a large eddy simulation of a stable boundary layer provided by the National Center for Atmospheric Research. Simulation results show the combined effects of LIDAR errors and wind evolution for realistic turbine-mounted LIDAR measurement scenarios.

  20. Ris-R-Report LIDAR Wind Speed Measurements from a

    E-Print Network [OSTI]

    the approaching wind fields from this vantage point. Time series of wind speed measurements from the lidar with 50: Time series of the yaw misalignment 67 #12;4 Risø-R-1741(EN) Preface Mikael Rasmussen and Per Hansen is acknowledged for safety supervision of the operation of the NM80 research turbine. The Spin

  1. The effect of specular reflection on spaceborne lidar measurements of ice

    E-Print Network [OSTI]

    Hogan, Robin

    Chapter 2 The effect of specular reflection on spaceborne lidar measurements of ice clouds Summary increase in extinction, it can make interpretation of the lidar echo in terms of cloud radiative properties stage which have among their primary aims the global measurement of ice clouds. The NASA Calipso lidar

  2. Assessment and Optimization of Lidar Measurement Availability for Wind Turbine Control: Preprint

    SciTech Connect (OSTI)

    Davoust, S.; Jehu, A.; Bouillet, M.; Bardon, M.; Vercherin, B.; Scholbrock, A.; Fleming, P.; Wright, A.

    2014-05-01T23:59:59.000Z

    Turbine-mounted lidars provide preview measurements of the incoming wind field. By reducing loads on critical components and increasing the potential power extracted from the wind, the performance of wind turbine controllers can be improved [2]. As a result, integrating a light detection and ranging (lidar) system has the potential to lower the cost of wind energy. This paper presents an evaluation of turbine-mounted lidar availability. Availability is a metric which measures the proportion of time the lidar is producing controller-usable data, and is essential when a wind turbine controller relies on a lidar. To accomplish this, researchers from Avent Lidar Technology and the National Renewable Energy Laboratory first assessed and modeled the effect of extreme atmospheric events. This shows how a multirange lidar delivers measurements for a wide variety of conditions. Second, by using a theoretical approach and conducting an analysis of field feedback, we investigated the effects of the lidar setup on the wind turbine. This helps determine the optimal lidar mounting position at the back of the nacelle, and establishes a relationship between availability, turbine rpm, and lidar sampling time. Lastly, we considered the role of the wind field reconstruction strategies and the turbine controller on the definition and performance of a lidar's measurement availability.

  3. SciTech Connect: Field Test Results from Lidar Measured Yaw Control...

    Office of Scientific and Technical Information (OSTI)

    Conference: Field Test Results from Lidar Measured Yaw Control for Improved Yaw Alignment with the NREL Controls Advanced Research Turbine: Preprint Citation Details In-Document...

  4. Assessment and Optimization of Lidar Measurement Availability for Wind Turbine Control (Poster)

    SciTech Connect (OSTI)

    Scholbrock, F. A.; Fleming, P.; Wright, A.; Davoust, S.; Jehu, A.; Bouillet, M.; Bardon M.; Vercherin, B.

    2014-02-01T23:59:59.000Z

    Integrating Lidar to improve wind turbine controls is a potential breakthrough for reducing the cost of wind energy. By providing undisturbed wind measurements up to 400m in front of the rotor, Lidar may provide an accurate update of the turbine inflow with a preview time of several seconds. Focusing on loads, several studies have evaluated potential reductions using integrated Lidar, either by simulation or full scale field testing.

  5. A new cloud and aerosol layer detection method based on micropulse lidar measurements

    E-Print Network [OSTI]

    Li, Zhanqing

    A new cloud and aerosol layer detection method based on micropulse lidar measurements Chuanfeng algorithm to detect aerosols and clouds based on micropulse lidar measurements. A semidiscretization is then introduced. Combined with empirical threshold values, we determine if the signal waves indicate clouds

  6. Complex-optical-field lidar system for range and vector velocity measurement

    E-Print Network [OSTI]

    Gao, Shuang; Sullivan, Maurice O.; Hui, Rongqing

    2012-11-01T23:59:59.000Z

    Complex-optical-field lidar system for range and vector velocity measurement Shuang Gao,1,2 Maurice O’Sullivan,3 and Rongqing Hui2,* 1Department of Electronic Engineering and Information Science, University of Science and Technology of China... lidar system based on the measurement of complex optical field is demonstrated for the first time. An electro-optic in- phase/quadrature (I/Q) modulator is used in the lidar transmitter to realize carrier-suppressed complex optical field modulation...

  7. High Spectral Resolution Infrared and Raman Lidar Observations for the ARM Program: Clear and Cloudy Sky Applications

    SciTech Connect (OSTI)

    Henry Revercomb, David Tobin, Robert Knuteson, Lori Borg, Leslie Moy

    2009-06-17T23:59:59.000Z

    This grant began with the development of the Atmospheric Emitted Radiance Interferometer (AERI) for ARM. The AERI has provided highly accurate and reliable observations of downwelling spectral radiance (Knuteson et al. 2004a, 2004b) for application to radiative transfer, remote sensing of boundary layer temperature and water vapor, and cloud characterization. One of the major contributions of the ARM program has been its success in improving radiation calculation capabilities for models and remote sensing that evolved from the multi-year, clear-sky spectral radiance comparisons between AERI radiances and line-by-line calculations (Turner et al. 2004). This effort also spurred us to play a central role in improving the accuracy of water vapor measurements, again helping ARM lead the way in the community (Turner et al. 2003a, Revercomb et al. 2003). In order to add high-altitude downlooking AERI-like observations over the ARM sites, we began the development of an airborne AERI instrument that has become known as the Scanning High-resolution Interferometer Sounder (Scanning-HIS). This instrument has become an integral part of the ARM Unmanned Aerospace Vehicle (ARM-UAV) program. It provides both a cross-track mapping view of the earth and an uplooking view from the 12-15 km altitude of the Scaled Composites Proteus aircraft when flown over the ARM sites for IOPs. It has successfully participated in the first two legs of the “grand tour” of the ARM sites (SGP and NSA), resulting in a very good comparison with AIRS observations in 2002 and in an especially interesting data set from the arctic during the Mixed-Phase Cloud Experiment (M-PACE) in 2004. More specifically, our major achievements for ARM include 1. Development of the Atmospheric Emitted Radiance Interferometer (AERI) to function like a satellite on the ground for ARM, providing a steady stream of accurately calibrated spectral radiances for Science Team clear sky and cloud applications (Knuteson et al. 2004a), 2. Detailed radiometric calibration and characterization of AERI radiances, with uncertainty estimates established from complete error analyses and proven by inter-comparison tests (Knuteson et al. 2004b), 3. AERI data quality assessment and maintenance over the extended time frames needed to support ARM (Dedecker et al., 2005) 4. Key role in the radiative transfer model improvements from the AERI/LBLRTM QME (Turner et al. 2004) and AERI-ER especially from the SHEBA experiment (Tobin et al. 1999), 5. Contributed scientific and programmatic leadership leading to significant water vapor accuracy improvements and uncertainty assessments for the low to mid troposphere (Turner et al. 2003a, Revercomb et al. 2003), 6. Leadership of the ARM assessment of the accuracy of water vapor observations from radiosondes, Raman Lidar and in situ aircraft observations in the upper troposphere and lower stratosphere (Tobin et al. 2002, Ferrare et al. 2004), 7. New techniques for characterizing clouds from AERI (DeSlover et al. 1999, Turner 2003b, Turner et al. 2003b), 8. Initial design and development of the Scanning-HIS aircraft instrument and application to ARM UAV Program missions (Revercomb et al. 2005), and 9. Coordinated efforts leading to the use of ARM observations as a key validation tool for the high resolution Atmospheric IR Sounder on the NASA Aqua platform (Tobin et al. 2005a) 10. Performed ARM site and global clear sky radiative closure studies that shows closure of top-of-atmosphere flux at the level of ~1 W/m2 (Moy et al 2008 and Section 3 of this appendix) 11. Performed studies to characterize SGP site cirrus cloud property retrievals and assess impacts on computed fluxes and heating rate profiles (Borg et al. 2008 and Section 2 of this appendix).

  8. Development of a lidar polarimeter technique of measuring suspended solids in water

    E-Print Network [OSTI]

    Presley, David W

    1980-01-01T23:59:59.000Z

    of depolarization would indicate the relative concentration of scattering particles. The laboratory measurements supported the hypothesis and established the potential of measuri ng suspended solids, turbi dity and transmi ssi vi ty using a lidar polarimeter...

  9. The effect of specular reflection on spaceborne lidar measurements of ice clouds ROBIN J. HOGAN # AND ANTHONY J. ILLINGWORTH

    E-Print Network [OSTI]

    Hogan, Robin

    The effect of specular reflection on spaceborne lidar measurements of ice clouds ROBIN J. HOGAN echo in terms of cloud radiative properties problematic, so is of concern for spaceborne cloud lidar which have among their primary aims the global measurement of ice clouds. The NASA Calipso li­ dar

  10. Master thesis: "Validation of wake-simulation models based on long-range lidar measurements."

    E-Print Network [OSTI]

    Peinke, Joachim

    REpower 6M wind turbines with rotor blades of different designs installed in the Ellhöft/Westre wind farm developed by the wind turbine manufacturer. Work plan 2011 2012 Task 11 12 01 02 03 04 05 06 07 08 09 10 Figure 1: Simulation of lidar measurements in the wake of a wind turbine using a LES generated wind field

  11. Surface-Layer Wind and Turbulence Profiling from LIDAR: Theory and Measurements

    E-Print Network [OSTI]

    Surface-Layer Wind and Turbulence Profiling from LIDAR: Theory and Measurements Régis DANIELIAN (Vestas Wind System) Hans Ejsing JØRGENSEN (Wind Energy Department, Risø. Contact: haej@risoe.dk) Torben MIKKELSEN (Wind Energy Department, Risø. Contact: tomi@risoe.dk) Jacob MANN (Wind Energy Department, Risø

  12. Upstream Measurements of Wind Profiles with Doppler Lidar for Improved Wind Energy Integration

    SciTech Connect (OSTI)

    Rodney Frehlich

    2012-10-30T23:59:59.000Z

    New upstream measurements of wind profiles over the altitude range of wind turbines will be produced using a scanning Doppler lidar. These long range high quality measurements will provide improved wind power forecasts for wind energy integration into the power grid. The main goal of the project is to develop the optimal Doppler lidar operating parameters and data processing algorithms for improved wind energy integration by enhancing the wind power forecasts in the 30 to 60 minute time frame, especially for the large wind power ramps. Currently, there is very little upstream data at large wind farms, especially accurate wind profiles over the full height of the turbine blades. The potential of scanning Doppler lidar will be determined by rigorous computer modeling and evaluation of actual Doppler lidar data from the WindTracer system produced by Lockheed Martin Coherent Technologies, Inc. of Louisville, Colorado. Various data products will be investigated for input into numerical weather prediction models and statistically based nowcasting algorithms. Successful implementation of the proposed research will provide the required information for a full cost benefit analysis of the improved forecasts of wind power for energy integration as well as the added benefit of high quality wind and turbulence information for optimal control of the wind turbines at large wind farms.

  13. Wind velocity measurements using a pulsed LIDAR system: first results

    E-Print Network [OSTI]

    Peinke, Joachim

    . A laser beam of 1.54 µm wavelength takes measurements of the wind speed in beamwise direction. To obtain the three-dimensinal wind vector, the beam is inclined by 30 from vertical direction and measurements 12345 t [s] vh[m/s] Figure 2. Segment of measured time series of the horizontal wind speed magnitude vh

  14. Lidar Measurements of the Vertical Distribution of Aerosol Optical and Physical Properties over Central Asia

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, Boris B.; Sverdlik, Leonid G.; Imashev, Sanjar A.; Solomon, Paul A.; Lantz, Jeffrey; Schauer, James J.; Shafer, Martin M.; Artamonova, Maria S.; Carmichael, Gregory R.

    2013-01-01T23:59:59.000Z

    The vertical structure of aerosol optical and physical properties was measured by Lidar in Eastern Kyrgyzstan, Central Asia, from June 2008 to May 2009. Lidar measurements were supplemented with surface-based measurements of PM2.5and PM10mass and chemical composition in both size fractions. Dust transported into the region is common, being detected 33% of the time. The maximum frequency occurred in the spring of 2009. Dust transported to Central Asia comes from regional sources, for example, Taklimakan desert and Aral Sea basin, and from long-range transport, for example, deserts of Arabia, Northeast Africa, Iran, and Pakistan. Regional sources are characterized by pollutionmore »transport with maximum values of coarse particles within the planetary boundary layer, aerosol optical thickness, extinction coefficient, integral coefficient of aerosol backscatter, and minimum values of the Ångström exponent. Pollution associated with air masses transported over long distances has different characteristics during autumn, winter, and spring. During winter, dust emissions were low resulting in high values of the Ångström exponent (about 0.51) and the fine particle mass fraction (64%). Dust storms were more frequent during spring with an increase in coarse dust particles in comparison to winter. The aerosol vertical profiles can be used to lower uncertainty in estimating radiative forcing.« less

  15. Field Test Results from Lidar Measured Yaw Control for Improved Yaw Alignment with the NREL Controls Advanced Research Turbine: Preprint

    SciTech Connect (OSTI)

    Scholbrock, A.; Fleming, P.; Wright, A.; Slinger, C.; Medley, J.; Harris, M.

    2014-12-01T23:59:59.000Z

    This paper describes field tests of a light detection and ranging (lidar) device placed forward looking on the nacelle of a wind turbine and used as a wind direction measurement to directly control the yaw position of a wind turbine. Conventionally, a wind turbine controls its yaw direction using a nacelle-mounted wind vane. If there is a bias in the measurement from the nacelle-mounted wind vane, a reduction in power production will be observed. This bias could be caused by a number of issues such as: poor calibration, electromagnetic interference, rotor wake, or other effects. With a lidar mounted on the nacelle, a measurement of the wind could be made upstream of the wind turbine where the wind is not being influenced by the rotor's wake or induction zone. Field tests were conducted with the lidar measured yaw system and the nacelle wind vane measured yaw system. Results show that a lidar can be used to effectively measure the yaw error of the wind turbine, and for this experiment, they also showed an improvement in power capture because of reduced yaw misalignment when compared to the nacelle wind vane measured yaw system.

  16. Measuring depth profiles of residual stress with Raman spectroscopy

    SciTech Connect (OSTI)

    Enloe, W.S.; Sparks, R.G.; Paesler, M.A.

    1988-12-01T23:59:59.000Z

    Knowledge of the variation of residual stress is a very important factor in understanding the properties of machined surfaces. The nature of the residual stress can determine a part`s susceptibility to wear deformation, and cracking. Raman spectroscopy is known to be a very useful technique for measuring residual stress in many materials. These measurements are routinely made with a lateral resolution of 1{mu}m and an accuracy of 0.1 kbar. The variation of stress with depth; however, has not received much attention in the past. A novel technique has been developed that allows quantitative measurement of the variation of the residual stress with depth with an accuracy of 10nm in the z direction. Qualitative techniques for determining whether the stress is varying with depth are presented. It is also demonstrated that when the stress is changing over the volume sampled, errors can be introduced if the variation of the stress with depth is ignored. Computer aided data analysis is used to determine the depth dependence of the residual stress.

  17. Chemical concentration measurement in blood serum and urine samples using liquid-core optical fiber Raman

    E-Print Network [OSTI]

    Berger, Andrew J.

    Chemical concentration measurement in blood serum and urine samples using liquid-core optical fiber in clinical blood serum and urine samples using liquid-core optical fiber (LCOF) Raman spectroscopy-core optical fiber (LCOF) geome- try can enhance the collected Raman signal from nonturbid aqueous samples by 1

  18. Comparing Pulsed Doppler LIDAR with SODAR and Direct Measurements for Wind Assessment

    SciTech Connect (OSTI)

    Kelley, N. D.; Jonkman, B. J.; Scott, G. N.; Pichugina, Y. L.

    2007-07-01T23:59:59.000Z

    There is a pressing need for good wind-speed measurements at greater and greater heights to assess the availability of the resource in terms of power production and to identify any frequently occurring atmospheric structural characteristics that may create turbulence that impacts the operational reliability and lifetime of wind turbines and their components. In this paper, we summarize the results of a short study that compares the relative accuracies of wind speeds derived from a high-resolution pulsed Doppler LIDAR operated by the National Oceanic and Atmospheric Administration (NOAA) and a midrange Doppler SODAR with wind speeds measured by four levels of tower-based sonic anemometry up to a height of 116 m.

  19. 3D Temperature Measurement in IC Chips using Confocal Raman Spectroscopy Javad Shabani, Xi Wang, and Ali Shakouri

    E-Print Network [OSTI]

    . The feasibility of using Raman spectroscopy for remote temperature measurement in depth was investigated value where the surface temperature starts to rise due to heating by incident light. #12;Raman

  20. Photo-oxidation of Ge Nanocrystals: Kinetic Measurements by In Situ Raman Spectroscopy

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

    Photo-oxidation of Ge Nanocrystals: Kinetic Measurements byBerkeley, CA, 94720 ABSTRACT Ge nanocrystals are formed inthe Raman spectra of the Ge nanocrystals in-situ. The

  1. Rotational-Vibrational Raman Spectroscopy for Measurements of Thermochemistry in Non-isobaric Environments

    E-Print Network [OSTI]

    Bayeh, Alexander C.

    2010-01-14T23:59:59.000Z

    The present work examines line measurements of pressure, temperature, and density in high speed, non-isobaric flows emanating from an underexpanded jet nozzle. Line images of rotational and vibrational Raman spectra are collected for a 8-mm linear...

  2. Posters Scanning Raman Lidar Measurements of Atmospheric Water Vapor and Aerosols

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible forPortsmouth/Paducah Project Office PressPostdoctoraldecadal observations719711 Posters5

  3. Raman Lidar Measurements of Aerosols and Water Vapor During the May 2003 Aerosol IOP

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection Radiation ProtectionRaising funds for a cure Raising

  4. Rotational and Vibrational Raman Spectroscopy for Thermochemistry Measurements in Supersonic Flames

    E-Print Network [OSTI]

    Bayeh, Alexander C

    2013-05-31T23:59:59.000Z

    the development of new line imaging diagnostics for thermochemistry measurements in high speed flows. A novel combination of vibrational and rotational Raman scattering is used to measure major species densities (O_2, N_2, CH_4, H_2O,CO_2, CO, & H_2...

  5. Rayleigh LIDAR and satellite (HALOE, SABER, CHAMP and COSMIC) measurements of stratosphere-mesosphere temperature over a southern sub-tropical site, Reunion (20.8° S; 55.5° E): climatology and comparison study

    E-Print Network [OSTI]

    Sivakumar, V.; Vishnu Prasanth, P.; Kishore, P.; Bencherif, H.; Keckhut, P.

    2011-01-01T23:59:59.000Z

    climatology of the mid- dle atmosphere from long-termLIDAR measurements at mid- dle and low latitudes, J.Over the southern tropics, mid- dle atmosphere temperature

  6. Horizontal-Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Yelena L.; Banta, Robert M.; Kelley, Neil D.; Jonkman, Bonnie J.; Tucker, Sara C.; Newsom, Rob K.; Brewer, W. A.

    2008-08-01T23:59:59.000Z

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--has been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAA’s High Resolution Doppler Lidar (HRDL), which have been shown to be numerically equivalent to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance ?u2 were computed from HRDL measurements of the line-of-sight (LOS) velocity using a technique described in Banta, et al. (2002). The technique was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. It then describes several series of averaging tests that produced the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal velocity variance ?u2. The results show high correlation (0.71-0.97) of the mean U and average wind speed measured by sodar and in-situ instruments, independent of sampling strategies and averaging procedures. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging techniques.

  7. Light trapping in thin-film solar cells measured by Raman spectroscopy

    SciTech Connect (OSTI)

    Ledinský, M., E-mail: ledinsky@fzu.cz [Laboratory of Nanostructures and Nanomaterials, Institute of Physics, Academy of Sciences of the Czech Republic, v. v. i., Cukrovarnická 10, 162 00 Prague (Czech Republic); Photovoltaics and Thin Film Electronics Laboratory, Institute of Microengineering (IMT), École Polytechnique Fédérale de Lausanne (EPFL), Rue de la Maladière 71b, CH-2000 Neuchâtel (Switzerland); Moulin, E.; Bugnon, G.; Meillaud, F.; Ballif, C. [Photovoltaics and Thin Film Electronics Laboratory, Institute of Microengineering (IMT), École Polytechnique Fédérale de Lausanne (EPFL), Rue de la Maladière 71b, CH-2000 Neuchâtel (Switzerland); Ganzerová, K.; Vetushka, A.; Fejfar, A. [Laboratory of Nanostructures and Nanomaterials, Institute of Physics, Academy of Sciences of the Czech Republic, v. v. i., Cukrovarnická 10, 162 00 Prague (Czech Republic)

    2014-09-15T23:59:59.000Z

    In this study, Raman spectroscopy is used as a tool to determine the light-trapping capability of textured ZnO front electrodes implemented in microcrystalline silicon (?c-Si:H) solar cells. Microcrystalline silicon films deposited on superstrates of various roughnesses are characterized by Raman micro-spectroscopy at excitation wavelengths of 442?nm, 514?nm, 633?nm, and 785?nm, respectively. The way to measure quantitatively and with a high level of reproducibility the Raman intensity is described in details. By varying the superstrate texture and with it the light trapping in the ?c-Si:H absorber layer, we find significant differences in the absolute Raman intensity measured in the near infrared wavelength region (where light trapping is relevant). A good agreement between the absolute Raman intensity and the external quantum efficiency of the ?c-Si:H solar cells is obtained, demonstrating the validity of the introduced method. Applications to thin-film solar cells, in general, and other optoelectronic devices are discussed.

  8. Quantitative concentration measurements of creatinine dissolved in water and urine using Raman

    E-Print Network [OSTI]

    Berger, Andrew J.

    to the lack of suitable materials with refractive indices lower that of water (n 1.33). Recently, howeverQuantitative concentration measurements of creatinine dissolved in water and urine using Raman in water and in urine. At short integration times, where shot noise is most troublesome, the enhanced

  9. Fiber-optic apparatus and method for measurement of luminescence and raman scattering

    DOE Patents [OSTI]

    Myrick, Michael L. (Livermore, CA); Angel, Stanley M. (Livermore, CA)

    1993-01-01T23:59:59.000Z

    A dual fiber forward scattering optrode for Raman spectroscopy with the remote ends of the fibers in opposed, spaced relationship to each other to form a analyte sampling space therebetween and the method of measuring Raman spectra utilizing same. One optical fiber is for sending an exciting signal to the remote sampling space and, at its remote end, has a collimating microlens and an optical filter for filtering out background emissions generated in the fiber. The other optical fiber is for collecting the Raman scattering signal at the remote sampling space and, at its remote end, has a collimating microlens and an optical filter to prevent the exciting signal from the exciting fiber from entering the collection fiber and to thereby prevent the generation of background emissions in the collecting fiber.

  10. Multiscalar line measurements in nonisobaric high-pressure underexpanded supersonic jets using rotational-vibrational raman spectroscopy

    E-Print Network [OSTI]

    Cohen, Benjamin Nathan

    2009-05-15T23:59:59.000Z

    line. In every point, temperature will be measured by examining the Boltzmann decay of the rotational spectrum, while molar fraction will be measured from the vibrational Raman spectrum. The temperature and concentrations will then be combined to obtain...

  11. LIDAR Wind Speed Measurement Analysis and Feed-Forward Blade Pitch Control for Load Mitigation in Wind Turbines: January 2010--January 2011

    SciTech Connect (OSTI)

    Dunne, F.; Simley, E.; Pao, L.Y.

    2011-10-01T23:59:59.000Z

    This report examines the accuracy of measurements that rely on Doppler LIDAR systems to determine their applicability to wind turbine feed-forward control systems and discusses feed-forward control system designs that use preview wind measurements. Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feed-forward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. The first half of this report examines the accuracy of different measurement scenarios that rely on coherent continuous-wave or pulsed Doppler LIDAR systems to determine their applicability to feed-forward control. In particular, the impacts of measurement range and angular offset from the wind direction are studied for various wind conditions. A realistic case involving a scanning LIDAR unit mounted in the spinner of a wind turbine is studied in depth with emphasis on choices for scan radius and preview distance. The effects of turbulence parameters on measurement accuracy are studied as well. Continuous-wave and pulsed LIDAR models based on typical commercially available units were used in the studies present in this report. The second half of this report discusses feed-forward control system designs that use preview wind measurements. Combined feedback/feed-forward blade pitch control is compared to industry standard feedback control when simulated in realistic turbulent above-rated winds. The feed-forward controllers are designed to reduce fatigue loads, increasing turbine lifetime and therefore reducing the cost of energy. Three feed-forward designs are studied: non-causal series expansion, Preview Control, and optimized FIR filter. The input to the feed-forward controller is a measurement of incoming wind speeds that could be provided by LIDAR. Non-causal series expansion and Preview Control methods reduce blade root loads but increase tower bending in simulation results. The optimized FIR filter reduces loads overall, keeps pitch rates low, and maintains rotor speed regulation and power capture, while using imperfect wind measurements provided by the spinning continuous-wave LIDAR model.

  12. An Atmospheric Radiation Measurement Value-Added Product to Retrieve Optically Thin Cloud Visible Optical Depth using Micropulse Lidar

    SciTech Connect (OSTI)

    Lo, C; Comstock, JM; Flynn, C

    2006-10-01T23:59:59.000Z

    The purpose of the Micropulse Lidar (MPL) Cloud Optical Depth (MPLCOD) Value-Added Product (VAP) is to retrieve the visible (short-wave) cloud optical depth for optically thin clouds using MPL. The advantage of using the MPL to derive optical depth is that lidar is able to detect optically thin cloud layers that may not be detected by millimeter cloud radar or radiometric techniques. The disadvantage of using lidar to derive optical depth is that the lidar signal becomes attenuation limited when ? approaches 3 (this value can vary depending on instrument specifications). As a result, the lidar will not detect optically thin clouds if an optically thick cloud obstructs the lidar beam.

  13. Micropulse Lidar (MPL) Handbook

    SciTech Connect (OSTI)

    Mendoza, A; Flynn, C

    2006-05-01T23:59:59.000Z

    The micropulse lidar (MPL) is a ground-based optical remote sensing system designed primarily to determine the altitude of clouds overhead. The physical principle is the same as for radar. Pulses of energy are transmitted into the atmosphere; the energy scattered back to the transceiver is collected and measured as a time-resolved signal. From the time delay between each outgoing transmitted pulse and the backscattered signal, the distance to the scatterer is infered. Besides real-time detection of clouds, post-processing of the lidar return can also characterize the extent and properties of aerosol or other particle-laden regions.

  14. Horizontal Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Y. L.; Banta, R. M.; Kelley, N. D.; Jonkman, B. J.; Tucker, S. C.; Newsom, R. K.; Brewer, W. A.

    2008-08-01T23:59:59.000Z

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--have been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAA's high-resolution Doppler lidar (HRDL), which have been shown to be approximately equal to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance {sigma}2u were computed from HRDL measurements of the line-of-sight (LOS) velocity using a method described by Banta et al., which uses an elevation (vertical slice) scanning technique. The method was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. The results for the mean U and mean wind speed measured by sodar and in situ instruments for all nights of LLLJP show high correlation (0.71-0.97), independent of sampling strategies and averaging procedures, and correlation coefficients consistently >0.9 for four high-wind nights, when the low-level jet speeds exceeded 15 m s{sup -1} at some time during the night. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging parameters. Several series of averaging tests are described, to find the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal-velocity variance {sigma}{sup 2}{sub u}. Because of the nonstationarity of the SBL data, the best results were obtained when the velocity data were first averaged over intervals of 1 min, and then further averaged over 3-15 consecutive 1-min intervals, with best results for the 10- and 15-min averaging periods. For these cases, correlation coefficients exceeded 0.9. As a part of the analysis, Eulerian integral time scales ({tau}) were estimated for the four high-wind nights. Time series of {tau} through each night indicated erratic behavior consistent with the nonstationarity. Histograms of {tau} showed a mode at 4-5 s, but frequent occurrences of larger {tau} values, mostly between 10 and 100 s.

  15. High-pressure behavior of amorphous selenium from ultrasonic measurements and Raman spectroscopy

    SciTech Connect (OSTI)

    He, Z.; Liu, X. R.; Hong, S. M., E-mail: hpswjtu@gmail.com, E-mail: smhong@home.swjtu.edu.cn [Laboratory of High Pressure Physics, Southwest Jiaotong University, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Chengdu 610031 (China); Wang, Z. G. [National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900 (China); Zhu, H. Y. [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Peng, J. P. [School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031 (China)

    2014-07-07T23:59:59.000Z

    The high-pressure behavior of melt-quenched amorphous selenium (a-Se) has been investigated via ultrasonic measurements and Raman scattering at room temperature. The ultrasonic measurements were conducted on a-Se in a multi-anvil apparatus with two different sample assemblies at pressures of up to 4.5 and 4.8?GPa. We discovered that similar kinks occur in the slopes of the pressure dependence characteristics of the travel time and the sound velocity in both shear and longitudinal waves in the 2.0–2.5?GPa range. These kinks are independent of the sample assemblies, indicating an intrinsic transformation of the a-Se. Additionally, we deduced the pressure-volume relationship of a-Se from the sound velocity characteristics using the Birch–Murnaghan equation of state, and the results agreed well with those of previous reports. In situ high-pressure Raman scattering measurements of a-Se were conducted in a diamond anvil cell with an 830?nm excitation line up to a pressure of 4.3?GPa. We found that the characteristic band of a-Se at ?250?cm{sup ?1} experienced a smooth shift to a lower frequency with pressure, but a sharp slope change in the band intensity versus pressure occurred near 2.5?GPa. The results of X-ray diffraction and differential scanning calorimetry measurements indicate that the samples remain in their amorphous states after decompression. Thus, we proposed that the abnormal compression behavior of a-Se in the 2.0–2.5?GPa range can be attributed to pressure-induced local atomic reconfiguration, implying an amorphous-amorphous transition of the elementary selenium.

  16. Self-heating in a GaN based heterostructure field effect transistor: Ultraviolet and visible Raman measurements and simulations

    E-Print Network [OSTI]

    Holtz, Mark

    Self-heating in a GaN based heterostructure field effect transistor: Ultraviolet and visible Raman online 8 December 2006 We report direct self-heating measurements for AlGaN/GaN heterostructure field density can be commensurately high, collisional energy loss from electrons to the crystal leads to self-heating

  17. Thermoelectric and micro-Raman measurements of carrier density and mobility in heavily Si-doped GaN wires

    E-Print Network [OSTI]

    Boyer, Edmond

    Thermoelectric and micro-Raman measurements of carrier density and mobility in heavily Si-doped Ga (Received 19 July 2013; accepted 28 October 2013; published online 11 November 2013) Combined thermoelectric epitaxy (MOVPE). These highly conductive Si-doped GaN wires were studied by means of thermoelectrical

  18. Phonon deformation potentials in wurtzite GaN and ZnO determined by uniaxial pressure dependent Raman measurements

    E-Print Network [OSTI]

    Nabben, Reinhard

    Phonon deformation potentials in wurtzite GaN and ZnO determined by uniaxial pressure dependent deformation potentials in wurtzite GaN and ZnO determined by uniaxial pressure dependent Raman measurements G online 9 February 2011 We report the phonon deformation potentials of wurtzite GaN and ZnO for all zone

  19. Arctic-Winter Climatology and Radiative Effects of Clouds and Aerosols Based on Lidar and Radar Measurements at PEARL

    E-Print Network [OSTI]

    Eloranta, Edwin W.

    Arctic-Winter Climatology and Radiative Effects of Clouds and Aerosols Based on Lidar and Radar Atmospheric Radiative Transfer (SBDART) code. Results on the climatology and radiative effects of clouds, arctic regions are the site of interactions between aerosols, clouds, radiation and precipitations

  20. Using Radar, Lidar, and Radiometer measurements to Classify Cloud Type and Study Middle-Level Cloud Properties

    SciTech Connect (OSTI)

    Wang, Zhien

    2010-06-29T23:59:59.000Z

    The project is mainly focused on the characterization of cloud macrophysical and microphysical properties, especially for mixed-phased clouds and middle level ice clouds by combining radar, lidar, and radiometer measurements available from the ACRF sites. First, an advanced mixed-phase cloud retrieval algorithm will be developed to cover all mixed-phase clouds observed at the ACRF NSA site. The algorithm will be applied to the ACRF NSA observations to generate a long-term arctic mixed-phase cloud product for model validations and arctic mixed-phase cloud processes studies. To improve the representation of arctic mixed-phase clouds in GCMs, an advanced understanding of mixed-phase cloud processes is needed. By combining retrieved mixed-phase cloud microphysical properties with in situ data and large-scale meteorological data, the project aim to better understand the generations of ice crystals in supercooled water clouds, the maintenance mechanisms of the arctic mixed-phase clouds, and their connections with large-scale dynamics. The project will try to develop a new retrieval algorithm to study more complex mixed-phase clouds observed at the ACRF SGP site. Compared with optically thin ice clouds, optically thick middle level ice clouds are less studied because of limited available tools. The project will develop a new two wavelength radar technique for optically thick ice cloud study at SGP site by combining the MMCR with the W-band radar measurements. With this new algorithm, the SGP site will have a better capability to study all ice clouds. Another area of the proposal is to generate long-term cloud type classification product for the multiple ACRF sites. The cloud type classification product will not only facilitates the generation of the integrated cloud product by applying different retrieval algorithms to different types of clouds operationally, but will also support other research to better understand cloud properties and to validate model simulations. The ultimate goal is to improve our cloud classification algorithm into a VAP.

  1. Comments on: ARM Raman Lidar Applications

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i tCollaboration MarchCanadian2016Department

  2. Comments on: ARM Raman Lidar Development

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i tCollaboration MarchCanadian2016Department

  3. Sandia Energy - ARM Raman Lidar Applications

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Scienceand Requirements RecentlyElectronicResourcesjobsJulyCatalysts and2015 VIIIApplications Home

  4. Sandia Energy - ARM Raman Lidar Development

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Scienceand Requirements RecentlyElectronicResourcesjobsJulyCatalysts and2015 VIIIApplications

  5. ARM - Measurement - Lidar polarization

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDC documentationBarrow,ice

  6. The Ability of MM5 to Simulate Ice Clouds: Systematic Comparison between Simulated and Measured Fluxes and Lidar/Radar Profiles at SIRTA Atmospheric Observatory

    SciTech Connect (OSTI)

    Chiriaco, M.; Vautard, R.; Chepfer, H.; Haeffelin, M.; Wanherdrick, Y.; Morille, Y.; Protat, A.; Dudhia, J.

    2005-03-18T23:59:59.000Z

    Ice clouds play a major role in the radiative energy budget of the Earth-atmosphere system (Liou 1986). Their radiative effect is governed primarily by the equilibrium between their albedo and greenhouse effects. Both macrophysical and microphysical properties of ice clouds regulate this equilibrium. For quantifying the effect of these clouds onto climate and weather systems, they must be properly characterized in atmospheric models. In this paper we use remote-sensing measurements from the SIRTA ground based atmospheric observatory (Site Instrumental de Recherche par Teledetection Atmospherique, http://sirta.lmd.polytechnique.fr). Lidar and radar observations taken over 18 months are used, in order to gain statistical confidence in the model evaluation. Along this period of time, 62 days are selected for study because they contain parts of ice clouds. We use the ''model to observations'' approach by simulating lidar and radar signals from MM5 outputs. Other more classical variables such as shortwave and longwave radiative fluxes are also used. Four microphysical schemes, among which that proposed by Reisner et al. (1998) with original or modified parameterizations of particle terminal fall velocities (Zurovac-Jevtic and Zhang 2003, Heymsfield and Donner 1990), and the simplified Dudhia (1989) scheme are evaluated in this study.

  7. Coded Aperture Raman Spectroscopy for Quantitative Measurements of Ethanol in a Tissue Phantom

    E-Print Network [OSTI]

    Pitsianis, Nikos P.

    - mard transform spectroscopy'' (HTS).9 Initially, HTS systems were designed to use multiplexing tissue phantom. With 60 mW of excitation power at 808 nm, leave-one-out and blind cross spectroscopy; Multiplexing; Chemometrics. INTRODUCTION Raman spectroscopy is a powerful diagnostic tool

  8. Doppler Lidar (DL) Handbook

    SciTech Connect (OSTI)

    Newsom, RK

    2012-02-13T23:59:59.000Z

    The Doppler lidar (DL) is an active remote sensing instrument that provides range- and time-resolved measurements of radial velocity and attenuated backscatter. The principle of operation is similar to radar in that pulses of energy are transmitted into the atmosphere; the energy scattered back to the transceiver is collected and measured as a time-resolved signal. From the time delay between each outgoing transmitted pulse and the backscattered signal, the distance to the scatterer is inferred. The radial or line-of-sight velocity of the scatterers is determined from the Doppler frequency shift of the backscattered radiation. The DL uses a heterodyne detection technique in which the return signal is mixed with a reference laser beam (i.e., local oscillator) of known frequency. An onboard signal processing computer then determines the Doppler frequency shift from the spectra of the heterodyne signal. The energy content of the Doppler spectra can also be used to determine attenuated backscatter.

  9. Deriving a Framework for Estimating Individual Tree Measurements with Lidar for Use in the TAMBEETLE Southern Pine Beetle Infestation Growth Model

    E-Print Network [OSTI]

    Stukey, Jared D.

    2011-02-22T23:59:59.000Z

    The overall goal of this study was to develop a framework for using airborne lidar to derive inputs for the SPB infestation growth model TAMBEETLE. The specific objectives were (1) to estimate individual tree characteristics of XY location...

  10. LIDAR, Point Clouds, and their Archaeological Applications

    SciTech Connect (OSTI)

    White, Devin A [ORNL

    2013-01-01T23:59:59.000Z

    It is common in contemporary archaeological literature, in papers at archaeological conferences, and in grant proposals to see heritage professionals use the term LIDAR to refer to high spatial resolution digital elevation models and the technology used to produce them. The goal of this chapter is to break that association and introduce archaeologists to the world of point clouds, in which LIDAR is only one member of a larger family of techniques to obtain, visualize, and analyze three-dimensional measurements of archaeological features. After describing how point clouds are constructed, there is a brief discussion on the currently available software and analytical techniques designed to make sense of them.

  11. Inelastic neutron and low-frequency Raman scattering in a niobium-phosphate glass for Raman gain applications

    E-Print Network [OSTI]

    Schirmacher, Walter

    Inelastic neutron and low-frequency Raman scattering in a niobium-phosphate glass for Raman gain: Raman scattering; Neutron scattering; Raman gain; Boson peak We present measurements of the vibrational, extracted from specific-heat or neutron scattering measurements [7,8]. Only very recently two of the present

  12. Measurement of blood analytes in turbid biological tissue using near-infrared Raman spectroscopy

    E-Print Network [OSTI]

    Koo, Tae-Woong, 1974-

    2001-01-01T23:59:59.000Z

    Concentrations of blood constituents provide diagnostic information in clinical procedures. Among the medical community, there is great interest in developing an optical method of concentration measurements that eliminates ...

  13. Raman Nanometrology of Graphene

    E-Print Network [OSTI]

    Calizo, Irene Gonzales

    2009-01-01T23:59:59.000Z

    13 Optical image of the graphene layers. . . . . .Micro-Raman Spectroscopy of Grapheneand Graphene Multi-Layers . . . . Raman Spectroscopy

  14. Rayleigh/Raman/LIF measurements in a turbulent lean premixed combustor

    SciTech Connect (OSTI)

    Nandula, S.P.; Pitz, R.W. [Vanderbilt Univ., Nashville, TN (United States). Dept. of Mechanical Engineering; Barlow, R.S.; Fiechtner, G.J. [Sandia National Labs., Albuquerque, NM (United States)

    1995-12-31T23:59:59.000Z

    Much of the industrial electrical generation capability being added worldwide is gas-turbine engine based and is fueled by natural gas. These gas-turbine engines use lean premixed (LP) combustion to meet the strict NO{sub x} emission standards, while maintaining acceptable levels of CO. In conventional, diffusion flame gas turbine combustors, large amount of NO{sub x} forms in the hot stoichiometric zones via the Zeldovich (thermal) mechanism. Hence, lean premixed combustors are rapidly becoming the norm, since they are specifically designed to avoid these hot stoichiometric zones and the associated thermal NO{sub x}. However, considerable research and development are still required to reduce the NO{sub x} levels (25-40 ppmvd adjusted to 15% O{sub 2} with the current technology), to the projected goal of under 10 ppmvd by the turn of the century. Achieving this objective would require extensive experiments in LP natural gas (or CH{sub 4}) flames for understanding the combustion phenomena underlying the formation of the exhaust pollutants. Although LP combustion is an effective way to control NO{sub x}, the downside is that it increases the CO emissions. The formation and destruction of the pollutants (NO{sub x} and CO) are strongly affected by the fluid mechanics, the finite-rate chemistry, and their (turbulence-chemistry) interactions. Hence, a thorough understanding of these interactions is vital for controlling and reducing the pollutant emissions. The present research is contributing to this goal by providing a detailed nonintrusive laser based data set with good spatial and temporal resolutions of the pollutants (NO and CO) along with the major species, temperature, and OH. The measurements reported in this work, along with the existing velocity data on a turbulent LP combustor burning CH{sub 4}, would provide insight into the turbulence-chemistry interactions and their effect on pollutant formation.

  15. Using CO2 Lidar for Standoff Detection of a Perfluorocarbon Tracer in Air

    SciTech Connect (OSTI)

    Heiser,J.H.; Smith, S.; Sedlacek, A.

    2008-02-06T23:59:59.000Z

    The Tag, Track and Location System Program (TTL) is investigating the use of PFTs as tracers for tagging and tracking items of interest or fallen soldiers. In order for the tagging and tracking to be valuable there must be a location system that can detect the PFTs. This report details the development of an infrared lidar platform for standoff detection of PFTs released into the air from a tagged object or person. Furthering work performed using a table top lidar system in an indoor environment; a mobile mini lidar platform was assembled using an existing Raman lidar platform, a grating tunable CO{sub 2} IR laser, Judson HgCdTe detector and miscellaneous folding optics and electronics. The lidar achieved {approx}200 ppb-m sensitivity in laboratory and indoor testing and was then successfully demonstrated at an outdoor test. The lidar system was able to detect PFTs released into a vehicle from a distance of 100 meters. In its final, fully optimized configuration the lidar was capable of repeatedly detecting PFTs in the air released from tagged vehicles. Responses were immediate and clear. This report details the results of a proof-of-concept demonstration for standoff detection of a perfluorocarbon tracer (PFT) using infrared lidar. The project is part of the Tag, Track and Location System Program and was performed under a contract with Tracer Detection Technology Corp. with funding from the Office of Naval Research. A lidar capable of detecting PFT releases at distance was assembled by modifying an existing Raman lidar platform by incorporating a grating tunable CO{sub 2} IR laser, Judson HgCdTe detector and miscellaneous folding optics and electronics. The lidar achieved {approx}200 ppb-m sensitivity in laboratory and indoor testing and was successfully demonstrated at an outdoor test. The demonstration test (scripted by the sponsor) consisted of three parked cars, two of which were tagged with the PFT. The cars were located 70 (closest) to 100 meters (farthest) from the lidar (the lidar beam path was limited by site constraints and was {approx}100 meters). When one door of each of the cars was opened (sequentially), the lidar was clearly able to determine which vehicles had been tagged and which one was not. The lidar is probably capable of greater than 0.5 kilometer standoff distances based on the extreme amount of signal return achieved (so much that the system had to be de-tuned). The BNL lidar system, while optimized to the extent possible with available parts and budget, was not as sensitive as it could be. Steps to improve the lidar are detailed in this report and include using a better laser system (for more stable power output), dual wavelengths (to improve the sensitivity and allow common mode noise reduction and to allow the use of the lidar in a scanning configuration), heterodyning (for range resolved PFT detection) and an off-axis optical configuration (for improved near field sensitivity).

  16. ARM - PI Product - Raman lidar/AERI PBL Height Product

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDCnarrowbandheatProductsISDACProductsRadiative Flux

  17. Stimulated Raman scattering in large plasmas

    SciTech Connect (OSTI)

    Phillion, D.W.; Banner, D.L.

    1980-11-06T23:59:59.000Z

    Stimulated Raman scattering is of concern to laser fusion since it can create a hot electron environment which can increase the difficulty of achieving high final fuel densities. In earlier experiments with one micron laser light, the energy measured in Raman-scattered light has been insignificant. But these experiments were done with, at most, about 100 joules of laser energy. The Raman instability has a high threshold which also requires a large plasma to be irradiated with a large diameter spot. Only with a long interaction length can the Raman-scattered light wave convectively grow to a large amplitude, and only in recent long pulse, high energy experiments (4000 joules in 2 ns) at the Shiva laser facility have we observed as much as several percent of the laser light to be Raman-scattered. We find that the Raman instability has a much lower intensity threshold for longer laser pulselength and larger laser spot size on a solid target.

  18. Ultraviolet Resonant Raman Enhancements in the Detection of Explosives

    SciTech Connect (OSTI)

    Short, B J; Carter, J C; Gunter, D; Hovland, P; Jagode, H; Karavanic, K; Marin, G; Mellor-Crummey, J; Moore, S; Norris, B; Oliker, L; Olschanowsky, C; Roth, P C; Schulz, M; Shende, S; Snavely, A; Spear, W

    2009-06-03T23:59:59.000Z

    Raman-based spectroscopy is potentially militarily useful for standoff detection of high explosives. Normal (non-resonance) and resonance Raman spectroscopies are both light scattering techniques that use a laser to measure the vibrational spectrum of a sample. In resonance Raman, the laser is tuned to match the wavelength of a strong electronic absorbance in the molecule of interest, whereas, in normal Raman the laser is not tuned to any strong electronic absorbance bands. The selection of appropriate excitation wavelengths in resonance Raman can result in a dramatic increase in the Raman scattering efficiency of select band(s) associated with the electronic transition. Other than the excitation wavelength, however, resonance Raman is performed experimentally the same as normal Raman. In these studies, normal and resonance Raman spectral signatures of select solid high explosive (HE) samples and explosive precursors were collected at 785 nm, 244 nm and 229 nm. Solutions of PETN, TNT, and explosive precursors (DNT & PNT) in acetonitrile solvent as an internal Raman standard were quantitatively evaluated using ultraviolet resonance Raman (UVRR) microscopy and normal Raman spectroscopy as a function of power and select excitation wavelengths. Use of an internal standard allowed resonance enhancements to be estimated at 229 nm and 244 nm. Investigations demonstrated that UVRR provided {approx}2000-fold enhancement at 244 nm and {approx}800-fold improvement at 229 nm while PETN showed a maximum of {approx}25-fold at 244 nm and {approx}190-fold enhancement at 229 nm solely from resonance effects when compared to normal Raman measurements. In addition to the observed resonance enhancements, additional Raman signal enhancements are obtained with ultraviolet excitation (i.e., Raman scattering scales as !4 for measurements based on scattered photons). A model, based partly on the resonance Raman enhancement results for HE solutions, is presented for estimating Raman enhancements for solid HE samples.

  19. Comparison of Two Independent LIDAR-Based Pitch Control Designs

    SciTech Connect (OSTI)

    Dunne, F.; Schlipf, D.; Pao, L. Y.

    2012-08-01T23:59:59.000Z

    Two different lidar-based feedforward controllers have previously been designed for the NREL 5 MW wind turbine model under separate studies. Feedforward controller A uses a finite-impulse-response design, with 5 seconds of preview, and three rotating lidar measurements. Feedforward controller B uses a static-gain design, with the preview time defined by the pitch actuator dynamics, a simulation of a real nacelle-based scanning lidar system, and a lowpass filter defined by the lidar configuration. These controllers are now directly compared under the same lidar configuration, in terms of fatigue load reduction, rotor speed regulation, and power capture. The various differences in design choices are discussed and compared. We also compare frequency plots of individual pitch feedforward and collective pitch feedforward load reductions, and we see that individual pitch feedforward is effective mainly at the once-per-revolution and twice-per-revolution frequencies. We also explain how to determine the required preview time by breaking it down into separate parts, and we then compare it to the expected preview time available.

  20. Turbine Reliability and Operability Optimization through the use of Direct Detection Lidar Final Technical Report

    SciTech Connect (OSTI)

    Johnson, David K; Lewis, Matthew J; Pavlich, Jane C; Wright, Alan D; Johnson, Kathryn E; Pace, Andrew M

    2013-02-01T23:59:59.000Z

    The goal of this Department of Energy (DOE) project is to increase wind turbine efficiency and reliability with the use of a Light Detection and Ranging (LIDAR) system. The LIDAR provides wind speed and direction data that can be used to help mitigate the fatigue stress on the turbine blades and internal components caused by wind gusts, sub-optimal pointing and reactionary speed or RPM changes. This effort will have a significant impact on the operation and maintenance costs of turbines across the industry. During the course of the project, Michigan Aerospace Corporation (MAC) modified and tested a prototype direct detection wind LIDAR instrument; the resulting LIDAR design considered all aspects of wind turbine LIDAR operation from mounting, assembly, and environmental operating conditions to laser safety. Additionally, in co-operation with our partners, the National Renewable Energy Lab and the Colorado School of Mines, progress was made in LIDAR performance modeling as well as LIDAR feed forward control system modeling and simulation. The results of this investigation showed that using LIDAR measurements to change between baseline and extreme event controllers in a switching architecture can reduce damage equivalent loads on blades and tower, and produce higher mean power output due to fewer overspeed events. This DOE project has led to continued venture capital investment and engagement with leading turbine OEMs, wind farm developers, and wind farm owner/operators.

  1. Comprehensive study of the influence of different environments on degradation processes in F8BT: Correlating optoelectronic properties with Raman measurements

    SciTech Connect (OSTI)

    Linde, Sivan; Shikler, Rafi [Department of Electrical and Computer Engineering, Ben Gurion University of the Negev, Beer-Sheva 84015 (Israel)] [Department of Electrical and Computer Engineering, Ben Gurion University of the Negev, Beer-Sheva 84015 (Israel)

    2013-10-28T23:59:59.000Z

    There is a growing interest in conjugated polymers from both industrial and academic points of views. The reasons are their tunable optoelectronic properties, ease of production, and excellent mechanical properties. However, the ease with which their optoelectronic properties are tunable make devices based on them prone to fast degradation and therefore, short life time. The issue of degradation of organic based optoelectronic devices is the topic of many ongoing researches. However, much less attention is given to degradation processes of the individual components of the devices and their dependence on the environmental conditions. In this work, we report on the degradation of a film of a polyfluorene block copolymer F8BT that is used in a variety of optoelectronic devices under different environments: Sun exposure, heating, and UV exposure in inert and ambient conditions. Degradation was observed in most of the optoelectronic properties of the film. Topographic measurements did not show observable changes of the film morphology following degradation. However, Raman spectroscopy measurements show changes that indicate degradation in one of the building blocks of the copolymer that is associated with electron's conduction. The absolute value of the correlation coefficient between the decrease in the Raman signal and the decrease in the optoelectronic properties is larger than 0.95 under sun exposure it is larger than 0.8 under all other ambient exposures and smaller than 0.65 under inert conditions. These results support the assumption that Oxygen, not necessarily through photo-oxidation, and also water play an important role in the degradation process and indicate the part of the polymer that is most susceptible to degradation.

  2. Lidar fluorosensing of mineral oil spills on the sea surface

    E-Print Network [OSTI]

    Oldenburg, Carl von Ossietzky Universität

    be discriminated from heavy fuel, and from less harmful substances like fish oil or vegetable oil, Fig. 3, whichLidar fluorosensing of mineral oil spills on the sea surface Theo Hengstermann and Rainer Reuter Airborne .fluorosensor measurements over maritime oil spills show that this method enables a sensitive

  3. High fidelity nanohole enhanced Raman spectroscopy.

    SciTech Connect (OSTI)

    Bahns, J. T.; Guo, Q.; Gray, S. K.; Jaeger, H. M.; Chen, L.; Montgomery, J. M.; Univ. of Chicago

    2009-01-01T23:59:59.000Z

    Surface enhanced Raman spectroscopy (SERS) is a sensitive technique that can even detect single molecules. However, in many SERS applications, the strongly inhomogeneous distribution of intense local fields makes it very difficult for a quantitive assessment of the fidelity, or reproducibility of the signal, which limits the application of SERS. Herein, we report the development of exceptionally high-fidelity hole-enhanced Raman spectroscopy (HERS) from ordered, 2D hexagonal nanohole arrays. We take the fidelity f to be a measure of the percent deviation of the Raman peaks from measurement to measurement. Overall, area averaged fidelities for 12 gold array samples ranged from f {approx} 2-15% for HERS using aqueous R6G molecules. Furthermore, intensity modulations of the enhanced Raman spectra were measured for the first time as a function of polarization angle. The best of these measurements, which focus on static laser spots on the sample, could be consistent with even higher fidelities than the area-averaged results. Nanohole arrays in silver provided supporting polarization measurements and a more complete enhanced Raman fingerprint for phenylalanine molecules. We also carried out finite-difference time-domain calculations to assist in the interpretation of the experiments, identifying the polarization dependence as possibly arising from hole-hole interactions. Our results represent a step toward making quantitative and reproducible enhanced Raman measurements possible and also open new avenues for a large-scale source of highly uniform hot spots.

  4. Finite temperature effects on the X-ray absorption spectra of lithium compounds: First-principles interpretation of X-ray Raman measurements

    SciTech Connect (OSTI)

    Pascal, Tod A.; Prendergast, David, E-mail: dgprendergast@lbl.gov [The Molecular Foundry, Materials Science Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, California 94720 (United States)] [The Molecular Foundry, Materials Science Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, California 94720 (United States); Boesenberg, Ulrike; Kostecki, Robert; Richardson, Thomas J. [Environmental Energy Technologies Division, LBNL, Berkeley, California 94720 (United States)] [Environmental Energy Technologies Division, LBNL, Berkeley, California 94720 (United States); Weng, Tsu-Chien; Sokaras, Dimosthenis; Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford, California 94720 (United States)] [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford, California 94720 (United States); McDermott, Eamon; Moewes, Alexander [University of Saskatchewan, Department of Physics and Engineering Physics, Saskatoon, Saskatchewan S7N 5E2 (Canada)] [University of Saskatchewan, Department of Physics and Engineering Physics, Saskatoon, Saskatchewan S7N 5E2 (Canada); Cabana, Jordi [Environmental Energy Technologies Division, LBNL, Berkeley, California 94720 (United States) [Environmental Energy Technologies Division, LBNL, Berkeley, California 94720 (United States); Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60605 (United States)

    2014-01-21T23:59:59.000Z

    We elucidate the role of room-temperature-induced instantaneous structural distortions in the Li K-edge X-ray absorption spectra (XAS) of crystalline LiF, Li{sub 2}SO{sub 4}, Li{sub 2}O, Li{sub 3}N, and Li{sub 2}CO{sub 3} using high resolution X-ray Raman spectroscopy (XRS) measurements and first-principles density functional theory calculations within the eXcited electron and Core Hole approach. Based on thermodynamic sampling via ab initio molecular dynamics simulations, we find calculated XAS in much better agreement with experiment than those computed using the rigid crystal structure alone. We show that local instantaneous distortion of the atomic lattice perturbs the symmetry of the Li 1s core-excited-state electronic structure, broadening spectral line-shapes and, in some cases, producing additional spectral features. The excellent agreement with high-resolution XRS measurements validates the accuracy of our first-principles approach to simulating XAS, and provides both accurate benchmarks for model compounds and a predictive theoretical capability for identification and characterization of multi-component systems, such as lithium-ion batteries, under working conditions.

  5. airborne oceanographic lidar: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Channels Landslides Spatial Cognition The emergence of airborne lidar data cognition and perception, we also explore the notion that the ongoing use of lidar enables...

  6. airborne aura lidar: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Channels Landslides Spatial Cognition The emergence of airborne lidar data cognition and perception, we also explore the notion that the ongoing use of lidar enables...

  7. Aerosol plume transport and transformation in high spectral resolution lidar measurements and WRF-Flexpart simulations during the MILAGRO Field Campaign

    E-Print Network [OSTI]

    de Foy, B.

    The Mexico City Metropolitan Area (MCMA) experiences high loadings of atmospheric aerosols from anthropogenic sources, biomass burning and wind-blown dust. This paper uses a combination of measurements and numerical ...

  8. Bachelor thesis: "Validation of an engineering model of the near wake wind field of wind turbines based on nacelle based lidar measurements"

    E-Print Network [OSTI]

    Peinke, Joachim

    , in an early stage of wind farm layout optimisation and wind turbine loading calculation in wind farms by Ainslie[1], This is widely used in the industry for wind farming purposes. Scope During this project analysis are performed of near wake measurements of a 5 MW wind turbine at the offshore test field alpha

  9. Portable raman explosives detection

    SciTech Connect (OSTI)

    Moore, David Steven [Los Alamos National Laboratory; Scharff, Robert J [Los Alamos National Laboratory

    2008-01-01T23:59:59.000Z

    Recent advances in portable Raman instruments have dramatically increased their application to emergency response and forensics, as well as homeland defense. This paper reviews the relevant attributes and disadvantages of portable Raman spectroscopy, both essentially and instrumentally, to the task of explosives detection in the field.

  10. URBAN MODELING FROM LIDAR DATA IN AN INTEGRATED GIS ENVIRONMENT

    E-Print Network [OSTI]

    Shan, Jie

    . In fact, the first satellites carrying lidar sensors, Alissa, Balkan-1, and Balkan-2 are scheduled

  11. Meas. Sci. Technol. 10 (1999) 11781184. Printed in the UK PII: S0957-0233(99)06575-3 Submarine lidar for seafloor

    E-Print Network [OSTI]

    Oldenburg, Carl von Ossietzky Universität

    for the detection of dissolved and sunken pollutants. One of these instruments is the submarine lidar, combining: fluorescence lidar, range-gating video, seafloor monitoring 1. Submarine sensor network for pollution of Oldenburg, Laser Remote Sensing Group), · an acoustic sensor for measuring the acoustic impedance

  12. Composition and strain in thin Si{sub 1-x}Ge{sub x} virtual substrates measured by micro-Raman spectroscopy and x-ray diffraction

    SciTech Connect (OSTI)

    Perova, T. S.; Wasyluk, J.; Waldron, A. [Department of Electronic and Electrical Engineering, Trinity College, University of Dublin, Dublin 2 (Ireland); Lyutovich, K.; Kasper, E.; Oehme, M. [Institut fuer Halbleitertechnik, Universitaet Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart (Germany); Rode, K. [School of Physics, CRANN, Trinity College, University of Dublin, Dublin 2 (Ireland)

    2011-02-01T23:59:59.000Z

    Micro-Raman spectroscopy was employed for the determination of the germanium content, x and strain, {epsilon}, in ultrathin SiGe virtual substrates grown directly on Si by molecular beam epitaxy. The growth of highly relaxed SiGe layers was achieved by the introduction of point defects at a very low temperature during the initial stage of growth. SiGe virtual substrates with thicknesses in the range 40-200 nm with a high Ge content (up to 50%) and degree of relaxation, r, in the range 20%-100% were investigated using micro-Raman spectroscopy and x-ray diffraction (XRD) techniques. The Ge content, x, and strain, {epsilon}, were estimated from equations describing Si-Si, Si-Ge, and Ge-Ge Raman vibrational modes, modified in this study for application to thin SiGe layers. The alteration of the experimentally derived equations from previous studies was performed using independent data for x and r obtained from XRD reciprocal space maps. A number of samples consisting of a strained-silicon (s-Si) layer deposited on a SiGe virtual substrate were also analyzed. The stress value for the s-Si varied from 0.54 to 2.75 GPa, depending on the Ge-content in the virtual substrates. These results are in good agreement with theoretically predicted values.

  13. Detection and Quantitative Analysis of Chemical Species in Hanford Tank Materials Using Raman Spectroscopy Technology: FY94Florida State University Raman Spectroscopy Report

    SciTech Connect (OSTI)

    Reich, F.R.

    1997-08-11T23:59:59.000Z

    This report provides a summary of work completed in FY-94 by FSU to develop and investigate the feasibility of using Raman spectroscopy with Hanford tank waste materials. Raman performance impacts from sample morphology, including the effects of absorption, particle size, density, color and refractive index, are discussed. An algorithm for relative species concentration measurement from Raman data is presented. An Algorithm for applying Raman to tank waste core screening is presented and discussed. A library of absorption and Raman spectra are presented that support this work.

  14. Probing Nanoscale Surface Enhanced Raman Scattering Fluctuation...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nanoscale Surface Enhanced Raman Scattering Fluctuation Dynamics using Correalted AFM and Confocal Ultramicroscopy. Probing Nanoscale Surface Enhanced Raman Scattering Fluctuation...

  15. Remote control and telescope auto-alignment system for multiangle LIDAR under development at CEILAP, Argentina

    E-Print Network [OSTI]

    Pallotta, Juan; Otero, Lidia; Chouza, Fernando; Raul, Delia; Gonzalez, Francisco; Etchegoyen, Alberto; Quel, Eduardo

    2013-01-01T23:59:59.000Z

    At CEILAP (CITEDEF-CONICET), a multiangle LIDAR is under development to monitor aerosol extinction coefficients in the frame of the CTA (Cherenkov Telescope Array) Project. This is an initiative to build the next generation of ground-based instruments to collect very high energy gamma-ray radiation (>10 GeV). The atmospheric conditions are very important for CTA observations, and LIDARs play an important role in the measurement of the aerosol optical depth at any direction. The LIDAR being developed at CEILAP was conceived to operate in harsh environmental conditions during the shifts, and these working conditions may produce misalignments. To minimize these effects, the telescopes comprising the reception unit are controlled by a self-alignment system. This paper describes the self-alignment method and hardware automation.

  16. Cirrus cloud-temperature interactions over a tropical station, Gadanki from lidar and satellite observations

    SciTech Connect (OSTI)

    S, Motty G, E-mail: mottygs@gmail.com; Satyanarayana, M., E-mail: mottygs@gmail.com; Krishnakumar, V., E-mail: mottygs@gmail.com; Dhaman, Reji k., E-mail: mottygs@gmail.com [Department of Optoelectronics, University of Kerala, Kariavattom, Trivandrum-695 581, Kerala (India)

    2014-10-15T23:59:59.000Z

    The cirrus clouds play an important role in the radiation budget of the earth's atmospheric system and are important to characterize their vertical structure and optical properties. LIDAR measurements are obtained from the tropical station Gadanki (13.5{sup 0} N, 79.2{sup 0} E), India, and meteorological indicators derived from Radiosonde data. Most of the cirrus clouds are observed near to the tropopause, which substantiates the strength of the tropical convective processes. The height and temperature dependencies of cloud height, optical depth, and depolarization ratio were investigated. Cirrus observations made using CALIPSO satellite are compared with lidar data for systematic statistical study of cirrus climatology.

  17. Highly Efficient Coherent Raman Generation

    E-Print Network [OSTI]

    Hua, Xia

    2014-08-04T23:59:59.000Z

    , and to my daughter Christina Tzu-Hsin Hua for the happiness she brings to me. vii NOMENCLATURE SpRS spontaneous Raman scattering SRS stimulated Raman scattering CARS coherent anti-Stokes Raman scattering CSRS coherent Stokes Raman scattering... wavelength at 672 nm. ................................................................................... 75 Figure 41 The electric field spectral amplitudes of the incident pump (green), Stokes (orange), and probe (red) laser pulses with normalized...

  18. Remote sensing the wind using Lidars and Sodars Ioannis Antoniou (1)

    E-Print Network [OSTI]

    masts for their mounting and the costs associated with the purchase, erection and instrumentation for wind energy applications. The first reason is that the cost (purchase, erection, instrumentation with power curve and resource assessment measurements. Both SODAR (SOund Detection And Ranging) and LIDAR

  19. Surface-enhanced Raman scattering (SERS) dosimeter and probe

    DOE Patents [OSTI]

    Vo-Dinh, Tuan (Knoxville, TN)

    1995-01-01T23:59:59.000Z

    A dosimeter and probe for measuring exposure to chemical and biological compounds is disclosed. The dosimeter or probe includes a collector which may be analyzed by surface-enhanced Raman spectroscopy. The collector comprises a surface-enhanced Raman scattering-active material having a coating applied thereto to improve the adsorption properties of the collector. The collector may also be used in automated sequential devises, in probe array devices.

  20. Raman accumulator as a fusion laser driver

    DOE Patents [OSTI]

    George, E.V.; Swingle, J.C.

    1982-03-31T23:59:59.000Z

    Apparatus for simultaneous laser pulse amplification and compression, using multiple pass Raman scattering in one Raman cell and pulse switchout from the optical cavity through use of a dichroic device associated with the Raman cell.

  1. JOURNAL OF RAMAN SPECTROSCOPY J. Raman Spectrosc. 2007; 38: 853858

    E-Print Network [OSTI]

    Lombardi, John R.

    with colloidal Ag following a pretreatment with HCl vapor. The SERS method allowed us to detect berberine nm excitation have been published,10,11 obtaining good quality Raman data from paper or silk dyed data collection methods, such as shifted subtracted Raman difference spectroscopy (SSRDS)12­14 have

  2. Angular output of hollow, metal-lined, waveguide Raman sensors

    SciTech Connect (OSTI)

    Biedrzycki, Stephen; Buric, Michael P.; Falk, Joel; Woodruff, Steven D.

    2012-04-20T23:59:59.000Z

    Hollow, metal-lined waveguides used as gas sensors based on spontaneous Raman scattering are capable of large angular collection. The collection of light from a large solid angle implies the collection of a large number of waveguide modes. An accurate estimation of the propagation losses for these modes is required to predict the total collected Raman power. We report a theory/experimental comparison of the Raman power collected as a function of the solid angle and waveguide length. New theoretical observations are compared with previous theory appropriate only for low-order modes. A cutback experiment is demonstrated to verify the validity of either theory. The angular distribution of Raman light is measured using aluminum and silver-lined waveguides of varying lengths.

  3. Systematic Sampling of Scanning Lidar Swaths

    E-Print Network [OSTI]

    Marcell, Wesley Tyler

    2011-02-22T23:59:59.000Z

    of the requirements for the degree of MASTER OF SCIENCE Approved by: Co-Chairs of Committee, Marian Eriksson Sorin Pospescu Committee Members, Cristine Morgan Ross Nelson Head of Department, Steven Whisenant December 2009 Major Subject: Forestry... iii ABSTRACT Systematic Sampling of Scanning Lidar Swaths. (December 2009) Wesley Tyler Marcell, B.S., Texas A&M University Co-Chairs of Advisory Committee: Dr. Marian Eriksson Dr. Sorin...

  4. Lidar techniques for search and rescue

    SciTech Connect (OSTI)

    Cabral, W.L.

    1985-01-01T23:59:59.000Z

    Four techniques for using LIDAR in Search and Rescue Operations will be discussed. The topic will include laser retroreflection, laser-induced fluorescence in the visible, laser-induced fluorescence during daylight hours, and laser-induced fluorescence in the uv. These techniques use high-repetition rate lasers at a variety of frequencies to induce either fluorescence in dye markers or retroreflection from plastic corner cubes on life preservers and other emergency markers.

  5. Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

    SciTech Connect (OSTI)

    Meyer, Matthew W. [Ames Laboratory

    2013-03-14T23:59:59.000Z

    This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

  6. Polarized Raman scattering of single ZnO nanorod

    SciTech Connect (OSTI)

    Yu, J. L., E-mail: jlyu@semi.ac.cn; Lai, Y. F., E-mail: laiyunfeng@gmail.com; Wang, Y. Z.; Cheng, S. Y. [Institute of Micro/Nano Devices and Solar Cells, School of Physics and Information Engineering, Fuzhou University, Fuzhou (China); Chen, Y. H. [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

    2014-01-21T23:59:59.000Z

    Polarized Raman scattering measurement on single wurtzite c-plane (001) ZnO nanorod grown by hydrothermal method has been performed at room temperature. The polarization dependence of the intensity of the Raman scattering for the phonon modes A{sub 1}(TO), E{sub 1}(TO), and E{sub 2}{sup high} in the ZnO nanorod are obtained. The deviations of polarization-dependent Raman spectroscopy from the prediction of Raman selection rules are observed, which can be attributed to the structure defects in the ZnO nanorod as confirmed by the comparison of the transmission electron microscopy, photoluminescence spectra as well as the polarization dependent Raman signal of the annealed and unannealed ZnO nanorod. The Raman tensor elements of A{sub 1}(TO) and E{sub 1}(TO) phonon modes normalized to that of the E{sub 2}{sup high} phonon mode are |a/d|=0.32±0.01,?|b/d|=0.49±0.02, and |c/d|=0.23±0.01 for the unannealed ZnO nanorod, and |a/d|=0.33±0.01,?|b/d|=0.45±0.01, and |c/d|=0.20±0.01 for the annealed ZnO nanorod, which shows strong anisotropy compared to that of bulk ZnO epilayer.

  7. A comparison of cloud top heights computed from airborne lidar and MAS radiance data using CO2 slicing

    E-Print Network [OSTI]

    Sheridan, Jennifer

    A comparison of cloud top heights computed from airborne lidar and MAS radiance data using CO2 in assessing the accuracy of the CO2-slicing cloud height algorithm. Infrared measurements of upwelling which included various single- layer and multilayer cloud conditions. Overall, the CO2-slicing method

  8. Raman spectroscopy of shocked water

    SciTech Connect (OSTI)

    Holmes, N.C.; Mitchell, A.C.; Nellis, W.J.; Graham, W.B.; Walrafen, G.E.

    1983-07-01T23:59:59.000Z

    Raman scattering has been used extensively to study the vibrational and rotational properties of molecules under a variety of conditions. Here, interest is in the behavior of water molecules shocked to high pressures and temperatures. Behind the shock front the water molecules undergo changes in bonding and the molecules may become ionized. Raman spectroscopy can be used to determine the molecular species behind the shock front. In addition, changes in Raman spectra can yield information regarding inter- and intramolecular potentials and the temperature behind the shock front.

  9. Surface-Enhanced Resonance Raman Scattering (SERRS) Using Au Nanohole Arrays on Optical Fiber Tips

    E-Print Network [OSTI]

    Brolo, Alexandre G.

    Surface-Enhanced Resonance Raman Scattering (SERRS) Using Au Nanohole Arrays on Optical Fiber Tips nanoholes arrays were fabricated on gold films deposited on the tips of single- mode optical fibers. The optical fiber devices were used for surface- enhanced resonance Raman scattering (SERRS) measurements

  10. THE JOURNAL OF CHEMICAL PHYSICS 134, 234310 (2011) False estimates of stimulated Raman pumping efficiency caused

    E-Print Network [OSTI]

    Zare, Richard N.

    THE JOURNAL OF CHEMICAL PHYSICS 134, 234310 (2011) False estimates of stimulated Raman pumping June 2011; published online 20 June 2011) One technique for measuring the fraction of molecules pumped to the excited state in stimulated Raman pumping (SRP) is to record the depletion of molecules in the lower state

  11. Ris {R{1127(EN) Lidar data used in the COFIN

    E-Print Network [OSTI]

    3.1 Generation of arti cial smoke 7 4 Data processing 8 4.1 The lidar equation 8 4.2 Backscatter, see below. In FLADIS the smoke were added to an initial heavy gas plume. 2 Experimental design Figures response. However, the Lidar does have a averaging volume due to the leng

  12. Airborne lidar detection and characterization of internal waves in a

    E-Print Network [OSTI]

    Shaw, Joseph A.

    , Graduate School of Oceanography, Narragansett, Rhode Island 02874 Abstract. A dual-polarization lidar though the contrast is low (2%). Combined with the lidar profile, the total energy of the internal wave heating at the surface and/or fresh water input from terrestrial runoff or melting ice create a layer

  13. Validation of Innovative Exploration Technologies for Newberry Volcano: LIDAR of Newberry Volcano 2012

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jaffe, Todd

    Validation of Innovative Exploration Technologies for Newberry Volcano: LIDAR of Newberry Volcano 2012

  14. DOE/SC-ARM/TR-120 Raman Lidar Profiles-Temperature

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration wouldDECOMPOSITION OF CALCIUMCOSTDOENuclear1382 THEDOE0-354-1502225

  15. Three dimensional winds: A maximum cross-correlation application to elastic lidar data

    SciTech Connect (OSTI)

    Buttler, W.T.

    1996-05-01T23:59:59.000Z

    Maximum cross-correlation techniques have been used with satellite data to estimate winds and sea surface velocities for several years. Los Alamos National Laboratory (LANL) is currently using a variation of the basic maximum cross-correlation technique, coupled with a deterministic application of a vector median filter, to measure transverse winds as a function of range and altitude from incoherent elastic backscatter lidar (light detection and ranging) data taken throughout large volumes within the atmospheric boundary layer. Hourly representations of three-dimensional wind fields, derived from elastic lidar data taken during an air-quality study performed in a region of complex terrain near Sunland Park, New Mexico, are presented and compared with results from an Environmental Protection Agency (EPA) approved laser doppler velocimeter. The wind fields showed persistent large scale eddies as well as general terrain-following winds in the Rio Grande valley.

  16. Raman Spectroscopy of Carbon Dust Samples from NSTX

    SciTech Connect (OSTI)

    Y. Raitses, C.H. Skinner, F. Jiang and T.S. Duffy

    2008-02-21T23:59:59.000Z

    The Raman spectrum of dust particles exposed to the NSTX plasma is different from the spectrum of unexposed particles scraped from an unused graphite tile. For the unexposed particles, the high energy G-mode peak (Raman shift ~1580 cm-1) is much stronger than the defect-induced D-mode peak (Raman shift ~ 1350 cm-1), a pattern that is consistent with Raman spectrum for commercial graphite materials. For dust particles exposed to the plasma, the ratio of G-mode to D-mode peaks is lower and becomes even less than 1. The Raman measurements indicate that the production of carbon dust particles in NSTX involves modifications of the physical and chemical structure of the original graphite material. These modifications are shown to be similar to those measured for carbon deposits from atmospheric pressure helium arc discharge with an ablating anode electrode made from a graphite tile material. We also demonstrate experimentally that heating to 2000-2700 K alone can not explain the observed structural modifications indicating that they must be due to higher temperatures needed for graphite vaporization, which is followed either by condensation or some plasma-induced processes leading to the formation of more disordered forms of carbon material than the original graphite.

  17. Differential high-resolution stimulated CW Raman spectroscopy of hydrogen in a hollow-core fiber

    E-Print Network [OSTI]

    Westergaard, Philip G; Petersen, Jan C

    2015-01-01T23:59:59.000Z

    We demonstrate sensitive high-resolution stimulated Raman measurements of hydrogen using a hollow-core photonic crystal fiber (HC-PCF). The Raman transition is pumped by a narrow linewidth (<50 kHz) 1064 nm continuous-wave (CW) fiber laser. The probe light is produced by a homebuilt CW optical parametric oscillator (OPO), tunable from around 800 nm to 1300 nm (linewidth ~ 5 MHz). These narrow linewidth lasers allow for an excellent spectral resolution of approximately 10^-4 cm^(-1). The setup employs a differential measurement technique for noise rejection in the probe beam, which also eliminates background signals from the fiber. With the high sensitivity obtained, Raman signals were observed with only a few mW of optical power in both the pump and probe beams. This demonstration allows for high resolution Raman identification of molecules and quantification of Raman signal strengths.

  18. Active probing of cloud multiple scattering, optical depth, vertical thickness, and liquid water content using wide-angle imaging LIDAR.

    SciTech Connect (OSTI)

    Love, Steven P.; Davis, A. B. (Anthony B.); Rohde, C. A. (Charles A.); Tellier, L. L. (Larry L.); Ho, Cheng,

    2002-01-01T23:59:59.000Z

    At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is the essence of our unique instrument, Wide Angle Imaging Lidar (WAIL). In effect, WAIL produces wide-field (60-degree full-angle) 'movies' of the scattering process and records the cloud's radiative Green functions. A direct data product of WAIL is the distribution of photon path lengths resulting from multiple scattering in the cloud. Following insights from diffusion theory, we can use the measured Green functions to infer the physical thickness and optical depth of the cloud layer, and, from there, estimate the volume-averaged liquid water content. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Here we present recent WAIL data oti various clouds and discuss the extension of WAIL to full diurnal monitoring by means of an ultra-narrow magneto-optic atomic line filter for daytime measurements.

  19. UV resonance Raman analysis of trishomocubane and diamondoid dimers

    SciTech Connect (OSTI)

    Meinke, Reinhard, E-mail: rene@physik.tu-berlin.de; Thomsen, Christian; Maultzsch, Janina [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin (Germany)] [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin (Germany); Richter, Robert; Merli, Andrea [Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin (Germany)] [Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin (Germany); Fokin, Andrey A. [Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen (Germany) [Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen (Germany); Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev (Ukraine); Koso, Tetyana V.; Schreiner, Peter R. [Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen (Germany)] [Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen (Germany); Rodionov, Vladimir N. [Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev (Ukraine)] [Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev (Ukraine)

    2014-01-21T23:59:59.000Z

    We present resonance Raman measurements of crystalline trishomocubane and diamantane dimers containing a C=C double bond. Raman spectra were recorded with excitation energies between 2.33 eV and 5.42 eV. The strongest enhancement is observed for the C=C stretch vibration and a bending mode involving the two carbon atoms of the C=C bond, corresponding to the B{sub 2g} wagging mode of ethylene. This is associated with the localization of the ?-HOMO and LUMO and the elongation of the C=C bond length and a pyramidalization of the two sp{sup 2}-hybridized carbon atoms at the optical excitation. The observed Raman resonance energies of the trishomocubane and diamantane dimers are significantly lower than the HOMO-LUMO gaps of the corresponding unmodified diamondoids.

  20. Standoff ultraviolet raman scattering detection of trace levels of explosives.

    SciTech Connect (OSTI)

    Kulp, Thomas J.; Bisson, Scott E.; Reichardt, Thomas A.

    2011-10-01T23:59:59.000Z

    Ultraviolet (UV) Raman scattering with a 244-nm laser is evaluated for standoff detection of explosive compounds. The measured Raman scattering albedo is incorporated into a performance model that focused on standoff detection of trace levels of explosives. This model shows that detection at {approx}100 m would likely require tens of seconds, discouraging application at such ranges, and prohibiting search-mode detection, while leaving open the possibility of short-range point-and-stare detection. UV Raman spectra are also acquired for a number of anticipated background surfaces: tile, concrete, aluminum, cloth, and two different car paints (black and silver). While these spectra contained features in the same spectral range as those for TNT, we do not observe any spectra similar to that of TNT.

  1. Cone penetrometer fiber optic raman spectroscopy probe assembly

    DOE Patents [OSTI]

    Kyle, Kevin R. (Brentwood, CA); Brown, Steven B. (Livermore, CA)

    2000-01-01T23:59:59.000Z

    A chemically and mechanically robust optical Raman spectroscopy probe assembly that can be incorporated in a cone penetrometer (CPT) for subsurface deployment. This assembly consists of an optical Raman probe and a penetrometer compatible optical probe housing. The probe is intended for in-situ chemical analysis of chemical constituents in the surrounding environment. The probe is optically linked via fiber optics to the light source and the detection system at the surface. A built-in broadband light source provides a strobe method for direct measurement of sample optical density. A mechanically stable sapphire window is sealed directly into the side-wall of the housing using a metallic, chemically resistant, hermetic seal design. This window permits transmission of the interrogation light beam and the resultant signal. The spectroscopy probe assembly is capable of accepting Raman, Laser induced Fluorescence, reflectance, and other optical probes with collimated output for CPT deployment.

  2. Multi-wavelength Raman scattering of nanostructured Al-doped zinc oxide

    SciTech Connect (OSTI)

    Russo, V.; Ghidelli, M.; Gondoni, P. [Dipartimento di Energia and NEMAS, Center for Nanoengineered Materials and Surfaces, Politecnico di Milano, via Ponzio 34/3, I-20133 Milano (Italy); Casari, C. S.; Li Bassi, A. [Dipartimento di Energia and NEMAS, Center for Nanoengineered Materials and Surfaces, Politecnico di Milano, via Ponzio 34/3, I-20133 Milano (Italy); Center for Nano Science and Technology PoliMI, Istituto Italiano di Tecnologia, Via Pascoli 70/3, I-20133 Milano (Italy)

    2014-02-21T23:59:59.000Z

    In this work we present a detailed Raman scattering investigation of zinc oxide and aluminum-doped zinc oxide (AZO) films characterized by a variety of nanoscale structures and morphologies and synthesized by pulsed laser deposition under different oxygen pressure conditions. The comparison of Raman spectra for pure ZnO and AZO films with similar morphology at the nano/mesoscale allows to investigate the relation between Raman features (peak or band positions, width, relative intensity) and material properties such as local structural order, stoichiometry, and doping. Moreover Raman measurements with three different excitation lines (532, 457, and 325?nm) point out a strong correlation between vibrational and electronic properties. This observation confirms the relevance of a multi-wavelength Raman investigation to obtain a complete structural characterization of advanced doped oxide materials.

  3. Atmospheric Data, Images, and Animations from Lidar Instruments used by the University of Wisconsin Lidar Group

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The Space Science and Engineering Center is a research and development center affiliated with the University of Wisconsin-Madison’s Graduate School. Its primary focus is on geophysical research and technology to enhance understanding of the atmosphere of Earth, the other planets in the Solar System, and the cosmos. SSEC develops new observing tools for spacecraft, aircraft, and ground-based platforms, and models atmospheric phenomena. The Center receives, manages and distributes huge amounts of geophysical data and develops software to visualize and manipulate these data for use by researchers and operational meteorologists all over the world.[Taken from About SSEC at http://www.ssec.wisc.edu/overview/] A huge collection of data products, images, and animations comes to the SSEC from the University of Wisconsin Lidar Group. Contents of this collection include: • An archive of thousands of Lidar images acquired before 2004 • Arctic HSRL, MMCR, PAERI, MWR, Radiosonde, and CRAS forecast data Data after May 1, 2004 • MPEG animations and Lidar Multiple Scattering Models

  4. TEMPERATURE-DEPENDENT RAMAN SPECTROSCOPY OF FULLERENE AND CARBORANE NANOCAR WHEELS

    E-Print Network [OSTI]

    Mellor-Crummey, John

    step is to compare the energy shift in these vibrational modes with the temperature dependent tunneling. A thermocouple attached to the surface of the heater mount is used to measure the device's temperature. Raman

  5. airborne lidar mapping: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A minimum height of 1 m was applied to define woody understorey. Critical to this process were a Digital Terrain Model (extracted from the leaf-off last return LiDAR data)...

  6. BPA's LiDAR program maps corridor to success

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    analyzed by BPA's LiDAR program. The animation was produced by Ryan Beck and Drew Thompson in BPA's Geospatial Services group. Sometimes the pace of change is imperceptible,...

  7. absorption lidar dial: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Topic Index 1 Development of an eye-safe diode-laser-based micro-pulse differential absorption lidar (MP-dial) for atmospheric water-vapor and aerosol studies. Open Access Theses...

  8. A study on Raman Injection Laser

    E-Print Network [OSTI]

    Liu, Debin

    2005-11-01T23:59:59.000Z

    The Raman Injection Laser is a new type of laser which is based on triply resonant stimulated Raman scattering between quantum confined states within the active region of a Quantum Cascade Laser that serves as an internal optical pump. The Raman...

  9. A versatile femtosecond stimulated Raman spectroscopy setup with tunable pulses in the visible to near infrared

    SciTech Connect (OSTI)

    Zhu, Liangdong [Department of Physics, Oregon State University, Corvallis, Oregon 97331 (United States); Liu, Weimin [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States); Fang, Chong, E-mail: Chong.Fang@oregonstate.edu [Department of Physics, Oregon State University, Corvallis, Oregon 97331 (United States); Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)

    2014-07-28T23:59:59.000Z

    We demonstrate a versatile and efficient setup to perform femtosecond stimulated Raman spectroscopy (FSRS). Technical innovations are implemented to achieve the wavelength tunability for both the picosecond narrowband Raman pump pulse and femtosecond broadband Raman probe pulse. Using a simplified one-grating scheme in a home-built second harmonic bandwidth compressor followed by a two-stage noncollinear optical parametric amplifier, we tune the Raman pump pulse from ca. 480 to 750?nm. To generate the suitable Raman probe pulse in tandem, we rely on our recently demonstrated broadband up-converted multicolor array technique that readily provides tunable broadband laser sidebands across the visible to near-infrared range. This unique setup has unparalleled flexibility for conducting FSRS. We measure the ground-state Raman spectra of a cyclohexane standard using tunable pump-probe pairs at various wavelengths across the visible region. The best spectral resolution is ?12?cm{sup ?1}. By tuning the pump wavelength closer to the electronic absorption band of a photoacid pyranine in water, we observe the pre-resonantly enhanced Raman signal. The stimulated Raman gain of the 1627?cm{sup ?1} mode is increased by over 15 times.

  10. A motor drive control system for the Lidar Polarimeter

    E-Print Network [OSTI]

    Leung, Waiming

    1977-01-01T23:59:59.000Z

    A MOTOR DRIVE CONTROL SYSTEM FOR THE LIDAR POLARIMETER A Thesis by Waiming Leung Submitted to the Graduate College of Texas A/M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCF, May 1977 Major... Subject: Electrical Engineering A MOTOR DRIVE CONTROL SYSTEM FOR THE LIDAR POLARIMETER A Thesis by Waiming Leung Approved as to style and content by: Chairman o Comm' ee ea o epartment Member Mem er May 1977 ABSTRACT A Motor Drive Control...

  11. Simulated performance of an airborne lidar wind shear detection system

    E-Print Network [OSTI]

    Griffith, Kenneth Scott

    1987-01-01T23:59:59.000Z

    SIMULATED PERFORMANCE OF AN AIRBORNE LIDAR WIND SHEAR DETECTION SYSTEM A Thesis by KENNETH SCOTT GRIFFITH Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... December 1987 Major Subject: Physics SIMULATED PERFORMANCE OF AN AIRBORNE LIDAR WIND SHEAR DETECTION SYSTEM A Thesis by KENNETH SCOTT GRIFFITH Approved as to style and content by: e . atta ar (Chair an of Committee) T omas . air, III (Member) ic...

  12. Rugged fiber optic probe for raman measurement

    DOE Patents [OSTI]

    O'Rourke, Patrick E. (Martinez, GA); Toole, Jr., William R. (Aiken, SC); Nave, Stanley E. (Evans, GA)

    1998-01-01T23:59:59.000Z

    An optical probe for conducting light scattering analysis is disclosed. The probe comprises a hollow housing and a probe tip. A fiber assembly made up of a transmitting fiber and a receiving bundle is inserted in the tip. A filter assembly is inserted in the housing and connected to the fiber assembly. A signal line from the light source and to the spectrometer also is connected to the filter assembly and communicates with the fiber assembly. By using a spring-loaded assembly to hold the fiber connectors together with the in-line filters, complex and sensitive alignment procedures are avoided. The close proximity of the filter assembly to the probe tip eliminates or minimizes self-scattering generated by the optical fiber. Also, because the probe can contact the sample directly, sensitive optics can be eliminated.

  13. Detection and quantitative analysis of chemical species in Hanford tank materials using Raman spectroscopy technology: FY94, January 1, 1994--March 31, 1995

    SciTech Connect (OSTI)

    Vickers, T.J.; Mann, C. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry

    1995-09-12T23:59:59.000Z

    This report provides a summary of work completed in FY-94 by FSU to develop and investigate the feasibility of using Raman spectroscopy with Hanford tank waste materials. Raman performance impacts from sample morphology, including the effects of absorption, particle size, density, color and refractive index, are discussed. An algorithm for relative species concentration measurement from Raman data is presented. An Algorithm for applying Raman to tank waste core screening is presented and discussed. A library of absorption and Raman spectra are presented that support this work.

  14. Ris-R-Report Investigation of turbulence measurements

    E-Print Network [OSTI]

    many times that the mean horizontal wind speed measured by a lidar over flat terrain compares very well. We then evaluate this model by comparing the theoretical results to experimental data obtained.......................................................12 3.1 What can a cw conically scanning lidar tell us about turbulence?...12 3.2 Illustration

  15. Cloud Effects on Radiative Heating Rate Profiles over Darwin using ARM and A-train Radar/Lidar Observations

    SciTech Connect (OSTI)

    Thorsen, Tyler J.; Fu, Qiang; Comstock, Jennifer M.

    2013-06-11T23:59:59.000Z

    Observations of clouds from the ground-based U.S. Department of Energy Atmospheric Radiation Measurement program (ARM) and satellite-based A-train are used to compute cloud radiative forcing profiles over the ARM Darwin, Australia site. Cloud properties are obtained from both radar (the ARM Millimeter Cloud Radar (MMCR) and the CloudSat satellite in the A-train) and lidar (the ARM Micropulse lidar (MPL) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite in the A-train) observations. Cloud microphysical properties are taken from combined radar and lidar retrievals for ice clouds and radar only or lidar only retrievals for liquid clouds. Large, statistically significant differences of up to 1.43 K/day exist between the mean ARM and A-train net cloud radiative forcing profiles. The majority of the difference in cloud radiative forcing profiles is shown to be due to a large difference in the cloud fraction above 12 km. Above this altitude the A-train cloud fraction is significantly larger because more clouds are detected by CALIPSO than by the ground-based MPL. It is shown that the MPL is unable to observe as many high clouds as CALIPSO due to being more frequently attenuated and a poorer sensitivity even in otherwise clear-sky conditions. After accounting for cloud fraction differences and instrument sampling differences due to viewing platform we determined that differences in cloud radiative forcing due to the retrieved ice cloud properties is relatively small. This study demonstrates that A-train observations are better suited for the calculation cloud radiative forcing profiles. In addition, we find that it is necessary to supplement CloudSat with CALIPSO observations to obtain accurate cloud radiative forcing profiles since a large portion of clouds at Darwin are detected by CALIPSO only.

  16. Intermodal entanglement in Raman processes

    E-Print Network [OSTI]

    Biswajit Sen; Sandip Kumar Giri; Swapan Mandal; C. H. Raymond Ooi; Anirban Pathak

    2013-01-02T23:59:59.000Z

    The operator solution of a completely quantum mechanical Hamiltonian of the Raman processes is used here to investigate the possibility of obtaining intermodal entanglement between different modes involved in the Raman processes (e.g. pump mode, Stokes mode, vibration (phonon) mode and anti-Stokes mode). Intermodal entanglement is reported between a) pump mode and anti-Stokes mode, b) pump mode and vibration (phonon) mode c) Stokes mode and vibration phonon mode, d) Stokes mode and anti-stokes mode in the stimulated Raman processes for the variation of the phase angle of complex eigenvalue $\\alpha_{1}$ of pump mode $a$. Some incidents of intermodal entanglement in the spontaneous and the partially spontaneous Raman processes are also reported. Further it is shown that the specific choice of coupling constants may produce genuine entanglement among Stokes mode, anti-Stokes mode and vibration-phonon mode. It is also shown that the two mode entanglement not identified by Duan's criterion may be identified by Hillery-Zubairy criteria. It is further shown that intermodal entanglement, intermodal antibunching and intermodal squeezing are independent phenomena.

  17. Method And System For Examining Biological Materials Using Low Power Cw Excitation Raman Spectroscopy.

    DOE Patents [OSTI]

    Alfano, Robert R. (Bronx, NY); Wang, Wubao (Flushing, NY)

    2000-11-21T23:59:59.000Z

    A method and system for examining biological materials using low-power cw excitation Raman spectroscopy. In accordance with the teachings of the invention, a low-power continuous wave (cw) pump laser beam and a low-power cw Stokes (or anti-Stokes) probe laser beam simultaneously illuminate a biological material and traverse the biological material in collinearity. The pump beam, whose frequency is varied, is used to induce Raman emission from the biological material. The intensity of the probe beam, whose frequency is kept constant, is monitored as it leaves the biological material. When the difference between the pump and probe excitation frequencies is equal to a Raman vibrational mode frequency of the biological material, the weak probe signal becomes amplified by one or more orders of magnitude (typically up to about 10.sup.4 -10.sup.6) due to the Raman emission from the pump beam. In this manner, by monitoring the intensity of the probe beam emitted from the biological material as the pump beam is varied in frequency, one can obtain an excitation Raman spectrum for the biological material tested. The present invention may be applied to in the in vivo and/or in vitro diagnosis of diabetes, heart disease, hepatitis, cancers and other diseases by measuring the characteristic excitation Raman lines of blood glucose, cholesterol, serum glutamic oxalacetic transaminase (SGOT)/serum glutamic pyruvic tansaminase (SGPT), tissues and other corresponding Raman-active body constituents, respectively. For example, it may also be used to diagnose diseases associated with the concentration of Raman-active constituents in urine, lymph and saliva It may be used to identify cancer in the breast, cervix, uterus, ovaries and the like by measuring the fingerprint excitation Raman spectra of these tissues. It may also be used to reveal the growing of tumors or cancers by measuring the levels of nitric oxide in tissue.

  18. Characterizing Aerosol Distributions and Optical Properties Using the NASA Langley High Spectral Resolution Lidar

    SciTech Connect (OSTI)

    Hostetler, Chris; Ferrare, Richard

    2013-02-14T23:59:59.000Z

    The objective of this project was to provide vertically and horizontally resolved data on aerosol optical properties to assess and ultimately improve how models represent these aerosol properties and their impacts on atmospheric radiation. The approach was to deploy the NASA Langley Airborne High Spectral Resolution Lidar (HSRL) and other synergistic remote sensors on DOE Atmospheric Science Research (ASR) sponsored airborne field campaigns and synergistic field campaigns sponsored by other agencies to remotely measure aerosol backscattering, extinction, and optical thickness profiles. Synergistic sensors included a nadir-viewing digital camera for context imagery, and, later in the project, the NASA Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP). The information from the remote sensing instruments was used to map the horizontal and vertical distribution of aerosol properties and type. The retrieved lidar parameters include profiles of aerosol extinction, backscatter, depolarization, and optical depth. Products produced in subsequent analyses included aerosol mixed layer height, aerosol type, and the partition of aerosol optical depth by type. The lidar products provided vertical context for in situ and remote sensing measurements from other airborne and ground-based platforms employed in the field campaigns and was used to assess the predictions of transport models. Also, the measurements provide a data base for future evaluation of techniques to combine active (lidar) and passive (polarimeter) measurements in advanced retrieval schemes to remotely characterize aerosol microphysical properties. The project was initiated as a 3-year project starting 1 January 2005. It was later awarded continuation funding for another 3 years (i.e., through 31 December 2010) followed by a 1-year no-cost extension (through 31 December 2011). This project supported logistical and flight costs of the NASA sensors on a dedicated aircraft, the subsequent analysis and archival of the data, and the presentation of results in conferences, workshops, and publications. DOE ASR field campaigns supported under this project included - MAX-Mex /MILAGRO (2006) - TexAQS 2006/GoMACCS (2006) - CHAPS (2007) - RACORO (2009) - CARE/CalNex (2010) In addition, data acquired on HSRL airborne field campaigns sponsored by other agencies were used extensively to fulfill the science objectives of this project and the data acquired have been made available to other DOE ASR investigators upon request.

  19. Geospatial analysis of vulnerable beach-foredune systems from decadal time series of lidar data

    E-Print Network [OSTI]

    Mitasova, Helena

    Geospatial analysis of vulnerable beach-foredune systems from decadal time series of lidar data, Geospatial analysis of vulnerable beach- foredune systems from decadal time series of lidar data, Journal densities; therefore, geospatial analysis, when applied to decadal lidar time series, needs to address

  20. Alternate spatial sampling approaches for ecosystem structure inventory using spaceborne lidar

    E-Print Network [OSTI]

    Lefsky, Michael

    used in aircraft lidar remote sensing where power, heat, and reliability are less of a concern since January 2011 Accepted 29 January 2011 Available online 23 March 2011 Keywords: Lidar Remote sensing Laser collected in transects and should be considered for future lidar remote sensing missions. © 2011 Elsevier

  1. Method And System For Examining Biological Materials Using Low Power Cw Excitation Raman Spectroscopy.

    DOE Patents [OSTI]

    Alfano, Robert R. (Bronx, NY); Wang, Wubao (Flushing, NY)

    2003-05-06T23:59:59.000Z

    A method and system for examining biological materials using low-power cw excitation Raman spectroscopy. A low-power continuous wave (cw) pump laser beam and a low-power cw Stokes (or anti-Stokes) probe laser beam simultaneously illuminate a biological material and traverse the biological material in collinearity. The pump beam, whose frequency is varied, is used to induce Raman emission from the biological material. The intensity of the probe beam, whose frequency is kept constant, is monitored as it leaves the biological material. When the difference between the pump and probe excitation frequencies is equal to a Raman vibrational mode frequency of the biological material, the weak probe signal becomes amplified by one or more orders of magnitude (typically up to about 10.sup.4 -10.sup.6) due to the Raman emission from the pump beam. In this manner, by monitoring the intensity of the probe beam emitted from the biological material as the pump beam is varied in frequency, one can obtain an excitation Raman spectrum for the biological material tested. The present invention may be applied to in the in vivo and/or in vitro diagnosis of diabetes, heart disease, hepatitis, cancers and other diseases by measuring the characteristic excitation Raman lines of blood glucose, cholesterol, serum glutamic oxalacetic transaminase (SGOT)/serum glutamic pyruvic transaminase (SGPT), tissues and other corresponding Raman-active body constituents, respectively.

  2. ARM: ARSCL: cloud boundaries from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Coulter, Richard; Widener, Kevin; Bharadwaj, Nitin; Johnson, Karen; Martin, Timothy

    ARSCL: cloud boundaries from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

  3. ARM: ARSCL: multiple outputs from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Coulter, Richard; Widener, Kevin; Bharadwaj, Nitin; Johnson, Karen; Martin, Timothy

    ARSCL: multiple outputs from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

  4. AIRBORNE HIGH SPECTRAL RESOLUTION LIDAR MEASUREMENTS OF ATMOSPHERIC AEROSOLS

    E-Print Network [OSTI]

    the evolution and transport of pollution from Mexico City. The second major experiment was the Texas Air Quality Union 2007 Joint Assembly Acapulco, Mexico May 22-25, 2007 Environmental Sciences Department Research Observations (MILAGRO) /Megacity Aerosol Experiment in Mexico City (MAX

  5. Observations of tropical cirrus properties in the pilot radiation observation experiment using lidar and the CSIRO ARM filter radiometer

    SciTech Connect (OSTI)

    Platt, C.M.R.; Young, S.A.; Manson, P.J.; Patterson, G.R. [CSIRO, Victoria (Australia)

    1995-04-01T23:59:59.000Z

    A narrow beam fast filter radiometer has been developed for the Atmospheric Radiation Measurement (ARM) Program. The radiometer is intended to operate alongside a lidar at ARM sites in a lidar/radiometer (LIRAD) configuration. The radiometer detects in three narrow bands at 8.62-, 10.86-, and 12.04-m central wavelengths in the atmospheric window. In addition, it has a variable field aperture that varies the radiance incident on the detector and also allows the field of view to be tailored to that of a lidar used in the LIRAD technique. The radiometer was deployed in the ARM Pilot Radiation Observation Experiment (PROBE) at Kavieng, Papua New Guinea in January-February 1993. The radiometer worked satisfactorily and appeared to be very stable. The radiometer was compared with a previous CSIRO radiometer and the improved performance of the ARM instrument was very evident. The ARM radiometer was also compared with a National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratories (ETL) interferometer and gave closely equivalent radiances. The LIRAD method was used at Kavieng to obtain the optical properties of cirrus clouds. Continuous observations of water vapor path obtained by the NOAA ETL microwave radiometer were employed to allow for the strong tropical water vapor absorption and emission. Cirrus cells that developed on one morning, independent of other clouds, had measured infrared emittances varying from <0.1 to 1.0.

  6. Adiabatic Tip-Plasmon Focusing for Nano-Raman Spectroscopy. ...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Adiabatic Tip-Plasmon Focusing for Nano-Raman Spectroscopy. Adiabatic Tip-Plasmon Focusing for Nano-Raman Spectroscopy. Abstract: True nanoscale optical spectroscopy requires the...

  7. Site-Specific Raman Spectroscopy and Chemical Dynamics of Nanoscale...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Raman Spectroscopy and Chemical Dynamics of Nanoscale Interstitial Systems. Site-Specific Raman Spectroscopy and Chemical Dynamics of Nanoscale Interstitial Systems. Abstract:...

  8. FIRST PRINCIPLES MODELING FOR LIDAR SENSING OF COMPLEX ICE SURFACES

    E-Print Network [OSTI]

    Kerekes, John

    FIRST PRINCIPLES MODELING FOR LIDAR SENSING OF COMPLEX ICE SURFACES J. Kerekes, A. Goodenough, S of monitoring the dynamics and mass balance of glaciers, ice caps, and ice sheets. However, it is also known that ice surfaces can have complex 3-dimensional structure, which can challenge their accurate retrieval

  9. Lidar on the Phoenix mission to Mars James Whiteway,1

    E-Print Network [OSTI]

    Duck, Thomas J.

    Cameron Dickinson,1 Leonce Komguem,1 and Clive Cook1 Received 30 August 2007; revised 9 March 2008 of backscattered laser light from airborne dust and clouds. These observations will be coordinated with solar, and C. Cook (2008), Lidar on the Phoenix mission to Mars, J. Geophys. Res., 113, E00A08, doi:10

  10. absorption lidar performance: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    absorption lidar performance First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Development of a...

  11. absorption lidar sensitivity: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    absorption lidar sensitivity First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Development of a...

  12. absorption lidar system: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    absorption lidar system First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Development of a differential...

  13. INTEGRATED LIDAR & PHOTOGRAMMETRIC DOCUMENTATION OF THE RED GULCH DINOSAUR

    E-Print Network [OSTI]

    Falkingham, Peter

    101 INTEGRATED LIDAR & PHOTOGRAMMETRIC DOCUMENTATION OF THE RED GULCH DINOSAUR TRACKSITE (WYOMING Resource Technology Section, National Operations Center, Bu- reau of Land Management, Bldg. 50 Denver, CO of successful schemes is testament to the advances made in attitudes and approaches to fossil site management

  14. Quantum Nature of Plasmon-Enhanced Raman Scattering

    E-Print Network [OSTI]

    Kusch, Patryk; Lehmann, Christian; Müller, Niclas S; Wasserroth, Sören; Oikonomou, Antonios; Clark, Nicholas; Vijayaraghavan, Aravind; Reich, Stephanie

    2015-01-01T23:59:59.000Z

    We report plasmon-enhanced Raman scattering in graphene coupled to a single plasmonic hotspot measured as a function of laser energy. The enhancement profiles of the G peak show strong enhancement (up to $10^5$) and ultra-narrow resonances (15 meV) that are induced by the localized surface plasmon of a gold nanodimer. We observe the evolution of defect-mode scattering in a defect-free graphene lattice in resonance with the plasmon. We propose a quantum theory of plasmon-enhanced Raman scattering, where the plasmon forms an integral part of the excitation process. Quantum interferences between scattering channels explain the experimentally observed resonance profiles, in particular, the marked difference in enhancement factors for incoming and outgoing resonance and the appearance of the defect-type modes.

  15. Airborne Multiwavelength High-Spectral-Resolution Lidar (HSRL-2) Observations During TCAP 2012: Vertical Proles of Optical and Microphysical Properties of a Smoke/Urban Haze Plume Over the Northeastern Coast of the US

    SciTech Connect (OSTI)

    Muller, Detlef; Hostetler, Chris A.; Ferrare, R. A.; Burton, S. P.; Chemyakin, Eduard; Kolgotin, A.; Hair, John; Cook, A. L.; Harper, David; Rogers, R. R.; Hare, Rich; Cleckner, Craig; Obland, Michael; Tomlinson, Jason M.; Berg, Larry K.; Schmid, Beat

    2014-10-10T23:59:59.000Z

    We present rst measurements with the rst airborne multiwavelength High-Spectral Resolution Lidar (HSRL-2), developed by NASA Langley Research Center. The instrument was operated during the Department of Energy (DOE) Two-Column Aerosol Project (TCAP) in July 2012. We observed out ow of urban haze and fresh biomass burning smoke from the East Coast of the US out over the West Atlantic Ocean. Lidar ratios at 355 and 532 nm were ... sr indicating moderately absorbing aerosols. Extinctionrelated Angstrom exponents were 1.5{2 pointing at comparably small particles. Our novel automated, unsupervised data inversion algorithm retrieves particle e*ective radii of approximately 0.2 *m, which is in agreement with the large Angstrom exponents. We nd reasonable agreement to particle size parameters obtained from situ measurements carried out with the DOE G-1 aircraft that ew during the lidar observations.

  16. Raman-induced limits to efficient squeezing in optical fibers

    E-Print Network [OSTI]

    Ruifang Dong; Joel Heersink; Joel F. Corney; Peter D. Drummond; Ulrik L. Andersen; Gerd Leuchs

    2007-09-14T23:59:59.000Z

    We report new experiments on polarization squeezing using ultrashort photonic pulses in a single pass of a birefringent fiber. We measure what is to our knowledge a record squeezing of -6.8 +/- 0.3 dB in optical fibers which when corrected for linear losses is -10.4 +/- 0.8 dB. The measured polarization squeezing as a function of optical pulse energy, which spans a wide range from 3.5-178.8 pJ, shows a very good agreement with the quantum simulations and for the first time we see the experimental proof that Raman effects limit and reduce squeezing at high pulse energy.

  17. Raman fiber optic probe assembly for use in hostile environments

    DOE Patents [OSTI]

    Schmucker, John E. (Hurt, VA); Falk, Jon C. (Pittsburgh, PA); Archer, William B. (Bethel Park, PA); Blasi, Raymond J. (Harrison City, PA)

    2000-01-01T23:59:59.000Z

    This invention provides a device for Raman spectroscopic measurement of composition and concentrations in a hostile environment by the use of a first fiber optic as a means of directing high intensity monochromatic light from a laser to the hostile environment and a second fiber optic to receive the lower intensity scattered light for transmittal to a monochromator for analysis. To avoid damage to the fiber optics, they are protected from the hostile environment. A preferred embodiment of the Raman fiber optic probe is able to obtain Raman spectra of corrosive gases and solutions at temperatures up to 600.degree. F. and pressures up to 2000 psi. The incident exciting fiber optic cable makes an angle of substantially 90.degree. with the collecting fiber optic cable. This 90.degree. geometry minimizes the Rayleigh scattering signal picked up by the collecting fiber, because the intensity of Rayleigh scattering is lowest in the direction perpendicular to the beam path of the exciting light and therefore a 90.degree. scattering geometry optimizes the signal to noise ratio.

  18. Magnetic sublevel specific stimulated Raman pumping of molecular H2 Sarah Cureton-Chinn, Peter B. Kelly, and Matthew P. Augustinea)

    E-Print Network [OSTI]

    Augustine, Mathew P.

    Magnetic sublevel specific stimulated Raman pumping of molecular H2 Sarah Cureton-Chinn, Peter B of the X 1 g ,v 1,J 1 state of molecular H2 using stimulated Raman pumping with circularly polarized light for the v 0 and v 1 states combined with their depolarization ratios measured as a function of pumping light

  19. Raman pulse duration effect in gravity gradiometers composed of two atom interferometers

    E-Print Network [OSTI]

    Shao, Cheng-Gang; Zhou, Min-Kang; Tan, Yu-Jie; Chen, Le-Le; Luo, Jun; Kun-Hu, Zhong

    2015-01-01T23:59:59.000Z

    We investigated the Raman pulse duration effect in a gravity gradiometer with two atom interferometers. Since the two atom clouds in the gradiometer experience different gravitational fields, it is hard to compensate the Doppler shifts of the two clouds simultaneously by chirping the frequency of a common Raman laser, which leads to an appreciable phase shift. When applied to an experiment measuring the Newtonian gravitational constant G, the effect contributes to a systematic offset as large as -49ppm in Nature 510, 518 (2014). Thus an underestimated value of G measured by atom interferometers can be partly explained due to this effect.

  20. High-resolution inverse Raman and resonant-wave-mixing spectroscopy

    SciTech Connect (OSTI)

    Rahn, L.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01T23:59:59.000Z

    These research activities consist of high-resolution inverse Raman spectroscopy (IRS) and resonant wave-mixing spectroscopy to support the development of nonlinear-optical techniques for temperature and concentration measurements in combustion research. Objectives of this work include development of spectral models of important molecular species needed to perform coherent anti-Stokes Raman spectroscopy (CARS) measurements and the investigation of new nonlinear-optical processes as potential diagnostic techniques. Some of the techniques being investigated include frequency-degenerate and nearly frequency-degenerate resonant four-wave-mixing (DFWM and NDFWM), and resonant multi-wave mixing (RMWM).

  1. Structural Analysis of Southern Dixie Valley using LiDAR and...

    Open Energy Info (EERE)

    Structural Analysis of Southern Dixie Valley using LiDAR and Low-Sun-Angle Aerial Photography, NAS Fallon Geothermal Exploration Project, Dixie Valley, Nevada Jump to: navigation,...

  2. Noninvasive glucose sensing by transcutaneous Raman spectroscopy

    E-Print Network [OSTI]

    Shih, Wei-Chuan

    We present the development of a transcutaneous Raman spectroscopy system and analysis algorithm for noninvasive glucose sensing. The instrument and algorithm were tested in a preclinical study in which a dog model was used. ...

  3. The vibrational Raman spectrum of CS?

    E-Print Network [OSTI]

    Ballard, Harold Noble

    1950-01-01T23:59:59.000Z

    THE VIBRATIONAL RAMAN SPECTRUM OF CSp A Thesis By HAROLD NOBLE BALLARD Approved as to style and content by Chairman o| Committee THE VIBRATIONAL RAMAN SPECTRUM OF CS2 HAROLD NOBLE BALLARD A Thesis Suhmitted to the Graduate School... in the procurement of necessary equipment. SECTION I: INTRODUCTION. SECTION II: CLASSICAL THEORY OF RAHAM SCATTERING . SECTION III: THEORY OF NORMAL VIBRATIONS AND VIBRATIONAL WAVE EQUATIONS. A, Morsel Vibrations B. Vibrational Wave Eqnation and lhergy Levels...

  4. Tracking Honey Bees Using LIDAR (Light Detection and Ranging) Technology

    SciTech Connect (OSTI)

    BENDER, SUSAN FAE ANN; RODACY, PHILIP J.; SCHMITT, RANDAL L.; HARGIS JR., PHILIP J.; JOHNSON, MARK S.; KLARKOWSKI, JAMES R.; MAGEE, GLEN I.; BENDER, GARY LEE

    2003-01-01T23:59:59.000Z

    The Defense Advanced Research Projects Agency (DARPA) has recognized that biological and chemical toxins are a real and growing threat to troops, civilians, and the ecosystem. The Explosives Components Facility at Sandia National Laboratories (SNL) has been working with the University of Montana, the Southwest Research Institute, and other agencies to evaluate the feasibility of directing honeybees to specific targets, and for environmental sampling of biological and chemical ''agents of harm''. Recent work has focused on finding and locating buried landmines and unexploded ordnance (UXO). Tests have demonstrated that honeybees can be trained to efficiently and accurately locate explosive signatures in the environment. However, it is difficult to visually track the bees and determine precisely where the targets are located. Video equipment is not practical due to its limited resolution and range. In addition, it is often unsafe to install such equipment in a field. A technology is needed to provide investigators with the standoff capability to track bees and accurately map the location of the suspected targets. This report documents Light Detection and Ranging (LIDAR) tests that were performed by SNL. These tests have shown that a LIDAR system can be used to track honeybees. The LIDAR system can provide both the range and coordinates of the target so that the location of buried munitions can be accurately mapped for subsequent removal.

  5. ARM: ARSCL: cloud base height from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Coulter, Richard; Widener, Kevin; Bharadwaj, Nitin; Johnson, Karen; Martin, Timothy

    ARSCL: cloud base height from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

  6. DOE/SC-ARM/TR-100 Raman Lidar Profiles Best Estimate Value-Added Product Technical Report

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration wouldDECOMPOSITION OF CALCIUMCOSTDOENuclear1382 THEDOE0-354-1502225 The780

  7. Tunable infrared source employing Raman mixing

    DOE Patents [OSTI]

    Byer, Robert L. (Stanford, CA); Herbst, Richard L. (Menlo Park, CA)

    1980-01-01T23:59:59.000Z

    A tunable source of infrared radiation is obtained by irradiating an assemblage of Raman active gaseous atoms or molecules with a high intensity pumping beam of coherent radiation at a pump frequency .omega..sub.p to stimulate the generation of Stokes wave energy at a Stokes frequency .omega..sub.s and to stimulate the Raman resonant mode at the Raman mode frequency .omega..sub.R within the irradiated assemblage where the pump frequency .omega..sub.p minus the Stokes frequency .omega..sub.s is equal to the Raman mode frequency .omega..sub.R. The stimulated assemblage is irradiated with a tunable source of coherent radiation at a frequency .omega..sub.i to generate the output infrared radiation of the frequency .omega..sub.0 which is related to the Raman mode frequency .omega..sub.R and the input wave .omega..sub.i by the relation .omega..sub.0 =.omega..sub.i .+-..omega..sub.R. In one embodiment the interaction between the pump wave energy .omega..sub.p and the tunable input wave energy .omega..sub.i is collinear and the ratio of the phase velocity mismatch factor .DELTA.k to the electric field exponential gain coefficient T is within the range of 0.1 to 5. In another embodiment the pump wave energy .omega..sub.p and the tunable input wave energy .omega..sub.i have velocity vectors k.sub.p and k.sub.i which cross at an angle to each other to compensate for phase velocity mismatches in the medium. In another embodiment, the Stokes wave energy .omega..sub.s is generated by pump energy .omega..sub.p in a first Raman cell and .omega..sub.s, .omega..sub.i and .omega..sub.p are combined in a second Raman mixing cell to produce the output at .omega..sub.i.

  8. URBAN AEROSOLS SURVEY USING LIDAR AND NUMERICAL MODEL S. GEFFROY1

    E-Print Network [OSTI]

    Boyer, Edmond

    URBAN AEROSOLS SURVEY USING LIDAR AND NUMERICAL MODEL S. GEFFROY1 , L. SOULHAC2 , E. FREJAFON3 , R technologique ALATA BP2, F-60550 Verneuil-en-Halatte, France. Keywords: LIDAR, URBAN AEROSOLS, MODEL, IMPACT SURVEY. INTRODUCTION The impact of particulate matters and aerosols on environment and on radiative

  9. A technique for autocalibration of cloud lidar EWAN J. O'CONNOR

    E-Print Network [OSTI]

    Hogan, Robin

    The lidar return backscattered from clouds is a power- ful tool in the remote sensing of clouds (e.g. Platt signal from the atmosphere (e.g. Fernald et al., 1972; Platt, 1973). To detect molecular backscatter. The integrated backscatter is equal to the reciprocal of twice the lidar ra- tio (Platt, 1979

  10. Geospatial revolution and remote sensing LiDAR in Mesoamerican archaeology

    E-Print Network [OSTI]

    Weishampel, John F.

    #12;Geospatial revolution and remote sensing LiDAR in Mesoamerican archaeology Arlen F. Chasea,1. The impor- tance of this geospatial innovation is demonstrated with newly acquired LiDAR data from in the remote geospatial imaging of cultural landscapes, including ancient communities and their anthropogenic

  11. BUILDING ROOF SEGMENTATION AND RECONSTRUCTION FROM LIDAR POINT CLOUDS USING CLUSTERING TECHNIQUES

    E-Print Network [OSTI]

    Shan, Jie

    BUILDING ROOF SEGMENTATION AND RECONSTRUCTION FROM LIDAR POINT CLOUDS USING CLUSTERING TECHNIQUES presents an approach to creating a polyhedral model of building roof from LiDAR point clouds using. The normal vectors are then clustered together to determine the principal directions of the roof planes

  12. 3-D tomographic imaging of ocean mines from real and simulated lidar returns

    E-Print Network [OSTI]

    Singer, Andrew C

    3-D tomographic imaging of ocean mines from real and simulated lidar returns Nail C¸adalli, Peter J of underwater objects, where the trans- mitted laser beam can penetrate the air-water interface and illuminate by using an accurate statistical model that incorporates multiple scattering. Keywords: lidar, ocean optics

  13. Complete Residential Urban Area Reconstruction from Dense Aerial LiDAR Point Clouds

    E-Print Network [OSTI]

    Shahabi, Cyrus

    Complete Residential Urban Area Reconstruction from Dense Aerial LiDAR Point Clouds Qian-Yi Zhou area modeling and residential area modeling is that the latter usually con- tains rich vegetation. Thus representing the 3D urban reality of residential areas. Keywords: urban modeling, LiDAR, residential area

  14. Modeling Residential Urban Areas from Dense Aerial LiDAR Point Clouds

    E-Print Network [OSTI]

    Shahabi, Cyrus

    Modeling Residential Urban Areas from Dense Aerial LiDAR Point Clouds Qian-Yi Zhou and Ulrich models for residential areas from aerial LiDAR scans. The key differ- ence between downtown area modeling and residential area modeling is that the latter usually contains rich vegetation. Thus, we propose a robust

  15. Use of a lidar forward model for global comparisons of cloud fraction

    E-Print Network [OSTI]

    Hogan, Robin

    555 Use of a lidar forward model for global comparisons of cloud fraction between the ICESat lidar in extinction-to-backscatter ratio and effective radius affect the forward modeled mean cloud fraction by no more than 10%. 1. Introduction Clouds play a major role in the Earth's radiation budget and predictions

  16. Determination of the paradihlorobenzene and paradibromobenzene solid solutions nanoparticles structure via Raman spectra

    E-Print Network [OSTI]

    Korshunov, M A

    2012-01-01T23:59:59.000Z

    We measured the small frequencies Raman spectrum of the paradihlorobenzene and paradihlorobenzene solid solution nanoparticles with the size about 100 nanometers. Values of frequencies of lines decrease. The size of nanoparticles was determined by the electronic microscope. Calculations of nanoparticles structure were done using the method of molecular dynamics and histograms of nanoparticles spectra were calculated via the Dyne's method. The result is that the Raman spectrum is the sum of spectra from the central part of the nanoparticle and superficial structures with smaller concentration of paradihlorobenzene.

  17. Theory of Two-Magnon Raman Scattering in Iron Pnictides and Chalcogenides

    SciTech Connect (OSTI)

    Chen, C. C.

    2011-08-15T23:59:59.000Z

    Although the parent iron-based pnictides and chalcogenides are itinerant antiferromagnets, the use of local moment picture to understand their magnetic properties is still widespread. We study magnetic Raman scattering from a local moment perspective for various quantum spin models proposed for this new class of superconductors. These models vary greatly in the level of magnetic frustration and show a vastly different two-magnon Raman response. Light scattering by two-magnon excitations thus provides a robust and independent measure of the underlying spin interactions. In accord with other recent experiments, our results indicate that the amount of magnetic frustration in these systems may be small.

  18. Investigation of the Thermal Decomposition of Triethylgallium Using in situ Raman Spectroscopy and DFT Calculations

    E-Print Network [OSTI]

    Anderson, Timothy J.

    (TEGa) were followed using in situ Raman spectroscopy measurements in an up-flow, cold-wall CVD reactor an design with ss beads to p ure 1. Schem asurements. dy, the gas p ectroscopy i h numerical ons, which w Ex

  19. Journal of Crystal Growth 288 (2006) 5356 Spatially resolved photoluminescence and Raman spectroscopy of

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    in a waveguide with a core consisting of GaAs/AlAs short superlattice (SSL) structure using quantum well spectroscopy measurements, where Raman spectra were collected at different depths of the SSL through probing the SSL layer cross-section. SSL-related phonon states were clearly observed for the lower part of the SSL

  20. ROTATIONAL AND VIBRATIONAL RAMAN SPECTROSCOPY FOR FLOW FROM AN UNDEREXPANDED JET NOZZLE

    E-Print Network [OSTI]

    Bayeh, Alexander

    2008-08-19T23:59:59.000Z

    will be carried out using roational-vibrational Raman line imaging through the axis of the jet exhaust. In this way measurements of the flow field under high pressure, temperature, and velocity can be made without disrupting it. Because of the increasing push...

  1. Nanohole-Enhanced Raman Scattering Alexandre G. Brolo,*, Erin Arctander, Reuven Gordon, Brian Leathem, and

    E-Print Network [OSTI]

    Brolo, Alexandre G.

    . SP excitations lead to spatial localization of the electromagnetic fields in nanometric regions close techniques for monitoring binding events in biological systems.9 Tradition- ally, an SPR measurement consists to the surface. This field localization, allied to the unique vibrational signature of the Raman scattering

  2. Absolute Raman matrix elements of graphene and graphite

    E-Print Network [OSTI]

    Reich, Stephanie

    Using sample substitution [Grimsditch et al., J. Raman Spectrosc. 10, 77 (1981)] we deconvolve the highly wavelength-dependent response of the spectrometer from the Raman spectra of graphene suspended on an SiO[subscript ...

  3. Real-time Raman system for in vivo disease diagnosis

    E-Print Network [OSTI]

    Motz, Jason T.

    Raman spectroscopy has been well established as a powerful in vitro method for studying biological tissue and diagnosing disease. The recent development of efficient, high-throughput, low-background optical fiber Raman ...

  4. Raman and surface-enhanced Raman study of asymmetrically substituted viologens

    SciTech Connect (OSTI)

    Lu, T.; Cotton, T.M.; Hurst, J.K.; Thompson, D.H.P.

    1988-12-01T23:59:59.000Z

    The normal Raman (NR), resonance Raman (RR), surface-enhanced Raman scattering (SERS), and surface-enhanced resonance Raman scattering (SERRS) spectra of the three redox forms of several asymmetric viologens, N-octyl-N'-methylviologen (C/sub 8/MV), N-dodecyl-N'-methylviologen (C/sub 12/MV), and N-hexadecyl-N'-methylviologen (C/sub 16/MV), have been characterized and compared with the corresponding spectra of the three redox forms of methylviologen (MV). It was observed that the substituents of the two N atoms of the viologen do not affect its overall symmetry. Only the Raman bands near 1200 cm/sup /minus/1/, containing major contributions from the N-alkyl stretching vibrations, are affected by the asymmetric substitution. The RR spectra of both the monomer and dimer forms of the cation radicals were obtained by varying the experimental conditions used in their preparation. As previously observed for MV, dimerization of the asymmetric viologen radicals produces splitting of certain RR bands. Resonance Raman spectra of the fully reduced viologens were also obtained and used to monitor the disproportionation reaction between the dication and fully reduced form of the viologen. Surface-enhanced Raman and SERRS spectra of the different asymmetric viologens were found to vary slightly due to changes in their adsorption behavior with increasing chain length of the alkyl substituent.

  5. Multistaged stokes injected Raman capillary waveguide amplifier

    DOE Patents [OSTI]

    Kurnit, Norman A. (Santa Fe, NM)

    1980-01-01T23:59:59.000Z

    A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

  6. Remote adjustable focus Raman spectroscopy probe

    DOE Patents [OSTI]

    Schmucker, John E. (Hurt, VA); Blasi, Raymond J. (Harrison City, PA); Archer, William B. (Bethel Park, PA)

    1999-01-01T23:59:59.000Z

    A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external probe. An environmental barrier including at least one window separates the probe from the point of interest. An optical tube is disposed adjacent to the environmental barrier and includes a long working length compound lens objective next to the window. A beam splitter and a mirror are at the other end. A mechanical means is used to translated the prove body in the X, Y, and Z directions resulting in a variable focus optical apparatus. Laser light is reflected by the beam splitter and directed toward the compound lens objective, then through the window and focused on the point of interest. Raman scattered light is then collected by the compound lens objective and directed through the beam splitter to a mirror. A device for analyzing the light, such as a monochrometer, is coupled to the mirror.

  7. Human brain cancer studied by resonance Raman spectroscopy

    E-Print Network [OSTI]

    Sun, Yi

    Human brain cancer studied by resonance Raman spectroscopy Yan Zhou Cheng-Hui Liu Yi Sun Yang Pu://biomedicaloptics.spiedigitallibrary.org/ on 11/16/2012 Terms of Use: http://spiedl.org/terms #12;Human brain cancer studied by resonance Raman of human brain tissues are examined using a confocal micro-Raman system with 532-nm excitation in vitro

  8. Vibrational Raman Spectroscopy of High-temperature Superconductors

    E-Print Network [OSTI]

    Nabben, Reinhard

    Vibrational Raman Spectroscopy of High-temperature Superconductors C. Thomsen and G. Kaczmarczyk-temperature Superconductors C. Thomsen and G. Kaczmarczyk Technical University of Berlin, Berlin, Germany 1 INTRODUCTION Raman after the discovery of high- critical-temperature Tc superconductors:2 while reports on Raman scattering

  9. ARM - Field Campaign - Aerosol Lidar Validation Experiment - ALIVE

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032)8Li (59AJ76)ARM2, 2006ObservationsInfraredgovCampaignsAerosol Lidar

  10. ARM - Field Campaign - M-PACE - Polarization Diversity Lidar (PDL)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa- Polarization Diversity Lidar (PDL) Campaign Links M-PACE Website ARM Data Discovery

  11. ARM - Field Campaign - M-PACE HSR Lidar

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa- Polarization Diversity Lidar (PDL) Campaign Links M-PACE Website ARM Data DiscoveryHSR

  12. Theory of Raman enhancement by two-dimensional materials: Applications for graphene-enhanced Raman spectroscopy

    E-Print Network [OSTI]

    Barros, E. B.

    We propose a third-order time-dependent perturbation theory approach to describe the chemical surface-enhanced Raman spectroscopy of molecules interacting with two-dimensional (2D) surfaces such as an ideal 2D metal and ...

  13. Raman laser with controllable suppression of parasitics

    DOE Patents [OSTI]

    George, E. Victor (Livermore, CA)

    1986-01-01T23:59:59.000Z

    Method and apparatus for switching energy out of a Raman laser optical cavity. Coherent radiation at both the pump and first Stokes wave frequencies are introduced into the optical cavity from the same direction, and a second Stokes wave is utilized to switch the energy out of the cavity.

  14. Stokes injected Raman capillary waveguide amplifier

    DOE Patents [OSTI]

    Kurnit, Norman A. (Santa Fe, NM)

    1980-01-01T23:59:59.000Z

    A device for producing stimulated Raman scattering of CO.sub.2 laser radiation by rotational states in a diatomic molecular gas utilizing a Stokes injection signal. The system utilizes a cryogenically cooled waveguide for extending focal interaction length. The waveguide, in conjunction with the Stokes injection signal, reduces required power density of the CO.sub.2 radiation below the breakdown threshold for the diatomic molecular gas. A Fresnel rhomb is employed to circularly polarize the Stokes injection signal and CO.sub.2 laser radiation in opposite circular directions. The device can be employed either as a regenerative oscillator utilizing optical cavity mirrors or as a single pass amplifier. Additionally, a plurality of Raman gain cells can be staged to increase output power magnitude. Also, in the regenerative oscillator embodiment, the Raman gain cell cavity length and CO.sub.2 cavity length can be matched to provide synchronism between mode locked CO.sub.2 pulses and pulses produced within the Raman gain cell.

  15. Combination ring cavity and backward Raman waveguide amplifier

    DOE Patents [OSTI]

    Kurnit, Norman A. (Santa Fe, NM)

    1983-01-01T23:59:59.000Z

    A combination regenerative ring and backward Raman waveguide amplifier and a combination regenerative ring oscillator and backward Raman waveguide amplifier which produce Raman amplification, pulse compression, and efficient energy extraction from the CO.sub.2 laser pump signal for conversion into a Stokes radiation signal. The ring cavity configuration allows the CO.sub.2 laser pump signal and Stokes signal to copropagate through the Raman waveguide amplifier. The backward Raman waveguide amplifier configuration extracts a major portion of the remaining energy from the CO.sub.2 laser pump signal for conversion to Stokes radiation. Additionally, the backward Raman amplifier configuration produces a Stokes radiation signal which has a high intensity and a short duration. Adjustment of the position of overlap of the Stokes signal and the CO.sub.2 laser pump signal in the backward Raman waveguide amplifiers alters the amount of pulse compression which can be achieved.

  16. Fully automatic calibration of LIDAR and video streams from a vehicle

    E-Print Network [OSTI]

    Bileschi, Stanley M.

    This work describes a fully automatic technique to calibrate a geometric mapping between lidar and video feeds on a mobile ground-based platform. This data association is a crucial first step for any multi-modal scene ...

  17. Studying Clouds and Aerosols with Lidar Depolarization Ratio and Backscatter Relationships

    E-Print Network [OSTI]

    Cho, Hyoun-Myoung

    2012-02-14T23:59:59.000Z

    comparison of mineral dust aerosol retrievals from two instruments, MODIS and CALIPSO lidar. And, we implement and evaluate a new mineral dust detection algorithm based on the analysis of thin dust radiative signature. In comparison, three commonly used...

  18. Accessing the Energy Department’s Lidar Buoy Data off Virginia Beach

    Broader source: Energy.gov [DOE]

    In December 2014, Pacific Northwest National Laboratory (PNNL) deployed the Energy Department’s floating lidar buoy off of Virginia Beach, Virginia, in less than 30 meters (m) of water,...

  19. The Daytime Mixed Layer Observed by Radiosonde, Profiler, and LIDAR during MILAGRO

    SciTech Connect (OSTI)

    Shaw, William J.; Pekour, Mikhail S.; Coulter, Richard L.; Martin, Tim J.; Walters, Justin

    2007-10-19T23:59:59.000Z

    During the MILAGRO campaign centered in the Mexico City area, Pacific Northwest National Laboratory (PNNL) and Argonne National Laboratory (ANL) operated several atmospheric profiling systems at Veracruz and at two locations on the Central Mexican Plateau in the region around Mexico City. These systems included radiosondes, wind profilers, a sodar, and an aerosol backscatter lidar. An additional wind profiler was operated by the University of Alabama in Huntsville (UAH) at the Mexican Petroleum Institue (IMP) near the center of Mexico City. Because of the opportunity afforded by collocation of profilers, radiosondes, and a lidar, and because of the importance of boundary layer depth on aerosol properties, we have carried out a comparison of mixed layer depth as determined independently from these three types of measurement systems during the campaign. We have then used results of this comparison and additional measurements to develop a detailed description of the daily structure and evolution of the boundary layer on the Central Mexican Plateau during MILAGRO. Our analysis indicates that the profilers were more consistently successful in establishing the mixing layer depth during the daytime. The boundary layer growth was similar at the three locations, although the mixing layer tended to be slightly deeper in the afternoon in central Mexico City. The sodar showed that convection began about an hour after sunrise. Maximum daily mixed layer depths always reached 2000 m AGL and frequently extended to 4000 m. The rate and variability of mixing layer growth was essentially the same as that observed during the IMADA-AVER campaign in the same season in 1997. This growth did not seem to be related to whether deep convection was reported on a given day. Wind speeds within the boundary layer exhibited a daily low-altitude maximum in the late afternoon with lighter winds aloft, consistent with previous reports of diurnal regional circulations. Norte events, which produced high winds at Veracruz, did not appreciably modulate the winds on the plateau. Finally, despite the typically dry conditions at the surface, radiosonde profiles showed that relative humidity often exceeded 50% in the early morning and in the upper part of the boundary layer.

  20. Raman-based system for DNA sequencing-mapping and other separations

    DOE Patents [OSTI]

    Vo-Dinh, Tuan (Knoxville, TN)

    1994-01-01T23:59:59.000Z

    DNA sequencing and mapping are performed by using a Raman spectrometer with a surface enhanced Raman scattering (SERS) substrate to enhance the Raman signal. A SERS label is attached to a DNA fragment and then analyzed with the Raman spectrometer to identify the DNA fragment according to characteristics of the Raman spectrum generated.

  1. Assessing Available Woody Plant Biomass on Rangelands with Lidar and Multispectral Remote Sensing

    E-Print Network [OSTI]

    Ku, Nian-Wei

    2012-07-16T23:59:59.000Z

    ASSESSING AVAILABLE WOODY PLANT BIOMASS ON RANGELANDS WITH LIDAR AND MULTISPECTRAL REMOTE SENSING A Thesis by NIAN-WEI KU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... ASSESSING AVAILABLE WOODY PLANT BIOMASS ON RANGELANDS WITH LIDAR AND MULTISPECTRAL REMOTE SENSING A Thesis by NIAN-WEI KU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements...

  2. Algorithms and Software Tools for Extracting Coastal Morphological Information from Airborne LiDAR Data

    E-Print Network [OSTI]

    Gao, Yige

    2010-07-14T23:59:59.000Z

    ALGORITHMS AND SOFTWARE TOOLS FOR EXTRACTING COASTAL MORPHOLOGICAL INFORMATION FROM AIRBORNE LiDAR DATA A Thesis by YIGE GAO Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 2009 Major Subject: Geography ALGORITHMS AND SOFTWARE TOOLS FOR EXTRACTING COASTAL MORPHOLOGICAL INFORMATION FROM AIRBORNE LiDAR DATA A Thesis by YIGE GAO...

  3. Retrieval of Urban Boundary Layer Structures from Doppler Lidar Data. Part I: Accuracy Assessment

    SciTech Connect (OSTI)

    Xia, Quanxin; Lin, Ching Long; Calhoun, Ron; Newsom, Rob K.

    2008-01-01T23:59:59.000Z

    Two coherent Doppler lidars from the US Army Research Laboratory (ARL) and Arizona State University (ASU) were deployed in the Joint Urban 2003 atmospheric dispersion field experiment (JU2003) held in Oklahoma City. The dual lidar data are used to evaluate the accuracy of the four-dimensional variational data assimilation (4DVAR) method and identify the coherent flow structures in the urban boundary layer. The objectives of the study are three-fold. The first objective is to examine the effect of eddy viscosity models on the quality of retrieved velocity data. The second objective is to determine the fidelity of single-lidar 4DVAR and evaluate the difference between single- and dual-lidar retrievals. The third objective is to correlate the retrieved flow structures with the ground building data. It is found that the approach of treating eddy viscosity as part of control variables yields better results than the approach of prescribing viscosity. The ARL single-lidar 4DVAR is able to retrieve radial velocity fields with an accuracy of 98% in the along-beam direction and 80-90% in the cross-beam direction. For the dual-lidar 4DVAR, the accuracy of retrieved radial velocity in the ARL cross-beam direction improves to 90-94%. By using the dual-lidar retrieved data as a reference, the single-lidar 4DVAR is able to recover fluctuating velocity fields with 70-80% accuracy in the along-beam direction and 60-70% accuracy in the cross-beam direction. Large-scale convective roll structures are found in the vicinity of downtown airpark and parks. Vortical structures are identified near the business district. Strong updrafts and downdrafts are also found above a cluster of restaurants.

  4. Detection of surface carbon and hydrocarbons in hot spot regions of niobium superconducting rf cavities by Raman spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cao, C.; Ford, D.; Bishnoi, S.; Proslier, T.; Albee, B.; Hommerding, E.; Korczakowski, A.; Cooley, L.; Ciovati, G.; Zasadzinski, J. F.

    2013-06-01T23:59:59.000Z

    Raman microscopy/spectroscopy measurements are presented on high purity niobium (Nb) samples, including pieces from hot spot regions of a tested superconducting rf cavity that exhibit a high density of etch pits. Measured spectra are compared with density functional theory calculations of Raman-active, vibrational modes of possible surface Nb-O and Nb-H complexes. The Raman spectra inside particularly rough pits in all Nb samples show clear differences from surrounding areas, exhibiting enhanced intensity and sharp peaks. While some of the sharp peaks are consistent with calculated NbH and NbH2 modes, there is better overall agreement with C-H modes in chain-type hydrocarbons. Other spectra reveal two broader peaks attributed to amorphous carbon. Niobium foils annealed to >2000°C in high vacuum develop identical Raman peaks when subjected to cold working. Regions with enhanced C and O have also been found by SEM/EDX spectroscopy in the hot spot samples and cold-worked foils, corroborating the Raman results. Such regions with high concentrations of impurities are expected to suppress the local superconductivity and this may explain the correlation between hot spots in superconducting rf (SRF) cavities and the observation of a high density of surface pits. The origin of localized high carbon and hydrocarbon regions is unclear at present but it is suggested that particular processing steps in SRF cavity fabrication may be responsible.

  5. State detection using coherent Raman repumping and two-color Raman transfers

    SciTech Connect (OSTI)

    Chuah, Boon Leng; Lewty, Nicholas C.; Barrett, Murray D. [Center for Quantum Technologies and Department of Physics, National University of Singapore, 3 Science Drive 2, 117543 Singapore (Singapore)

    2011-07-15T23:59:59.000Z

    We demonstrate state detection based on coherent Raman repumping and a two-color Raman state transfer. The Raman coupling during detection selectively eliminates unwanted dark states in the fluorescence cycle without compromising the immunity of the desired dark state to off-resonant scattering. We demonstrate this technique using {sup 137}Ba{sup +} where a combination of Raman coupling and optical pumping leaves the metastable state, D{sub 3/2} |F''=3,m{sub F}{sup ''}=3>, optically dark and immune to off-resonant scattering. All other states are strongly coupled to the upper P{sub 1/2} levels. We achieve a single-shot state-detection efficiency of 89.6(3)% in a 1-ms integration time, limited almost entirely by technical imperfections. Shelving to |F{sup ''}=3,m{sub F}{sup ''}=3> before detection is performed via a two-color Raman transfer with a fidelity of 1.00(3).

  6. Nanosensors based on functionalized nanoparticles and surface enhanced raman scattering

    DOE Patents [OSTI]

    Talley, Chad E. (Brentwood, CA); Huser, Thomas R. (Livermore, CA); Hollars, Christopher W. (Brentwood, CA); Lane, Stephen M. (Oakland, CA); Satcher, Jr., Joe H. (Patterson, CA); Hart, Bradley R. (Brentwood, CA); Laurence, Ted A. (Livermore, CA)

    2007-11-27T23:59:59.000Z

    Surface-Enhanced Raman Spectroscopy (SERS) is a vibrational spectroscopic technique that utilizes metal surfaces to provide enhanced signals of several orders of magnitude. When molecules of interest are attached to designed metal nanoparticles, a SERS signal is attainable with single molecule detection limits. This provides an ultrasensitive means of detecting the presence of molecules. By using selective chemistries, metal nanoparticles can be functionalized to provide a unique signal upon analyte binding. Moreover, by using measurement techniques, such as, ratiometric received SERS spectra, such metal nanoparticles can be used to monitor dynamic processes in addition to static binding events. Accordingly, such nanoparticles can be used as nanosensors for a wide range of chemicals in fluid, gaseous and solid form, environmental sensors for pH, ion concentration, temperature, etc., and biological sensors for proteins, DNA, RNA, etc.

  7. Linear optics, Raman scattering, and spin noise spectroscopy

    E-Print Network [OSTI]

    Glazov, M M

    2015-01-01T23:59:59.000Z

    Spin noise spectroscopy (SNS) is a new method for studying magnetic resonance and spin dynamics based on measuring the Faraday rotation noise. In strong contrast with methods of nonlinear optics, the spectroscopy of spin noise is considered to be essentially nonperturbative. Presently, however, it became clear that the SNS, as an optical technique, demonstrates properties lying far beyond the bounds of conventional linear optics. Specifically, the SNS shows dependence of the signal on the light power density, makes it possible to penetrate inside an inhomogeneously broadened absorption band and to determine its homogeneous width, allows one to realize an effective pump-probe spectroscopy without any optical nonlinearity, etc. This may seem especially puzzling when taken into account that SNS can be considered just as a version of Raman spectroscopy, which is known to be deprived of such abilities. In this paper, we clarify this apparent inconsistency.

  8. UV-Photoreflectance and Raman Characterization of Strain Relaxation in Si on Silicon-Germanium Films

    SciTech Connect (OSTI)

    Current, Michael [Current Scientific, 1729 Comstock Way, San Jose, CA 95124 (United States); Chism, Will [Xitronix Corporation, 106 East Sixth Street, Ninth Floor, Austin TX, 78701 (United States); Yoo, Woo Sik [WaferMasters, Inc., 246 East Gist Road, San Jose, CA 95112 (United States); Vartanian, Victor [International Sematech Manufacturing Initiative, 257 Fuller Road, Suite 2200, Albany NY 12203 (United States)

    2011-11-10T23:59:59.000Z

    Photoreflectance (PR), using a uv (374 nm) diode laser probe beam, and Raman spectroscopy, using a multi-wavelength Ar{sup +} laser coupled to a high-resolution multi-wavelength spectrometer, were used to characterize the strain relaxation of Si top layers grown on a graded and relaxed SiGe buffer stack with a final Ge concentration of 20%. The Si top layer thicknesses ranged from 1.6 to 18 nm. Considerable radial variation in the strain relaxation was seen in all sampled wafers, highlighting the need for rapid, local strain characterization. Strong correlation between shift in the Si layer dielectric response, measured by uv-PR, and the Si top layer strain, measured by Raman, is reported.

  9. Manipulation of the Raman process via incoherent pump, tunable intensity, and phase control

    E-Print Network [OSTI]

    Wang, Li-Gang; Qamar, Sajid; Zhu, Shi-Yao; Zubairy, M. Suhail

    2008-01-01T23:59:59.000Z

    We present a proposal to manipulate the Raman process via incoherent pump, tunable intensity, and phase control of the driving fields. It is found that Raman absorptive peaks can become Raman gain peaks by controlling the incoherent pump...

  10. Raman and AFM study of gamma irradiated plastic bottle sheets

    SciTech Connect (OSTI)

    Ali, Yasir; Kumar, Vijay; Dhaliwal, A. S. [Department of Physics, Sant Longowal Institute of Engineering and Technology Longowal, Punjab-148106 (India); Sonkawade, R. G. [School of Physical Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow-226025 (India)

    2013-02-05T23:59:59.000Z

    In this investigation, the effects of gamma irradiation on the structural properties of plastic bottle sheet are studied. The Plastic sheets were exposed with 1.25MeV {sup 60}Co gamma rays source at various dose levels within the range from 0-670 kGy. The induced modifications were followed by micro-Raman and atomic force microscopy (AFM). The Raman spectrum shows the decrease in Raman intensity and formation of unsaturated bonds with an increase in the gamma dose. AFM image displays rough surface morphology after irradiation. The detailed Raman analysis of plastic bottle sheets is presented here, and the results are correlated with the AFM observations.

  11. Raman Scattering at Plasmonic Junctions Shorted by Conductive...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    between line spectra and band spectra, can be assigned to shorting the junction plasmon through molecular conductive bridges. This is demonstrated through Raman trajectories...

  12. Inelastic neutron scattering, Raman and DFT investigations of...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Inelastic neutron scattering, Raman and DFT investigations of the adsorption of phenanthrenequinone on onion-like carbon Daniela M. Anjos a , Alexander I. Kolesnikov a , Zili Wu a...

  13. Combining Raman Microprobe and XPS to Study High Temperature...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    spectroscopy. Citation: Windisch CF, Jr, CH Henager, MH Engelhard, and WD Bennett.2011."Combining Raman Microprobe and XPS to Study High Temperature Oxidation of...

  14. Raman and XPS characterization of fuel-cladding interactions...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    MOX fuel mixtures. Citation: Windisch CF, Jr, CH Henager, Jr, MH Engelhard, and WD Bennett.2009."Raman and XPS characterization of fuel-cladding interactions using miniature...

  15. Solution-based characterization of surface-enhanced Raman response of single scattering centers

    SciTech Connect (OSTI)

    Laurence, T A; Talley, C; Schwartzberg, A; Braun, G; Moskovits, M; Reich, N; Huser, T

    2008-03-06T23:59:59.000Z

    We demonstrate the rapid optical characterization of large numbers of individual metal nanoparticles freely diffusing in colloidal solution by confocal laser spectroscopy. We find that hollow gold nanospheres and solid silver nanoparticles linked with a bifunctional ligand, both designed nanostructures, exhibit significantly higher monodispersity in their Rayleigh and Raman scattering response than randomly aggregated gold and silver nanoparticles. We show that measurements of rotational diffusion timescales allow sizing of particles significantly more reliably than can be obtained using translational diffusion timescales.

  16. Evaluation of tropospheric water vapor profiling using eye-safe, infrared differential absorption lidar

    SciTech Connect (OSTI)

    Rye, B.J. [Colorado Univ., Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences]|[National Oceanic and Atmospheric Administration, Boulder, CO (United States). Environmental Technology Lab.; Machol, J.L.; Grund, C.J.; Hardesty, R.M. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Environmental Technology Lab.

    1996-05-14T23:59:59.000Z

    Continuous, high quality profiles of water vapor, free of systematic bias, and of moderate temporal and spatial resolution are fundamental to the success of the ARM CART program. In addition, these should be acquired over long periods at low operational and maintenance cost. The development and verification of realistic climate model parameterizations for clouds and net radiation balance, and the correction of other CART site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. To date, application of profiles have been limited by vertical resolution and uniqueness and high operating cost, or diminished daytime performance, lack of eye-safety, and high maintenance cost. Recent developments in infrared laser and detector technology make possible compact IR differential absorption lidar (DIAL) systems at eye-safe wavelengths. In the studies reported here, we develop DIAL system performance models and examine the potential of solving some of the shortcomings of previous methods using parameters representative of current technologies. These simulations are also applied to determine the strengths and weaknesses unique to the DIAL method for this application.

  17. Water O?H Stretching Raman Signature for Strong Acid Monitoring via Multivariate Analysis

    SciTech Connect (OSTI)

    Casella, Amanda J.; Levitskaia, Tatiana G.; Peterson, James M.; Bryan, Samuel A.

    2013-04-16T23:59:59.000Z

    Spectroscopic techniques have been applied extensively for quantification and analysis of solution compositions. In addition to static measurements, these techniques have been implemented in flow systems providing real-time solution information. A distinct need exists for information regarding acid concentration as it affects extraction efficiency and selectivity of many separation processes. Despite of the seeming simplicity of the problem, no practical solution has been offered yet particularly for the large-scale schemes involving toxic streams such as highly radioactive nuclear wastes. Classic potentiometric technique is not amiable for on-line measurements in nuclear fuel reprocessing due to requirements of frequent calibration/maintenance and poor long-term stability in the aggressive chemical and radiation environments. In this work, the potential of using Raman spectroscopic measurements for on-line monitoring of strong acid concentration in the solutions relevant to the dissolved used fuel was investigated. The Raman water signature was monitored and recorded for nitric and hydrochloric acid solution systems of systematically varied chemical composition, ionic strength, and temperature. The generated Raman spectroscopic database was used to develop predictive chemometric models for the quantification of the acid concentration (H+), neodymium concentration (Nd3+), nitrate concentration (NO3-), density, and ionic strength. This approach was validated using a flow solvent extraction system.

  18. Crystallinity and compositional changes in carbonated apatites: Evidence from {sup 31}P solid-state NMR, Raman, and AFM analysis

    SciTech Connect (OSTI)

    McElderry, John-David P.; Zhu, Peizhi [Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Mroue, Kamal H. [Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Xu, Jiadi [Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Pavan, Barbara [Department of Chemistry and Science of Advanced Materials Program, Central Michigan University, Mt. Pleasant, MI 48859 (United States); Fang, Ming [Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Zhao, Guisheng; McNerny, Erin; Kohn, David H.; Franceschi, Renny T. [School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Holl, Mark M.Banaszak [Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Tecklenburg, Mary M.J., E-mail: mary.tecklenburg@cmich.edu [Department of Chemistry and Science of Advanced Materials Program, Central Michigan University, Mt. Pleasant, MI 48859 (United States); Ramamoorthy, Ayyalusamy [Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Morris, Michael D. [Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States)

    2013-10-15T23:59:59.000Z

    Solid-state (magic-angle spinning) NMR spectroscopy is a useful tool for obtaining structural information on bone organic and mineral components and synthetic model minerals at the atomic-level. Raman and {sup 31}P NMR spectral parameters were investigated in a series of synthetic B-type carbonated apatites (CAps). Inverse {sup 31}P NMR linewidth and inverse Raman PO{sub 4}{sup 3?}?{sub 1} bandwidth were both correlated with powder XRD c-axis crystallinity over the 0.3–10.3 wt% CO{sub 3}{sup 2?} range investigated. Comparison with bone powder crystallinities showed agreement with values predicted by NMR and Raman calibration curves. Carbonate content was divided into two domains by the {sup 31}P NMR chemical shift frequency and the Raman phosphate ?{sub 1} band position. These parameters remain stable except for an abrupt transition at 6.5 wt% carbonate, a composition which corresponds to an average of one carbonate per unit cell. This near-binary distribution of spectroscopic properties was also found in AFM-measured particle sizes and Ca/P molar ratios by elemental analysis. We propose that this transition differentiates between two charge-balancing ion-loss mechanisms as measured by Ca/P ratios. These results define a criterion for spectroscopic characterization of B-type carbonate substitution in apatitic minerals. - Graphical abstract: Carbonated apatite shows an abrupt change in spectral (NMR, Raman) and morphological (AFM) properties at a composition of about one carbonate substitution per unit cell. Display Omitted - Highlights: • Crystallinity (XRD), particle size (AFM) of carbonated apatites and bone mineral. • Linear relationships among crystallinity, {sup 31}P NMR and Raman inverse bandwidths. • Low and high carbonated apatites use different charge-balancing ion-loss mechanism.

  19. Clinical feasibility of Raman spectroscopy for quantitative blood glucose measurement

    E-Print Network [OSTI]

    Kong, Chae-Ryon

    2011-01-01T23:59:59.000Z

    Diabetes mellitus is a leading cause of morbidity and mortality worldwide, and close monitoring of blood glucose levels is crucial for its diagnosis and management. Currently, blood glucose monitoring is done by blood ...

  20. Electrochemical and Raman measurements on single-walled carbon nanotubes

    E-Print Network [OSTI]

    Nabben, Reinhard

    is essentially one-dimensional and is completely determined by its chirality, i.e., the way a graphitic plane appearing as appropri- ate candidates for supercapacitors [3], batteries [4] and actuators [5]. Ramang bond-stretching mode of graphite. In contrast to graphite, the experimental (HEM) structure

  1. Simple Doppler Wind Lidar adaptive observation experiments with 3D-Var and an ensemble Kalman filter in a global primitive equations model

    E-Print Network [OSTI]

    Maryland at College Park, University of

    the next few years, the first Doppler Wind Lidar (DWL) will be deployed in space by the European Space1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Simple Doppler Wind Lidar adaptive Experiments, we compare several adaptive observation strategies designed to subsample Doppler Wind Lidar (DWL

  2. Hydrogen Raman shifts in carbon nanotubes from molecular dynamics simulation

    E-Print Network [OSTI]

    Brenner, Donald W.

    Hydrogen Raman shifts in carbon nanotubes from molecular dynamics simulation S.J.V. Frankland *, D hydrogen in individual single-shell carbon nanotubes and nanotube ropes using a semiclassical model. The calculations predict that isolated hydrogen molecules inside of nanotubes have a Raman frequency that increases

  3. Raman Scattering through a quantum-critical point

    E-Print Network [OSTI]

    Freericks, Jim

    spectral weight with underdoping. J. G. Naeini et al., PRB 1999 J. K. Freericks, Georgetown University, Raman scattering talk, 2001 M. Opel et al., PRB 2000 //( >> 0) k() qp scattering talk, 2001 #12;Experimental data for Kondo insulators · Nyhus et al, PRB 95 Raman scattering on Fe

  4. CLIENT : INDIAN ACADEMY OF SCIENCES C. V. RAMAN AVENUE,

    E-Print Network [OSTI]

    Joshi, Yogesh Moreshwar

    CLIENT : INDIAN ACADEMY OF SCIENCES C. V. RAMAN AVENUE, SADASHIVNAGAR, BANGALORE ­ 560080 TENDER : PROPOSED INTERIORS FOR CABIN CUM MEETING ROOM AT INDIAN ACADEMY OF SCIENCES, C V RAMAN AVENUE, BANGALORE COMPLEX, KAMARAJ ROAD, II CROSS, BANGALORE - 560042 #12;INDIAN ACADEMY OF SCIENCES BANGALORE ­ 560080

  5. Raman laser amplification in preformed and ionizing plasmas

    E-Print Network [OSTI]

    ~CPA! technique for generating ultra-intense, ultra-short laser pulses is determined by the damageRaman laser amplification in preformed and ionizing plasmas D.S. CLARK1 and N.J. FISCH2 1 Lawrence 1 October 2004; Accepted 2 November 2004! Abstract The recently proposed backward Raman laser

  6. Quantum-entanglement-initiated super Raman scattering

    SciTech Connect (OSTI)

    Agarwal, G. S. [Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)

    2011-02-15T23:59:59.000Z

    It has now been possible to prepare a chain of ions in an entangled state and thus the question arises: How will the optical properties of a chain of entangled ions differ from say a chain of independent particles? We investigate nonlinear optical processes in such chains. Since light scattering is quite a versatile technique to probe matter, we explicitly demonstrate the possibility of entanglement-produced super Raman scattering. Our results suggest the possibility of similar enhancement factors in other nonlinear processes like four-wave mixing.

  7. Optical pumping via incoherent Raman transitions

    E-Print Network [OSTI]

    A. D. Boozer; R. Miller; T. E. Northup; A. Boca; H. J. Kimble

    2007-10-04T23:59:59.000Z

    A new optical pumping scheme is presented that uses incoherent Raman transitions to prepare a trapped Cesium atom in a specific Zeeman state within the 6S_{1/2}, F=3 hyperfine manifold. An important advantage of this scheme over existing optical pumping schemes is that the atom can be prepared in any of the F=3 Zeeman states. We demonstrate the scheme in the context of cavity quantum electrodynamics, but the technique is equally applicable to a wide variety of atomic systems with hyperfine ground-state structure.

  8. Session: Advances in measuring methods (CT2.1) Track: Technical

    E-Print Network [OSTI]

    DTU (2) Siemens wind power (3) Vestas wind system The measurement of a power curve on large wind, LIDAR measurements of wind profiles have shown potential for power curve measurement and this device to the met mast data and will be compared to the power curve, which is measured in terms of the cup

  9. Single-shot hyperspectral coherent Raman planar imaging in the range 0–4200 cm?¹

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bohlin, Alexis [Sandia National Laboratories, Livermore, California 94550, USA; Kliewer, Christopher J. [Sandia National Laboratories, Livermore, California 94550, USA

    2014-10-20T23:59:59.000Z

    We propose a technique for ultrabroadband planar coherent Raman spectroscopy that enables wideband chemically selective mapping of molecular partition functions in the gas-phase within a single-laser-shot. A spectral region spanning 0–4200 cm?¹ is excited simultaneously, in principle allowing for coherent planar imaging of most all fundamental Raman-active modes. This unique instantaneous and spatially correlated assessment enables multiplexed studies of transient dynamical systems in a two-dimensional (2D) field. Here, we demonstrate single-laser-shot high temperature diagnostics of H?, with spatially resolved 2D measurement of transitions of both the pure-rotational H? S-branch and the vibrational H? Q-branch, analyzing the temperature contour of a reacting fuel-species as it evolves at a flame-front.

  10. Enhanced Raman sideband cooling of caesium atoms in a vapour-loaded magneto-optical trap

    E-Print Network [OSTI]

    Li, Y; Feng, G; Nute, J; Piano, S; Hackermuller, L; Ma, J; Xiao, L; Jia, S

    2015-01-01T23:59:59.000Z

    We report enhanced three-dimensional degenerated Raman sideband cooling (3D DRSC) of caesium (Cs) atoms in a standard single-cell vapour-loading magneto-optical trap. Our improved scheme involves using a separate repumping laser and optimized lattice detuning. We load $1.5 \\times 10^7$ atoms into the Raman lattice with a detuning of -15.5 GHz (to the ground F = 3 state). Enhanced 3D DRSC is used to cool them from 60 $\\mu$K to 1.7 $\\mu$K within 12 ms and the number of obtained atoms is about $1.2 \\times 10^7$. A theoretical model is proposed to simulate the measured number of trapped atoms. The result shows good agreement with the experimental data. The technique paves the way for loading a large number of ultracold Cs atoms into a crossed dipole trap and efficient evaporative cooling in a single-cell system.

  11. Single-shot hyperspectral coherent Raman planar imaging in the range 0–4200 cm?¹

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bohlin, Alexis; Kliewer, Christopher J.

    2014-10-20T23:59:59.000Z

    We propose a technique for ultrabroadband planar coherent Raman spectroscopy that enables wideband chemically selective mapping of molecular partition functions in the gas-phase within a single-laser-shot. A spectral region spanning 0–4200 cm?¹ is excited simultaneously, in principle allowing for coherent planar imaging of most all fundamental Raman-active modes. This unique instantaneous and spatially correlated assessment enables multiplexed studies of transient dynamical systems in a two-dimensional (2D) field. Here, we demonstrate single-laser-shot high temperature diagnostics of H?, with spatially resolved 2D measurement of transitions of both the pure-rotational H? S-branch and the vibrational H? Q-branch, analyzing the temperature contour of amore »reacting fuel-species as it evolves at a flame-front.« less

  12. The polarization field for pulsed Raman transitions

    SciTech Connect (OSTI)

    Shore, B.W.; Sacks, R.; Karr, T.

    1987-05-15T23:59:59.000Z

    This memo discusses the induced polarization field that occurs in the presence of Raman processes, and the propagation equations that result from this field. First the paper summarizes the relationship between the macroscopic polarization field and the microscopic dipole-moment expectation value. It summarizes expressions for the induced dipole moment that result from the adiabatic elimination of non-resonant molecular transitions, to produce an effective two-photon (Raman) Hamiltonian. Then it shows that the polarization field has a similar mode expansion to the electric field. Using this result the equations for pulse propagation of the electric field are described. These equations involve a generalized gain matrix and mode velocity, as well as a refractive index, each of which depends upon position and time. Finally the paper summarizes these results and exhibits succinctly the pulse propagation equations in the plane-wave slowly-varying envelope approximation. The equations presented here must be supplemented with excitation equations (or by steady-state results) for the molecules. The material presented here is a portion of a more extensive treatment of propagation to be presented separately.

  13. Measurement Measurement

    E-Print Network [OSTI]

    Type Measurement Type Measurement Type Measurement Type Measurement Catch Composition - Pelagic codes M Male F Female I Indeterminate U Unknown (not inspected) #12;Type Measurement Type Measurement Type Measurement Type Measurement Photos Comment Length 1 Version 1.2 6/2011 HookNo. Species name

  14. Ultraviolet (UV) Raman Spectroscopy Study of the Soret Effect in High-Pressure CO2-Water Solutions

    SciTech Connect (OSTI)

    Windisch, Charles F.; Maupin, Gary D.; McGrail, B. Peter

    2012-07-01T23:59:59.000Z

    Spatially resolved deep-UV Raman spectroscopy was applied to solutions of CO2 and H2O or D2O subject to a temperature gradient in a thermally regulated high-pressure concentric-tube Raman cell in an attempt to measure a Soret effect in the vicinity of the critical point of CO2. Although Raman spectra of solutions of CO2 dissolved in D2O, at 10 MPa and temperatures near the critical point of CO2, had adequate signal-to-noise and spatial resolution to observe a Soret effect with a Soret coefficient with magnitude |ST| > 0.03, no evidence for an effect of this size was obtained for applied temperature gradients up to 19 C. In contrast, the concentration of CO2 dissolved in H2O was shown to vary significantly across the temperature gradient when excess CO2 was present, but the results could be explained simply by the variation in CO2 solubility over the temperature range and not to kinetic factors. For mixtures of D2O dissolved in scCO2 at 10 MPa and temperatures close to the critical point of CO2, the Raman peaks for D2O were too weak to measure with confidence even at the limit of D2O solubility.

  15. Impact Assessment of Simulated Doppler Wind Lidars with a Multivariate Variational Assimilation in the Tropics

    E-Print Network [OSTI]

    Stoffelen, Ad

    forecast errors of the European Centre for Medium-Range Weather Forecasts (ECMWF) model. Tropical mass­windImpact Assessment of Simulated Doppler Wind Lidars with a Multivariate Variational Assimilation, De Bilt, Netherlands CHRISTOPHE ACCADIA AND PETER SCHL�SSEL European Organisation

  16. Lidars in Wind Energy Jakob Mann, Ferhat Bingl, Torben Mikkelsen, Ioannis Antoniou, Mike

    E-Print Network [OSTI]

    Lidars in Wind Energy Jakob Mann, Ferhat Bingöl, Torben Mikkelsen, Ioannis Antoniou, Mike Courtney, Gunner Larsen, Ebba Dellwik Juan Jose Trujillo* and Hans E. Jørgensen Wind Energy Department Risø of the presentation · Introduction to wind energy · Accurate profiles of the mean wind speed · Wakes behind turbines

  17. Biomass and Bioenergy 31 (2007) 646655 Estimating biomass of individual pine trees using airborne lidar

    E-Print Network [OSTI]

    2007-01-01T23:59:59.000Z

    Biomass and Bioenergy 31 (2007) 646­655 Estimating biomass of individual pine trees using airborne biomass and bio-energy feedstocks. The overall goal of this study was to develop a method for assessing aboveground biomass and component biomass for individual trees using airborne lidar data in forest settings

  18. LIDAR OBSERVATIONS AND COMPARISON WITH NUMERICAL SIMULATION OF A LAKE MICHIGAN LAND BREEZE FRONT

    E-Print Network [OSTI]

    Eloranta, Edwin W.

    of the Lake-Induced Convection Experiments (Lake-ICE), on December 21, 1997 the University of Wisconsin VolumeLIDAR OBSERVATIONS AND COMPARISON WITH NUMERICAL SIMULATION OF A LAKE MICHIGAN LAND BREEZE FRONT G circulation over Lake Michigan. Backscatter returns revealed a steady offshore flow extending 1.5 to 4 km

  19. Bistatic receiver model for airborne lidar returns incident on an imaging array from underwater objects

    E-Print Network [OSTI]

    Singer, Andrew C

    returns from the surrounding water medium and ocean bottom. Our results provide a generalization ocean lidar return, obtained by a CCD array. © 2002 Optical Society of America OCIS codes: 010.3640, 030 a laser to generate a short, high-powered pulse of light. The transmitted laser beam can penetrate the air

  20. Topographic accuracy assessment of bare earth lidar-derived unstructured meshes Matthew V. Bilskie

    E-Print Network [OSTI]

    Central Florida, University of

    : Shallow water equations Unstructured mesh Lidar DEM Storm surge Accuracy a b s t r a c t This study water equations model. A methodology is developed to compute root mean square error (RMSE) and the 95th, urban regions, etc.) and have coarse mesh resolution in areas outside the focus region (e.g. deep water

  1. Master Thesis: Dual-Doppler technique applied to scanning lidars for the characterization of

    E-Print Network [OSTI]

    Peinke, Joachim

    -lidar system was developed and installed at the offshore wind farm "alpha ventus". This system includes three and wind turbine wakes in large wind farms offshore. Wind Energy, 12(5):431­444, 2009. [2] Brian Hirth, D of multiple wakes in a wind farm M. van Dooren Supervisors: D. Trabucchi, K. S. Hansen University

  2. A High Efficiency Architecture for Cascaded Raman Fiber Lasers

    E-Print Network [OSTI]

    Supradeepa, V R; Headley, Clifford E; Yan, Man F; Palsdottir, Bera; Jakobsen, Dan

    2013-01-01T23:59:59.000Z

    We demonstrate a new high efficiency architecture for cascaded Raman fiber lasers based on a single pass cascaded amplifier configuration. Conversion is seeded at all intermediate Stokes wavelengths using a multi-wavelength seed source. A lower power Raman laser based on the conventional cascaded Raman resonator architecture provides a convenient seed source providing all the necessary wavelengths simultaneously. In this work we demonstrate a 1480nm laser pumped by an 1117nm Yb-doped fiber laser with maximum output power of 204W and conversion efficiency of 65% (quantum-limited efficiency is ~75%). We believe both the output power and conversion efficiency (relative to quantum-limited efficiency) are the highest reported for Raman fiber lasers.

  3. Detection of integrins using surface enhanced raman spectroscopy

    E-Print Network [OSTI]

    Gant, Virgil Alexander

    2005-08-29T23:59:59.000Z

    different integrins, (alpha)V(beta)3 and (alpha)5(beta)1. Results indicated that both colloids demonstrate SERS activity for varying concentrations of adenine as compared to standard non-enhanced Raman, however, only the citrate reduced colloid showed...

  4. Detection of Physiologically Relevant Alcohol Concentrations Using Raman Spectroscopy

    E-Print Network [OSTI]

    McKay, Joshua L.

    2006-08-16T23:59:59.000Z

    This is the first step in a series of studies to test the feasibility of using Raman Spectroscopy (RS) to non-invasively detect physiologically relevant blood alcohol concentrations. Blood tests, urine tests, and the breathalyzer are currently...

  5. Surface enhanced Raman spectroscopy on a flat graphene surface

    E-Print Network [OSTI]

    Xu, Weigao

    Surface enhanced Raman spectroscopy (SERS) is an attractive analytical technique, which enables single-molecule sensitive detection and provides its special chemical fingerprints. During the past decades, researchers have ...

  6. The Bolund Experiment Design of Measurement Campaign using CFD

    E-Print Network [OSTI]

    determination of mean wind, wind gradients and turbulence intensity on potential wind turbine positions complex terrain for reliable estimation of power production and wind turbine loads. · Development of remote sensing techniques (Lidar) for measuring wind conditions in complex terrain, including

  7. Isotopic dilution and solvent effect studies using raman difference spectroscopy

    E-Print Network [OSTI]

    Johnson, Andrew Norman

    1984-01-01T23:59:59.000Z

    ISOTOPIC DILUTION AND SOLVENT EFFECT STUDIES USING RAMAN DIFFERENCE SPECTROSCOPY A Thesis by ANDREW NORMAN JOHNSON Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE August 1984 Major Subject: Chemistry ISOTOPIC DILUTION AND SOLVENT EFFECT STUDIES USING RAMAN DIFFERENCE SPECTROSCOPY A Thesis by ANDREW NORMAN JOHNSON Approved as to style and content by: Jaan Laane (Chairman of Committee) J. . Bevan...

  8. Depth-resolved confocal micro-Raman spectroscopy for characterizing GaN-based light emitting diode structures

    SciTech Connect (OSTI)

    Chen, Wei-Liang; Lee, Yu-Yang; Chang, Yu-Ming, E-mail: ymchang@ntu.edu.tw [Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China)] [Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China); Chang, Chiao-Yun; Huang, Huei-Min; Lu, Tien-Chang [Department of Photonics, National Chiao Tung University, 30010 Hsinchu, Taiwan (China)] [Department of Photonics, National Chiao Tung University, 30010 Hsinchu, Taiwan (China)

    2013-11-15T23:59:59.000Z

    In this work, we demonstrate that depth-resolved confocal micro-Raman spectroscopy can be used to characterize the active layer of GaN-based LEDs. By taking the depth compression effect due to refraction index mismatch into account, the axial profiles of Raman peak intensities from the GaN capping layer toward the sapphire substrate can correctly match the LED structural dimension and allow the identification of unique Raman feature originated from the 0.3 ?m thick active layer of the studied LED. The strain variation in different sample depths can also be quantified by measuring the Raman shift of GaN A{sub 1}(LO) and E{sub 2}(high) phonon peaks. The capability of identifying the phonon structure of buried LED active layer and depth-resolving the strain distribution of LED structure makes this technique a potential optical and remote tool for in operando investigation of the electronic and structural properties of nitride-based LEDs.

  9. Detailed Hydrographic Feature Extraction from High-Resolution LiDAR Data

    SciTech Connect (OSTI)

    Danny L. Anderson

    2012-05-01T23:59:59.000Z

    Detailed hydrographic feature extraction from high-resolution light detection and ranging (LiDAR) data is investigated. Methods for quantitatively evaluating and comparing such extractions are presented, including the use of sinuosity and longitudinal root-mean-square-error (LRMSE). These metrics are then used to quantitatively compare stream networks in two studies. The first study examines the effect of raster cell size on watershed boundaries and stream networks delineated from LiDAR-derived digital elevation models (DEMs). The study confirmed that, with the greatly increased resolution of LiDAR data, smaller cell sizes generally yielded better stream network delineations, based on sinuosity and LRMSE. The second study demonstrates a new method of delineating a stream directly from LiDAR point clouds, without the intermediate step of deriving a DEM. Direct use of LiDAR point clouds could improve efficiency and accuracy of hydrographic feature extractions. The direct delineation method developed herein and termed “mDn”, is an extension of the D8 method that has been used for several decades with gridded raster data. The method divides the region around a starting point into sectors, using the LiDAR data points within each sector to determine an average slope, and selecting the sector with the greatest downward slope to determine the direction of flow. An mDn delineation was compared with a traditional grid-based delineation, using TauDEM, and other readily available, common stream data sets. Although, the TauDEM delineation yielded a sinuosity that more closely matches the reference, the mDn delineation yielded a sinuosity that was higher than either the TauDEM method or the existing published stream delineations. Furthermore, stream delineation using the mDn method yielded the smallest LRMSE.

  10. Workshop: Dados SAR e LIDAR para Anlise de Parmetros Biofsicos e de Estrutura Vertical de Tipologias Florestais (SAR and LIDAR Data for the Analysis of Biophysical Parameters and Vertical Structure from Forest Typologies)

    E-Print Network [OSTI]

    forests, allowing the optimized planning and operational management of forest resources. Microwave, Brazil) 10:45h Design and Implementation of Lidar & Radar Surveys for Forest Carbon Monitoring in REDD

  11. Method to determine and adjust the alignment of the transmitter and receiver fields of view of a LIDAR system

    DOE Patents [OSTI]

    Schmitt, Randal L. (Tijeras, NM); Henson, Tammy D. (Albuquerque, NM); Krumel, Leslie J. (Cedar Crest, NM); Hargis, Jr., Philip J. (Albuquerque, NM)

    2006-06-20T23:59:59.000Z

    A method to determine the alignment of the transmitter and receiver fields of view of a light detection and ranging (LIDAR) system. This method can be employed to determine the far-field intensity distribution of the transmitter beam, as well as the variations in transmitted laser beam pointing as a function of time, temperature, or other environmental variables that may affect the co-alignment of the LIDAR system components. In order to achieve proper alignment of the transmitter and receiver optical systems when a LIDAR system is being used in the field, this method employs a laser-beam-position-sensing detector as an integral part of the receiver optics of the LIDAR system.

  12. Microwave-stimulated Raman adiabatic passage in a Bose-Einstein condensate on an atom chip

    E-Print Network [OSTI]

    Dupont-Nivet, Matthieu; Laudat, Théo; Westbrook, Christoph I; Schwartz, Sylvain

    2015-01-01T23:59:59.000Z

    We report the achievement of stimulated Raman adiabatic passage (STIRAP) in the microwave frequency range between internal states of a Bose-Einstein condensate (BEC) magnetically trapped in the vicinity of an atom chip. The STIRAP protocol used in this experiment is robust to external perturbations as it is an adiabatic transfer, and power-efficient as it involves only resonant (or quasi-resonant) processes. Taking into account the effect of losses and collisions in a non-linear Bloch equations model, we show that the maximum transfer efficiency is obtained for non-zero values of the one- and two-photon detunings, which is confirmed quantitatively by our experimental measurements.

  13. Field Test Results of Using a Nacelle-Mounted Lidar for Improving Wind Energy Capture by Reducing Yaw Misalignment (Presentation)

    SciTech Connect (OSTI)

    Fleming, P.; Scholbrock, A.; Wright, A.

    2014-11-01T23:59:59.000Z

    Presented at the Nordic Wind Power Conference on November 5, 2014. This presentation describes field-test campaigns performed at the National Wind Technology Center in which lidar technology was used to improve the yaw alignment of the Controls Advanced Research Turbine (CART) 2 and CART3 wind turbines. The campaigns demonstrated that whether by learning a correction function to the nacelle vane, or by controlling yaw directly with the lidar signal, a significant improvement in power capture was demonstrated.

  14. Nanopillars array for surface enhanced Raman scattering

    SciTech Connect (OSTI)

    S.P. Chang, A; Bora, M; Nguyen, H T; Behymer, E M; Larson, C C; Britten, J A; Carter, J C; Bond, T C

    2011-04-14T23:59:59.000Z

    The authors present a new class of surface-enhanced Raman scattering (SERS) substrates based on lithographically-defined two-dimensional rectangular array of nanopillars. Two types of nanopillars within this class are discussed: vertical pillars and tapered pillars. For the vertical pillars, the gap between each pair of nanopillars is small enough (< 50 nm) such that highly confined plasmonic cavity resonances are supported between the pillars when light is incident upon them, and the anti-nodes of these resonances act as three-dimensional hotspots for SERS. For the tapered pillars, SERS enhancement arises from the nanofocusing effect due to the sharp tip on top. SERS experiments were carried out on these substrates using various concentrations of 1,2 bis-(4-pyridyl)-ethylene (BPE), benzenethiol (BT) monolayer and toluene vapor. The results show that SERS enhancement factor of over 0.5 x 10{sup 9} can be achieved, and BPE can be detected down to femto-molar concentration level. The results also show promising potential for the use of these substrates in environmental monitoring of gases and vapors such as volatile organic compounds.

  15. Study of the longitudinal distribution of power generated in a random distributed feedback Raman fibre laser with unidirectional pumping

    SciTech Connect (OSTI)

    Churkin, D V; El-Taher, A E; Vatnik, I D; Babin, Sergei A

    2012-09-30T23:59:59.000Z

    The longitudinal distribution of the Stokes-component power in a Raman fibre laser with a random distributed feedback and unidirectional pumping is measured. The fibre parameters (linear loss and Rayleigh backscattering coefficient) are calculated based on the distributions obtained. A numerical model is developed to describe the lasing power distribution. The simulation results are in good agreement with the experimental data. (optical fibres, lasers and amplifiers. properties and applications)

  16. The Raman spectrum of CaCO{sub 3} polymorphs calcite and aragonite: A combined experimental and computational study

    SciTech Connect (OSTI)

    De La Pierre, Marco, E-mail: cedric.carteret@univ-lorraine.fr, E-mail: marco.delapierre@unito.it; Maschio, Lorenzo; Orlando, Roberto; Dovesi, Roberto [Dipartimento di Chimica, Università di Torino and NIS (Nanostructured Interfaces and Surfaces) Centre of Excellence, Via P. Giuria 7, 10125 Torino (Italy)] [Dipartimento di Chimica, Università di Torino and NIS (Nanostructured Interfaces and Surfaces) Centre of Excellence, Via P. Giuria 7, 10125 Torino (Italy); Carteret, Cédric, E-mail: cedric.carteret@univ-lorraine.fr, E-mail: marco.delapierre@unito.it; André, Erwan [Laboratoire de Chimie Physique et Microbiologie pour l’Environnement (LCPME), UMR 7564, Université de Lorraine-CNRS, 405 rue de Vandoeuvre, 54601 Villers-lès-Nancy (France)] [Laboratoire de Chimie Physique et Microbiologie pour l’Environnement (LCPME), UMR 7564, Université de Lorraine-CNRS, 405 rue de Vandoeuvre, 54601 Villers-lès-Nancy (France)

    2014-04-28T23:59:59.000Z

    Powder and single crystal Raman spectra of the two most common phases of calcium carbonate are calculated with ab initio techniques (using a “hybrid” functional and a Gaussian-type basis set) and measured both at 80 K and room temperature. Frequencies of the Raman modes are in very good agreement between calculations and experiments: the mean absolute deviation at 80 K is 4 and 8 cm{sup ?1} for calcite and aragonite, respectively. As regards intensities, the agreement is in general good, although the computed values overestimate the measured ones in many cases. The combined analysis permits to identify almost all the fundamental experimental Raman peaks of the two compounds, with the exception of either modes with zero computed intensity or modes overlapping with more intense peaks. Additional peaks have been identified in both calcite and aragonite, which have been assigned to {sup 18}O satellite modes or overtones. The agreement between the computed and measured spectra is quite satisfactory; in particular, simulation permits to clearly distinguish between calcite and aragonite in the case of powder spectra, and among different polarization directions of each compound in the case of single crystal spectra.

  17. OAK 270 - The use of Lidar/radiometer (LIRAD) in the ARM program to obtain optical properties and microphysics of high and midlevel clouds

    SciTech Connect (OSTI)

    C.M.R. Platt; R.T. Austin; S.A. Young; and G.L. Stephens

    2002-12-13T23:59:59.000Z

    OAK 270 - The use of Lidar/Radiometer (LIRAD) in the ARM program to obtain optical properties and microphysics of high and midlevel clouds

  18. The application of surface-enhanced Raman spectroscopy for the detection of excitatory amino acids

    E-Print Network [OSTI]

    O'Neal, Dennis Patrick Doucet

    1999-01-01T23:59:59.000Z

    enhanced Raman spectroscopy (SERS) on aqueous silver colloids. This study examines methods to monitor the colloidal reactions for the calibration of the enhancement observed. Thirty second Raman spectral scans were taken utilizing a 50 mW argon laser...

  19. Coherent anti-Stokes Raman scattering (CARS) optimized by exploiting optical interference

    E-Print Network [OSTI]

    Wang, Xi

    2012-07-16T23:59:59.000Z

    The purpose of this work is to study the interference between the coherent nonresonant four-wave-mixing (FWM) background and the Raman-resonant signal in the coherent anti-Stokes Raman spectroscopy (CARS). The nonresonant background is usually...

  20. Combined confocal Raman and quantitative phase microscopy system for biomedical diagnosis

    E-Print Network [OSTI]

    Kang, Jeon Woong

    We have developed a novel multimodal microscopy system that incorporates confocal Raman, confocal reflectance, and quantitative phase microscopy (QPM) into a single imaging entity. Confocal Raman microscopy provides detailed ...

  1. Surface-Enhanced Raman Scattering Study on Graphene-Coated Metallic Nanostructure Substrates

    E-Print Network [OSTI]

    #12;Surface-Enhanced Raman Scattering Study on Graphene-Coated Metallic Nanostructure Substrates University, University Park, Pennsylvania 16802, United States *S Supporting Information ABSTRACT: Graphene, we combine graphene with conventional metallic surface- enhanced Raman scattering (SERS) substrates

  2. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    DOE Patents [OSTI]

    Bond, Tiziana C.; Miles, Robin; Davidson, James C.; Liu, Gang Logan

    2014-07-22T23:59:59.000Z

    Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

  3. Raman P. Singh School of Mechanical and Aerospace Engineering Phone (Tulsa): 918.594.8155

    E-Print Network [OSTI]

    Ghajar, Afshin J.

    Raman P. Singh School of Mechanical and Aerospace Engineering Phone (Tulsa): 918.594.8155 Oklahoma State University Phone (Stillwater): 405.744.1825 700 N. Greenwood Avenue, Tulsa, OK 74106 raman

  4. Raman Scattering from 1,3-Propanedithiol at a Hot Spot: Theory...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    from 1,3-Propanedithiol at a Hot Spot: Theory Meets Experiment. Raman Scattering from 1,3-Propanedithiol at a Hot Spot: Theory Meets Experiment. Abstract: We compute the Raman...

  5. Scientific investigations planned for the lidar in-space technology experiment (LITE)

    SciTech Connect (OSTI)

    McCormick, M.P.; Winker, D.M.; Browell, E.V. (NASA/Langley Research Center, Hampton, VA (United States)); Coakley, J.A. (Oregon State Univ., Corvallis (United States)); Gardner, C.S. (Univ. of Illinois, Urbana (United States)); Hoff, R.M. (Center for Atmospheric Research Experiments, Egbert, Ontario (Canada)); Kent, G.S. (Science and Technology Corp., Hampton, VA (United States)); Melfi, S.H. (NASA/Goddard Space Flight Center, Greenbelt, MD (United States)); Menzies, R.T. (Jet Propulsion Lab., Pasadena, CA (United States)); Platt, C.M.R. (CSIRO, Aspendale, Victoria (Australia)); Randall, D.A. (Colorado State Univ., Fort Collins (United States)); Reagan, J.A. (Univ. of Arizona, Tucson (United States))

    1993-02-01T23:59:59.000Z

    The Lidar In-Space Technology Experiment (LITE) is being developed by NASA/Langley Research Center for a series off lights on the space shuttle beginning in 1994. Employing a three-wave-length ND:YAG laser and a 1-m-diameter telescope, the system is a test-bed for the development of technology required for future operational spaceborne lidars. The system has been designed to observe clouds, tropospheric and stratospheric aerosols, characteristics of the planetary boundary layer, and stratospheric density and temperature perturbations with much greater resolution than is available from current orbiting sensors. In addition to providing unique datasets on these phenomena, the data obtained will be useful in improving retrieval algorithms currently in use. Observations of clouds and the planetary boundary layer will aid in the development of global climate model (GCM) parameterizations. This article briefly describes the LITE program and discusses the types of scientific investigations planned for the first flight.

  6. The Experimental Cloud Lidar Pilot Study (ECLIPS) for cloud-radiation research

    SciTech Connect (OSTI)

    Platt, C.M.; Young, S.A. [Division of Atmospheric Research, Victoria (Australia)] [Division of Atmospheric Research, Victoria (Australia); Carswell, A.I.; Pal, S.R. [York Univ., North York, Ontario (Canada)] [York Univ., North York, Ontario (Canada); McCormick, M.P.; Winker, D.M. [NASA Langley Research Center, Hampton, VA (United States)] [NASA Langley Research Center, Hampton, VA (United States); DelGuasta, M.; Stefanutti, L. [Institute Ricerca Onde Elettromagnetiche, Florence (Italy)] [Institute Ricerca Onde Elettromagnetiche, Florence (Italy); Eberhard, W.L.; Hardesty, M. [NOAA Environmental Technology Lab., Boulder, CO (United States)] [and others] [NOAA Environmental Technology Lab., Boulder, CO (United States); and others

    1994-09-01T23:59:59.000Z

    The Experimental Cloud Lidar Pilot Study (ECLIPS) was initiated to obtain statistics on cloud-base height, extinction, optical depth, cloud brokenness, and surface fluxes. Two observational phases have taken place, in October-December 1989 and April-July 1991, with intensive 30-day periods selected within the two time intervals. Data are being archived at NASA Langley Research Center, and, once there, are readily available to the international scientific community. 43 refs., 13 figs., 4 tabs.

  7. Linearly Organized Turbulence Structures Observed Over a Suburban Area by Dual-Doppler Lidar

    SciTech Connect (OSTI)

    Newsom, Rob K.; Calhoun, Ron; Ligon, David; Allwine, K Jerry

    2008-04-01T23:59:59.000Z

    Dual-Doppler lidar observations are used to investigate the structure and evolution of surface layer flow over a suburban area. The observations were made during the Joint Urban 2003 (JU2003) field experiment in Oklahoma City in the summer of 2003. This study focuses specifically on a 10-hour sequence of scan data beginning shortly after noon local time on July 7, 2003. During this period two coherent Doppler lidars performed overlapping low elevation angle sector scans upwind and south of Oklahoma City’s central business district (CBD). Radial velocity data from the two lidars are processed to reveal the structure and evolution of the horizontal velocity field in the surface layer throughout the afternoon and evening transition periods. The retrieved velocity fields clearly show a tendency for turbulence structures to be elongated in the direction of the mean flow throughout the entire 10-hour study period. As the stratification changed from unstable to weakly stable the turbulence structures became increasingly more linearly organized, and the cross-stream separation between high- and low-speed regoins decreased. The spatially resolved velocity fields are used to estimate streamwise and cross-stream turbulence length scales as functions of stability.

  8. Raman Database Considerations for Near-Infrared Systems

    SciTech Connect (OSTI)

    Kunkel, Brenda M.; Su, Yin-Fong; Tonkyn, Russell G.; Stephan, Eric G.; Joly, Alan G.; Birnbaum, Jerome C.; Jarman, Kristin H.; Johnson, Timothy J.

    2011-12-21T23:59:59.000Z

    For Raman spectroscopy the ability to detect is often limited by the existence and quality of the reference library to which field spectra are compared. Developing such databases is often labor- and resource-intensive; typically the generated data are not transferred to other instruments. Still other considerations may exist for comparing data at visible and ultraviolet excitation wavelengths such as resonance enhancement. However, for the common near-infrared wavelengths of 785, 830, 960, 1047 and 1064 nm where this is normally of a lesser concern, it is logical to consider whether data can be ported from one spectrometer to another so as to obviate the expensive and time-consuming process of generating reference data for each system. The present experiment generated a list of 125 chemical and common substances and formed a database from their corresponding 1064 nm spectra. The same molecules were then measured using a 785 nm system the new spectra were treated as “unknowns” and compared to the 1064 nm database using a commercial search algorithm. We found that at least 108 of the 125 spectra recorded at 785 nm were correctly identified using the search algorithm. For the few that were incorrectly identified, in most cases the spectra were extremely similar or the 785 nm signal was degraded due to fluorescence, as would occur regardless of reference data. Our results indicate that if the spectrometers are properly calibrated on both their wavelength and intensity axes, “foreign” data recorded at a different NIR wavelength can be successfully used as reference libraries

  9. Environmental temperature sensing using Raman spectra DTS fiber-optic methods

    E-Print Network [OSTI]

    Selker, John

    Environmental temperature sensing using Raman spectra DTS fiber-optic methods Scott W. Tyler,1 John January 2009. [1] Raman spectra distributed temperature sensing (DTS) by fiber-optic cables has recently sensing using Raman spectra DTS fiber-optic methods, Water Resour. Res., 45, W00D23, doi:10.1029/2008WR

  10. Description and performance of a highly versatile, low-cost fiber-optic confocal Raman microscope

    E-Print Network [OSTI]

    Myrick, Michael Lenn

    Description and performance of a highly versatile, low-cost fiber-optic confocal Raman microscope C for publication 29 September 1995 A versatile fiber-optic confocal Raman microscope has been developed. Fiber and disadvantages.11,12 We report here the development of an automated highly versatile fiber-optic confocal Raman

  11. CONTRIBUTED ARTICLE 117. Use of in situ Fiber-Optic Raman Spectroscopy to Replace

    E-Print Network [OSTI]

    Myrick, Michael Lenn

    CONTRIBUTED ARTICLE 117. Use of in situ Fiber-Optic Raman Spectroscopy to Replace Calorimetry. Abstract A method for real time determination of the percent cure of epoxies via in-situ fiber-optic Raman to be reliable to +/- 0.82% in the 40-90% cure range. Key words: Process monitoring, fiber optic, Raman

  12. Outline Phonon spectra of graphene Raman spectra of graphene Crystal lattice dynamics

    E-Print Network [OSTI]

    Seminar Heng Wang University of Konstanz July 11, 2013 Heng Wang University of Konstanz () Crystal lattice Raman spectra of graphene What is Raman scattering Applications of Raman spectroscopy of graphene Heng (2013). Heng Wang University of Konstanz () Crystal lattice dynamics July 11, 2013 3 / 19 #12;Outline

  13. Micro-Raman Spectroscopy of Algae: Composition Analysis and Fluorescence Background Behavior

    E-Print Network [OSTI]

    ARTICLE Micro-Raman Spectroscopy of Algae: Composition Analysis and Fluorescence Background performed using Stokes Raman scattering for compositional analysis of algae. Two algal species, Chlorella while acquiring Raman signals from the algae. The time dependence of fluorescence background is char

  14. Estimating the Wind Resource in Uttarakhand: Comparison of Dynamic Downscaling with Doppler Lidar Wind Measurements

    SciTech Connect (OSTI)

    Lundquist, J. K.; Pukayastha, A.; St. Martin, C.; Newsom, R.

    2014-03-01T23:59:59.000Z

    Previous estimates of the wind resources in Uttarakhand, India, suggest minimal wind resources in this region. To explore whether or not the complex terrain in fact provides localized regions of wind resource, the authors of this study employed a dynamic down scaling method with the Weather Research and Forecasting model, providing detailed estimates of winds at approximately 1 km resolution in the finest nested simulation.

  15. Modeling Plot-Level Biomass and Volume Using Airborne and Terrestrial Lidar Measurements

    E-Print Network [OSTI]

    Sheridan, Ryan D.

    2012-07-16T23:59:59.000Z

    The United States Forest Service (USFS) Forest Inventory and Analysis (FIA) program provides a diverse selection of data used to assess the status of the nation’s forested areas using sample locations dispersed throughout the country. Airborne...

  16. LIDAR measurements of wind turbine wake dyn_amics and comparison with an engineering model

    E-Print Network [OSTI]

    . Madsen, K. Thomsen, and T.J. Larsen. VVllke Ineandering - II pragmatic approach. Wind Energy. Accepted Endovved Chair of Wind Energy University of Stuttgart, Germany 2 Ris0 DTU National Laboratory Technical. In European Wind Energy Conference {711d Exhibitioll /lvIiloll Itoly. EWEC, May 2007. [2J C.C. Larsen, H. Aa

  17. Competition between extinction and enhancement in surface enhanced Raman spectroscopy

    E-Print Network [OSTI]

    van Dijk, Thomas; DeVetter, Brent M; Yang, Timothy K; Schulmerich, Matthew V; Murphy, Catherine J; Bhargava, Rohit; Carney, P Scott

    2013-01-01T23:59:59.000Z

    Conjugated metallic nanoparticles are a promising means to achieve ultrasensitive and multiplexed sensing in intact three-dimensional samples, especially for biological applications, via surface enhanced Raman scattering (SERS). We show that enhancement and extinction are linked and compete in a collection of metallic nanoparticles. Counterintuitively, the Raman signal vanishes when nanoparticles are excited at their plasmon resonance, while increasing nanoparticle concentrations at off-resonance excitation sometimes leads to decreased signal. We develop an effective medium theory that explains both phenomena. Optimal choices of excitation wavelength, individual particle enhancement factor and concentrations are indicated.

  18. Ring cavity for a Raman capillary waveguide amplifier

    DOE Patents [OSTI]

    Kurnit, N.A.

    1981-01-27T23:59:59.000Z

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  19. Ring cavity for a Raman capillary waveguide amplifir

    DOE Patents [OSTI]

    Kurnit, N.A.

    1981-01-27T23:59:59.000Z

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  20. Ring cavity for a Raman capillary waveguide amplifier

    DOE Patents [OSTI]

    Kurnit, N.A.

    1983-07-19T23:59:59.000Z

    Disclosed is a regenerative ring amplifier and regenerative ring oscillator which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO[sub 2] laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplifier Stokes signal is synchronous with the mode-locked spikes of the incoming CO[sub 2] laser pump signal. 6 figs.

  1. Structural and Raman scattering study of Ni-doped CoFe{sub 2}O{sub 4}

    SciTech Connect (OSTI)

    Kumar, Ashwini, E-mail: vdinesh33@rediffmail.com; Dar, Mashkoor A., E-mail: vdinesh33@rediffmail.com; Sharma, Poorva, E-mail: vdinesh33@rediffmail.com; Varshney, Dinesh, E-mail: vdinesh33@rediffmail.com [School of Physics, Vigyan Bhawan, Devi Ahilya University, Khandwa Road Campus, Indore-452001 (India)

    2014-04-24T23:59:59.000Z

    Raman scattering measurements were made on polycrystalline CoFe{sub 2}O{sub 4} and Co{sub 0.5}Ni{sub 0.5}Fe{sub 2}O{sub 4} ferrites as prepared by solid-state reaction route. Rietveld refined X-ray diffraction pattern confirmed the formation of single-phase and both of the samples perfectly indexed in cubic spinel structure with Fd3m space group. Slight reduction in the lattice parameter of Co{sub 0.5}Ni{sub 0.5}Fe{sub 2}O{sub 4} has been observed as compared to CoFe{sub 2}O{sub 4}. From Raman scattering spectra, a shoulder like feature has been observed in both of the compounds reveals that octahedral site is occupied by Co, Ni and Fe ions and tetrahedral site is occupied by only Fe ion.

  2. Proceedings of EARSeL-SIG-Workshop LIDAR, Dresden/FRG, June 16 17, 2000 EARSeL eProceedings No. 1 28

    E-Print Network [OSTI]

    Oldenburg, Carl von Ossietzky Universität

    and Development Center, Coastal and Hydraulics Laboratory, Joint Airborne Lidar Bathymetry Technical Center Hydrographic Operational Airborne Lidar Survey) system has been used to collect regional data gives an overview of SHOALS, the RSMDP and the SHOALS data sets that have been collected for the region

  3. TARSHA-KURDI, F., LANDES, T., GRUSSENMEYER, P., (2008). Extended RANSAC algorithm for automatic detection of building roof planes from Lidar data.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    2008-01-01T23:59:59.000Z

    detection of building roof planes from Lidar data. The Photogrammetric Journal of Finland. Vol. 21, n°1, 2008, pp.97-109. EXTENDED RANSAC ALGORITHM FOR AUTOMATIC DETECTION OF BUILDING ROOF PLANES FROM LIDAR the detection of 3D building roof planes are of crucial importance. For this purpose, this paper studies

  4. RESEARCH ARTICLE Open Access Raman characterization of Avocado Sunblotch

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    RESEARCH ARTICLE Open Access Raman characterization of Avocado Sunblotch viroid and its response of plants. To date the structural and conformational details of the cleavage of Avocado sunblotch viroid and they do not code for any protein. Viroids are divided into two families, the Avsunviroidae such as Avocado

  5. Raman scattering through a quantum-critical point

    E-Print Network [OSTI]

    Freericks, Jim

    frequency spectral weight with underdoping. J. G. Naeini et al., PRB 1999 J. K. Freericks, Georgetown, with an isosbestic point at about 2100 cm-1. #12;Experimental data for Kondo insulators · Nyhus et al, PRB 95 Raman been described by Devereaux and Kampf (PRB, 1999). · But no theory exists that can connect these two

  6. Probing the Intrinsic Properties of Exfoliated Graphene: Raman

    E-Print Network [OSTI]

    Heinz, Tony F.

    Probing the Intrinsic Properties of Exfoliated Graphene: Raman Spectroscopy of Free-standing graphene monolayers prepared by mechanical exfoliation of graphite are investigated. The graphene,7 or to solubilize macroscopic quantities of graphene,8 mechanical exfoliation of graphite9 currently remains

  7. hal00276997, Raman spectra of misoriented bilayer graphene

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    hal­00276997, version 1 ­ 5 May 2008 Raman spectra of misoriented bilayer graphene P. Poncharal 1 spectra from single layer graphene with a bilayer in which the two layers are arbitrarily misoriented to the similarity of the electronic structures of single layer graphene and misoriented bilayer graphene. Another

  8. CLIENT : Indian Academy of Sciences C. V. RAMAN AVENUE,

    E-Print Network [OSTI]

    Joshi, Yogesh Moreshwar

    1 CLIENT : Indian Academy of Sciences C. V. RAMAN AVENUE, SADASHIVNAGAR, BANGALORE ­ 560080 TENDER FOR : PROPOSED HOSTEL BLOCK AT INDIAN ACADEMY OF SCIENCES, FELLOWS RESIDENCY NEXT TO ISRO QUARTERS, JALAHALLI AND PLUMBING WORKS : 136-138 #12;3 INDIAN ACADEMY OF SCIENCES BANGALORE ­ 560080 NOTICE INVITING TENDER SEALED

  9. Postdoc Position in Microfluidics and Single Cell Raman Spectroscopy

    E-Print Network [OSTI]

    Horn, Matthias

    Postdoc Position in Microfluidics and Single Cell Raman Spectroscopy Department of Microbial and Environmental Microfluidics Group (http://web.mit.edu/romanstocker) Department of Civil & Environmental (junior or senior) with strong expertise in microfluidics and an interest in applying it to microbial

  10. Superhydrophobic surface enhanced Raman scattering sensing using Janus particle arrays

    E-Print Network [OSTI]

    Superhydrophobic surface enhanced Raman scattering sensing using Janus particle arrays realized deposition is used to prepare polystyrene (PS)­Ag Janus particle arrays with superhydrophobic properties. Analyte molecules can be significantly enriched using the superhydrophobic properties of the PS­Ag Janus

  11. Technical Notes UV Resonance Raman Spectroscopic Detection of

    E-Print Network [OSTI]

    Asher, Sanford A.

    - in wastewater for the real-time control of water treatment plants. The reliability and performance of biological nutrient removal (BNR) wastewater treatment plants (WWTPs) can be enhanced by the ability to monitor the utility of UV resonance Raman3-8 spectroscopy to monitor nitrate and nitrite in wastewater treatment

  12. Soret Effect Study on High-Pressure CO2-Water Solutions Using UV-Raman Spectroscopy and a Concentric-Tube Optical Cell

    SciTech Connect (OSTI)

    Windisch, Charles F.; McGrail, B. Peter; Maupin, Gary D.

    2012-01-01T23:59:59.000Z

    Spatially resolved deep-UV Raman spectroscopy was applied to solutions of CO2 and H2O (or D2O), which were subject to a temperature gradient in a thermally regulated high-pressure concentric-tube Raman cell in an attempt to measure a Soret effect in the vicinity of the critical point of CO2. Although Raman spectra of solutions of CO2 dissolved in D2O at 10 MPa and temperatures near the critical point of CO2 had adequate signal-to-noise and spatial resolution to observe a Soret effect with a Soret coefficient with magnitude of |ST| > 0.03, no evidence for an effect of this size was obtained for applied temperature gradients up to 19oC. The presence of 1 M NaCl did not make a difference. In contrast, the concentration of CO2 dissolved in H2O was shown to vary significantly across the temperature gradient when excess CO2 was present, but the results could be explained simply by the variation in CO2 solubility over the temperature range and not to kinetic factors. For mixtures of D2O dissolved in scCO2 at 10 MPa and temperatures close to the critical point of CO2, the Raman peaks for H2O were too weak to measure with confidence even at the limit of D2O solubility.

  13. Raman Analysis of Perrhenate and Pertechnetate in Alkali Salts and Borosilicate Glasses

    SciTech Connect (OSTI)

    Gassman, Paul L.; McCloy, John S.; Soderquist, Chuck Z.; Schweiger, Michael J.

    2014-01-03T23:59:59.000Z

    Sodium borosilicate glasses containing various concentrations of rhenium or technetium were fabricated, and their vibrational spectra studied using a Raman microscope. Spectra were interpreted with reference to new high resolution measurements of alkali pertechnetates and perrhenates NaReO4, KReO4, NaTcO4, and KTcO4. At low concentrations of ReO4- or TcO4-, glass spectra show weak peaks superimposed on a dominant spectrum of glass characteristic of silicate and borate network vibrations. At high concentrations, sharp peaks characteristic of crystal field splitting and C4h symmetry dominate the spectra of glasses, indicating alkali nearby tetrahedral Re or Tc. Often peaks indicative of both the K and Na pertechnetates/ perrhenates are evident in the Raman spectrum, with the latter being favored at high additions of the source chemical, since Na is more prevalent in the glass and ion exchange takes place. These results have significance to immobilization of nuclear waste containing radioactive 99Tc in glass for ultimate disposal.

  14. Micro-Raman investigations of InN-GaN core-shell nanowires on Si (111) substrate

    SciTech Connect (OSTI)

    Sangeetha, P.; Ramakrishnan, V. [Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai-625 021 (India); Jeganathan, K. [Centre for Nanoscience and Nanotechnology, School of Physics, Bharathidasan University, Tiruchirappalli-620 024 (India)

    2013-06-15T23:59:59.000Z

    The electron-phonon interactions in InN-GaN core-shell nanowires grown by plasma assisted- molecular beam epitaxy (MBE) on Si (111) substrate have been analysed using micro-Raman spectroscopic technique with the excitation wavelength of 633, 488 and 325 nm. The Raman scattering at 633 nm reveals the characteristic E{sub 2} (high) and A{sub 1} (LO) phonon mode of InN core at 490 and 590 cm{sup -1} respectively and E{sub 2} (high) phonon mode of GaN shell at 573 cm{sup -1}. The free carrier concentration of InN core is found to be low in the order {approx} 10{sup 16} cm{sup -3} due to the screening of charge carriers by thin GaN shell. Diameter of InN core evaluated using the spatial correlation model is consistent with the transmission electron microscopic measurement of {approx}15 nm. The phonon-life time of core-shell nanowire structure is estimated to be {approx}0.4 ps. The micro-Raman mapping and its corresponding localised spectra for 325 nm excitation exhibit intense E{sub 2} (high) phonon mode of GaN shell at 573 cm{sup -1} as the decrease of laser interaction length and the signal intensity is quenched at the voids due to high spacing of NWs.

  15. Structural, optoelectronic, infrared and Raman spectra of orthorhombic SrSnO{sub 3} from DFT calculations

    SciTech Connect (OSTI)

    Moreira, E. [Departamento de Fisica Teorica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Henriques, J.M. [Centro de Educacao e Saude, Universidade Federal de Campina Grande, Campus Cuite, 58175-000 Cuite-PB (Brazil); Azevedo, D.L. [Departamento de Fisica, Universidade Federal do Maranhao, Centro de Ciencias Exatas e Tecnologia, 65085-580 Sao Luis-MA (Brazil); Departamento de Fisica Teorica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Caetano, E.W.S., E-mail: ewcaetano@gmail.co [Instituto Federal de Educacao, Ciencia e Tecnologia do Ceara, Av. 13 de Maio, 2081, Benfica, 60040-531 Fortaleza-CE (Brazil); Freire, V.N. [Departamento de Fisica, Universidade Federal do Ceara, Centro de Ciencias, Caixa Postal 6030, Campus do Pici, 60455-760 Fortaleza-CE (Brazil); Albuquerque, E.L. [Departamento de Biofisica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil)

    2011-04-15T23:59:59.000Z

    Orthorhombic SrSnO{sub 3} was investigated using density functional theory (DFT) considering both the local density and generalized gradient approximations, LDA and GGA, respectively. The electronic band structure, density of states, complex dielectric function, optical absorption, and the infrared and Raman spectra were computed. Calculated lattice parameters are close to the experimental measurements, and an indirect band gap E(S{yields}{Gamma})=1.97eV (2.27 eV) was obtained within the GGA (LDA) level of calculation. Effective masses for holes and electrons were estimated, being very anisotropic in comparison with similar results for orthorhombic CaSnO{sub 3}. The complex dielectric function and the optical absorption of SrSnO{sub 3} were shown to be sensitive to the plane of polarization of the incident light. The infrared spectrum between 100 and 600 cm{sup -1} was obtained, with its main peaks being assigned, and a nice agreement between experimental and theoretical peaks of the Raman spectrum of orthorhombic SrSnO{sub 3} was achieved. -- Graphical abstract: Orthorhombic SrSnO{sub 3}: a view of the unit cell (left) and plots showing the calculated and experimental Raman spectra (right). Display Omitted Research highlights: {yields} We have performed DFT calculations on orthorhombic SrSnO{sub 3} crystals, obtaining their structural, electronical and optical properties. {yields} An indirect band gap was obtained, and anisotropic effective masses were found for both electrons and holes. {yields} The complex dielectric function and the optical absorption of SrSnO{sub 3} were shown to be very sensitive to the plane of polarization of the incident light. {yields} The infrared spectrum between 100 and 600 cm{sup -1} was obtained, with its main peaks being assigned, and a nice agreement between experimental and theoretical peaks of the Raman spectrum was achieved.

  16. ARM - Evaluation Product - MicroPulse LIDAR Cloud Optical Depth (MPLCOD)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006Datastreamstwrcam40m Documentation DataDatastreamsxsaprhsrhi1-minProductsMicroPulse LIDAR Cloud Optical Depth

  17. ARM - Field Campaign - NASA Coordinated Airborne CO2 Lidar Flight Test

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa- Polarization Diversity Lidar (PDL)govCampaignsMixed-Phase Arctic Cloud

  18. Ultrafast stimulated Raman parallel adiabatic passage by shaped pulses

    E-Print Network [OSTI]

    G. Dridi; S. Guerin; V. Hakobyan; H. R. Jauslin; H. Eleuch

    2009-10-06T23:59:59.000Z

    We present a general and versatile technique of population transfer based on {\\it parallel adiabatic passage} by femtosecond shaped pulses. Their amplitude and phase are specifically designed to optimize the adiabatic passage corresponding to parallel eigenvalues at all times. We show that this technique allows the robust adiabatic population transfer in a Raman system with the total pulse area as low as 3 $\\pi$, corresponding to a fluence of one order of magnitude below the conventional stimulated Raman adiabatic passage process. This process of short duration, typically pico- and subpicosecond, is easily implementable with the modern pulse shaper technology and opens the possibility of ultrafast robust population transfer with interesting applications in quantum information processing.

  19. Surface-enhanced raman optical data storage system

    DOE Patents [OSTI]

    Vo-Dinh, Tuan (Knoxville, TN)

    1991-01-01T23:59:59.000Z

    A method and apparatus for a Surface-Enhanced Raman Optical Data Storage (SERODS) System is disclosed. A medium which exhibits the Surface Enhanced Raman Scattering (SERS) phenomenon has data written onto its surface of microenvironment by means of a write-on procedure which disturbs the surface or microenvironment of the medium and results in the medium having a changed SERS emission when excited. The write-on procedure is controlled by a signal that corresponds to the data to be stored so that the disturbed regions on the storage device (e.g., disk) represent the data. After the data is written onto the storage device it is read by exciting the surface of the storage device with an appropriate radiation source and detecting changes in the SERS emission to produce a detection signal. The data is then reproduced from the detection signal.

  20. Surface-Enhanced Raman Optical Data Storage system

    DOE Patents [OSTI]

    Vo-Dinh, T.

    1991-03-12T23:59:59.000Z

    A method and apparatus for a Surface-Enhanced Raman Optical Data Storage (SERODS) System are disclosed. A medium which exhibits the Surface Enhanced Raman Scattering (SERS) phenomenon has data written onto its surface of microenvironment by means of a write-on procedure which disturbs the surface or microenvironment of the medium and results in the medium having a changed SERS emission when excited. The write-on procedure is controlled by a signal that corresponds to the data to be stored so that the disturbed regions on the storage device (e.g., disk) represent the data. After the data is written onto the storage device it is read by exciting the surface of the storage device with an appropriate radiation source and detecting changes in the SERS emission to produce a detection signal. The data is then reproduced from the detection signal. 5 figures.

  1. Electrochromic reactions in manganese oxides I. Raman analysis

    SciTech Connect (OSTI)

    Bernard, M.C.; Hugot-Le Goff, A.; Thi, B.V. (Univ. Pierre et Marie Curie, Paris (France). UPR 15 du CNRS Physique des Liquides et Electrochimie); Cordoba de Torresi, S. (Univ. Estadual de Campinas (Brazil). Dept. de Fisica Aplicada)

    1993-11-01T23:59:59.000Z

    Like nickel oxide, manganese oxide is a widely studied material in the primary batteries field. The reactions taking place during voltametric cycling of manganese oxides can be determined using in situ Raman spectroscopy. The main difficulty for the oxide identification is to obtain relevant Raman reference spectra because of the many possible compounds and, for some of these compounds, of their instability in the laser beam. As a consequence, several modifications of different tetra-, tri- and divalent manganese oxides and oxyhydroxides were carefully studied. The electrochromic behavior of three types of manganese oxides, two prepared by thermal oxidations and the other by electrochemical deposition, were then compared. The presence of nonstoichiometry in the pristine material was necessary to obtain a reversible electrochromic effect. The reaction during electrochromic cycling is more complicated than a simple passage from MnO[sub 2] to MnOOH.

  2. Stochastic Liouville Equations for Femtosecond Stimulated Raman Spectroscopy

    E-Print Network [OSTI]

    Agarwalla, Bijay Kumar; Dorfman, Konstantin E; Mukamel, Shaul

    2015-01-01T23:59:59.000Z

    Electron and vibrational dynamics of molecules are commonly studied by subjecting them to two interactions with a fast actinic pulse that prepares them in a nonstationary state and after a variable delay period $T$, probing them with a Raman process induced by a combination of a broadband and a narrowband pulse. This technique known as femtosecond stimulated Raman spectroscopy (FSRS) can effectively probe time resolved vibrational resonances. We show how FSRS signals can be modeled and interpreted using the stochastic Liouville equations (SLE) originally developed for NMR lineshapes. The SLE provides a convenient simulation protocol that can describe complex dynamics due to coupling to collective coordinates at much lower cost that a full dynamical simulation. The origin of the dispersive features which appear when there is no separation of timescales between vibrational variations and dephasing is clarified.

  3. Multi mode nano scale Raman echo quantum memory

    E-Print Network [OSTI]

    S. A. Moiseev; E. S. Moiseev

    2010-01-31T23:59:59.000Z

    Low loss magnetic surface plasmon polariton (SPP) modes characterized by enhanced electrical field component and subwavelength confinement on the dielectric and negative-index metamaterial interface are presented. We demonstrate a possibility of storage and perfect retrieval of the low loss magnetic SPP fields by using a photon echo quantum memory on Raman atomic transition. We describe specific properties of the proposed technique which opens a possibility for efficient nano scale multi-mode quantum memory.

  4. The infrared and Raman spectra of N-alkyl ethylenimines

    E-Print Network [OSTI]

    Ashby, Theodore Leroy

    1968-01-01T23:59:59.000Z

    and Assi nments. . . . . . . . . . . . . . . , 5 A, Structural Considerations. . . . ~ . . . , . . . , 5 B, Assi"na ent of Spectra. . . . . . , . . . . . . . . . . 9 1, Yethod, 9 2. N-Yethyl Ethylenimine, . . . . , . . . . . . . 10 3. N-Ethyl... the Or ientation of the Principal Axes. Page 2. The Infrared Spectrum of I!-Yythyl Ethy- lenimine from 4000 to 50 cm . . . . . . . , . . . . 11 3. The Raman Spectrum of !! i~'. ethyl Ethylenimine. 13 4. The Infrared Spectrum of N-Ethyl Ethy- lenimine from...

  5. Raman spectra of aligned carbon micro-coils and their impedance characteristics under loads

    SciTech Connect (OSTI)

    Tao, Wang; Yabo, Zhu, E-mail: zhuyabo@163.com; Heliang, Fan; Zhicheng, Ju; Lei, Chen; Zhengyuan, Wang [School of Materials Science and Engineering, China University of Mining and Technology, Xu Zhou, Jiangsu 221116 (China)

    2014-02-21T23:59:59.000Z

    Scanning and transmission electron microscopy were used to characterize the morphology of the carbon microcoils (CMCs). The Raman spectra showed that CMCs had local regular structure as I{sub D}/I{sub G}?=?0.841. Then, aligned CMCs/silicone–rubber composites (5?×?5?×?1 mm{sup 3}) were fabricated by coating of silicone rubber on the CMCs. Their alternating current impedance characteristics were measured as a function of applied load and the pressure sensitivity was discussed. The results showed that the impedance decreased as the increasing applied load, and the sample with less CMCs owned high pressure sensitivity, which indicated a novel composite film could act as an alternative of tactile sensor.

  6. Lidar Investigation of Tropical Nocturnal Boundary Layer Aerosols and Cloud Macrophysics

    SciTech Connect (OSTI)

    Manoj, M. G.; Devara, PC S.; Taraphdar, Sourav

    2013-10-01T23:59:59.000Z

    Observational evidence of two-way association between nocturnal boundary layer aerosols and cloud macrophysical properties under different meteorological conditions is reported in this paper. The study has been conducted during 2008-09 employing a high space-time resolution polarimetric micro-pulse lidar over a tropical urban station in India. Firstly, the study highlights the crucial role of boundary layer aerosols and background meteorology on the formation and structure of low-level stratiform clouds in the backdrop of different atmospheric stability conditions. Turbulent mixing induced by the wind shear at the station, which is associated with a complex terrain, is found to play a pivotal role in the formation and structural evolution of nocturnal boundary layer clouds. Secondly, it is shown that the trapping of energy in the form of outgoing terrestrial radiation by the overlying low-level clouds can enhance the aerosol mixing height associated with the nocturnal boundary layer. To substantiate this, the long-wave heating associated with cloud capping has been quantitatively estimated in an indirect way by employing an Advanced Research Weather Research and Forecasting (WRF-ARW) model version 2.2 developed by National Center for Atmospheric Research (NCAR), Colorado, USA, and supplementary data sets; and differentiated against other heating mechanisms. The present investigation as well establishes the potential of lidar remote-sensing technique in exploring some of the intriguing aspects of the cloud-environment relationship.

  7. Determination of saccharides and ethanol from biomass conversion using Raman spectroscopy: Effects of pretreatment and enzyme composition

    SciTech Connect (OSTI)

    Shih, Chien-Ju

    2010-05-16T23:59:59.000Z

    This dissertation focuses on the development of facile and rapid quantitative Raman spectroscopy measurements for the determination of conversion products in producing bioethanol from corn stover. Raman spectroscopy was chosen to determine glucose, xylose and ethanol in complex hydrolysis and fermentation matrices. Chapter 1 describes the motives and main goals of this work, and includes an introduction to biomass, commonly used pretreatment methods, hydrolysis and fermentation reactions. The principles of Raman spectroscopy, its advantages and applications related to biomass analysis are also illustrated. Chapter 2 and 3 comprise two published or submitted manuscripts, and the thesis concludes with an appendix. In Chapter 2, a Raman spectroscopic protocol is described to study the efficiency of enzymatic hydrolysis of cellulose by measuring the main product in hydrolysate, glucose. Two commonly utilized pretreatment methods were investigated in order to understand their effect on glucose measurements by Raman spectroscopy. Second, a similar method was set up to determine the concentration of ethanol in fermentation broth. Both of these measurements are challenged by the presence of complex matrices. In Chapter 3, a quantitative comparison of pretreatment protocols and the effect of enzyme composition are studied using systematic methods. A multipeak fitting algorithm was developed to analyze spectra of hydrolysate containing two analytes: glucose and xylose. Chapter 4 concludes with a future perspective of this research area. An appendix describes a convenient, rapid spectrophotometric method developed to measure cadmium in water. This method requires relatively low cost instrumentation and can be used in microgravity, such as space shuttles or the International Space Station. This work was performed under the supervision of Professor Marc Porter while at Iowa State University. Research related to producing biofuel from bio-renewable resources, especially bioethanol from biomass, has grown significantly in the past decade due to the high demand and rising costs of fossil fuels. More than 3 percent of the energy consumption in the U.S. is derived from renewable biomass, mostly through industrial heat and steam production by the pulp and paper industry, and electricity generation from municipal solid waste (MSW) and forest industry residues. The utilization of food-based biomass to make fuels has been widely criticized because it may increase food shortages throughout the world and raise the cost of food. Thus, nonfood-based and plentiful lignocellulosic feedstocks, such as corn stover, perennial grass, bagasse, sorghum, wheat/rice straw, herbaceous and woody crops, have great potential to be new bio-renewable sources for energy production. Given that many varieties of biomass are available, there is need for a rapid, simple, high-throughput method to screen the conversion of many plant varieties. The most suitable species for each geographic region must be determined, as well as the optimal stage of harvest, impacts of environmental conditions (temperature, soil, pH, etc.). Various genetically modified plants should be studied in order to establish the desired biomass in bioethanol production. The main screening challenge, however, is the complexity of plant cell wall structures that make reliable and sensitive analysis difficult. To date, one of the most popular methods to produce lignocellulosic ethanol is to perform enzymatic hydrolysis followed by fermentation of the hydrolysate with yeast. There are several vital needs related to the field of chemistry that have been suggested as primary research foci needed to effectively improve lignocellulosic ethanol production. These topics include overcoming the recalcitrance of cellulosic biomass, the pervasiveness of pretreatment, advanced biological processing and better feedstocks. In this thesis, a novel approach using Raman spectroscopy has been developed to address important issues related to bioethanol generation, which will aid the research aimed to solve the topics m

  8. Plasmon enhanced Raman scattering effect for an atom near a carbon nanotube

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bondarev, I. V.

    2015-01-01T23:59:59.000Z

    Quantum electrodynamics theory of the resonance Raman scattering is developed for an atom in a close proximity to a carbon nanotube. The theory predicts a dramatic enhancement of the Raman intensity in the strong atomic coupling regime to nanotube plasmon near-fields. This resonance scattering is a manifestation of the general electromagnetic surface enhanced Raman scattering effect, and can be used in designing efficient nanotube based optical sensing substrates for single atom detection, precision spontaneous emission control, and manipulation.

  9. Influence of coherent Raman scattering on coherent population trapping in atomic sodium vapor

    SciTech Connect (OSTI)

    Wong, Vincent; Bennink, Ryan S.; Marino, Alberto M.; Boyd, Robert W.; Stroud, C.R. Jr.; Narducci, F.A. [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); EO Sensors Division, Naval Air Systems Command, Patuxent River, Maryland 20670 (United States)

    2004-11-01T23:59:59.000Z

    We study how coherent Stokes and anti-Stokes Raman scattering influence coherent population trapping. In an experiment using an atomic sodium vapor cell we observe induced transparency, induced absorption, and gain features, all of subnatural linewidth. The electromagnetically induced resonance is a peak or a dip depending on which side of the optical transition the fields are tuned to, and thus whether coherent anti-Stokes Raman scattering or coherent Stokes Raman scattering is the dominant process.

  10. Understanding the application of Raman spectroscopy to the detection of traces of life

    E-Print Network [OSTI]

    Marshall, Craig P.; Edwards, Howell G.M.; Jehlicka, Jan

    2010-03-01T23:59:59.000Z

    problem. 2.3. Accepted biogenic Raman spectral signatures Due to the current controversy of using Raman spectros- copy as a tool to asses the biogenicity of Archean putative microfossils, we will explore what are known and agreed- upon spectral signatures.... Conceivably, this could offer information on the relatedness between Earth and potential martian microbes. Investigations of endolithic communities from extreme habitats on Earth have demonstrated that Raman spectros- copy is an excellent tool to detect...

  11. Raman scattering from defects in GaN: The question of vibrational or electronic scattering mechanism

    E-Print Network [OSTI]

    Nabben, Reinhard

    Raman scattering from defects in GaN: The question of vibrational or electronic scattering on defects in GaN, which appear in the Raman spectra as sharp and intense lines in the low-energy region from into the GaN material. S0163-1829 98 00344-0 I. INTRODUCTION Low-temperature Raman spectra of GaN films grown

  12. Raman scattering in Si/SiGe nanostructures: Revealing chemical composition, strain, intermixing, and heat dissipation

    SciTech Connect (OSTI)

    Mala, S. A.; Tsybeskov, L., E-mail: tsybesko@njit.edu [Department of Electrical and Computer Engineering, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States); Lockwood, D. J.; Wu, X.; Baribeau, J.-M. [National Research Council, Ottawa, Ontario K1A 0R6 (Canada)

    2014-07-07T23:59:59.000Z

    We present a quantitative analysis of Raman scattering in various Si/Si{sub 1-x}Ge{sub x} multilayered nanostructures with well-defined Ge composition (x) and layer thicknesses. Using Raman and transmission electron microscopy data, we discuss and model Si/SiGe intermixing and strain. By analyzing Stokes and anti-Stokes Raman signals, we calculate temperature and discuss heat dissipation in the samples under intense laser illumination.

  13. Quantifying and relating land-surface and subsurface variability in permafrost environments using LiDAR and surface geophysical

    E-Print Network [OSTI]

    LiDAR and surface geophysical datasets S. S. Hubbard & C. Gangodagamage & B. Dafflon & H. Wainwright. Wullschleger Abstract The value of remote sensing and surface geophysical data for characterizing the spatial to extract geomorphic metrics, which potentially indicate drainage potential. Geophysical data were used

  14. Lidar observations of polar mesospheric clouds at Rothera, Antarctica (67.5S, 68.0W)

    E-Print Network [OSTI]

    Chu, Xinzhao

    Chu,1 Graeme J. Nott,2 Patrick J. Espy,2 Chester S. Gardner,1 Jan C. Diettrich,2 Mark A. Clilverd,2 and Martin J. Jarvis2 Received 15 September 2003; revised 15 October 2003; accepted 30 October 2003. Diettrich, M. A. Clilverd, and M. J. Jarvis (2004), Lidar observations of polar mesospheric clouds

  15. Estimating forest structural characteristics with airborne lidar scanning and a near-real time profiling laser systems

    E-Print Network [OSTI]

    Zhao, Kaiguang

    2009-05-15T23:59:59.000Z

    for realtime remote sensing platforms, e.g., to provide timely information for urgent applications. This study aims to develop an airborne profiling LiDAR system, featured with on-the-fly data processing, for near real- or real- time forest inventory...

  16. Using LiDAR and normalized difference vegetation index to remotely determine LAI and percent canopy cover at varying scales

    E-Print Network [OSTI]

    Griffin, Alicia Marie Rutledge

    2009-05-15T23:59:59.000Z

    The use of airborne LiDAR (Light Detection and Ranging) as a direct method to evaluate forest canopy parameters is vital in addressing both forest management and ecological concerns. The overall goal of this study was to develop the use of airborne...

  17. Tunable excitation source for coherent Raman spectroscopy based on a single fiber laser

    E-Print Network [OSTI]

    Adany, Peter; Arnett, David C.; Johnson, Carey K.; Hui, Rongqing

    2011-10-01T23:59:59.000Z

    We demonstrate a wavelength tunable optical excitation source for coherent Raman scattering (CRS) spectroscopy based on a single femtosecondfiber laser. Electrically controlled wavelength tuning of Stokes optical pulses ...

  18. Multifunctional porous silicon nanopillar arrays: antireflection, superhydrophobicity, photoluminescence, and surface-enhanced Raman scattering

    E-Print Network [OSTI]

    Multifunctional porous silicon nanopillar arrays: antireflection, superhydrophobicity nanopillar arrays: antireflection, superhydrophobicity, photoluminescence, and surface-enhanced Raman without any optimization, and approaching superhydrophobic behavior with increasing aspect ratio

  19. Self-heating study of an AlGaN/GaN-based heterostructure field-effect transistor using ultraviolet micro-Raman scattering

    E-Print Network [OSTI]

    Holtz, Mark

    Self-heating study of an AlGaN/GaN-based heterostructure field-effect transistor using ultraviolet We report micro-Raman studies of self-heating in an AlGaN/GaN heterostructure field-effect transistorC substrate, at the same lateral position. Combined, we depth profile the self-heating. Measured T in the 2DEG

  20. Wind Scanner: A full-scale Laser Facility for Wind and Turbulence Measurements around large Wind Turbines

    E-Print Network [OSTI]

    Wind Scanner: A full-scale Laser Facility for Wind and Turbulence Measurements around large Wind Turbines Torben Mikkelsen, Jakob Mann and Michael Courtney Wind Energy Department, Risø National Laboratory:Torben.Mikkelsen@Risoe.dk Summary RISØ DTU has started to build a newly designed laser-based lidar scanning facility for remote wind

  1. Sedimentological Reinterpretation of Surficial Unconsolidated Debris Flows and Stream Deposits of the Southern Flanks of Grand Mesa, CO: An Integrated LiDAR Approach

    E-Print Network [OSTI]

    Blakeley, Mitchell W.

    2014-08-08T23:59:59.000Z

    . This study developed a sedimentological description and interpretation of these deposits and tested the capabilities of terrestrial LiDAR (Light Detection and Ranging) for use in sedimentological studies. This research addressed the origin of the deposits...

  2. Many-body theory of surface-enhanced Raman scattering

    E-Print Network [OSTI]

    David J. Masiello; George C. Schatz

    2008-09-18T23:59:59.000Z

    A many-body Green's function approach to the microscopic theory of surface-enhanced Raman scattering is presented. Interaction effects between a general molecular system and a spatially anisotropic metal particle supporting plasmon excitations in the presence of an external radiation field are systematically included through many-body perturbation theory. Reduction of the exact effects of molecular-electronic correlation to the level of Hartree-Fock mean-field theory is made for practical initial implementation, while description of collective oscillations of conduction electrons in the metal is reduced to that of a classical plasma density; extension of the former to a Kohn-Sham density-functional or second-order M{\\o}ller-Plesset perturbation theory is discussed; further specialization of the latter to the random-phase approximation allows for several salient features of the formalism to be highlighted without need for numerical computation. Scattering and linear-response properties of the coupled system subjected to an external perturbing electric field in the electric-dipole interaction approximation are investigated. Both damping and finite-lifetime effects of molecular-electronic excitations as well as the characteristic fourth-power enhancement of the molecular Raman scattering intensity are elucidated from first principles. It is demonstrated that the presented theory reduces to previous models of surface-enhanced Raman scattering and leads naturally to a semiclassical picture of the response of a quantum-mechanical molecular system interacting with a spatially anisotropic classical metal particle with electronic polarization approximated by a discretized collection of electric dipoles.

  3. Realignment-enhanced coherent anti-Stokes Raman scattering (CARS) and three-dimensional imaging in anisotropic fluids

    E-Print Network [OSTI]

    A. V. Kachynski; A. N. Kuzmin; P. N. Prasad; I. I. Smalyukh

    2008-07-04T23:59:59.000Z

    We apply coherent anti-Stokes Raman Scattering (CARS) microscopy to characterize director structures in liquid crystals.

  4. Molecular dynamics in liquid cyclopropane. Raman and magnetic nuclear resonance studies

    E-Print Network [OSTI]

    Boyer, Edmond

    723 Molecular dynamics in liquid cyclopropane. II. 2014 Raman and magnetic nuclear resonance as a function of temperature (155, 300 K) and pressure (up to 3 kilobars). 13C and 2H nuclear magnetic resonance experiments are performed in the same temperature range. The isotropic and anisotropic Raman profiles

  5. Breaking the Stokesanti-Stokes symmetry in Raman heterodyne detection of magnetic-resonance transitions

    E-Print Network [OSTI]

    Suter, Dieter

    is the source of the Raman field. The Raman wave is phase locked to the excit- ing laser field heterodyne detection, using the excitation laser as the local oscillator. In this case, the two sidebands that contains a coherent excitation. Figure 1 schematically shows the simplest quantum-mechanical system

  6. Noise suppression and enhanced focusability in plasma Raman amplifier with multi-frequency pump

    E-Print Network [OSTI]

    Noise suppression and enhanced focusability in plasma Raman amplifier with multi-frequency pump A. Fisch Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 and Department of Astrophysical Laser pulse compression­amplification through Raman backscattering in plasmas can be facilitated

  7. Laser-Scanning Coherent Anti-Stokes Raman Scattering Microscopy and Applications to Cell Biology

    E-Print Network [OSTI]

    Xie, Xiaoliang Sunney

    Laser-Scanning Coherent Anti-Stokes Raman Scattering Microscopy and Applications to Cell Biology Ji 11747-3157 USA ABSTRACT Laser-scanning coherent anti-Stokes Raman scattering (CARS) microscopy with fast., 1990). Duncan et al. constructed the first CARS microscope by use of two dye laser beams

  8. Molecular Resonance Raman and Rayleigh Scattering Stimulated by a Short Laser Pulse

    E-Print Network [OSTI]

    Hagedorn, George A.

    Molecular Resonance Raman and Rayleigh Scattering Stimulated by a Short Laser Pulse George A.S.A. May 9, 2013 Abstract We study a simple model for a molecule subjected to a short laser pulse. We resonance Rayleigh and Raman scattering amplitudes for a molecular system subjected to a short laser pulse

  9. Development of a nanosecond-laser-pumped Raman amplifier for short laser pulses in plasma

    E-Print Network [OSTI]

    Development of a nanosecond-laser-pumped Raman amplifier for short laser pulses in plasma Y. Ping,1 Raman amplification of short laser pulses in a plasma was proposed a decade ago in order to reach of solid-state optics. The amplifica- tion of short laser pulses is achieved by energy transfer from a long

  10. UV Resonance Raman-Selective Amide Vibrational Enhancement: Quantitative Methodology for Determining Protein Secondary Structure

    E-Print Network [OSTI]

    Asher, Sanford A.

    UV Resonance Raman-Selective Amide Vibrational Enhancement: Quantitative Methodology secondary structures, using UV resonance Raman spectroscopy (UVRRS) excited with a 206.5-nm CW laser changes in secondary structure in the protein, such as R-helix melting, while changes in the aromatic

  11. Determination of substrate pinning in epitaxial and supported graphene layers via Raman scattering

    E-Print Network [OSTI]

    Ferralis, Nicola

    The temperature-induced shift of the Raman G line in epitaxial graphene on SiC and Ni surfaces, as well as in graphene supported on SiO[subscript 2], is investigated with Raman spectroscopy. The thermal shift rate of ...

  12. Raman studies of corrosion layers formed on archaeological irons in various media

    E-Print Network [OSTI]

    147 Raman studies of corrosion layers formed on archaeological irons in various media Ludovic mandana.saheb@cea.fr, f philippe.dillmann@cea.fr Keywords: Raman spectroscopy, iron corrosion, ancient artefact, imaging. Abstract. The description and identification of corrosion products formed

  13. Quantum noise in optical fibers. II. Raman jitter in soliton communications

    E-Print Network [OSTI]

    Queensland, University of

    Quantum noise in optical fibers. II. Raman jitter in soliton communications J. F. Corney Department source of jitter and other perturbations than the gain-related Gordon­Haus noise for short pulses ( 1 ps), assuming typical fiber pa- rameters. The size of the Raman timing jitter is evaluated for both bright

  14. Indian Academy of Sciences C V Raman Avenue, Sadashivanagar, Bangalore 560 080

    E-Print Network [OSTI]

    Joshi, Yogesh Moreshwar

    Indian Academy of Sciences C V Raman Avenue, Sadashivanagar, Bangalore 560 080 The Academy or email before 20 December 2013 to: The Executive Secretary Indian Academy of Sciences C V Raman Avenue: 1. The Academy reserves the right to restrict the number of candidates for interview to a reasonable

  15. Numerical Procedure to Extract Physical Properties from Raman Scattering Data in a Flow Reactor

    E-Print Network [OSTI]

    Anderson, Timothy J.

    Numerical Procedure to Extract Physical Properties from Raman Scattering Data in a Flow Reactor in an up-flow cold-wall CVD reactor was monitored using in situ Raman spectroscopy. A two-dimensional axisymmetric model of the reactor was developed and combined with genetic and simplex algorithms for property

  16. ULTRAINTENSE AND ULTRASHORT LASER PULSES FROM RAMAN AMPLIFICATION IN PLASMA FOR LASER-PLASMA ACCELERATORS

    E-Print Network [OSTI]

    Wurtele, Jonathan

    to be a promising alternative for obtaining ultra-powerful peta-watt laser pulses. Issues in the system are the kiULTRAINTENSE AND ULTRASHORT LASER PULSES FROM RAMAN AMPLIFICATION IN PLASMA FOR LASER trapping effect in the Raman pulse amplification in plasma. An ultraintense and ultrashort laser pulse

  17. Investigation of stimulated raman scattering using short-pulse diffraction limited laser beam near the instability threshold

    SciTech Connect (OSTI)

    Kline, John L [Los Alamos National Laboratory; Montgomery, David S [Los Alamos National Laboratory; Flippo, Kirk A [Los Alamos National Laboratory; Rose, Harvey A [Los Alamos National Laboratory; Yin, L [Los Alamos National Laboratory; Albright, B J [Los Alamos National Laboratory; Johnson, R P [Los Alamos National Laboratory; Shimada, T [Los Alamos National Laboratory; Bowers, K [Los Alamos National Laboratory; Rousseaux, C [CEA; Tassin, V [CEA; Baton, S D [FRANCE; Amiranoff, F [FRANCE; Hardin, R A [WEST VIRGINIA UNIV

    2008-01-01T23:59:59.000Z

    Short pulse laser plasma interaction experiments using diffraction limited beams provide an excellent platform to investigate the fundamental physics of Stimulated Raman Scattering. Detailed understanding of these laser plasma instabilities impacts the current inertial confinement fusion ignition designs and could potentially impact fast ignition when higher energy lasers are used with longer pulse durations ( > 1 kJ and> 1 ps). Using short laser pulses, experiments can be modeled over the entire interaction time of the laser using particle-in-cell codes to validate our understanding quantitatively. Experiments have been conducted at the Trident laser facility and the LULI (Laboratoire pour l'Utilisation des Lasers Intenses) to investigate stimulated Raman scattering near the threshold of the instability using 527 nm and 1059 nm laser light respectively with 1.5-3.0 ps pulses. In both experiments, the interaction beam was focused into a pre-ionized He gas-jet plasma. Measurements of the reflectivity as a function of intensity and k{lambda}{sub D} were completed at the Trident laser facility. At LULI, a 300 fs Thomson scattering probe is used to directly measure the density fluctuations of the driven electron plasma and ion acoustic waves. Work is currently underway comparing the results of the experiments with simulations using the VPIC [K. J. Bowers, et at., Phys. Plasmas, 15 055703 (2008)] particle-in-cell code. Details of the experimental results are presented in this manuscript.

  18. Monitoring of tritium purity during long-term circulation in the KATRIN test experiment LOOPINO using laser Raman spectroscopy

    E-Print Network [OSTI]

    Fischer, Sebastian; Schlösser, Magnus; Bornschein, Beate; Drexlin, Guido; Priester, Florian; Lewis, Richard J; Telle, Helmut H

    2012-01-01T23:59:59.000Z

    The gas circulation loop LOOPINO has been set up and commissioned at Tritium Laboratory Karlsruhe (TLK) to perform Raman measurements of circulating tritium mixtures under conditions similar to the inner loop system of the neutrino-mass experiment KATRIN, which is currently under construction. A custom-made interface is used to connect the tritium containing measurement cell, located inside a glove box, with the Raman setup standing on the outside. A tritium sample (purity > 95%, 20 kPa total pressure) was circulated in LOOPINO for more than three weeks with a total throughput of 770 g of tritium. Compositional changes in the sample and the formation of tritiated and deuterated methanes CT_(4-n)X_n (X=H,D; n=0,1) were observed. Both effects are caused by hydrogen isotope exchange reactions and gas-wall interactions, due to tritium {\\beta} decay. A precision of 0.1% was achieved for the monitoring of the T_2 Q_1-branch, which fulfills the requirements for the KATRIN experiment and demonstrates the feasibility ...

  19. 785 nm Raman Spectroscopy of CVD Diamond Films Paul William May, James A Smith, and Keith N Rosser

    E-Print Network [OSTI]

    Bristol, University of

    . Here, we report that when using 785 nm excitation, the Raman spectra from thin polycrystalline diamond785 nm Raman Spectroscopy of CVD Diamond Films Paul William May, James A Smith, and Keith N Rosser Raman spectroscopy is a powerful technique often used to study CVD diamond films, however, very little

  20. Pump side scattering in ultrapowerful backward Raman amplifiers A. A. Solodov, V. M. Malkin, and N. J. Fisch

    E-Print Network [OSTI]

    Pump side scattering in ultrapowerful backward Raman amplifiers A. A. Solodov, V. M. Malkin, and N of a laser pump by plasma noise might be suppressed by an appropriate detuning of the Raman resonance, even scattering of laser pumps by plasma noise in backward Raman amplifiers. Though its growth rate is smaller

  1. The effect of substrates on the Raman spectrum of graphene: Graphene-on-sapphire and graphene-on-glass

    E-Print Network [OSTI]

    The effect of substrates on the Raman spectrum of graphene: Graphene- on-sapphire and graphene The authors investigated the influence of substrates on Raman scattering spectrum from graphene. The room-temperature Raman signatures from graphene layers on GaAs, sapphire, and glass substrates were compared with those

  2. Raman Spectroscopy Determination of Hole Concentration in p-Type GaSb

    SciTech Connect (OSTI)

    Maslar JE, Hurst WS, Wang CA

    2007-04-05T23:59:59.000Z

    Room temperature p-type GaSb bulk coupled mode spectra were measured as a function of hole concentration. These spectra were obtained using an optical system based on 752.55 nm excitation in order to obtain more sensitivity to bulk GaSb coupled mode scattering than possible with visible wavelength excitation-based systems. A relatively simple spectral model for the electronic contribution to the dielectric function was evaluated for determination of hole concentration from the bulk coupled mode spectra. Optically-derived values for hole concentration were determined by minimizing the sum of the residuals squared between an experimental and simulated spectrum as a function of total hole concentration and a plasmon damping parameter. Hole concentrations obtained from the Raman spectroscopic measurements deviated from the values determined from single field Hall effect measurements that were corrected to account for two band conduction by {approx}20% to {approx}65%. These deviations were attributed to the limitations of the spectral model employed and uncertainties in GaSb materials properties.

  3. Continuous Profiles of Cloud Microphysical Properties for the Fixed Atmospheric Radiation Measurement Sites

    SciTech Connect (OSTI)

    Jensen, M; Jensen, K

    2006-06-01T23:59:59.000Z

    The Atmospheric Radiation Measurement (ARM) Program defined a specific metric for the third quarter of Fiscal Year 2006 to produce and refine a one-year continuous time series of cloud microphysical properties based on cloud radar measurements for each of the fixed ARM sites. To accomplish this metric, we used a combination of recently developed algorithms that interpret radar reflectivity profiles, lidar backscatter profiles, and microwave brightness temperatures into the context of the underlying cloud microphysical structure.

  4. Surface-enhanced raman optical data storage system

    DOE Patents [OSTI]

    Vo-Dinh, Tuan (Knoxville, TN)

    1994-01-01T23:59:59.000Z

    An improved Surface-Enhanced Raman Optical Data Storage System (SERODS) is disclosed. In the improved system, entities capable of existing in multiple reversible states are present on the storage device. Such entities result in changed Surface-Enhanced Raman Scattering (SERS) when localized state changes are effected in less than all of the entities. Therefore, by changing the state of entities in localized regions of a storage device, the SERS emissions in such regions will be changed. When a write-on device is controlled by a data signal, such a localized regions of changed SERS emissions will correspond to the data written on the device. The data may be read by illuminating the surface of the storage device with electromagnetic radiation of an appropriate frequency and detecting the corresponding SERS emissions. Data may be deleted by reversing the state changes of entities in regions where the data was initially written. In application, entities may be individual molecules which allows for the writing of data at the molecular level. A read/write/delete head utilizing near-field quantum techniques can provide for a write/read/delete device capable of effecting state changes in individual molecules, thus providing for the effective storage of data at the molecular level.

  5. Surface-Enhanced Raman Optical Data Storage system

    DOE Patents [OSTI]

    Vo-Dinh, T.

    1994-06-28T23:59:59.000Z

    An improved Surface-Enhanced Raman Optical Data Storage System (SERODS) is disclosed. In the improved system, entities capable of existing in multiple reversible states are present on the storage device. Such entities result in changed Surface-Enhanced Raman Scattering (SERS) when localized state changes are effected in less than all of the entities. Therefore, by changing the state of entities in localized regions of a storage device, the SERS emissions in such regions will be changed. When a write-on device is controlled by a data signal, such a localized regions of changed SERS emissions will correspond to the data written on the device. The data may be read by illuminating the surface of the storage device with electromagnetic radiation of an appropriate frequency and detecting the corresponding SERS emissions. Data may be deleted by reversing the state changes of entities in regions where the data was initially written. In application, entities may be individual molecules which allows for the writing of data at the molecular level. A read/write/delete head utilizing near-field quantum techniques can provide for a write/read/delete device capable of effecting state changes in individual molecules, thus providing for the effective storage of data at the molecular level. 18 figures.

  6. Analysis of micro-structural relaxation phenomena in laser-modified fused silica using confocal Raman microscopy

    SciTech Connect (OSTI)

    Matthews, M; Vignes, R; Cooke, J; Yang, S; Stolken, J

    2009-12-15T23:59:59.000Z

    Fused silica micro-structural changes associated with localized 10.6 {micro}m CO{sub 2} laser heating are reported. Spatially-resolved shifts in the high-frequency asymmetric stretch transverse-optic (TO) phonon mode of SiO{sub 2} were measured using confocal Raman microscopy, allowing construction of axial fictive temperature (T{sub f}) maps for various laser heating conditions. A Fourier conduction-based finite element model was employed to compute on-axis temperature-time histories, and, in conjunction with a Tool-Narayanaswamy form for structural relaxation, used to fit T{sub f}(z) profiles to extract relaxation parameters. Good agreement between the calculated and measured T{sub f} was found, yielding reasonable values for relaxation time and activation enthalpy in the laser-modified silica.

  7. Development of a Raman spectroscopy technique to detect alternate transportation fuel hydrocarbon intermediates in complex combustion environments.

    SciTech Connect (OSTI)

    Ekoto, Isaac W.; Barlow, Robert S.

    2012-12-01T23:59:59.000Z

    Spontaneous Raman spectra for important hydrocarbon fuels and combustion intermediates were recorded over a range of low-to-moderate flame temperatures using the multiscalar measurement facility located at Sandia/CA. Recorded spectra were extrapolated to higher flame temperatures and then converted into empirical spectral libraries that can readily be incorporated into existing post-processing analysis models that account for crosstalk from overlapping hydrocarbon channel signal. Performance testing of the developed libraries and reduction methods was conducted through an examination of results from well-characterized laminar reference flames, and was found to provide good agreement. The diagnostic development allows for temporally and spatially resolved flame measurements of speciated hydrocarbon concentrations whose parent is more chemically complex than methane. Such data are needed to validate increasingly complex flame simulations.

  8. Synthesis and characterization of mixed monolayer protected gold nanorods and their Raman activities

    SciTech Connect (OSTI)

    Mlambo, Mbuso [Molecular Science Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, Wits 2050 (South Africa); Nanotechnology Innovation Centre, Advanced Materials Division, Mintek, Private Bag X3015, Randburg 2125 (South Africa); Mdluli, Phumlani S.; Shumbula, Poslet; Mpelane, Siyasanga [Nanotechnology Innovation Centre, Advanced Materials Division, Mintek, Private Bag X3015, Randburg 2125 (South Africa); Moloto, Nosipho, E-mail: Nosipho.Moloto@wits.ac.za [Molecular Science Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, Wits 2050 (South Africa); Skepu, Amanda; Tshikhudo, Robert [Nanotechnology Innovation Centre, Advanced Materials Division, Mintek, Private Bag X3015, Randburg 2125 (South Africa)

    2013-10-15T23:59:59.000Z

    Graphical abstract: Gold nanorods surface functionalization. - Highlights: • Mixed monolayer protected gold nanorods. • Surface enhanced Raman spectroscopy. • HS-(CH{sub 2}){sub 11}-NHCO-coumarin as a Raman active compound. - Abstract: The cetyltrimethylammonium bromide (CTAB) gold nanorods (AuNRs) were prepared by seed-mediated route followed by the addition of a Raman active compound (HS-(CH{sub 2}){sub 11}-NHCO-coumarin) on the gold nanorods surfaces. Different stoichiometric mixtures of HS-(CH{sub 2}){sub 11}-NHCO-coumarin and HS-PEG-(CH{sub 2}){sub 11}COOH were evaluated for their Raman activities. The lowest stoichiometric ratio HS-(CH{sub 2}){sub 11}-NHCO-coumarin adsorbed on gold nanorods surface was detected and enhanced by Raman spectroscopy. The produced mixed monolayer protected gold nanorods were characterized by UV-vis spectrometer for optical properties, transmission electron microscope (TEM) for structural properties (shape and aspect ratio) and their zeta potentials (charges) were obtained from ZetaSizer to determine the stability of the produced mixed monolayer protected gold nanorods. The Raman results showed a surface enhanced Raman scattering (SERS) enhancement at the lowest stoichiometric ratio of 1% HS-(CH{sub 2}){sub 11}-NHCO-coumarin compared to high ratio of 50% HS-(CH{sub 2}){sub 11}-NHCO-coumarin on the surface of gold nanorods.

  9. Operating Regime for a Backward Raman Laser Amplifier in Preformed Plasma

    SciTech Connect (OSTI)

    Daniel S. Clark; Nathaniel J. Fisch

    2003-02-06T23:59:59.000Z

    A critical issue in the generation of ultra-intense, ultra-short laser pulses by backward Raman scattering in plasma is the stability of the pumping pulse to premature backscatter from thermal fluctuations in the preformed plasma. Malkin et al. [V.M. Malkin, et al., Phys. Rev. Lett. 84 (6):1208-1211, 2000] demonstrated that density gradients may be used to detune the Raman resonance in such a way that backscatter of the pump from thermal noise can be stabilized while useful Raman amplification persists. Here plasma conditions for which the pump is stable to thermal Raman backscatter in a homogeneous plasma and the density gradients necessary to stabilize the pump for other plasma conditions are quantified. Other ancillary constraints on a Raman amplifier are also considered to determine a specific region in the Te-he plane where Raman amplification is feasible. By determining an operability region, the degree of uncertainty in density or temperature tolerable for an experimental Raman amplifier is thus also identified. The fluid code F3D, which includes the effects of thermal fluctuations, is used to verify these analytic estimates.

  10. Probing temperature gradients within the GaN buffer layer of AlGaN/GaN high electron mobility transistors with Raman thermography

    SciTech Connect (OSTI)

    Hodges, C., E-mail: chris.hodges@bristol.ac.uk; Pomeroy, J.; Kuball, M. [H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom)

    2014-02-14T23:59:59.000Z

    We demonstrate the ability of confocal Raman thermography using a spatial filter and azimuthal polarization to probe vertical temperature gradients within the GaN buffer layer of operating AlGaN/GaN high electron mobility transistors. Temperature gradients in the GaN layer are measured by using offset focal planes to minimize the contribution from different regions of the GaN buffer. The measured temperature gradient is in good agreement with a thermal simulation treating the GaN thermal conductivity as homogeneous throughout the layer and including a low thermal conductivity nucleation layer to model the heat flow between the buffer and substrate.

  11. Temperature dependent Raman scattering studies of three dimensional topological insulators Bi{sub 2}Se{sub 3}

    SciTech Connect (OSTI)

    Irfan, Bushra; Chatterjee, Ratnamala, E-mail: rmala@physics.iitd.ac.in [Department of Physics, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India); Sahoo, Satyaprakash; Gaur, Anand P. S.; Ahmadi, Majid; Katiyar, Ram S. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931 (United States); Guinel, Maxime J.-F. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931 (United States); Department of Chemistry, College of Natural Sciences, University of Puerto Rico, P.O. Box 70377, San Juan, Puerto Rico 00936-8377 (United States)

    2014-05-07T23:59:59.000Z

    We investigate the temperature dependent (83?K?T?523?K) frequency shift of 2A{sub g}{sup 1} and 1E{sub g}{sup 2} phonon modes in the three dimensional topological insulator Bi{sub 2}Se{sub 3}, using Raman spectroscopy. The high quality single crystals of Bi{sub 2}Se{sub 3} were grown using a modified Bridgman technique and characterized by Laue diffraction and high resolution transmission electron microscopy. A significant broadening in the line shape and red-shift in the frequencies were observed with increase in temperature. Polarized Raman scattering measurement shows a strong polarization effect of A{sub g}{sup 1} and A{sub g}{sup 2} phonon modes which confirms the good quality single crystals of Bi{sub 2}Se{sub 3}. Temperature co-efficient for A{sub 1g}{sup 1},?E{sub g}{sup 2}, and A{sub 1g}{sup 2} modes was estimated to be ?1.44?×?10{sup ?2}, ?1.94?×?10{sup ?2}, and ?1.95?×?10{sup ?2}?cm{sup ?1}?K, respectively. Our results shed light on anharmonic properties of Bi{sub 2}Se{sub 3}.

  12. Analysis of Doppler Lidar Data Acquired During the Pentagon Shield Field Campaign

    SciTech Connect (OSTI)

    Newsom, Rob K.

    2011-04-14T23:59:59.000Z

    Observations from two coherent Doppler lidars deployed during the Pentagon Shield field campaign are analyzed in conjunction with other sensors to characterize the overall boundary-layer structure, and identify the dominant flow characteristics during the entire two-week field campaign. Convective boundary layer (CBL) heights and cloud base heights (CBH) are estimated from an analysis of the lidar signal-to-noise-ratio (SNR), and mean wind profiles are computed using a modified velocity-azimuth-display (VAD) algorithm. Three-dimensional wind field retrievals are computed from coordinated overlapping volume scans, and the results are analyzed by visualizing the flow in horizontal and vertical cross sections. The VAD winds show that southerly flows dominate during the two-week field campaign. Low-level jets (LLJ) were evident on all but two of the nights during the field campaign. The LLJs tended to form a couple hours after sunset and reach maximum strength between 03 and 07 UTC. The surface friction velocities show distinct local maxima during four nights when strong LLJs formed. Estimates of the convective boundary layer height and residual layer height are obtained through an analysis of the vertical gradient of the lidar signal-to-noise-ratio (SNR). Strong minimum in the SNR gradient often develops just above the surface after sunrise. This minimum is associated with the developing CBL, and increases rapidly during the early portion of the daytime period. On several days, this minimum continues to increase until about sunset. Secondary minima in the SNR gradient were also observed at higher altitudes, and are believed to be remnants of the CBL height from previous days, i.e. the residual layer height. The dual-Doppler analysis technique used in this study makes use of hourly averaged radial velocity data to produce three-dimensional grids of the horizontal velocity components, and the horizontal velocity variance. Visualization of horizontal and vertical cross sections of the dual-Doppler wind retrievals often indicated a jet-like flow feature over the Potomac River under southerly flow conditions. This linear flow feature is roughly aligned with the Potomac River corridor to the south of the confluence with the Anatostia River, and is most apparent at low levels (i.e. below ~150 m MSL). It is believed that this flow arises due to reduced drag over the water surface and when the large scale flow aligns with the Potomac River corridor. A so-called area-constrained VAD analysis generally confirmed the observations from the dual-Doppler analysis. When the large scale flow is southerly, wind speeds over the Potomac River are consistently larger than the at a site just to the west of the river for altitudes less than 100 m MSL. Above this level, the trend is somewhat less obvious. The data suggest that the depth of the wind speed maximum may be reduced by strong directional shear aloft.

  13. Raman shifted third harmonic generation of upper hybrid radiation in a plasma

    SciTech Connect (OSTI)

    Magesh Kumar, K.K.; Singh, Ranjeet; Tripathi, V. K. [Department of Physics, Indian Institute of Technology Delhi, New Delhi-110016 (India)

    2012-11-15T23:59:59.000Z

    Raman shifted third harmonic generation of upper hybrid radiation is proposed and studied. In the presence of ambient magnetic field, the plasma wave present in the system produces electron density ripple (perturbation) which couples with the velocity imparted by the nonlinear ponderomotive force at twice the laser frequency producing the Raman shifted third harmonic field. The wave vector of the plasma wave provides the uncompensated momentum necessary for phase matching condition. The applied magnetic field can be adjusted to have the phase matching for the given plasma frequency. The energy conversion ratio from pump to the Raman shifted third harmonic generation of upper hybrid radiation is analyzed.

  14. Third harmonic stimulated Raman backscattering of laser in a magnetized plasma

    SciTech Connect (OSTI)

    Paknezhad, Alireza [Physics Department, Shabestar Branch, Islamic Azad University, Shabestar (Iran, Islamic Republic of)] [Physics Department, Shabestar Branch, Islamic Azad University, Shabestar (Iran, Islamic Republic of); Dorranian, Davoud [Laser Lab., Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)] [Laser Lab., Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2013-09-15T23:59:59.000Z

    This article studies the nonlinear Raman shifted third harmonic backscattering of an intense extraordinary laser wave through a homogenous transversely magnetized cold plasma. Due to the relativistic nonlinearity, the plasma dynamic is modified in the presence of transversely magnetic field, and this can generate the third harmonic scattered wave and an electrostatic upper hybrid wave via the Raman scattering process. Using the nonlinear wave equation, the mechanism of nonlinear third harmonic Raman scattering is discussed in detail to obtain the maximum growth rate of instability in the mildly relativistic regime. The growth rate decreases as the static magnetic field increases. It also increases with the pump wave amplitude.

  15. Fiber optic probe for light scattering measurements

    DOE Patents [OSTI]

    Nave, Stanley E. (Evans, GA); Livingston, Ronald R. (Aiken, SC); Prather, William S. (Augusta, GA)

    1995-01-01T23:59:59.000Z

    A fiber optic probe and a method for using the probe for light scattering analyses of a sample. The probe includes a probe body with an inlet for admitting a sample into an interior sample chamber, a first optical fiber for transmitting light from a source into the chamber, and a second optical fiber for transmitting light to a detector such as a spectrophotometer. The interior surface of the probe carries a coating that substantially prevents non-scattered light from reaching the second fiber. The probe is placed in a region where the presence and concentration of an analyte of interest are to be detected, and a sample is admitted into the chamber. Exciting light is transmitted into the sample chamber by the first fiber, where the light interacts with the sample to produce Raman-scattered light. At least some of the Raman-scattered light is received by the second fiber and transmitted to the detector for analysis. Two Raman spectra are measured, at different pressures. The first spectrum is subtracted from the second to remove background effects, and the resulting sample Raman spectrum is compared to a set of stored library spectra to determine the presence and concentration of the analyte.

  16. Fiber optic probe for light scattering measurements

    DOE Patents [OSTI]

    Nave, S.E.; Livingston, R.R.; Prather, W.S.

    1993-01-01T23:59:59.000Z

    This invention is comprised of a fiber optic probe and a method for using the probe for light scattering analyses of a sample. The probe includes a probe body with an inlet for admitting a sample into an interior sample chamber, a first optical fiber for transmitting light from a source into the chamber, and a second optical fiber for transmitting light to a detector such as a spectrophotometer. The interior surface of the probe carries a coating that substantially prevents non-scattered light from reaching the second fiber. The probe is placed in a region where the presence and concentration of an analyte of interest are to be detected, and a sample is admitted into the chamber. Exciting light is transmitted into the sample chamber by the first fiber, where the light interacts with the sample to produce Raman-scattered light. At least some of the Raman- scattered light is received by the second fiber and transmitted to the detector for analysis. Two Raman spectra are measured, at different pressures. The first spectrum is subtracted from the second to remove background effects, and the resulting sample Raman spectrum is compared to a set of stored library spectra to determine the presence and concentration of the analyte.

  17. Non-Hermitian shortcut to stimulated Raman adiabatic passage

    E-Print Network [OSTI]

    Boyan T. Torosov; Giuseppe Della Valle; Stefano Longhi

    2014-05-29T23:59:59.000Z

    We propose a non-Hermitian generalization of stimulated Raman adiabatic passage (STIRAP), which allows one to increase speed and fidelity of the adiabatic passage. This is done by adding balanced imaginary (gain/loss) terms in the diagonal (bare energy) terms of the Hamiltonian and choosing them such that they cancel exactly the nonadiabatic couplings, providing in this way an effective shortcut to adiabaticity. Remarkably, for a STIRAP using delayed Gaussian-shaped pulses in the counter-intuitive scheme the imaginary terms of the Hamiltonian turn out to be time independent. A possible physical realization of non-Hermitian STIRAP, based on light transfer in three evanescently-coupled optical waveguides, is proposed.

  18. Multiphonon resonant Raman scattering in MoS{sub 2}

    SciTech Connect (OSTI)

    Go?asa, K., E-mail: Katarzyna.Golasa@fuw.edu.pl; Grzeszczyk, M.; Wysmo?ek, A.; Babi?ski, A. [Faculty of Physics, University of Warsaw, ul. Ho?a 69, 00-681 Warszawa (Poland); Leszczy?ski, P.; Faugeras, C.; Nicolet, A. A. L.; Potemski, M. [Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble (France)

    2014-03-03T23:59:59.000Z

    Optical emission spectrum of a resonantly (??=?632.8?nm) excited molybdenum disulfide (MoS{sub 2}) is studied at liquid helium temperature. More than 20 peaks in the energy range spanning up to 1400?cm{sup ?1} from the laser line, which are related to multiphonon resonant Raman scattering processes, are observed. The attribution of the observed lines involving basic lattice vibrational modes of MoS{sub 2} and both the longitudinal (LA(M)) and the transverse (TA(M) and/or ZA(M)) acoustic phonons from the vicinity of the high-symmetry M point of the MoS{sub 2} Brillouin zone is proposed.

  19. Q-branch Raman scattering and modern kinetic thoery

    SciTech Connect (OSTI)

    Monchick, L. [The Johns Hopkins Univ., Laurel, MD (United States)

    1993-12-01T23:59:59.000Z

    The program is an extension of previous APL work whose general aim was to calculate line shapes of nearly resonant isolated line transitions with solutions of a popular quantum kinetic equation-the Waldmann-Snider equation-using well known advanced solution techniques developed for the classical Boltzmann equation. The advanced techniques explored have been a BGK type approximation, which is termed the Generalized Hess Method (GHM), and conversion of the collision operator to a block diagonal matrix of symmetric collision kernels which then can be approximated by discrete ordinate methods. The latter method, which is termed the Collision Kernel method (CC), is capable of the highest accuracy and has been used quite successfully for Q-branch Raman scattering. The GHM method, not quite as accurate, is applicable over a wider range of pressures and has proven quite useful.

  20. Detection of volatile organic compounds using surface enhanced Raman scattering

    SciTech Connect (OSTI)

    Chang, A S; Maiti, A; Ileri, N; Bora, M; Larson, C C; Britten, J A; Bond, T C

    2012-03-22T23:59:59.000Z

    The authors present the detection of volatile organic compounds directly in their vapor phase by surface-enhanced Raman scattering (SERS) substrates based on lithographically-defined two-dimensional rectangular array of nanopillars. The type of nanopillars is known as the tapered pillars. For the tapered pillars, SERS enhancement arises from the nanofocusing effect due to the sharp tip on top. SERS experiments were carried out on these substrates using various concentrations of toluene vapor. The results show that SERS signal from a toluene vapor concentration of ppm level can be achieved, and the toluene vapor can be detected within minutes of exposing the SERS substrate to the vapor. A simple adsorption model is developed which gives results matching the experimental data. The results also show promising potential for the use of these substrates in environmental monitoring of gases and vapors.

  1. Characterizing the Vertical Distribution of Aerosols Over the ARM SGP Site

    SciTech Connect (OSTI)

    Richard Ferrare, Connor Flynn, David Turner

    2009-05-05T23:59:59.000Z

    This project focused on: 1) evaluating the performance of the DOE ARM SGP Raman lidar system in measuring profiles of water vapor and aerosols, and 2) the use of the Raman lidar measurements of aerosol and water vapor profiles for assessing the vertical distribution of aerosols and water vapor simulated by global transport models and examining diurnal variability of aerosols and water vapor. The highest aerosol extinction was generally observed close to the surface during the nighttime just prior to sunrise. The high values of aerosol extinction are most likely associated with increased scattering by hygroscopic aerosols, since the corresponding average relative humidity values were above 70%. After sunrise, relative humidity and aerosol extinction below 500 m decreased with the growth in the daytime convective boundary layer. The largest aerosol extinction for altitudes above 1 km occurred during the early afternoon most likely as a result of the increase in relative humidity. The water vapor mixing ratio profiles generally showed smaller variations with altitude between day and night. We also compared simultaneous measurements of relative humidity, aerosol extinction, and aerosol optical thickness derived from the ARM SGP Raman lidar and in situ instruments on board a small aircraft flown routinely over the ARM SGP site. In contrast, the differences between the CARL and IAP aerosol extinction measurements are considerably larger. Aerosol extinction derived from the IAP measurements is, on average, about 30-40% less than values derived from the Raman lidar. The reasons for this difference are not clear, but may be related to the corrections for supermicron scattering and relative humidity that were applied to the IAP data. The investigators on this project helped to set up a major field mission (2003 Aerosol IOP) over the DOE ARM SGP site. One of the goals of the mission was to further evaluate the aerosol and water vapor retrievals from this lidar system. Analysis of the aerosol and water vapor data collected by the Raman lidar during the 2003 Aerosol IOP indicated that the sensitivity of the lidar was significantly lower than when the lidar was initially deployed. A detailed analysis after the IOP of the long-term dataset demonstrated that the lidar began degrading in early 2002, and that it lost approximately a factor of 4 in sensitivity between 2002 and 2004. We participated in the development of the remediation plan for the system to restore its initial performance. We conducted this refurbishment and upgrade from May- September 2004. This remediation lead to an increase in the signal-to-noise ratio of 10 and 30 for the Raman lidar's water vapor mixing ratio and aerosol backscatter coefficient data, respectively as compared to the signal strengths when the system was first deployed. The DOE ARM Aerosol Lidar Validation Experiment (ALIVE), which was conducted during September 2005, evaluated the impact of these modifications and upgrades on the SGP Raman lidar measurements of aerosol extinction and optical thickness. The CARL modifications significantly improved the accuracy and temporal resolution of the aerosol measurements. Aerosol extinction profiles measured by the Raman lidar were also used to evaluate aerosol extinction profiles and aerosol optical thickness (AOT) simulated by aerosol models as part of the Aerosol module inter-Comparison in global models (AEROCOM) (http://nansen.ipsl.jussieu.fr/AEROCOM/aerocomhome.html) project. There was a wide range in how the models represent the aerosol extinction profiles over the ARM SGP site, even though the average annual AOT represented by the various models and measured by CARL and the Sun photometer were in general agreement, at least within the standard deviations of the averages. There were considerable differences in the average vertical distributions among the models, even among models that had similar average aerosol optical thickness. Deviations between mean aerosol extinction profiles were generally small (~20-30%) for altitudes above 2 km, and grew consider

  2. A review of "Framing ‘India’: The Colonial Imaginary in Early Modern Culture." by Shankar Raman

    E-Print Network [OSTI]

    Nagendra Rao

    2003-01-01T23:59:59.000Z

    and relatively autonomous historical conditions pre- vailing in early modern Europe? (4). Raman argues that from antiquity onwards India functioned as an important boundary through and against which Christian Europe constructed distinc- tive forms of identity...

  3. Detection of bacterial endospores by means of ultrafast coherent raman spectroscopy 

    E-Print Network [OSTI]

    Pestov, Dmitry Sergeyevich

    2008-10-10T23:59:59.000Z

    This work is devoted to formulation and development of a laser spectroscopic technique for rapid detection of biohazards, such as Bacillus anthracis spores. Coherent anti-Stokes Raman scattering (CARS) is used as an underlying process for active...

  4. Detection of bacterial endospores by means of ultrafast coherent raman spectroscopy

    E-Print Network [OSTI]

    Pestov, Dmitry Sergeyevich

    2008-10-10T23:59:59.000Z

    This work is devoted to formulation and development of a laser spectroscopic technique for rapid detection of biohazards, such as Bacillus anthracis spores. Coherent anti-Stokes Raman scattering (CARS) is used as an underlying process for active...

  5. Uniaxial strain in graphene by Raman spectroscopy: G peak splitting, Grüneisen parameters, and sample orientation

    E-Print Network [OSTI]

    Mohiuddin, T. M. G.

    We uncover the constitutive relation of graphene and probe the physics of its optical phonons by studying its Raman spectrum as a function of uniaxial strain. We find that the doubly degenerate E[subscript 2g] optical mode ...

  6. Double resonance Raman spectra of graphene : a full 2D calculation

    E-Print Network [OSTI]

    Narula, Rohit

    2007-01-01T23:59:59.000Z

    Visible range Raman spectra of graphene are generated based on the double resonant process employing a full two-dimensional numerical calculation applying second-order perturbation theory. Tight binding expressions for ...

  7. Raman Spectroscopy as a Probe of Surface Oxides and Hydrides on Niobium

    SciTech Connect (OSTI)

    J. Zasadzinski, B. Albee, S. Bishnoi, C. Cao, G. Ciovati, L.D. Cooley, D.C. Ford, Th. Proslier

    2011-07-01T23:59:59.000Z

    Raman microscopy/spectroscopy has been used in conjunction with AFM, tunneling and magnetic susceptibility to identify surface oxides and hydrides on annealed, recrystallized foils of high purity Nb and on single crystals of cavity grade Nb. Cold worked regions of the Nb foil as well as rough regions near grain boundaries showed clear evidence of ordered hydride phases which were identified by VASP phonon calculations. Cold worked regions also displayed enhanced surface paramagnetism. Surface enhanced Raman spectra have also been obtained using 1.0 nm Au depositon. The SERS spectra reveal hydride molecular species which are not observable by conventional Raman. These results indicate that Raman is a useful probe of Nb surfaces relevant for cavity performance

  8. Development of a Surface Enhanced Raman Spectroscopy Platform Technology to Detect Cardiac Biomarkers of Myocardial Infarction 

    E-Print Network [OSTI]

    Benford, Melodie Elane

    2013-04-24T23:59:59.000Z

    to include cardiac markers as central to diagnosis. To address this clinical need, a sensitive microfluidic surface-enhanced Raman spectroscopy (SERS) nanochannel-based optical device is being developed for ultimate use as a point-of-care device...

  9. Solar Energy Materials & Solar Cells 71 (2002) 511522 In situ Raman spectroscopy of the

    E-Print Network [OSTI]

    Nabben, Reinhard

    Solar Energy Materials & Solar Cells 71 (2002) 511­522 In situ Raman spectroscopy. In this situation, a low energy excitation (e.g. visible light) is needed to excite an electron to a neighboring

  10. Integration of Raman Spectroscopy and Cone Penetration Technology Characterize Chlorinated Hydrocarbon Contaminant Plumes

    SciTech Connect (OSTI)

    Rossabi, J.

    1998-11-18T23:59:59.000Z

    The goal of the project was the development and integration of a Raman spectroscopy unit with a Cone Penetration Technologies (CPT) system for use in locating contamination below the ground surface.

  11. Beyond Myopic Inference in Big Data Pipelines Karthik Raman, Adith Swaminathan, Johannes Gehrke, Thorsten Joachims

    E-Print Network [OSTI]

    Joachims, Thorsten

    ]: Learning General Terms Algorithms, Experimentation, Theory Keywords Big Data Pipelines, Modular Design Detection & Recognition pipeline. creation, model construction, testing, and visualization. In orderBeyond Myopic Inference in Big Data Pipelines Karthik Raman, Adith Swaminathan, Johannes Gehrke

  12. Tip-Enhanced Near-Field Raman Spectroscopy Probing Single Dye...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    was used to characterize an interfacial electron transfer system of dye-sensitized titanium oxide (TiO2) nanoparticles. We have obtained the near-field Raman spectra that are...

  13. Zone folding effect in Raman G-band intensity of twisted bilayer graphene

    E-Print Network [OSTI]

    Dresselhaus, Mildred

    The G-band Raman intensity is calculated for twisted bilayer graphene as a function of laser excitation energy based on the extended tight binding method. Here we explicitly consider the electron-photon and electron-phonon ...

  14. Vlasov simulations of kinetic enhancement of Raman backscatter in laser fusion plasmas

    E-Print Network [OSTI]

    Strozzi, D. J. (David J.)

    2006-01-01T23:59:59.000Z

    Stimulated Raman scattering (SRS) is studied in plasmas relevant to inertial confinement fusion (ICF). The Eulerian Vlasov-Maxwell code ELVIS was developed and run for this purpose. Plasma waves are heavily Landau damped ...

  15. Mapping residual stress fields from Vickers hardness indents using Raman microprobe spectroscopy

    SciTech Connect (OSTI)

    Sparks, R.G.; Enloe, W.S.; Paesler, M.A.

    1988-12-01T23:59:59.000Z

    Micro-Raman spectroscopy is used to map the residual stress fields in the vicinity of Vickers hardness indents. Both 514.5 and 488.0 nm, light is used to excite the effect and the resulting shifted and broadened Raman peaks are analyzed using computer deconvolution. Half-wave plates are used to vary the orientation of the incident later light`s polarization state with respect to crystal orientation. The Raman scattered light is then analyzed for polarization dependences which are indicative of the various components of the Raman scattering tensor. Such studies can yield valuable information about the orientation of stress components in a well known stress field. The results can then be applied to the determination of stress components in machined semiconductor materials.

  16. Diradicals acting through diamagnetic phenylene vinylene bridges: Raman spectroscopy as a probe to characterize spin delocalization

    SciTech Connect (OSTI)

    González, Sandra Rodríguez; Nieto-Ortega, Belén; González Cano, Rafael C.; López Navarrete, Juan T., E-mail: vecianaj@icmab.es, E-mail: teodomiro@uma.es, E-mail: casado@uma.es; Casado, Juan, E-mail: vecianaj@icmab.es, E-mail: teodomiro@uma.es, E-mail: casado@uma.es [Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071 (Spain)] [Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071 (Spain); Lloveras, Vega; Vidal-Gancedo, José; Rovira, Concepció; Veciana, Jaume, E-mail: vecianaj@icmab.es, E-mail: teodomiro@uma.es, E-mail: casado@uma.es [Department of Molecular Nanoscience and Organic Materials, Institut de Ciència de Materials de Barcelona (CSIC), Campus Universitari de Bellaterra, E-08193 Cerdanyola, Barcelona (Spain) [Department of Molecular Nanoscience and Organic Materials, Institut de Ciència de Materials de Barcelona (CSIC), Campus Universitari de Bellaterra, E-08193 Cerdanyola, Barcelona (Spain); NANOMOL group, Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Campus Universitari de Bellaterra, E-08193 Cerdanyola, Barcelona (Spain); Novoa, Juan J.; Mota, Fernando [Dpt. de Química Física and IQTCUB, Fac. Química, Univ. de Barcelona, Av. Diagonal, 647, 08028-Barcelona (Spain)] [Dpt. de Química Física and IQTCUB, Fac. Química, Univ. de Barcelona, Av. Diagonal, 647, 08028-Barcelona (Spain); Corro, Elena del; Taravillo, Mercedes; Baonza, Valentín G. [MALTA-Consolider Team, Department of Physical Chemistry, University Complutense of Madrid, Madrid 28040 (Spain)] [MALTA-Consolider Team, Department of Physical Chemistry, University Complutense of Madrid, Madrid 28040 (Spain)

    2014-04-28T23:59:59.000Z

    We present a complete Raman spectroscopic study in two structurally well-defined diradical species of different lengths incorporating oligo p-phenylene vinylene bridges between two polychlorinated triphenylmethyl radical units, a disposition that allows sizeable conjugation between the two radicals through and with the bridge. The spectroscopic data are interpreted and supported by quantum chemical calculations. We focus the attention on the Raman frequency changes, interpretable in terms of: (i) bridge length (conjugation length); (ii) bridge conformational structure; and (iii) electronic coupling between the terminal radical units with the bridge and through the bridge, which could delineate through-bond spin polarization, or spin delocalization. These items are addressed by using the “oligomer approach” in conjunction with pressure and temperature dependent Raman spectroscopic data. In summary, we have attempted to translate the well-known strategy to study the electron (charge) structure of ??conjugated molecules by Raman spectroscopy to the case of electron (spin) interactions via the spin delocalization mechanism.

  17. Raman Spectroscopy Provides a Powerful Diagnostic Tool for Accurate Determination of Albumin Glycation

    E-Print Network [OSTI]

    Dingari, Narahara Chari

    We present the first demonstration of glycated albumin detection and quantification using Raman spectroscopy without the addition of reagents. Glycated albumin is an important marker for monitoring the long-term glycemic ...

  18. The use of Surface Enhanced Raman Spectroscopy (SERS) for biomedical applications 

    E-Print Network [OSTI]

    Chowdhury, Mustafa Habib

    2007-04-25T23:59:59.000Z

    Recent advances in nanotechnology and the biotechnology revolution have created an immense opportunity for the use of noble metal nanoparticles as Surface Enhanced Raman Spectroscopy (SERS) substrates for biological sensing and diagnostics...

  19. Spatial correlation between chemical and topological defects in vitreous silica: UV-resonance Raman study

    SciTech Connect (OSTI)

    Saito, M., E-mail: makina.saito@elettra.eu; D’Amico, F.; Bencivenga, F.; Cucini, R.; Gessini, A.; Principi, E.; Masciovecchio, C. [Elettra-Sincrotrone Trieste, S. S. 14 Km 163.5, I-34149 Trieste (Italy)

    2014-06-28T23:59:59.000Z

    A spatial correlation between chemical and topological defects in the tetrahedron network in vitreous silica produced by a fusion process of natural quartz crystals was found by synchrotron-based UV resonance Raman experiments. Furthermore, a quantitative correlation between these defects was obtained by comparing visible Raman and UV absorption spectra. These results indicate that in vitreous silica produced by the fusion process the topological defects disturb the surrounding tetrahedral silica network and induce further disorder regions with sub nanometric sizes.

  20. Dual-Remote Raman Technology for In-Situ Identification of Tank Waste - 13549

    SciTech Connect (OSTI)

    Bryan, Sam; Levitskaia, Tatiana; Lines, Amanda; Smith, Frannie; Josephson, Gary [Pacific Northwest National Laboratory, Richland WA, 99352 (United States)] [Pacific Northwest National Laboratory, Richland WA, 99352 (United States); Bello, Job [EIC, Inc., Norwood, MA 02062 (United States)] [EIC, Inc., Norwood, MA 02062 (United States)

    2013-07-01T23:59:59.000Z

    A new Raman spectroscopic system for in-situ identification of the composition of solid nuclear tank waste is being developed by collaborative effort between Pacific Northwest National Laboratory (PNNL) and EIC Laboratories, Inc. The recent advancements in Raman technology allow probing the chemical composition of the tank waste without sample collection. In the newly tested configuration, the Raman probe is installed on the top of the tank riser and sends the incident laser beam to the bottom of the tank, 10 - 70 feet away. The returning light containing chemical information is collected by the Raman probe and is transmitted via fiber optic cable to the spectrometer located outside the tank farm area. This dual remote technology significantly expands currently limited options for the safe rapid in-situ identification of the solid tank waste needed for the retrieval decisions. The developed Raman system was extensively tested for acceptability prior to tank farm deployment. This testing included calibration of the system with respect of the distance between the Raman probe and the sample, incident laser beam angle, and presence of the optical interferences. The Raman system was successfully deployed on Tank C-111 at the US DOE Hanford site. As the result of this deployment, the composition of the hardpan at the bottom of C-111 tank was identified. Further development of the dual-remote Raman technology will provide a significant safety enhancement eliminating the potential of personnel radiation exposure associated with the grab sample collection and expands options of the rapid and cost-effective in-situ chemical analysis of the tank waste. (authors)

  1. Dual-Remote Raman Technology for In-Situ Identification of Tank Waste

    SciTech Connect (OSTI)

    Bryan, Samuel A.; Levitskaia, Tatiana G.; Lines, Amanda M.; Smith, Frances N.; Josephson, Gary B.; Bello, Job M.

    2013-02-24T23:59:59.000Z

    A new Raman spectroscopic system for in-situ identification of the composition of the solid nuclear tank waste is being developed by collaborative effort between Pacific Northwest National Laboratory (PNNL) and EIC, Inc. The recent advancements in the Raman technology allow probing the chemical composition of the tank waste without sample collection. In the newly tested configuration, the Raman probe is installed on the top of the tank riser and sends the incident laser beam to the bottom of the tank, 10 – 70 feet away. The returning light containing chemical information is collected by the Raman probe and transmits it via fiber optic cable to the spectrometer located outside the tank farm area. This dual remote technology significantly expands currently limited options for the safe rapid in-situ identification of the solid tank waste needed for the retrieval decisions. The developed Raman system was extensively tested for acceptability prior tank farm deployment. This testing included calibration of the system with the respect of the distance between the Raman probe and the sample, incident laser beam angle, and presence of the optical interferences. The Raman system was successfully deployed to C-111 tank at the US DOE Hanford site. As the result of this deployment, the composition of the hardpan at the bottom of C-111 tank was identified. Further development of the dual-remote Raman technology will provide a significant safety enhancement eliminating the potential of personnel radiation exposure associated with the grab sample collection and expands options of the rapid and cost-effective in-situ chemical analysis of the tank waste.

  2. Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds

    SciTech Connect (OSTI)

    Turner, David, D.; Ferrare, Richard, A.

    2011-07-06T23:59:59.000Z

    The 'Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds' project focused extensively on the analysis and utilization of water vapor and aerosol profiles derived from the ARM Raman lidar at the Southern Great Plains ARM site. A wide range of different tasks were performed during this project, all of which improved quality of the data products derived from the lidar or advanced the understanding of atmospheric processes over the site. These activities included: upgrading the Raman lidar to improve its sensitivity; participating in field experiments to validate the lidar aerosol and water vapor retrievals; using the lidar aerosol profiles to evaluate the accuracy of the vertical distribution of aerosols in global aerosol model simulations; examining the correlation between relative humidity and aerosol extinction, and how these change, due to horizontal distance away from cumulus clouds; inferring boundary layer turbulence structure in convective boundary layers from the high-time-resolution lidar water vapor measurements; retrieving cumulus entrainment rates in boundary layer cumulus clouds; and participating in a field experiment that provided data to help validate both the entrainment rate retrievals and the turbulent profiles derived from lidar observations.

  3. Raman Spectroscopy and Microscopy of Individual Cells andCellular Components

    SciTech Connect (OSTI)

    Chan, J; Fore, S; Wachsmann-Hogiu, S; Huser, T

    2008-05-15T23:59:59.000Z

    Raman spectroscopy provides the unique opportunity to non-destructively analyze chemical concentrations on the submicron length scale in individual cells without the need for optical labels. This enables the rapid assessment of cellular biochemistry inside living cells, and it allows for their continuous analysis to determine cellular response to external events. Here, we review recent developments in the analysis of single cells, subcellular compartments, and chemical imaging based on Raman spectroscopic techniques. Spontaneous Raman spectroscopy provides for the full spectral assessment of cellular biochemistry, while coherent Raman techniques, such as coherent anti-Stokes Raman scattering is primarily used as an imaging tool comparable to confocal fluorescence microscopy. These techniques are complemented by surface-enhanced Raman spectroscopy, which provides higher sensitivity and local specificity, and also extends the techniques to chemical indicators, i.e. pH sensing. We review the strengths and weaknesses of each technique, demonstrate some of their applications and discuss their potential for future research in cell biology and biomedicine.

  4. Raman Spectroscopy of DNA Packaging in Individual Human Sperm Cells distinguishes Normal from Abnormal Cells

    SciTech Connect (OSTI)

    Huser, T; Orme, C; Hollars, C; Corzett, M; Balhorn, R

    2009-03-09T23:59:59.000Z

    Healthy human males produce sperm cells of which about 25-40% have abnormal head shapes. Increases in the percentage of sperm exhibiting aberrant sperm head morphologies have been correlated with male infertility, and biochemical studies of pooled sperm have suggested that sperm with abnormal shape may contain DNA that has not been properly repackaged by protamine during spermatid development. We have used micro-Raman spectroscopy to obtain Raman spectra from individual human sperm cells and examined how differences in the Raman spectra of sperm chromatin correlate with cell shape. We show that Raman spectra of individual sperm cells contain vibrational marker modes that can be used to assess the efficiency of DNA-packaging for each cell. Raman spectra obtained from sperm cells with normal shape provide evidence that DNA in these sperm is very efficiently packaged. We find, however, that the relative protein content per cell and DNA packaging efficiencies are distributed over a relatively wide range for sperm cells with both normal and abnormal shape. These findings indicate that single cell Raman spectroscopy should be a valuable tool in assessing the quality of sperm cells for in-vitro fertilization.

  5. A digital map of the high center (HC) and low center (LC) polygon boundaries delineated from high resolution LiDAR data for Barrow, Alaska

    SciTech Connect (OSTI)

    Gangodagamage, Chandana; Wullschleger, Stan

    2014-07-03T23:59:59.000Z

    This dataset represent a map of the high center (HC) and low center (LC) polygon boundaries delineated from high resolution LiDAR data for the arctic coastal plain at Barrow, Alaska. The polygon troughs are considered as the surface expression of the ice-wedges. The troughs are in lower elevations than the interior polygon. The trough widths were initially identified from LiDAR data, and the boundary between two polygons assumed to be located along the lowest elevations on trough widths between them.

  6. A digital map of the high center (HC) and low center (LC) polygon boundaries delineated from high resolution LiDAR data for Barrow, Alaska

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Gangodagamage, Chandana; Wullschleger, Stan

    This dataset represent a map of the high center (HC) and low center (LC) polygon boundaries delineated from high resolution LiDAR data for the arctic coastal plain at Barrow, Alaska. The polygon troughs are considered as the surface expression of the ice-wedges. The troughs are in lower elevations than the interior polygon. The trough widths were initially identified from LiDAR data, and the boundary between two polygons assumed to be located along the lowest elevations on trough widths between them.

  7. Exploring the relationships between vegetation measurements and temperature in residential areas by integrating LIDAR and remotely sensed imagery

    E-Print Network [OSTI]

    Clemonds, Matthew A

    2006-10-30T23:59:59.000Z

    at higher resolutions is much more difficult to obtain. This has allowed researchers to study urban heat island dynamics at a micro-scale. However, this study suggests that a vegetation index alone might not be the best surrogate variable for providing...

  8. GEOPHYSICAL RESEARCH LETTERS, VOL. 25, NO. 16, PAGES 3139-3142, AUGUST 15, 1998 Multiwavelength lidar aerosol measurements made at

    E-Print Network [OSTI]

    Duck, Thomas J.

    ., 1995] leading to polar stratospheric cloud (PSC) formation. Stratospheric aerosols can also serve to as P1) so only a brief overview will be given here. 1Center for Research in Earth and Space Technology) Nagoya University, Nagoya, Japan. 4Communications Research Laboratory (CRL) Tokyo, Japan. 5Meteorological

  9. Micro-Raman spectroscopic study of nanolaminated Ti{sub 5}Al{sub 2}C{sub 3}

    SciTech Connect (OSTI)

    Zhang, H.; Li, Z. J. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, X. H. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Xiang, H. M.; Zhou, Y. C, E-mail: yczhou714@gmail.com [Science and Technology of Advanced Functional Composite Laboratory, ARIMPT, No.1 South Dahongmen Road, Beijing 100076 (China)

    2014-03-31T23:59:59.000Z

    Micro-Raman spectroscopic study and lattice dynamics calculations were conducted to study a recently identified layered ternary carbide, Ti{sub 5}Al{sub 2}C{sub 3}. The experimental Raman shifts were remarkably consistent with the calculated values. Polarized Raman spectrum was collected in the polycrystalline sample, which confirmed the theoretical symmetry assignment of the Raman modes. In addition, the atomic vibrations of the peaks at 192?cm{sup ?1}, 311?cm{sup ?1}, and 660?cm{sup ?1} were identified to be the combination of the counterparts in Ti{sub 2}AlC and Ti{sub 3}AlC{sub 2}.

  10. A joint study of the lower ionosphere by radar, lidar, and spectrometer

    SciTech Connect (OSTI)

    Zhou, Qihou.

    1991-01-01T23:59:59.000Z

    The dynamics and associated phenomena occurring in the lower ionospheric-E region, especially the mesopause region between 80 km to 110 km at low latitude, are studied. In particular, incoherent scatter radar (ISR), sodium lidar and airglow spectrometry are used to study the ionospheric structure and neutral sodium structure. The simultaneous study of the ionospheric plasma and neutral atomic sodium is unprecedented in scope and detail. The joint study of the mesopause region reveals that plasma, neutral densities and temperature are interconnected through the same atmospheric dynamics. The theme of the thesis is to explain the formation of the controversial sporadic sodium layer (SSL) events. Strong correlation is established between the average total ion and sodium concentrations, and between sporadic-E and SSL events. The mechanism proposed in the thesis, which invokes temperature fluctuations induced by tides and gravity waves, finds good agreement with observations. Tides and gravity waves can converge ions into thin layers through the windshear mechanisms and can influence the concentration of atomic sodium through temperature fluctuations. Sodium abundance is shown to augment rapidly when the temperature is increased. Gravity wave theory states that the ion convergence node coincides with a temperature maximum for a westward propagating gravity wave, and coincides with a temperature minimum for an eastward propagating wave. Because tidal winds propagate westward, the ion layer coincides with the temperature maximum which consequently induces higher sodium concentration. This can account for the general correlation between sodium and total ion concentration and is supported by the O2(0-1) rotational temperature. Gravity waves and their interaction with tidal winds are believed to be responsible for the close association between sudden sodium layers and sporadic-E layers.

  11. Molecular near-field antenna effect in resonance hyper-Raman scattering: Intermolecular vibronic intensity borrowing of solvent from solute through dipole-dipole and dipole-quadrupole interactions

    SciTech Connect (OSTI)

    Shimada, Rintaro; Hamaguchi, Hiro-o, E-mail: hhama@nctu.edu.tw [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China)

    2014-05-28T23:59:59.000Z

    We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-?-carotene (?-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute ?-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of ?-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of ?-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of ?-carotene with the vibrations of a proximate solvent molecule through solute–solvent dipole–dipole and dipole–quadrupole interactions. It is shown that the infrared active modes arise from the dipole–dipole interaction, whereas Raman active modes from the dipole–quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 Å.

  12. High-pressure study of isoviolanthrone by Raman spectroscopy

    SciTech Connect (OSTI)

    Zhao, Xiao-Miao; Huang, Qiao-Wei [Department of Physics, South China University of Technology, Guangzhou 510640 (China); Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 (China); Zhang, Jiang [Department of Physics, South China University of Technology, Guangzhou 510640 (China); Zhong, Guo-Hua [Center for Photovoltaics and Solar Energy, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China); Lin, Hai-Qing [Beijing Computational Science Research Center, Beijing 100084 (China); Chen, Xiao-Jia, E-mail: xjchen@hpstar.ac.cn [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 (China); Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015 (United States)

    2014-06-28T23:59:59.000Z

    Vibrational properties of isoviolanthrone are investigated by Raman scattering at pressures up to 30.5 GPa and room temperature. A complete characterization of phonon spectra under pressure is given for this material. The onset of a phase transition at 11.0 GPa and the formation of a new phase above 13.8 GPa are identified from both the frequency shifts and the changes in the full width half maxima of the intra- and internal modes. The transition is proposed to result from the changes of intra- and intermolecular bonding. The tendencies of the intensity ratios with pressure are in good agreement with the pressure dependence of the resistance at room temperature, indicating that the phase transition may be an electronic origin. The absence of the changes in the lattice modes indicates that the observed phase transition is probably a result of the structural distortions or reorganizations. The reversible character of the transition upon compression and decompression is determined in the entire pressure region studied.

  13. Using Radar, Lidar and Radiometer Data from NSA and SHEBA to Quantify Cloud Property Effects on the Surface Heat Budget in the Arctic

    SciTech Connect (OSTI)

    Janet Intrieri; Mathhew Shupe

    2005-01-01T23:59:59.000Z

    Cloud and radiation data from two distinctly different Arctic areas are analyzed to study the differences between coastal Alaskan and open Arctic Ocean region clouds and their respective influence on the surface radiation budget. The cloud and radiation datasets were obtained from (1) the DOE North Slope of Alaska (NSA) facility in the coastal town of Barrow, Alaska, and (2) the SHEBA field program, which was conducted from an icebreaker frozen in, and drifting with, the sea-ice for one year in the Western Arctic Ocean. Radar, lidar, radiometer, and sounding measurements from both locations were used to produce annual cycles of cloud occurrence and height, atmospheric temperature and humidity, surface longwave and shortwave broadband fluxes, surface albedo, and cloud radiative forcing. In general, both regions revealed a similar annual trend of cloud occurrence fraction with minimum values in winter (60-75%) and maximum values during spring, summer and fall (80-90%). However, the annual average cloud occurrence fraction for SHEBA (76%) was lower than the 6-year average cloud occurrence at NSA (92%). Both Arctic areas also showed similar annual cycle trends of cloud forcing with clouds warming the surface through most of the year and a period of surface cooling during the summer, when cloud shading effects overwhelm cloud greenhouse effects. The greatest difference between the two regions was observed in the magnitude of the cloud cooling effect (i.e., shortwave cloud forcing), which was significantly stronger at NSA and lasted for a longer period of time than at SHEBA. This is predominantly due to the longer and stronger melt season at NSA (i.e., albedo values that are much lower coupled with Sun angles that are somewhat higher) than the melt season observed over the ice pack at SHEBA. Longwave cloud forcing values were comparable between the two sites indicating a general similarity in cloudiness and atmospheric temperature and humidity structure between the two regions.

  14. Polarised Raman measurements of -carotene in and carotene encapsulated in SWNTs

    E-Print Network [OSTI]

    Nabben, Reinhard

    Katharina Brose , Norman Tschirner , Athina Zouni , Frank Müh 1 1 2 2 , Kazuhiro Yanagi , Hiromichi Kataura: Conclusions: March 2010 katharina.brose@physik.tu-berlin.de Motivation: b-carotene in the different structures, The Netherlands 1999, Ch. 10. [3] N. Tschirner 18 The Photochemistry of Carotenoids , poster THU 38. [4] K. Brose

  15. The effects of machine parameters on residual stress determined using micro-Raman spectroscopy

    SciTech Connect (OSTI)

    Sparks, R.G.; Enloe, W.S.; Paesler, M.A.

    1988-12-01T23:59:59.000Z

    The effects of machine parameters on residual stresses in single point diamond turned silicon and germanium have been investigated using micro-Raman spectroscopy. Residual stresses were sampled across ductile feed cuts in < 100 > silicon and germanium which were single point diamond turned using a variety of feed rates, rake angles and clearance angles. High spatial resolution micro-Raman spectra (1{mu}m spot) were obtained in regions of ductile cutting where no visible surface damage was present. The use of both 514-5nm and 488.0nm excitation wavelengths, by virtue of their differing characteristic penetration depths in the materials, allowed determinations of stress profiles as a function of depth into the sample. Previous discussions have demonstrated that such Raman spectra will exhibit asymmetrically broadened peaks which are characteristic of the superposition of a continuum of Raman scatterers from the various depths probed. Depth profiles of residual stress were obtained using computer deconvolution of the resulting asymmetrically broadened raman spectra.

  16. Accurate and Approximate Calculations of Raman Scattering in the Atmosphere of Neptune

    E-Print Network [OSTI]

    Sromovsky, Lawrence

    2015-01-01T23:59:59.000Z

    Raman scattering by H$_2$ in Neptune's atmosphere has significant effects on its reflectivity for $\\lambda 0.5 $\\mu$m, producing baseline decreases of $\\sim$ 20% in a clear atmosphere and $\\sim$ 10% in a hazy atmosphere. Here we present the first radiation transfer algorithm that includes both polarization and Raman scattering and facilitates computation of spatially resolved spectra. New calculations show that Cochran and Trafton's (1978, Astrophys. J. 219, 756-762) suggestion that light reflected in the deep CH$_4$ bands is mainly Raman scattered is not valid for current estimates of the CH$_4$vertical distribution, which implies only a 4% Raman contribution. Comparisons with IUE, HST, and groundbased observations confirm that high altitude haze absorption is reducing Neptune's geometric albedo by $\\sim$6% in the 0.22-0.26 $\\mu$m range and by $\\sim$13% in the 0.35-0.45 $\\mu$m range. We used accurate calculations to evaluate several approximations of Raman scattering. The Karkoschka (1994, Icarus 111, ...

  17. Observational Studies of Atmospheric Aerosols over Bozeman, Montana, Using a Two-Color Lidar, a Water Vapor DIAL, a Solar Radiometer,

    E-Print Network [OSTI]

    Shaw, Joseph A.

    Observational Studies of Atmospheric Aerosols over Bozeman, Montana, Using a Two-Color Lidar form 24 June 2010) ABSTRACT Coordinated observational data of atmospheric aerosols were collected over-based nephelometer. The optical properties and spatial distribution of the atmospheric aerosols were inferred from

  18. SilviLaser 2011, Oct. 16-19, 2011 Hobart, Australia Towards automated and operational forest inventories with T-Lidar

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    inventories with T-Lidar A. Othmani1 , A. Piboule2 , M. Krebs3 , C. Stolz1 and L.F.C. Lew Yan Voon1 1 Cluny, France, michael.krebs@ensam.eu Keywords: terrestrial laser scanning, forest inventory, tree detection, DBH. Abstract Forest inventory automation has become a major issue in forestry. The complexity

  19. Cloud fraction, liquid and ice water contents derived from long-term radar, lidar, and microwave radiometer data are systematically compared to models to quantify and

    E-Print Network [OSTI]

    Hogan, Robin

    Cloud fraction, liquid and ice water contents derived from long-term radar, lidar, and microwave a systematic evaluation of clouds in forecast models. Clouds and their associated microphysical processes for end users of weather forecasts, who may be interested not only in cloud cover, but in other variables

  20. Evaluation of Cloud-Phase Retrieval Methods for SEVIRI on Meteosat-8 Using Ground-Based Lidar and Cloud Radar Data

    E-Print Network [OSTI]

    Stoffelen, Ad

    Evaluation of Cloud-Phase Retrieval Methods for SEVIRI on Meteosat-8 Using Ground-Based Lidar and Cloud Radar Data ERWIN L. A. WOLTERS, ROBERT A. ROEBELING, AND ARNOUT J. FEIJT Royal Netherlands 2007) ABSTRACT Three cloud-phase determination algorithms from passive satellite imagers are explored

  1. Measurement-Measurement-

    E-Print Network [OSTI]

    Jeong, Jaehoon "Paul"

    Internet Measurement- System A Measurement- System B Control System GPS Satellite GPS Satellite GPS Receiver GPS Receiver 2) measurement 3) data1) command Methodology for One-way IP Performance Measurement This paper proposes a methodology for measurement of one-way IP performance metrics such as one-way delay

  2. DOI: 10.1002/chem.201002027 Surface-Enhanced Raman Scattering of Single-and Few-Layer Graphene by

    E-Print Network [OSTI]

    Kim, Bongsoo

    DOI: 10.1002/chem.201002027 Surface-Enhanced Raman Scattering of Single- and Few-Layer Graphene*[a] Introduction Raman spectroscopy has been utilized as a powerful tool for the characterization of graphene and any defects in the graphene.[1] A Si substrate with a metal oxide layer of a specific thick- ness has

  3. 785 nm Raman spectroscopy of CVD diamond films P.W. May , J.A. Smith, K.N. Rosser

    E-Print Network [OSTI]

    Bristol, University of

    using 785 nm excitation with 1 µm spot size, the Raman spectra from thin polycrystalline diamond films785 nm Raman spectroscopy of CVD diamond films P.W. May , J.A. Smith, K.N. Rosser School is a powerful technique often used to study CVD diamond films, however, very little work has been reported

  4. THE JOURNAL OF CHEMICAL PHYSICS 135, 184202 (2011) Can stimulated Raman pumping cause large population transfers in

    E-Print Network [OSTI]

    Zare, Richard N.

    THE JOURNAL OF CHEMICAL PHYSICS 135, 184202 (2011) Can stimulated Raman pumping cause large 2011; published online 9 November 2011) When stimulated Raman pumping (SRP) is applied to a stream with the energy difference between the pump and Stokes laser pulses. Using the optical Bloch-Feynman equations, we

  5. Evolution of the Raman spectra from single-, few-, and many-layer graphene with increasing disorder

    SciTech Connect (OSTI)

    Martins Ferreira, E. H.; Stavale, F. [Divisao de Metrologia de Materiais, Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (INMETRO), Duque de Caxias 25250-020, RJ (Brazil); Moutinho, Marcus V. O. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cx. Postal 68528, Rio de Janeiro 21941-972, RJ (Brazil); Lucchese, M. M. [Divisao de Metrologia de Materiais, Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (INMETRO), Duque de Caxias 25250-020, RJ (Brazil); Centro de Ciencias Exatas e Tecnologicas, Universidade Federal do Pampa, Bage, Rio Grande do Sul (Brazil); Capaz, Rodrigo B. [Divisao de Metrologia de Materiais, Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (INMETRO), Duque de Caxias 25250-020, RJ (Brazil); Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cx. Postal 68528, Rio de Janeiro 21941-972, RJ (Brazil); Achete, C. A. [Divisao de Metrologia de Materiais, Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (INMETRO), Duque de Caxias 25250-020, RJ (Brazil); Programa de Engenharia Metalurgica e de Materiais (PEMM), Universidade Federal do Rio de Janeiro, Cx. Postal 68505, Rio de Janeiro 21945-970, RJ (Brazil); Jorio, A. [Divisao de Metrologia de Materiais, Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (INMETRO), Duque de Caxias 25250-020, RJ (Brazil); Depto. de Fisica, Universidade Federal de Minas Gerais, Belo Horizonte 30123-970, MG (Brazil)

    2010-09-15T23:59:59.000Z

    We report on the micro-Raman spectroscopy of monolayer, bilayer, trilayer, and many layers of graphene (graphite) bombarded by low-energy argon ions with different doses. The evolution of peak frequencies, intensities, linewidths, and areas of the main Raman bands of graphene is analyzed as function of the distance between defects and number of layers. We describe the disorder-induced frequency shifts and the increase in the linewidth of the Raman bands by means of a spatial-correlation model. Also, the evolution of the relative areas A{sub D}/A{sub G}, A{sub D}{sup '}/A{sub G}, and A{sub G}{sup '}/A{sub G} is described by a phenomenological model. The present results can be used to fully characterize disorder in graphene systems.

  6. Raman Spectroscopy of Lithium Hydride Corrosion: Selection of an Appropriate Excitation Wavelength to Minimize Fluorescence

    SciTech Connect (OSTI)

    Stowe, A. C.; Smyrl, N. R.

    2011-05-26T23:59:59.000Z

    The recent interest in a hydrogen-based fuel economy has renewed research into metal hydride chemistry. Many of these compounds react readily with water to release hydrogen gas and form a caustic. Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFT) has been used to study the hydrolysis reaction. The LiOH stretch appears at 3670 cm{sup -1}. Raman spectroscopy is a complementary technique that employs monochromatic excitation (laser) allowing access to the low energy region of the vibrational spectrum (<600 cm{sup -1}). Weak scattering and fluorescence typically prevent Raman from being used for many compounds. The role of Li{sub 2}O in the moisture reaction has not been fully studied for LiH. Li{sub 2}O can be observed by Raman while being hidden in the Infrared spectrum.

  7. Synthesis of few layer graphene by direct exfoliation of graphite and a Raman spectroscopic study

    SciTech Connect (OSTI)

    Gayathri, S.; Jayabal, P.; Ramakrishnan, V., E-mail: vr.optics1@gmail.com [Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai-625021, India. (India); Kottaisamy, M. [Department of Chemistry, Thiagarajar College of Engineering, Madurai-625015, India. (India)] [Department of Chemistry, Thiagarajar College of Engineering, Madurai-625015, India. (India)

    2014-02-15T23:59:59.000Z

    The exfoliation of graphene from pristine graphite in a liquid phase was achieved successfully via sonication followed by centrifugation method. Ultraviolet–visible (UV–vis) spectra of the obtained graphene dispersions at different exfoliation time indicated that the concentration of graphene dispersion increased markedly with increasing exfoliation time. The sheet-like morphology of the exfoliated graphene was revealed by Scanning Electron Microscopy (SEM) image. Further, the morphological change in different exfoliation time was investigated by Atomic Force Microscopy (AFM). A complete structural and defect characterization was probed using micro-Raman spectroscopic technique. The shape and position of the 2D band of Raman spectra revealed the formation of bilayer to few layer graphene. Also, Raman mapping confirmed the presence of uniformly distributed bilayer graphene sheets on the substrate.

  8. Relation between squeezing of vacuum fluctuations, quantum entanglement and sub-shot noise in Raman scattering

    E-Print Network [OSTI]

    Anirban Pathak; Jaromir Krepelka; Jan Perina

    2012-10-14T23:59:59.000Z

    A completely quantum description of Raman process is used to investigate the nonclassical properties of the modes in the stimulated, spontaneous and partially spontaneous Raman process. Both coherent scattering (where all the initial modes are coherent) and chaotic scattering (where initial phonon mode is chaotic and all the other modes are coherent) are studied. Nonclassical character of Raman process is observed by means of intermodal entanglement, single mode and intermodal squeezing of vacuum fluctuations, sub-shot noise and wave variances. Joint photon-phonon number and integrated-intensity distributions are then used to illustrate the observed nonclassicalities. Conditional and difference number distributions are also provided to illustrate the nonclassical character. The mutual relation between the obtained nonclassicalities and their variations dependent on phases, rescalled time and ratio of coupling constants are also reported.

  9. Raman spectra of R{sub 2}O{sub 3} (R—rare earth) sesquioxides with C-type bixbyite crystal structure: A comparative study

    SciTech Connect (OSTI)

    Abrashev, M. V., E-mail: mvabr@phys.uni-sofia.bg [Instituto de Física, UFRGS, Porto Alegre, 91501-970 Rio Grande do Sul (Brazil); Faculty of Physics, University of Sofia, BG-1164 Sofia (Bulgaria); Todorov, N. D. [Faculty of Physics, University of Sofia, BG-1164 Sofia (Bulgaria); Geshev, J. [Instituto de Física, UFRGS, Porto Alegre, 91501-970 Rio Grande do Sul (Brazil)

    2014-09-14T23:59:59.000Z

    Raman spectra of R{sub 2}O{sub 3} (R—Sc, Er, Y, Ho, Gd, Eu, and Sm) powders with C-type bixbyite crystal structure are measured. With the help of these data and ones, previously published for other oxides from the same structural family, general dependencies of the frequencies of the Raman peaks on the cubic crystal unit cell parameter are constructed. Using these dependencies and knowing the symmetry of the peaks for one of the oxides, determined from previous single-crystal measurements, it is possible to find out the symmetry of the peaks from the spectra of all compounds. It was found that the frequency of the six lowest frequency peaks scales with the square root of the mass of the rare earth showing that mainly R ions take part in these vibrations. These results agree with performed here lattice dynamical calculations. The anomalous softening of the frequency of some peaks in the spectra of Eu{sub 2}O{sub 3} is discussed.

  10. 382 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 22, NO. 2, FEBRUARY 2004 Effect of a Raman Co-Pump's RIN on the BER

    E-Print Network [OSTI]

    Lakoba, Taras I.

    382 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 22, NO. 2, FEBRUARY 2004 Effect of a Raman Co-Pump's RIN from a Raman co-pump, on the bit-error rate (BER). We show that a given amount of the transferred RIN spontaneous emission (ASE) noise, than erbium amplifiers. The backward-pumping scheme, where the Raman pump

  11. Raman Scattering from 1,3-Propanedithiol at a Hot Spot: Theory Meets Experiment

    SciTech Connect (OSTI)

    El-Khoury, Patrick Z.; Hess, Wayne P.

    2013-08-21T23:59:59.000Z

    We compute the Raman spectra of 1,3-propanedithiol (PDT) in the gas phase, in methanol, linked either to the face or vertex of a finite tetrahedral Ag20 cluster, and linking two Ag20 clusters using tools of density functional theory. The calculated normal mode-dependent molecular polarizability derivative tensors are employed to simulate single molecule surface-enhanced Raman (SERS) spectra. This is achieved by rotating the polarizability tensors of an individual molecule with respect to explicitly defined vector components of the incident and scattered radiation. Our results provide a basis for understanding commonly observed phenomena in single molecule SERS spectroscopy.

  12. Cooling in reduced period optical lattices: non-zero Raman detuning

    E-Print Network [OSTI]

    V. S. Malinovsky; P. R. Berman

    2006-05-06T23:59:59.000Z

    In a previous paper [Phys. Rev. A 72, 033415 (2005)], it was shown that sub-Doppler cooling occurs in a standing-wave Raman scheme (SWRS) that can lead to reduced period optical lattices. These calculations are extended to allow for non-zero detuning of the Raman transitions. New physical phenomena are encountered, including cooling to non-zero velocities, combinations of Sisyphus and "corkscrew" polarization cooling, and somewhat unusual origins of the friction force. The calculations are carried out in a semi-classical approximation and a dressed state picture is introduced to aid in the interpretation of the results.

  13. Coherent anti-Stokes Raman microspectroscopy using spectral focusing with glass dispersion

    SciTech Connect (OSTI)

    Rocha-Mendoza, Israel; Langbein, Wolfgang; Borri, Paola [School of Biosciences and School of Physics and Astronomy, Cardiff University, Museum Avenue, Cardiff CF10 3US (United Kingdom)

    2008-11-17T23:59:59.000Z

    We demonstrate experimentally that coherent anti-Stokes Raman microspectroscopy with high spectral resolution is achieved using femtosecond laser pulses chirped up to a few picoseconds by glass elements of known group-velocity dispersion without significant intensity losses. By simply choosing the length of the glass, the chirp of Stokes and pump pulses is tailored to obtain a spectral resolution given by the Fourier limit of the chirped pulse duration. We show that for chirped pulse durations shorter than or comparable to the Raman coherence time, maximum signal occurs for a pump arriving after the Stokes pulse, a time-ordering effect confirmed by numerical simulations.

  14. Enhancement of photoluminescence and raman scattering in one-dimensional photonic crystals based on porous silicon

    SciTech Connect (OSTI)

    Gonchar, K. A., E-mail: k.a.gonchar@gmail.com [Moscow State University, Physics Faculty (Russian Federation); Musabek, G. K.; Taurbayev, T. I. [Al Farabi Kazakh National University, Physics Department (Kazakhstan); Timoshenko, V. Yu. [Moscow State University, Physics Faculty (Russian Federation)

    2011-05-15T23:59:59.000Z

    In porous-silicon-based multilayered structures that exhibit the properties of one-dimensional photonic crystals, an increase in the photoluminescence and Raman scattering intensities is observed upon optical excitation at the wavelength 1.064 {mu}m. When the excitation wavelength falls within the edge of the photonic band gap of the structures, a multiple increase (by a factor larger than 400) in the efficiency of Raman scattering is detected. The effect is attributed to partial localization of excitation light and, correspondingly, to the much longer time of interaction of light with the material in the structures.

  15. Fourier Transform Raman Spectroscopy of Photoactive Proteins with Near-Infrared Excitation

    E-Print Network [OSTI]

    Johnson, Carey K.; Rubinovitz, Ronald

    1990-07-01T23:59:59.000Z

    -adapted by light from a 14-W tungsten bulb for 45 min before being transferred to a cuvette for Raman analysis. Photosynthetic reaction centers of Rhodobacter sphaeroides were generously donated by Prof. Robert Blankenship (Arizona State University). The sample... carbonyl vibrations of BChl and BPh. In contrast o bR, there is no clear and consistent correspondence in Fig. 2B with the rel- ative intensities of Qx, Qy, or Soret-enhanced resonance Raman spectra of RCs, perhaps because of the existence of several...

  16. Demonstration of triple pump coherent anti-Stokes Raman scattering in a jet diffusion flame

    E-Print Network [OSTI]

    Velur Natarajan, Viswanathan

    2002-01-01T23:59:59.000Z

    using the principle. The Sandia CARSFT code [l0] was used to determine temperature and species con- centration from the two dual-puinp CARS spectra using spectral fits. The CARSFT code was modified for dual-pump CARS calculations. It is assumed thai.... This process enables the detection of two species whose Raman shifts are significantly different; this is the advantage of this technique over two-laser CARS. The Sandia CARSFT code was modified so that the Raman shift of one species is a free parameter...

  17. Raman Spectroscopy of UH3 from the Hydrogen Corrosion of Uranium

    SciTech Connect (OSTI)

    Smyrl, N. R.; Stowe, A. C.; Powell, G. L.

    2011-05-31T23:59:59.000Z

    Hydrogen reacts with a uranium surface to form a fine, pyrophoric metal power (UH{sub 3}). Few spectroscopic studies have been conducted to study this reaction. Advances in Raman spectroscopy permit the application of the Raman method to formally difficult areas of chemistry such as the hydrogen corrosion of uranium: availability of multiple laser excitation wavelengths; fiber optics delivery and collection systems; upgraded instrumentation and detection techniques; and development of special enclosed in situ reactor cells. UH{sub 3} vibrations are expected to occur at low frequencies due to extended U-H-U structure.

  18. Role of noise operators on two-photon correlations in an extended coherent Raman medium

    E-Print Network [OSTI]

    Ooi, C. H. Raymond; Zubairy, M. Suhail.

    2007-01-01T23:59:59.000Z

    Role of noise operators on two-photon correlations in an extended coherent Raman medium C. H. Raymond Ooi1,2,3,4,* and M. Suhail Zubairy3,5 1Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 305-701 Korea 2Max... & Aerospace Engineering, Princeton University, New Jersey 08544, USA 5Texas A&M University at Qatar, Education City, P.O. Box 23874, Doha, Qatar #1;Received 8 January 2007; published 29 May 2007#2; An extended medium driven in a double Raman configuration...

  19. Structural dynamics of phenylisothiocyanate in the light-absorbing excited states: Resonance Raman and complete active space self-consistent field calculation study

    SciTech Connect (OSTI)

    Ouyang, Bing, E-mail: ouyangbing.zj@foxmail.com; Xue, Jia-Dan, E-mail: jenniexue@126.com; Zheng, Xuming, E-mail: zhengxuming126@126.com, E-mail: zxm@zstu.edu.cn, E-mail: fangwh@dnu.edu.cn [Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018 (China)] [Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Fang, Wei-Hai, E-mail: zxm@zstu.edu.cn, E-mail: fangwh@dnu.edu.cn, E-mail: fangwh@dnu.edu.cn [Department of Chemistry, Beijing Normal University, Beijing 100875 (China)] [Department of Chemistry, Beijing Normal University, Beijing 100875 (China)

    2014-05-21T23:59:59.000Z

    The excited state structural dynamics of phenyl isothiocyanate (PITC) after excitation to the light absorbing S{sub 2}(A?), S{sub 6}(A?), and S{sub 7}(A?) excited states were studied by using the resonance Raman spectroscopy and complete active space self-consistent field method calculations. The UV absorption bands of PITC were assigned. The vibrational assignments were done on the basis of the Fourier transform (FT)-Raman and FT-infrared measurements, the density-functional theory computations, and the normal mode analysis. The A-, B-, and C-bands resonance Raman spectra in cyclohexane, acetonitrile, and methanol solvents were, respectively, obtained at 299.1, 282.4, 266.0, 252.7, 228.7, 217.8, and 208.8 nm excitation wavelengths to probe the corresponding structural dynamics of PITC. The results indicated that the structural dynamics in the S{sub 2}(A?), S{sub 6}(A?), and S{sub 7}(A?) excited states were very different. The conical intersection point CI(S{sub 2}/S{sub 1}) were predicted to play important role in the low-lying excited state decay dynamics. Two major decay channels were predicted for PITC upon excitation to the S{sub 2}(A?) state: the radiative S{sub 2,min} ? S{sub 0} transition and the nonradiative S{sub 2} ? S{sub 1} internal conversion via CI(S{sub 2}/S{sub 1}). The differences in the decay dynamics between methyl isothiocyanate and PITC in the first light absorbing excited state were discussed. The role of the intersystem crossing point ISC(S{sub 1}/T{sub 1}) in the excited state decay dynamics of PITC is evaluated.

  20. A precise narrow-beam filter infrared radiometer and its use with lidar in the ARM Program

    SciTech Connect (OSTI)

    Platt, C.M.R.

    1992-05-01T23:59:59.000Z

    The first six months of the grant (December 1991--May 1992) have been taken up with the design and specification for the new narrow-beam radiometer. The radiometer will be built and tested at the Division of Atmospheric Research over the next three months. Improved algorithms for obtaining cloud extinction have also been developed. It is proposed during 1993 to use the radiometer in conjunction with a new CSIRO 3-wavelength lidar in the ARM PROBE experiment at Kavieng, New Guinea, which is a test mission under tropical conditions for the ARM CART Tropical West Pacific site, and is part of the TOGA COARE experiment. During the latter part of 1992, the radiometer will be tested thoroughly and tested at the Division of Atmospheric Research, Aspendale.

  1. JOURNAL DE PHYSIQUE Colloque CS,suppltfmentau n" 6, Tome 41, juin 1980,page ~ 5 -2 4 1 SPIN-DEPENDENT RAMAN SCATTERING FROM PHONONS I N MAGNETIC SEMICONDUCTORS AND INSULATORS

    E-Print Network [OSTI]

    Boyer, Edmond

    -DEPENDENT RAMAN SCATTERING FROM PHONONS I N MAGNETIC SEMICONDUCTORS AND INSULATORS + ++G. Giintherodt, R. Merlin

  2. Developments in enzyme immobilization and near-infrared Raman spectroscopy with downstream renewable energy applications

    SciTech Connect (OSTI)

    Lupoi, Jason [Ames Laboratory

    2012-08-27T23:59:59.000Z

    This dissertation focuses on techniques for (1) increasing ethanol yields from saccharification and fermentation of cellulose using immobilized cellulase, and (2) the characterization and classification of lignocellulosic feedstocks, and quantification of useful parameters such as the syringyl/guaiacyl (S/G) lignin monomer content using 1064 nm dispersive multichannel Raman spectroscopy and chemometrics.

  3. Performance Enhancement of Raman-based Distributed Temperature Sensors using Simplex Codes

    E-Print Network [OSTI]

    Park, Namkyoo

    Performance Enhancement of Raman-based Distributed Temperature Sensors using Simplex Codes G, Seoul National University, Korea. E-mail: nkpark@plaza.snu.ac.kr Abstract: Using 63 bit simplex coding]. The use of simplex coding (S-coding) in conjunction with OTDR can be effectively used to enhance

  4. Atomic force microscope with combined FTIR-Raman spectroscopy having a micro thermal analyzer

    SciTech Connect (OSTI)

    Fink, Samuel D. (Aiken, SC); Fondeur, Fernando F. (North Augusta, SC)

    2011-10-18T23:59:59.000Z

    An atomic force microscope is provided that includes a micro thermal analyzer with a tip. The micro thermal analyzer is configured for obtaining topographical data from a sample. A raman spectrometer is included and is configured for use in obtaining chemical data from the sample.

  5. Layers for Effective Volume Rendering Sundaresan Raman, Oleg Mishchenko, and Roger Crawfis, Member, IEEE Computer Society

    E-Print Network [OSTI]

    Crawfis, Roger

    Layers for Effective Volume Rendering Sundaresan Raman, Oleg Mishchenko, and Roger Crawfis, Member, IEEE Computer Society Abstract--A multi-layer volume rendering framework is presented. The final image is obtained by compositing a number of renderings, each being represented as a separate layer. This layer

  6. Improving total column ozone retrievals by using cloud pressures derived from Raman scattering in the UV

    E-Print Network [OSTI]

    Joiner, Joanna

    Improving total column ozone retrievals by using cloud pressures derived from Raman scattering resolution, coverage, and sampling of the Aura satellite ozone monitoring instrument (OMI), as compared with the total ozone mapping spectrometer (TOMS) should allow for improved ozone retrievals. By default, the TOMS

  7. Effect of a magnetic field on the two-phonon Raman scattering in C. Faugeras,1

    E-Print Network [OSTI]

    Boyer, Edmond

    Effect of a magnetic field on the two-phonon Raman scattering in graphene C. Faugeras,1 P. Kossacki spectrum of graphene (the two-phonon peak near 2700 cm-1) in an external magnetic field applied perpendicular to the graphene crystal plane at liquid helium temperature. A shift to lower frequency

  8. Observation of spontaneous Raman scattering in silicon slow-light photonic crystal waveguides

    E-Print Network [OSTI]

    Hone, James

    in silicon rib waveguides1 through the observations of amplification2 and finally to lasing.3,4 In addition to these achievements in rela- tively large mode area rib waveguides, the observation of spontaneous scattering5 and amplification6 has been made in submicron channel waveguides. In order to reduce the threshold power of Raman

  9. BARANIDHARAN (BARANI) RAMAN, B.Eng., M.S., Ph.D. Brauer Hall, 2007

    E-Print Network [OSTI]

    Raman, Barani

    , and M. Stopfer, "Temporally diverse firing patterns in olfactory receptor neurons underlie spatio microsensors," IEEE Sensors, Special Issue on Sensors for Breath Analysis, Vol. 10, pp. 137-144, January 2010. Raman, and M. Stopfer, "Frequency transitions in odor- evoked neural oscillations," Neuron, Vol. 64, pp

  10. Raman and conductivity studies of boron doped microcrystalline diamond, facetted nanocrystalline diamond

    E-Print Network [OSTI]

    Bristol, University of

    superconductivity at temperatures polycrystalline boron-doped CVD diamond filmsRaman and conductivity studies of boron doped microcrystalline diamond, facetted nanocrystalline diamond and cauliflower diamond films P.W. May a,*, W.J. Ludlow a , M. Hannaway a , P.J. Heard b , J

  11. Raman and Photoluminescence Spectroscopy of Nanocrystalline Diamond Films grown by Hot Filament CVD

    E-Print Network [OSTI]

    Bristol, University of

    H4 flow-rate ratio of standard polycrystalline diamond deposition parameters on formationRaman and Photoluminescence Spectroscopy of Nanocrystalline Diamond Films grown by Hot Filament CVD of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia b,c Diamond Research Laboratory, School

  12. RGLES DE SLECTION POUR LA DIFFUSION RAMAN ET L'ABSORPTION INFRAROUGE DANS LA WURTZITE (1)

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    689. R�GLES DE S�LECTION POUR LA DIFFUSION RAMAN ET L'ABSORPTION INFRAROUGE DANS LA WURTZITE (1 du groupe de symétrie de la wurtzite aux points 0393, A, M, K de la zone de Brillouin ont été. Abstract. - The irreducible representations of the wurtzite space group corresponding to the 0393, A, M

  13. Demonstration of a Mid-infrared silicon Raman Varun Raghunathan1

    E-Print Network [OSTI]

    Jalali. Bahram

    . 13, 3396-3408 (2007). 16. A. Yariv, Quantum Electronics, 3rd ed., John Wiley and Sons, New York (1988 Raman laser," Opt. Express. 12, 5269-5273 (2004). 2. H. Rong, R. Jones, A. Liu, O. Cohen, D. Hak, A, Baltimore, MD, May 2005, CMU1. 4. A. Liu, H. Rong, M. Paniccia, O. Cohen, and D. Hak, "Net optical gain

  14. X-ray amplification from a Raman Free Electron Laser I.A. Andriyash,

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    X-ray amplification from a Raman Free Electron Laser I.A. Andriyash, E. d'Humi`eres, V 5107, F33400 Talence, France We demonstrate that a mm-scale free electron laser can operate in the X and health applications. Large scale X-ray free electron laser (XFEL) projects have been launched, and start

  15. Structure in Nascent Carbon Nanotubes Revealed by Spatially Resolved Raman Spectroscopy

    E-Print Network [OSTI]

    or filtration [1], supercapacitors [2], composite materials [3,4]. They are mainly prepared by CVD (Chemical1 Structure in Nascent Carbon Nanotubes Revealed by Spatially Resolved Raman Spectroscopy Périne: The understanding of carbon nanotubes (CNT) growth is crucial for the control of their production. In particular

  16. Raman spectroscopy on surfacted ferrofluids in a magnetic field J. E. Weber,1

    E-Print Network [OSTI]

    Nabben, Reinhard

    a magnetic excitation with an intensity growing in proportion to the magnetization of the ferrofluid becomes of counteracting in- teractions. On one hand, thermal motion and electrostatic or surfactant-mediated repulsion scatter- ing in general and Raman spectroscopy in particular are a very powerful and sensitive tool

  17. Raman spectra of out-of-plane phonons in bilayer graphene

    E-Print Network [OSTI]

    Sato, Kentaro

    The double resonance Raman spectra of the overtone of the out-of-plane tangential optical (oTO) phonon and of combinations of the LO, ZO, and ZA phonons with one another are calculated for bilayer graphene. In the case of ...

  18. hal-00276997,version1-5May2008 Raman spectra of misoriented bilayer graphene

    E-Print Network [OSTI]

    hal-00276997,version1-5May2008 Raman spectra of misoriented bilayer graphene P. Poncharal1 , A layer graphene with a bilayer in which the two layers are arbitrarily misoriented. The profiles of the 2 of the electronic structures of single layer graphene and misoriented bilayer graphene. Another new aspect

  19. Development of the Mars microbeam Raman spectrometer (MMRS) Alian Wang,1

    E-Print Network [OSTI]

    mineralogy in a planetary exploration. INDEX TERMS: 3672 Mineralogy and Petrology: Planetary mineralogy and petrology (5410); 3694 Mineralogy and Petrology: Instruments and techniques; 3994 Mineral Physics: Raman spectroscopy, Mars in-situ mineralogy, Planetary on-surface mineral identification, Water on Mars

  20. INDIAN ACADEMY OF SCIENCES C.V.RamanAvenue,Sadashivanagar,Bangalore560080.

    E-Print Network [OSTI]

    Joshi, Yogesh Moreshwar

    INDIAN ACADEMY OF SCIENCES C.V.RamanAvenue,Sadashivanagar,Bangalore560080. Indian Academy of the Academy consist of publication of scientific journals, election of Fellows, organizing scientific meetings, initiatives such as promoting science education,etc. The Academy is looking for a suitable person to fill

  1. Indian Academy of Sciences C V Raman Avenue, Sadashivanagar, Bangalore 560 080

    E-Print Network [OSTI]

    Joshi, Yogesh Moreshwar

    Indian Academy of Sciences C V Raman Avenue, Sadashivanagar, Bangalore 560 080 No. : IASc/ /13 System' The Indian Academy of Sciences is in need of `Multi-point Video Conference System: The Purchase In-charge, Indian Academy of Sciences latest by 30th December 2013 by 15:00 PM. Technical

  2. Micro-resonance Raman study of optically trapped Escherichia coli cells overexpressing human neuroglobin

    E-Print Network [OSTI]

    Wenseleers, Wim

    neuroglobin Kerstin Ramser Göteborgs University Department of Physics SE-412 96 Göteborg, Sweden and Luleå coli E. coli overexpressing wild type wt neuroglobin NGB and its E7Leu mutant, respectively. NGB. DOI: 10.1117/1.2753478 Keywords: E. coli bacteria; neuroglobin; E7Leu neuroglobin; resonance Raman

  3. Hydrostatic pressure dependence of the luminescence and Raman frequencies in polyfluorene C. M. Martin,1

    E-Print Network [OSTI]

    Chandrasekhar, Meera

    , absorption, and Raman scattering spectra from poly 2,7-,,9,9 -bis(2-ethylhexyl)...fluorene under hydrostatic fabricated from the PF family of materials are known to degrade under operation. The desired blue elec,14 In this work we probe the optical properties of poly 2,7-,,9,9 -bis(2-ethylhexyl)...fluorene PF2/6 via PL

  4. MESOSCALE ANALYSIS OF A CAROLINA COASTAL FRONT SETHU RAMAN, NEERAJA C. REDDY and DEVDUTTA S. NIYOGI

    E-Print Network [OSTI]

    Niyogi, Dev

    MESOSCALE ANALYSIS OF A CAROLINA COASTAL FRONT SETHU RAMAN, NEERAJA C. REDDY and DEVDUTTA S. NIYOGI the shore. Key words: GALE, Coastal front, Atmospheric boundary layer, Gulf Stream, Mesoscale analysis turbulent heat fluxes. These strong gradients in heat fluxes enhance mesoscale circulation

  5. THE JOURNAL OF CHEMICAL PHYSICS 139, 124113 (2013) Time-resolved broadband Raman spectroscopies: A unified

    E-Print Network [OSTI]

    Mukamel, Shaul

    2013-01-01T23:59:59.000Z

    be defined as a change of the energy of the electromagnetic field S = - dt d dt a i (t)ai(t) = I 2 ¯ - dt and frequency resolved Raman techniques have been developed towards monitoring ex- cited and ground state the system with pulse Ej and deex- cites it with E i . We use complex pulse amplitudes. The elec- tronically

  6. In situ Raman spectroscopic studies of trimethylindium pyrolysis in an OMVPE reactor

    E-Print Network [OSTI]

    Anderson, Timothy J.

    In situ Raman spectroscopic studies of trimethylindium pyrolysis in an OMVPE reactor Chinho Park decomposition reactions of trimethylindium (TMIn) in a vertical, upflow chemical vapor deposition reactor has along the vertical centerline of the reactor. Introduction Organometallic vapor phase epitaxy (OMVPE

  7. Effect of functionalization on the electrostatic charging, tunneling, and Raman spectroscopy of epitaxial graphene

    E-Print Network [OSTI]

    of epitaxial graphene Jeongmin Hong, Sandip Niyogi, Elena Bekyarova, Mikhail E. Itkis, Palanisamy Ramesh graphene Appl. Phys. Lett. 101, 111602 (2012); 10.1063/1.4752443 Evidences of electrochemical graphene (2012); 10.1063/1.4725489 Pinned and unpinned epitaxial graphene layers on SiC studied by Raman

  8. Spatially resolved photoluminescence and Raman scattering experiments on the GaN/substrate interface

    E-Print Network [OSTI]

    Nabben, Reinhard

    Spatially resolved photoluminescence and Raman scattering experiments on the GaN experiments on the substrate interface region of wurtzite GaN layers. We show that the broad photoluminescence band with an intensity maximum at 2.4 eV is not an intrinsic property of GaN. We found

  9. Feedback control of ultra-high-Q microcavities: application to micro-Raman lasers and micro-

    E-Print Network [OSTI]

    Feedback control of ultra-high-Q microcavities: application to micro-Raman lasers and micro-cavity to a pump laser using two, distinct methods: coupled power stabilization and wavelength locking of pump laser to the microcavity. In addition to improvements in operation of previously demonstrated micro

  10. Thermal metamorphism in the lesser Himalaya of Nepal determined from Raman spectroscopy of carbonaceous material

    E-Print Network [OSTI]

    Avouac, Jean-Philippe

    Thermal metamorphism in the lesser Himalaya of Nepal determined from Raman spectroscopy of central and far-western Nepal, including data from near the MCT zone, where a comparison with conventional on the thermal evolution of the Himalaya in Nepal using the RSCM method. This emblematic geological setting

  11. Raman and absorption spectrophotometric studies of selected lanthanide, californium-doped lanthanide, and actinide trihalides in the solid state

    SciTech Connect (OSTI)

    Wilmarth, W.R.

    1988-03-01T23:59:59.000Z

    The solid-state absorption spectra of Cf(III) ions as a dopant in lanthanide trihalide hosts (LnCl/sub 3/: Ln = Ce, Sm, and Y; LnBr/sub 3/: Ln = Ce, Sm, Tb, and Y; LnI/sub 3/: Ln = Ce and Y) have been recorded. The spectra of Cf(III) have been correlated with the various crystal structures. The phonon Raman spectra and solid-state absorption spectra of PmF/sub 3/, PmCl/sub 3/, PmBr/sub 3/, and two crystal modifications of PmI/sub 3/ have been recorded. Symmetry assignments have been made for the Raman-active bands for these trihalides and also the sesquioxide. The room-temperature absorption spectra have been correlated to crystal field effects. The symmetry assignments of the Raman-active phonon modes have been made based on polarized Raman spectra from single crystals of YF/sub 3/-type orthorhombic TbF/sub 3/ and PuBr/sub 3/-type orthorhombic NdBr/sub 3/. Raman spectra of other isostructural lanthanide compounds have been recorded and compared. Symmetry assignments for these compounds have been made by analogy to the single-crystal assignments. Raman spectra have been obtained and catalogued for a number of actinide compounds. Symmetry assignments have been made for the observed Raman-active phonon bands in this work based on the assignments made for isostructural lanthanide compounds. 29 figs., 22 tabs.

  12. Object-Based Image Analysis of Downed Logs in Disturbed Forested Landscapes Using Lidar

    E-Print Network [OSTI]

    Kelly, Maggi

    2011-01-01T23:59:59.000Z

    quantity and location of downed logs in forests is important for assessing fire risk [4,5], measuring dead biomass

  13. Phonon renormalization and Raman spectral evolution through amorphous to crystalline transitions in Sb{sub 2}Te{sub 3} thin films

    SciTech Connect (OSTI)

    Secor, Jeff; Zhao, Lukas; Krusin-Elbaum, Lia [The Graduate Center, CUNY, New York, New York 10016 (United States); Department of Physics, The City College of New York, CUNY, New York, New York 10031 (United States); Harris, Matt A.; Deng, Haiming [Department of Physics, The City College of New York, CUNY, New York, New York 10031 (United States); Raoux, Simone [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

    2014-06-02T23:59:59.000Z

    A symmetry specific phonon mode renormalization is observed across an amorphous to crystalline phase transformation in thin films of the topological material Sb{sub 2}Te{sub 3} using Raman spectroscopy. We present evidence for local crystalline symmetry in the amorphous state, eventhough, the q?=?0 Raman selection rule is broken due to strong structural disorder. At crystallization, the in-plane polarized (E{sub g}{sup 2}) mode abruptly sharpens while the out-of-plane polarized (A{sub 1g}) modes are only weakly effected. This effect unique to the E{sub g} symmetry is exceptional considering that polarized spectra and comparison of the single phonon density of states between the amorphous and crystalline phases suggest that short range order of the amorphous phase is, on the average, similar to that of the crystalline material while electrical transport measurements reveal a sharp insulator-to-metal transition. Our findings point to the important role of anisotropic disorder affecting potential applications of topological and phase-change based electronics.

  14. Multidimensional resonance raman spectroscopy by six-wave mixing in the deep UV

    SciTech Connect (OSTI)

    Molesky, Brian P.; Giokas, Paul G.; Guo, Zhenkun; Moran, Andrew M., E-mail: ammoran@email.unc.edu [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States)

    2014-09-21T23:59:59.000Z

    Two-dimensional (2D) resonance Raman spectroscopies hold great potential for uncovering photoinduced relaxation processes in molecules but are not yet widely applied because of technical challenges. Here, we describe a newly developed 2D resonance Raman experiment operational at the third-harmonic of a Titanium-Sapphire laser. High-sensitivity and rapid data acquisition are achieved by combining spectral interferometry with a background-free (six-pulse) laser beam geometry. The third-harmonic laser pulses are generated in a filament produced by the fundamental and second-harmonic pulses in neon gas at pressures up to 35 atm. The capabilities of the setup are demonstrated by probing ground-state wavepacket motions in triiodide. The information provided by the experiment is explored with two different representations of the signal. In one representation, Fourier transforms are carried out with respect to the two experimentally controlled delay times to obtain a 2D Raman spectrum. Further insights are derived in a second representation by dispersing the signal pulse in a spectrometer. It is shown that, as in traditional pump-probe experiments, the six-wave mixing signal spectrum encodes the wavepacket's position by way of the (time-evolving) emission frequency. Anharmonicity additionally induces dynamics in the vibrational resonance frequency. In all cases, the experimental signals are compared to model calculations based on a cumulant expansion approach. This study suggests that multi-dimensional resonance Raman spectroscopies conducted on systems with Franck-Condon active modes are fairly immune to many of the technical issues that challenge off-resonant 2D Raman spectroscopies (e.g., third-order cascades) and photon-echo experiments in the deep UV (e.g., coherence spikes). The development of higher-order nonlinear spectroscopies operational in the deep UV is motivated by studies of biological systems and elementary organic photochemistries.

  15. Measurement of Aerosols at the Pierre Auger Observatory

    E-Print Network [OSTI]

    S. Y. BenZvi; F. Arqueros; R. Cester; M. Chiosso; B. M. Connolly; B. Fick; A. Filipcic; B. García; A. Grillo; F. Guarino; M. Horvat; M. Iarlori; C. Macolino; M. Malek; J. Matthews; J. A. J. Matthews; D. Melo; R. Meyhandan; M. Micheletti; M. Monasor; M. Mostafá; R. Mussa; J. Pallotta; S. Petrera; M. Prouza; V. Rizi; M. Roberts; J. R. Rodriguez Rojo; D. Rodríguez-Frías; F. Salamida; M. Santander; G. Sequeiros; P. Sommers; A. Tonachini; L. Valore; D. Verberic; E. Visbal; S. Westerhoff; L. Wiencke; D. Zavrtanik; M. Zavrtanik; for the Pierre Auger Collaboration

    2007-06-21T23:59:59.000Z

    The air fluorescence detectors (FDs) of the Pierre Auger Observatory are vital for the determination of the air shower energy scale. To compensate for variations in atmospheric conditions that affect the energy measurement, the Observatory operates an array of monitoring instruments to record hourly atmospheric conditions across the detector site, an area exceeding 3,000 square km. This paper presents results from four instruments used to characterize the aerosol component of the atmosphere: the Central Laser Facility (CLF), which provides the FDs with calibrated laser shots; the scanning backscatter lidars, which operate at three FD sites; the Aerosol Phase Function monitors (APFs), which measure the aerosol scattering cross section at two FD locations; and the Horizontal Attenuation Monitor (HAM), which measures the wavelength dependence of aerosol attenuation.

  16. Wide-angle imaging LIDAR (WAIL): a ground-based instrument for monitoring the thickness and density of optically thick clouds.

    SciTech Connect (OSTI)

    Love, Steven P.; Davis, A. B. (Anthony B.); Rohde, C. A. (Charles A.); Ho, Cheng,

    2001-01-01T23:59:59.000Z

    Traditional lidar provides little information on dense clouds beyond the range to their base (ceilometry), due to their extreme opacity. At most optical wavelengths, however, laser photons are not absorbed but merely scattered out of the beam, and thus eventually escape the cloud via multiple scattering, producing distinctive extended space- and time-dependent patterns which are, in essence, the cloud's radiative Green functions. These Green functions, essentially 'movies' of the time evolution of the spatial distribution of escaping light, are the primary data products of a new type of lidar: Wide Angle Imaging Lidar (WAIL). WAIL data can be used to infer both optical depth and physical thickness of clouds, and hence the cloud liquid water content. The instrumental challenge is to accommodate a radiance field varying over many orders of magnitude and changing over widely varying time-scales. Our implementation uses a high-speed microchannel plate/crossed delay line imaging detector system with a 60-degree full-angle field of view, and a 532 nm doubled Nd:YAG laser. Nighttime field experiments testing various solutions to this problem show excellent agreement with diffusion theory, and retrievals yield plausible values for the optical and geometrical parameters of the observed cloud decks.

  17. Spectroscopic Monitoring of Spent Nuclear Fuel Reprocessing Streams: An Evaluation of Spent Fuel Solutions via Raman, Visible, and Near-Infrared Spectroscopy

    SciTech Connect (OSTI)

    Bryan, Samuel A.; Levitskaia, Tatiana G.; Johnsen, Amanda M.; Orton, Christopher R.; Peterson, James M.

    2011-09-01T23:59:59.000Z

    The potential of using optical spectroscopic techniques, such as Raman and Visible/Near Infrared (Vis/NIR), for on-line process control and special nuclear materials accountability applications at a spent nuclear fuel reprocessing facility was evaluated. Availability of on-line real-time techniques that directly measure process concentrations of nuclear materials will enhance performance and proliferation resistance of the solvent extraction processes. Further, on-line monitoring of radiochemical streams will also improve reprocessing plant operation and safety. This report reviews current state of development of the spectroscopic on-line monitoring techniques for such solutions. To further examine applicability of optical spectroscopy for monitoring reprocessing solutions, segments of a spent nuclear fuel, with approximate burn-up values of 70 MWd/kgM, were dissolved in concentrated nitric acid and adjusted to varying final concentrations of HNO3. The resulting spent fuel solutions were batch-contacted with tributyl phosphate/dodecane organic solvent. The feed and equilibrium aqueous and loaded organic solutions were subjected to optical measurements. The obtained spectra showed the presence of the quantifiable Raman bands due to NO3- and UO22+ and Vis/NIR bands due to multiple species of Pu(IV), Pu(VI), Np(V), the Np(V)-U(VI) cation-cation complex, and Nd(III) in fuel solutions, justifying spectroscopic techniques as a promising methodology for monitoring spent fuel processing solutions in real-time. Quantitative evaluation of the fuel solution was performed based on spectroscopic measurements and compared to ICP-MS analysis.

  18. Charge Density Waves in Exfoliated Films of van der Waals Materials: Evolution of Raman Spectrum in TiSe2

    E-Print Network [OSTI]

    Charge Density Waves in Exfoliated Films of van der Waals Materials: Evolution of Raman Spectrum graphene-like mechanical exfoliation of TiSe2 crystals to prepare a set of films with different thicknesses

  19. Remote Raman - laser induced breakdown spectroscopy (LIBS) geochemical investigation under Venus atmospheric conditions

    SciTech Connect (OSTI)

    Clegg, Sanuel M [Los Alamos National Laboratory; Barefield, James E [Los Alamos National Laboratory; Humphries, Seth D [Los Alamos National Laboratory; Wiens, Roger C [Los Alamos National Laboratory; Vaniman, D. T. [Los Alamos National Laboratory; Sharma, S. K. [UNIV OF HAWAII; Misra, A. K. [UNIV OF HAWAII; Dyar, M. D. [MT. HOLYOKE COLLEGE; Smrekar, S. E. [JET PROPULSION LAB.

    2010-12-13T23:59:59.000Z

    The extreme Venus surface temperatures ({approx}740 K) and atmospheric pressures ({approx}93 atm) create a challenging environment for surface missions. Scientific investigations capable of Venus geochemical observations must be completed within hours of landing before the lander will be overcome by the harsh atmosphere. A combined remote Raman - LIBS (Laser Induced Breakdown Spectroscopy) instrument is capable of accomplishing the geochemical science goals without the risks associated with collecting samples and bringing them into the lander. Wiens et al. and Sharma et al. demonstrated that both analytical techniques can be integrated into a single instrument capable of planetary missions. The focus of this paper is to explore the capability to probe geologic samples with Raman - LIBS and demonstrate quantitative analysis under Venus surface conditions. Raman and LIBS are highly complementary analytical techniques capable of detecting both the mineralogical and geochemical composition of Venus surface materials. These techniques have the potential to profoundly increase our knowledge of the Venus surface composition, which is currently limited to geochemical data from Soviet Venera and VEGA landers that collectively suggest a surface composition that is primarily tholeiitic basaltic with some potentially more evolved compositions and, in some locations, K-rich trachyandesite. These landers were not equipped to probe the surface mineralogy as can be accomplished with Raman spectroscopy. Based on the observed compositional differences and recognizing the imprecise nature of the existing data, 15 samples were chosen to constitute a Venus-analog suite for this study, including five basalts, two each of andesites, dacites, and sulfates, and single samples of a foidite, trachyandesite, rhyolite, and basaltic trachyandesite under Venus conditions. LIBS data reduction involved generating a partial least squares (PLS) model with a subset of the rock powder standards to quantitatively determine the major elemental abundance of the remaining samples. PLS analysis suggests that the major element compositions can be determined with root mean square errors ca. 5% (absolute) for SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}(total), MgO, and CaO, and ca. 2% or less for TiO{sub 2}, Cr{sub 2}O{sub 3}, MnO, K{sub 2}O, and Na{sub 2}O. Finally, the Raman experiments have been conducted under supercritical CO{sub 2} involving single-mineral and mixed-mineral samples containing talc, olivine, pyroxenes, feldspars, anhydrite, barite, and siderite. The Raman data have shown that the individual minerals can easily be identified individually or in mixtures.

  20. Stimulated Raman scattering of laser in a plasma in the presence of a co-propagating electron beam

    SciTech Connect (OSTI)

    Parashar, J. [Department of Physics, Samrat Ashok Technological Institute, Vidisha, Madhya Pradesh 464001 (India)] [Department of Physics, Samrat Ashok Technological Institute, Vidisha, Madhya Pradesh 464001 (India)

    2013-12-15T23:59:59.000Z

    A relativistic electron beam co-propagating with a high power laser in plasma is shown to add to the growth of the stimulated Raman back scattering of the laser. The growth rate is sensitive to phase matching of electron beam with the plasma wave. In the case of phase mismatch, the growth rate drops by an order. The energy spread of the electron beam significantly reduces the effectiveness of the beam on the stimulated Raman process.

  1. A New Methodology for Characterization of Environmentally Important Radionuclide Species Via Surface-Enhanced Raman Scattering (SERS)

    SciTech Connect (OSTI)

    Dai, Sheng; Bao, Li-Li; Mahurin, Shannon; Gu, Baohua

    2004-03-31T23:59:59.000Z

    Selective and sensitive detection and characterization of radionuclide contaminants in subsurface environments is essential to safely and to cost-effectively locate, treat, isolate or destroy contaminants encountered in DOE's environmental cleanup activity. Currently, techniques for monitoring and characterizing radionuclides rely primarily on liquid scintillation counting, ICP-MS and some limited use of the spectrofluorimetry based on fluorescence of radionuclide species under laser or UV excitation. These techniques require chemical handling, e.g., the use of complexing media, scintillation cocktails and phosphoric acids, in order to enhance signals. Furthermore, only fluorescent radionuclides (U22O+, Cm(III) and Am(III)) can be detected by the last technique. Many environmentally-important radionuclides such as plutonium, neptunium and technetium species have no strong fluorescence signals and, therefore, can not be characterized via fluorescence spectroscopy. The research presented serves to replace existing radionuclide-detection techniques through the development of a novel surface enhanced Raman scattering (SERS) spectroscopy to selectively and sensitively monitor and characterize the chemical speciation of radionuclides at trace levels. The SERS technique permits both of these measurements to be made simultaneously and results in significant improvement over current methods in reducing time of analysis, cost and sample manipulation.

  2. Application of Raman spectroscopy to identification and sorting of post-consumer plastics for recycling

    DOE Patents [OSTI]

    Sommer, Edward J. (Nashville, TN); Rich, John T. (Lebanon, TN)

    2001-01-01T23:59:59.000Z

    A high accuracy rapid system for sorting a plurality of waste products by polymer type. The invention involves the application of Raman spectroscopy and complex identification techniques to identify and sort post-consumer plastics for recycling. The invention reads information unique to the molecular structure of the materials to be sorted to identify their chemical compositions and uses rapid high volume sorting techniques to sort them into product streams at commercially viable throughput rates. The system employs a laser diode (20) for irradiating the material sample (10), a spectrograph (50) is used to determine the Raman spectrum of the material sample (10) and a microprocessor based controller (70) is employed to identify the polymer type of the material sample (10).

  3. The effect of external magnetic field on the Raman peaks in manganites

    SciTech Connect (OSTI)

    Sahu, A. K., E-mail: ajitsahu@seemantaengg.ac.in [Seemanta Engineering College, Jharpokharia, Mayurbhanj-757086, Odisha (India); Rout, G. C. [School of Applied Sciences (Physics), KIIT University, Bhubaneswar-7561024 (India)

    2014-04-24T23:59:59.000Z

    We report here a microscopic theoretical model study exhibiting the effect of external magnetic field on the Raman excitation peaks in the CMR manganite system. The Hamiltonian consists of Jahn-Teller (J-T) distortion in e{sub g} band, the double exchange interaction and the Heisenberg spin-spin interaction. Further the phonons are coupled to e{sub g} band electrons, J-T distorted e{sub g} band and the double exchange interaction. The Raman spectral intensity is calculated from the imaginary part of the phonon Green function. The spectra exhibits three peaks besides a very weak high energy peak. The magnetic field effect on these peaks are reported.

  4. Stimulated Raman Scattering and Nonlinear Focusing of High-Power Laser Beams Propagating in Water

    E-Print Network [OSTI]

    Hafizi, B; Penano, J R; Gordon, D F; Jones, T G; Helle, M H; Kaganovich, D

    2015-01-01T23:59:59.000Z

    The physical processes associated with propagation of a high-power (power > critical power for self-focusing) laser beam in water include nonlinear focusing, stimulated Raman scattering (SRS), optical breakdown and plasma formation. The interplay between nonlinear focusing and SRS is analyzed for cases where a significant portion of the pump power is channeled into the Stokes wave. Propagation simulations and an analytical model demonstrate that the Stokes wave can re-focus the pump wave after the power in the latter falls below the critical power. It is shown that this novel focusing mechanism is distinct from cross-phase focusing. While discussed here in the context of propagation in water, the gain-focusing phenomenon is general to any medium supporting nonlinear focusing and stimulated forward Raman scattering.

  5. Fiber optic apparatus for detecting molecular species by surface enhanced Raman spectroscopy

    DOE Patents [OSTI]

    Angel, S.M.; Sharma, S.K.

    1988-11-01T23:59:59.000Z

    Optrode apparatus for detecting constituents of a fluid medium includes an optical fiber having a metal coating on at least a portion of a light transmissive core. The metal is one, such as silver, gold or copper, which enhances emission of Raman signal frequencies by molecules adsorbed on the surface of the coating when monochromatic probe light of a different frequency is scattered by such molecules and the metal coating is sufficiently thin to transmit light between the absorbed molecules and the core of the fiber. Probe light is directed into one end of the fiber and a detector analyzes light emitted from the fiber for Raman frequencies that identify one or more particular molecular species. In one form, the optrode may function as a working electrode of an electrochemical cell while also serving to detect the products of oxidation or reduction reactions which occur at the electrode surface. 6 figs.

  6. Fiber optic apparatus for detecting molecular species by surface enhanced Raman spectroscopy

    DOE Patents [OSTI]

    Angel, S.M.; Sharma, S.K.

    1987-11-30T23:59:59.000Z

    Optrode apparatus for detecting constituents of a fluid medium includes an optical fiber having a metal coating on at least a portion of a light transmissive core. The metal is one, such as silver, gold or copper, which enhances emission of Raman signal frequencies by molecules adsorbed on the surface of the coating when monochromatic probe light of a different frequency is scattered by such molecules and the metal coating is sufficiently thin to transmit light between the adsorbed molecules and the core of the fiber. Probe light is directed into one end of the fiber and a detector analyzes light emitted from the fiber for Raman frequencies that identify one or more particular molecular species. In one form, the optrode may function as a working electrode of an electrochemical cell while also serving to detect the products of oxidation or reduction reactions which occur at the electrode surface. 6 figs.

  7. Spatial mode structure of stimulated Stokes emission from a Raman generator

    SciTech Connect (OSTI)

    Carlsten, J.L.; Rifkin, J.; MacPherson, D.C.

    1986-10-01T23:59:59.000Z

    The spatial structure of the stimulated Stokes emission from a H/sub 2/ Raman generator has been accurately determined by using a linear photodiode array and imaging techniques. The diffraction-limited pump beam was obtained by spatially clipping the output of an injection-locked XeCl laser. The spatial profiles of the stimulated Stokes beam are compared with the predictions of Yariv's theory of propagation in a quadratic gain medium applied to Raman scattering. (A. Yariv, Quantum Electronics (Wiley, New York, 1975)). While the theory compares well with the experimental data at low intensities, the spatial profile develops features at higher intensities that are not predicted by the simple theory.

  8. Time evolution studies of laser induced chemical changes in InAs nanowire using Raman spectroscopy

    SciTech Connect (OSTI)

    Pal, Suparna; Aggarwal, R.; Kumari Gupta, Vandna; Ingale, Alka [Laser Physics Application Section, Raja Ramanna Centre for Advanced Technology, Indore 452013, MP (India)

    2014-07-07T23:59:59.000Z

    We report the study of time evolution of chemical changes on the surface of an InAs nanowire (NW) on laser irradiation in different power density regime, using Raman spectroscopy for a time span of 8–16 min. Mixture of metastable oxides like InAsO{sub 4,} As{sub 2}O{sub 3} are formed upon oxidation, which are reflected as sharp Raman peaks at ?240–254 and 180–200?cm{sup ?1}. Evidence of removal of arsenic layer by layer is also observed at higher power density. Position controlled laser induced chemical modification on a nanometer scale, without changing the core of the NW, can be useful for NW based device fabrication.

  9. Studies of ground-state dynamics in isolated species by ionization-detected stimulated Raman techniques

    SciTech Connect (OSTI)

    Felker, P.M. [Univ. of California, Los Angeles (United States)

    1993-12-01T23:59:59.000Z

    First, the author aims to develop methods of nonlinear Raman spectroscopy for application in studies of sparse samples. Second, the author wishes to apply such methods to structural and dynamical studies of species (molecules, complexes, and clusters) in supersonic molecular beams. In the past year, the author has made progress in several areas. The first pertains to the application of mass-selective ionization-detected stimulated Raman spectroscopies (IDSRS) to the size-specific vibrational spectroscopy of solute-solvent{sub n} clusters. The second involves the application of IDSRS methods to studies of jet-cooled benzene clusters. The third pertains to the use of IDSRS methods in the study of intermolecular vibrational transitions in van der Waals complexes.

  10. Laser irradiation of carbon nanotube films: Effects and heat dissipation probed by Raman spectroscopy

    SciTech Connect (OSTI)

    Mialichi, J. R.; Brasil, M. J. S. P.; Iikawa, F. [Instituto de Fisica 'Gleb Wataghin,' Unicamp, Campinas, 13083-859 Sao Paulo (Brazil); Verissimo, C.; Moshkalev, S. A. [Centro de Componentes Semicondutores, Unicamp, Campinas, 13083-870 Sao Paulo (Brazil)

    2013-07-14T23:59:59.000Z

    We investigate the thermal properties of thin films formed by single- and multi-walled carbon nanotubes submitted to laser irradiation using Raman scattering as a probe of both the tube morphology and the local temperature. The nanotubes were submitted to heating/cooling cycles attaining high laser intensities ({approx}1.4 MW/cm{sup 2}) under vacuum and in the presence of an atmosphere, with and without oxygen. We investigate the heat diffusion of the irradiated nanotubes to their surroundings and the effect of laser annealing on their properties. The presence of oxygen during laser irradiation gives rise to an irreversible increase of the Raman efficiency of the carbon nanotubes and to a remarkable increase of the thermal conductivity of multi-walled films. The second effect can be applied to design thermal conductive channels in devices based on carbon nanotube films using laser beams.

  11. Raman Scattering of Water and Photoluminescence of Pollutants Arising from Solid-Water Interaction

    E-Print Network [OSTI]

    Vallée, P; Ghomi, M; Jouanne, M; Vall\\'{e}e, Philippe; Lafait, Jacques; Ghomi, Mahmoud; Jouanne, Michel

    2003-01-01T23:59:59.000Z

    Systematic Raman experiments performed on water and water-ethanol samples, stored in different containers (fused silica, polypropylene, soda-lime glass type III) for several hours, have shown that the luminescence contribution to the Raman signal fluctuations is directly related to the container composition. Intensity fluctuations as large as 98%, have been observed in the spectral regions corresponding to the both water intramolecular and intermolecular vibrations, despite the fact that the wavenumbers of the modes remained unchanged. We undoubtedly attribute these fluctuations to a luminescence phenomenon on the basis of : i) the absence of such effect in the anti-Stokes domain, ii) its dependence on the excitation laser wavelength, iii) other relevant photoluminescence experiments. This luminescence is attributed to pollutants at ultra-low concentration coming from the different containers.

  12. Shifting of infrared radiation using rotational raman resonances in diatomic molecular gases

    DOE Patents [OSTI]

    Kurnit, Norman A. (Santa Fe, NM)

    1980-01-01T23:59:59.000Z

    A device for shifting the frequency of infrared radiation from a CO.sub.2 laser by stimulated Raman scattering in either H.sub.2 or D.sub.2. The device of the preferred embodiment comprises an H.sub.2 Raman laser having dichroic mirrors which are reflective for 16 .mu.m radiation and transmittive for 10 .mu.m, disposed at opposite ends of an interaction cell. The interaction cell contains a diatomic molecular gas, e.g., H.sub.2, D.sub.2, T.sub.2, HD, HT, DT and a capillary waveguide disposed within the cell. A liquid nitrogen jacket is provided around the capillary waveguide for the purpose of cooling. In another embodiment the input CO.sub.2 radiation is circularly polarized using a Fresnel rhomb .lambda./4 plate and applied to an interaction cell of much longer length for single pass operation.

  13. Surface-enhanced raman medical probes and system for disease diagnosis and drug testing

    DOE Patents [OSTI]

    Vo-Dinh, Tuan (Knoxville, TN)

    1999-01-01T23:59:59.000Z

    A probe for a surface-enhanced Raman scattering spectrometer includes a member of optically transmissive material for receiving the excitation radiation from a laser and for carrying the radiation emitted from a specimen to a detector. An end of the member for placing against the specimen has a coating that produces surface enhancement of the specimen during Raman scattering spectroscopic analysis. Specifically the coating is formed by a first layer of microparticles on the member and a metal layer over the first layer. The first layer may form a microstructure surface over which a metal layer is applied. Alternatively the coating may be a material containing microparticles of a metal. An optional layer of a material may be applied to the metal layer to concentrate onto the probe compounds of analytical interest onto the probe.

  14. Surface-enhanced Raman medical probes and system for disease diagnosis and drug testing

    DOE Patents [OSTI]

    Vo-Dinh, T.

    1999-01-26T23:59:59.000Z

    A probe for a surface-enhanced Raman scattering spectrometer includes a member of optically transmissive material for receiving the excitation radiation from a laser and for carrying the radiation emitted from a specimen to a detector. An end of the member for placing against the specimen has a coating that produces surface enhancement of the specimen during Raman scattering spectroscopic analysis. Specifically the coating is formed by a first layer of microparticles on the member and a metal layer over the first layer. The first layer may form a microstructure surface over which a metal layer is applied. Alternatively the coating may be a material containing microparticles of a metal. An optional layer of a material may be applied to the metal layer to concentrate onto the probe compounds of analytical interest onto the probe. 39 figs.

  15. Entangled valence electron-hole dynamics revealed by stimulated attosecond x-ray Raman scattering

    SciTech Connect (OSTI)

    Healion, Daniel; Zhang, Yu; Biggs, Jason D.; Govind, Niranjan; Mukamel, Shaul

    2012-09-06T23:59:59.000Z

    We show that broadband x-ray pulses can create wavepackets of valence electrons and holes localized in the vicinity of a selected atom (nitrogen, oxygen or sulfur in cysteine) by resonant stimulated Raman scattering. The subsequent dynamics reveals highly correlated motions of entangled electrons and hole quasiparticles. This information goes beyond the time-dependent total charge density derived from x-ray diffraction.

  16. Molecular cavity optomechanics: a theory of plasmon-enhanced Raman scattering

    E-Print Network [OSTI]

    Philippe Roelli; Christophe Galland; Nicolas Piro; Tobias J. Kippenberg

    2014-07-06T23:59:59.000Z

    The exceptional enhancement of Raman scattering cross-section by localized plasmonic resonances in the near-field of metallic surfaces, nanoparticles or tips has enabled spectrocopic fingerprinting of single-molecules and is widely used in material, chemical and biomedical analysis. Contrasting with this overwhelming practical success, conventional theories based on electromagnetic "hot spots" and electronic or chemical effects cannot account for all experimental observations. Here we present a novel theory of plasmon-enhanced Raman scattering by mapping the problem to cavity optomechanics. Using FEM and DFT simulations we calculate the optomechanical vacuum coupling rate between individual molecules and hot spots of metallic dimers. We find that dynamical backaction of the plasmon on the vibrational mode can lead to amplification of molecular vibrations under blue-detuned laser excitation, thereby revealing an enhancement mechanism not contemplated be- fore. The optomechanical theory provides a quantitative framework for the calculation of enhanced cross-sections, recovers known results, and enables the design of novel systems that leverage dynamical backaction to achieve additional, mode-selective enhancement. It yields a new understanding of plasmon-enhanced Raman scattering and opens a route to molecular quantum optomechanics.

  17. Non-destructive Identification of Individual Leukemia Cells by Optical Trapping Raman Spectroscopy

    SciTech Connect (OSTI)

    Chan, J W; Taylor, D S; Lane, S; Zwerdling, T; Tuscano, J; Huser, T

    2007-03-05T23:59:59.000Z

    Currently, a combination of technologies is typically required to assess the malignancy of cancer cells. These methods often lack the specificity and sensitivity necessary for early, accurate diagnosis. Here we demonstrate using clinical samples the application of laser trapping Raman spectroscopy as a novel approach that provides intrinsic biochemical markers for the noninvasive detection of individual cancer cells. The Raman spectra of live, hematopoietic cells provide reliable molecular fingerprints that reflect their biochemical composition and biology. Populations of normal T and B lymphocytes from four healthy individuals, and cells from three leukemia patients were analyzed, and multiple intrinsic Raman markers associated with DNA and protein vibrational modes have been identified that exhibit excellent discriminating power for cancer cell identification. A combination of two multivariate statistical methods, principal component analysis (PCA) and linear discriminant analysis (LDA), was used to confirm the significance of these markers for identifying cancer cells and classifying the data. The results indicate that, on average, 95% of the normal cells and 90% of the patient cells were accurately classified into their respective cell types. We also provide evidence that these markers are unique to cancer cells and not purely a function of differences in their cellular activation.

  18. CuAl{sub 2} revisited: Composition, crystal structure, chemical bonding, compressibility and Raman spectroscopy

    SciTech Connect (OSTI)

    Grin, Yuri [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, 01187 Dresden (Germany)]. E-mail: grin@cpfs.mpg.de; Wagner, Frank R. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, 01187 Dresden (Germany); Armbruester, Marc [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, 01187 Dresden (Germany); Kohout, Miroslav [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, 01187 Dresden (Germany); Leithe-Jasper, Andreas [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, 01187 Dresden (Germany); Schwarz, Ulrich [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, 01187 Dresden (Germany); Wedig, Ulrich [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstr. 1, 70569 Stuttgart (Germany); Georg von Schnering, Hans [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstr. 1, 70569 Stuttgart (Germany)

    2006-06-15T23:59:59.000Z

    The structure of CuAl{sub 2} is usually described as a framework of base condensed tetragonal antiprisms [CuAl{sub 8/4}]. The appropriate symmetry governed periodic nodal surface (PNS) divides the space of the structure into two labyrinths. All atoms are located in one labyrinth, whereas the second labyrinth seems to be 'empty'. The bonding of the CuAl{sub 2} structure was analyzed by the electron localization function (ELF), crystal orbital Hamiltonian population (COHP) analysis and Raman spectroscopy. From the ELF representation it is seen, that the 'empty' labyrinth is in fact the place of important covalent interactions. ELF, COHP in combination with high-pressure X-ray diffraction and Raman spectroscopy show that the CuAl{sub 2} structure is described best as a network built of interpenetrating graphite-like nets of three-bonded aluminum atoms with the copper atoms inside the tetragonal-antiprismatic cavities. - Graphical abstract: Atomic interactions in the crystal structure of the intermetallic compound CuAl{sub 2}: Three-bonded aluminum atoms form interpenetrating graphite-like nets. The copper atoms are located in the channels of aluminum network by means of three-center bonds. The bonding model is in agreement with the result of polarized Raman spectroscopy and high-pressure X-ray powder diffraction.

  19. Curvature-induced D-band Raman scattering in folded graphene This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Curvature-induced D-band Raman scattering in folded graphene This article has been downloaded from.1088/0953-8984/22/33/334205 Curvature-induced D-band Raman scattering in folded graphene* Awnish K Gupta1 , Cristiano Nisoli2 , Paul E Micro-Raman scattering from folds in single-layer graphene sheets finds a D-band at the fold for both

  20. Efficient "on-the-fly" calculation of Raman spectra from \\textit{ab-initio} molecular dynamics: Application to hydrophobic/hydrophilic solutes in bulk water

    E-Print Network [OSTI]

    Partovi-Azar, Pouya

    2015-01-01T23:59:59.000Z

    We present a computational method to accurately calculate Raman spectra from first principles with an at least one order of magnitude higher efficiency. This scheme thus allows to routinely calculate finite-temperature Raman spectra "on-the-fly" by means of \\textit{ab-initio} molecular dynamics simulations. To demonstrate the predictive power of this approach we investigate the effect of hydrophobic and hydrophilic solutes in water solution on the infrared and Raman spectra.

  1. Compared Raman study of the phase transitions in K2ZnCl4 and Rb2ZnCl4, Rb2ZnBr4, K2SeO4

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    787 Compared Raman study of the phase transitions in K2ZnCl4 and Rb2ZnCl4, Rb2ZnBr4, K2SeO4 M to the incommensurate phase is discussed for the four compounds K2SeO4, K2ZnCl4, Rb2ZnCl4 and Rb2ZnBr4 on the basis measurements on K2ZnC'4 known to exhibit successive phase transitions similar to those of K2SeO4

  2. Scanning lidar based atmospheric monitoring for fluorescence detectors of cosmic showers

    E-Print Network [OSTI]

    Zavrtanik, Marko

    .elsevier.com/locate/astropart #12;the integral of EM particle density Nem along the shower direction x, Eem ¼ K Z Nemðx�dx ð1� with K % 2:2 MeV cm2 /g, where x is measured in units of longitudinal air density (g/cm2 ). Eem

  3. Lidar Remote Sensing of the Canopy Structure and Biophysical Properties of

    E-Print Network [OSTI]

    Lefsky, Michael

    infrequently measured, from either field or remote used in predictive equations generated by the stepwise Laboratory, Pacific exceeds 3 has been less successful (e.g., Sader et al., Northwest Research Station, Corvallis Smithsonian Environmental Research Center, Edgewater, primarily in the temperate and tropical

  4. How Graphene Slides: Measurement and Theory of Strain-Dependent Frictional Forces between Graphene and SiO2

    E-Print Network [OSTI]

    How Graphene Slides: Measurement and Theory of Strain- Dependent Frictional Forces between Graphene, and adhesion are interwoven in determining how graphene responds when pulled across a substrate. Using Raman spectroscopy of circular, graphene-sealed microchambers under variable external pressure, we demonstrate

  5. Combined Quantum Chemical/Raman Spectroscopic Analyses of Li+ Cation Solvation: Cyclic Carbonate Solvents - Ethylene Carbonate and Propylene Earbonate

    SciTech Connect (OSTI)

    Allen, Joshua L.; Borodin, Oleg; Seo, D. M.; Henderson, Wesley A.

    2014-12-01T23:59:59.000Z

    Combined computational/Raman spectroscopic analyses of ethylene carbonate (EC) and propylene carbonate (PC) solvation interactions with lithium salts are reported. It is proposed that previously reported Raman analyses of (EC)n-LiX mixtures have utilized faulty assumptions. In the present studies, density functional theory (DFT) calculations have provided corrections in terms of both the scaling factors for the solvent's Raman band intensity variations and information about band overlap. By accounting for these factors, the solvation numbers obtained from two different EC solvent bands are in excellent agreement with one another. The same analysis for PC, however, was found to be quite challenging. Commercially available PC is a racemic mixture of (S)- and (R)-PC isomers. Based upon the quantum chemistry calculations, each of these solvent isomers may exist as multiple conformers due to a low energy barrier for ring inversion, making deconvolution of the Raman bands daunting and inherently prone to significant error. Thus, Raman spectroscopy is able to accurately determine the extent of the EC...Li+ cation solvation interactions using the provided methodology, but a similar analysis of PC...Li+ cation solvation results in a significant underestimation of the actual solvation numbers.

  6. Note: Deep ultraviolet Raman spectrograph with the laser excitation line down to 177.3 nm and its application

    SciTech Connect (OSTI)

    Jin, Shaoqing [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China) [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Fan, Fengtao; Guo, Meiling; Zhang, Ying; Feng, Zhaochi, E-mail: zcfeng@dicp.ac.cn, E-mail: canli@dicp.ac.cn; Li, Can, E-mail: zcfeng@dicp.ac.cn, E-mail: canli@dicp.ac.cn [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)] [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2014-04-15T23:59:59.000Z

    Deep UV Raman spectrograph with the laser excitation line down to 177.3 nm was developed in this laboratory. An ellipsoidal mirror and a dispersed-subtractive triple monochromator were used to collect and disperse Raman light, respectively. The triple monochromator was arranged in a triangular configuration with only six mirrors used. 177.3 nm laser excited Raman spectrum with cut-off wavenumber down to 200 cm{sup ?1} and spectral resolution of 8.0 cm{sup ?1} can be obtained under the condition of high purity N{sub 2} purging. With the C–C ? bond in Teflon selectively excited by the 177.3 nm laser, resonance Raman spectrum of Teflon with good quality was recorded on the home-built instrument and the ?-?{sup *} transition of C–C bond was studied. The result demonstrates that deep UV Raman spectrograph is powerful for studying the systems with electronic transition located in the deep UV region.

  7. Long-range micro-pulse aerosol lidar at 1.5 um with an up-conversion single-photon detector

    E-Print Network [OSTI]

    Haiyun Xia; Guoliang Shentu; Mingjia Shangguan; Xiuxiu Xia; Xiaodong Jia; Chong Wang; Jun Zhang; Qiang Zhang; Xiankang Dou; Jianwei Pan

    2014-12-09T23:59:59.000Z

    A micro-pulse lidar at eye-safe wavelength is constructed based on an up-conversion single-photon detector. The ultralow noise detector enables using integration technique to improve the signal-to-noise ratio of the atmospheric backscattering even at daytime. With the pulse energy of 110uJ, the pulse repetition rate of 15 kHz, the optical antenna diameter of 100 mm and integration time of 5 minutes, a horizontal detection range of 7 km is realized. In the demonstration experiment, atmospheric visibility over 24 hours is monitored continuously, with results in accordance with the weather forecasts.

  8. An Epi-Detected Coherent Anti-Stokes Raman Scattering (E-CARS) Microscope with High Spectral Resolution and High Sensitivity

    E-Print Network [OSTI]

    Xie, Xiaoliang Sunney

    LETTERS An Epi-Detected Coherent Anti-Stokes Raman Scattering (E-CARS) Microscope with High-detected coherent anti-Stokes Raman scattering (E-CARS) microscope that uses two synchronized picosecond pulse (CARS) microscopy provides a unique approach to imaging chemical and biological samples by using

  9. W. N. WANGet al.: Laser Raman Studies of Polycrystalline and A-Diamond Films 255 phys. stat. sol. (a) 154,255 (1996)

    E-Print Network [OSTI]

    Bristol, University of

    1996-01-01T23:59:59.000Z

    W. N. WANGet al.: Laser Raman Studies of Polycrystalline and A-Diamond Films 255 phys. stat. sol, Transducer Systems Division, Wotton-under-Edge4)(d) Laser Raman Studies of Polycrystalline and Amorphic Diamond Films W. N. WANG(a), N. A. FOX(a), P. W. MAY(b), M. P. KNAPPER(b), G. MEADEN(c), P. G. PARTRIDGE

  10. Substrate doping effects on Raman spectrum of epitaxial graphene on SiC R. Yang, Q. S. Huang, X. L. Chen, G. Y. Zhang,a

    E-Print Network [OSTI]

    Wang, Wei Hua

    Substrate doping effects on Raman spectrum of epitaxial graphene on SiC R. Yang, Q. S. Huang, X. L; published online 2 February 2010 In this paper, we reported a Raman scattering study of epitaxial graphene to the epitaxial graphene. We found that the charge carrier type and concentration of epitaxial graphene can

  11. Vision 20/20: The role of Raman spectroscopy in early stage cancer detection and feasibility for application in radiation therapy response assessment

    SciTech Connect (OSTI)

    Devpura, Suneetha, E-mail: sdevpur1@hfhs.org; Barton, Kenneth N.; Brown, Stephen L.; Siddiqui, Farzan; Chetty, Indrin J. [Department of Radiation Oncology, Henry Ford Hospital, Detroit, Michigan 48202 (United States)] [Department of Radiation Oncology, Henry Ford Hospital, Detroit, Michigan 48202 (United States); Palyvoda, Olena [College of Engineering, Wayne State University, Detroit, Michigan 48202 (United States)] [College of Engineering, Wayne State University, Detroit, Michigan 48202 (United States); Kalkanis, Steven [Department of Neurosurgery, Henry Ford Hospital, Detroit, Michigan 48202 (United States)] [Department of Neurosurgery, Henry Ford Hospital, Detroit, Michigan 48202 (United States); Naik, Vaman M. [Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, Michigan 48128 (United States)] [Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, Michigan 48128 (United States); Naik, Ratna [Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201 (United States)] [Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201 (United States)

    2014-05-15T23:59:59.000Z

    Raman spectroscopy is an optical technique capable of identifying chemical constituents of a sample by their unique set of molecular vibrations. Research on the applicability of Raman spectroscopy in the differentiation of cancerous versus normal tissues has been ongoing for many years, and has yielded successful results in the context of prostate, breast, brain, skin, and head and neck cancers as well as pediatric tumors. Recently, much effort has been invested on developing noninvasive “Raman” probes to provide real-time diagnosis of potentially cancerous tumors. In this regard, it is feasible that the Raman technique might one day be used to provide rapid, minimally invasive real-time diagnosis of tumors in patients. Raman spectroscopy is relatively new to the field of radiation therapy. Recent work involving cell lines has shown that the Raman technique is able to identify proteins and other markers affected by radiation therapy. Although this work is preliminary, one could ask whether or not the Raman technique might be used to identify molecular markers that predict radiation response. This paper provides a brief review of Raman spectroscopic investigations in cancer detection, benefits and limitations of this method, advances in instrument development, and also preliminary studies related to the application of this technology in radiation therapy response assessment.

  12. Raman scattering in organic semiconductors based on erbium biphthalocyanine molecules and chlorine-containing europium-lutetium triphthalocyanine molecules

    SciTech Connect (OSTI)

    Belogorokhov, I. A., E-mail: jugqwerty@mail.ru [Federal State Research and Design Institute for Rare-Metal Industry (Russian Federation); Mamichev, D. A.; Dronov, M. A.; Pushkarev, V. E.; Tomilova, L. G.; Khokhlov, D. R. [Moscow State University (Russian Federation)

    2010-08-15T23:59:59.000Z

    The Raman spectra of semiconductor structures based on erbium biphthalocyanine molecules and chlorine-substituted europium-lutetium triphthalocyanine molecules are studied on excitation with Ar{sup +} laser radiation at the wavelength 514 nm. The data on the spectral position of Raman intensity peaks related to vibronic states of the basic molecular groups forming the semiconductor are obtained. Raman lines irrelevant to the known vibronic states of the basic phthalocyanine molecular groups are observed in the ranges 100-500 and 500-900 cm{sup -1}. It is shown that, in the spectra of triphthalocyanine, some lines are structurally complex and shifted with respect to the characteristic lines of molecular groups by several inverse centimeters.

  13. Combined raman and IR fiber-based sensor for gas detection

    DOE Patents [OSTI]

    Carter, Jerry C; Chan, James W; Trebes, James E; Angel, Stanley M; Mizaikoff, Boris

    2014-06-24T23:59:59.000Z

    A double-pass fiber-optic based spectroscopic gas sensor delivers Raman excitation light and infrared light to a hollow structure, such as a hollow fiber waveguide, that contains a gas sample of interest. A retro-reflector is placed at the end of this hollow structure to send the light back through the waveguide where the light is detected at the same end as the light source. This double pass retro reflector design increases the interaction path length of the light and the gas sample, and also reduces the form factor of the hollow structure.

  14. Numerical investigation of mid-infrared Raman soliton source generation in endless single mode fluoride fibers

    SciTech Connect (OSTI)

    Liu, Lai; Qin, Guan-Shi, E-mail: qings@jlu.edu.cn; Tian, Qi-jun; Zhao, Dan; Qin, Wei-Ping, E-mail: wpqin@jlu.edu.cn [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

    2014-04-28T23:59:59.000Z

    We numerically investigate Raman soliton generation in a fluoride photonic crystal fiber (PCF) pumped by 1.93 ?m femtosecond fiber lasers in order to get widely tunable laser source in the mid-infrared region. The simulated results show that a continuously tunable range (1.93???3.95??m) over 2000?nm is achieved in 1-m-long fluoride PCF pumped by a 1.93??m femtosecond fiber laser with a pulse width of 200 fs. The power conversion efficiency is also calculated and the maximum efficiency can be up to 84.27%.

  15. Production of entanglement in Raman three-level systems using feedback

    E-Print Network [OSTI]

    R. N. Stevenson; A. R. R. Carvalho; J. J. Hope

    2010-01-10T23:59:59.000Z

    We examine the theoretical limits of the generation of entanglement in a damped coupled ion-cavity system using jump-based feedback. Using Raman transitions to produce entanglement between ground states reduces the necessary feedback bandwidth, but does not improve the overall effect of the spontaneous emission on the final entanglement. We find that the fidelity of the resulting entanglement will be limited by the asymmetries produced by vibrations in the trap, but that the concurrence remains above 0.88 for realistic ion trap sizes.

  16. Effect of laser beam filamentation on coexisting stimulated Raman and Brillouin scattering

    SciTech Connect (OSTI)

    Sharma, R. P.; Vyas, Ashish; Kishor Singh, Ram [Centre for Energy Studies, IIT, Delhi 110016 (India)] [Centre for Energy Studies, IIT, Delhi 110016 (India)

    2013-10-15T23:59:59.000Z

    This paper presents the study of stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) when both of these processes are coexisting and pump laser beam initial power is more than filamentation threshold. On account of the ponderomotive nonlinearity, the pump laser beam gets filamented, and both the scattering processes (SRS and SBS) get affected. Simultaneous presence of SRS and SBS (five wave interaction case) also affect the pump filamentation process due to pump depletion. Both the scattering processes (SRS and SBS) are enhanced due to filamentation of laser beam. Results are also compared with the three wave interaction case (either SRS or SBS) with and without filamentation.

  17. Entangled radiation via a Raman-driven quantum-beat laser

    E-Print Network [OSTI]

    Qamar, Sajid; Al-Amri, M.; Qamar, Shahid; Zubairy, M. Suhail

    2009-01-01T23:59:59.000Z

    Entangled radiation via a Raman-driven quantum-beat laser Sajid Qamar,1 M. Al-Amri,2 Shahid Qamar,1,* and M. Suhail Zubairy1,3 1Centre for Quantum Physics, COMSATS Institute of Information Technology, Islamabad 44000, Pakistan 2The National... and Applied Sciences, Nilore, Islamabad, Pakistan. PHYSICAL REVIEW A 80, 033818 #1;2009#2; 1050-2947/2009/80#1;3#2;/033818#1;8#2; ?2009 The American Physical Society033818-1 states, these are the sufficient conditions; however, for two- mode continuous...

  18. A narrow-band speckle-free light source via random Raman lasing

    E-Print Network [OSTI]

    Hokr, Brett H; Bixler, Joel N; Dyer, Phillip N; Noojin, Gary D; Redding, Brandon; Thomas, Robert J; Rockwell, Benjamin A; Cao, Hui; Yakovlev, Vladislav V; Scully, Marlan O

    2015-01-01T23:59:59.000Z

    Currently, no light source exists which is both narrow-band and speckle-free with sufficient brightness for full-field imaging applications. Light emitting diodes (LEDs) are excellent spatially incoherent sources, but are tens of nanometers broad. Lasers on the other hand can produce very narrow-band light, but suffer from high spatial coherence which leads to speckle patterns which distort the image. Here we propose the use of random Raman laser emission as a new kind of light source capable of providing short-pulsed narrow-band speckle-free illumination for imaging applications.

  19. Two-dimensional stimulated resonance Raman spectroscopy of molecules with broadband x-ray pulses

    SciTech Connect (OSTI)

    Biggs, Jason D.; Zhang Yu; Healion, Daniel; Mukamel, Shaul [Department of Chemistry, University of California, Irvine, California 92697-2025 (United States)

    2012-05-07T23:59:59.000Z

    Expressions for the two-dimensional stimulated x-ray Raman spectroscopy (2D-SXRS) signal obtained using attosecond x-ray pulses are derived. The 1D- and 2D-SXRS signals are calculated for trans-N-methyl acetamide (NMA) with broad bandwidth (181 as, 14.2 eV FWHM) pulses tuned to the oxygen and nitrogen K-edges. Crosspeaks in 2D signals reveal electronic Franck-Condon overlaps between valence orbitals and relaxed orbitals in the presence of the core-hole.

  20. Methods and systems for Raman and optical cross-interrogation in flow-through silicon membranes

    DOE Patents [OSTI]

    Bond, Tiziana C.; Letant, Sonia E.

    2014-09-09T23:59:59.000Z

    Cross-interrogating photonic detection systems and methods are shown. A flow through photonic crystal membrane with a surface enhanced Raman scattering (SERS) substrate is provided with pores which are distributed along multiple regions. The pores of one region have walls to which a first type of target specific anchor can be attached, while pores of another region have walls to which a second type of target specific anchor can be attached. An optical arrangement out-of-plane to the SERS substrate is also provided for enhanced sensitivity and identification of target organisms.