An ultrasensitive detection technique for tunable diode laser spectrometers: Application to detection of NO{sub 2} and H{sub 2}O
- Physical Sciences Inc., Andover, MA (United States)
Recent advances in room-temperature tunable diode lasers and ultrasensitive electronic noise quieting detection techniques now enable a new generation of compact, optoelectronic, ultrasensitive trace gas sensors. These advances are key to producing sensors capable of routine and extended field use. The authors achieve near shot noise-limited signal detection using a novel, balanced ratiometric detector (BRD) which permits measurements of absorbances of 1:10{sup 6}. High sensitivity is achieved by coupling this technology with an extended optical pathlength. The BRD is characterized by a wide linear dynamic range. A 10 Hz measurement rate enables ground level flux measurements or airborne concentration measurements. The authors will present an overview of two applications of their ultrasensitive detection technology to in situ atmospheric sensing. The first sensor is being developed to monitor boundary layer NO{sub 2} fluxes. This sensor operates at 670 nm, utilizes an open multipass optical cell, and has a sub-ppbv detection sensitivity. The second sensor is an airborne, near IR (1.39 {micro}m) diode laser hygrometer. The sensor uses an in-situ air measurement probe housing a 50 cm, open optical path to circumvent problems inherent in extractive sampling. The sensor is capable of measuring water vapor throughout the troposphere and has a sensitivity of 0.5 ppmv at the tropopause.
- OSTI ID:
- 500933
- Report Number(s):
- CONF-960848-; ISBN 0-8194-2222-3; TRN: IM9732%%161
- Resource Relation:
- Conference: Denver `96: 1. conference on space processing of materials, at SPIE International Society for Optical Engineering (SPIE) annual international symposium on optical science, engineering, and instrumentation, Denver, CO (United States), 4-9 Aug 1996; Other Information: PBD: 1996; Related Information: Is Part Of Application of tunable diode and other infrared sources for atmospheric studies and industrial process monitoring; Fried, A. [ed.] [National Center for Atmospheric Research, Boulder, CO (United States). Atmospheric Chemistry Div.]; PB: 293 p.; Proceedings/SPIE, Volume 2834
- Country of Publication:
- United States
- Language:
- English
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