Bandwidth optimization of femtosecond pure-rotational coherent anti-Stokes Raman scattering by pump/Stokes spectral focusing.
A simple spectral focusing scheme for bandwidth optimization of gas-phase rotational coherent anti-Stokes Raman scattering (CARS) spectra is presented. The method is useful when femtosecond pump/Stokes preparation of the Raman coherence is utilized. The approach is of practical utility when working with laser pulses that are not strictly transform limited, or when windows or other sources of pulse chirp may be present in the experiment. A delay between the femtosecond preparation pulses is introduced to shift the maximum Raman preparation away from zero frequency and toward the Stokes or anti-Stokes side of the spectrum with no loss in total preparation bandwidth. Shifts of 100 cm-1 or more are attainable and allow for enhanced detection of high-energy (150-300 cm-1) rotational Raman transitions at near transform-limited optimum sensitivity. A simple theoretical treatment for the case of identical pump and Stokes pulses with linear frequency chirp is presented. The approach is then demonstrated experimentally for typical levels of transform-limited laser performance obtained our laboratory with nonresonant CARS in argon and Raman-resonant spectra from a lean H2/air flat flame.
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Engineering Sciences Center
- Publication Date:
- OSTI Identifier:
- Report Number(s):
Journal ID: ISSN 0003-6935; 533705
- Grant/Contract Number:
- Accepted Manuscript
- Journal Name:
- Applied Optics
- Additional Journal Information:
- Journal Volume: 53; Journal Issue: 28; Journal ID: ISSN 0003-6935
- Optical Society of America (OSA)
- Research Org:
- Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Org:
- USDOE National Nuclear Security Administration (NNSA), Office of Defense Science (NA-113)
- Country of Publication:
- United States
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
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