5 February 1999 Infrared degenerate four-wave mixing and resonance-enhanced stimulated Raman scattering in small molecules
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Proceedings Volume 3732, ICONO '98: Laser Spectroscopy and Optical Diagnostics: Novel Trends and Applications in Laser Chemistry, Biophysics, and Biomedicine; (1999); doi: 10.1117/12.339994
Event: ICONO '98: Laser Spectroscopy and Optical Diagnostics: Novel Trends and Applications in Laser Chemistry, Biophysics, and Biomedicine, 1998, Moscow, Russian Federation
Abstract
Infrared degenerate four-wave mixing spectroscopy (IR-DFWM) has been employed to study the molecules acetylene (C2H2), ammonia (NH3), methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) in a cell under equilibrium conditions and cooled in free jet expansions. For methane at room temperature the detection limit was 2 X 1012 molecules per cm3 and quantum state, enabling the detection of trace species with a spatial resolution of 1 mm2 X 30 mm. In an attempt to study transitions in the v1 + v3 and 2v2 + v3 combination bands of CO2 or N2O, it was not possible to observe any DFWM signal. Instead a surprisingly strong, backward and forward directed emission was found which could not be attributed to the DFWM process. Our investigations lead to the conclusion that the emission can be explained by stimulated Raman scattering, resonantly enhanced by transitions to the combination levels v1 + v3 and 2v2 + v3. This process seems to suppress the generation of DFWM signal.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Dirk Voelkel, J. Marques, Friedrich Huisken, Yu. L. Chuzavkov, S. N. Orlov, Yu. N. Polivanov, V. V. Smirnov, "Infrared degenerate four-wave mixing and resonance-enhanced stimulated Raman scattering in small molecules", Proc. SPIE 3732, ICONO '98: Laser Spectroscopy and Optical Diagnostics: Novel Trends and Applications in Laser Chemistry, Biophysics, and Biomedicine, (5 February 1999); doi: 10.1117/12.339994; https://doi.org/10.1117/12.339994
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KEYWORDS
Molecules

Raman scattering

Infrared radiation

Absorption

Four wave mixing

Signal detection

Methane

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