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Single-shot gas-phase thermometry using pure-rotational hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering
- Source :
- Optics express. 19(16)
- Publication Year :
- 2011
-
Abstract
- High-repetition-rate, single-laser-shot measurements are important for the investigation of unsteady flows where temperature and species concentrations can vary significantly. Here, we demonstrate single-shot, pure-rotational, hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps RCARS) thermometry based on a kHz-rate fs laser source. Interferences that can affect nanosecond (ns) and ps CARS, such as nonresonant background and collisional dephasing, are eliminated by selecting an appropriate time delay between the 100-fs pump/Stokes pulses and the pulse-shaped 8.4-ps probe. A time- and frequency-domain theoretical model is introduced to account for rotational-level dependent collisional dephasing and indicates that the optimal probe-pulse time delay is 13.5 ps to 30 ps. This time delay allows for uncorrected best-fit N2-RCARS temperature measurements with ~1% accuracy. Hence, the hybrid fs/ps RCARS approach can be performed with kHz-rate laser sources while avoiding corrections that can be difficult to predict in unsteady flows.
- Subjects :
- Optics and Photonics
Materials science
Time Factors
Thermometers
Dephasing
Spectrum Analysis, Raman
law.invention
symbols.namesake
Optics
law
Fourier Analysis
business.industry
Temperature
Equipment Design
Nanosecond
Models, Theoretical
Laser
Atomic and Molecular Physics, and Optics
Picosecond
Femtosecond
symbols
Gases
business
Raman spectroscopy
Ultrashort pulse
Raman scattering
Algorithms
Subjects
Details
- ISSN :
- 10944087
- Volume :
- 19
- Issue :
- 16
- Database :
- OpenAIRE
- Journal :
- Optics express
- Accession number :
- edsair.doi.dedup.....22105865ce34585e4326158c47e312e4