Nonlinearity and Single Shot Noise Problems in CARS (Coherent Antistokes Raman Scattering) Spectroscopy,
DEFENCE RESEARCH ESTABLISHMENT OTTAWA (ONTARIO)
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This paper describes the design and operation of a CARS spectrometer and its use to perform accurate temperature measurements in a simple laboratory flat-flame burner. Instrumental sources of systematic error and noise in CARS temperature measurements are discussed. An analysis of the system noise is presented and the use of the measured noise to perform weighted least mean squares fits of experimental and theoretical CARS spectra is discussed. The use of a weighted fit is shown to markedly improve the precision of single pulse CARS temperature measurements. Finally, incorporation of some recent advances in CARS theory which have resulted in more computationally efficient algorithms for calculating theoretical CARS spectra and their effect on the accuracy of temperature measurements are discussed.
- Atomic and Molecular Physics and Spectroscopy
- Combustion and Ignition