Effects of laser field statistics on coherent anti-Stokes Raman spectroscopy intensities

Abstract

The effects of intensity fluctuations in the frequency-doubled output of a multimode Nd:YAG pump laser on coheren anti-Stokes Raman spectroscopy (CARS) signal generation have been investigated in a crossed-beam, twocolor CARS experiment. Measurements of signal intensity as a function of time delay (small compared with pulse length) in one pump beam show a maximum at zero delay. In measurements on a single unresolved transition, however, the nonresonant signal is enhanced by almost a factor of 2 more than the resonant signal. Our results demonstrate the non-Gaussian nature of the laser field statistics and introduce new considerations into the analysis of experimental CARS spectra.