Coherent anti-Stokes resonance Raman scattering

The intensity of coherent anti-Stokes resonance Raman scattering (CARRS) is calculated taking into account the resonant absorption of laser and anti-Stokes waves and changes in the molecule population. The resonant absorption causes an alteration of the phase of the laser wave leading to a decrease and periodic behaviour of the anti-Stokes intensity. This phase change can be compensated by the choice of a definite wave vector mismatchK, which determines the optimum condition for the CARRS. The optimum angle between the Stokes and the laser propagation direction and the optimum cell length are calculated. The line shape of the CARRS is discussed and used for the explanation of the observed dependence of the CARRS spectra on the laser intensity and the frequency and on the molecule number density. In the case of a O-O excitation the vibrational frequencies of the ground and the excited level are generated simultaneously in the CARRS spectra.