Conversion of energy of Gaussian light pulses in stimulated Raman and Brillouin scattering

The case of pump pulses with Gaussian space-time intensity distributions is considered in the quasistatic approximation. Expressions are obtained for the power, energy, efficiency, and duration of pulses of the nth Stokes component of the stimulated Raman scattering (n = I, 2 ...). Similar calculations are also made for the stimulated Brillouin scattering. Theoretical estimates are obtained of the maximum conversion efficiency in the stimulated Raman scattering; it is shown that the power efficiency is higher than the energy efficiency. The influence of the attenuation of light in matter, length of the scattering region, and spatial profile of the pump beam on the structure of the stimulated Raman spectrum is considered. The computer-calculated dependences of the energy characteristics of the stimulated Raman scattering in the liquid nitrogen on the pump wavelength (1.06, 0.69, and 0.53 μ) are given. It is shown that some of the theoretical estimates obtained are in good agreement with the experimental results.