Divergence of the radiation from a Raman laser with a slowly relaxing active medium

A theoretical analysis is made of the formation of the angular characteristic of the output radiation from a liquid-nitrogen Raman laser. It is shown that the main mechanism of formation of optical inhomogeneities in the active medium of this laser is the accumulation of vibrationally excited molecules having a high polarizability during the stimulated Raman scattering process. The calculated angular distribution of the output energy agrees with the experimental results.