Dynamics of radiation generated by single-pass nonlinear amplification of noise in an optically inhomogeneous medium

The method of a quasioptic equation for a transverse correlation function is used in a study of single-pass amplification of radiation from a spontaneous source in an optically inhomogeneous medium which is in the form of a cylinder or a planar layer and is characterized by nonresonant losses under gain saturation conditions. Approximate analytic expressions are deduced for the power of the radiation emerging from the end and side surfaces of the active medium in the two cases of homogeneously and inhomogeneously broadened lines. The angular spectra of stimulated radiation are given. The coefficient representing the refraction losses and the problems of optimal coupling out of the energy via the side surface are discussed.