Amplification of spontaneous radiation in a nonlinear active medium

Vladimir K. Ladagin, Стариков Федор Алексеевич, Vitali D. Urlin

Nickolai N. Elkin, Vladimir V. Likhanskii, Anatoly P. Napartovich

W. Lukosz, P P Herrmann

George C. Baldwin

A. L. Belov, F. V. Bunkin, Sergei I Yakovlenko

A one-dimensional radiative transfer model is used in a study of the amplification of spontaneous radiation as a result of a population-inverted ionic transition pumped by recombination. The problem of such transfer is solved analytically in the steady-state case and it is shown that the intensities of the radiation emitted in both directions are the same irrespective of the distribution of the unsaturated gain over the length of the active medium. Numerical calculations are reported of the stage of establishment of light fluxes. It is shown that during this transient stage a nonlinear interaction between opposite light fluxes is responsible for nonmonotonic behavior of the output radiation intensity. The problem of amplification in a traveling pump wave is treated analytically.

Стариков Федор Алексеевич

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.