Spatial variation of gain and saturation in a fast axial flow CO_2 laser amplifier

Abstract

The spatial variation of gain and saturation is analyzed in weakly and heavily saturated cases for a fast axial flow (FAF) CO(2) laser amplifier with laser gas in laminar and turbulent flow regions. Expressiong the laser parameters by fourth-order even functions of the radial distance, the development of the amplified radiation is predicted and compared successfully to the experimental results for the 10P(18) line. The distinctive feature of a FAF system is enhancement of the gain and saturation irradiance as well as the mode volume. The condition of spatial soliton is also discussed in a heavily saturated case.