Dependence of laser properties on statistical distortions of active medium

Experimental results obtained with a high-power CO2 laser show strong influences of the gas flowing state on beam quality and output power. To estimate the influences of statistical phase and gain distortions on laser performance a theoretical model was presented. Using the model the dependencies of beam quality, the Strehl ratio and output power on the dimension and the strength of distortions were numerically investigated. In general, the beam properties of unstable resonators is hardly influenced by the local gain fluctuation. The output power, the beam quality and the Strehl ratio of the unstable resonator decrease with increasing phase distortion strength. For a constant phase distortion strength the output power of unstable resonator is nearly independently of the distortion dimension. For a given phase distortion strength the decrement in beam quality is larger at large magnifications. The decrement in the output power due to the phase distortions is nearly independently of the magnification.