Calculation of the quality characteristics of adaptive laser systems with phase correction

Approximate expressions are obtained for calculating the main quality characteristics of adaptive systems used in focusing of laser radiation accompanied by phase correction: these characteristics are the average value of the Strehl number and the relative variance of fluctuations of this number. The example of a system with compensation of the average tilt of the phase front is used in estimating the error in the proposed approximations. The general case of different sizes of the measuring and light-emitting apertures is discussed.