Simple method of measurement of phase distortions in laser amplifiers

Two alternative methods for determining phase distortions of radiation in the heated active element of a high-power Nd:glass laser are compared: direct phase measurement with the Mach–Zehnder interferometer and phase front reconstruction from measured distributions of depolarization factor. It is shown that the latter method can quite quickly and accurately determine the wavefront distortions of laser radiation with minimal interference to the optical scheme of the laser.