Technique for Thermal Lenses Measuring Using the Gerchberg-Saxton Algorithm in High Power Laser Systems

In this paper, we demonstrate a technique for measuring the thermally induced phase of a beam by using the Gerchberg-Saxton algorithm. It is shown that the method performs well when measuring optically transparent and highly scattering media, and also that it can be used to make comparative characteristics of different samples absorption coefficients and to measure the aberrations of the output beam. The dependence of the thermal lens dioptric power on the radiation power was investigated in a TGG crystal and ceramic Tb₂O₃, and a comparison of the thermal effects was made. Additionally, the possibility of estimating of the aberrations of thermal lenses was shown.