Automatically controlled system for stabilisation of the output power of an Nd:YAG laser with intracavity frequency doubling

An automatically controlled system for stabilisation of the output power of an Nd:YAG laser with intracavity frequency doubling was constructed. This system applied to an industrial laser of the LG-402A type. Active stabilisation of the output radiation was performed by personal-computer control of the pump current and of the thermal conversion regime in the nonlinear element. Algorithms developed for control of the output radiation parameters make it possible to avoid the use of a probe perturbation and to achieve a relative instability of less than 0.5% for the integral intensity of the second-harmonic radiation.