Research on compensation characteristics of thermal insensitive cavity

The output beam profile from a heat capacity laser is instantaneously changing because of the temperature continually rising during laser shots.In order to improve the focusing capability of heat capacity laser and realize real time controlling of the far field spot,a cube corner array(CCA) is used as a quasi-phase conjugate mirror to realize a passive and real time compensation of the wave front error.The compensation capability of a thermal insensitive cavity with a cube corner array was studied in detail.The structure of the cube corner array resonator was optimized by using an infra-cavity filter to reject the conjugation mode between different cube comers.The energy concentration of the single mode with an infra-cavity filter was improved to 90%, approximately 4.5 times of the multi-modes without the infra-cavity filter.The focusing ability of such a CCA resonator was improved about 10 times of a traditional planner-concave resonator.The simulation and experiment results show that the cube corner array cavity is thermal insensitive,which can increase the focusing ability of a heat capacity laser.