Finite element analysis on influence of micro-nano machined surface impurity on optical performance of crystal

Based on theory of temperature field and thermal stress field around inclusions in KDP crystals, the distribution of crystal temperature field and thermal stress field is analyzed under the influence of micro-nano machined superficial layer’s inclusions. It is found that ions of inclusions absorbing mucl injected laser lead to crystal damages. Inclusions’ sfrong absorbing of laser influenc KDP crystals laser damage threshold. The radius of adverse inclusion is obtained, with which the also inclusion absorbs the maximumenergy and reaches the wighest temperature. In addition, different kinds and different contents of inclusions have different effect on the crystal laser damage threshold．