Laser pretreatment parameters optimization of KDP crystal

KDP crystal is the chief choice of frequency multiplier in high power laser system. Laser pretreatment is usually used to improve the damage probability of KDP element, the pretreatment process is more time-consuming, and it is of great significance to the engineering application to improve the pretreatment efficiency. KDP damage performance preconditioned by different laser pretreatment protocols was investigated, every protocol had three key parameters: laser radiation fluence, irradiated laser shots, and energy steps. By analyzing the condition parameters and the resultant damage performance, effect of every parameter on damage performance was discovered, and it is found that the same pretreatment performance can be achieved by using different energy steps, and laser pretreatment protocol was optimized by using variable energy steps instead of fixing one. Experimental results show that the variable energy steps protocol achieves total laser shots savings of 33%. The results would be benefit for KDP elements pretreatment process.