Initial Damage and Damage Growth of KDP Crystals Induced by 355 nm Pulse Laser

Bulk damage of potassium dihydrogen phosphate (KDP) crystals induced by high power UV pulse laser irradiation is the main factor limiting inertial confinement fusion (ICF) laser output performance. In this study, investigated KDP crystal bulk damage behavior induced by nanosecond 355 nm laser is investigated. Bulk damage density exponentially increases with the increasing laser flux. Damage manifests as a central hole and radially extends crack. The bulk damage size of sample can be significantly reduced by the laser pretreatment. When damage density reachs 3 mm(-3), functional damage criterion is observed. From the reseach on the damage growth process, it can be further found that there is a certain probability to induce the density and size growth of damage points for KDP crystal when the laser energy density is over 10Jcm(-2). Moreover, the laser pretreatment had no effect on the behavior. The outcomes of this study provide a reference for optimizing KDP crystal application in high power lasers.