Improvement of the bulk laser damage threshold of potassium dihydrogen phosphate crystals by ultraviolet irradiation

Potassium dihydrogen phosphate (KDP) crystals were grown under the irradiation of ultraviolet light. The bulk laser damage threshold was improved to two to three times (15–20 J/cm2) compared to the case of crystals grown by conventional methods. Microbes such as germs and bacteria are frequently generated in the KDP solution with the usual growth method. The ultraviolet light reduces or eliminates organic materials such as microbes or their carcasses incorporated into the crystal, which are the cause of low damage threshold.