One-on-One and R-on-One Tests on KDP and DKDP Crystals with Different Orientations

By testing a substantial number of tripler and z-cut KDP and DKDP crystals, we have observed that at 355 nm, the laser induced damage threshold in the R-on-one test is higher than that in the one-on-one test. It is proved that laser conditioning is an efficient way to improve the damage resistance. The efficiency of laser conditioning becomes increasingly good with smaller ramping ffuence steps. We have also found that the damage resistance of the z-cut crystal is higher than the tripler cut, and the pinpoint number is definitely less in the z-cut crystal. The reason for these observations is discussed.