OPTICAL-PROPERTIES OF RAPIDLY GROWN KDP CRYSTAL IMPROVED BY THERMAL CONDITIONING

The medium-size crystal (64 x 63 x 43 mm) of potassium dihydrogen phos phate (KDP) was grown for one day from the 8 mm cubic seed crystal wit h a growth rate over 30 mm/day. The spectral transmittance, second-har monic generation (SHG) property and laser damage threshold of the rapi dly grown crystals were measured. The comparison with those of convent ionally grown KDP crystal (2 mm/day) showed the prismatic sector inclu ded more impurities resulting in UV absorption. No difference was dete cted between the SHG properties. The lower laser damage threshold of t he rapidly grown crystal was improved by a thermal conditioning to be 17 J/cm(2) of 1 ns pulse at 1 mm wavelength.