Optical properties of rapidly grown KDP crystal improved by thermal conditioning

Abstract The medium-size crystal (64 × 63 × 43mm) of potassium dihydrogen phosphate (KDP) was grown for one day from the 8 mm cubic seed crystal with a growth rate over 30 mm/day. The spectral transmittance, second-harmonic generation (SHG) property and laser damage threshold of the rapidly grown crystals were measured. The comparison with those of conventionally grown KDP crystal (2 mm/day) showed the prismatic sector included more impurities resulting in UV absorption. No difference was detected between the SHG properties. The lower laser damage threshold of the rapidly grown crystal was improved by a thermal conditioning to be 17 J/cm 2 of 1 ns pulse at 1 mm wavelength.