Study on K(DxH1-x)2PO4 crystals: growth habit, optical properties and their improvement by thermal-conditioning

Phosphite, which often exists in growth solutions obtained directly from commercial P2O5, was found to have significant inhibiting effects on the growth of pyramidal face of KDP crystals. K(DxH1-x)2PO4 (referred to as DKDP) crystals with different deuterium fraction x were grown and the optical performances were investigated. The absorption coefficients at 1.05 μm decreases monotonically with the increase of x. The transmission threshold shift from 1.65μm at x=0 to 2.10 μm at x=0.96. The high temperature phase transition temperature and latent heat were measured using the method of differential scanning calorimetry (DSC). Thermal conditioning experiments were carried out at 180 C and 140 C for KDP and DKDP, respectively. After conditioning, a different degree of improvement was observed in the optical homogeneity of the samples, while the laser damage threshold and light absorption coefficient showed no significant change. (orig.)