希土類ペンタフォスフェイトの結晶成長

The crystal growth conditions and some opticaI properties for neodymium pentaPhosphate crystals (NdP₅O₁₄) have been studied. The size, shape and quality of crystals are much affected by crystal growth conditions. The optically high quality crystals are obtained from phosphoric acid solution of the weight concentration ratio of 40 : 1 of H₃PO₄ and Nd₂O₃ at the temperature of about 500℃ in saturated water-vapour pressure. The crystals obtained are 2～4 mm in size, and 0.4～l mm in thikness, and their shapes are hexagonal plates. The absorption coefficient is intensitive to crystal growth cnditions, being nearly 13.l cm⁻¹ at 514.5 nm　excitation of Ar laser. The emission peaks are 0.89 μm and l.05 μm with linewidth of adout 10 nm. The lifetime is slightly affected by crystal growth temperature. The lifetime measured are 120 μs and 100 μs respectively, for growth temperature of 550℃ and 500℃.