AgGaGeS_4晶体生长及性能研究

Growth and Properties of AgGaGeS_4 Crystals

采用竖式布里奇曼法成功生长出大尺寸30mm×80mm的AgGaGeS4单晶。X射线摇摆曲线测试结果表明该单晶结构完整。单晶元件在1.5～9.6μm波段平均吸收系数约为0.25cm-1,其中6.7～7.8μm波段小于0.02cm-1。制备的Ⅰ型相位匹配晶片元件(切角θ=43.5°,φ=0°,尺寸7mm×7mm×2.7mm),在中心波长8.0305μm基频光泵浦下,倍频输出了4.0153μm红外激光,实验测得其实际相位匹配角为42.2°。利用波长2.05μm、脉冲宽度20ns的激光光源,测得其激光抗损伤阈值为270MW/cm2。结合相图及温场分布对晶体生长过程中的关键问题进行了分析。

Large-size 30 mm×80 mm AgGaGeS4 single crystals were successfully grown by vertical Bridgman method.The X-ray rocking curves showed that single crystal quality was perfectly well.The absorption coefficient was smaller than 0.25 cm-1 on average with wavelength from 1.5 μm to 9.6 μm and the values was lower than 0.02 cm-1 in the 6.7-7.8 μm band.A crystal element （the dimension 7 mm×7 mm×2.7 mm ） was built for second harmonic generation （SHG） from the crystal boule and the cutting angles were θ=43.5°,φ=0°.Frequency doubling from 8.0305 μm to 4.0153 μm was demonstrated and the phase matching angle measured was 42.2°in the experiments.The damage threshold was 270 MW/cm2 for λ= 2.05 μm and τ=20 ns.We also analyzed some crucial problems in growth process according to phase diagram and temperature field distributions.