大口径高性能激光钕玻璃研究进展

 在概述国内外高功率激光钕玻璃的发展及其主要性质的基础上,重点论述了上海光学精密机械研究所在大口径N31高功率激光钕玻璃半连续熔炼工艺、连续熔炼工艺、包边工艺等方面的研究进展。报道了半连续熔炼工艺制备的不同Nd₂O₃浓度N31钕玻璃的光吸收损耗和荧光寿命及小信号增益系数,并给出了这些钕玻璃坯片小信号增益系数的波动范围。通过对半连续熔炼和连续熔炼工艺制备的N31激光钕玻璃主要性能的比较,证明连续熔炼工艺制备的N31钕玻璃的主要性能指标与半连续熔炼的性能相当。对于400 mm大口径N31钕玻璃坯片的包边进行了模拟考核,结果表明,采用现有包边工艺的钕玻璃可以承受1 000次高功率氙灯辐射。     

Experimental investigation on laser-induced surface damage threshold of Nd-doped phosphate glass

Nd-doped phosphate glass is the dominant amplifier material used in solid state high average power laser systems.Surface imperfection and subsurface damage(SSD)of the glass,resulting from the optical fabrica-tion process,limit the increment of laser system energy output.Thus,it is important to enhance the surface damage threshold of Nd-doped phosphate glass surface.The influence of abrasive size,polishing powder,grinding mode,and chemical treatment on the laser-induced damage threshold(LIDT)of Nd-doped phos-phate glass surface is investigated.Results show that the LIDT is affected little by different polishing powders and grinding modes.The LIDT correlates with the abrasive size,which produced different depths of SSD.A suitable acid etching treatment can remove the imperfection and the SSD for improving the LIDT of Nd-doped phosphate glass surface.The combination of several effective techniques and methods,which are low-cost and practical,should be useful to enhance the LIDT of Nd-doped phosphate glass surface.     

后处理对离子交换磷酸盐玻璃平面光波导的影响

研究了退火和二次离子交换对Er3+/Yb3+共掺的磷酸盐玻璃平面光波导传输特性的影响。在退火过程中，由于热效应和波导层Ag+离子的浓度差使得Ag+离子重新分布；随着退火时间的延长和温度的升高，光波导模式数目逐渐增加，波导层深度加深，且波导表面折射率与玻璃基质折射率差减小，退火扩散深度与退火时间的平方根成正比。电子探针结果显示在二次离子交换后形成了掩埋式的光波导，Ag+离子浓度接近二次方分布，而掩埋式的光波导有助于降低光波导的传输损耗。     

Planar waveguides formed in a new chemically stable Er~(3+)/Yb~(3+) co-doped phosphate glass

A new Er3+/Yb3+ co-doped phosphate glass has been prepared, which exhibits good chemical durability and spectral properties. Planar graded index waveguides have been fabricated in the glass by Ag+-Na+ ion exchange in a mixed melt of silver nitrate and potassium nitrate. Ion exchange is carried out by varying the process parameters such as temperature, diffusion time, and molten salt compositions. The diffusion parameters, diffusion coefficients, and activation energy are determined by the guidelines of fabricated waveguides, which are determined by the input prism coupling technique.