This paper investigates the monolithic edge-cladding process for the elliptical disk of N31-type Nd-doped phosphate laser glass, which will be utilized under liquid cooling conditions for high-power laser systems. The thermal stress, interface bubbles and residual reflectivity, which are due to high-temperature casting and bonding during the monolithic edge-cladding process, are simulated and determined. The applied mould is optimized to a rectangular cavity mould, and the casting temperature is optimized to 1000°C. The resulting lower bubble density makes the mean residual reflectivity as low as 6.75 × 10^-5, which is enough to suppress the amplified spontaneous emission generated in the Nd-glass disk, and the resulting maximum optical retardation is converged to 10.2–13.3 nm/cm, which is a favourable base for fine annealing to achieve the stress specification of less than or equal to 5 nm/cm. After fine annealing at the optimized 520°C, the maximum optical retardation is as low as 4.8 nm/cm, and the minimum transmitted wavefront peak-to-valley value is 0.222 wavelength (632.8 nm). An N31 elliptical disk with the size of 194 mm × 102 mm × 40 mm can be successfully cladded by the optimized monolithic edge-cladding process, whose edge-cladded disk with the size of 200 mm × 108 mm × 40 mm can achieve laser gain one-third higher than that of an N21-type disk of the same size.

稀土的发光和激光性能都是由其4f电子在不同能级之间的跃迁产生的。由于稀土离子的独特性能，使得稀土掺杂光功能玻璃无论作为主动还是被动元器件，均在高功率激光系统发挥着重要作用。掺钕磷酸盐激光玻璃和掺铒磷酸盐激光玻璃，具有高稀土离子掺杂浓度、大尺寸和高均匀制备特性，分别是1 um和1.5 um人眼安全波段重频-大能量激光器的重要增益介质材料；光致热折变玻璃及体光栅器件，可实现波长选择和模式选择功能，具有衍射效率高、热稳定性好和抗损伤阈值高等特点，是高功率激光系统中重要的、多功能元器件。文中主要介绍了上海光机所最近几年在掺钕磷酸盐激光玻璃，掺铒磷酸盐激光玻璃以及掺铈的光致热折变玻璃及体光栅器件的研究进展。

A novel four light ray path test method for measuring residual reflectance has been presented. Residual reflectance spatial distribution at a cladding interface was measured using the technique. Residual reflectance could be on the order of 10^?5 by matching the refractive index of Nd:glass, polymer, and cladding glass and eliminating defects in the adhesive layer. Residual reflection spatial distribution appears to be similar to Newton rings due to the edge surface flatness. The relationship between the residual reflectance and the edge surface flatness was discussed, and the results revealed that the edge surface flatness is very important during the cladding process.

Large aperture Nd:phosphate laser glass is a key optical element for an inertial confinement fusion (ICF) facility. N31, one type of neodymium doped phosphate glasses, was developed for high peak power laser facility applications in China. The composition and main properties of N31 glass are given, together with those of LHG-8, LG-770, and KGSS- 0180 Nd:phosphate laser glasses, from Hoya and Schott, and from Russia. The technologies of pot melting, continuous melting, and edge cladding of large size N31 phosphate laser glass are briefly described. The small signal gain profiles of N31 glass slabs from both pot melting and continuous melting at various values of the pumping energy of the xenon lamp are presented. N31 glass is characterized by a stimulated emission cross section of 3:8  10??20 cm2 at 1053 nm, an absorption coefficient of 0.10–0.15% cm??1 at laser wavelength, small residual stress around the interface between the cladding glass and the laser glass, optical homogeneity of 2  10??6 in a 400 mm aperture, and laser damage threshold larger than 42 J/cm2 for a 3 ns pulse width at 1064 nm wavelength.