Advances In Glasses For High Average Power Laser Systems

Glass compositions containing rare earth elements such as neodymium offer many of the properties desired of the active materials in high average power laser systems. The most popular laser glasses for this application are neodymium doped phosphate compositions which have high cross sections for stimulated emission, long fluorescence lifetimes, and moderate non-linear refractive index values, while still being available in large sizes with high optical quality and with large neodymium concentrations. The predominant disadvantages of glass, in comparison to crystalline materials, are efficiency and thermo-mechanical limitations. We discuss advancements which address both of these problems as well as which offer improvements in other properties relevant to glass utilization in high average power laser systems.