Glasses As Active Materials For High Average Power Solid State Lasers

Abstract

The active material is one of the crucial components of high average power solid state lasers. The maximum average power of present-day commercial solid state lasers is in the order of 1 kW. Several kW are expected to be available in the near future. In order to achieve this design objective, one has to understand which parameters of the active materials are responsible for the limitations of the maximum average power. As long as the lasers are pumped by flashlamps in a broad band, the most important limiting property is the maximum acceptable thermal stress due to temperature differences in the active solid material. Crystal-line active materials have an advantage as compared to laser glasses because of their larger coefficients of thermal conductivity and of their larger surface strength. On the other hand, active laser glasses can be produced in larger volumes and with better homogeneity than crystals. In addition, the surface strength of laser glasses can be increased by ion excange. In the paper, several possibilities especially with laser glasses will be discussed how the thermal load of the active material can be reduced in order to overcome the present limitations and to increase the maximum average power of solid state lasers.