Numerical approach to temperature and thermal stress in direct-liquid-cooled Nd:YAG thin disk laser medium

Abstract

A Nd:YAG thin disk is end-pumped by two high power laser diodes and the fluid flows in a narrow channel to cool it directly. The forced convection occurs between the fluid and disk. A system is designed to measure the convective heat transfer coefficient with different flow rate. With the measured coefficient, the temperature and thermal stress in the disk are numerically analyzed. The maximum permissible thermal load is calculated, which increases with the increasing flow rate. Furthermore, the optical path different distribution is numerically calculated by considering of the thermo-optical effect, and thermal expansion at the maximum permissible thermal load. These results are useful for design of a directliquid-cooled Nd:YAG thin disk laser.