Simulation of temperature distribution in thin active laser medium disk

Abstract

In design of high average power lasers one common problem is the heat generated in the active laser medium. Heating of active medium causes undesirable changes in the parameters. Temperature gradient causes thermal stresses, which may lead to damaging of the active medium upon exceeding the threshold values. These problems can be solved by a thin disk active medium geometry: one side of the thin disk is in contact with cooler. Such composition leads to more efficient heat transfer due to the large surface area of cooler. This work discusses the problem of the heat transfer in a thin disk Nd:YAG disk medium, starting with formulation of the problem and concluding with numerical solutions: the maximum temperature of the thin disk, the cross sectional area temperature distribution dependence on thickness of the disk, absorption coefficient, incident angle and focusing of the pump beam. It will be shown that maximum temperature is attained on the surface of the disk and that focusing of pump beam results a lower increase of temperature.