Modeling and resolving calculation of thermal effect in face-pumped high power heat capacity disk laser

Abstract

The study of thermal effect plays an important role in the research and application of high power heat capacity laser. FEM has been used to seek the numerical solution of heat conduction equation in the past study of laser thermal effect, but the method can't describe the infection of laser material characteristic and pumping laser on the temperature distributing and thermal stress distributing. And it is difficult to analyze the thermal lens effect, thermal birefringence effect and their influences on the laser beam quality. The 3 dimensions heat conduction model under the cylindrical coordinate is set up on the base of pumped structure of face-pumped disk laser. And the precise solution of transient temperature field distribution is got through resolving the 3 dimensions heat conduction equation using integral-transform method. On the base of this, the thermal stress field transient distribution is worked out. Using a Φ50mm×18mm Nd:GGG disk laser as an example, the temperature distributing and thermal stress distributing under the heat capacity model is calculated. The result and the numerical solution using FEM are a good match, and the theory analyzing result is in accordance with the relative experiment result, so the thermal effect modeling and the resolving method are proved to be correct. The research establishes the base of the further theoretical analysis of thermal effect influence on the laser beam quality.