Thermal stress on the three-sides-pumped Yb:YAG laser disk by Finite Element Method

In this paper, the thermal effects because of temperature gradient and the stress distribution on a Yb:YAG thin disk under the three-side pumping with different powers are investigated. The side surface of the disk is being pumped by three continuous working diode lasers and its underside plane is being cooled by water. The amount of distribution of temperature and stress in the disk is studied by the Finite Element Method (FEM) with the help of ANSYS software. The largest power absorbed by Yb:YAG crystal is 240 W which in this power, the temperature of active material reaches 408 K and its stress is 132 MPa. The variations of refractive index and focal length created in the thin disk are calculated by obtained data from ANSYS software and indicates that Yb:YAG disk remained isotropic and it is a suitable laser active substance.