3D Dynamic Opto-Mechanical Modeling of Diode-Pumped Trapezoid Yb:YAG/YAG Thin Disk Laser

Abstract: In this master thesis, we present a 3D modelling of thermal lensing effect in an edge-pumped trapezoid Yb:YAG/YAG thin disk laser. At first, a Monte-Carlo ray tracing method and finite element analysis (FEA) is used to calculate the absorbed pump power from our sides in such a way, that the pump light are totally trapped inside the crystal after total reflections. To study this configuration we performed a detailed simulation of our delivery system in our laser simulation code software ASLD. Secondly, we optimized the absorption efficiency of our laser which is obtained 66.7% due to the optimum Yb:YAG dopant of 10% and efficient thickness of 0.2 mm. Then, using the result of absorbed pump light distribution as a heat source for the crystal to compute the temperature distribution inside the crystal and perform the consequences of opto-mechanical properties including Von Mises stress and deformation components distribution inside the crystal via Finite Element Analysis (FEA). Furthermore, the thermal lens power is considered in our modelling as an important consequence of opto-mechanical effect which is compared in different output powers. Finally, we applied the Dynamic Multimode Analysis (DMA) method to solve the rate equation and calculate the output powers respect to different length of cavities and different output coupler curvatures respect to the dealing beam quality in multimode operation.