Simulation and analysis of OPD in a CW dual-slab Nd:YAG high-power side-pumped laser

Abstract

Abstract High-power solid-state slab lasers face limitations in their performance due to thermal effects such as end effects, thermal gradients, and stress gradients, which cause optical path difference (OPD). To simulate thermal distribution and OPD in a diode-pumped high-power Nd:YAG slab laser, a combination of ray tracing and finite element method (FEM)was used. Furthermore, to calculate the OPD induced by the stress gradients, a formula was developed. In this geometry (inlet coolant velocity \({u}_{in}=0.3\frac{m}{s}\)), the peak to valley (P-V) value of overall OPD is \(10.2 \mu m\), and the thermal gradient in the coolant has the most impact on it. The simulation results indicated that changing the inlet coolant velocity from \(0.2\) to \(0.6\frac{m}{s}\) resulted in a decrease of OPD's P-V from \(13.1 \mu m\) to \(6.71 \mu m\).