Simulation Design Of LDA Side-pumped Polygonal Nd:YAG Thin-disk Amplifier

This paper reports a laser diode array(LDA)side-zigzag-pumped polygon Nd:YAG thin-disk laser amplifier.Design a reasonable coupling system and in-depth numerical simulation of the pump light absorption in the Nd:YAG polygonal gain medium by 3D ray tracing method.Study of the effects about the Nd³⁺doping concentration and the gain medium side angle on the uniformity of pump light absorption distribution with 1.5mm thickness and 16mm end-face media size.When the side angle is 35°to 65°and the Nd³⁺doping concentration is 0.20at.%to 0.30at.%,the pump light absorbed in the medium has a uniform flat-top distribution and the pump light distribution uniformity is better than 0.1,and verified by the experimental measurement of the fluorescence distribution of the medium.The research shows that it is easy to achieve uniform distribution of the pump light in the medium by using the side-zigzag-pumped method.Secondly,the relationship between the small signal gain coefficient and the pump light energy absorbed by the medium is obtained through theory and experiment.Finally,the thermal effect of the medium is simulated and analyzed with the multi-physics coupling software.This paper provides an important reference for the optimal design and experimental research of LDA side-zigzag-pumped polygon thin-disk laser.