Study On The Longitudinal Gain Distribution In Ld End-Pumped Nd:YAG Crystal

There are a variety of factors that influence the output laser performance in the laser diode end-pumped solid-state laser system. One of the important factors is the spatial distribution of the pump beam. In this paper, it’s systematically researched that the influence of pump beam spatial distribution over the mode matching of laser, so is the brief analysis of heat distribution in the crystal under that case.In this paper, Monte Carlo ray tracing method is used to establish a mathematical model of differential Gaussian beam. By using Matlab software programming, the simulation of the longitudinal gain distribution inside the crystal of laser diode end-pumped solid state is generated. The characteristics of Gaussian beam can be fully considered by using new program algorithm, and the Gaussian beam transmission inside the crystal can be simulated more accurately. By integral calculating the energy values absorbed inside the fundamental mode volume of crystal, one could obtain the best focal position in the crystal. It’s shown that the result by using energy integration method is consistent with that by using mode matching equation method, the best focal position could also be proved by the brief analysis of the thermal distribution. Through the establishment of mathematical model, one could take further analysis of the influence of the pump system parameters over the best focal position, as well as over the laser output. This paper would provide an active reference to the designing of laser pump system.