Study On Effects Of Gain Distribution And Themerl Distribution Of Highly Efficient Solid-state Laser

One of the fundamental characteristics of a laser that is different from the ordinary light source is that it has a good beam quality and can transmit in space at a divergence angle close to the diffraction limit.The better the beam quality of the laser is,the better the application effect is.Only if the laser has a good beam quality,can the laser energy still be concentrated within a small range after long-distance transmission.It is critical no matter for the detection of remote targets or the attack on the target.At the same time,for military application,taking into consideration the needs of mobile carriers,the laser not only needs high beam quality of the laser,but also needs to have as low energy consumption as possible,which means that the laser needs to have high energy conversion efficiency.This paper aims to solve the key technical problems that emerged in order to achieve high beam quality and high energy conversion efficiency in solid lasers with high power and high efficiency,so as to find a technical route with universal practicability.The paper introduces the development process of laser diode-pumped solid-state lasers and the main development status and bottlenecks at the present stage.The main research problems are proposed,and the development status and application background of laser diode-pumped solid-state lasers are introduced.And we take Nd:YAG crystal as an example and researches the theoretical model of the thermal effect of the crystal.Through the stimulation of the crystal temperature distribution and phase difference distribution,this chapter researches the impact of thermal effect on temperature distribution and phase difference distribution and calculates the loss of laser mode caused by thermal effect,.Besides,the influence of thermal effect on loss is studied.Then we take the side-pumped DPL as the research object,and researche the steady-state thermal effect of the side-pumped laser by studying the distribution of heat source and the heat dissipation condition of the laser medium.This simulation calculation uses a kind of surface heat source adaptive adjusting algorithm rather than the traditional finite element method.The distribution of pump light in one-way pump and three-way pump is calculated respectively.The spatial distribution of three-phase pump light in the crystal is simulated and the influence of crystal radius and crystal doping concentration on pump light distribution is obtained.Besides,the temperature distribution of one-way pump is studied,and the rules of the influence of pump light radius,pump light power and pump source distance on temperature field distribution are obtained respectively.At the same time,the impact of three-way pump and five-way pump on the temperature distribution of operating substanceis studied.We also focus on the influence of the gain distribution on the conversion efficiency of the three-way side pump and the five-way side pump without considering the thermal effect.Respectively,the paper calculates the efficiency loss of three-way side pump and five-way side pump caused by the gain distribution.The influence of the length of the laser diode array and the number of the pump direction on the output beam quality is obtained.Meanwhile,the influence of the doping concentration of operating substance on absorption efficiency is obtained.