Study On Thermal Effects Of Diode Pumped Solid-State Heat Capacity Laser

As one of technology paths to solve heat management in high average power solid state laser, the operation mode of solid state heat capacity laser (SSHCL) can reduce the thermal effects and the optical path distortion in medium, reduce the pump power limit because of medium fracture limit, improve the output power and the beam quality of laser, and has the scalable ability to more than 100 kW output laser power. So SSHCL has been one of the optimal candidates of the next high average power solid state laser generation and has been a hot spot in the international laser field.Because of great military application background, the open research reports overseas focus mainly on analysis of theory, technology scheme, stage experiment progress and so on, but the pivotal technology is strictly confidential. So it is very important to develop and improve the operation mode concept of SSHCL, essential theory, and technology scheme, and break through the difficulties in experiment of engineering. Based on such, the theoretical and experimental research of laser diode array symmetrically side-pumped SSHCL are made in this paper:A pump structure of high power laser diode array symmetrically side-pumped medium is designed, and the three-dimensional uneven pump distribution and thermal-stress distribution of medium are simulated and analyzed; The experiment setups of high power laser diode array symmetrically side-pumped Nd:GGG were built according to the designed pump structure and the simulation conditions. The experimental research and theoretical analysis were made in detail, and the experimental results are accordant with the analysis results and simulation results. The investigation is the domestic highest level.Firstly, the design principle and key points of SSHCL are discussed and analyzed in detail from the medium, the pump source, the resonator and so on.Secondly, a laser diode array symmetrically side-pumped single medium structure of SSHCL is designed and analyzed, and the three-dimensional pump distribution and the thermal-stress distribution in medium are simulated and analyzed by the ray tracing method and the finite element method. A laser diode pump mode and the heat source mode according with the practical situation are built with homogeneously considering the divergence characteristic of fast axis and slow axis and the three-dimensional uneven heat deposit distribution in medium. Compared with the early open research reports on pump distribution and thermal-stress distribution in medium, there are no relative reports on simulation of homogeneously considering the pump mode of laser diode and the three-dimensional uneven heat source distribution in medium in this paper. The conclusion of simulation and analysis can provide theoretical basis of knowing the three-dimensional uneven thermal-stress distribution in medium and deciding_the safe operation range of SSHCL.In this paper, the effect of the SSHCL factor, the temperature factor of medium and the time factor of laser burst on output characteristic of SSHCL is developed and analyzed, and the conclusion of simulation and analysis can provide theoretical basis on predicting the performance and deciding the operation parameter of SSHCL.Finally, the four high power laser diode arrays symmetrically side-pumped Nd: GGG setups were built, and the relative experimental research and analysis were made. The temperature distribution and pump distribution in medium of experiment and simulation are according with each other, which directly verifies the correctness of structure design concept and the method, mode, and results of simulation. The 1.49 kW output laser average power was. obtained with 24.1% optical-optical efficiency by single chip Nd:GGG SSHCL setup; the 5.27 kW output laser average power was obtained with 23.3% optical-optical efficiency by three chips of Nd:GGG Series SSHCL setup; and the 8.77 kW output laser average power was obtained with 20.2% optical-optical efficiency by five chips of Nd:GGG Series SSHCL setup. After the investigation on the open reports, the investigation is the domestic highest level. The experimental results and conclusion can provide experimental basis of the development and optimal design of laser diode pumped SSHCL.