Research On Solid Microspheres Laser And Its Thermal Management

In recent years, the laser which have the high-average power or high energy output is widely used in all areas of society. So those laser is one of the hot spots of the current research in the field of laser technology. In pursuit of high-average power output, the thermal effect of the solid-state gain medium is particularly prominent in the laser system. In the paper, a new structure laser is proposed in order to solve the thermal effect of the solid-state lasers, in which solid particles (the neodymium glass microspheres) are arranged regularly. Refractive index matching fluid do circulation flow through the gain region. So the laser both inherites the good laser performance of the solid-state laser materials and has the flow ability of the liquid laser, which is currently the most efficient cooling mode.This paper first discusses the development course of high-energy laser system and the latest scientific research at home and abroad. Then the output energy, threshold energy and Relevant factors affecting the laser output are derived based on the rate equation of the four-level laser system. The pumped coupling system of the laser is designed by ZEMAX software and the temperature distribution after the pumping is research based on experimental parameters. For the coupled thermal effects between liquid and solid happened in fluid state laser pumped,thermal-flow-solid coupling model is established by fluent6.3.26to analyze changes in the relationship between cooling times and model size, fluid velocity. The simulation analysis which involves in thermal, fluid dynamics and laser optics is researched systematically.On this basis, the Nd glass microspheres and the different refractive index matching fluid are Prepared. Then the refractive index of the glass microspheres, absorption spectra, fluorescence spectra and the temperature coefficient of refractive index matching fluid are tested. The solvent resistance and light stability of the respective samples were compared and analyzed to verify the feasibility of this configuration used for high power laser system.The circulation system can monitor the pressure and temperature of the fluid. The experimental optical path of the slab laser and neodymium glass microspheres laser are set up, and the laser achieve to output energy successfully under current cycling conditions. The coupling efficiency, the slope efficiency, laser spot,output energy and pulse width are tested in the experiment. The laser can work stably under the continuous pump, which means that the laser has good thermal stability.Experimental data show that the maximum pulse energy is 114mJ and peak power can up to1.14KW. At the same time, some problems are found during the experiment. For example, the output energy of thelaser drop obviously when the repetition frequency is increasing. The research about refractive index matching fluid cooled the Nd glass microsphere laser provides a new way to solve the problem of thermal management for solid-state lasers and plays a positive role in promoting the development of the laser.