Thermal Management With Host Flow Of High-Average-Power Inorganic Liquid Laser

The liquid laser of inorganic aprotic solvents incorporated with rare earths has drawn much attention. The low operation cost,easily preparing laser solution and the more compact system structure make the liquid laser attractive for many applications. The most important advantage is that the flowing of gain media can make thermal management easy and efficient. Therefore,developing new type high–average-power laser focuses on the inorganic liquid laser. With the output power increasing,thermo-optic effects impose the main restrict on liquid gain media to achieve high beam quality under high-average-power operation.Effective thermal management is major techniques to eliminate thermo-optic effects in gain media. Compared to using thermal conduction or heat-capacity methods , the thermal management efficiency that the flowing of inorganic liquid displaces gain media in pump region rapidly is higher. In this paper, the development progress of inorganic liquid laser has been reviewed primarily. Methods of eliminating thermo-optic effects and importance of gain mediaflowing in liquid laser have been clarified. Whereafter the laser system structure for 100kW output power has been discussed. And structure for flowing uniformly in pump region has been analyzed. The design of pump and flow structure has been given and the flow field has been simulated with fluid analysis software FLUENT. The effect of achieving uniform flow usingdesigned structure has been validated. Finally, the temperature distribution has been computed. Main reasons for temperature rising have been analyzed from energy equation in flowing liquid, effects and problems of eliminate thermo-optic effects using gain media flow have been discussed.For the study of this paper, it is indicated that the thermal management using gain media flow can eliminate thermo-optic effects cumulation between pulses. Temperature rising has been controlled within a certain range. Laser system can work continuously with a long time. However thermal management using gain media flow can not restrain thermal deposition in pump pulse duration under long-pulse operate conditions. The beam quality of inorganic liquid laser is incapable to be optimized.