Study of conductively cooling technology for spaceborne high energy all-solid-state 2μm lasers

With the wide application of spaceborne lidar, 2 μm laser with high repetition rate and high energy has become an important candidate for coherent detection lidar. Conductively cooling is recognized as the critical technology for high energy, 2 μm lasers. The structure and thermal design of a totally conductively cooled, diode side-pumped, 2 μm laser amplifier is introduced in the paper. The amplifier consists of a 20-mm-long Tm: Ho: YLF crystal pumped by 2-banks of 3-radially arranged diode lasers (LD). Through the research and analysis of the structure and thermal coupling of the amplifier head, the conductively cooling scheme satisfying the need of the application in the space environment is obtained. The peak power consumption of LD is 200 W and the average heat consumption is 23.76 W at 10 Hz. When the coolant temperature is 17°C, the stable temperature of the crystal center is about 30°C, which achieves the result of 2.6 times of laser energy amplification. The experimental data matches the result very well.