激光脉宽和功率密度对烧蚀性能影响研究

微纳卫星的飞速发展对微推力器的性能提出了更高的的要求。激光推进微推力器因其比冲高、推力控制精确、能耗低等特点，为微纳卫星提供了一种性能优异的微推力器选择方案。文中在透射式烧蚀模式下，研究了半导体激光器的激光功率密度和脉宽对激光烧蚀性能的影响。结果表明，在工质厚度为200 μm的工况下，随着激光功率密度的增加，单脉冲冲量和比冲都逐渐增大，而冲量耦合系数和烧蚀效率都存在一个最优值。随着激光脉宽的增加，单脉冲冲量逐渐增加，比冲呈现出先增大后减小的趋势，在250 μs时，比冲达到最大值，约为221.8 s；冲量耦合系数和烧蚀效率都随着脉宽的增大而减小；脉宽超过一定的临界值时，会对激光烧蚀工质的靶坑产生不良影响，使得激光能量和工质严重浪费。激光参数的优化对于激光推进微推力器的工程化应用提供了参考。

Research on the influence of laser pulse width and power density on ablation performance

With the rapid development of micro-nano satellites, the performance of micro-thrusters is required to be higher. Because of its high specific impulse, precise thrust control and low energy consumption, the laser-propelled micro-thruster provides an excellent micro-thruster choice scheme for micro-nano satellite. In this paper, the influence of power density and pulse width of semiconductor laser on the performance of laser propulsion was studied in transmission ablation mode. The results show that when the thickness of the working medium layer is 200 μm, with the increase of the laser power density, the single pulse impulse and specific impulse gradually increase. And there is an optimal power density value to the impulse coupling coefficient and ablation efficiency. As the pulse width of the laser increases, the impulse of the single pulse gradually increases, and the specific impulse first increases and then decreases. At 250 μs, the specific impulse reaches its maximum value, which is about 221.8 s. The impulse coupling coefficient and ablation efficiency decrease with the increase of pulse width. When the pulse width exceeds a certain critical value, it will have a bad effect on the target pit of the laser ablation working medium, resulting in a serious waste of laser energy and working medium. The optimizing of laser parameters provides a reference for the engineering application of laser propelled micro-thruster.