LY12铝平面靶对1.06μm激光反射率的测量

REFLECTIVITY MEASUREMENTS FOR 1.06μm LASER PULSES INTERACTING WITH LY12 AIUMINIUM TARGETS

采用激光反射率多路测试仪,测量了LY12铝平面靶对1.06μm激光的反射率和反射激光强度的空间分布。在大气、室温环境下,靶表面粗糙度为1.6～3.2μm,激光功率密度由16.8kW/cm^2上升至60.8kW/cm^2时,长脉冲激光反射率由0.90降至0.80。激光功率密度为283MW/cm^2时的短脉冲激光反射率为0.78。而激光反射率和反射激光强度空间分布与靶的温度场、后退的烧蚀面光学特性及蒸汽羽对激光的吸收性质有关。

Reflectivities and spatial distributions of reflected light was measured with a multi ?chanell apparatus for 1.06μm laser pulses interacting with LY12 aluminum targets in 1 atm air. As the laser power density changed from 1.68×l04 to 6.08 × 104W/cm2 with target surface roughness 1.6~3.2μm, the reflectivity reduced from 0.90 to 0.8 for long pulses. For 2.83 x 108 W/cm2 short pulses, its reflectivity was 0.78. The experiments indicated that reflectivity and thd spatial dlistribution of the reflected light was dependent on the temperature field of the targets, optical property of ablated surface and the mechanism of laser energy absorption by vapor plume.