具有高激光损伤阈值的光栅分光薄膜
Surface-reliefed Gratings Film With High Laser Damage Thresholds
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摘要: 为惯性约束聚变 (ICF)实验中利用光栅分光特性间接探测激光功率研究, 制备具有高激光损伤阈值的光栅分光ZrO2 薄膜。采用水热法制备纳米ZrO2 溶胶, 在 80~ 10 0℃下, 以 2 0m /min速度涂敷制备出厚 1~ 2 μm、折射率为 1 5 7~ 1 70、表面粗糙度 2 3nm、激光损伤阈值为 2 5~ 3 0J/cm2 (1ns, 1 0 6μm)的ZrO2 薄膜。采用Ar+ 激光器双光束干涉曝光技术制备光栅掩膜板, 光栅周期为 1~ 2 μm, 深度 70~ 10 0nm。通过电镀工艺将光栅结构转移至镍板上, 经连续模压, 最终制备出光栅分光ZrO2 薄膜。分析了光栅周期、模压深度及薄膜折射率等因素对光栅一级衍射效率的影响。制备出的光栅分光ZrO2 薄膜有望用于高功率激光测量Abstract: A kind of surface reliefed gratings ZrO 2 film with high laser damage thresholds is prepared. The ZrO 2 sol is achieved by hydro thermal method, the thin ZrO 2 film with the thickness of 1~2 μm, the refractive index of 1.57~1.70, the roughness of 2.3 nm and the laser damage thresholds of 25~30 J/cm 2(1 ns, 1.06 μm) is coated on plastic foil substrate by the speed of 20 m/min at 80~100 ℃. The master structure of the gratings is produced by the holographic optical process of two coherent beams from an argon ion laser source interfe rence. The period of gratings is 1~2 μm and the depth is 70~100 nm. The patterns on the photoresists are transferred to nickel replicas by electroplating process. Finally, the surface reliefed gratings are embossed onto the ZrO 2 coated plastic foils using the nickel replicas as stamps. The influences of the period and the depth of the grating, the incident angle and the refractive index of nano coating to diffraction efficiency are researched. Therefore, this structure provides a feasible approach to detect high power laser.