光学 精密工程, 2016, 24 (12): 2983, 网络出版: 2017-01-23
复合型透射式脉冲压缩光栅的设计与制作
Design and fabrication of a composite transmission pulse compression grating
脉冲压缩光栅 熔石英透射光栅 衍射效率 激光损伤阈值 pulse compression grating fused silica transmission grating diffraction efficiency laser damage threshold
摘要
提出了一种用于飞秒钛宝石激光器的复合型透射式脉冲压缩光栅。该光栅由1 250 line/mm和3 300 line/mm两种光栅集成在一个熔石英基底上制成, 其工作中心波长为800 nm, 工作波段为700~900 nm。1 250 line/mm光栅用于脉冲压缩; 3 300 line/mm光栅的运用则有益于减少透射光栅的反射损失, 同时由于采用高频光栅结构代替了传统增透膜, 可有效减少光栅基底的波前形变。该复合光栅完全由熔石英材料构成, 故具有很高的损伤阈值。利用严格耦合波理论对该复合型透射光栅的微结构进行了优化设计, 结果表明: 1 250 line/mm光栅在中心波长800 nm处的-1级衍射效率可达98%; 3 300 line/mm增透光栅的透过率在700~900 nm波段可以达到99.7%以上。最后, 应用全息记录技术和离子刻蚀技术实际制备了Φ65 mm×1 mm的复合式透射脉冲压缩光栅, 实测衍射效率与理论设计相符。
Abstract
A composite transmission pulse compression grating was proposed for femto-second Ti∶sapphire lasers. The composite transmission grating with 700-900 nm bandwidth worked at a center wavelength of 800 nm was consisted of two gratings with groove densities 1 250 line/mm and 3 300 line/mm and they were integrated in a fused silica plate. The 1 250 line/mm grating was used for compressing laser pulse. The 3 300 line/mm anti-reflection grating was conductive to decreasing the reflection loss and avoiding the wave-front distortion by using a high frequency grating structure to replace the anti-reflection film on the surface of the fused silica plate. Completely being made of fused silica, the composite pulse compression grating has a high laser damage threshold. The composite transmission grating was designed based on the rigorous coupled wave theory. The optimization calculation results show that the -1st order diffraction efficiency of the 1 250 line/mm grating is up to 98% (@800 nm) and the transmission of the 3 300 lp/mm grating is up to 99.7% at 700-900 nm bandwidth. Finally, the composite transmission pulse compression grating(Φ65 mm×1 mm ) was fabricated by holographic recording and ion bean etching and its diffraction efficiency is coincident with that of the theoretical analysis.
李朝明, 陈新荣, 李林, 虞健, 吴建宏, 常增虎. 复合型透射式脉冲压缩光栅的设计与制作[J]. 光学 精密工程, 2016, 24(12): 2983. LI Chao-ming, CHEN Xin-rong, LI Lin, YU Jian, WU Jian-hong, CHANG Zeng-hu. Design and fabrication of a composite transmission pulse compression grating[J]. Optics and Precision Engineering, 2016, 24(12): 2983.