基于复合光栅镜的角向偏振光产生研究

摘要

为了得到角向偏振光输出，采用严格耦合波分析方法，设计了一种复合光栅镜。先通过对Ge光栅的伪博世工艺刻蚀特性的研究，得到了高深宽比的无定型Ge光栅。然后在栅槽底部引入了随机分布的Ge纳米针，在该光栅上依次镀金膜和介质保护膜，得到介质－金属复合光栅镜。最后将该复合光栅镜用作轴快流CO2激光器谐振腔尾镜，得550W角向偏振光输出。结果表明，纳米柱及金栅脊的引入使得该复合光栅镜具有很高的偏振选择性。%To achieve azimuthally polarized beam , hybrid grating mirror was designed based on rigorous coupled wave analysis method . At first, amorphous Ge grating with high depth-to-width ratio was obtained by studying the etching characteristics of pseudo Bosch process on Ge grating .And then, dielectric-metal hybrid grating mirror was obtained after the randomly distributed Ge nanoneedle was introduced at the bottom of gate groove , and gold film and dielectric protective film were coated in turn.Finally, 550W azimuthally polarized beam was generated when hybrid grating mirror was used as the rear mirror of a fast axial flow CO2 laser.The results show that hybrid grating mirror has high polarization selectivity because of the introduction of nano-pillars as well as gold ridge .