激光反射镜的散射损耗分析与设计

在激光反射镜的光学损耗里,表面散射损耗(SSL)对高精密的激光仪器性能和实验影响尤甚,有时是致命的。本文根据光学膜系散射和吸收理论分析了反射镜膜系的SSL与吸收损耗,反射率以及膜系特点、材料之间的关系和矛盾,利用光场在膜系中的合理分配方法,设计了一种旨在减小SSL的新型激光反射镜膜系。设计结果表明,在相同设计下,用La₂O₅/SiO₂和ZnS/MgF₂构成的新的组合膜系的激光反射镜与通常的ZnS/MgF₂膜系的激光反射镜比较,SSL的减小达到了设计要求,而且使激光反射镜中另一主要损耗——体积损耗(VL)减小更多,其它的一些性能也得到了改善。采用此新型膜系可望做出总损耗小于0.1%,反射率在99.9%以上的低表面散射损耗的高质量激光反射镜,它对激光技术的发展与应用有着重要的意义。

ANALYSIS OF SCATTERING LOSS OF LASER REFLECTOR AND DESIGN

The surface scattering loss (SSL) in the optical loss of laser reflectors is the main, so metimes fatal influence on the performance and test of high-grade precision and advance instruments. In this paper the relation and contradiction among (SSL), (VL), R and properties of film material to use and charactors of multiplayer film structures is analysed on the base of the absorbing and scattering theroy of multiplayer dielectric films, and new type of multiplayer film structure for laser reflectors specially will be designed in order to reduce the (SSL) with the way of distributing rationally electric field coatings. To compare the new combinited structure reflector of Ta2O5/SiO2 and ZnS/MgF2with the normal ZnS/ MgF2, the new design indicates that (1) the reducation of (SSL) design requrement, ( 2 ) (VL) which is another main loss of the reflector is more reduced than (SSL), (3) the improvements ot other properties of reflector are abtained. If the new design adopted tnere will be a expection to produce small (SSL) excellent laser reflctors with a loss less than 0.1 % and a reflectance of above 99.9%, which is of important to the development and application of laser technique.