天文望远镜增强银保偏反射镜的设计与制备OA

To meet the requirements for high-performance mirrors in the optical system of laser communication terminal,it is essential to ensure that the film achieves a high reflectivity of>99%at the target wavelengths of 808 nm and 1550 nm,while also modulating the phase of polarized light,so that the phase difference between s-and p-polarized light remains below 1°.This study aims to overcome the limitations of insufficient phase accuracy in traditional metallic mirrors,develop an enhanced silver-based polarization-maintaining mirror,and verify its reliability in space environments.The designed enhanced silver reflective film for the astronomical telescope plays a crucial role in the optical system development of laser communication terminal. Using the equivalent-layer design theory,a film structure of"metal+aperiodic multilayer dielectric film"was adopted,selecting silver(Ag)as the metal and TiO2 and SiO2 as the dielectric film layer materials.The initial structure was sub|(2TiO2 2SiO2)6(TiO2 SiO2)6Ag|air,and multi-objective optimization was performed with reflectivity and phase difference as the targets.The enhanced silver reflective film samples were prepared using electron-beam evaporation ion-assisted deposition technology,combined with a quartz crystal oscillator and a high-precision optical film thickness monitoring system to control film thickness and deposition rate.After preparation,the samples were subjected to immersion,temperature cycling,adhesion,and damp-heat reliability tests. The measured reflectance at 808 nm and 1550 nm was≥97.5%for s-polarized light and≥98.95%for p-polarized light(Fig.7,Fig.8).The phase differences in the two bands measured by ellipsometry were 0.65°±0.085° and 0.70°±0.08°,respectively(Fig.10).All reliability tests were passed(Table 3).The reflectance decreased by approximately 2%compared to the theoretical value,and the phase difference increased by approximately 0.3°,mainly due to scattering caused by the microscopic roughness of the film layers,slightly lower density of TiO2/SiO2 layers,and cumulative errors in film thickness. For the first time,a silver mirror has achieved dual-band high reflectance while maintaining polarization phase control of less than 1°.A film structure of metal plus multilayer dielectric film is used,which is prepared using electron-beam evaporation ion-assisted deposition technology.It plays a key role in the development of the optical system for laser communication terminal.The enhanced silver reflective film undergoes a series of environmental tests,verifying its reliability.The specific processes involved in the design and preparation of this reflective film also provide valuable reference for research on polarization-phase reflective films at other wavelength bands.