Design And Fabrication Of Polarization- And Phase-Modulated Mirror

In this study, the equivalent film theory is used to develop a polarization- and phase-modulated mirror with target wavelengths of 780, 810, and 850 nm and an incidence angle of 45 degrees. Apart from achieving polarization and phase modulation, the obtained mirror can ensure the high reflectivity of the thin films. A metallic material (Ag) and two dielectric thin film materials (such as Ta2O3 and SiO2) arc selected as the film materials to obtain high reflectance over a wide waveband. The mirror film system is fabricated on an optical glass substrate (JGS-1) using the electron beam evaporation, thermal evaporation, and quartz crystal oscillation monitoring technologies. The measured spectra of the mirror film system denote that the average reflectance is greater than 959 in the wavelength range of 500-1600 nm and the extinction ratios at the target wavelengths exceed 3000:1, 5000:1, and 7000:1. Thus, the proposed mirror satisfies the reliability requirement associated with space-to-ground quantum communication.