摘要：设计并制备了一种在45°斜入射条件下使用的金属Ag消偏振反射镜，这种反射镜可以实现对目标波长810 nm和850 nm光线的反射，并保持线偏光的偏振方向和偏振消光比。为了消除s和p两偏振分量的分离，在金属Ag膜层上方添加了介质多层膜结构，并利用软件对膜系的结构进行了优化，设计结果的能量和相位特性满足目标需求。介质多层膜选用TiO2和SiO2分别作为高、低折射率材料，薄膜的制备采用了离子束辅助沉积工艺，并利用石英晶体振荡监控膜层厚度。得到了消光比达到10 000∶1以上的样品，实现了光学薄膜器件对能量和相位的控制，满足了偏振编码空间光通信试验的需求。

　　关键词：光学薄膜； 消偏振反射镜； 相位控制； 偏振编码

　　中图分类号： O 484文献标识码： Adoi： 10.3969/j.issn.10055630.2012.06.018

　　Introduction

　　Polarization coding is a strategy simple and easy to realize in photonic communication process.In the traditional optical fiber communications，birefringence effect[1] seriously interferes with the polarization states and limits the application of polarization coding.With the rapid development of free space photonic communication[2]，the impact of fiber on the polarization states information is avoided，the advantages of polarization coding are increasingly apparent.According to the scattering and absorption properties of atmospheric particles，with the aim of reducing the attenuation of the optical signal in space during transmission，people usually select the 810 nm，850 nm，1.06 μm and 1.55 μm near atmospheric window as free space photonic communication channel[3].The 810 nm and 850 nm wavelength channels are especially more developed because the signal sources are easier to be achieved.The information carrier of polarization coding is the different polarization states of lights，and therefore demanding higher requirements for the optical thin film devices in the optical system.Based on the traditional spectrum control，the control of phase separation between polarization components and energy polarization effects of optical system must be considered.

　　At oblique incidence，the polarization effects of optical multilayer film are difficult to be avoided.In usual optical remote sensing applications，sensible polarization effects will engender the distortion of energy information.And the polarization characteristic of optical signals also contains some available information.For these reasons，with the development of remote sensing technology，more and more applications require the polarization control of optical thin films.Since Baumeister[4] designed first polarization control film in 1961，many researches have been carried out in polarization effect of optic thin films and polarization control film devices；Thelen[5] designed depolarization dichroic filter at oblique incidence for the first time in 1980；John S Seeley[6] designed depolarization dichroic filter with symmetric periodic thinfilm structure.