平板偏振膜的角度特性研究

Investigation on the Characteristics of the Plate Polarizer

当入射光倾斜入射到平板偏振膜上时,在两种偏振光的反射带边缘处出现P偏振光高透而S偏振光高反的情况.利用F-P结构的膜系设计了偏振膜.随着入射角的增大,S光的带宽、消光比及参考波长线性增大,而膜层中电场强度的最大值和界面处的电场强度均减小,只有P偏振光的变化特性跟布儒斯特角有关.分析膜层的界面特性和膜层中的缺陷分布情况,可得偏振膜P偏振光的阈值随入射角的增大而增大.结果表明,在P光透过率可使用的范围内,入射角越大,消光比越大,场强在膜层中的分布越低,但P偏振光的透过率有所降低.

When light enters plate polarizer at a certain angle, p-polarization, high transmission, s-polarization and high reflection appear on the edge of reflective band. The polarizer is designed with stack formula of F-P structure. With the angle of incidence increasing, the band-width, extinction ratio and reference wavelength also increase, and at the same time, the maximum electricfield intensity （EFI） in the inner of layer and the EFI at the interface drops off. Only the varying characteristic of p-polarization is associated with the Brewster＇ s angle. By analyzing the interface properties and defect distribution in layers, it is found that the p-polarization laser-induced damage threshold of polarizer increases as the incident increases. The results indicate that in the allowable range of p-polarization, the bigger the angle of incidence on polarizer is, though the transmittance of p-polarization decreases slightly, the better the extinction ratio is and the lower the EFI in the layer is.