Improving the extinction ratio by a novel sandwiched two-layer grating polarizer

摘要

The high efficiency and the wideband properties are not easy to be obtained by the conventional binary grating-based polarizer. Although the grating polarizer was demonstrated in experiments, the performance should be improved further to meet the practical applications. A novel sandwiched two-layer grating polarizer is presented to improve the efficiency and the bandwidth. Such a polarizer can have advantages of high efficiency of the sandwiched grating and wide bandwidth of the two-layer grating. The grating depths of two layers are optimized for the special duty cycle of 0.3 and the given period. The diffraction efficiency and the incident bandwidth of the novel grating polarizer are improved greatly compared with the conventional simple grating and the sandwiched single-layer grating. Moreover, high extinction ratio can be shown in both two orders and the moderate fabrication tolerance should be good guideline for practical applications.