基于严格耦合波理论的亚波长金属光栅偏振器设计

The Design of the Subwavelength Wire-Grid Polarizers Based on Rigorous Couple-Wave Theory

亚波长周期结构光栅具有传统光栅所不具有的特殊性质.针对仿生微纳导航系统敏感波段0.52-0.59μm的要求,采用严格耦合波理论分析了不同光栅材料、光栅面型及光栅结构参数对TM偏振透射率及透射消光比的影响,设计了对应的金属偏振光栅.所设计的光栅与传统金属光栅不同之处在于基底和光栅之间增加了氟化镁介质,在垂直入射条件下,TM偏振透射率及消光比都增大.在0.38μm^0.40μm及0.50μm^0.76μm全光波段内,TM偏振透射率都大于50%,消光比都大于170,达到了宽带宽、TM偏振透射率及透射消光比都较高的要求.

According to the request of the sensitive wave band of 0. 52-0. 59μm of the bionic micro-nano navigation system, effects of different grating materials, grating shapes and grating parameters on the TM polarization transmission efficiency as well as the extinction ratio are analyzed by using the rigorous couplewave theory, and the corresponding wire-grid polarizer is designed. When it works at the normal incidence, difference between the designed grating and conventional wire-grid is that the former adds the magnesium fluoride between the fundus and the grating, and the TM polarization transmission efficiency and the extinction ratio are increased . The TM polarization transmission efficiencies are more than 50 percentages and the extinction ratios are more than 170 when the incident wavelength is varied from 0. 38 μm to 0. 40 μm or from 0. 50μm to 0. 76μm, which meets the expectations for wide band, high TM polarization transmission efficiencies and high transmission extinction ratios.