基于超表面的多通道窄带滤光片研究

Research on multi-channel narrow-band filter based on metasurface

  • 摘要: 针对传统多通道窄带滤光片存在尺寸大、通道选择性差的问题,该文设计了由分布式布拉格反射镜(DBR)和超表面微纳阵列组成的多通道窄带滤光片。利用传输矩阵法分析单侧DBR介质周期以及缺陷层折射率对透射光谱的影响,并优化了窄带滤光片结构。通过Comsol Multiphysics 软件搭建窄带滤光片单元结构进行模拟仿真,研究了超表面以及入射角对窄带滤光片滤波特性的影响。仿真结果表明:通过调节超表面边长能够调控窄带滤光片的中心波长,在634 nm~714 nm的红光波段均可以获得一个带宽窄、透射率高的透射峰;每一个通道的的中心波长都可以通过调节超表面边长来调控,从而实现多个光谱通道的窄带滤光;入射光线小角度范围(0°~10°)内的变化对滤波性能的影响甚微。该结果为多通道窄带滤光片的设计提供了一条新的思路。

     

    Abstract: Aiming at the problems of large size and poor channel selectivity of traditional multi-channel narrow-band filters, a multi-channel narrow-band filter composed of distributed Bragg reflector (DBR) and metasurface micro-nano array was designed. The effects of the period of one sided DBR medium and the refractive index of the defect layer on the transmission spectrum were analyzed by using the transfer matrix method, and the structure of the narrow-band filter was optimized. The unit structure of the narrow-band filter was built by Comsol Multiphysics software for simulation, and the influence of the metasurface and the incident angle on the filtering characteristics of the narrow-band filter was studied. The simulation results show that the central wavelength of the narrow-band filter can be tuned by adjusting the edge length of the metasurface, and a transmission band with narrow bandwidth and high transmittance can be obtained in the red light band from 634 nm to 714 nm. The central wavelength of each channel can be adjusted. By adjusting the side length of the metasurface, the narrow-band filtering of multiple spectral channels can be achieved. The changes in the small angle range (0°~10°) of the incident light have little effect on the filtering performance. The results provide a new idea for the design of multi-channel narrow-band filters.

     

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