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

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.