Amorphous Silicon Metasurface-Based Polarizer near 770 nm Wavelength Regime

A quarter wave plate operating at 770 nm based on amorphous silicon (a-Si) metasurface is designed. A birefringent array is realized by simulation design whose degree of circular polarization (DOCP) is 99.52% and transmission efficiency is 97%. The metasurface is fabricated with the electron beam lithography (EBL) and its optical properties are measured. The experimental results show that the transmission efficiency of the designed device is 87.23% and DOCP is 93.32% at 770 nm. The designed device has a high birefringence coefficient which is two orders of magnitude of traditional birefringent crystals. Further, the narrowband and broadband performance of the device is investigated. Some phenomena and regularity found in the simulation design may provide valuable ideas for the design of metasurface-polarizers.