High performance visible spectral polarizer using double-layer alternating metal grating and metamaterial substrate

A polarizer is a crucial component in polarization imaging technology. In practical applications, an excellent polarizer can significantly improve optical imaging quality, target detection ability, and the reliability of polarization imaging systems. To address the problems of high cost, difficult preparation, low transmittance, and extinction ratio, which are found in existing polarizers, this paper proposes a high performance visible spectral polarizer, where a double-layer alternating metal subwavelength grating is adopted, referred to as DAMG-Polarizer. The polarizer consists of a metamaterial substrate, which is covered with subwavelength metal gratings on its upper and lower surfaces. The simulation results demonstrate that the transverse magnetic (TM) transmittance of the polarizer ranges from 55.5% to 75.8% in the 350–800 nm visible wavelength region, with an average extinction ratio (ER) of 74.6 dB, and a maximum of 85 dB. Additionally, the polarizer has good process tolerance and exhibits less dependence on the incident angle. Compared to the existing metal grating polarizers, the proposed polarizer has superior performance and achieves high transmittance and a high extinction ratio simultaneously.