Design of the subwavelength dual-layer metallic nanowire-grid polarizer

Abstract

A novel subwavelength dual-layer metallic nanowire-grid polarizer is designed for visible region. The difference between the designed and the available nanowire-grid polarizer is that the former adds a high refractive index dielectric layer between the substrate and the dielectric grating. It is found that the high refractive index dielectric layer can improve the performance of polarizer. Effects of the thickness of the high refractive index dielectric layer, the incident angle and the duty cycle on the TM polarization transmission efficiency as well as the extinction ratios are analyzed using rigorous couple-wave theory. Based on the simulation results, a polarizer with high TM transmission efficiency and high extinction ratios over a wide incident angle is designed. It gives TM transmission efficiency over 79% and extinction ratios higher than 56.6dB until the incident angle is <i>&theta;</i>= 60&deg