Multi-wavelength near infrared cross polarization converters

Two types of cross polarization converters (CPCs) that can simultaneously work at several wavelengths in the reflection mode in near infrared spectrum range are proposed. The first type (type I) is constructed of an L-shaped perforated silver layer (top layer) printed on a dielectric material backed by a gold ground plane, which can work at three frequencies due to the excitation of three different modes. The second type (type II) is realized by adding another silver layer with the same pattern as the top layer between top layer and ground plane. Type II CPCs can work at even more frequencies (≥5) simultaneously compared to type I CPCs because the couplings between the two silver layers provide more freedom for generating polarization conversion working frequencies. Numerical simulations have verified the performance of the proposed CPCs.