Highly efficient asymmetric optical transmission based on the gradient metasurface and subwavelength grating

摘要

In this paper, an asymmetric transmission device by combining the gradient metasurface and the subwavelength grating is proposed and investigated numerically. The gradient metasurface produces a transmitted wave with a certain angle upon normal incidence. The subwavelength grating can block light under the condition of normal incidence, although it can transmit light with an angle realized by the gradient metasurface. All materials employed in the proposed device are dielectric. The asymmetric transmission device exhibits high working efficiency and possesses a high-contrast ratio up to 41 dB. Our results are beneficial in designing devices with high-performance asymmetric optical transmission.