Dual-frequency asymmetric transmission metasurface for independent terahertz reflection and transmission wavefront control

In this paper, a dual-frequency asymmetric transmission metasurface composed of four-layered anisotropic units is proposed. By manipulating the propagation direction of y-polarized plane waves, the metasurface can operate in two distinct modes. When the frequency of the incident wave is 0.44 THz, a y-polarized plane wave can be efficiently converted into an x-polarized wave. While, when the frequency of the incident wave transforms to 0.73 THz, a y-polarized plane wave can be reflected and deflected at an angle of 30 degrees. Due to the integrated design of this encoded metasurface, reflected and transmitted wavefronts can be controlled simultaneously within a shared aperture, which provides a convenient approach for multifunctional devices. The simulation results show that the proposed metasurface achieves good performance as expected, realizing beam focusing and anomalous reflection functionalities in dual terahertz frequency bands. This highlights its potential for advancements in modern optics, optical communications, and sensing technologies.