Tunable asymmetric transmission across stretchable chiral metamaterial

Switchable asymmetric transmission with broadband polarization conversion in vanadium dioxide-assisted terahertz metamaterials

In this paper, we theoretically present a vanadium dioxide (VO2)-integrated metamaterial, which can achieve switchable single- and double-band asymmetric transmission (AT) in terahertz regions. When VO2 acts as a metal, the presented metamaterial device exhibits a single-band AT effect. In contrast, when VO2 transitions from the metal to the insulating state, a dual-band AT effect can be realized for the presented metamaterials. Also, it is demonstrated that there is a broadband near-perfect orthogonal polarization conversion associated with the AT effect. And the operating mechanisms are elucidated by using the Fabry-Pérot-like cavity model and the electromagnetic field distributions. Moreover, the presented nanostructure exhibits a robust tolerance for the incidence angle. Our designed metamaterial may have potential applications for switchable multi-functional devices in terahertz regimes.

High-efficiency modulation of broadband polarization conversion with a reconfigurable chiral metasurface

We demonstrate an electrically biased reconfigurable chiral metasurface for controlling the polarization conversion and asymmetric transmission in a broadband manner. The reconfigurable metasurface is constructed with coupled three-layer complementary split-ring resonator (CSRR) arrays and is loaded with tunable electronic components to achieve dynamic control of reconfigurable chiral coupling in the CSRRs by simply tuning the external voltage on the structure. It is found that the polarization conversion in the metasurface can be effectively and continuously tuned in both experiments and simulations in a broadband frequency range. Meanwhile, the reconfigurable metasurface shows an asymmetric transmission (AT) effect in a broadband range for a polarized wave. The proposed reconfigurable chiral metasurface based on the active tuning of connection in the meta-structure with few functional layers is confirmed as an effective strategy for multi-functional polarization manipulation. The reported broadband properties of the chiral metasurface are promising for polarization manipulation in optical bands and applications in wireless communication.