Reconfigurable Quasi‐BIC Metasurface for Terahertz Manipulation Spanning Different Polarization States

Metasurfaces enable precise manipulation of multiple degrees of freedom of electromagnetic waves, yet few existing studies achieve manipulation of multiple polarization modes of electromagnetic waves across the full space. Reconfigurable metasurfaces have recently emerged as a research focus for achieving multi‐channel manipulation of electromagnetic waves due to their flexible active tuning capabilities. Inspired by the concept of bound states in the continuum (BIC), strong electromagnetic responses can be excited in metasurfaces through the introduction of structural asymmetry. This paper presents a general and straightforward design strategy for a reconfigurable quasi‐BIC metasurface, which leverages the quasi‐BIC mechanism to induce linear dichroism in the transmission channel and to generate circular dichroism in the reflection channel. By leveraging the reversible insulator‐metal‐transition (IMT) of vanadium dioxide (VO 2 ), dynamic switching of terahertz waves between transmission and reflection channels under two distinct polarization modes is achieved. Experimental results agree well with simulation, validating the effective multi‐channel terahertz manipulation using the proposed reconfigurable metasurface. This metasurface holds potential for applications in terahertz wireless communication, holographic imaging, and information encryption.