Terahertz hybrid metamaterial switcher between asymmetric transmission and linear dichroism

• A switchable metamaterial is proposed for asymmetric transmission (AT) and linear dichroism in the THz regime. • The AT can be controlled from 90% to a negligible order of 10 %. • In the insulating phase of vanadium dioxide (VO 2 ), the structure achieves remarkable AT, with transmission of 0.95 in magnitude. • In the conductive state of VO 2 the proposed design showcases spin-selective absorption for incident THz waves. • Dual modality is achieved within a compact and multilayer structure, which opens promising pathways for tunable, on-demand optical properties. This work introduces a hybrid metamaterial that operates as a highly switchable device, dynamically transitioning between asymmetric transmission (AT) and linear dichroism (LD) functionalities within the terahertz (THz) spectrum. Leveraging the phase-transition properties of vanadium dioxide (VO 2 ), which shifts from an insulating to a conductive metallic state at elevated temperatures, the proposed metamaterial enables tunable control over its optical characteristics. In the insulating phase, the structure achieves remarkable AT, with transmission coefficients reaching 0.95, supporting selective polarization conversion over an extensive frequency range (0.2–1.0 THz). Upon transitioning VO 2 to a metallic state, the AT effect diminishes significantly, allowing the device to exhibit LD by selectively absorbing linearly polarized THz waves. This reconfigurable behavior underscores the potential of phase-change materials to advance the field of active THz metamaterials, with applications in polarization manipulation, selective THz absorption, and tunable optoelectronic devices.