Switchable terahertz metamaterial for perfect absorption and electromagnetically induced transparency

Abstract This study proposes a switchable functional terahertz metamaterial based on phase-change vanadium dioxide (VO 2 ). The device’s unique feature lies in its ability to dynamically switch between broadband perfect absorption and electromagnetic-induced transparency (EIT) by exploiting the reversible phase transition of VO 2 between metallic and insulating states. When VO 2 is in its high-conductivity (200000 S m −1 ) metallic state, the device functions as a perfect absorber, exhibiting exceeding 90% absorption within the 0.79–1.71 THz frequency band and a relative absorption bandwidth nearly 74%. Upon transitioning to the low-conductivity (20 S m −1 ) insulating state, the device exhibits typical EIT effects, generating a high-transmittance transparent window near 0.74 THz accompanied by a group delay of up to 8.5 ps, demonstrating significant slow-light properties.