Actively tunable terahertz electromagnetically induced transparency analogue based on vanadium-oxide-assisted metamaterials

We investigate the active control of electromagnetically induced transparency (EIT) analogue based on terahertz (THz) metamaterials integrated with vanadium oxide(VO2). Due to the insulator-to-metal transition of VO2, the amplitude of EIT peak can be actively modulated with significant modulation depth. Meanwhile the group delay within the transparent window can also be dynamically tuned, bringing the active control of slow light effect. Furthermore, we also introduce independently tunable transparent peaks based on double-peak EIT, and the group delay within each transparent window can also be independently controlled. Finally, based on broadband EIT, the active tuning toward quality factor of EIT is also realized. This work introduces active EIT control with multiple degree of freedom by employing VO2, and can find potential applications in future wireless THz communication systems as multi-channel filters, switches, spacers, logic gates and modulators.