Tunable terahertz metamaterial based on vanadium dioxide for electromagnetically induced transparency and reflection

. To realize the electromagnetically induced transparency (EIT) or reflection (EIR) effect in the terahertz band, many metamaterial structures have been proposed. However, these structures usually have a single function of EIT effect or EIR effect, and it is a major challenge for a metamaterial structure to perform multiple functions. In this study, a switchable multifunctional hybrid metamaterial is proposed, which realizes the combined function of tunable EIT effect and EIR effect at THz regions through the integration of vanadium dioxide (VO2) and metal metamaterial. Moreover, by changing the conductivity of VO2, the intensity modulations of EIT window and EIR window reach 36.11% and 50.59%, respectively. The surface current distribution and electric field responses are used to analyze the physical mechanisms of the EIT effect and the EIR effect. In addition, the active tuning mechanism of the metamaterial is theoretically explored based on the "two-particle" model. The designed hybrid metamaterial provides a simple approach to realize tunable EIT effect and EIR effect in THz metamaterials. This work opens up a possible way to achieve switchable functions (EIT or EIR) in a single device, which may find potential applications in optical switches, sensing, filtering, and slow light devices.