Transition from electromagnetically induced transparency to Electromagnetically Induced Absorption Utilizing Phase-Change Material Vanadium Dioxide Based on Circularly Polarized Waves

Abstract

A circular-polarization metastructure (MS) with switchable functions connected to the transition from electromagnetically induced transparency (EIT) to electromagnetically induced absorption (EIA) is theoretically proposed under the action of circularly polarized (CP) waves in the terahertz (THz) band. Additionally, we use the phase-change material vanadium dioxide (VO 2 ) to achieve functional transformation. The MS is mainly composed of two metal bright modes and a VO 2 resonator. When the VO 2 is insulating, the EIT with a high and wide transmission window is realized between 0.460 THz and 0.911 THz due to the coupling between two bright modes. Once VO 2 reaches the metal state, the original high transmission window is transformed into the high absorption window and the phenomena from EIT to EIA (vice versa) are successfully achieved from 0.460 THz to 0.911 THz. The group delays and group index of EIT are 161 ps and 1126, respectively. The simulation results of EIT and EIA are verified by fitting the theoretical two-oscillator model. • The proposed MS provides a new idea to manipulate the transition between EIT and EIA. • Multiple parameters can be adjusted to manipulate the transmission amplitude and frequency. • The presented structure is great transparency or absorption for the EM wave. • The thickness of the proposed MS is subwavelength. • The proposed MS can be applied to antenna fields and wave plates.