Terahertz modulators based on VO2–metal hybridized metamaterials for free switching between BIC and quasi-BIC states

Optical devices based on bound states in the continuum (BIC) have attracted significant attention owing to their various potential applications. However, when changing their structural parameters, most of these devices exhibit a BIC resonance, limiting their utilization in practical applications requiring dynamic modulation. This paper proposes two modulators based on VO2–metal hybridized metamaterials for a dynamic modulation in the terahertz regime. By replacing a part of the metallic structure with structured vanadium dioxide (VO2), we could enable switching between the BIC and quasi-BIC states via a temperature-dependent insulator-to-metal transition in VO2. The Q factor and the asymmetry parameters of the modulators were found to be consistent with the inverse quadratic law, demonstrating the existence of a BIC state. •A VO2-metal hybridized metamaterial is proposed for the free switching between BIC and quasi-Bic states by temperature control.•The vanadium dioxide metal-mixed metamaterial proposed in this paper has a high modulation depth of 0.86.•In this paper, the modulation depth of vanadium dioxide metal mixed metamaterials changes with temperature.•The multipole expansion of the metamaterial is calculated, and it is confirmed that the excitation of the quasi-BIC state.