Active control of quasi-bound states in the continuum in VO ₂ metasurfaces for enhanced terahertz sensing

factor analysis and multipolar decomposition reveal that this improvement arises from the tunable nature of the accidental BIC. Additionally, incorporating an optical gain substrate mitigates performance degradation due to intrinsic losses. This work integrates BIC physics with active materials to achieve superior terahertz sensing, offering new insights for the design of advanced sensor devices.