Theoretical study in dual-channel quasi bound-states in the continuum in YaBa2Cu3O7 ceramic split-ring resonator metasurface and multi-functional responsive sensing

In recent years, quasi-bound-states in the continuum (q-BIC) have been widely studied, and mechanisms for exciting q-BIC have been continuously proposed. In the research of q-BIC, symmetric-protecting q-BIC is an important branch, and as a classic metasurface design scheme, a split-resonant ring (SRR) has been found to excite q-BIC. A dual-channel q-BIC design is proposed based on the symmetry-breaking property of YaBa₂Cu₃O₇ ceramic SRR metasurface. Two asymmetry parameters are introduced into YaBa₂Cu₃O₇ ceramic SRR metasurface, which can excite q-BIC channels at two frequency positions, respectively. This characteristic is utilized to analyze sample thickness and detect refractive index separately at two q-BIC channels. The q-BIC channel 1 is used as a responsive thickness sensor to detect the thickness of the sample layer. The q-BIC channel 2 realizes the function of refractive index detection. Herein, a method is provided for exciting dual-channel q-BIC and utilizing the high quality factor of q-BIC to achieve multi-functional sensing. It has enormous potential value in biomedical and environmental monitoring fields.