A New Method for Inverse Designing Metasurfaces of Bound States in the Continuum

The distinctive feature of metasurface BIC lies in its high quality factor, which significantly enhances the interaction between light and matter. The inverse design of metasurface BIC further amplifies the practical applicability and prospects of this characteristic. However, due to the strong coupling and nonlinear properties of quasi-BIC, the true underlying physical interpretation remains elusive, rendering the reverse-engineering process exceedingly intricate. This greatly limits its real-world applications. In this paper, we propose a novel approach for the inverse design of metamaterial BIC devices based on the resonant frequency of transmission spectra and the quasi-BIC point frequency. This method employs Coupled Mode Theory and the Huygens principle to explore the relationship between resonant frequencies and quasi-BIC frequencies within the theoretical model. Simulation results substantiate the feasibility of utilizing desired resonant and quasi-BIC frequencies for the corresponding metamaterial BIC devices. Furthermore, this method is universally applicable to BIC devices utilizing two distinct metamaterial structures, irrespective of specific configurations.