2025/11/17 by Nan Zhang, Zhang, Nan, Ya Yan Lu +1
Materials Science · Engineering · Physics and Astronomy · #Metamaterials and Metasurfaces Applications #Plasmonic and Surface Plasmon Research #Electromagnetic Scattering and Analysis
paper · pdf · doi:10.48550/arxiv.2511.12900
We study a class of bound states in the continuum (BICs) in all-dielectric periodic structures, near which resonant states approach ideal circularly polarized states (CPSs). We term these BICs \em asymptotically circularly polarized BICs (\em acp-BICs) and identify two types: single-angle and all-angle. Single-angle \em acp-BICs permit convergence to left- or right-handed CPSs only along a single momentum-space direction, whereas all-angle \em acp-BICs exhibit convergence to CPSs of a single handedness throughout the entire momentum space, rendering them exceptionally promising for chiral optical applications. We reveal that the existence of \em acp-BICs is underpinned by total reflection of circularly polarized waves. Moreover, all-angle \em acp-BICs qualify as super-BICs, with uniform nearby polarization being an intrinsic property. In addition, a bifurcation theory is developed to analyze the emergence of genuine CPSs from \em acp-BICs under C2-symmetric structural perturbations. Our results suggest \em acp-BICs as a platform for singular and chiral optical responses in all-dielectric systems.