Hybrid Photonic–Plasmonic Bound States in Continuum for Enhanced Light Manipulation

Light can be influenced by permittivity changes in optical resonators to enable optical sensors, modulators, and switches. The best performance (intensity change per permittivity change) is observed for dielectric bound states in the continuum (BICs). However, the lateral size must be large to explore their full potential. In this work, hybrid photonic–plasmonic BICs (hybrid BICs) fabricated using a cost‐efficient scalable fabrication method are experimentally realized. While plasmonics is known to enable strong miniaturization, regarding BICs, the introduction of losses is thought to reduce device performance. Hybrid BICs in two operation modes, specular geometry and diffraction geometry, are also theoretically analyzed. While the reduced device performance is confirmed for hybrid BICs investigated in a specular geometry, a different result is obtained using diffraction geometry: hybrid BICs using diffraction geometry exhibit greatly increased performance compared to purely dielectric ones. Hybrid BICs using diffraction geometry as powerful tool to enhance the capability of light manipulation are thus considered.