Bound States in the Continuum in Photonics and Metasurfaces: From Phenomena to Applications

Bound states in the continuum (BICs) refer to nonradiative eigenmodes located within the radiation continuum, possessing infinitely high Q‐factor and enabling exceptionally strong light–matter interactions. BICs have found applications across various domains in photonics and metasurfaces, including nonlinear optical enhancement, vortex beam generation, sensor technology, microlasers, and other related areas. This work starts by classifying the phenomena of BICs and introducing the theoretical formation mechanisms and topological characteristics. Then, the current and advanced applications based on BIC‐devices are highlighted. Lastly, this work discusses the current challenges in studies related to BICs, such as structural precision, material selection, and measurement difficulties, and prospect the possible potentials in future developments. This review provides a theoretical background and application prospects of BIC‐engineered devices in optical and photonics fields, laying a solid foundation for future industrial applications.