Advances in Exciton‐Polaritons With Bound States in the Continuum

ABSTRACT Bound states in the continuum (BICs) are non‐radiative eigenmodes that paradoxically exist within the continuum of radiating waves. Their recent introduction into the photonic systems has revolutionized the paradigm of light‐matter interaction, giving rise to striking optical characteristics, such as ideally infinite Q ‐factors, topological polarization vortices, and a rich set of structured field singularities. Particularly, rapid progress has also been achieved in exciton‐polariton BICs, where the strong coupling between photonic BICs modes and semiconductor excitons introduces intrinsic strong nonlinearities and enables unconventional quantum phenomena. In this review, we first introduce the fundamental concepts of strong light‐matter coupling and optical BICs, as well as highlight the unique physics emerging from their intersection. We then summarize recent experimental advances in the BICs‐related strong coupling, polariton formation, and polariton condensation across various optical modes in both active and passive BICs metasurfaces. Finally, we discuss future opportunities, including continuous‐wave and electrically driven BICs polariton lasers, emergent quantum collective phases, moiré‐engineered BICs architectures, non‐Hermitian BICs exciton‐polaritons and BICs‐based polaritonic logic devices.