Enhancing Near‐Infrared Emission From AgAuSe Quantum Dots With Dielectric Metasurface Supporting Bound States in the Continuum

ABSTRACT The ability to tune spontaneous emission dynamics is pivotal for advancing quantum photonic technologies, such as micro‐lasers and quantum sensors. Colloidal quantum dots (QDs) are promising candidates due to their high quantum yield and spectral tunability. However, their radiative decay rates are fundamentally limited by the local photonic density of states in conventional environments. Here, we demonstrate a tailored dielectric metasurface that resonantly couples to environmentally benign AgAuSe QDs. The metasurface is designed to support a magnetic dipole resonance and an electric dipole mode, the latter arises from the broken symmetry of a protected BIC state. The synergistic interplay between these modes creates a highly localized photonic environment, leading to a pronounced 15‐fold amplification of NIR‐II photoluminescence at room temperature. Optical characterization confirms that the enhancement stems from resonant coupling to quasi‐bound states in the continuum (quasi‐BIC) mode, drastically increases radiative decay rate. The use of CMOS‐compatible, all‐dielectric silicon nanostructures enables scalable fabrication. We demonstrate that the precise control of the resonance wavelength via structural symmetry breaking allows for selective fluorescence enhancement. This work establishes a quasi‐BIC‐based light‐matter interaction scheme for sustainable quantum emitters and provides a design blueprint for developing non‐toxic, high‐efficiency quantum light sources and lasers.