High-q resonances in silicon nanoparticle coupled to nanopit

Nanoparticle-on-mirror systems have shown promise in nanophotonics for enhancing light emission from quantum sources. In this study, we introduce a new subclass of hybrid systems called nanoparticle-in-pit. We conducted simulations to analyze the scattering properties and near-field enhancement of emission for a silicon nanoparticle near a gold surface and in a nanopit. Our focus was on investigating the impact of different geometric parameters of a nanoantenna on the optical resonances. The proposed nanoantenna exhibited Fano-like resonances, achieving a high Q-factor of up to 100 and subwavelength near-field confinement. Additionally, for silicon nanoparticles in the visible spectrum, we demonstrated the presence of various resonances that can enhance both the absorption and emission of quantum emitters by adjusting the geometric parameters of the nanoantenna. For real applications, we suggest the core-shell configuration of a silicon nanoparticle with a dielectric shell as a more suitable one. The properties of silicon nanoparticle-based nanoantennas presented in this study surpass those of a silicon nanoparticle on a gold surface, opening up possibilities for nanophotonic applications using high-index dielectric nanoparticles.