Active nanophotonics

Nanostructured dielectric materials provide unprecedented control over light-matter interactions via sculpting of near- and far-field effects, such as confinement of electromagnetic radiation at the nanoscale, beaming of the scattered radiation, and enhancement of nonlinear effects. In this chapter, we review different dielectric or hybrid metal-dielectric nanostructures and their arrays for active nanophotonics, more specifically, for enhancing the emission of various quantum emitters. We first discuss weak and strong coupling regimes of emitters and optical modes where enhancement of the Purcell factor and photoluminescence as well as formation of polaritonic states can take place. Then, we introduce various nanostructures, such as high-index metasurfaces and a nanoparticle-on-a-mirror that can boost light-matter interactions from quantum dots, transition metal dichalcogenides, and intersubband transitions. The nanophotonics-enabled enhancement and directional control of the emission of quantum emitters will not only enable next-generation photonic devices, but also benefit quantum information sciences via bright and fast single-photon sources.