  Resonant dielectric nanoparticles (RDNs) made of materials with large
positive dielectric permittivity, such as Si, GaP, GaAs, have become a powerful
platform for modern light science, enabling various fascinating applications in
nanophotonics and quantum optics. In addition to light localization at the
nanoscale, dielectric nanostructures provide electric and magnetic resonant
responses throughout the visible and infrared spectrum, low dissipative losses
and optical heating, low doping effect and absence of quenching, which are
interesting for spectroscopy and biosensing applications. In this review, we
present state-of-the-art applications of optically resonant high-index
dielectric nanostructures as a multifunctional platform for light-matter
interactions. Nanoscale control of quantum emitters and applications for
enhanced spectroscopy including fluorescence spectroscopy, surface-enhanced
Raman scattering (SERS), biosensing, and lab-on-a-chip technology are surveyed.
We describe the theoretical background underlying these effects, overview
realizations of specific resonant dielectric nanostructures and hybrid
excitonic systems, and outlook the challenges in this field, which remain open
to future research.
