  The most important direction in the development of fundamental and applied
physics is the study of the properties of optical systems at the nanoscale in
order to create optical and quantum computers, biosensors, single-photon
sources for quantum informatics, devices for DNA sequencing, sensors of various
fields, etc. In all these cases, nanoscale light sources - dye molecules,
quantum dots (epitaxial or colloidal), color centers in crystals, and
nanocontacts in metals - are of key importance. In the nanoenvironment, the
characteristics of these elementary quantum systems - pumping rates, radiative
and non-radiative decay rates, the local density of states, lifetimes, level
shifts - experience changes that can be used intentionally to create nanoscale
light sources with desired properties. This review presents an analysis of
actual theoretical and experimental works in the field of elementary quantum
systems radiation control using plasmonic and dielectric nanostructures,
metamaterials, and nanoparticles made from metamaterials.
