Nanophotonics in modern plasmonics and nanolasers

The light–matter interaction at the metal-dielectric interface lead to the discovery of plasmonics, whose name has its origin in the coherent collective oscillation of free electrons, named plasmons, which appears in this regime. The fundamental and applied research in plasmonics has evolved fantastically, giving rise to other subfields, such as nanoplasmonics, when the interaction occurs in the nanoscale. By starting with photonics and plasmonics as the basis for such modern research areas, this chapter deals with some aspects of modern photonics and plasmonics at the nanoscale, including the optical source of photons based on those processes, as nanolasers. Initially, a review of the basic aspects of plasmonics will be given, building upon the existing literature. Thereafter, recent aspects of the young field of nanoplasmonics, as the modern interface between nanophotonics and plasmonics, will be introduced, followed by some nonlinear nanoplasmonics in gold nanorods, besides applications in surface-enhanced Raman spectroscopy (SERS). In going further, plasmonic nanolasers and random lasers will be reviewed, including a literature update on spasers, a plasmonic laser. The chapter will conclude with an outlook in this field from the author’s point of view.