Quantum plasmonics: new opportunity in fundamental and applied photonics

Surface plasmons allow electromagnetic fields to be confined to subwavelength scale, well beyond the classical optical diffraction limit. With continuous reduction of optical mode volume into the deep subwavelength scale, a new era of quantum plasmonics opens up that investigates the quantum behavior of surface plasmons and their interactions with matter. This emerging and exciting field creates many new opportunities in advancing the boundaries of fundamental science and applied quantum technology. This review covers recent breakthroughs from three unique and important perspectives: the fundamental quantum properties of plasmon-polaritons, plasmon-polaritons interacting with quantum emitters, and plasmon-polaritons stepping into quantum technology. A clear development map of quantum plasmonics is also established for the reader.