The strong coupling between a single quantum emitter and confined electromagnetic field offers unique opportunity for fundamental physics as well as its potential applications in quantum technologies such as quantum light sources, quantum networks, and quantum sensing. Plasmonic cavities confine electromagnetic field in subwavelength region that makes the strong coupling with single quantum emitter possible even at room temperature. In this article, a conceptual introduction is provided to single quantum emitter strong coupling with plasmonic cavities along with a comprehensive review of recent experimental and theoretical advances. The phenomenon of strong light–matter coupling is examined, followed by a conceptual overview of plasmonic cavities and their unique electromagnetic properties. An overview of theoretical predictions and a detailed discussion of recent experimental advances demonstrating strong coupling between single quantum emitter and confined electromagnetic field of plasmonic cavities are then presented. The article is concluded by offering a perspective on the future of this rapidly evolving field, which promises to uncover even more intriguing physics and extend its impact across a wide range of scientific disciplines.
Satyendra Nath Gupta (Sat,) studied this question.