Plasmonic Waveguides: Enhancing quantum electrodynamic phenomena at nanoscale

The emerging field of plasmonics may lead to enhanced light–matter interactions at extremely nanoscale regions. Plasmonic (metallic) devices promise to efficiently control classical and quantum properties of light. Plasmonic waveguides are usually employed to excite confined electromagnetic modes at nanoscale that can strongly interact with matter. Analysis shows that nanowaveguides share similarities with their low-frequency microwave counterparts. In this article, we review ways to study plasmonic nanostructures coupled to quantum optical emitters from a classical electromagnetic perspective. Quantum emitters are mainly used to generate single-photon quantum light that can be employed as a quantum bit, or “qubit,” in envisioned quantum information technologies. We demonstrate different ways to enhance a diverse range of quantum electrodynamic phenomena based on plasmonic configurations by using the Green’s function formalism, a classical dyadic tensor. More specifically, spontaneous emission and superradiance are analyzed through Green’s function-based field quantization. The exciting new field of quantum plasmonics could lead to a plethora of novel optical devices for communications and computing applications in the quantum realm, such as efficient single-photon sources, quantum sensors, and compact on-chip nanophotonic circuits.