Resonance Energy Transfer on a Metallic Thin Film: Characteristic Distance and the Origin of Plasmon Enhancement

Resonance energy transfer (RET) around metallic structures has received considerable attention during the past few years. In this study, we analyze the mechanisms of RET on a metallic thin film in the framework of macroscopic quantum electrodynamics and investigate the distance dependence of RET enhancements. Our theoretical analysis shows that the mechanisms of RET can be separated into mirror dipoles, surface plasmons, and retardation. Besides, we find the characteristic distance of RET coupled with surface plasmon polaritons and it can be modified by varying the thickness of thin film, indicating that RET can be significantly enhanced at a short range.