title: Control of plasmon emission and dynamics at the transition from classical to quantum coupling.
abstract: With nanosecond radiative lifetimes, quenching dominates over enhancement for conventional fluorescence emitters near metal interfaces. We explore the fundamentally distinct behavior of photoluminescence (PL) with few-femtosecond radiative lifetimes of a coupled plasmonic emitter. Controlling the emitter-surface distance with subnanometer precision by combining atomic force and scanning tunneling distance control, we explore the unique behavior of plasmon dynamics at the transition from long-range classical resonant energy transfer to quantum coupling. Because of the ultrafast radiative plasmon emission, classical quenching is completely suppressed. Field-enhanced behavior dominates until the onset of quantum coupling dramatically reduces emission intensity and field enhancement, as verified in concomitant tip-enhanced Raman measurements. The entire distance behavior from tens of nanometers to subnanometers can be described using a phenomenological rate equation model and highlights the new degrees of freedom in radiation control enabled by an ultrafast radiative emitter near surfaces.
authors.affiliation: Department of Physics, Department of Chemistry, and JILA, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Vasily
authors.initials: V
authors.lastname: Kravtsov
authors.forename: Samuel
authors.initials: S
authors.lastname: Berweger
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Atkin
authors.forename: Markus B
authors.initials: MB
authors.lastname: Raschke
keywords: Plasmonic emitter; photoluminescence; quantum coupling; radiative lifetime; tunneling