Quantum plasmonics and how to fix Purcell’s formula for spontaneous emission enhancement - Stephen Hughes

The study of quantum light-matter interactions near metal cavities can be used to explore fundamental quantum optical regimes such as modified spontaneous emission of a single photon emitter. Metal resonators create localized surface plasmons which give rise to pronounced resonances in a similar way to high-Q cavity structures, but with incredibly small mode volumes. However, metal nanostructures are significantly more complicated to model because of material losses and thus standard mode expansion techniques fail. This talk will introduce several regimes of quantum nanoplasmonics with a focus on light-matter interactions between a single quantum dot and a metal resonator. We first show why Purcell’s formula is wrong for any finite Q cavity [1], and we show how to unambiguously fix this formula for any resonator including metallic cavities. We will also introduce the phenomena of strong coupling [2] and resonance fluorescence (Mollow triplet) of a driven quantum dot near a metal nanoparticle [3], and show how these well known quantum optical effects are influenced by bath-induced coupling from the metal resonator. [1] P. Kristensen, C. Van Vlack, S. Hughes, Generalized mode volume for leaky optical cavities, Optics Letters 37, 1649 (2012). [2] C. Van Vlack, P. T. Kristensen, and S. Hughes, Spontaneous emission spectra and quantum light-matter interactions from a strongly-coupled quantum dot metal-nanoparticle system, Physical Review B 85, 0765303 (2012). [3] Rong-Chun Ge, C. Van Vlack, P. Yao, Jeff. F. Young, S. Hughes, Accessing quantum nanoplasmonics in a hybrid quantum-dot metal nanosystem: Mollow triplet of a quantum dot near a metal nanoparticle, Physical Review B 87, 205425 (2013).