Plasmonic hot–electron transfer in the strong coupling regime

Abstract

Hybrid states that result from strong light-matter coupling have been shown to exhibit material properties that differ significantly from those of the uncoupled states, including the work function[1], chemical reactivity[2], ultra-fast energy relaxation[3, 4] and electrical conductivity[5]. In this talk we will show that waveguide-plasmon polaritons, which result from the strong coupling of localised plasmon resonances in metal nanowires and waveguide modes (see diagram of figure 1), result in hybrid states exhibiting hot-electron characteristics that are modulated by the degree of plasmon-exciton coupling. Ultra-fast visible pump, near-IR probe spectroscopy measurements reveal a strong correlation between the amplitude of the transient signals, attributed to electrons residing in the semiconductor, and the degree of hybridization of waveguide and plasmon excitations. Our work has potential implications for the design of efficient opto-electronic devices that exploit plasmonic hot carrier phenomena.