Directional emission from WS2 monolayer coupled to plasmonic Nanowire-on-Mirror Cavity

Abstract

Influencing spectral and directional features of exciton emission characteristics from 2D transition metal dichalcogenides by coupling it to plasmonic nano-cavities has emerged as an important prospect in nanophotonics of 2D materials. In this paper we experimentally study the directional photoluminescence emission from Tungsten disulfide (WS2) monolayer sandwiched between a single-crystalline plasmonic silver nanowire (AgNW) waveguide and a gold (Au) mirror, thus forming an AgNW-WS2-Au cavity. By employing polarization-resolved Fourier plane optical microscopy, we quantify the directional emission characteristics from the distal end of the AgNW-WS2-Au cavity. Given that our geometry simultaneously facilitates local field enhancement and waveguiding capability, we envisage its utility in 2D material-based, on-chip nanophotonic signal processing, including nonlinear and quantum optical regimes.