Two-dimensional exciton-polariton-light guiding by transition metal dichalcogenide monolayers

Two-dimensional (2D) monolayer-thick materials with a direct bandgap, such as MoS2, WSe2, and other transition metal dichalcogenides (TMDCs), are being actively explored for future nanophotonic applications in the visible and UV ranges. Here I show that a monolayer of TMDCs is capable of supporting a guided optical mode below the exciton resonance-a 2D exciton-polariton. I evaluate the characteristics of these guided modes and conditions required for their existence, including derivations of mode dispersion relations, mode confinements, and propagation lengths. The visible or near-IR mode is confined to within roughly a micrometer of the monolayer and has a propagation length exceeding 100 mu m. This light guiding ability in the visible and IR ranges makes TMDC monolayers a versatile and potentially attractive platform for future optoelectronic devices. (C) 2015 Optical Society of America