Ultrathin WS<sub>2</sub> Polariton Waveguide for Efficient Light Guiding
Seong Won Lee, Jong Seok Lee, Woo Hun Choi, Su‐Hyun Gong
Abstract
Abstract Light confinement to sub‐wavelength scales is actively studied for nanophotonic applications because it gives rise to intriguing optical properties with enhanced light‐matter interaction. Herein, an ultrathin exciton–polariton waveguide based on a WS 2 multilayer is proposed for sub‐wavelength light guiding. A WS 2 waveguide supports guided exciton–polariton modes even with a few tens of nanometers of thickness. It is theoretically confirmed that the WS 2 waveguide has significantly lower propagation loss than a plasmonic mode, although its thickness may be similar to that of a plasmonic waveguide. By injecting white light into a fabricated WS 2 waveguide, light guiding is experimentally demonstrated through a 20 nm thick WS 2 waveguide. Notably, this study integrated the WS 2 waveguide with a WSe 2 monolayer to demonstrate the coupling of monolayer emission to the polariton waveguide. The results suggest that WS 2 multilayers provide a novel material platform with potential for nanophotonic applications, including ultrathin optical integrated circuits.