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 WS2 multilayer is proposed for sub-wavelength light guiding. A WS2 waveguide supports guided exciton–polariton modes even with a few tens of nanometers of thickness. It is theoretically confirmed that the WS2 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 WS2 waveguide, light guiding is experimentally demonstrated through a 20 nm thick WS2 waveguide. Notably, this study integrated the WS2 waveguide with a WSe2 monolayer to demonstrate the coupling of monolayer emission to the polariton waveguide. The results suggest that WS2 multilayers provide a novel material platform with potential for nanophotonic applications, including ultrathin optical integrated circuits.
Bibliographical noteFunding Information:
The authors acknowledge the support from Prof. J. Joo and S. Lee for the fabrication process. This work was supported by the National Research Foundation of Korea (NRF‐2019R1A2C2003313 and NRF‐2022R1A4A1034315) and the National R&D Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT (2021M3F3A2A03017083). The authors acknowledge support provided by the Samsung Science and Technology Foundation (SSTF‐BA1902‐03) and the Korea University Grant.
© 2023 Wiley-VCH GmbH.
- exciton–polariton waveguides
- transition metal dichalcogenides waveguides
- ultrathin waveguides
- WS2 multilayer
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics