Direct observation of split-mode exciton-polaritons in a single MoS 2 nanotube

• Published in: Nanoscale horizons 2024-05, Vol.9 (6), p.968-975
• Main Authors: Galimov, A I, Kazanov, D R, Poshakinskiy, A V, Rakhlin, M V, Eliseyev, I A, Toropov, A A, Remškar, M, Shubina, T V
• Format: Article
• Language: English
• ISSN: 2055-6756; 2055-6764
• DOI: 10.1039/D4NH00052H

A single nanotube synthesized from a transition metal dichalcogenide (TMDC) exhibits strong exciton resonances and, in addition, can support optical whispering gallery modes. This combination is promising for observing exciton-polaritons without an external cavity. However, traditional energy-momentum-resolved detection methods are unsuitable for this tiny object. Instead, we propose to use split optical modes in a twisted nanotube with the flattened cross-section, where a gradually decreasing gap between the opposite walls leads to a change in mode energy, similar to the effect of the barrier width on the eigenenergies in the double-well potential. Using micro-reflectance spectroscopy, we investigated the rich pattern of polariton branches in single MoS tubes with both variable and constant gaps. Observed Rabi splitting in the 40-60 meV range is comparable to that for a MoS monolayer in a microcavity. Our results, based on the polariton dispersion measurements and polariton dynamics analysis, present a single TMDC nanotube as a perfect polaritonic structure for nanophotonics.