Transition Metal Dichalcogenides for High-index Nanophotonics, Nonlinear Optics and Strong Light-matter Coupling

Title: Transition Metal Dichalcogenides for High-index Nanophotonics, Nonlinear Optics and Strong Light-matter Coupling
When: Thursday, June 15, (2023), 12:00
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor).
Speaker: Timur Shegai, Chalmers University of Technology, Gothenburg, Sweden.

In this talk, I will summarize our recent experimental attempts to realize strong light-matter interactions using excitons and trions in TMD-plasmon systems [1-4], as well as present experimental observations of high-index in several selected TMDs [5]. The latter opens exciting possibilities for high-index nanophotonics applications [6], which in combination with the high oscillator strength of the excitonic transitions promises an interesting self-coupled polaritonic platforms where material excitations (excitons, phonons, etc.) self-couple to the optical modes (e.g. geometrical Mie modes or Fabry-Pérot resonances) supported by nanostructured media with substantially high background refractive indexes [7-10]. This approach can be utilized to witness the regimes of perfect absorption and strong coupling in ultrathin MoS2 structures [11] as well as generalized to other material platforms, including perovskites, hexagonal boron nitride, J-aggregates and even water droplets [12]. I will also present our recent observations of enhanced second-harmonic generation in mono- and bilayers of ReS2 and demonstrate light-induced defect-assisted phase transitions in these materials [13]. Finally, I will discuss ways to engineer and study ultrasharp edges in multilayers TMDs, which can allow to combine the unique edge physics with nanophotonic concepts such as metasurfaces, optoelectronics, and even photoelectrocatalysis [14].

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4. Munkhbat, B. et al. ACS Nano 2020, 14, (1), 1196-1206.
5. Munkhbat, B. et al. ACS Photonics 2022, 9, (7), 2398-2407.
6. Munkhbat, B. et al. Laser Photon. Rev. 2023, 17, (1), 2200057.
7. Munkhbat, B. et al. ACS Photonics 2018, 6, (1), 139-147.
8. Verre, R. et al. Nat. Nanotech. 2019, 14, (7), 679-683.
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13. Küçüköz, B. et al. ACS Photonics 2022, 9, (2), 518-526.
14. Munkhbat, B. et al. Nat. Commun. 2020, 11, (1), 4604.