Observation of Bragg polaritons in monolayer tungsten disulphide

Autor: Wei Huang, Xuewen Zhang, Xu Wang, Jingzhi Shang, Ting Yu, Zheng Sun, Weihuang Yang, Lishu Wu
Přispěvatelé: School of Physical and Mathematical Sciences
Rok vydání: 2021
Předmět:
Zdroj: Nano Research. 15:1479-1485
ISSN: 1998-0000
1998-0124
DOI: 10.1007/s12274-021-3691-6
Popis: Strong light-matter interactions involved with photons and quasiparticles are fundamentally interesting to access the wealthy many-body physics in quantum mechanics. The emerging two-dimensional (2D) semiconductors with large exciton binding energies and strong quantum confinement allow to investigate exciton-photon coupling at elevated temperatures. Here we report room-temperature formation of Bragg polaritons in monolayer semiconductor on a dielectric mirror through the exciton-Bragg photon coupling. With the negative detuning energy of ∼ 30 meV, angle-resolved reflection signals reveal anti-crossing behaviors of lower and upper polariton branches at ±18° together with the Rabi splitting of 10 meV. Meanwhile, the strengthened photoluminescence appears in the lower polariton branch right below the anti-crossing angles, indicating the presence of the characteristic bottleneck effect caused by the slowing exciton-polariton energy relaxation towards the band minimum. The extracted coupling strength is between the ones of weak and distinct strong coupling regimes, where the eigenenergy splitting induced by the moderate coupling is resolvable but not large enough to fully separate two polaritonic components. Our work develops a simplified strategy to generate exciton-polaritons in 2D semiconductors and can be further extended to probe the intriguing bosonic characteristics of these quasiparticles, such as Bose-Einstein condensation, polariton lasing and superfluidity, directly at the material surfaces.[Figure not available: see fulltext.] Ministry of Education (MOE) National Research Foundation (NRF) Submitted/Accepted version We thank the support of the Ministry of Education of Singapore (MOE 2019-T2-1-044), Singapore National Research Foundation under the Competitive Research Programs (No. NRF-CRP-21- 2018-0007), the Fundamental Research Funds for the Central Universities of China, National Natural Science Foundation of China (Nos. 61904151 and 51173081), Natural Science Foundation of Shaanxi (No. 2020JM-108), Joint Research Funds of Department of Science & Technology of Shaanxi Province and Northwestern Polytechnical University (No. 2020GXLHZ-020), Ministry of Education of China (IRT1148), and Zhejiang Provincial Natural Science Foundation of China (No. LGG19F040003).
Databáze: OpenAIRE
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