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arXiv · 2203.02081

Twisted-light-induced exciton wave packets in transition-metal dichalcogenide monolayers

Guan-Hao Peng·Oscar Javier Gomez Sanchez·Wei-Hua Li·Ping-Yuan Lo·Shun-Jen Cheng
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Abstract

We present a comprehensive theoretical investigation of the photo-generated excitons in transition-metal dichalcogenide monolayers (TMD-ML's) by Laguerre-Gaussian beams, a celebrated kind of twisted lights (TL's) carrying quantized orbital angular momenta (OAM). We show that the photo-excitation of TL incident to a TMD-ML leads to the formation of spatially localized exciton wave packets, constituted by the superposition of finite-momentum exciton states determined by the intriguing interplay between the multiple degrees of freedom of the optical and excitonic subsystems. Consequently, the TL-induced exciton wave packets yield profound directional photo-luminescences whose polar-angle-dependences are encoded by the transferred optical OAM and azimuthal angle part, despite OAM-irrelevant, optically resolves the exchange-split longitudinal and transverse exciton bands. Interestingly, the application of linearly polarized TL onto a valley-excitonic system mimics an exciton multiplexer allowing for selectively detecting the individual valley-mixed exciton bands, which are normally hardly measured spectrally.

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Guan-Hao Peng, Oscar Javier Gomez Sanchez, Wei-Hua Li, Ping-Yuan Lo, Shun-Jen Cheng. 2022-03-04. Twisted-light-induced exciton wave packets in transition-metal dichalcogenide monolayers. https://arxiv.org/abs/2203.02081

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