Probing Dark Excitons in Monolayer MoS$_2$ by NonLinear Two-Photon Spectroscopy

Fuente: arXiv
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Main Authors: Qian, Chenjiang, Villafañe, Viviana, Soubelet, Pedro, Ji, Peirui, Stier, Andreas V., Finley, Jonathan J.
Format: Preprint
Published: 2023
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author Qian, Chenjiang
Villafañe, Viviana
Soubelet, Pedro
Ji, Peirui
Stier, Andreas V.
Finley, Jonathan J.
author_facet Qian, Chenjiang
Villafañe, Viviana
Soubelet, Pedro
Ji, Peirui
Stier, Andreas V.
Finley, Jonathan J.
contents We report a new dark exciton in monolayer MoS$_2$ using second harmonic generation spectroscopy. Hereby, the spectrally dependent second harmonic generation intensity splits into two branches, and an anticrossing is observed at $\sim$ 25 meV blue detuned from the bright neutral exciton. These observations are indicative of coherent quantum interference arising from strong two-photon light-matter interaction with an excitonic state that is dark for single photon interaction. The existence of the dark state is supported by engineering its relaxation to bright localized excitons, mediated by vibrational modes of a proximal nanobeam cavity. We show that two-photon light-matter interaction involving dark states has the potential to control relaxation pathways induced by nanostructuring the local environment. Moreover, our results indicate that dark excitons have significant potential for nonlinear quantum devices based on their nontrivial excitonic photophysics.
format Preprint
id arxiv_https___arxiv_org_abs_2309_02303
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Probing Dark Excitons in Monolayer MoS$_2$ by NonLinear Two-Photon Spectroscopy
Qian, Chenjiang
Villafañe, Viviana
Soubelet, Pedro
Ji, Peirui
Stier, Andreas V.
Finley, Jonathan J.
Mesoscale and Nanoscale Physics
We report a new dark exciton in monolayer MoS$_2$ using second harmonic generation spectroscopy. Hereby, the spectrally dependent second harmonic generation intensity splits into two branches, and an anticrossing is observed at $\sim$ 25 meV blue detuned from the bright neutral exciton. These observations are indicative of coherent quantum interference arising from strong two-photon light-matter interaction with an excitonic state that is dark for single photon interaction. The existence of the dark state is supported by engineering its relaxation to bright localized excitons, mediated by vibrational modes of a proximal nanobeam cavity. We show that two-photon light-matter interaction involving dark states has the potential to control relaxation pathways induced by nanostructuring the local environment. Moreover, our results indicate that dark excitons have significant potential for nonlinear quantum devices based on their nontrivial excitonic photophysics.
title Probing Dark Excitons in Monolayer MoS$_2$ by NonLinear Two-Photon Spectroscopy
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2309.02303