Femtosecond exciton dynamics in WSe2 optical waveguides

Aaron J. Sternbach, Simone Latini, Sanghoon Chae, Hannes Hübener, Umberto De Giovannini, Yinming Shao, Lin Xiong, Zhiyuan Sun, Norman Shi, Peter Kissin, Guang Xin Ni, Daniel Rhodes, Brian Kim, Nanfang Yu, Andrew J. Millis, Michael M. Fogler, Peter J. Schuck, Michal Lipson, X. Y. Zhu, James HoneRichard D. Averitt, Angel Rubio, D. N. Basov

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

Van-der Waals (vdW) atomically layered crystals can act as optical waveguides over a broad range of the electromagnetic spectrum ranging from Terahertz to visible. Unlike common Si-based waveguides, vdW semiconductors host strong excitonic resonances that may be controlled using non-thermal stimuli including electrostatic gating and photoexcitation. Here, we utilize waveguide modes to examine photo-induced changes of excitons in the prototypical vdW semiconductor, WSe2, prompted by femtosecond light pulses. Using time-resolved scanning near-field optical microscopy we visualize the electric field profiles of waveguide modes in real space and time and extract the temporal evolution of the optical constants following femtosecond photoexcitation. By monitoring the phase velocity of the waveguide modes, we detect incoherent A-exciton bleaching along with a coherent optical Stark shift in WSe2.

Original languageEnglish (US)
Article number3567
JournalNature communications
Volume11
Issue number1
DOIs
StatePublished - Dec 1 2020

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy

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