Selective photoexcitation of finite-momentum excitons in monolayer mos2 by twisted light

Shun Jen Cheng*, Ting Hua Lu*, Yann Wen Lan*, Kristan Bryan Simbulan, Teng De Huang, Guan Hao Peng, Feng Li, Oscar Javier Gomez Sanchez, Jhen Dong Lin, Chun I. Lu, Chan Shan Yang, Junjie Qi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


Twisted light carries a well-defined orbital angular momentum (OAM) of l per photon. The quantum number l of its OAM can be arbitrarily set, making it an excellent light source to realize high-dimensional quantum entanglement and ultrawide bandwidth optical communication structures. In spite of its interesting properties, twisted light interaction with solid state materials, particularly two-dimensional materials, is yet to be extensively studied via experiments. In this work, photoluminescence (PL) spectroscopy studies of monolayer molybdenum disulfide (MoS2), a material with ultrastrong light-matter interaction due to reduced dimensionality, are carried out under photoexcitation of twisted light. It is observed that the measured spectral peak energy increases for every increment of l of the incident light. The nonlinear l-dependence of the spectral blue shifts is well accounted for by the analysis and computational simulation of this work. More excitingly, the twisted light excitation revealed the unusual lightlike exciton band dispersion of valley excitons in monolayer transition metal dichalcogenides. This linear exciton band dispersion is predicted by previous theoretical studies and evidenced via this work's experimental setup.

Original languageEnglish
Pages (from-to)3481-3489
Number of pages9
JournalACS Nano
Issue number2
Publication statusPublished - 2021 Feb 23


  • Light-matter interaction
  • Lightlike exciton dispersion
  • Orbital angular momentum
  • Transition metal dichalcogenides
  • Twisted light

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


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