Ultrafast dynamics in 2D materials and heterostructures visualized with time- and angle-resolved photoemission

Thomas K. Allison, Zachary H. Withers, Ziling Li, Jin Bakalis, Sergii Chernov, Shuyu Cheng, Gerd Schönhense, Xu Du, Roland Kawakami, Alice Kunin

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The optical and electronic properties of two-dimensional (2D) materials make them attractive for a variety of applications in quantum information processing, solar-energy harvesting, and catalysis. However, the dynamics of electrons, holes, and excitons formed after photo-excitation are often complex and involve many states that are optically dark, making their characterization with optical spectroscopy alone difficult. We present our recent work imaging the quantum states of 2D materials and their heterostructures in momentum space using time- and angle-resolved photoemission. A unique combination of tunable ultrashort extreme ultraviolet (XUV) pulses with 61 MHz repetition rate and time-of-flight momentum microscopy (ToF k-mic) enables the parallel recording of electron dynamics in all states across the full Brillouin zone after perturbative excitation. We will present results on pseudospin dynamics in graphene, valley circular dichroism in monolayer WS2, and hybridized excitons in MoSe2/WS2 bilayers.

Original languageEnglish (US)
Title of host publicationUltrafast Phenomena and Nanophotonics XXVIII
EditorsMarkus Betz, Abdulhakem Y. Elezzabi
ISBN (Electronic)9781510670280
StatePublished - 2024
EventUltrafast Phenomena and Nanophotonics XXVIII 2024 - San Francisco, United States
Duration: Jan 29 2024Jan 31 2024

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceUltrafast Phenomena and Nanophotonics XXVIII 2024
Country/TerritoryUnited States
CitySan Francisco

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


  • frequency combs
  • high-order harmonic generation
  • momentum microscopy
  • Photoelectron spectroscopy


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