Valley-selective Optical Stark Effect Probed by Kerr Rotation

ORAL

Abstract

The valley pseudospin in transition metal dichalcogenide (TMDC) monolayers is a promising degree of freedom for coherent control. The optical Stark effect allows for valley-selective manipulation of energy levels in WS2 and WSe2 using ultrafast optical pulses. Despite these advances, understanding of valley-selective optical Stark shifts in TMDCs has been limited by reflectance-based detection methods where the signal is small and prone to background effects. We show that polarization-sensitive, time-resolved Kerr rotation is less sensitive to background effects, providing a five-fold improvement in the signal-to-noise ratio of the Stark effect optical signal and a more precise estimate of the energy shift. This increased sensitivity allows for observation of an optical Stark shift in monolayer MoS2 that exhibits both valley- and energy-selectivity, demonstrating the promise of this method for investigating this effect in other layered materials and heterostructures.

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Presenters

  • Trevor LaMountain

    Applied Physics Program, Northwestern University

Authors

  • Trevor LaMountain

    Applied Physics Program, Northwestern University

  • Hadallia Bergeron

    Department of Materials Science and Engineering, Northwestern University, Materials Science and Engineering, Northwestern University

  • Itamar Balla

    Department of Materials Science and Engineering, Northwestern University, Materials Science and Engineering, Northwestern University

  • Teodor Stanev

    Department of Physics, Northwestern University, Department of Physics and Astronomy, Northwestern University

  • Mark Hersam

    Department of Material Science, Northwestern University, Northwestern Univ., Department of Materials Science and Engineering, Northwestern University, Materials Science and Engineering, Northwestern University

  • Nathaniel Stern

    Department of Physics, Northwestern University, Department of Physics and Astronomy, Northwestern University, Physics and Astronomy, Northwestern University