Degenerate Four-Wave Mixing near the Excitonic Resonances of Bulk MoS$_{\mathrm{2}}$

ORAL

Abstract

MoS$_{\mathrm{2}}$ is a two-dimensional semiconductor with a direct bandgap in the visible regime (1.88 eV), making it a promising candidate for optoelectronic and photonic applications, such as Raman enhancement. However, near the bandgap, the photoluminescence of MoS$_{\mathrm{2\thinspace }}$disturbs the Raman signal, reducing enhancement. In the bulk limit, MoS$_{\mathrm{2}}$ transitions to an indirect semiconductor while retaining the direct excitonic transition at 1.88 eV. In our experiment, we observe a four-wave mixing (FWM) signal generated by a bulk MoS$_{\mathrm{2}}$ flake using a broadband coherent anti-Stokes Raman spectroscopy setup. We observe a resonance at 680 nm, corresponding to the energy of the excitonic transition. This resonance occurs due to the increased third-order nonlinear susceptibility at wavelengths near the excitonic transition. This phenomenon could open the path to using MoS$_{\mathrm{2}}$ as a flat substrate for four-wave mixing processes such as coherent anti-Stokes Raman spectroscopy..

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Authors

  • Brian Ko

    Baylor University/Texas A&M University

  • Zhenrong Zhang

    The Cyclotron Institute at Texas A&M University, SF Austin State Univ, Texas A&M University, University of Texas at Arlington, Weatherford College, Texas A&M University/Baylor University/Princeton University, Baylor University/Texas A&M University, Texas A&M University/Baylor University, Baylor University

  • Zhenrong Zhang

    The Cyclotron Institute at Texas A&M University, SF Austin State Univ, Texas A&M University, University of Texas at Arlington, Weatherford College, Texas A&M University/Baylor University/Princeton University, Baylor University/Texas A&M University, Texas A&M University/Baylor University, Baylor University

  • Zhenrong Zhang

    The Cyclotron Institute at Texas A&M University, SF Austin State Univ, Texas A&M University, University of Texas at Arlington, Weatherford College, Texas A&M University/Baylor University/Princeton University, Baylor University/Texas A&M University, Texas A&M University/Baylor University, Baylor University

  • Zhenrong Zhang

    The Cyclotron Institute at Texas A&M University, SF Austin State Univ, Texas A&M University, University of Texas at Arlington, Weatherford College, Texas A&M University/Baylor University/Princeton University, Baylor University/Texas A&M University, Texas A&M University/Baylor University, Baylor University