Exciton-Sensitized Second-Harmonic Generation in 2D Heterostructures

Abstract

The efficient optical second-harmonic generation (SHG) of two-dimensional (2D) crystals, coupled with their atomic thickness that circumvents the phase-match problem, has garnered considerable attention. While various 2D heterostructures have shown promising applications in photodetectors, switching electronics, and photovoltaics, the modulation of nonlinear optical properties in such hetero-systems remains unexplored. In this study, we investigate exciton sensitized SHG in heterobilayers of transition metal dichalcogenides (TMDs), where photoexcitation of one donor layer enhances the SHG response of the other as an acceptor. We utilize polarization-resolved interferometry to detect the SHG intensity and phase of each individual layer, revealing the energetic match between the excitonic resonances of donors and the SHG enhancement of acceptors for four TMD combinations. Our results also uncover the dynamic nature of interlayer coupling, as evidenced by the dependence of sensitization on interlayer gap spacing and the average power of the fundamental beam. This work provides insights into how interlayer coupling of two different layers can modify nonlinear optical phenomena in 2D heterostructures.

24 pages, 5 figures

References in corpus (13)

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• Anomalous Lattice Vibrations of Single and Few-Layer MoS2
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• Optical imaging of strain in two-dimensional crystals
• Electric-field switchable second-harmonic generation in bilayer MoS${}_2$ by inversion symmetry breaking
• Ultrafast charge-transfer dynamics in twisted MoS${}_2$/WSe${}_2$ heterostructures
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Cited by in corpus (4)

• Determining the complex second-order optical susceptibility in macroscale van der Waals heterobilayers
• Dual-Polarization SHG Interferometry for Imaging Antiparallel Domains and Stacking Angles of 2D Heterocrystals
• Enhanced second-harmonic generation from WS${}_2$/ReSe${}_2$ heterostructure
• Ubiquitous Antiparallel Domains in 2D Hexagonal Boron Nitride Uncovered by Interferometric Nonlinear Optical Imaging