Second harmonic generation control in twisted bilayers of transition metal dichalcogenides

Abstract

The twist angle in transition metal dichalcogenide (TMD) heterobilayers is a compelling degree of freedom that determines electron correlations and the period of lateral confinement of moiré excitons. Here we perform polarization-resolved second harmonic generation (SHG) spectroscopy of MoS2/WSe2 heterostructures. We demonstrate that by choosing suitable laser energies the twist angle between two monolayers can be measured directly on the assembled heterostructure. We show that the amplitude and polarization of the SHG signal from the heterostructure are determined by the twist angle between the layers and exciton resonances at the SH energy. For heterostructures with close to zero twist angle, we observe changes of exciton resonance energies and the appearance of new resonances in the linear and non-linear susceptibilities.

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• Probing Dark Excitons in Monolayer MoS${}_2$ by NonLinear Two-Photon Spectroscopy
• Exciton-Sensitized Second-Harmonic Generation in 2D Heterostructures
• Highly tunable moiré superlattice potentials in twisted hexagonal boron nitrides
• Second harmonic generation due to spatial structure of radiation beam
• Review: Advanced characterization of the spatial variation of moiré heterostructures and moiré excitons
• Two dimensional semiconductors: optical and electronic properties
• Electrically tunable and enhanced nonlinearity of moiré exciton-polaritons in transition metal dichalcogenide bilayers
• Magnetic quadrupole dichroism in isotropic medium
• Silicon nanoantennas for tailoring the optical properties of MoS2 monolayers
• Determining the complex second-order optical susceptibility in macroscale van der Waals heterobilayers
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