Ultrafast all-optical switching in nonlinear 3R-MoS${}_2$ van der Waals metasurfaces

Abstract

Second-order nonlinear optical processes are fundamental to photonics, spectroscopy, and information technologies, with material platforms playing a pivotal role in advancing these applications. Here, we demonstrate the exceptional nonlinear optical properties of the van der Waals crystal 3R-MoS${}_2$, a rhombohedral polymorph exhibiting high second-order optical susceptibility (${\chi }^{(2)}$) and remarkable second-harmonic generation (SHG) capabilities. By designing high quality factor resonances in 3R-MoS${}_2$ metasurfaces supporting quasi-bound states in the continuum (qBIC), we first demonstrate SHG efficiency enhancement exceeding 10${}^2$. Additionally, by using degenerate pump-probe spectroscopy, we harness the C${}_{3v}$ system's symmetry to realize ultrafast SHG polarization switching with near-unity modulation depth. The operation speeds are limited only by the excitation pulse duration, allowing its characterization via the nonlinear autocorrelation function. These findings establish 3R-MoS${}_2$ as a transformative platform for nanoscale nonlinear optics, offering large conversion efficiencies and ultrafast response times for advanced pulse measurement devices, integrated photonics, and quantum technologies.

arXiv comment4 figures main text, 18 pages

References in corpus (17)

• Asymmetric metasurfaces with high-$Q$ resonances governed by bound states in the continuum
• Observation of Intense Second Harmonic Generation from MoS${}_2$ Atomic Crystals
• Applications of Bound States in the Continuum in Photonics
• Transition metal dichalcogenide nanodisks as high-index dielectric Mie nanoresonators
• Giant optical anisotropy in transition metal dichalcogenides for next-generation photonics
• Continuous wave second harmonic generation enabled by quasi-bound-states in the continuum on gallium phosphide metasurfaces
• Optical imaging of strain in two-dimensional crystals
• Strong light-matter interaction with self-hybridized bound states in the continuum in monolithic van der Waals metasurfaces
• All-optical polarization and amplitude modulation of second-harmonic generation in atomically thin semiconductors
• Towards compact phase-matched and waveguided nonlinear optics in atomically layered semiconductors
• Van der Waals Materials for Applications in Nanophotonics
• Quasi-phase-matched up- and down-conversion in periodically poled layered semiconductors
• Nonlinear Optics: a look from the interaction time viewpoint and what it portends
• Exciton Assisted Deeply Subwavelength Nano-Photonics
• Chiral photonic super-crystals based on helical van der Waals homostructures
• Spatiotemporal imaging of nonlinear optics in van der Waals waveguides
• Probing Noncentrosymmetric 2D Materials by Fourier Space Second Harmonic Imaging