Towards compact phase-matched and waveguided nonlinear optics in atomically layered semiconductors

Abstract

Nonlinear frequency conversion provides essential tools for light generation, photon entanglement, and manipulation. Transition metal dichalcogenides (TMDs) possess huge nonlinear susceptibilities and 3R-stacked TMD crystals further combine broken inversion symmetry and aligned layering, representing ideal candidates to boost the nonlinear optical gain with minimal footprint. Here, we report on the efficient frequency conversion of 3R-MoS2, revealing the evolution of its exceptional second-order nonlinear processes along the ordinary (in-plane) and extraordinary (out-of-plane) directions. By measuring second harmonic generation (SHG) of 3R-MoS2 with various thickness - from monolayer (~0.65 nm) to bulk (~1 μm) - we present the first measurement of the in-plane SHG coherence length (~530 nm) at 1520 nm and achieve record nonlinear optical enhancement from a van der Waals material, >10^4 stronger than a monolayer. It is found that 3R-MoS2 slabs exhibit similar conversion efficiencies of lithium niobate, but within propagation lengths >100-fold shorter at telecom wavelengths. Furthermore, along the extraordinary axis, we achieve broadly tunable SHG from 3R-MoS2 in a waveguide geometry, revealing the coherence length in such structure for the first time. We characterize the full refractive index spectrum and quantify both birefringence components in anisotropic 3R-MoS2 crystals with near-field nano-imaging. Empowered with these data we assess the intrinsic limits of the conversion efficiency and nonlinear optical processes in 3R-MoS2 attainable in waveguide geometries. Our analysis highlights the potential of 3R-stacked TMDs for integrated photonics, providing critical parameters for designing highly efficient on-chip nonlinear optical devices including periodically poled structures, resonators, compact optical parametric oscillators and amplifiers, and optical quantum circuits.

References in corpus (6)

• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Chip-based photon quantum state sources using nonlinear optics
• Optical imaging of strain in two-dimensional crystals
• Generalized 4 $\times$ 4 Matrix Formalism for Light Propagation in Anisotropic Stratified Media: Study of Surface Phonon Polaritons in Polar Dielectric Heterostructures
• All-optical polarization and amplitude modulation of second-harmonic generation in atomically thin semiconductors
• Strong light-matter coupling in MoS${}_2$

Cited by in corpus (17)

• Van der Waals Materials for Applications in Nanophotonics
• Roadmap for Photonics with 2D Materials
• Advances in ultrafast plasmonics
• Quasi-phase-matched up- and down-conversion in periodically poled layered semiconductors
• Time-modulated near-field radiative heat transfer
• Nonlinear optics in 2D materials: from classical to quantum
• Excitonic signatures of ferroelectric order in parallel-stacked MoS${}_2$
• Polaritonic Quantum Matter
• Enhanced photon-pair generation from a van der Waals metasurface
• Spatiotemporal imaging of nonlinear optics in van der Waals waveguides
• Interface second harmonic generation enhancement in hetero-bilayer van der Waals nanoantennas
• Photonics in Flatland: Challenges and Opportunities for Nanophotonics with 2D Semiconductors
• Raman Forbidden Layer-Breathing Modes in Layered Semiconductor Materials Activated by Phonon and Optical Cavity Effects
• Ultrafast all-optical switching in nonlinear 3R-MoS${}_2$ van der Waals metasurfaces
• Intermediates of Forming Transition Metal Dichalcogenide Heterostructures Revealed by Machine Learning Simulations
• Advancements in Entangled Photon Pairs in 2D Van der Waals Materials for On-chip Quantum Applications
• Blue-shifted dispersive waves and broadband UV emission using dual-core SiN waveguides