Van der Waals functionalization of ultrahigh-Q silica microcavities for ${\chi }^{(2)}$-${\chi }^{(3)}$ hybrid nonlinear photonics

Abstract

Optical nonlinear processes are indispensable in a wide range of applications including ultrafast laser sources, microscopy, metrology, and quantum information technologies. Combinations of the diverse nonlinear processes should further lead to the development of unique functionalities, but simultaneous use of second- and third-order nonlinear processes is generally difficult. Second-order effects usually overwhelm the higher-order ones, except in centrosymmetric systems where the second-order susceptibility vanishes to allow the use of the third-order nonlinearity. Here we demonstrate a hybrid photonic platform whereby the balance between second- and third-order susceptibilities can be tuned flexibly. Ultrahigh-Q silica microcavities capable of generating third-order effects are functionalized by atomically thin tungsten diselenide, and we observe cavity-enhanced second-harmonic generation and sum-frequency generation with continuous-wave excitation at a power level of only a few hundred microwatts. Pump power dependence exhibits drastic increase and saturation of the second-harmonic light, originating from the dynamic phase-matching process. We show that the coexistence of second- and third-order nonlinearities in a single device can be achieved by carefully choosing the size and the location of the two-dimensional material. Our approach can be generalized to other types of cavities, unlocking the potential of hybrid systems with controlled nonlinear susceptibilities for novel applications.

21 pages, 5 figures

References in corpus (7)

• Two-Dimensional Material Nanophotonics
• Tightly bound excitons in monolayer WSe2
• Resonantly enhanced second-harmonic generation using III-V semiconductor all-dielectric metasurfaces
• All-optical polarization and amplitude modulation of second-harmonic generation in atomically thin semiconductors
• Optically reconfigurable quasi-phase-matching in silicon nitride microresonators
• Parametric Nonlinear Optics with Layered Materials and Related Heterostructures
• Quantization of mode shifts in nanocavities integrated with atomically thin sheets

Cited by in corpus (2)

• Ultrafast acoustic modulation of second-harmonic generation in monolayer transition metal dichalcogenides
• Dielectric environment engineering via 2D material heterostructure formation on hybrid photonic crystal nanocavity