Composite‐Assisted Phase‐Matching: Efficient Wavelength Conversion in Nonlinear Optical Composite Materials Containing Metal Nanoparticles

Abstract

A novel phase‐matching scheme which is based on the dispersion compensation in the nonlinear optical composite materials containing metal nanoparticles is proposed. Anomalous dispersion originating from the plasmon resonance in metal nanoparticles compensates the dispersion of the host nonlinear material, leading to the perfect phase‐matching and high efficiency of nonlinear optical wavelength conversion. The effectiveness of this approach is theoretically demonstrated, taking third‐order nonlinear processes such as the direct third‐harmonic generation and four‐wave mixing in ZnO composites containing silica‐core–silver‐shell nanoparticles as examples. The results show that with the proposed phase‐matching scheme, unprecedentedly high conversion efficiency can be obtained compared with preceding results in third‐order nonlinear optical solid‐state materials.

Forward and Backward Switching of Nonlinear Unidirectional Emission from GaAs Nanoantennas

“…To address the first challenge, initially, metallic nanoantennas have been extensively employed for the nonlinear processes due to the strong near-field enhancement arising from the coherent oscillations of conduction electrons near the surface of plasmonic structures. ,− However, the performance of nonlinear plasmonics is restricted by high Ohmic losses, small mode volumes, and low laser damage threshold. Subsequently, high-index dielectric nanostructures such as silicon (Si) and germanium (Ge) nanoantennas, which support both electric and magnetic Mie-type resonances, were considered as promising alternatives to overcome these limitations of nonlinear nanoplasmonics. − It has been shown that through exploiting different electric and magnetic multipolar resonances and taking advantage of various interferences between the optical modes, one can induce strong near-field enhancements and subsequently tailor the field distributions inside the nanostructures. ,, This capability was offered as a promising route to significantly facilitate the nonlinear interactions. ,− …”