Efficient Third Harmonic Generation from Metal-Dielectric Hybrid Nanoantennas

Area of Science:

• * Photonics and Nanotechnology
• * Nonlinear Optics
• * Plasmonics

Background:

• * High refractive index dielectric nanoantennas offer significant potential for nonlinear nano-optics due to inherent nonlinearities and field enhancement capabilities.
• * Existing dielectric nanoantennas face limitations in maximizing nonlinear responses within nanoscale volumes.

Purpose of the Study:

• * To investigate the enhancement of nonlinear optical responses in dielectric nanoantennas by integrating metallic components.
• * To demonstrate the synergistic effects of metal-dielectric hybrid nanostructures on light-matter interactions at the nanoscale.

Main Methods:

• * Fabrication of hybrid nanostructures combining a gold (Au) nanoring with a silicon (Si) nanodisk.
• * Utilizing the plasmonic resonance of the Au nanoring to excite and enhance the anapole mode of the Si nanodisk.
• * Characterization of nonlinear optical properties, specifically third harmonic generation (THG).

Main Results:

• * The metal-dielectric hybrid nanostructure significantly boosts the anapole mode, leading to enhanced electric fields within the dielectric.
• * Achieved a high third harmonic conversion efficiency of 0.007% at a wavelength of 440 nm.
• * Demonstrated tunability of enhanced third harmonic emission across the optical spectrum by modifying geometrical parameters.

Conclusions:

• * Combining metallic and dielectric nanoantennas in hybrid structures is a viable strategy to significantly enhance nonlinear optical effects.
• * These findings open new avenues for efficient nanoscale nonlinear optics, particularly in the visible light range.
• * The developed hybrid nanoantennas show promise for advanced photonic devices and applications.