Third-harmonic generation from gold nanowires of rough surface considering classical nonlocal effect

Area of Science:

• Plasmonics
• Nonlinear Optics
• Materials Science

Background:

• Traditional local models fail to explain enhanced nonlinear optical phenomena in nanostructures.
• Understanding nonlocal effects is crucial for predicting and optimizing light-matter interactions at the nanoscale.

Purpose of the Study:

• To investigate the impact of nonlocal dielectric response on third-order harmonic generation (THG) in gold nanowires.
• To compare the nonlocal model with the traditional local model for THG efficiency.
• To explore the influence of surface morphology on THG anisotropy.

Main Methods:

• Theoretical modeling of third-order harmonic generation incorporating nonlocal dielectric effects.
• Simulations of electromagnetic field interactions with gold nanowires featuring rough surfaces.
• Analysis of THG efficiency as a function of incidence angle and surface morphology.

Main Results:

• Nonlocal dielectric response significantly enhances THG by several orders of magnitude compared to the local model.
• Field penetration into fine nanostructures on the metal surface is identified as the likely cause of enhancement.
• Anisotropic THG efficiency is observed due to inhomogeneous surface morphology.

Conclusions:

• The nonlocal dielectric model provides a more accurate description of THG in nanostructured metals.
• Nonlocal effects are critical for understanding and predicting enhanced nonlinear optical responses in plasmonic systems.
• The findings offer insights into experimental observations and guide future nanophotonic device design.