Modes interplay and dynamics in the second harmonic generation of plasmonic nanostructures

Area of Science:

• Nanophotonics and Plasmonics
• Nonlinear Optics
• Computational Electromagnetics

Background:

• Second harmonic generation (SHG) is a key nonlinear optical process.
• Understanding SHG dynamics in metallic nanostructures is crucial for optical device applications.
• Previous studies often assumed quadrupolar radiation in spherical nanoparticles.

Purpose of the Study:

• To investigate the full wave surface integral equation computation of SHG dynamics in metal spheres and nanorods.
• To reveal the dynamics of modes supported by nanostructures and their influence on nonlinear response.
• To demonstrate methods for boosting SHG signals and reducing computational time.

Main Methods:

• Full wave surface integral equation computation.
• Analysis of mode dynamics in metallic nanostructures (spheres and nanorods).
• Investigation of size-induced redshift and geometric manipulation of eigenmodes.

Main Results:

• The interplay between different modes dictates the nonlinear response.
• Nanostructure geometry can be adjusted to manipulate size-induced redshift and boost SHG signals.
• SHG radiation in spherical nanoparticles is not exclusively quadrupolar.
• An efficient method for reducing SHG calculation time was introduced.

Conclusions:

• The study provides insights into controlling nonlinear optical phenomena in plasmonic nanostructures.
• Findings enable tailored design of nanostructures for enhanced SHG at specific frequencies.
• The research challenges existing assumptions about SHG radiation multipolarity and offers computational efficiency improvements.