Plasmon-enhanced second harmonic generation in the laser-irradiated cubic metal nanoparticles

TL;DR

This paper presents a theoretical study of plasmon-enhanced second harmonic generation in cubic metal nanoparticles, revealing significant field and signal enhancement compared to spherical particles.

Contribution

It develops a comprehensive theory accounting for electromagnetic singularities at cubic nanoparticle surfaces, a first in this context.

Findings

Strong enhancement of local field strength in nanocubes

Significant increase in second harmonic signal in cubic nanoparticles

Comparison shows cubic particles outperform spherical ones in SHG

Abstract

The plasmon-enhanced second harmonic generation in the subwavelength neutral metal cubic nanoparticles is calculated for the first time in the hydrodynamic and cold plasma approximations. The theory is developed that takes into account all singularities of the electromagnetic field at the cubic nanoparticle surface. The results are compared to the linear case for the nanocube and to those for a spherical nanoparticle. In the latter case, they demonstrate very strong enhancement of the local field strength and the second harmonic signal.