# Plasmon enhanced second harmonic generation by periodic arrays of triangular nanoholes coupled to quantum emitters

## TL;DR

This study investigates how periodic triangular nanohole arrays enhance second harmonic generation through plasmonic effects and coupling with quantum emitters, revealing optimal conditions for energy conversion and spectral features.

## Contribution

It introduces a comprehensive 3D nonlinear hydrodynamic model to analyze plasmonic nanohole arrays coupled with quantum emitters, highlighting their nonlinear optical properties and enhancement mechanisms.

## Key findings

- Second harmonic generation is maximized at localized surface plasmon resonance.
- Coupling with quantum emitters creates distinct spectral peaks in SH signals.
- Both Coulomb and convective electron interactions significantly influence nonlinearity.

## Abstract

Optical properties of periodic arrays of nanoholes of a triangular shape with experimentally realizable parameters are examined in both linear and nonlinear regimes. Utilizing fully vectorial three-dimensional approach based on the nonlinear hydrodynamic Drude model describing metal coupled to Maxwells equations and Bloch equations for molecular emitters we analyze linear transmission, reflection, and nonlinear power spectra. Rigorous numerical calculations demonstrating second and third harmonic generation by the triangular hole arrays are performed. It is shown that both the Coulomb interaction of conduction electrons and the convective term contribute on equal footing to the nonlinear response of metal. It is demonstrated that the energy conversion efficiency in the second harmonic process is the highest when the system is pumped at the localized surface plasmon resonance. When molecular emitters are placed on a surface of the hole array lineshapes of the second harmonic signal exhibits three peaks corresponding to second harmonics of the localized surface plasmon mode and upper and lower polaritonic states.

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Source: https://tomesphere.com/paper/1908.01077