Compound Hertzian Chain Model for Copper-Carbon Nanocomposites' Absorption Spectrum

TL;DR

This paper models the optical absorption spectrum of copper-carbon nanocomposites using a chain of coupled plasmonic dipoles, considering nanoparticle interactions and experimental validation.

Contribution

It introduces a compound Hertzian chain model for copper nanoparticles in carbon composites, accounting for plasmonic coupling and size effects, validated by experimental data.

Findings

Absorption peaks depend on particle size and spacing.

The model accurately predicts experimental absorption spectra.

Coupled plasmon resonance frequencies are derived analytically.

Abstract

The infrared range optical absorption mechanism of Carbon-Copper composite thin layer coated on the Diamond-Like Carbon (DLC) buffer layer has been investigated. By consideration of weak interactions between copper nanoparticles in their network, optical absorption is modeled using their coherent dipole behavior induced by the electromagnetic radiation. The copper nanoparticles in the bulk of carbon are assumed as a chain of plasmonic dipoles, which have coupling resonance. Considering nearest neighbor interactions for this metallic nanoparticles, surface plasmon resonance frequency ({\omega}\neg0) and coupled plasmon resonance frequency ({\omega}\neg1) have been computed. The damping rate versus wavelength is derived which leads to the derivation of the optical absorption spectrum in the term of {\omega}\neg0 and {\omega}\neg1. The dependency of the absorption peaks to the particle-size and the particle mean spacing is also investigated. The absorption spectrum is measured for different Cu-C thin films with various Cu particle size and spacing. The experimental results of absorption are compared with the obtained analytical ones.