Optical far-infrared properties of graphene monolayer and multilayers

TL;DR

This paper investigates the optical properties of graphene monolayers and multilayers in the far-infrared spectrum, considering various physical parameters and plasmon dispersion, revealing characteristic reflectance features related to electron absorption thresholds.

Contribution

It provides a detailed analysis of far-infrared reflectance in graphene layers, including the effects of temperature, frequency, and carrier density, and calculates plasmon dispersion with retardation effects.

Findings

Reflectance shows sharp decline at interband absorption threshold.

Multilayer plasmon dispersion includes retardation effects.

Temperature and carrier density significantly influence optical response.

Abstract

We analyze the features of the graphene mono- and multilayer reflectance in the far-infrared region as a function of frequency, temperature, and carrier density taking the intraband conductance and the interband electron absorbtion into account. The dispersion of plasmon mode of the multilayers is calculated using Maxwell's equations with the influence of retardation included. At low temperatures and high electron densities, the reflectance of multilayers as a function of frequency has the sharp downfall and the subsequent deep well due to the threshold of electron interband absorbtion.