Measurement of the Optical Absorption Spectra of Epitaxial Graphene from Terahertz to Visible

TL;DR

This study measures the optical absorption spectra of epitaxial graphene across a broad frequency range, revealing intraband and interband processes and providing key electronic property insights.

Contribution

It provides comprehensive experimental data on graphene's optical absorption from visible to terahertz frequencies, including carrier densities and scattering times.

Findings

Absorption dominated by intraband processes in THz range

Optical conductivity close to theoretical value in near IR

Extracted carrier densities and scattering times

Abstract

We present experimental results on the optical absorption spectra of epitaxial graphene from the visible to the terahertz (THz) frequency range. In the THz range, the absorption is dominated by intraband processes with a frequency dependence similar to the Drude model. In the near IR range, the absorption is due to interband processes and the measured optical conductivity is close to the theoretical value of $e^{2}/4\hbar$. We extract values for the carrier densities, the number of carbon atom layers, and the intraband scattering times from the measurements.