Material-Dependencies of the THz Emission from Plasmonic Graphene-Based Photoconductive Antenna Structures

TL;DR

This paper investigates how the material properties of graphene influence the THz emission capabilities of plasmonic graphene-based photoconductive antennas, highlighting the importance of relaxation time and chemical potential.

Contribution

It provides experimental analysis of graphene materials at THz frequencies and models the dependency of THz emission on intrinsic material parameters.

Findings

THz emission threshold depends on relaxation time and chemical potential.

Experimental characterization of graphene at THz frequencies.

Predictions for material requirements for efficient THz antennas.

Abstract

Graphene supports surface plasmon polaritons with comparatively slow propagation velocities in the THz region, which becomes increasingly interesting for future communication technologies. This ability can be used to realize compact antennas, which are up to two orders of magnitude smaller than their metallic counterparts. For a proper functionality of these antennas some minimum material requirements have to be fulfilled, which are presently difficult to achieve, since the fabrication and transfer technologies for graphene are still evolving. In this work we analyze available graphene materials experimentally and extract intrinsic characteristics at THz frequencies, in order to predict the dependency of the THz signal emission threshold as a function of the graphene relaxation time tau_r and the chemical potential mu_c.