Ultrafast terahertz responses in monolayer graphene

TL;DR

This paper provides a theoretical analysis of monolayer graphene's ultrafast terahertz responses, revealing its large nonlinear optical behavior and potential for ultrafast THz applications.

Contribution

It introduces analytical formulations of photon carrier, polarization, and current in graphene under ultrafast THz pulses, aligning with recent experimental results.

Findings

Photon carrier density increases with THz frequency

Electric polarization and current density grow with frequency

Graphene exhibits significant nonlinear ultrafast THz responses

Abstract

We theoretically investigate the ultrafast terahertz(THz) properties of monolayer graphene. The analytical formulations of the photon carrier, electric polarization and optical current are obtained by solving the Bloch-equations in present of the ultrafast THz Gaussian pulse. Graphene shows a large nonlinear and ultrafast optical response at THz frequencies due to the gapless and relativistic Dirac particles with nearly linear energy dispersion. It is found that the photon carrier density, electric polarization and optical current density increase with increasing the frequency of the THz pulse. These theoretical results are in agreement with recent experimental findings. This study confirms further that graphene exhibits important features and is relevant to the applications in the ultrafast THz fields.