Chirp control of directional current in monolayer graphene by intense few-cycle laser

TL;DR

This study demonstrates that the residual current in monolayer graphene driven by intense few-cycle laser pulses can be controlled via the initial chirp rate, enabling ultrafast optoelectronic switching.

Contribution

It introduces a method to control current direction in graphene using chirped laser pulses, based on the physical mechanism of chirp-dependent Landau-Zener-St"uckelberg interference.

Findings

Residual current is sensitive to initial chirp rate.

Asymmetry degree follows a sinusoidal function with chirp.

Chirp control enables sub-femtosecond switching in 2D materials.

Abstract

The residual current density in monolayer graphene driven by an intense few-cycle chirped laser pulse is investigated via numerical solution of the time-dependent Schr\"odinger equation. It is found that the residual current is sensitive to the initial chirp rate, and the defined asymmetry degree for current along the different polarization direction versus chirp rate follows a simple sinusoidal function. The underlying physical mechanism is the chirp-dependent Landau-Zener-St\"uckelberg interference. The chirp control of currents provides a novel convenient tool in the petaHertz switching of two-dimensional materials based optoelectronic devices on the sub-femtosecond timescale.