Induced by coherent THz-radiation high harmonics generation in bilayer graphene at high Fermi energies

TL;DR

This paper develops a microscopic quantum theory to analyze high harmonic generation in bilayer graphene under high Fermi energies and coherent THz radiation, demonstrating its potential for frequency conversion from THz to mid-IR.

Contribution

The study introduces a nonperturbative quantum model for high harmonic generation in bilayer graphene at high Fermi energies, considering arbitrary polarization of the pump wave.

Findings

Bilayer graphene can generate high-order harmonics from THz to mid-IR frequencies.

The developed theory accurately predicts harmonic rates near the Dirac points.

Bilayer graphene is effective at moderate pump wave intensities for harmonic generation.

Abstract

The higher order harmonic generation process in the nonperturbative regime at the interaction of coherent electromagnetic radiation with the AB-stacked bilayer graphene at high Fermi energies is considered. The applied coherent low-frequency radiation field in the high Fermi energy zone of electrons excludes the interband transitions enhancing high harmonic rates. The developed microscopic nonlinear quantum theory for charged carriers interaction with a strong pump wave is valid near the Dirac points of the Brillouin zone. The Liouville-von Neumann equation for the density matrix in the multiphoton excitation regime is solved both analytically and numerically. Based on the numerical solutions, we examine the rates of higher-order harmonics of the pump wave of arbitrary polarization. Obtained results show that bilayer graphene can serve as an effective material for the generation of higher-order harmonics from THz to the mid-IR domain of frequencies at the pump wave moderate intensities.