Multiphoton excitation and high harmonic generation in rectangular graphene quantum dot

TL;DR

This paper investigates multiphoton excitation and high harmonic generation in rectangular graphene quantum dots using a quantum theoretical approach, highlighting how size, shape, and edge orientation influence harmonic generation efficiency.

Contribution

Introduces a microscopic quantum model incorporating Hartree-Fock and Hubbard approximations to analyze nonlinear optical processes in RGQDs, emphasizing edge effects.

Findings

Edge orientation significantly affects HHG efficiency.

Larger RGQDs enhance cutoff photon energy.

Shape and size influence harmonic yield.

Abstract

The multiphoton excitation and high harmonic generation (HHG) processes are considered using the microscopic quantum theory of nonlinear interaction of strong coherent electromagnetic (EM) radiation with rectangular graphene quantum dot (RGQD). The dynamic Hartree-Fock approximation is developed for the consideration of the quantum dot-laser field nonlinear interaction at the nonadiabatic multiphoton excitation regime. The many-body Coulomb interaction is described in the extended Hubbard approximation. By numerical results, we show the significance of the RGQD lateral size, shape, and EM wavefield orientation in RGQD of the zigzag edge compear to the armchair edge in the HHG process allowing for increasing the cutoff photon energy and the quantum yield of higher harmonics.