▎ 摘　　要

High-order harmonic generation is an interesting option to reach the THz range for generation and detection applications. In this work the time-domain and spectral behavior of carrier velocity fluctuations in free-standing graphene under the action of a high frequency alternating electric field are studied by means of an ensemble Monte Carlo simulator. The distortion of the velocity response is explained in terms of the carrier wavevector distribution, average energies and scattering activity. The intensity of the harmonics is analyzed for several frequencies and electric field amplitudes. Noise and regular contributions to the power spectral density of the velocity response are discerned, and the harmonic modes available for several bandwidths are discussed. Results show that it is possible to reach the THz range with conditions comparable to those found for III-V materials, at the expense of narrow bandwidths.