Electric-field effects on multi-photon magneto-optical absorption spectra in two-dimensional graphene: A new approach from the quantum kinetic equation method

In this paper, we perform a detailed theoretical analysis of the multi-photon magneto-optical absorption spectrum and the full width at half-maximum (FWHM) in monolayer graphene under the simultaneous influence of a perpendicular magnetic field and an in-plane electric field. Using the quantum kinetic equation approach, we derive a general expression for the absorption coefficient, incorporating electron–optical phonon interactions, one- and two-photon processes, and both phonon emission and absorption. An electric-field-induced phonon-assisted cyclotron resonance condition is established, explaining the observed blueshift with increasing magnetic field and redshift under stronger electric fields. Notably, the absorption coefficient increases with the magnetic field but decreases with both the electric field and temperature. The FWHM grows linearly with the electric field and approximately as a square-root function of the magnetic field. Both peak positions and the FWHM are nearly temperature-independent. Theoretical results agree well with experiments, highlighting potential applications in graphene-based optoelectronic devices operating under strong fields.