Plasma excitations of dressed Dirac electrons in graphene layers

Understand

The dispersion relation for the collective plasma excitations of optically dressed Dirac electrons in single and double graphene layers is calculated in the random-phase approximation.

• The presence of circularly polarized light gives rise to an energy gap $E_g$ between the conduction and valence energy bands.
• The value of $E_g$ may be adjusted by varying the frequency and intensity of the light and could be much larger compared to that which is generated by spin-orbit coupling, and may reach values of the gap reported for epitaxially grown graphene.
• We report plasmon dispersion relations for various energy gaps and separation between graphene layers.