Superluminal light propagation in a monolayer graphene system under external magnetic field

In this paper, we investigated the behaviors of absorptive-dispersive properties of weak polarized probe light in a four-level monolayer graphene nanostructure. Due to the unusual dispersion relation in graphene nanoribbons, electrons can lead to an exceptionally strong optical response in the infrared regions. By using quantum-mechanical density matrix formalism, we obtain the equations of motion that govern the optical response of graphene in strong magnetic and optical fields. It is found that under certain condition and for appropriate choosing the parameters of the medium, the superluminal light propagation in the system is accompanied by amplification to make sure that the probe field is amplified as it passes through the system. Our proposed model may be useful for the next generation of all optical systems and information processing in nanoscale devices.