Superluminal electromagnetic two-dimensional plasma waves

We report on a theoretical study of the electromagnetic response of an infinite two-dimensional electron system on a dielectric substrate. We find that electromagnetic radiation incident normal to the substrate surface excites two-dimensional electromagnetic plasma waves with a superluminal character of the spectrum. It is established that there is a strong hybridization between the plasma and the Fabry-Perot light modes. In the presence of a finite magnetic field, the plasma resonance is shown to split into two modes, each corresponding to a particular direction of circular polarization. We discuss the implications of the results for terahertz detection technologies.