ABSTRACT
In this chapter, the authors propose the concept of terahertz (THz) laser enabled by the resonant electron radiative transitions between graphene layers (GLs) in double-GL structures. They estimate the THz gain for transverse magnetic-mode exhibiting very low Drude absorption in GLs and shows that the gain can exceed the losses in metal-metal waveguides at the low end of the THz range. The authors also propose a device structure based on a double-GL structure with the injection of electrons to one n-doped GL and to another p-doped GL, which can be used for lasing of THz photons with the electric field perpendicular to the GL plane due to the tunneling inter-GL radiative processes. The double-GL structures can also be used in different devices (THz detectors and photomixers) utilizing the plasmonic effects. To enhance the laser output power, a more complex active region can used which includes several double-GL structures or a multiple-GL structure with the tunneling-transparent inter-GL barrier layers.
