ABSTRACT
This chapter considers the concept of injection terahertz (THz) lasers based on double-graphene-layer (double-GL) structures with metal surface-plasmon waveguide and studies the conditions of their operation. It compares the characteristics of the double-GL lasers with the metal surface-plasmon waveguides with those of such laser with the metal-metal waveguides. The chapter develops a simplified device model of the THz laser exploiting the inter-GL radiative transitions in the double-GL structure with a tunneling barrier layer. GLs are also separated by narrow layers of thickness (about a few nanometers of the same material) from other layers of the structure. The double-GL lasers with the surface plasmon waveguide considered above and the double-GL laser with metal-metal waveguide (with the same lateral sizes) are characterized by similar gain-overlap factors and the THz modal gains. The chapter proposes and substantiates the concept of injection THz lasers based on the double-GL structures supplied by the surface plasmon waveguides and exploiting the inter-GL resonant radiative transitions.
