Generation of Slow Surface Plasmon Polaritons in a Complex Waveguide Structure with Electric Current Pump

摘要

A planar spaser structure composed of semiconducting film and graphene with DC current is proposed and theoretically explored. Graphene possesses velocity of drift current carriers comparable with the phase velocity of surface plasmon polaritons (SPPs) in ultrathin semiconducting film at the terahertz regime. When the synchronism condition between current and slow surface electromagnetic waves is realized, the amplification of plasmons by electric current takes place. In the proposed complex waveguide structure, positive feedback is realized due to reflections from the edges of the active waveguide, and the SPPs are decoupled into light by a microscopic grating manufactured on the semiconducting film surface.