Amplification of bulk and surface plasmons in semiconductor superlattices

Abstract

We study the amplification of bulk and surface plasmons in a type II semiconductor superlattice, which consists of a semi-infinite array of spatially separated electron and hole layers. Amplification is achieved by imposing an external drift velocity on the electrons. For drift velocities exceeding a threshold value, bulk plasmons can be amplified for an arbitrary plasmon wave vector parallel to the layers. Amplification of surface plasmons can occur only for finite wave vectors. Drift velocities required for these processes are calculated and are shown to be experimentally feasible.