Model of the Influence of an External Magnetic Field on the Gain of Terahertz Radiation from Semiconductor Superlattices

TL;DR

This paper presents a theoretical model showing how external magnetic fields can significantly enhance and stabilize terahertz gain in semiconductor superlattices through nonlinear cyclotron oscillations and Stark-cyclotron resonances.

Contribution

It introduces a new theoretical framework for understanding and controlling THz gain in superlattices using magnetic fields, highlighting stability and tunability advantages.

Findings

Large, tunable THz gain due to nonlinear cyclotron oscillations.

Magnetic fields can significantly enhance Bloch gain.

Tilted magnetic fields stabilize gain profiles near Stark-cyclotron resonances.

Abstract

We theoretically analyze the influence of magnetic field on small-signal absorption and gain in a superlattice. We predict a very large and tunable THz gain due to nonlinear cyclotron oscillations in crossed electric and magnetic fields. In contrast to Bloch gain, here the superlattice is in an electrically stable state. We also find that THz Bloch gain can be significantly enhanced with a perpendicular magnetic field. If the magnetic field is tilted with respect to the superlattice axis, the usually unstable Bloch gain profile becomes stable in the vicinity of Stark-cyclotron resonances.