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

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.

Nanohelices as superlattices: Bloch oscillations and electric dipole transitions

“…Future work will inevitably include a study of the influence of a magnetic field on a superlattice behavior [71] in this helical geometry.…”

Quasiperiodicity and suppression of multistability in nonlinear dynamical systems

“…A key application of semiconductor superlattices is to fill the so-called "THz" gap, i.e., to develop radiation sources, amplifiers and detectors [116][117][118][119][120] from 0.1 to 10 THz, the frequency range in which convenient radiation sources are not readily available [121][122][123][124]. In particular, below 0.1 THz electron transport based devices are typical, and above 10 THz devices based on optical transitions (e.g., solid state lasers) are commonly available.…”

Amplification of electromagnetic radiation in a superlattice placed in a tilted magnetic field

“…To find the current in the system, we use the semiclassical approximation which is based on the Boltzmann equation for electrons in external fields [15]. The superlatice properties in this approach are taken into account by the miniband dispersion relation for the electrons.…”

“…Electron transport in superlattices placed in parallel [2,3] or perpendicular [4][5][6][7][8][9][10][11][12][13] magnetic fields was studied previously. In particular, it was shown recently [15,16] that the magnetic field applied to the superlattice in a direction perpendicular to the axis can shift the maximum on the static current-voltage characteristics (IV curve) towards the region of higher electric field. At the same time, the absorption coefficient can be negative for high frequencies at electric fields corresponding to positive SDC.…”