Theory of parametric amplification in in superlattices

TL;DR

This paper presents a theoretical analysis of parametric amplification in superlattices, showing that Bragg reflections induce a resonance enabling phase-sensitive THz amplification without negative differential conductance.

Contribution

It introduces a new theoretical framework for parametric amplification in superlattices, avoiding high-field domain formation.

Findings

Parametric resonance arises from Bragg reflections in minibands.

Phase-sensitive THz amplification is theoretically feasible.

Amplification does not require negative differential conductance.

Abstract

We consider a high-frequency response of electrons in a single miniband of superlattice subject to dc and ac electric fields. We show that Bragg reflections in miniband result in a parametric resonance which is detectable using ac probe field. We establish theoretical feasibility of phase-sensitive THz amplification at the resonance. The parametric amplification does not require operation in conditions of negative differential conductance. This prevents a formation of destructive high-field domains inside the superlattice.