Recent advances in superlattice frequency multipliers

TL;DR

This paper explores the nonlinear harmonic generation in semiconductor superlattice frequency multipliers, emphasizing the effects of scattering and structural imperfections on their performance for sensing and spectroscopy.

Contribution

It provides a comprehensive theoretical model combining semiclassical Boltzmann and Greens functions approaches to analyze superlattice multipliers under various excitation conditions.

Findings

Elastic scattering significantly affects harmonic generation.

Structural imperfections cause asymmetry in current flow.

The model predicts optimal conditions for radiation output.

Abstract

Semiconductor superlattice multipliers have emerged as a nonlinear medium capable to generate radiation in a wide frequency range. This property facilitates the potential of sources suitable for sensing and spectroscopy applications. In this study, we further investigate the consequences on harmonic generation in a superlattice multiplier after excitation by an input signal oscillating at different frequencies. Here we provide a rigorous description of our theoretical model including a semiclassical Boltzmann approach to nonlinear miniband transport and non-equilibrium Greens functions calculations treating scattering processes under forward and reverse bias. To fully exploit the features of this radiation source, we focus on the effects of elastic scattering and systemat-ic imperfections in the superlattice structure which lead to asymmetric current flow.