Electrons performing Bloch oscillations in an energy band of a dc-biased superlattice in the presence of weak dissipation can potentially generate THz fields at room temperature. The realization of such Bloch oscillator is a long-standing problem due to the instability of a homogeneous electric field in conditions of negative differential conductivity. We establish the theoretical feasibility of stable THz gain in a long superlattice device in which the bias is quasistatically modulated by microwave fields. The modulation waveforms must have at least two harmonics in their spectra.
@article{arxiv.0812.4046,
title = {Terahertz Bloch oscillator with a modulated bias},
author = {Timo Hyart and Natalia V. Alexeeva and Jussi Mattas and Kirill N. Alekseev},
journal= {arXiv preprint arXiv:0812.4046},
year = {2009}
}