A challenge of bridging the terahertz gap with semiconductor lasers faces an inevitable problem of enhanced non-radiative Auger recombination with reduction of photon energy. We show that this problem can be mitigated in mercury-cadmium-telluride quantum wells (HgCdTe QWs) wherein the Auger process is suppressed due to formation of quasi-relativistic electron-hole dispersion imposing strong energy-momentum restrictions on recombining carriers. Such dispersion is formed upon interaction of topological states at the two QW interfaces. We characterize the lasing properties of HgCdTe QWs quantitatively by constructing a microscopic theory for recombination, absorption, and gain, and show the feasibility of lasing down to ~ 50 μm at liquid nitrogen temperature with threshold currents two orders of magnitude lower than in existing lasers. Our findings comply with recent experimental data on stimulated far-infrared emission from HgCdTe QWs and show the directions toward achievement of maximum possible lasing wavelength.
@article{arxiv.1908.03496,
title = {Fundamental limits to far-infrared lasing in Auger-suppressed HgCdTe quantum wells},
author = {Georgy Alymov and Vladimir Rumyantsev and Sergey Morozov and Vladimir Gavrilenko and Vladimir Aleshkin and Dmitry Svintsov},
journal= {arXiv preprint arXiv:1908.03496},
year = {2019}
}