High-Speed Modulation of a Terahertz Quantum Cascade Laser by Coherent Acoustic Phonon Pulses

Abstract

The fast modulation of lasers is a fundamental requirement for applications in optical communications, high-resolution spectroscopy and metrology. In the terahertz-frequency range, the quantum-cascade laser (QCL) is a high-power source with the potential for high-frequency modulation. However, conventional electronic modulation is limited fundamentally by parasitic device impedance, and so alternative physical processes must be exploited to modulate the QCL gain on ultrafast timescales. Here, we demonstrate an alternative mechanism to modulate the emission from a QCL device, whereby optically-generated acoustic phonon pulses are used to perturb the QCL bandstructure, enabling fast amplitude modulation that can be controlled using the QCL drive current or strain pulse amplitude, to a maximum modulation depth of 6% in our experiment. We show that this modulation can be explained using perturbation theory analysis. While the modulation rise-time was limited to ~800 ps by our measurement system, theoretical considerations suggest considerably faster modulation could be possible.

Metadata

Item Type:	Article
Authors/Creators:	Dunn, A https://orcid.org/0000-0002-7369-1469 Poyser, C https://orcid.org/0000-0001-8228-8025 Dean, P https://orcid.org/0000-0002-3950-4359 Demic, A https://orcid.org/0000-0003-1335-6156 Valavanis, A https://orcid.org/0000-0001-5565-0463 Indjin, D https://orcid.org/0000-0002-9121-9846 Salih, M https://orcid.org/0009-0001-6882-4642 Kundu, I https://orcid.org/0000-0002-3564-1903 Li, LH https://orcid.org/0000-0003-4998-7259 Akimov, A https://orcid.org/0000-0002-8173-8212 Davies, AG https://orcid.org/0000-0002-1987-4846 Linfield, EH https://orcid.org/0000-0001-6912-0535 Cunningham, JE https://orcid.org/0000-0002-1805-9743 Kent, A https://orcid.org/0000-0002-2391-6869
Copyright, Publisher and Additional Information:	© The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
Dates:	Accepted: 23 January 2020 Published (online): 11 February 2020 Published: February 2020
Institution:	The University of Leeds
Academic Units:	The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Electronic & Electrical Engineering (Leeds) > Pollard Institute (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds)
Funding Information:	Funder Grant number UK Space Agency Not Known MRC (Medical Research Council) MR/S015833/1 EPSRC EP/M01598X/1 EPSRC EP/P021859/1 EPSRC EP/P001394/1 Royal Society WM150029
Depositing User:	Symplectic Publications
Date Deposited:	28 Jan 2020 11:03
Last Modified:	18 Dec 2024 10:24
Status:	Published
Publisher:	Nature Research
Identification Number:	10.1038/s41467-020-14662-w
Related URLs:	Dataset
Open Archives Initiative ID (OAI ID):	oai:eprints.whiterose.ac.uk:155418