Han, Y orcid.org/0000-0003-2141-3077, Li, LH orcid.org/0000-0003-4998-7259, Zhu, J et al. (7 more authors) (2018) Silver-based surface plasmon waveguide for terahertz quantum cascade lasers. Optics Express, 26 (4). pp. 3815-3827. ISSN 1094-4087
Abstract
Terahertz-frequency quantum cascade lasers (THz QCLs) based on ridge waveguides incorporating silver waveguide layers have been investigated theoretically and experimentally, and compared with traditional gold-based devices. The threshold gain associated with silver-, gold- and copper-based devices, and the effects of titanium adhesion layers and top contact layers, in both surface-plasmon and double-metal waveguide geometries, have been analysed. Our simulations show that silver-based waveguides yield lower losses for THz QCLs across all practical operating temperatures and frequencies. Experimentally, QCLs with silver-based surface-plasmon waveguides were found to exhibit higher operating temperatures and higher output powers compared to those with identical but gold-based waveguides. Specifically, for a three-well resonant phonon active region with a scaled oscillator strength of 0.43 and doping density of 6.83 × 10¹⁵ cm‾³, an increase of 5 K in the maximum operating temperature and 40% increase in the output power were demonstrated. These effects were found to be dependent on the active region design, and greater improvements were observed for QCLs with a larger radiative diagonality. Our results indicate that silver-based waveguide structures could potentially enable THz QCLs to operate at high temperatures.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Editors: |
|
Copyright, Publisher and Additional Information: | Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. |
Keywords: | Semiconductor lasers, quantum cascade; far-infrared lasers |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Electronic & Electrical Engineering (Leeds) |
Funding Information: | Funder Grant number Royal Society WM110032 EPSRC EP/J017671/1 Royal Society WM150029 European Space Agency 4179A EPSRC EP/P021859/1 Centre for Earth Observation Instrumentation Not Known |
Depositing User: | Symplectic Publications |
Date Deposited: | 21 Dec 2017 13:29 |
Last Modified: | 23 Jun 2023 22:41 |
Status: | Published |
Publisher: | Optical Society of America (OSA) |
Identification Number: | 10.1364/OE.26.003814 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:125472 |
Download
Filename: Han et al. - 2018 - Silver-based surface plasmon waveguide for teraher.pdf
Licence: CC-BY 4.0