@article{728446e2ceea4c2da78f2e01498384ae,
title = "Origin of terminal voltage variations due to self-mixing in terahertz frequency quantum cascade lasers",
abstract = "We explain the origin of voltage variations due to self-mixing in a terahertz (THz) frequency quantum cascade laser (QCL) using an extended density matrix (DM) approach. Our DM model allows calculation of both the current-voltage (I-V) and optical power characteristics of the QCL under optical feedback by changing the cavity loss, to which the gain of the active region is clamped. The variation of intra-cavity field strength necessary to achieve gain clamping, and the corresponding change in bias required to maintain a constant current density through the heterostructure is then calculated. Strong enhancement of the self-mixing voltage signal due to non-linearity of the (I-V) characteristics is predicted and confirmed experimentally in an exemplar 2.6 THz bound-to-continuum QCL.",
keywords = "Mixing, Quantum cascade lasers, quantum cascade laser (QCL)",
author = "Andrew Grier and Paul Dean and Alexander Valavanis and James Keeley and Iman Kundu and Cooper, {Jonathan D.} and Gary Agnew and Thomas Taimre and Lim, {Yah Leng} and Karl Bertling and Raki{\'c}, {Aleksandar D.} and Li, {Lianhe H.} and Paul Harrison and Linfield, {Edmund H.} and Zoran Ikoni{\'c} and Davies, {A. Giles} and Dragan Indjin",
note = "Funding Information: This work was supported by Engineering and Physical Sciences Research Council (EPSRC) Grant COTS (EP/J017671/1); the Royal Society (UF130493) and the Royal Society Wolfson Research Merit Award scheme (A.G.D., E.H.L.)(UF130493); European Cooperation in Science and Technology (COST) (BM1205 and MP1204); and the Australian Research Council (DP160103910). A.G. acknowledges support from an EPSRC DTG award. P.D. acknowledges support from the EPSRC Fellowship scheme (EP/J002356/1). Y.L.L. acknowledges support under the Queensland Government's Advance Queensland programme. Data associated with this paper are openly available from the University of Leeds data repository: http://doi.org/10.5518/77. Publisher Copyright: {\textcopyright} 2016, OSA - The Optical Society. All rights reserved.",
year = "2016",
month = sep,
day = "19",
doi = "10.1364/OE.24.021948",
language = "English",
volume = "24",
pages = "21948--21956",
journal = "Optics Express",
issn = "1094-4087",
publisher = "The Optical Society",
number = "19",
}