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Intersubband terahertz lasers using four-level asymmetric quantum wells

Kinsler, P., Harrison, P. and Kelsall, R.W. (1999) Intersubband terahertz lasers using four-level asymmetric quantum wells. Journal of Applied Physics, 85 (1). pp. 23-28. ISSN 1089-7550

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We demonstrate the potential for laser operation at far-infrared wavelengths (30–300 µm, 1–10 THz) by using intersubband emission in four-level GaAs/AlGaAs asymmetric (stepped) quantum wells. Achieving population inversion in these devices depends critically on the lifetimes of the nonradiative intersubband transitions, and so we have performed detailed calculations of electron–electron and electron–phonon scattering rates. Our four-subband structures show potential for the realization of room temperature lasing, unlike previously considered three-subband structures which did not give population inversions except at impractically low electron densities and temperatures. Auger-type electron–electron interactions involving the highly populated ground subband effectively destroyed the population inversion in three level systems, but in these four subband structures the inversion is maintained by strong phonon-mediated depopulation of the lower laser level. The largest population inversions are calculated at low temperatures (< 30 K), but for the structures with higher emission energies, room temperature (300 K) operation is also predicted. © 1999 American Institute of Physics.

Item Type: Article
Copyright, Publisher and Additional Information: Copyright © 1999 American Institute of Physics. Reproduced in accordance with the publisher's self-archiving policy. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Institution: The University of Leeds
Academic Units: The University of Leeds > Faculty of Engineering (Leeds) > School of Electronic & Electrical Engineering (Leeds) > Institute of Microwaves and Photonics (Leeds)
Depositing User: Repository Officer
Date Deposited: 01 Nov 2006
Last Modified: 16 Jun 2014 01:43
Published Version: http://dx.doi.org/10.1063/1.369435
Status: Published
Publisher: American Institute of Physics
Refereed: Yes
Identification Number: 10.1063/1.369435
URI: http://eprints.whiterose.ac.uk/id/eprint/1679

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