Density matrix model for polarons in a terahertz quantum dot cascade laser

Benjamin A. Burnett and Benjamin S. Williams
Phys. Rev. B 90, 155309 – Published 16 October 2014

Abstract

A density matrix based method is introduced for computation of steady-state dynamics in quantum cascade systems of arbitrary size, which incorporates an optical field coherently. The method is applied to a model terahertz quantum dot cascade laser system, where a means of treating coherent electron-optical-phonon coupling is also introduced. Results predict a strong increase in the upper state lifetime and operating temperature as compared to traditional well-based terahertz quantum cascade lasers. However, new complications also arise, including multiple peaks in the gain spectrum due to strong electron-phonon coupling, and strong parasitic subthreshold current channels that arise due to reduced dephasing. It is anticipated that novel design schemes will be necessary for such lasers to become a reality.

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  • Received 25 July 2014
  • Revised 26 September 2014

DOI:https://doi.org/10.1103/PhysRevB.90.155309

©2014 American Physical Society

Authors & Affiliations

Benjamin A. Burnett* and Benjamin S. Williams

  • Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, California 90095, USA

  • *bburnett@ucla.edu

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Issue

Vol. 90, Iss. 15 — 15 October 2014

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