Terahertz quantum cascade lasers operating up to ~ 200 K with optimized oscillator strength and improved injection tunneling
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Hu_Terahertz quantum.pdf
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Author(s)
Fathololoumi, S.
Dupont, E.
Wasilewski, Z. R.
Laframboise, Sylvain R.
Ban, D.
Jirauschek, C.
Liu, H. C.
Chan, Chun Wang Ivan
Hu, Qing
Matyas, A.
Date Issued
February 2012
Journal
Optics Express
Publisher
Optical Society of America
Citation
Fathololoumi, S., E. Dupont, C.W.I. Chan, Z.R. Wasilewski, S.R. Laframboise, D. Ban, A. Matyas, C. Jirauschek, Q. Hu, and H. C. Liu. “Terahertz Quantum Cascade Lasers Operating up to ∼ 200 K with Optimized Oscillator Strength and Improved Injection Tunneling.” Optics Express 20, no. 4 (February 13, 2012): 3866. © 2012 OSA
Version
Final published version
Abstract
A new temperature performance record of 199.5 K for terahertz quantum cascade lasers is achieved by optimizing the lasing transition oscillator strength of the resonant phonon based three-well design. The optimum oscillator strength of 0.58 was found to be larger than that of the previous record (0.41) by Kumar et al. [Appl. Phys. Lett. 94, 131105 (2009)]. The choice of tunneling barrier thicknesses was determined with a simplified density matrix model, which converged towards higher tunneling coupling strengths than previously explored and nearly perfect alignment of the states across the injection and extraction barriers at the design electric field. At 8 K, the device showed a threshold current density of 1 kA/cm[superscript 2], with a peak output power of ~ 38 mW, and lasing frequency blue-shifting from 2.6 THz to 2.85 THz with increasing bias. The wavelength blue-shifted to 3.22 THz closer to the maximum operating temperature of 199.5 K, which corresponds to ~ 1.28ħω/κ[subscript B]. The voltage dependence of laser frequency is related to the Stark effect of two intersubband transitions and is compared with the simulated gain spectra obtained by a Monte Carlo approach.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Research Laboratory of Electronics
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DOI of Published Version
https://doi.org/10.1364/OE.20.003866
