Publication detail

Barrier Height Tuning of Terahertz Quantum Cascade Lasers for High-Temperature Operation

KAINZ, M. SCHÖNHUBER, S. ANDREWS, A. DETZ, H. STRASSER, G. UNTERRAINER, K.

Original Title

Barrier Height Tuning of Terahertz Quantum Cascade Lasers for High-Temperature Operation

English Title

Barrier Height Tuning of Terahertz Quantum Cascade Lasers for High-Temperature Operation

Type

journal article in Web of Science

Language

en

Original Abstract

Terahertz quantum cascade lasers (QCLs) are excellent coherent light sources, but are still limited to an operating temperature below 200 K. To tackle this, we analyze the influence of the barrier height for the identical three-well terahertz QCL layer sequence by comparing different aluminum concentrations (x = 0.12-0.24) in the GaAs/AlxGa1-xAs material system, and then we present an optimized structure based on these findings. Electron injection and extraction mechanisms as well as LO-phonon depopulation processes play crucial roles in the efficient operation of these lasers and are investigated in this study. Experimental results of the barrier height study show the highest operating temperature of 186.5 K for the structure with 21% aluminum barriers, with a record kBTmax/hω value of 1.36 for a three-well active region design. An optimized heterostructure with 21% aluminum concentration and reduced cavity waveguide losses is designed and enables a record operating temperature of 196 K for a 3.8 THz QCL.

English abstract

Terahertz quantum cascade lasers (QCLs) are excellent coherent light sources, but are still limited to an operating temperature below 200 K. To tackle this, we analyze the influence of the barrier height for the identical three-well terahertz QCL layer sequence by comparing different aluminum concentrations (x = 0.12-0.24) in the GaAs/AlxGa1-xAs material system, and then we present an optimized structure based on these findings. Electron injection and extraction mechanisms as well as LO-phonon depopulation processes play crucial roles in the efficient operation of these lasers and are investigated in this study. Experimental results of the barrier height study show the highest operating temperature of 186.5 K for the structure with 21% aluminum barriers, with a record kBTmax/hω value of 1.36 for a three-well active region design. An optimized heterostructure with 21% aluminum concentration and reduced cavity waveguide losses is designed and enables a record operating temperature of 196 K for a 3.8 THz QCL.

Keywords

quantum cascade lasers; terahertz; molecular beam epitaxy; optical phonon; quantized transitions

Released

17.10.2018

Pages from

4687

Pages to

4693

Pages count

7

URL

Documents

BibTex


@article{BUT151466,
  author="Martin A. {Kainz} and Sebastian {Schönhuber} and Aaron Maxwell {Andrews} and Hermann {Detz} and Gottfried {Strasser} and Karl {Unterrainer}",
  title="Barrier Height Tuning of Terahertz Quantum Cascade Lasers for High-Temperature Operation",
  annote="Terahertz quantum cascade lasers (QCLs) are excellent coherent light sources, but are still limited to an operating temperature below 200 K. To tackle this, we analyze the influence of the barrier height for the identical three-well terahertz QCL layer sequence by comparing different aluminum concentrations (x = 0.12-0.24) in the GaAs/AlxGa1-xAs material system, and then we present an optimized structure based on these findings. Electron injection and extraction mechanisms as well as LO-phonon depopulation processes play crucial roles in the efficient operation of these lasers and are investigated in this study. Experimental results of the barrier height study show the highest operating temperature of 186.5 K for the structure with 21% aluminum barriers, with a record kBTmax/hω value of 1.36 for a three-well active region design. An optimized heterostructure with 21% aluminum concentration and reduced cavity waveguide losses is designed and enables a record operating temperature of 196 K for a 3.8 THz QCL.",
  chapter="151466",
  doi="10.1021/acsphotonics.8b01280",
  howpublished="print",
  number="11",
  volume="5",
  year="2018",
  month="october",
  pages="4687--4693",
  type="journal article in Web of Science"
}