Abstract-Thermoelectric-cooled terahertz quantum cascade lasers

Martin A. Kainz, Mykhaylo P. Semtsiv, Georgios Tsianos, Sergii Kurlov, W. Ted Masselink, Sebastian Schönhuber, Hermann Detz, Werner Schrenk, Karl Unterrainer, Gottfried Strasser, and Aaron M. Andrews

Fig. 3 THz QCL performance cooled with the thermoelectric cooler. (a) Light-current behaviour in pulsed mode and an operating temperature of 171 K (TEC input: 15 A, 32.1 V). (b) Pulsed and average power of the QCL at different duty cycles. A maximum average power of 120 μW is reached at a duty cycle of 5%.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-27-15-20688

We demonstrate the first lasing emission of a thermo-electrically cooled terahertz quantum cascade laser (THz QCL). A high temperature three-well THz QCL emitting at 3.8 THz is mounted to a novel five-stage thermoelectric cooler reaching a temperature difference of ΔT = 124 K. The temperature and time-dependent laser performance is investigated and shows a peak pulse power of 4.4 mW and a peak average output power of 100 μW for steady-state operation.

Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Abstract-Spectrally resolved far-fields of terahertz quantum cascade lasers

Martin Brandstetter, Sebastian Schönhuber, Michael Krall, Martin A. Kainz, Hermann Detz, Tobias Zederbauer, Aaron M. Andrews, Gottfried Strasser, Karl Unterrainer

(Submitted on 18 Aug 2016)

https://arxiv.org/abs/1608.05257

We demonstrate a convenient and fast method to measure the spectrally resolved far-fields of multimode terahertz quantum cascade lasers by combining a microbolometer focal plane array with an FTIR spectrometer. Far-fields of fundamental TM0 and higher lateral order TM1 modes of multimode Fabry-P\'erot type lasers have been distinguished, which very well fit to the results obtained by a 3D finite-element simulation. Furthermore, multimode random laser cavities have been investigated, analyzing the contribution of each single laser mode to the total far-field. The presented method is thus an important tool to gain in-depth knowledge of the emission properties of multimode laser cavities at terahertz frequencies, which become increasingly important for future sensing applications.

Abstract-InAs based terahertz quantum cascade lasers

Martin Brandstetter^1,a), Martin A. Kainz¹, Tobias Zederbauer²,Michael Krall¹, Sebastian Schönhuber¹, Hermann Detz³, Werner Schrenk², Aaron Maxwell Andrews², Gottfried Strasser² and Karl Unterrainer¹
 HIDE AFFILIATIONS
1 Photonics Institute and Center for Micro- and Nanostructures, Technische Universität Wien, Gusshausstrasse 27-29, 1040 Vienna, Austria
2 Institute for Solid State Electronics and Center for Micro- and Nanostructures, Technische Universität Wien, Floragasse 7, 1040 Vienna, Austria
3 Austrian Academy of Sciences, Dr. Ignaz Seipel-Platz 2, 1010 Vienna, Austria
a) Electronic mail: martin.brandstetter@tuwien.ac.at
Appl. Phys. Lett. 108, 011109 (2016); http://dx.doi.org/10.1063/1.4939551

http://scitation.aip.org/content/aip/journal/apl/108/1/10.1063/1.4939551?TRACK=RSS

We demonstrate terahertz lasing emission from a quantum cascade structure, realized with InAs/AlAs0.16Sb0.84heterostructures. Due to the lower effective electron mass, InAs based active regions are expected to provide a higher optical gain compared to structures consisting of GaAsor InGaAs. The growth by molecular beam epitaxy enabled the fabrication of monolayer-thick barriers, required for the active region, which is based on a 3-well resonantphonon depletion design. Devices were processed in a double-metal waveguide geometry to ensure high mode confinement and low optical losses. Lasing emission at 3.8 THz was observed at liquid helium temperatures by applying a magnetic field perpendicular to the layered structure in order to suppress parasitic scattering channels. These results demonstrate the feasibility of InAs based active regions for terahertz quantum cascade lasers, potentially enabling higher operating temperatures.