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-Enhanced Crystal Quality of AlxIn1-xAsySb1-y for Terahertz Quantum Cascade Lasers

Tobias Zederbauer 1,* , Aaron Maxwell Andrews 1

, Donald MacFarland 1

, Hermann Detz 2

,Werner Schrenk 3

 and Gottfried Strasser 1,3

1 TU Wien, Institude of Solid State Electronics, Floragasse 7, 1040 Wien, Austria2 Austrian Academy of Sciences, Dr. Ignaz Seipel-Platz 2, 1010 Wien, Austria3 TU Wien, Center for Micro and Nano Structures, Floragasse 7, 1040 Wien, Austria

* Author to whom correspondence should be addressed.

Received: 31 March 2016 / Revised: 14 April 2016 / Accepted: 15 April 2016 / Published: 20 April 2016

(This article belongs to the Special Issue Quantum Cascade Lasers - Advances and New Applications)

http://www.mdpi.com/2304-6732/3/2/20

View Full-Text   |   Download PDF [4558 KB, uploaded 20 April 2016]   |    Browse Figures 

This work provides a detailed study on the growth of AlxIn1-xAsySb1-y lattice-matched to InAs by Molecular Beam Epitaxy. In order to find the conditions which lead to high crystal quality deep within the miscibility gap, AlxIn1-xAsySb1-y with x = 0.462 was grown at different growth temperatures as well as As2 and Sb2 beam equivalent pressures. The crystal quality of the grown layers was examined by high-resolution X-ray diffraction and atomic force microscopy. It was found that the incorporation of Sb into Al0.462In0.538AsySb1-y is strongly temperature-dependent and reduced growth temperatures are necessary in order to achieve significant Sb mole fractions in the grown layers. At 480 ∘C$$ lattice matching to InAs could not be achieved. At 410 ∘C$$ lattice matching was possible and high quality films of Al0.462In0.538AsySb1-y were obtained.

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.

Abstract-Coupled cavity terahertz quantum cascade lasers with integrated emission monitoring

Coupled cavity terahertz quantum cascade lasers with integrated emission monitoring Michael Krall, Michael Martl, Dominic Bachmann, Christoph Deutsch, Aaron M. Andrews, Werner Schrenk, Gottfried Strasser, and Karl Unterrainer  »View Author Affiliations

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-23-3-3581

Optics Express, Vol. 23, Issue 3, pp. 3581-3588 (2015)
http://dx.doi.org/10.1364/OE.23.003581

View Full Text Article

Enhanced HTML    Acrobat PDF (1567 KB)

We demonstrate the on-chip generation and detection of terahertz radiation in coupled cavity systems using a single semiconductor heterostructure. Multiple sections of a terahertz quantum cascade laser structure in a double-metal waveguide are optically coupled and operate either as a laser or an integrated emission monitor. A detailed analysis of the photon-assisted carrier transport in the active region below threshold reveals the detection mechanism for photons emitted by the very same structure above threshold. Configurations with a single laser cavity and two coupled laser cavities are studied. It is shown that the integrated detector can be used for spatial sensing of the light intensity within a coupled cavity.

© 2015 Optical Society of America

Abstract-Subwavelength micropillar array terahertz lasers

Michael Krall, Martin Brandstetter, Christoph Deutsch, Hermann Detz, Aaron Maxwell Andrews, Werner Schrenk, Gottfried Strasser, and Karl Unterrainer  »View Author Affiliations

We report on micropillar-based terahertz lasers with active pillars that are much smaller than the emission wavelength. These micropillar array lasers correspond to scaled-down band-edge photonic crystal lasers forming an active photonic metamaterial. In contrast to photonic crystal lasers which use significantly larger pillar structures, lasing emission is not observed close to high-symmetry points in the photonic band diagram, but in the effective medium regime. We measure stimulated emission at 4 THz for micropillar array lasers with pillar diameters of 5 µm. Our results not only demonstrate the integration of active subwavelength optics in a terahertz laser, but are also an important step towards the realization of nanowire-based terahertz lasers.

© 2014 Optical Society of America

Abstract-Influence of the facet type on the performance of terahertz quantum cascade lasers with double-metal waveguides

Werner Schrenk², Gottfried Strasser²,  Karl Unterrainer¹
Martin Brandstetter¹, Michael Krall¹, Christoph Deutsch¹, Hermann Detz², Aaron M. Andrews²,

¹Photonics Institute and Center for Micro- and Nanostructures, Vienna University of Technology, Gusshausstrasse 29, A-1040 Vienna, Austria
²Institute of Solid-State Electronics and Center for Micro- and Nanostructures, Vienna University of Technology, Floragasse 7, A-1040 Vienna, Austria 

http://apl.aip.org/resource/1/applab/v102/i23/p231121_s1?isAuthorized=no

We investigate the influence of cleaved and dry chemically etched facets on the performance of terahertz quantum cascade lasers with double-metal waveguides. We theoretically show that the reflectivity and therefore also the mirror losses depend on the facet type. We fabricated devices employing both a cleaved and an etched facet, which show an asymmetric output characteristic. Furthermore, we compare the performance in terms of maximum operation temperature of lasers with each facet configuration. The results suggest that the devices are operated in a mirror loss dominated regime.

© 2013 © 2013 Author(s).