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All of you interested in physics are cordially invited!
Physikalisches Kolloquium
Prof. Dr. Jérôme Faist, ETH Zürich, Schweiz:
Terahertz quantum cascade lasers: from single
mode operation to frequency combs
Thursday, 10.11.2016, 17:15, HS 100
Reception with coffee & cookies 16:45
Abstract
The quantum cascade laser[1] has demonstrated the ability to provide gain over a very broad wavelength range, and has seen its
operation wavelength extended to the THz almost 15 years ago[2]. These devices have demonstrated very unique properties in
for high-power and single mode operation, very relevant for applications such as local oscillator sources for radio-astronomy.
These devices take advantage of design features both available in the optical and microwave domain such as extractor antenna
or third-order DFB extractors. We will report on devices that can produce single mode with a very accurate and predictable
frequency and in which the light is coupled out via an array of patch antenna.
We will also focus on recent developments including the demonstration of THz optical frequency combs[3] [4] based on QCL
active regions. The active regions of these devices can extend their gain to more than an octave of bandwidth[4], opening the
possibility of self-referencing and dual-comb spectrosocpy. Recent advances include dual-comb on a single chip, new insights on
the role of dispersion for the comb control, as well as on the possibility of generating very short pulses.
[1] J. Faist, Quantum cascade lasers, 1st ed.: Oxford University Press, 2013.
[2] R. Kohler, A. Tredicucci, F. Beltram, H. Beere, E. Linfield, A. Davies, et al., "Terahertz semiconductor-heterostructure laser," in
Nature vol. 417, ed, 2002, pp. 156-159.
[3] D. Burghoff, T.-Y. Kao, N. Han, C. W. I. Chan, X. Cai, Y. Yang, et al., "Terahertz laser frequency combs," Nature Photonics, vol. 8,
pp. 462-467, Jun 11 2014.
[4] M. Rösch, G. Scalari, M. Beck, and J. Faist, "Octave-spanning semiconductor laser," Nature Photonics, 2015.
[5] J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, " Quantum cascade laser combs", Nanophotonics
(in print) (2016).
Contact: Dr. Guido Fuchs, More Information: uni-kassel.de/go/physikalisches_kolloquium