Zbig Wasilewski
Department of Electrical and Computer Engineering, Department of Physics and Astronomy and Waterloo Institute for Nanotechnology, University of Waterloo
Since their initial demonstration in 2002,{Kohler, 2002 #24291} THz QCLs have achieved a remarkable progress and can now operate in 1.2 ‑ 4.5THz spectral range with maximum operating temperatures for the best devices of ∼200K.1 Increasing their operating temperatures to commercially available thermoelectric coolers range (∼240K) will make THz QCLs very attractive to a broad range of potential applications in areas such as biological sensing, pharmaceutical sciences, THz wave imaging, security screening and ICT, to mention just a few. By combining unique to molecular beam epitaxy (MBE) capabilities with theoretical modeling of the THz QCLs we pushed the maximum lasing temperature for these devices to the new world record of 199.5K,1 while the insight gained on the way spurred vigorous activities which led to new promising laser designs. Even though the achieved operating temperatures have already surpassed early expectations, there are no obvious fundamental limits which would prevent THz QCLs from operating right up to room temperature.2 Nevertheless, the present record temperature of 199.5K has remained unchallenged for over three years now, despite intense work by the leading groups around the world. The research program aimed at improving THz QCLs performance targeting two different material systems – arsenides and antimonides – is presently ramping up in our lab.
In this talk, after general introduction, I will give an overview of the state of the art in the field of THz QCL devices, indicate the key roadblocks to achieving higher operating temperatures and discuss possible paths to further improvements.
References:
[1] S. Fathololoumi, E. Dupont, C. W. I. Chan, Z. R. Wasilewski, S. R. Laframboise, D. Ban, A. Mátyás, C. Jirauschek, Q. Hu, and H. C. Liu, Opt. Express 20 (2012) 3866.
[2] Y. Chassagneux, Q. J. Wang, S. P. Khanna, E. Strupiechonski, J.-R. Coudevylle, E. H. Linfield, A. G. Davies, F. Capasso, M. A. Belkin, and R. Colombelli, IEEE Trans. Terahertz Sci.Techn. 2 (2012) 9.
Dr. Wasilewski received his MSc degree in Physics from the University of Warsaw, Poland and subsequently joined the semiconductor physics research group at the Institute of High Pressure Physics, Polish Academy of Sciences. During this period in his career he focused primarily on magneto-optical studies of semiconductors under high hydrostatic pressures. He earned his doctoral degree from the Institute of Physics, Polish Academy of Sciences in 1986. In 1988, after postdoctoral work at the Imperial College in London, where he expanded his research to other material systems and nanostructures, he joined the National Research Council of Canada where he worked until July 2012—since 2006 at the Principal Research Officer level— focusing primarily on the molecular beam epitaxial growth and characterization of quantum structures and devices based on III–V semiconductor compounds. In July 2012 Dr. Wasilewski joined Electrical & Computer Engineering Department at the University of Waterloo as full Professor and Endowed Chair of the Waterloo Institute for Nanotechnology (WIN).