Quantum cascade (QC) lasers are unipolar devices exploiting optical transitions between engineered electronic states (conduction subbands) created by spatial confinement in semiconductor multi-quantum-wells. The extreme precision of the material growth, necessary to obtain the peculiar characteristics required by the device design, together with the large number of layers and the complexity of the structure, makes this laser the most impressive demonstration of the capabilities offered by bandgap engineering.
After 20 years from their invention, QCLs have reached outstanding performance levels from the mid-IR to the far-infrared spectral ranges. Multi-watt output power, continuous wave, room-temperature devices, with wall-plug efficiencies larger than 50%, actually makes the QCL technology the most efficient one across the mid-IR (4.3-24 µm). At the same time, despite the still low operating temperatures (≤ 199.5 K), THz QCLs gained a realistic chance to deeply impact technological applications, thanks to the high output power (800mW), the quite broad operating frequency range (1.2-4.7 THz), the unmatched compactness and the possibility to engineer the output beam direction via novel plasmonic collimator approaches, as well as to stabilize their frequency, phase and amplitude.
QCL, already commercialized by several key international companies, is nowadays the core photonic component for a large variety of applications spanning from optical chemical sensing in various fields such as security (explosive and narcotics), medical (breath analysis and glucoses monitoring) or environmental to process and quality control, biomedical diagnostic, cultural heritage and telecommunications.
In their 20th year anniversary the workshop will address both the fundamental physics aspect of these devices as well as new outstanding scientific, technological and commercial developments. Top researchers in the field will report on recent exciting advances providing a roadmap for future challenging developments of the powerful QCL technology.
HISTORY
IQCLSW 2014 is the follow-up of a two-years series of very successful meetings:
IQCLSW 2012 took place in Baden, Austria, and was co-chaired by Claire Gmachl (University of Princeton) and Karl Unterrainer (TU Wien)
IQCLSW 2010 took place in Villa Finaly, Florence, Italy, and was co-chaired by Carlo Sirtori (Université Paris Diderot, France) and Gottfried Strasser (TU Wien)
IQCLSW 2008 took place in Monte Verità, Switzerland, and was co-chaired by Jérôme Faist (ETHZ), Alessandro Tredicucci (NEST CNR-INFM), and Claire Gmachl (Princeton University).
The QCL workshop 2006 took place in Brindisi (Italy) and was co-chaired by Qing Hu (MIT) and Gaetano Scamarcio (University of Bari)
The QCL workshop 2004 took place in Seville (Spain) and was co-chaired by Federico Capasso (Harvard University) and Serge Luryi (Stony Brook, USA)