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Quantum Cascade Lasers: Current Technology and Future Goals
Published in J Kono, J Léotin, Narrow Gap Semiconductors, 2006
Quantum cascade lasers are steadily increasing their performance in terms of operating temperatures, peak power, average power, and emitting frequency range. The devices become more and more interesting for real world applications. Today, single mode continuous wave operation at room temperature with average power outputs touching 1 Watt is feasible. New design concepts in combination with improved growth as well as processing techniques include MO-CVD, high reflection coating, gold plating, trenching, re-growth, ion implanting, and double metal processing techniques. The understanding of the physics behind the intersubband transitions helps to improve the overall performance of MIR- and THz infrared QCLs. If it will be possible to lower the threshold current densities by introducing quantum dots into the active regions of the devices is still an open question, as well as the invention of new materials to further expand the wavelength range.
Terahertz Imaging and Spectroscopy
Published in Iniewski Krzysztof, Integrated Microsystems, 2017
The most promising terahertz semiconductor lasers are quantum cascade lasers [19,20]. A quantum cascade laser is a unipolar laser, in which the conduction band or the valence band is divided into a few subbands. The carrier transition occurs between these discrete energy levels within the same band. The discrete energy levels are created in a semiconductor heterostructure containing several coupled quantum wells. Quantum cascade lasers with around 10 mW output power at 2 THz have been demonstrated. An operation temperature as high as 93 K has been reported for a terahertz quantum cascade laser at 3.2 THz [21].
Modelling and Simulation
Published in M S Shur, R A Suris, Compound Semiconductors 1996, 2020
The quantum cascade laser is a new mid-infrared laser, based on unipolar transitions of electrons between energy levels created by quantum confinement. Since the first demonstration of QCL (Faist et al. 1994), its design has continuously improved through a series of elegant innovations by the Bell Labs group (Faist et al. 1995a,b) culminating in their recent report of a high power room-temperature operation (Faist et al. 1996).
Frequency stabilisation and SI tracing of mid-infrared quantum-cascade lasers for precision molecular spectroscopy
Published in Molecular Physics, 2022
Mudit Sinhal, Anatoly Johnson, Stefan Willitsch
Precise spectroscopic studies of rovibrational transitions in molecules in the mid-infrared (MIR) frequency domain necessitate the development of accurate, precise, and spectrally narrow MIR lasers. Quantum cascade lasers (QCLs) have proven to be attractive MIR sources capable of operating close to room temperature and emitting intense coherent tunable radiation. Their availability over a wide range of frequencies from 3 to 25 µm has also enabled their use in trace gas sensing [24,25], in free-space MIR optical communications [26,27], and in analytical applications [28].
Approximate analytical expressions for pulse modulation response of quantum cascade lasers
Published in Journal of Modern Optics, 2018
K. S. C. Yong, M. K. Haldar, J. F. Webb
Quantum cascade lasers (QCLs) [1] have shown potential in chemical detection [2] and wireless communication [3]. These are made possible by the abilities of QCLs to provide wide range of wavelengths (from terahertz to mid-infrared) and narrow linewidths. Furthermore, they are favoured as sources for spectroscopy and communication systems because of their compactness, possible integration with drive electronics and room temperature operation unlike other lasers, such as lead salt-based lasers [4].