CC BY
18LS-I-6
LASER SYSTEMS AND MATERIALS
High-Power Mid-Infrared Quantum-Cascade Lasers
G.S. Sokolovskii
Ioffe Institute, St.Petersburg, Russia gs@mail.ioffe.ru
Quantum-cascade lasers (QCL) attract great attention of the research community since the first publication by Kaza-rinov and Suris proposing the principle in 1971 [1], and especially since the first realization in 1994 by Faist et al. [2]. The main QCL feature distinguishing them from the conventional semiconductor lasers is their unipolarity resulting in the photon emission in the transition of an electron in the conduction band from one quantum level to another instead of recombination of an electron-hole pair. Unfortunately, QCL structures are extremely complicated for practical implementation. The complication comes both from the number of layers that is two orders of magnitude larger than that in a "conventional" semiconductor laser (so-called laser diode) and from the need to maintain the layer homogeneity (i.e., identity of quantum cascades) during long-time epitaxial growth. However, thanks to over quarter of a century efforts of the international research community and over 10 thousand Scopus-indexed publications, QCLs became probably the most efficient sources of coherent radiation in the mid-infrared range, which is well-known for wide atmospheric transparency windows, as well as intense absorption lines of many molecules. Nowadays, mid-infrared QCLs find numerous applications in wireless optical communication, gas analysis, and biomedical research. This report will review the state of the art in mid-infrared QCLs and some practical applications as well as some new results in development of high-power QCLs in this spectral range. Among these results, one should note demonstration of the pulsed output laser power of ~14 W at a wavelength in 4.5 pm region [3], as well as a record-high output power exceeding 16 W achieved in the QCL of the spectral range of 8 pm [4]. In addition, we will discuss very unconventional turn-on dynamics recently revealed in mid-infrared QCLs [5].
This research is supported by the Russian Science Foundation (grant No. 21-72-30020)
[1] R. F. Kazarinov and R.A. Suris, Semiconductors 5, 797 (1971).
[2] J. Faist, et al., Science 264, 553 (1994).
[3] V.V. Dudelev et al., International Conference Laser Optics, St.Petersburg, Russia (2022).
[4] V.V. Dudelev et al., Advanced Photonics Congress, Maastricht, Netherlands (2022).
[5] E.D. Cherotchenko et al., Journal of Lightwave Technology 40(7), 2104-2110 (2022).
ALT'22
