Terahertz quantum-cascade lasers

Abstract

Six years after their birth, terahertz quantum-cascade lasers can now deliver milliwatts or more of continuous-wave coherent radiation throughout the terahertz range — the spectral regime between millimetre and infrared wavelengths, which has long resisted development. This paper reviews the state-of-the-art and future prospects for these lasers, including efforts to increase their operating temperatures, deliver higher output powers and emit longer wavelengths.

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Figure 1: Survey of the reported peak performance of terahertz QC lasers.
Figure 2: Conduction-band diagrams for major terahertz QC design schemes.
Figure 3: Terahertz QC-laser waveguides.
Figure 4: Various terahertz cavities.
Figure 5: High-temperature performance.
Figure 6: Terahertz imaging with a QC laser.

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Acknowledgements

I would like to acknowledge G. Scalari, J. Faist, S. Barbieri, A. Dunbar, A. Tredicucci, Q. Hu, A. W. M. Lee, S. Kumar, P. Siegel, and J. R. Gao, who have provided input and/or figures for this article.

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Williams, B. Terahertz quantum-cascade lasers. Nature Photon 1, 517–525 (2007). https://doi.org/10.1038/nphoton.2007.166

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