Magnetic-field-assisted terahertz quantum cascade laser operating up to 225 K

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Advances in semiconductor bandgap engineering have resulted in the recent development of the terahertz quantum cascade laser1. These compact optoelectronic devices now operate in the frequency range 1.2–5 THz, although cryogenic cooling is still required2,3. Further progress towards the realization of devices operating at higher temperatures and emitting at longer wavelengths (sub-terahertz quantum cascade lasers) is difficult because it requires maintaining a population inversion between closely spaced electronic sub-bands (1 THz ≈ 4 meV). Here, we demonstrate a magnetic-field-assisted quantum cascade laser based on the resonant-phonon design. By applying appropriate electrical bias and strong magnetic fields above 16 T, it is possible to achieve laser emission from a single device over a wide range of frequencies (0.68–3.33 THz). Owing to the suppression of inter-Landau-level non-radiative scattering, the device shows magnetic field assisted laser action at 1 THz at temperatures up to 215 K, and 3 THz lasing up to 225 K.

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Figure 1: Calculated electronic structure.
Figure 2: Optical and electrical characteristics of a terahertz QCL device in a magnetic field.
Figure 3: Laser emission properties as a function of voltage bias.
Figure 4: QCL device performance in terms of spectral coverage and operational temperature.


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The measurements were performed at the National High Magnetic Field Laboratory supported by the National Science Foundation Cooperative Agreement No. DMR-0084173, by the State of Florida, and by the Department of Energy. The work at Massachusetts Institute of Technology is supported by Air Force Office of Scientific Research, National Aeronautics and Space Administration, and National Science Foundation. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

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Correspondence to D. Smirnov.

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Wade, A., Fedorov, G., Smirnov, D. et al. Magnetic-field-assisted terahertz quantum cascade laser operating up to 225 K. Nature Photon 3, 41–45 (2009) doi:10.1038/nphoton.2008.251

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