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arXiv · 1510.09075

Quantum Cascade Laser Frequency Combs

Jérôme Faist·Gustavo Villares·Giacomo Scalari·Markus Rösch·Christopher Bonzon·Andreas Hugi·Mattias Beck
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Abstract

It was recently demonstrated that broadband quantum cascade lasers can operate as frequency combs. As such, they operate under direct electrical pumping at both mid-infrared and THz frequencies, making them very attractive for dual-comb spectroscopy. Performance levels are continuously improving, with average powers over 100 mW and frequency coverage of 100 cm$^{-1}$ in the mid-infrared. In the THz range, 10 mW of average power and 600 GHz of frequency coverage are reported. As a result of the very short upper state lifetime of the gain medium, the mode proliferation in these sources arises from four wave mixing rather than saturable absorption. As a result, their optical output is characterized by the tendency of small intensity modulation of the output power, and the relative phases of the modes to be similar to the ones of a frequency modulated laser. Recent results include the proof of comb operation down to a metrological level, the observation of a Schawlow-Townes broadened linewidth, as well as the first dual-comb spectroscopy measurements. The capability of the structure to integrate monolithically non-linear optical element as well as to operate as a detector show great promise for future chip integration of dual-comb systems.

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Jérôme Faist, Gustavo Villares, Giacomo Scalari, Markus Rösch, Christopher Bonzon, Andreas Hugi, Mattias Beck. 2015-10-30. Quantum Cascade Laser Frequency Combs. https://arxiv.org/abs/1510.09075

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