Quantum Cascade Laser Frequency Combs
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 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.
Cite
@article{arxiv.1510.09075,
title = {Quantum Cascade Laser Frequency Combs},
author = {Jérôme Faist and Gustavo Villares and Giacomo Scalari and Markus Rösch and Christopher Bonzon and Andreas Hugi and Mattias Beck},
journal= {arXiv preprint arXiv:1510.09075},
year = {2015}
}