Dual-comb spectroscopy using plasmon-enhanced-waveguide dispersion-compensated quantum cascade lasers

Jonas Westberg; Lukasz A Sterczewski; Filippos Kapsalidis; Yves Bidaux; Johanna M Wolf; Mattias Beck; Jérôme Faist; Gerard Wysocki

Dual-comb spectroscopy using plasmon-enhanced-waveguide dispersion-compensated quantum cascade lasers

Opt Lett. 2018 Sep 15;43(18):4522-4525.

Authors

Jonas Westberg, Lukasz A Sterczewski, Filippos Kapsalidis, Yves Bidaux, Johanna M Wolf, Mattias Beck, Jérôme Faist, Gerard Wysocki

PMID: 30211906

Abstract

In this Letter, we report on sub-millisecond response time mid-infrared dual-comb spectroscopy using a balanced asymmetric (dispersive) dual-comb setup with a matched pair of plasmon-enhanced-waveguide dispersion-compensated quantum cascade lasers. The system performance is demonstrated by measuring spectra of Bromomethane (CH₃Br) and Freon 134a (CH₂FCF₃) at approximately 7.8 μm. A purely computational phase and timing-correction procedure is used to validate the coherence of the quantum cascade lasers frequency combs and to enable coherent averaging over the time scales investigated. The system achieves a noise-equivalent absorption better than 1×10^-3 Hz^-1/2, with a resolution of 9.8 GHz (0.326 cm^-1) and an optical bandwidth of 1 THz (32 cm^-1), with an average optical power of more than 1 mW per spectral element.