Frequency accurate coherent electro-optic dual-comb spectroscopy in real-time

Electro-optic dual-comb spectrometers have proved to be a promising technology for sensitive, high-resolution and rapid spectral measurements. Electro-optic combs possess very attractive features like simplicity. reliability, bright optical teeth, and typically moderate but quickly tunable optical spans. Furthermore; in a dual-comb arrangement; narrowband electro-optic combs are generated with a level of mutual coherence that is sufficiently high to enable optical multiheterodyning Without inter-comb stabilization or signal processing systems. However, this valuable tool still presents several limitations, for instance; on most systems; absolute frequency accuracy and long-term stability cannot be guaranteed; likewise; interferometer-induced phase noise restricts coherence time and limits the attainable signal-to-noise ratio. In this paper, We address these drawbacks and demonstrate a cost-efficient absolute electro-optic dual-comb instrument based on a frequency stabilization mechanism and a novel adaptive interferogram acquisition approach devised for electro-optic dual-combs capable of operating in real-time. The spectrometer, completely built from commercial components, provides sub-ppm frequency uncertainties and enables a signal-to-noise ratio of 10000 (intensity) noise) in 30 seconds of integration time. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement