High resolution dual comb spectroscopy and ranging

Spectroscopy and metrology are amongst the most important applications of electromagnetic fieldsThe very fast oscillations of light (up to 200 THz in the infrared) permit very precise distance measurements as well as broadband analysis of radiations emitted and absorbed by matter.The technologies have evolved tremendously over the years and, at the turn of the century, a ground-breaking technology was proposed.

By using two sources of optical pulse trains (corresponding to optical frequency combs in the spectral domain), no moving parts would be required, and much faster measurements could be performed.

So-called dual comb spectroscopy and ranging have had a very significant impact on their respective fields and have established capabilities in terms of speed and accuracy that are still relevant today.Yet some important limitations remain.

Most importantly, there is a trade-off between resolution an acquisition time which is currently treated as a fundamental limit of dual comb systems.

It prevents these systems from being used for high resolution spectroscopy or long-distance ranging, which are critical for some applications such as gas sensing or large-scale metrology.In HIGHRES, I propose a novel technique which permits overcoming this fundamental limit.

I expect it will improve the current state of the art by as much as three orders of magnitude in terms of resolution (or distance).We will start by a theoretical analysis of the general principle we propose.

We will then build a dual comb source with unprecedented characteristics based on soliton formation in driven fiber resonators.

Finally, using this novel source, we will experimentally demonstrate two proof of principle applications which would greatly benefit from this novel technique, namely THz spectroscopy and very long-distance ranging.