High resolution dual comb spectroscopy and ranging

Introduction

Spectroscopy and metrology are amongst the most important applications of electromagnetic fields. The 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.

Technological Evolution

The technologies have evolved tremendously over the years. 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.

Limitations of Current Systems

Yet some important limitations remain. Most importantly, there is a trade-off between resolution and acquisition time, which is currently treated as a fundamental limit of dual comb systems. This limitation prevents these systems from being used for:

1. High-resolution spectroscopy
2. Long-distance ranging

These applications are critical for some fields, such as gas sensing or large-scale metrology.

Proposed Solution

In HIGHRES, I propose a novel technique that 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).

Project Plan

We will start with a theoretical analysis of the general principle we propose.

Next, we will 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 that would greatly benefit from this novel technique, namely:

1. THz spectroscopy
2. Very long-distance ranging