Mid-IR frequency measurement using an optical frequency comb and a long-distance remote frequency reference

Abstract

We have built a frequency chain which enables to measure the absolute frequency of a laser emitting in the 28-31 THz frequency range and stabilized onto a molecular absorption line. The set-up uses an optical frequency comb and an ultrastable 1.55 µm frequency reference signal, transferred from LNE-SYRTE to LPL through an optical link. We are now progressing towards the stabilization of the mid-IR laser via the frequency comb and the extension of this technique to quantum cascade lasers. Such a development is very challenging for ultrahigh resolution molecular spectroscopy and fundamental tests of physics with molecules.I.

Remote Spectral Identification in the THz Band with Reflection Spectroscopy in an Open Atmosphere

“…The subject of using THz radiation in the spectroscopy-based identification of materials was mentioned in [8][9][10]. Although years of research have been dedicated to making improvements in THz techniques, technology puts limitations on the parameters of the available sources and detectors of THz radiation.…”