Terahertz gas phase spectroscopy using a high finesse Fabry-P\'erot cavity
Abstract
The achievable instrument sensitivity is a critical parameter for the continued development of THz applications. Techniques such as Cavity-Enhanced Techniques and Cavity Ring Down Spectroscopy have not yet been employed at THz frequency due to the difficulties to construct a high finesse Fabry-P\'erot cavity. Here, we describe such a THz resonator based on a low-loss oversized corrugated waveguide with highly reflective photonic mirrors obtaining a finesse above 3000 around 620 GHz. These components enable a Fabry-Perot THz Absorption Spectrometer with an equivalent interaction length of one kilometer giving access to line intensities as low as 10-27cm- 1/(molecule/cm2) with a S/N ratio of 3. In addition, the intracavity optical power have allowed the Lamb-Dip effect to be studied with a low-power emitter, an absolute frequency accuracy better than 5 kHz can be easily obtained providing an additional solution for rotational spectroscopy.
Keywords
Cite
@article{arxiv.1906.10367,
title = {Terahertz gas phase spectroscopy using a high finesse Fabry-P\'erot cavity},
author = {Francis Hindle and Robin Bocquet and Anastasiia Pienkina and Arnaud Cuisset and Gaël Mouret},
journal= {arXiv preprint arXiv:1906.10367},
year = {2019}
}
Comments
7 pages, 4 figures