Mid-infrared supermirrors with finesse exceeding 400 000

Author(s)

Gar-Wing Truong, Lukas W. Perner, D. Michelle Bailey, Georg Winkler, Seth B. Cataño-Lopez, Valentin J. Wittwer, Thomas Südmeyer, Catherine Nguyen, David Follman, Adam J. Fleisher, Oliver H. Heckl, Garrett D. Cole

Abstract

For trace gas sensing and precision spectroscopy, optical cavities incorporating low-loss mirrors are indispensable for path length and optical intensity enhancement. Optical interference coatings in the visible and near-infrared (NIR) spectral regions have achieved total optical losses below 2 parts per million (ppm), enabling a cavity finesse in excess of 1 million. However, such advancements have been lacking in the mid-infrared (MIR), despite substantial scientific interest. Here, we demonstrate a significant breakthrough in high-performance MIR mirrors, reporting substrate-transferred single-crystal interference coatings capable of cavity finesse values from 200 000 to 400 000 near 4.5 µm, with excess optical losses (scatter and absorption) below 5 ppm. In a first proof-of-concept demonstration, we achieve the lowest noise-equivalent absorption in a linear cavity ring-down spectrometer normalized by cavity length. This substantial improvement in performance will unlock a rich variety of MIR applications for atmospheric transport and environmental sciences, detection of fugitive emissions, process gas monitoring, breath-gas analysis, and verification of biogenic fuels and plastics.

Organisation(s)

Faculty Center for Nano Structure Research

External organisation(s)

Thorlabs Inc., National Institute of Standards and Technology, Gaithersburg, Université de Neuchâtel

Journal

Nature Communications

Volume

14

No. of pages

8

ISSN

2041-1723

DOI

https://doi.org/10.1038/s41467-023-43367-z

Publication date

11-2023

Peer reviewed

Yes

Austrian Fields of Science 2012

104026 Spectroscopy, 103021 Optics, 103040 Photonics, 205019 Material sciences

ASJC Scopus subject areas

General Physics and Astronomy, General Chemistry, General Biochemistry,Genetics and Molecular Biology

Portal url

https://ucrisportal.univie.ac.at/en/publications/af16b188-86f7-404a-a611-57ee96538981