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Mid-infrared molecular spectroscopy in the quantum noise limit

Published

Author(s)

David A. Long, Adam J. Fleisher, Qingnan Liu, Joseph T. Hodges

Abstract

A cavity ring-down spectrometer was used to reach the quantum noise limit in the mid-infrared spectral region. Quantum noise was observed not only in the individual ring-down decay events but also in the corresponding ensemble statistics with a magnitude which is commensurate with theoretical predictions. With this instrument a noise-equivalent absorption coefficient of 2.6×10–11 cm–1 Hz–1/2 was demonstrated with less than a microwatt of optical power incident of the photodetector. We believe that this spectrometer’s combination of high sensitivity and robustness make it well suited for measurements of ultra-trace gas species as well as applications in fundamental physics.
Citation
Physical Review Letters
Volume
41
Issue
7

Keywords

Quantum noise, Cavity ring-down spectroscopy, Mid-infrared

Citation

Long, D. , Fleisher, A. , Liu, Q. and Hodges, J. (2016), Mid-infrared molecular spectroscopy in the quantum noise limit, Physical Review Letters, [online], https://doi.org/10.1364/OL.41.001612 (Accessed October 1, 2025)

Issues

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Created March 31, 2016, Updated November 10, 2018
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