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Broadband phase spectroscopy over turbulent air paths



Fabrizio R. Giorgetta, Greg B. Rieker, Esther Baumann, William C. Swann, Laura C. Sinclair, Jonathan Kofler, Ian R. Coddington, Nathan R. Newbury


Broadband atmospheric phase spectra are measured at sub-milliradian uncertainty corresponding to a 10-13 refractive index change, despite strong decoherence from atmospheric turbulence. A phase-sensitive dual-comb spectrometer acquires spectra over 233 cm-1 covering 70,000 comb teeth and multiple ro-vibrational resonances of CO2, CH4, and H2O. The CO2 concentrations retrieved from a phase and absorbance spectra agree to 0.7 ppm. In general, this system permits high-resolution measurement of the complex susceptibility that is otherwise masked by turbulence in many sensing applications.
Physical Review Letters


atmospheric turbulences, broad band spectroscopy, green house gas, frequency comb


Giorgetta, F. , Rieker, G. , Baumann, E. , Swann, W. , Sinclair, L. , Kofler, J. , Coddington, I. and Newbury, N. (2015), Broadband phase spectroscopy over turbulent air paths, Physical Review Letters, [online],, (Accessed April 15, 2024)
Created September 3, 2015, Updated October 12, 2021