2014/01/01 by Gregory B. Rieker, Rieker, Gregory B., Fabrizio R. Giorgetta +23 · 3 citations
Chemistry · Earth and Planetary Sciences · Engineering · Environmental Science · Physics and Astronomy · #Advanced Chemical Sensor Technologies #Advanced Fiber Laser Technologies #Atmospheric Ozone and Climate #Atmospheric and Environmental Gas Dynamics #FOS: Physical sciences #Optics (physics.optics) #Spectroscopy and Laser Applications
paper · pdf · doi:10.48550/arxiv.1406.3326
openalex publication_date 2014/06/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We demonstrate coherent dual frequency-comb spectroscopy for detecting\nvariations in greenhouse gases. High signal-to-noise spectra are acquired\nspanning 5990 to 6260 cm-1 (1600 to 1670 nm) covering ~700 absorption features\nfrom CO2, CH4, H2O, HDO, and 13CO2, across a 2-km open-air path. The\ntransmission of each frequency comb tooth is resolved, leading to spectra with\n<1 kHz frequency accuracy, no instrument lineshape, and a 0.0033-cm-1 point\nspacing. The fitted path-averaged concentrations and temperature yield dry-air\nmole fractions. These are compared with a point sensor under well-mixed\nconditions to evaluate current absorption models for real atmospheres. In\nheterogeneous conditions, time-resolved data demonstrate tracking of strong\nvariations in mole fractions. A precision of <1 ppm for CO2 and <3 ppb for CH4\nis achieved in 5 minutes in this initial demonstration. Future portable systems\ncould support regional emissions monitoring and validation of the spectral\ndatabases critical to global satellite-based trace gas monitoring.\n