Molecular gas sensing below parts per trillion: radiocarbon-dioxide optical detection
Authors: Galli I., Bartalini S., Borri S., Cancio P., Mazzotti D., De Natale P., Giusfredi G.
Autors Affiliation: Istituto Nazionale di Ottica CNR, I-50019 Sesto Fiorentino, Italy; European Laboratory for Non-Linear Spectroscopy (LENS), I-50019 Sesto Fiorentino, Italy
Abstract: Radiocarbon ((14)C) concentrations at a 43 parts-per-quadrillion level are measured by using saturated-absorption cavity ringdown spectroscopy by exciting radiocarbon-dioxide ((14)C(16)O(2)) molecules at the 4.5 mu m wavelength. The ultimate sensitivity limits of molecular trace gas sensing are pushed down to attobar pressures using a comb-assisted absorption spectroscopy setup. Such a result represents the lowest pressure ever detected for a gas of simple molecules. The unique sensitivity, the wide dynamic range, the compactness, and the relatively low cost of this table-top setup open new perspectives for (14)C-tracing applications, such as radiocarbon dating, biomedicine, or environmental and earth sciences. The detection of other very rare molecules can be pursued as well thanks to the wide and continuous mid-IR spectral coverage of the described setup.
Journal/Review: PHYSICAL REVIEW LETTERS
Volume: 107 (27) Pages from: 270802 to: 270802
More Information: We thank V. Perevalov, V.E. Zuev Institute of Atmospheric Optics-Russian Academy of Science, for calculating molecular data and M. Fedi, University of Firenze and INFN, for discussions about AMS dating. We gratefully acknowledge Michele Giusfredi for his support in the 2010 CO