Scientific Results

A constant intensity technique to improve the performances of devices based on direct absorption spectroscopy

Year: 2015

Authors: Montori A., Depas M., Giuntini M., Siciliani De Cumis M., Viciani S., D’Amato F.

Autors Affiliation: CNR-INO, V.G. Sansone 1, Sesto Fiorentino (FI), 50019, Italy; LENS, University of Florence, V.N. Carrara 1, Sesto Fiorentino (FI), 50019, Italy; CNR-INO, L.go E. Fermi 6, Firenze, 50125, Italy

Abstract: We describe an all-in-fibre apparatus for Constant Intensity Direct Absorption Spectroscopy (CIDAS) for gas concentration measurements which keeps the power of a diode laser constant along the frequency sweep. The reduction of the large variation of the laser power, connected to the frequency scan, enhances the ability of detecting small variations in a background signal, resulting in an increase of the sensitivity with respect to standard direct absorption techniques. Moreover, CIDAS allows for a real-time observation of the absorption signals without any kind of post-detection processing. The apparatus has been tested with carbon dioxide (CO2) and methane (CH4), around 1.57 and 1.65 µm, respectively.

Journal/Review: OPTO-ELECTRONICS REVIEW

Volume: 23 (1)      Pages from: 28  to: 32

More Information: Regione Toscana. – The authors acknowledge the financial support of Regione Toscana, in the frame of ”POR CREO FESR 2007–2013”, Project SIMPAS (Innovative Measurement Systems for the protection of Environment and Health).
KeyWords: Carbon dioxide; Fiber optics; Sensitivity analysis, Applied spectroscopy; Background signals; Constant power; Direct absorption; Direct absorption spectroscopies; Gas concentration measurement; Laser-based; Real time observation, Absorption spectroscopy
DOI: 10.1515/oere-2015-0002

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