@ARTICLE{Montori_A._A_2015, author={Montori, A. and Pas de, M. and Giuntini, M. and Siciliani Cumis de, M. and Viciani, S. and D’Amato, F.}, volume={vol. 23}, number={No 1}, journal={Opto-Electronics Review}, pages={28-32}, howpublished={online}, year={2015}, publisher={Polish Academy of Sciences (under the auspices of the Committee on Electronics and Telecommunication) and Association of Polish Electrical Engineers in cooperation with Military University of Technology}, 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.}, type={Article}, title={A constant intensity technique to improve the performances of devices based on direct absorption spectroscopy}, URL={http://journals.pan.pl/Content/116116/PDF/opelre_2015_3.pdf}, keywords={Applied spectroscopy, laser based detection, direct absorption, constant power intensity, fibre optics}, }