title: Iodine Absorption Cells Purity Testing.
abstract: This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions' spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches).
authors.affiliation: Institute of Scientific Instruments of the Czech Academy of Sciences, v.v.i., Královopolská 147, 61264 Brno, Czech Republic. hrabina@isibrno.cz.
authors.forename: Jan
authors.initials: J
authors.lastname: Hrabina
authors.affiliation: National Institute of Metrological Research, Strada delle Cacce 91, 10135 Torino, Italy. m.zucco@inrim.it.
authors.forename: Massimo
authors.initials: M
authors.lastname: Zucco
authors.affiliation: Sytèmes de Référence Temps Espace, SYRTE/CNRS-UMR 8630/LNE/Observatoire de Paris/UPMC, 61, Avenue de l'Observatoire, 75014 Paris, France. charles.philippe@obspm.fr.
authors.forename: Charles
authors.initials: C
authors.lastname: Philippe
authors.affiliation: Institute of Scientific Instruments of the Czech Academy of Sciences, v.v.i., Královopolská 147, 61264 Brno, Czech Republic. tuan@isibrno.cz.
authors.forename: Tuan Minh
authors.initials: TM
authors.lastname: Pham
authors.affiliation: Institute of Scientific Instruments of the Czech Academy of Sciences, v.v.i., Královopolská 147, 61264 Brno, Czech Republic. hola@isibrno.cz.
authors.forename: Miroslava
authors.initials: M
authors.lastname: Holá
authors.affiliation: Sytèmes de Référence Temps Espace, SYRTE/CNRS-UMR 8630/LNE/Observatoire de Paris/UPMC, 61, Avenue de l'Observatoire, 75014 Paris, France. ouali.acef@obspm.fr.
authors.forename: Ouali
authors.initials: O
authors.lastname: Acef
authors.affiliation: Institute of Scientific Instruments of the Czech Academy of Sciences, v.v.i., Královopolská 147, 61264 Brno, Czech Republic. joe@isibrno.cz.
authors.forename: Josef
authors.initials: J
authors.lastname: Lazar
authors.affiliation: Institute of Scientific Instruments of the Czech Academy of Sciences, v.v.i., Královopolská 147, 61264 Brno, Czech Republic. ocip@isibrno.cz.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Číp
keywords: absorption spectroscopy; frequency stability; iodine cells; laser spectroscopy; laser standards