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Interferometric measurements beyond the coherence length of the laser source

Renaud Matthey-De-L'Endroit, Gaetano Mileti, Florian Gruet, Yves Salvadé, Frank Przygodda, Marcel Rohner, Yves Meyer, Olivier Gloriot, Miguel Llera, Joab Di Francesco & Albert Polster

Résumé Interferometric measurements beyond the coherence length of the laser are investigated theoretically and experimentally in this paper. Thanks to a high-bandwidth detection, high-speed digitizers and a fast digital signal processing, we have demonstrated that the limit of the coherence length can be overcome. Theoretically, the maximal measurable displacement is infinite provided that the sampling rate is sufficiently short to prevent any phase unwrapping error. We could verify experimentally this concept using a miniature interferometer prototype, based on a frequency stabilized vertical cavity surface emitting laser. Displacement measurements at optical path differences up to 36 m could be realized with a relative stability better than 0.1 ppm, although the coherence length estimated from the linewidth and frequency noise measurements do not exceed 6.6 m.
   
Mots-clés
   
Citation R. Matthey-De-L'Endroit, et al., "Interferometric measurements beyond the coherence length of the laser source," Optics Express, vol. 24, p. 21729-21743, Sept. 2016.
   
Type Article de périodique (Anglais)
Date de publication 19-9-2016
Nom du périodique Optics Express
Volume 24
Numéro 19
Pages 21729-21743
URL https://doi.org/10.1364/OE.24.021729