Martin HAUDEN : "Stables references for a superradiant ytterbium laser"

Abstract : This thesis establishes a solid foundation for the superradiant ultra-stable laser built at FEMTO-ST. The work focuses on the stable references required for the operation of such laser emphasizing two key contribution: a 556 nm laser frequency stabilization to perform a magneto-optical-trap on the intercombination line of 171Yb; and a compact tunable Fabry-Perot cavity, crucial for superradiant lasing. We demonstrate an offset sideband frequency lock of the 556 nm laser using a single electro-optical modulator, covering the frequency gap between the reference iodine vapor cell and 171Yb, and to perform lock-in detection. Sub-Doppler saturated spectroscopy is performed through the vapor, generating an error signal to frequency lock the laser. A characterization setup is implemented with an optical frequency comb, where the 556 nm laser fractional frequency stability is measured to be 1.2×10-11 at one second. Through meticulous estimation of systematic shifts, a few kHz accuracy is obtained. Finally, we propose a low noise tunable compact Fabry-Perot cavity design, suitable for the superradiant lasing in a metrologically relevant regime. A controlled assembly of the cavity is proposed alongside with its ultra-high vacuum system. Subsequently, finesse and frequency stability characterization is performed using a 578 nm laser frequency locked to the resonator with a Poud-Drever-Hall scheme. A finesse of ℱ = 6920 is measured through various techniques while the stability is measured to be 2.2×10-12 at one seconde. Such preliminary results constitute a solid fundation for the superradiant laser

Jury Composition  :

Yann KERSALÉ Professeur - SupMicrotech-ENSMM - Thesis supervisor

Marion DELEHAYE - Chargée de recherche - Université Marie et Louis Pasteur

Jérôme LODEWYCK - Chargé de recherche Université Paris Sciences et Lettres - Observatoire de Paris - Reviewer

Uwe STERR - Senior Scientist Physikalisch-Technische Bundesanstalt (PTB) - Reviewer

Kien PHAN HUY Professeur SupMicrotech ENSMM - Examiner

Sébastien GARCIA Chargé de recherche - Collège de France - Examiner

Localization : SupMicrotech ENSMM 26, rue de l'Épitaphe 25000 BESANÇON
Room: Amphithéâtre Jules Haag