Denis Savoie will defend his thesis on 24th November 2017 at 2 pm on the subject “Continuous and interleaved operation of a cold atom gyroscope and improvement of its stability”, realized at SYRTE laboratory under the direction of Arnaud Landragin and co-supervised by Remi Geiger.

The defense will take place in the main amphitheater of the Institut d’Astrophysique de Paris.

Romain Bouchand will defend his thesis on 21st November 2017 at 4 pm on the subject “Optical frequency comb-based ultralow phase noise photonic microwave generation”, realized at SYRTE laboratory under the direction of Yann Lecoq.

The defense will take place in the main amphitheater of the Institut d’Astrophysique de Paris.

The defense will be in english.

Slawomir Bilicki will defend his thesis on 10th November 2017 at 2 pm on the subject “Strontium optical lattice clocks: clock comparisons for timescales and fundamental physics applications”, realized at SYRTE laboratory under direction of Sébastien Bize and supervised by Jérôme Lodewyck.

The defense will take place in the main amphitheater of the Institut d’Astrophysique de Paris.

The defense will be in english.

Carolina Cárdenas will defend her thesis on 20th october 2017 at Politecnico di Torino (Torino, Italy) on the subject “Digital Instrumentation for the Measurement of High Spectral Purity Signals”. This work has been done in FEMTO-ST Intsitute under the supervision of Enrico Rubiola.

The defense will be in english.

Maxime Favier will defend his thesis on 11th october 2017 at IAP (Paris) at 14:00 on the subject “Mercury optical lattice clock: from high-resolution spectroscopy to frequency ratio measurements”, realized at the SYRTE under the direction of Sébastien Bize and supervised by Sébastien Bize and Luigi De Sarlo.

The defense will take place in room “Salle des séminaires” of the “Institut d’Astrophysique de Paris” (IAP) located 98 bis boulevard Arago, 75014 Paris, in front of a jury composed of Martina Knoop, Leonardo Fallani, Thomas Udem, Philippe Grangier and Jean-Michel Raimond.

The defense will be in english.

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Théo Laudat will defend his thesis on 4th october 2017 at IAP (Paris) at 14:00 on the subject « Spontaneous spin squeezing in a spinor Bose-Einstein condensate trapped on an atom chip ». This work has been done in SYRTE under the supervision of Noel Dimarcq, Peter Rosenbusch, Carlos Garrido Alzar and Jakob Reichel.

The defense will be in english.

ITSNT 2017, symposium on Navigation and Timing : 14-17 Nov 2017 at ENAC (Toulouse, France).

The International Technical Symposium on Navigation and Timing also known as the ITSNT, is an annual event organized by CNES and ENAC for professionals and researchers working with or interested in navigation and timing technologies and their use. This event focuses specifically on technical topics that are addressed by experts from all around the world that share their ideas, expertise and views. The audience can easily engage in discussion with these experts during the question sessions and  round tables. The ITSNT also provides a great environment for networking and visiting our sponsors’ exhibition stands.

Key elements:

• International event
• A high quality and recognized scientific committee
• Technical presentations on hot topics related to navigation and timing
• Internationally recognized guest speakers
• Selective call for abstract
• Round tables
• Exhibition area
• Networking
• Tutorials

http://www.itsnt.fr/en/home/4

Charles PHILIPPE will defense his PhD on the 21st of September, 2017 at IAP (Paris) on the topic “Source laser à 1.5 µm stabilisée en fréquence sur l’iode moléculaire”. This work took place at SYRTE laboratory under the supervision of Ouali ACEF and Peter WOLF.

 

Abstract:

This thesis reports on the development of a frequency stabilization of a 1.54 µm laser diode on iodine hyperfine line at 514 nm, after a frequency tripling process.

An important part of this work is dedicated to the development of the frequency tripling process of a 1.54 µm laser diode, using two periodically polled wave guided Lithium Niobate nonlinear crystals.  A nonlinear conversion efficiency P_3w/P_w > 36 % is obtained. This result is the best efficiency ever demonstrated for a CW frequency tripling process. 300 mW of harmonic power is generated at 514 nm from a fundamental optical power of 800 mW at 1.54 µm. The optical setup is fully fibered. The total power consumption needed to fulfill this frequency tripling process is 20 W only. According a specific operation mode, this laser setup emits simultaneously three frequency-stabilized and intense radiations at 1.54 µm, 771 nm and 514 nm.

Following this development, a very compact laser spectroscopy setup is buildup, based on a short sealed quartz cell, which contains the molecular iodine vapor. An optical power lower than 10 mW in the green is sufficient to fulfill the iodine vapor interrogation, and to detect the hyperfine saturation transitions, whose have a high factor around 514 nm (Q > 2×10⁹).

A frequency stability at the level of 4.5 x 10^-14 t^-1/2 with a minimum value of 6 x 10^-15 from 50 s to 100 s is demonstrated in this study. This frequency stability is the best result ever conferred to a laser diode at 1.54 µm, using in simple way a Doppler-free iodine spectroscopy technique.

This work has allowed to identify the major key components, in order to develop in near future, a fully fibered and compact stabilized laser prototype occupying a total optical volume < 10 liters.

This development could answer to numerous needs of space mission’s projects requiring ultra-stable frequency optical link, inter-satellite or ground to space, for the space geodesy (GRICE), the earth gravitational field measurement (GRACE-FO, NGGM), the gravitational waves detection (LISA) , etc …

 

Keywords: Metrology, frequency stabilization, ultra-stable lasers, Iodine optical clock, nonlinear optic, tripling frequency process, Telecom Laser, 1.5 µm, 514 nm, space.

Dr Tavella is currently a Research Director at the Istituto Nazionale di Ricerca Metrologica (INRIM), responsible for the UTC(IT) Laboratory and the Galileo Timing Research Infrastructure. She is deeply involved in the design and testing of the European GNSS Galileo timing system through more than 30 European projects. Dr Tavella is the previous Chair of the CCTF Working Groups on International Atomic Time (WGTAI) and Algorithms (WG-ALGO).

In addition, Dr Tavella is a Distinguished Lecturer for the Institute of Electrical and Electronics Engineers (IEEE) Ultrasonics, Ferroelectrics and Frequency Control Society (UFFC), a member of the IEEE UFFC Administrative Committee, Vice-Chair of the International Union of Radio Science Commission A (URSI Comm A), and Vice-Chair of the European Frequency and Time Forum (EFTF) Executive Committee.

Dr Tavella has considerable experience of time scales and clock modelling, having conceived, designed, and developed, in collaboration with different colleagues, several methods and techniques for the time scale definition and measurement data treatment. These include possible uses and drawbacks of the Kalman filter in the ensemble time scale; contribution to the ensemble algorithm for a pulsar time scale; and the application of stochastic processes to model the atomic clock deviation and survival time within error thresholds, applied also to the determination of calibration interval.

Official announcement: http://www.bipm.org/en/news/full-stories/2017-06/2017-07-new-directors.html.