PHARAO laser source flight model: Design and performances

Lévèque, Thomas; Faure, Benoît; Esnault, François Xavier; Delaroche, C.; Massonnet, D.; Grosjean, Olivier; Buffe, Fabrice; Torresi, Patrizia; Bömer, Thomas; Pichon, Alexis Le; Béraud, P.; Lelay, Jean Pierre; Thomin, S.; Laurent, Ph.

doi:10.1063/1.4914025

Cited by 44 publications

(27 citation statements)

References 13 publications

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“…The operation of the laser source is controlled by the computer to run the successive phases of atomic manipulation during one clock cycle: capture, launch, cooling, atomic cloud slicing, state selection, and detection. A specificity of the laser source is the high level of compactness and integration with hundreds of optical components and thousands of screws enabling optical alignment stability after space qualifications, vibrations at 100 m/s 2 and temperature cycling from −40, to +40 • C. Important parameters of the laser source are the laser power to load a large number of cold atoms, a low relative intensity noise and low phase noise to reach the lowest atomic temperature and to detect the atoms with high signal-to-noise ratio, contributing to the clock short-term stability [29]. …”

Section: Laser Sourcementioning

confidence: 99%

The ACES/PHARAO space mission

Laurent

Massonnet

Cacciapuoti

et al. 2015

Comptes Rendus. Physique

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Section: Laser Sourcementioning

confidence: 99%

The ACES/PHARAO space mission

Laurent

Massonnet

Cacciapuoti

et al. 2015

Comptes Rendus. Physique

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“…The thermal stability exhibited in this work is comparable with the one achieved in other approaches, like the one in MAUIS [16], where CE between 85% and 92% was achieved, with the comparable advantage of ease of manufacturing and implementation design, while keeping the whole design stable by incorporating monolithic designs. The 0.2% RMS stability of CE in stable temperature condition is an indirect measurement of the angular stability of the beam that can be calculated to be better than 10 µrad and is comparable to the one achieved using active stabilization in PHARAO laser system [13]. Future work aims to assess the performance of the breadboard at the presence of vibrations and proceed to a full subsystem based on OBST that will include active optical elements such as acousto-optic modulators and beam shutters.…”

Section: Discussionmentioning

confidence: 91%

Precise and robust optical beam steering for space optical instrumentation

et al. 2019

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This approach permits much finer adjustments of the beam direction and position when compared to other beam steering techniques of the same mechanical precision. This results in a much increased precision, accuracy and mechanical stability. A precision of better than 5 µrad and 5 µm is demonstrated, resulting in a resolution in coupling efficiency of 0.1%. Together with the added flexibility of an additional beam steering element, this allows a great simplification of the design of the fiber coupler, which normally is the most complex and sensitive element on an optical fiber breadboard. We demonstrate a fiber to fiber coupling efficiency of more than 89.8%, with a stability of 0.2% in a stable temperature environment and 2% fluctuations over a temperature range from 10°C to 40°C over a measurement time of 2 G. Drougakis et al.14 hours. Furthermore, we do not observe any non-reversible change in the coupling efficiency after performing a series of tests over large temperature variations. This technique finds direct application in proposed missions for quantum experiments in space [1, 2, 3], e.g. where laser beams are used to cool and manipulate atomic clouds. IntroductionActive optics play a rapidly increasing role in space instrumentation, for example in satellite systems that have started to use LIDAR [4,5,6,7], optical communication [8], and laser ranging [9,10].Space-based quantum technologies and atom clocks rely on an intricate manipulation of a number of ultra-stable laser sources leading to highly complex optical signal conditioning setups, which can be problematic for space missions. In some cases, this can be handled by in-fiber devices, more often, however, the requirements exceed what can be achieved in single mode waveguide devices and optical benches handling fiber to free-space to fiber coupling are required. Examples include cases where precise frequency shifting (acoustooptic modulators) or very high extinction ratios are needed, such as proposals for cold atom experiments in space [11,12]. Many components require single mode fiber to fiber coupling resulting in very stringent requirements in alignment and stability of the optical breadboard and its components. To meet these requirements, the PHARAO cold atom clock designed for space application [13] needed to incorporate active stabilization of many optical components like the mirrors used to inject light into fibers. For the LISA Pathfinder and LISA candidate systems [14,15] the optical components were attached to the breadboard using hydroxyl bonding to achieve high stability standards, albeit at the cost of extreme requirements on the manufacturing process. Another approach used in MAIUS1 mission using a combination of different types adhesives and complex moving parts to steer the beam with high precision [16,17].In this paper, we report on a novel optical beam steering technique (OBST) for fiber to free-space to fiber coupling breadboards. We achieve robust, ultrastable and yet extremely fine beam steering using simple optical elements, lik...

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“…Let us take the atomic clocks [43,44] in gravitational red shift experiments [28,45] and Bose-Einstein condensates in free-falling experiments [37] as typical examples concerning quantum systems in gravitational fields, compared to the curvature radius the corresponding quantum systems or wave packets are viewed as being sharply peaked at or bounded to some small space regions. It is assumed that such quantum systems are evolved according to the proper time of the co-moving frame attached to the mass center of the experimental platform.…”

Section: Quantum Wave Packets In Weakly Curved Spacetimementioning

confidence: 99%

De Broglie relations, gravitational time dilation and weak equivalence principle

Qiang

2019

Annals of Physics

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Interplays between quantum physics and gravity have long inspired exciting studies, which reveal subtle connections between quantum laws and the general notion of curved spacetime. One important example is the uniqueness of free-falling motions in both quantum and gravitational physics. In this work, we re-investigate the freefalling motions of quantum test wave packets that are distributed over weakly curved spacetime backgrounds. Except for the de Broglie relations, no assumption of priori given Hamiltonians or least actions satisfied by the quantum system is made. We find that the mean motions of quantum test wave packets can be deduced naturally from the de Broglie relations with a generalized treatment of gravitational time dilations in quantum waves. Such mean motions of quantum test masses in gravitational field are independent of their masses and compositions, and restore exactly the free-falling or geodesic motions of classical test masses in curved spacetime. This suggests a novel perspective that weak equivalence principle, which states the universality of free-fall, may be deeply rooted in quantum physics and be a phenomenon that has emerged from the quantum world.

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PHARAO laser source flight model: Design and performances

Cited by 44 publications

References 13 publications

The ACES/PHARAO space mission

The ACES/PHARAO space mission

Precise and robust optical beam steering for space optical instrumentation

De Broglie relations, gravitational time dilation and weak equivalence principle

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