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Nous présentons une méthodologie de conception, basée sur une modélisation exacte de la diffraction par des réseaux, qui vise à concevoir des réseaux de diffraction qui satisfont aux exigences du piégeage atomique tout en tenant compte des contraintes et des tolérances de fabrication. Nos résultats montrent que des réseaux pertinents peuvent être facilement conçus à l'aide de cette méthode, et nous identifions des conceptions avec des tolérances de fabrication accrues et une meilleure résistance à l'imprécision, ce qui simplifie et augmente les chances de réaliser des pièges atomiques magnéto-optiques à réseaux (GMOTs) efficaces.

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We present a design strategy for grating magneto-optical traps (GMOTs). It takes the three most relevant optical properties for laser cooling (radiation pressure balance, specular reflection cancellation, and diffracted polarization) to build a scalar figure of merit. We use a rigorous coupled wave analysis (RCWA) simulation to find a geometry that maximizes this figure of merit. We also introduce a criterion that takes into account the robustness of the manufacturing processes to select a geometry that is reliable to manufacture. Finally, we demonstrate that the fabricated grating exhibits the expected optical properties and achieves typical GMOT performance.

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We have observed the decoherence of a lithium atomic wave during its propagation in the presence of the radiation emitted by tungsten-halogen lamps, i.e., decoherence induced by blackbody radiation. We used our atom interferometer to detect this decoherence by measuring the atom fringe-visibility loss. The absorption of a photon excites the atom, which spontaneously emits a fluorescence photon. The momenta of these two photons have random directions, and this random character is the main source of decoherence. All previous similar experiments used small-bandwidth coherent excitation by a laser, whereas incoherent radiation involves several technical and conceptual differences. Our approach is interesting as blackbody radiation is omnipresent and decoherence should be considered if particles resonant to electromagnetic fields are used.

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This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions.

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We report here on the realization of light-pulse atom interferometers with large-momentum-transfer atom optics based on a sequence of Bragg transitions. We demonstrate momentum splitting up to 200 photon recoils in an ultracold atom interferometer. We highlight a new mechanism of destructive interference of the losses leading to a sizable efficiency enhancement of the beam splitters. We perform a comprehensive study of parasitic interferometers due to the inherent multiport feature of the quasi-Bragg pulses. Finally, we experimentally verify the phase shift enhancement and characterize the interferometer visibility loss

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Sujets

Electric polarizability Bose Einstein condensate Détecteur à fil chaud Polarisabilité ATOMS Atom interferometry Optique atomique CERN Lab Lithium Bose-Einstein condensate Diode-pumped solid state lasers Axion Atomic polarisability Atom diffraction Aharononov-Bohm Atome de lithium Critical phenomena Accurate measurement Electro-optics Cold atoms Atom Atom optics Diffraction atomique par laser Effet Stark Condensat de Bose-Einstein Mesures de précision Diffraction d'une onde atomique Coherence Black hole Optical pumping Atomic interferometry Polarizability Diffraction Fringevisibility Lithium atoms Ring cavity Diffraction de Bragg Amortissement Cohérence Adsorbats moléculaires Fringe contrast Atomes froids Dark matter Interferometry Compensation Geometric phases Condensats Magneto-optics Matter wave Atom Interferometry Birefringences Phase géométrique Diffraction atomique Experiment Effet Aharonov-Bohm Collisions atome-atome Laser diffraction Vibrations Fringe visibility Non reciprocal effect Experimental results Laser cooling of atoms Aharonov-Bohm He-McKellar-Wilkens Frequency doubling Franges d'interférence Coupled oscillators Aharonov-Casher Damping Decoherence Cosmic string Effet Zeeman Atom chip Zeeman effect Atom interferometers Interférométrie atomique FIELD Condensats de Bose-Einstein Friction Sagnac effect Anisotropy Stark effect Diffraction laser Bragg diffraction Fringe phase shift Atom Optics Aharonov-Bohm effect Atom interferometer Condensates Atom inerteferometry Atomic Bloch states Cooling effect Close-coupling Detector sensitivity Frequency metrology Muonic hydrogen Topological phase CAVITY Parallel velocity Birefringence

Statistiques

Nombre de fichiers déposés

63

Nombre de notices déposées

44