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Your search keyword '"Gwenael Le Gal"' showing total 4 results
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4 results on '"Gwenael Le Gal"'

1. Zero-field magnetometry based on the combination of atomic orientation and alignment

Author

Gwenael Le Gal and Agustin Palacios-Laloy

Subjects
Atomic Physics (physics.atom-ph), FOS: Physical sciences, Physics::Optics, Physics::Atomic Physics, Physics - Atomic Physics
Abstract

Optically pumped magnetometers usually rely on optical pumping using circularly- or linearly-polarized light. We study here zero-field magnetometers pumped with elliptically-polarized light, preparing both atomic orientation and alignment with complementary geometries. We start by extending the "three-step approach" for elliptically-polarized pumping. This allows us studying the Hanle effect in elliptical polarization by comparing the analytical absorption signals with experiments made on helium-4 metastable state. We then study parametric resonance magnetometers based on elliptical polarization by using the dressed-atom formalism with one and two radio-frequency fields. The results show a good agreement with the experimental measurements and open interesting perspectives for magnetometry where symmetry breaking by pumping light is mitigated.

Published
2021

2. Helium-4 magnetometers for room-temperature biomedical imaging: toward collective operation and photon-noise limited sensitivity

Author

William, Fourcault, Rudy, Romain, Gwenael, Le Gal, François, Bertrand, Vincent, Josselin, Matthieu, Le Prado, Etienne, Labyt, and Agustin, Palacios-Laloy

Subjects
Photons, Optical Phenomena, Optical Imaging, Magnetometry, Temperature, Biosensing Techniques, Equipment Design, Helium
Abstract

Optically-pumped magnetometers constitute a valuable tool for imaging biological magnetic signals without cryogenic cooling. Nowadays, numerous developments are being pursued using alkali-based magnetometers, which have demonstrated excellent sensitivities in the spin-exchange relaxation free (SERF) regime that requires heating to100 °C. In contrast, metastable helium-4 based magnetometers work at any temperature, which allows a direct contact with the scalp, yielding larger signals and a better patient comfort. However former

Published
2021

3. Parametric resonance magnetometer based on elliptically polarized light yielding three-axis measurement with isotropic sensitivity

Author

Gwenael Le Gal, Laure-Line Rouve, Agustin Palacios-Laloy, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Génie Electrique de Grenoble (G2ELab ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)

Subjects
Physics and Astronomy (miscellaneous), Magnetometer, Atomic Physics (physics.atom-ph), FOS: Physical sciences, 02 engineering and technology, Elliptical polarization, 01 natural sciences, law.invention, Physics - Atomic Physics, Optical pumping, Optics, law, 0103 physical sciences, 010302 applied physics, Physics, business.industry, Isotropy, [SPI.NRJ]Engineering Sciences [physics]/Electric power, 021001 nanoscience & nanotechnology, Magnetic field, Amplitude, Radio frequency, Parametric oscillator, 0210 nano-technology, business, Optics (physics.optics), Physics - Optics
Abstract

International audience; We present here a parametric resonance magnetometer scheme based on elliptically polarized pumping light and two radio-frequency fields applied along the two optical pumping directions. At optimum ellipticity and radio-frequency fields amplitudes the three components of the magnetic field are measured with an isotropic sensitivity. Compared to the usual alignment-based parametric resonance magnetometers, the sensitivity is degraded by a factor 2 for two components of the magnetic field but improved by a factor 9 for the third one. The open-loop bandwidth was measured to be greater than 1 kHz for the three axes. This magnetometer configuration could be particularly interesting for geophysics and biomedical imaging.

Published
2020
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4. Dual-Axis Hanle Magnetometer Based on Atomic Alignment with a Single Optical Access

Author

Gaëtan Lieb, Hervé Gilles, Agustin Palacios-Laloy, Thomas Jager, Gwenael Le Gal, François Beato, Département Systèmes (DSYS), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Grenoble Alpes (UGA), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), French National Research Agency ANR Carnot Funding, Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), and Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Physics, Bearing (mechanical), medicine.diagnostic_test, Magnetometer, business.industry, Physics::Medical Physics, General Physics and Astronomy, Magnetoencephalography, Cryogenics, 01 natural sciences, law.invention, Magnetic field, 010309 optics, Optics, law, 0103 physical sciences, Medical imaging, medicine, Physics::Accelerator Physics, Point (geometry), 010306 general physics, business, Beam (structure)
Abstract

Optically pumped magnetometers are serious candidates to replace SQUIDs, and thus avoid the need for cryogenics, in applications like magnetoencephalography. In building magnetometer arrays for imaging, a compact yet multiaxis architecture is highly desirable. Here the authors present a scheme based on atomic alignment that only requires one optical access point, bearing both a pump beam and a probe beam at a small angle to it, and that allows measurement of two magnetic field components. Measuring the third component should be possible via partial depolarization of the pump beam. Such a compact scheme opens interesting perspectives for magnetometer arrays for medical imaging.

Published
2019
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