We report experimental on-sky observations of atomic spin precession of mesospheric sodium driven by polarization modulation of a continuous-wave laser. A magnetic resonance was remotely detected from the ground by observing the enhancement of induced fluorescence when the driving frequency approached the precession frequency of sodium in the mesosphere, between 85 and 100 km altitude. The experiment was performed at La Palma, and the uncertainty (0.2 kHz) in the measured Larmor frequency (≈260 kHz) corresponded to an error in the geomagnetic field of 0.3 mG. The results are consistent with geomagnetic field models and with the theory of light-atom interaction in the mesosphere.
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http://dx.doi.org/10.1364/OL.43.005825 | DOI Listing |
Eur Phys J C Part Fields
January 2025
Department of Physics, University of Alberta, Edmonton, AB T6G 2E1 Canada.
We analyze the angular momentum balance for a particle undergoing Thomas precession. The relationships among relativistic torque, the center of mass, and the center of inertia for a spinning particle are clarified. We show that spin precession is accompanied by orbital angular momentum precession, and present examples of the resulting out-of-plane motion.
View Article and Find Full Text PDFJ Magn Reson Imaging
January 2025
Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, Jiangsu, China.
Background: At high magnetic fields, degraded image quality due to dielectric artifacts and elevated specific absorption rate (SAR) are two technical challenges in fetal MRI.
Purpose: To assess the potential of high dielectric constant (HDC) pad in increasing image quality and decreasing SAR for 3 T fetal MRI.
Study Type: Prospective.
Nanoscale
January 2025
School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China.
Low-frequency noise in detection systems significantly affects the performance of ultrasensitive and ultracompact spin-exchange relaxation-free atomic magnetometers. High frequency modulation detection helps effectively suppress the 1/ noise and enhance the signal-to-noise ratio, but conventional modulators are bulky and restrict the development of integrated atomic magnetometer modulation-detection systems. Resonant metasurface-based thin-film lithium-niobate (TFLN) active optics can modulate free-space light within a compact configuration.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea.
Magnetization switching by charge current without a magnetic field is essential for device applications and information technology. It generally requires a current-induced out-of-plane spin polarization beyond the capability of conventional ferromagnet/heavy-metal systems, where the current-induced spin polarization aligns in-plane orthogonal to the in-plane charge current and out-of-plane spin current. Here, a new approach is demonstrated for magnetic-field-free switching by fabricating a van-der-Waals magnet and oxide FeGeTe/SrTiO heterostructure.
View Article and Find Full Text PDFNano Lett
January 2025
Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
Realizing field-free switching of perpendicular magnetization by spin-orbit torques is crucial for developing advanced magnetic memory and logic devices. However, existing methods often involve complex designs or hybrid approaches, which complicate fabrication and affect device stability and scalability. Here, we propose a novel approach using -polarized spin currents for deterministic switching of perpendicular magnetization through interfacial engineering.
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