The invention relates to a method for determining a coupling between magnetometers of an array of N magnetometers, for example with optical pumping, where each magnetometer comprises a field cancellation system capable of being activated to operate the magnetometer in zero field. This method comprises a first phase (P1) during which the N magnetometers are separated into N−1 magnetometers whose field cancellation system is deactivated and a measuring magnetometer whose field cancellation system is activated. This first phase comprises: the generation (GENj), by the magnetometers, of a plurality of reference magnetic fields of known amplitudes and distinct directions, the measurement (MESi), by the measuring magnetometer, of the ambient magnetic field on a plurality of measurement axes determination (CALCij) of coupling coefficients between the measuring magnetometer and each of the N magnetometers from said measurement and said known amplitudes.

A parametric resonance magnetometer is provided comprising a cell filled with an atomic gas; an optical pumping source arranged to emit a light beam in a direction of the cell; a polarization device configured so that by the effect of the light beam, the atomic gas simultaneously acquires a state aligned according to an alignment direction and a state oriented according to an orientation direction; a parametric resonance excitation source configured to generate a radiofrequency magnetic field in the cell; and a device to detect parametric resonances and to measure an absorption of the light beam by the atomic gas. The parametric resonance excitation source is configured so that the radiofrequency magnetic field consists of two components orthogonal to one another, each oscillating at its natural oscillation frequency. The two components include a component longitudinal to the orientation direction and a component longitudinal to the alignment direction.

Time-multiplexed atomic magnetometry uses first and second atomic vapor cells to measure an external magnetic field. Each vapor cell operates according to a sequence of alternating pumping and probing stages. However, the sequences are temporally offset from each other such that the second vapor cell is pumped while the first vapor cell is probed, and the first vapor cell is pumped while the second vapor cell is probed. With this time-multiplexed operation, the external magnetic field can be measured without any time gaps. The Hilbert transform of the signals may be taken to obtain their instantaneous phases, which may then be interleaved to form a single gapless time sequence that represents the external magnetic field over a time window that lasts for several continuous pumping/probing stages.

Time-multiplexed atomic magnetometry uses first and second atomic vapor cells to measure an external magnetic field. Each vapor cell operates according to a sequence of alternating pumping and probing stages. However, the sequences are temporally offset from each other such that the second vapor cell is pumped while the first vapor cell is probed, and the first vapor cell is pumped while the second vapor cell is probed. With this time-multiplexed operation, the external magnetic field can be measured without any time gaps. The Hilbert transform of the signals may be taken to obtain their instantaneous phases, which may then be interleaved to form a single gapless time sequence that represents the external magnetic field over a time window that lasts for several continuous pumping/probing stages.

A current-measuring transducer device has a current transducer for measuring an electric current along a conduction path. The current transducer has a magnetic field-sensitive element for converting the magnetic field resulting from the current flow along the conduction path into at least one physical variable and a measuring device for measuring the physical variable. The current transducer device has a coil arrangement with at least one coil for simulating the magnetic field resulting from the current flow along the conduction path. There is also described a method for calibrating a corresponding current transducer and a computer program product for performing the calibration method.

A magnetic field generator includes: an upper layer coil composed of a first conductive material and forming a loop circuit having a coil portion; a lower layer coil composed of a second conductive material and forming a loop circuit having a coil portion arranged opposite to the coil portion of the upper layer coil at a predetermined distance; and a substrate supporting the upper layer coil and the lower layer coil and having a dielectric material between the upper layer coil and the lower layer coil. High-frequency currents of opposite phases are passed through the upper layer coil and the lower layer coil, respectively, and a length per loop of the coil portion in the upper layer coil and the coil portion in the lower layer coil is matched to one wavelength of the high-frequency current.

A magnetic field generator includes: an upper layer coil composed of a first conductive material and forming a loop circuit having a coil portion; a lower layer coil composed of a second conductive material and forming a loop circuit having a coil portion arranged opposite to the coil portion of the upper layer coil at a predetermined distance; and a substrate supporting the upper layer coil and the lower layer coil and having a dielectric material between the upper layer coil and the lower layer coil. High-frequency currents of opposite phases are passed through the upper layer coil and the lower layer coil, respectively, and a length per loop of the coil portion in the upper layer coil and the coil portion in the lower layer coil is matched to one wavelength of the high-frequency current.

An exemplary wearable sensor unit includes 1) a magnetometer comprising a vapor cell comprising an input window and containing an alkali metal, and a light source configured to output light that passes through the input window and into the vapor cell along a transit path, and 2) a temperature control circuit external to the vapor cell and configured to create a temperature gradient within the vapor cell, the temperature gradient configured to concentrate the alkali metal within the vapor cell away from the transit path of the light.

An exemplary wearable sensor unit includes 1) a magnetometer comprising a vapor cell comprising an input window and containing an alkali metal, and a light source configured to output light that passes through the input window and into the vapor cell along a transit path, and 2) a temperature control circuit external to the vapor cell and configured to create a temperature gradient within the vapor cell, the temperature gradient configured to concentrate the alkali metal within the vapor cell away from the transit path of the light.

An optical fiber winding for measuring current circulating through a conductor. The optical fiber winding includes a first helically wound optical fiber cable and a second helically wound optical fiber cable. The first helically wound optical fiber cable is twisted about its longitudinal axis in a first twist direction, and the second helically wound optical fiber cable is twisted about its longitudinal axis in a second twist direction, the first twist direction being opposite the second twist direction. Each of the first and second helically wound optical fiber cables making contact with one another at multiple locations along their length. Due to the first and second helically wound optical fiber cables making contact with one another and being twisted in opposite directions, counteracting forces exist where the first and second helically wound optical fiber cables contact one another to resist an untwisting.