Abstract: A device for measuring the mass flow rate, including a flow pipe; a first set of actuators which are arranged in a first plane including a first transverse cross section of the pipe and perpendicular to the fluid flow path, these being configured to move selectively in the first plane; a control circuit configured to control a movement of the first and second actuators so that the cross-sectional area for flow through the pipe in the first plane remains constant; a measurement sensor measuring a force or a stress in a direction perpendicular to the flow path, in the vicinity of the actuators of the first set along the flow path; a computation device configured to calculate the mass flow rate passing through the flow pipe as a function of the force or stress measured by the sensor.

Abstract: A magneto-optical sensor for sensing a current flowing through a conductor includes a light source capable of providing a linearly-polarised optical beam, and a polarisation analyser configured to perform a differential measurement of two polarisation components of the linearly-polarised optical beam having travelled along an optical path arranged between the light source and the polarisation analyser. The optical path forms a closed trajectory around the conductor. The sensor comprises a cell containing an atomic gas arranged along the optical path.

Abstract: 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.

Abstract: 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.

Abstract: A three-axis vector optically pumped magnetometer includes a cell filled with an atomic gas subjected to an ambient magnetic field the projection of which on three rectangular coordinate axes defines three components thereof, and a photodetector arranged to receive a probe beam that passed through the cell. The photodetector includes a plurality of measurement units arranged in a plane transverse to a direction of propagation of the probe beam, the measurement units each providing a photodetection signal. The magnetometer further comprises a processing unit configured to determine, for each measurement unit and from the photodetection signal, a measurement associated with the measurement unit of each of the three components of the ambient magnetic field; calculate at least one difference between the measurements, associated with different measurement units, of a component of the magnetic field; and deliver a gradiometric measurement signal including the at least one difference calculated.

Abstract: An optical pumping magnetometer made with linearly polarised light. The magnetometer comprises a cell filled with an atomic gas and a detector configured to output a signal carrying information about an alignment state of atoms of the atomic gas in the cell. The magnetometer also comprises a collimator arranged to collimate a light beam before it illuminates the cell and a mirror arranged to reflect the collimated light beam after it has passed through the cell such that the collimated light beam makes a multipass through the cell and illuminates the same region of the cell several times.

Abstract: A parametric resonance magnetometer comprising: a cell filled with an atomic gas; an optical pumping source arranged so as to emit a light beam in the direction of the cell; a polarisation 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 so as to generate a radiofrequency magnetic field in the cell; and a device for detecting parametric resonances configured so as to measure the 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 and each oscillating at its natural oscillation frequency. Said two components comprise a component longitudinal to the orientation direction and a component longitudinal to the alignment direction.

Abstract: A magnetometer is provided which measures an ambient magnetic field having a frequency range of interest. An optical pumping source emits in the direction of a cell filled with an atomic gas a light beam linearly polarised in a polarisation direction. A parametric resonance excitation circuit induces in the cell a radiofrequency magnetic field having two components orthogonal to the polarisation direction and each oscillating at its own oscillation frequency. A parametric resonance detection circuit performs synchronous detection at an inter-harmonic of oscillation frequencies of an electrical signal outputted by a photodetector arranged to receive the light beam having passed through the cell. A zero-field servo-control circuit generates from the synchronous detection a compensation magnetic field opposite to a component of the ambient magnetic field oriented in the polarisation direction.

Abstract: A magneto-optical sensor for sensing a current flowing through a conductor includes a light source capable of providing a linearly-polarised optical beam, and a polarisation analyser configured to perform a differential measurement of two polarisation components of the linearly-polarised optical beam having travelled along an optical path arranged between the light source and the polarisation analyser. The optical path forms a closed trajectory around the conductor. The sensor comprises a cell containing an atomic gas arranged along the optical path.

Abstract: A three-axis vector optically pumped magnetometer includes a cell filled with an atomic gas subjected to an ambient magnetic field the projection of which on three rectangular coordinate axes defines three components thereof, and a photodetector arranged to receive a probe beam that passed through the cell. The photodetector includes a plurality of measurement units arranged in a plane transverse to a direction of propagation of the probe beam, the measurement units each providing a photodetection signal. The magnetometer further comprises a processing unit configured to determine, for each measurement unit and from the photodetection signal, a measurement associated with the measurement unit of each of the three components of the ambient magnetic field; calculate at least one difference between the measurements, associated with different measurement units, of a component of the magnetic field; and deliver a gradiometric measurement signal including the at least one difference calculated.

Abstract: An optical-pumping magnetometer intended to measure an ambient magnetic field.

Abstract: A device for measuring the mass flow rate, including a flow pipe; a first set of actuators which are arranged in a first plane including a first transverse cross section of the pipe and perpendicular to the fluid flow path, these being configured to move selectively in the first plane; a control circuit configured to control a movement of the first and second actuators so that the cross-sectional area for flow through the pipe in the first plane remains constant; a measurement sensor measuring a force or a stress in a direction perpendicular to the flow path, in the vicinity of the actuators of the first set along the flow path; a computation device configured to calculate the mass flow rate passing through the flow pipe as a function of the force or stress measured by the sensor.

Abstract: A vector magnetometer comprising a cell filled with an atomic gas subjected to an ambient magnetic field, an optical pumping source capable of emitting a pump beam tuned to a pumping wavelength towards the cell and a parametric resonance detection device receiving a probe beam that has passed through the cell, the probe beam being identical to or different from the pump beam. The magnetometer also comprises a polarisation device configured so as to simultaneously or alternately confer linear polarisation and circular polarisation to the pump beam emitted towards the cell. And the detection device comprises an optical set up configured to separate, from the probe beam that has passed through the cell, optical signals carrying respectively information about an alignment state of the atoms from information about an orientation state of the atoms.

Abstract: A magnetometer is provided which measures an ambient magnetic field having a frequency range of interest. An optical pumping source emits in the direction of a cell filled with an atomic gas a light beam linearly polarised in a polarisation direction. A parametric resonance excitation circuit induces in the cell a radiofrequency magnetic field having two components orthogonal to the polarisation direction and each oscillating at its own oscillation frequency. A parametric resonance detection circuit performs synchronous detection at an inter-harmonic of oscillation frequencies of an electrical signal outputted by a photodetector arranged to receive the light beam having passed through the cell. A zero-field servo-control circuit generates from the synchronous detection a compensation magnetic field opposite to a component of the ambient magnetic field oriented in the polarisation direction.

Abstract: An optical-pumping magnetometer intended to measure an ambient magnetic field.

Abstract: An optical pumping magnetometer made with linearly polarised light. The magnetometer comprises a cell filled with an atomic gas and a detector configured to output a signal carrying information about an alignment state of atoms of the atomic gas in the cell. The magnetometer also comprises a collimator arranged to collimate a light beam before it illuminates the cell and a mirror arranged to reflect the collimated light beam after it has passed through the cell such that the collimated light beam makes a multipass through the cell and illuminates the same region of the cell several times.

Abstract: A magnetometer that comprises a cell filled with an atomic gas, an optical source and a detector. The source illuminates the cell with a light that has a pump contribution (Fp), that is linearly polarised at least partially and under the effect of which the atoms of the atomic gas undergo an atomic transition, and a probe contribution (Fs), which is linearly polarised and which undergoes variations in polarisation when passing through the cell. The directions of polarisation of the pump contribution and of the probe contribution are collinear orthogonal. The detector takes a differential measurement of the right circular polarisation and of the left circular polarisation of the probe contribution that has passed through the cell.

Abstract: A vector magnetometer comprising a cell filled with an atomic gas subjected to an ambient magnetic field, an optical pumping source capable of emitting a pump beam tuned to a pumping wavelength towards the cell and a parametric resonance detection device receiving a probe beam that has passed through the cell, the probe beam being identical to or different from the pump beam. The magnetometer also comprises a polarisation device configured so as to simultaneously or alternately confer linear polarisation and circular polarisation to the pump beam emitted towards the cell. And the detection device comprises an optical set up configured to separate, from the probe beam that has passed through the cell, optical signals carrying respectively information about an alignment state of the atoms from information about an orientation state of the atoms.

Abstract: The invention relates to the controlling of the wavelength of a laser (2) on an atomic transition. It in particular proposes a method comprising the steps consisting in: emitting a laser beam in the direction of a cell (3) filled with an atomic vapour; carrying out a supply of energy to the atoms of the atomic vapour using a source of energy (4); generating a DAVLL signal (SDAVLL) using the laser beam that has passed through the cell (3); and controlling the wavelength of the laser using the DAVLL signal. According to the invention, the supplying of energy to the atoms of the atomic vapour is modulated to carry out the alternating of a first phase and of a second phase, the first phase supplying more energy than the second phase.

Abstract: The invention relates to the controlling of the wavelength of a laser (2) on an atomic transition. It in particular proposes a method comprising the steps consisting in: emitting a laser beam in the direction of a cell (3) filled with an atomic vapour; carrying out a supply of energy to the atoms of the atomic vapour using a source of energy (4); generating a DAVLL signal (SDAVLL) using the laser beam that has passed through the cell (3); and controlling the wavelength of the laser using the DAVLL signal. According to the invention, the supplying of energy to the atoms of the atomic vapour is modulated to carry out the alternating of a first phase and of a second phase, the first phase supplying more energy than the second phase.