5 results about "Larmor precession" patented technology

This invention discloses a current measurement and stabilization method based on spin-switched optically pumped nuclear magnetic resonance (NMR). The measurement method includes: connecting the output terminal of the DC current source to be measured to static magnetic field coils located on both sides of an atomic gas cell; applying a high-frequency carrier signal through a lock-in amplifier to apply a static magnetic field and a high-frequency carrier magnetic field to the atomic gas cell; emitting circularly polarized light in the same direction as the static magnetic field to polarize alkali metal atoms and inert gas atoms; applying an alternating magnetic field to the atomic gas cell and emitting linearly polarized light in the same direction as the alternating magnetic field to induce NMR in the polarized inert gas atoms; obtaining the emitted polarized light passing through the atomic gas cell to determine the Larmor precession frequency of the inert gas atoms; and obtaining the output current value of the DC current source to be measured based on the calibrated coil structure constant and the gyromagnetic ratio of the inert gas atoms. This invention utilizes the Larmor precession frequency of the atomic magnetic moments to achieve DC current measurement, exhibiting high measurement accuracy and stability.

This invention provides a calibration system and method for a spin-free exchange-relaxation atomic magnetometer, belonging to the field of precision measurement technology. The calibration system includes: a magnetic field coil configured to generate a square-wave alternating magnetic field within a preset frequency range; an atomic gas chamber configured to provide a polarizable atomic medium, wherein, when the spin-free exchange-relaxation atomic magnetometer is in an unshielded state, the atomic medium undergoes Larmor precession under the influence of the square-wave alternating magnetic field to modulate the probe light of the spin-free exchange-relaxation atomic magnetometer, obtaining an optical modulation signal; a photodetector configured to convert the optical modulation signal into an electrical signal, wherein the electrical signal is used to characterize the amplitude-frequency characteristics corresponding to the frequency range; and a calibration module configured to perform peak detection on the electrical signal and determine the operating state of the spin-free exchange-relaxation atomic magnetometer based on the peak detection result.

The invention relates to the technical field of magnetic field detection, in particular to a magnetic field sensing device and method based on atom ensemble non-Hermite enhancement, and the device comprises an atomic gas chamber which is used for sensing an external magnetic field and generating spin polarization response; the laser pumping and detecting module is used for spreading the pumping light into the atomic gas chamber along the z axis and spreading the detecting light into the atomic gas chamber along the x axis; and the feedback control module is used for measuring the pump light and the probe light in the static magnetic field to obtain a measurement signal, and applying the measurement signal to the electro-optical modulator to form a measurement feedback loop so as to measure the atomic Lamor precession frequency. Therefore, the problems that existing singular point enhanced sensing depends on a multi-resonance mode, manufacturing and coupling are complex and the like are solved.

This invention provides a calibration system and method for a spin-free exchange-relaxation atomic magnetometer, belonging to the field of precision measurement technology. The calibration system includes: a magnetic field coil configured to generate a square-wave alternating magnetic field within a preset frequency range; an atomic gas chamber configured to provide a polarizable atomic medium, wherein, when the spin-free exchange-relaxation atomic magnetometer is in an unshielded state, the atomic medium undergoes Larmor precession under the influence of the square-wave alternating magnetic field to modulate the probe light of the spin-free exchange-relaxation atomic magnetometer, obtaining an optical modulation signal; a photodetector configured to convert the optical modulation signal into an electrical signal, wherein the electrical signal is used to characterize the amplitude-frequency characteristics corresponding to the frequency range; and a calibration module configured to perform peak detection on the electrical signal and determine the operating state of the spin-free exchange-relaxation atomic magnetometer based on the peak detection result.

The invention discloses a rubidium atom magnetometer based on free induction attenuation and a magnetic field measurement method. The magnetometer physical probe comprises a VCSEL laser, an optical shaping unit composed of a convex lens, a polaroid and a 1 / 4 wave plate, a rubidium atom gas chamber, a radio frequency coil assembly and a photoelectric detector. The circuit part comprises a signal conditioning circuit and an oscillation feedback circuit. The method comprises the following steps: working in a periodic pulse mode, firstly starting a laser and radio frequency coil in a period, and performing optical pumping and polarization on rubidium atoms by using left-hand circularly polarized light and a polarized magnetic field along an optical axis; then, the polarized magnetic field is rapidly closed within microsecond magnitude time, so that the atoms spin and freely precession in the external magnetic field to be measured, and an FID signal is generated; after being detected by the photoelectric detector, the signals are fed back to the radio frequency coil through amplification and phase locking processing, and self-oscillation with the frequency locked at the atomic Larmor precession frequency is formed; and measuring the oscillation frequency and calculating the external magnetic field intensity according to the gyromagnetic ratio. The invention has the advantages of high sensitivity, large bandwidth, fast response and small volume.