11 results about "Larmor precession" patented technology

The invention discloses an SERF atom magnetometer double-axis magnetic field detection method and device based on pulsed magnetic field modulation, relates to the technical field of magnetic field precision measurement, and compresses the action time of a modulation magnetic field additionally applied in the same unit period on a hot atom ensemble by replacing conventional continuous sinusoidal magnetic field modulation with pulsed magnetic field modulation. The pulse magnetic field with the duty ratio of d can reduce the spin exchange relaxation rate to 2d times of that of a conventional method under the same modulation amplitude and frequency, due to the fact that the spin exchange relaxation rate is effectively restrained, the collected polarizability response signal is obviously improved, and the polarizability response signal can be obtained through the pulse magnetic field with the duty ratio of d and the pulse magnetic field with the duty ratio of d. Low-relaxation-rate sensitivity-enhanced double-axis magnetic field measurement under a pulse modulation scheme is realized, the double-axis measurement sensitivity of a miniaturized SERF atom magnetometer is further improved, and the method has great significance in supporting leap-type development of a future array type extremely-weak magnetic imaging system and medical application thereof.

The invention provides a self-excited cesium optical pump atomic magnetometer and a magnetic field measurement method. The magnetometer comprises a physical probe part and a circuit part. The physical probe part comprises a cesium spectrum lamp, an optical element, a cesium atom absorption gas chamber, a radio frequency coil and a photoelectric detector; the circuit part comprises a photoelectric conversion circuit, a phase-locked amplification circuit and a radio frequency excitation circuit modulated by square waves. A macroscopic magnetic moment is generated by pumping cesium atoms through left-handed circularly polarized light, a radio frequency magnetic field induces Larmor precession, light intensity changes are detected and fed back to a radio frequency coil to form self-oscillation, and the external magnetic field intensity is calculated according to the linear relation between oscillation frequency and the magnetic field. Square wave modulation is adopted to broaden the measurement bandwidth, a magnetic field direction adjusting system is additionally arranged to automatically keep an angle of 45 degrees between an optical axis and a magnetic field so as to eliminate a blind area, the hemisphere automatic switching function is achieved, and the advantages of being high in sensitivity, fast in response, high in adaptability, small in size and low in power consumption are achieved.

The application relates to a light polarization effect detection method of a SERF atomic spin gyroscope. 3 The atomic spin system of He, 2, the pumping light path is turned on, polarization operation is carried out on the two kinds of gases in the atomic gas chamber, the transmission of the electron angular momentum to the nuclear spin angular momentum is realized; 3, the detection light path is turned on, and the light signal is detected; 4, a single pulse disturbance of an alternating magnetic field is applied in the y direction, the K atom is deflected at a small angle, the Larmor precession is generated, the K and 3 The strong coupling effect of He atoms, the precession frequency of the K atoms under different main magnetic fields is linearly fitted, the slope value of the linear fitting is used to calculate the electron spin polarization rate, the intercept value when the applied main magnetic field value is 0 is used to calculate the equivalent magnetic field generated by the nuclear spin, and the direct and indirect polarization effects of the pumping light on the two kinds of atoms are detected by the slope and the intercept value. The effects of the two kinds of atoms polarized directly and indirectly by light are presented in the form of linear numerical fitting.

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 discloses an atomic time grating displacement sensor, and relates to the technical field of quantum precision measurement. The system comprises an atom processing system used for constructing a constant-speed motion reference system, the constant-speed motion reference system is jointly formed by optical pumping atomic nucleus spin polarization, Larmor precession generated by atoms under the action of an external static magnetic field, nuclear magnetic resonance generated by applying a radio frequency magnetic field and the like, and the system further comprises a signal detection system. The signal detection system comprises a detection light generation module, a detection light adjustment module and a detection light acquisition module, detection light is single-light-path detection light, and the signal processing system is used for performing filtering, phase comparison, calculation and other processing on an output detection light signal to obtain an angular displacement value. According to the method, high-uniform-speed motion is constructed by regulating and controlling atomic spinning to serve as a reference datum, lines do not need to be depicted, the problem of precise depicting of an original'spatial grating 'is solved, the reference datum is traced to a quantum state, the method has the advantages of being high in precision, high in sensitivity and the like, and qualitative leap is achieved in technology.

The application provides a magnetic field detection probe, a magnetometer and a gradient magnetometer based on the same. The magnetic field detection probe comprises a pumping light incident light path module, a probe light incident light path module, a beam splitter, an atomic gas chamber and a probe light exit light path module; the atomic gas chamber is filled with gaseous alkali metal atom medium; the beam splitter is used for transmitting incident pumping light output by the pumping light incident light path module and reflecting incident probe light output by the probe light incident light path module, and the two kinds of light are input into the atomic gas chamber along the same incident path, so that the alkali metal atom medium is polarized and the generated macroscopic magnetic moment undergoes Larmor precession under the action of the magnetic field of a magnetic field source to be detected, the incident probe light is affected by the Larmor precession to obtain an exit light signal, the exit light signal is transmitted, polarized, split and double-channel photoelectric detected by the probe light exit light path module, and a first electric signal corresponding to S polarized light and a second electric signal corresponding to P polarized light in the exit light signal are obtained.

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 quantum sensor and device for carrying out dark substance search in a space environment, and relates to the field of quantum sensors. The quantum sensor comprises an integrated laser, an integrated light path, a cubic steam chamber, a driving field coil pair, a magnetic shielding structure, an integrated electronics system, a fiber-optic gyroscope and an anti-radiation shielding box, wherein the integrated electronics system adopts a three-mode circuit redundancy design; the cubic steam chamber comprises double inert gas atoms, alkali metal atoms and a photoelectric detector; the integrated light path obtains pump laser; pumping laser polarizes alkali metal atoms and double inert gas atoms to search for dark substance signals; the photoelectric detector detects a sensing signal, the sensing signal is demodulated by the integrated electronics system, and the Larmor precession frequency of double inert gas atoms is obtained; the optical fiber gyroscope measures the rotation frequency of the quantum sensor, and dark substance signals are continuously obtained in combination with the Larmor precession frequency. According to the invention, space environment interference can be effectively inhibited, and dark substance searching in a space environment is realized.

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.