42 results about "Larmor precession" patented technology

The invention discloses a rubidium atomic magnetometer and a magnetic field measuring method. Based on the principle of nonlinear magneto-optic rotation, and through combination of timing control and tracking type frequency locking control, the atomic magnetometer achieves a large dynamic measurement range, high magnetic field sampling rate and high sensitivity. A DSP timing control module controls on-off of an acousto-optic modulator and a radio-frequency signal source in the physical part of the rubidium atomic magnetometer according to timing combination to adjust the magnetic field sampling rate N. The DSP timing control module further controls acquisition triggering of a data acquisition card. A calculation unit gets the Larmor precession frequency (f) through fast Fourier transform with use of a received rubidium atom Larmor precession free relaxation signal, and further calculates the value of an external magnetic field. The calculation unit selects a high magnetic field sampling rate module or a low magnetic field sampling rate module before measurement according to the pre-judged dynamic range of a to-be-measured magnetic field, and sets whether a tracking type frequency locking work mode is used when the low magnetic field sampling rate module is selected. In the working process, data is acquired and processed, and the value of the magnetic field is output.

A method for determining a pulse duration T90 of a 90° pulse in a nuclear magnetic measuring method. A signal generator has a known generator resistance RS, wherein a coil has a coil impedance ZL with a coil resistance RL and a coil reactance XL, wherein a coupling circuit has an adjustable matching capacitance CM and an adjustable tuning capacitance CT, and wherein the medium has a Larmor precession having an angular Larmor frequency ωP. The time needed for determining the pulse duration T90 of the 90° pulse is reduced by the matching capacitance CM and the tuning capacitance CT being set so that the angular resonance frequency ω0 corresponds to the angular Larmor frequency ωP and by power matching being present between the signal generator and the coil. The coil resistance RL is determined and the pulse duration T90 is determined as a function of the coil resistance RL.

The invention relates to the technical field of microwave electronic equipment, and provides a microwave power detector based on the spin pumping effect and a preparation method thereof. The microwave power detector based on the spin pumping effect includes a micro-nano scale device, and the micro-nano scale The device includes a heterogeneous structure composed of a magnetic thin film layer and a nonmagnetic heavy metal thin film layer. The nonmagnetic heavy metal thin film layer is grown on the magnetic thin film layer; the magnetic moment of the magnetic thin film layer of the micro-nano scale device undergoes ferromagnetic resonance under microwave excitation. Larmor precession, the spin pump generates spin current and injects it into the non-magnetic heavy metal thin film layer. During the test of the inverse spin Hall voltage, the magnetic field integral value of the inverse spin Hall voltage and the value of the microwave power Satisfying a certain linear relationship, the detector has a simple structure, reduces the manufacturing cost of the detector, has a wide range of testing frequencies, high linearity of testing microwave power, and a wide range of applications.

The invention relates to an atomic spin procession detecting method and an atomic spin precession detecting device based on electro-optic modulation. Alkali metal atoms in a spin-exchange relaxation free state are used for sensing an external magnetic field or angular rate, thereby generating atomic spin Larmor precession. An electro-optic modulator is used for performing electro-optic modulation on detected laser. Through output light strength detection by the electro-optic modulator and demodulation of a phase-locked amplifier, output light strength and frequency doubling signal strength are obtained. Finally a signal acquisition and processing circuit measures an atomic spin precession signal, and furthermore measurement to the external magnetic field or inertia can be realized. According to the atomic spin procession detecting method and the atomic spin procession detecting device, advantages such as simple modulation, small size, high sensitivity, low temperature effect and simple operation condition in the electro-optic modulator are exerted. The atomic spin procession detecting method and the atomic spin procession detecting device have relatively high sensitivity and relatively high stability. The novel atomic spin procession detecting method is based on an atomic spin effect and can be used for industrial integration and practical application of atomic spin sensing devices in future.