A measuring device for determining magnetic properties of a magnetizable test specimen comprises a measuring coil winding which passes around a magnetizable measuring coil core. The measuring coil core comprises magnetic flux passage faces arranged at a distance from one another. The test specimen is arranged adjacently to the magnetic flux passage faces. A high-current pulse through the measuring coil winding causes a magnetic flux through the measuring coil core and the test specimen. A temporal profile of electrical characteristic variables of the measuring coil winding is detected using a sensor device. The electrical characteristic variables of the measuring coil winding detected by the sensor device are set in a ratio to additionally ascertained electrical characteristic variables of the measuring coil winding without the test specimen. A magnetic property of the test specimen is determined from the ratio of the electrical characteristic variables to one another.

A chip-type three-dimensional magnetic field sensor includes a light source (1), an input straight waveguide (2), a polarization beam splitting waveguide (3), a 1:1 power beam splitter (4), three 1:2 type Y waveguides, three 2:1 type Y waveguides, three output straight waveguides, three magneto-optical waveguides and three photodetectors. The light source (1) outputs broad-spectrum depolarized light into the input straight waveguide (2), and then the light is divided into TE (transverse electric) polarized light and TM (transverse magnetic) polarized light. The TE polarized light is divided into two beams of TE polarized branch light. The TM polarized light is divided into two beams of TM polarized branch light. One of the two beams of TM polarized branch light is divided into two beams of first TM polarized sub-branch light. Another of the two beams of TM polarized branch light is divided into two beams of second TM polarized sub-branch light.

A magnetic field measurement system includes at least one magnetometer having a vapor cell, a light source to direct light through the vapor cell, and a detector to receive light directed through the vapor cell; at least one magnetic field generator disposed adjacent the vapor cell; and a feedback circuit coupled to the at least one magnetic field generator and the detector of the at least one magnetometer. The feedback circuit includes a first feedback loop that includes a first low pass filter with a first cutoff frequency and a second feedback loop that includes a second low pass filter with a second cutoff frequency. The first and second feedback loops are configured to compensate for magnetic field variations having a frequency lower than the first or second cutoff frequency, respectively.

A magnetic field measurement system includes at least one magnetometer having a vapor cell, a light source to direct light through the vapor cell, and a detector to receive light directed through the vapor cell; at least one magnetic field generator disposed adjacent the vapor cell; and a feedback circuit coupled to the at least one magnetic field generator and the detector of the at least one magnetometer. The feedback circuit includes a first feedback loop that includes a first low pass filter with a first cutoff frequency and a second feedback loop that includes a second low pass filter with a second cutoff frequency. The first and second feedback loops are configured to compensate for magnetic field variations having a frequency lower than the first or second cutoff frequency, respectively.

Systems and methods of quantum sensing include obtaining information regarding a target signal in electronic spin states of quantum defects in an ensemble of quantum defects, mapping the information regarding the target signal from the electronic spin states of the quantum defects to corresponding nuclear spin states associated with the quantum defects, applying a light pulse to the ensemble of quantum defects to reset the electronic spin states of the quantum defects, and repeating a readout stage a plurality of times within a readout duration. The readout stage includes mapping the information regarding the target signal back from the nuclear spin states to the corresponding electronic spin states and applying a data acquisition readout pulse to optically measure the electronic spin states of the quantum defects.

Various embodiments disclosed herein comprise systems and methods to locate magnetic field sensors. In some examples, a system comprises a controller, a sensor mount, a coil set comprising one or more coils, and a magnetic field sensor. The sensor mount mounts the magnetic field sensor and constrains at least one degree of freedom of the magnetic field sensor in position or orientation. The controller supplies electric current to the coil set. The coil set generates magnetic waves that form at least one coil magnetic field in response to receiving the current. The magnetic field sensor measures the strength of the coil magnetic field. The controller locates the magnetic field sensor based on the constraint and the measured strength of the coil magnetic field.

Various embodiments disclosed herein comprise systems and methods to locate magnetic field sensors. In some examples, a system comprises a controller, a sensor mount, a coil set comprising one or more coils, and a magnetic field sensor. The sensor mount mounts the magnetic field sensor and constrains at least one degree of freedom of the magnetic field sensor in position or orientation. The controller supplies electric current to the coil set. The coil set generates magnetic waves that form at least one coil magnetic field in response to receiving the current. The magnetic field sensor measures the strength of the coil magnetic field. The controller locates the magnetic field sensor based on the constraint and the measured strength of the coil magnetic field.

Disclosed is a measurement system for analysing RF signals. The measurement system includes an optically transparent enclosure including an optically pumpable gas, and a printed circuit board, PCB including an electrical transmission line for guiding the RF signal to be analyzed through the enclosure and a reflective planar face. The measurement system includes an optical pump for emitting preferably coherent light onto the reflective planar face, and a detector for detecting an optical property of the emitted light being reflected by the reflective planar face. This provides a better laser/microwave overlap in atomic vapor quantum sensing setups, where it is crucial to overlap the regions with highest laser intensity and microwave field strength.

A spin-orbit torque (SOT) measuring apparatus includes a photoelastic modulator (PEM) configured to periodically modulate a polarization direction of linearly polarized incident light and emit a periodically modulated light, a first polarization rotator configured to rotate a polarization direction of the periodically modulated light, a voltage generator configured to generate an AC current to a sample to which light with the rotated polarization direction is to be emitted, a prism configured to split light reflected into first light and second light having different polarization directions, a balanced detector configured to output a signal corresponding to an intensity difference between the first light and the second light, a changing circuit configured to change a frequency component to the intensity difference, and an amplitude measurer configured to measure an amplitude of a frequency component corresponding to a modulation frequency of the PEM with the changed frequency component.

A magnetic material observation method in accordance with the present invention includes: an irradiating step including irradiating a region of a sample with an excitation beam and thereby allowing a magnetic element contained in the sample to radiate a characteristic X-ray; a detecting step including detecting intensities of a right-handed circularly polarized component and a left-handed circularly polarized component contained in the characteristic X-ray; and a calculating step including calculating the difference between the intensity of the right-handed circularly polarized component and the intensity of the left-handed circularly polarized component. Reference to such a difference enables precise measurement of the direction or magnitude of magnetization without strict limitations as to the sample.