An interference type optical magnetic field sensor device 1 has a light emitter 10 emitting first linearly polarized light, a first optical element 30 emitting a first linearly polarized wave and a second linearly polarized wave orthogonal to the first linearly polarized wave with respect to incident the first linearly polarized light, and emitting a second linearly polarized light with respect to incident third linearly polarized wave and a forth linearly polarized wave orthogonal to the third linearly polarized wave, a magnetic field sensor element 50 disposed at least a portion thereof within a predetermined magnetic field an optical path unit 40 connected to the first optical element and the magnetic field sensor element, and having a first optical path propagating the first linearly polarized wave and the forth linearly polarized wave, and a second optical path propagating the second linearly polarized wave and the third linearly polarized wave, a detection signal generator 60 outputting a detection signal by separating the second linearly polarized light into an S polarization component and a P polarization component, converting the S polarization component and the P polarization component into an electric signal, and an optical branching element 20 transmitting the first linearly polarized light to the first optical element, and branching the second linearly polarized light to the detection signal generator, wherein the magnetic field sensor element emits the first linearly polarized wave and the second linearly polarized wave as incident light, and emits the third linearly polarized wave with respect to the first linearly polarized wave and the forth linearly polarized wave with respect to the second linearly polarized wave as return light.

A magnetic field measurement cable (10) of the present disclosure includes an electric cable (1) provided at an axial part, and an outer circumferential cable (2) provided on the outer side of the electric cable (1) and helically formed by a plurality of steel wires helically wound and a magnetic field measurement optical cable (3) having an optical fiber cable (3a).

A measurement device for measuring MR signals in a MR device may include first and second magnetometers and a controller. The first magnetometer may be a quantum spin magnetometer that includes a sensor material having a spin defect center including Zeeman splitting states dependent on an external magnetic field of the MR device, an optical excitation source and a microwave excitation source for electromagnetically exciting the sensor material, and a measurement sensor for measuring optical signals emitted by the excited sensor material element and depending on the Zeeman splitting states. The controller may be configured to determine a working frequency of the microwave excitation source of the first magnetometer from the total magnetic field strength measured by the second magnetometer, and control the microwave excitation source to use the determined working frequency as microwave frequency, such that the first magnetometer measures the MR signals as the optical signal.

In order to carry out the polarimetric detection of a measurand, light of two polarization states is passed through a sensing element, where the two states suffer a differential phase shift depending on the value of the measurand. In order to compensate for only imperfections of the device, a method is proposed that is based on calibration values obtained in a low-value regime of the measurand only. Yet the method can still be used for accurately determining higher values of the measurand.

A full-polarization Faraday magnetic field sensor based on a Sagnac interference system and a modulation method are provided. The full-polarization Faraday magnetic field sensor includes a light source, an optical fiber coupler, a polarizer, a polarization beam splitter, a polarization controller, a magnetic field sensing unit, a detector and a polarization maintaining optical fiber. An optical signal is emitted by the light source, passes through the optical fiber coupler and the polarizer in sequence, and is divided into a clockwise path and an anticlockwise path by the polarization beam splitter. Angles between fast axis directions of the two polarization maintaining optical fiber loops and a polarization direction of the polarizer are respectively clockwise 45° and anticlockwise 45°. The two polarization maintaining optical fiber loops has opposite winding directions, a same diameter, and a same number of winding turns.

The processing of information is performed using a magneto-optic circuit that modifies the polarization of light using the Kerr effect. Magneto-optic circuits perform digital-to-analog conversion, comparison of values, and mathematical operations. Current carrying wires pass near a fiber-optic that carries polarized light. Each individual wire contributes a modification to the polarization of the light based on the current carried in each wire. The modified light is passed through a polarizer, and the intensity of the light may be measured with a photodiode to produce an electrical signal representing a result.

A cell for a optically pumped magnetic sensor measures magnetic field by setting alkali metal atoms to a predetermined excitation state by a pump beam and detecting the excitation state by a probe beam. The cell is provided with a glass substrate which seals the alkali metal atoms and an enclosing gas and transmits the pump beam and the probe beam and a coating layer provided on an inner surface of the glass substrate. The coating layer is made of an inorganic material.

An atomic magnetometer, and a method for using same is disclosed. The method for measuring an ambient magnetic field uses an atomic magnetometer that has a probe light beam with a probe axis that probes a polarization vector of an atomic population confined within a vapor cell. The method employs one or more measurement cycles. In each measurement cycle, the polarization vector is prepared in an initial state via an optical pumping pulse. The vapor cell is then subjected to the ambient magnetic field, which results in rotation of the polarization vector by Larmor precession. Within the measurement cycle, at a point in time after the polarization vector has been prepared in the initial state, the ambient magnetic field rotates the direction of the polarization vector, and at least one measurement is made of a projection of the Larmor-rotated polarization vector onto the probe axis during or after application of a magnetic waveform.

High-sensitivity multi-channel atomic magnetometers are described. Methods for operating multi-channel atomic magnetometers are also described. Moreover, devices incorporating a plurality of multi-channel atomic magnetometers are described. A multi-channel atomic magnetometer may use the spin-exchange relaxation-free (SERF) technique. A multi-channel atomic magnetometer may achieve multi-channel operation in a single module, reducing the cost of sensors. A multi-channel atomic magnetometer may be a 16-channel atomic magnetometer. A multi-channel atomic magnetometer may include a single large vapor cell including alkali-metal atoms and at least one buffer gas that restricts motion of atomic spins of the alkali-metal atoms, thereby making relatively small internal cell volumes act as a multiple independent local sensing channels. A multi-channel atomic magnetometer may include a broad pump beam that simultaneously polarizes all (or substantially all) of the alkali-metal atoms in each internal sensing volume of the vapor cell, and a broad probe beam that simultaneously measures magnetic fields at multiple sensing volumes with a photodiode array.

An inspection apparatus comprises a light output unit configured to output first light having a first wavelength and second light having a second wavelength, a magneto-optical crystal arranged so that a reflection film faces a measurement target, a light detection unit configured to detect the first light and the second light, and a light guide optical system configured to guide the first light and the second light toward the magneto-optical crystal and the measurement target, and guide the first light reflected by the magneto-optical crystal and the second light reflected by the measurement target toward the light detection unit. The light guide optical system comprises an optical path switching element configured to perform switching between optical paths of a plurality of optical elements so that the first light and the second light are selectively incident on the light detection unit.