The present disclosure discloses an optical measurement device and method for a plasma magnetic field with adjustable sensitivity. The method comprises the following steps: constructing an optical rotation measurement system based on a pulsed laser beam for measuring an optical rotation image and a shadow image; processing the optical rotation image and the shadow image, and obtaining a distribution of proportional coefficients based on alight intensity distribution; obtaining a distribution of rotation angles based on a mapping relationship between the proportional coefficients and the rotation angles; constructing an interference measurement system based on the pulsed laser beam, and measuring a phase shift of an interference image; calculating a distribution of electron areal densities based on the phase shift in the interference image; obtaining a two-dimensional distribution of an average magnetic field based on the rotation angles and the electron areal densities.

An object of the present invention is to provide a magneto-optical material capable of exhibiting the Faraday effect even though no magnetic field is applied. The magneto-optical material of the present invention has a nanogranular structure in which magnetic nanoparticles are dispersed in a fluoride matrix, and can exhibit Faraday properties without requiring the application of a magnetic field because the magnetic nanoparticles are configured by a magnetic material that has residual magnetization and consists of any of a FePt alloy, a CoPt alloy, a FeCoNiAl alloy, a Co ferrite, or a Ba ferrite.

The invention provides a method for measuring the magnetic field of an electromagnetic component having the steps of: instrumenting one or more portions of an electromagnetic component by placing an optical fiber in electromagnetic communication with the one or more portions of said electromagnetic component; energizing the electromagnetic component; interrogating the optical fiber using light and an optical detector; and determining changes in the magnetic field incident on the optical fiber based on the detected changes in the light received by the optical detector.

A magnetic field sensor element 1 includes a light emitter 10 emitting a first linearly polarized light, a first optical element 20 emitting a first linearly polarized wave and the second linearly polarized wave in response to a first linearly polarized light incident, and emitting a second linearly polarized light in response to a third linearly polarized wave and the a linearly polarized wave incident, at least one pair of magnetic field sensor elements 50 capable of disposing in a predetermined magnetic field across the measured conductor, having a light transmissive, changing the phase of transmitted light in accordance with the magnetic field, and fixing a relative position therebetween, an optical path 30 including a first optical path propagating the first linearly polarized wave and the fourth linearly polarized wave, and a second optical path propagating the second linearly polarized wave and the third linearly polarized wave, and connected to the first optical element and the magnetic field sensor element, a detected signal generator 60 outputting a detected signal corresponding to the magnetic field, by receiving two components of the second linearly polarized light, and converting to the electrical signal, and an optical branching element transmitting the first linearly polarized light to the first optical element and branching the second linearly polarized light to the detected signal generator.

A fiber-optic current sensor uses a highly-birefringent spun fiber as sensing fiber. The light is fed through a retarder, which is a detuned quarter-wave or half-wave retarder. It is shown that such detuning can be used to compensate for temperature dependencies of the sensing head.

In a magnetic field measurement apparatus, a light source irradiates a gas cell with linearly polarized light serving as pump light and probe light in a Z axis direction, and a magnetic field generator applies, to the gas cell, a magnetic field A.sub.x which is a time function f(t) having the amplitude A.sub.0 taking n fixed values f.sub.i (where i=1, . . . , and n), and a magnetic field A.sub.y which is a time function g(t) having the amplitude A.sub.0 taking m fixed values g.sub.j (where j=1, . . . , and m) in each of X axis and Y axis directions. A calculation controller calculates a magnetic field C (C.sub.x, C.sub.y, C.sub.z) of a measurement region using the X axis and Y axis components A.sub.x and A.sub.y of an artificial magnetic field A, and a spin polarization degree M.sub.x corresponding to a measurement value W.sub.? from a magnetic sensor.

In a magnetic field measurement apparatus, a light source irradiates a gas cell with linearly polarized light serving as pump light and probe light in a Z axis direction, and a magnetic field generator applies, to the gas cell, a magnetic field A.sub.x which is a time function f(t) having the amplitude A.sub.0 taking n fixed values f.sub.i (where i=1, . . . , and n), and a magnetic field A.sub.y which is a time function g(t) having the amplitude A.sub.0 taking m fixed values g.sub.j (where j=1, . . . , and m) in each of X axis and Y axis directions. A calculation controller calculates a magnetic field C (C.sub.x, C.sub.y, C.sub.z) of a measurement region using the X axis and Y axis components A.sub.x and A.sub.y of an artificial magnetic field A, and a spin polarization degree M.sub.x corresponding to a measurement value W.sub.? from a magnetic sensor.

One embodiment of the invention includes a magnetometer system. The system includes a sensor cell comprising alkali metal particles and at least one nuclear spin isotope. The system also includes a probe laser to provide a probe beam through the sensor cell to generate a detection beam, and a magnetic field system to generate magnetic fields through the sensor cell. The system also includes a detection system to implement detection of an external magnetic field based on characteristics of the detection beam in response to precession of the at least one nuclear spin isotope based on the magnetic fields. The system further includes a calibration controller configured to calibrate the magnetometer system based on implementing predetermined changes to the magnetic fields and monitoring the detection beam in a feedback manner.

Optical fiber based current measuring equipment for measuring the current circulating through a conductor. The equipment includes an interrogator having a light emitter and a light receiver, and a sensing portion close to the conductor, the interrogator and the sensing portion being connected through at least one standard single-mode intermediate fiber. The light emitter of the interrogator is configured to emit sets of at least two polarized light pulses to the sensing portion, the pulses being polarized with a specific degree difference, and the light receiver (4) is configured to determine the current circulating through the conductor depending on the pulses it receives in return from the sensing portion. A method for measuring the current circulating through a conductor with the use of an optical fiber based current measuring equipment is also provided.

A magnetic field sensor head detects a magnetic field occurring when a current flows through a conductor, and has an optical fiber having a magnetic film arranged on the end surface and a reflective film arranged on the magnetic film; and a magnetic material arranged in the form of a ring around a conductor and containing the magnetic film, wherein the magnetic material has a first taper portion formed so that a cross-sectional area perpendicular to the orientation of the magnetic flux becomes smaller as approaching the magnetic film in order to concentrate a magnetic flux occurring when a current flows through a conductor on an area in which the magnetic film is arranged.