In a magnetic field source detecting apparatus, a magnetic sensor unit detects an intensity and a direction of a measurement target magnetic field on or over a surface of a test target object; and a position estimating unit estimates a position in a depth direction of a magnetic field source that exists at an unspecified position inside a test target object on the basis of the intensities and the directions of the measurement target magnetic field detected by the magnetic sensor at at least two 2-dimensional positions of the surface.

A method is provided for sensing a magnetic field in a magnetic gradiometer of the kind in which pump light and light constituting an optical carrier traverse first and second atomic vapor cells that contain host atoms and that are separated from each other by a known distance. According to such method, the host atoms are prepared in a coherent superposition of two quantum states that differ in energy by an amount that is sensitive to an ambient magnetic field. Modulation of the optical carrier in the respective cells gives rise to sidebands that interfere to generate a beat frequency indicative of the magnetic field gradient. The host atoms are prepared at least in a mode that allows measurement of ambient magnetic field components perpendicular to the axis of the pump light. In such mode, the host atoms are spin-polarized by pump light while subjected to a controlled magnetic field directed parallel to the pump beam, and then the controlled magnetic field is adiabatically extinguished.

A sensing probe may be formed of a diamond material comprising one or more spin defects that are configured to emit fluorescent light and are located no more than 50 nm from a sensing surface of the sensing probe. The sensing probe may include an optical outcoupling structure formed by the diamond material and configured to optically guide the fluorescent light toward an output end of the optical outcoupling structure. An optical detector may detect the fluorescent light that is emitted from the spin defects and that exits through the output end of the optical outcoupling structure after being optically guided therethrough. A mounting system may hold the sensing probe and control a distance between the sensing surface of the sensing probe and a surface of a sample while permitting relative motion between the sensing surface and the sample surface.

A sensing probe may be formed of a diamond material comprising one or more spin defects that are configured to emit fluorescent light and are located no more than 50 nm from a sensing surface of the sensing probe. The sensing probe may include an optical outcoupling structure formed by the diamond material and configured to optically guide the fluorescent light toward an output end of the optical outcoupling structure. An optical detector may detect the fluorescent light that is emitted from the spin defects and that exits through the output end of the optical outcoupling structure after being optically guided therethrough. A mounting system may hold the sensing probe and control a distance between the sensing surface of the sensing probe and a surface of a sample while permitting relative motion between the sensing surface and the sample surface.

A sensor system includes a quantum dot including one or more paramagnetic centers. It comprises a control and evaluation device including a pump radiation source, a radiation receiver and which irradiates the quantum dot depending on a transmission signal. The quantum dot emits fluorescence radiation upon irradiation with the pump radiation, which depends on the magnetic flux density and/or on another physical parameter. The control and evaluation device generates an output signal including a measured value as a function of the fluorescence radiation. The control and evaluation device compensatingly readjusts the sensitivity of the quantum dot for the magnetic flux density and/or the other physical parameter by means of one or more compensation coils.

Various embodiments comprise a magnetic field compensation system. In some examples, the system comprises one or more coil drivers, magnetic field coils, and one or more magnetic field sensors. The one or more coil drivers supply a current to the magnetic field coils to generate a magnetic field. The magnetic field coils receive the current and generate the magnetic field. The magnetic field coils may be arranged in an array. The magnetic field coils individually comprise at least one coil trace pattern that encloses an area. The one or more magnetic field sensors measure the magnetic field generated by the magnetic field coils at a location proximate to the magnetic field coils.

An embodiment of the invention relates to a sensor comprising a sensor element (10) for measuring a magnetic field, the sensor element (10) comprising a set of at least two first input ports (I1), a set of at least two exit ports (E) each of which is connected to one of the first input ports (I1) via a corresponding first beam path (B1), a set of at least two second input ports (I2) each of which is connected to a second beam path (B2), wherein the first beam paths (B1) extend through a common plane (CP) located inside the sensor element (10), said plane (CP) comprising a plurality of magneto-optically responsive defect centers, wherein the second beam paths (B2) also extend through said common plane (CP), but are angled with respect to the first beam paths (B1) such that a plurality of intersections between the first and second beam paths (B2) is defined, and wherein each intersection forms a sensor pixel (P) located at at least one of said magneto-optically responsive defect centers.

An embodiment of the invention relates to a sensor comprising a sensor element (10) for measuring a magnetic field, the sensor element (10) comprising a set of at least two first input ports (I1), a set of at least two exit ports (E) each of which is connected to one of the first input ports (I1) via a corresponding first beam path (B1), a set of at least two second input ports (I2) each of which is connected to a second beam path (B2), wherein the first beam paths (B1) extend through a common plane (CP) located inside the sensor element (10), said plane (CP) comprising a plurality of magneto-optically responsive defect centers, wherein the second beam paths (B2) also extend through said common plane (CP), but are angled with respect to the first beam paths (B1) such that a plurality of intersections between the first and second beam paths (B2) is defined, and wherein each intersection forms a sensor pixel (P) located at at least one of said magneto-optically responsive defect centers.

Disclosed are a system and a method for measuring a magnetorefractive effect of an optical fiber. The system comprises a laser, a coupler A, a sensing optical fiber, a reference optical fiber, a carrier generator, a coupler B, a photoelectric detector and a data acquisition and processing module. The coupler A, the sensing optical fiber, the reference optical fiber and the coupler B form a Mach-Zehnder optical fiber interferometer. An external magnetic field influences the refractive index of the sensing optical fiber, so that the optical path difference between two paths of optical signals in the sensing optical fiber and the reference optical fiber is changed, the intensity of an interference optical signal output by the coupler B is changed, and the refractive index change of the sensing optical fiber under the action of the magnetic field is measured by detecting and processing the interference optical intensity.

Disclosed are a system and a method for measuring a magnetorefractive effect of an optical fiber. The system comprises a laser, a coupler A, a sensing optical fiber, a reference optical fiber, a carrier generator, a coupler B, a photoelectric detector and a data acquisition and processing module. The coupler A, the sensing optical fiber, the reference optical fiber and the coupler B form a Mach-Zehnder optical fiber interferometer. An external magnetic field influences the refractive index of the sensing optical fiber, so that the optical path difference between two paths of optical signals in the sensing optical fiber and the reference optical fiber is changed, the intensity of an interference optical signal output by the coupler B is changed, and the refractive index change of the sensing optical fiber under the action of the magnetic field is measured by detecting and processing the interference optical intensity.