Abstract: A defect centre-based sensor is disclosed. The sensor comprises instrumentation which includes a generator for causing excitation in an active element, for example a diamond, and a detector for measuring a transition in the active element. The generator is an optical source and/or the detector is an optical detector. The sensor further comprises an optical waveguide and a sensor head in communication with the source and/or the detector via the optical waveguide. The sensor head houses the active element having at least one defect centre, for example, a nitrogen vacancy, responsive to an applied magnetic field, electric field or temperature and a signal delivery arrangement, for example at least one lens, arranged to optically couple the optical waveguide to the active element.

Abstract: Sensor A device is disclosed. The device comprises a magnet (15) arranged to apply an inhomogeneous magnetic field (B) to a given volume (16) and a magnetometer having an active element (8) for sensing magnetic field in a volume which includes the given volume (16).

Abstract: A defect centre-based sensor is disclosed. The sensor comprises instrumentation which includes a generator for causing excitation in an active element, for example a diamond, and a detector for measuring a transition in the active element. The generator is an optical source and/or the detector is an optical detector. The sensor further comprises an optical waveguide and a sensor head in communication with the source and/or the detector via the optical waveguide. The sensor head houses the active element having at least one defect centre, for example, a nitrogen vacancy, responsive to an applied magnetic field, electric field or temperature and a signal delivery arrangement, for example at least one lens, arranged to optically couple the optical waveguide to the active element.

Abstract: Multiple SQUID magnetometers that include at least two SQUID loops, each of which is composed of at least two Josephson Junctions connected in parallel with superconducting wires, are provided. The SQUID loops are fabricated such that they share a common Josephson Junction. Devices and application that employ the multiple SQUID magnetometers are also provided.