AN ALL-OPTICAL QUANTUM SENSOR FOR MAGNETIC FIELDS

The invention relates to a quantum spin-based optical sensor system (1) for measuring a characteristic quantity in magnetometry or gyroscopy, the system (1) comprising the following components:- a crystal (2) comprising a photoluminescent color-center (20) having a defect-axis (200) along an axis of symmetry of the color-center (20), wherein the color-center (20) comprises a defect-atom (21) arranged on the defect-axis (200), wherein the defect-atom (21) exhibits a nuclear spin that is polarizable with light (100), and wherein the color-center (20) exhibits a nuclear spin-dependent photoluminescence characteristic,- a light source (3) configured and arranged to excite the color-center (20) with light (100),- a detector (4) configured and arranged to record a photoluminescence signal (101) emitted from the color-center (20),a field-generating device (5) configured and adapted to generate a static magnetic field, wherein a magnetic field vector (500) of the generated magnetic field at the crystal (2) encloses an angle (θ) with the defect-axis (200) with a magnitude in the range of 0.1° or greater.