Sensor device comprising a source of fluorescence coupled to a fluorescence collector and magnetometer comprising said device

A sensor device comprising:

• a source of fluorescence comprises a nitrogen-vacancy diamond, wherein said fluorescence is function of a physical phenomenon to be sensed, said physical phenomenon being a magnetic field, and wherein said fluorescence is generated in response to an excitation provided by a source of excitation, said excitation being a light in the green spectrum produced by an excitation light source;
• a collector for collecting said fluorescence;
• a reflector placed around said source of fluorescence to reflect said fluorescence towards said collector,
• wherein said reflector is provided with an opening at its vertex, the source of fluorescence being arranged within said reflector to sense said physical phenomenon through said opening.