System of quantum sensors for magnetoencephalography

A method of building a magnetic field map of an object in a measurement system, the system comprising:

• a light source arrangement for generating a plurality of light beams, a respective light beam being configured to travel in the measurement system along a respective optical path;
• a plurality of measurement sensors, a respective measurement sensor being configured to receive the respective light beam along the respective optical path, the plurality of measurement sensors sharing a first magneto-optical layer comprising at least a first Faraday material layer and a first light reflector for reflecting the plurality of lights beams travelled through the first Faraday material layer in a first direction back to the first Faraday material layer in a second, opposite direction, the first magneto-optical layer being configured to rotate polarization of the plurality of light beams in the presence of a magnetic field such that the amount of rotation depends on the strength of the magnetic field;
• one or more reference sensors arranged at a given distance from the plurality of measurement sensors, a respective reference sensor being configured to receive the respective light beam along the respective optical path, the one or more reference sensors comprising a second magneto-optical layer comprising at least a second Faraday material layer and a second light reflector for reflecting the respective light beams travelled through the second Faraday material layer in a first direction back to the second Faraday material layer in a second, opposite direction, the second magneto-optical layer being configured to rotate polarization of the respective light beam in the presence of a magnetic field such that the amount of rotation depends on the strength of the magnetic field;
• and
• one or more light detectors for receiving the light beams travelled in the second direction from the plurality of measurement sensors and the one or more reference sensors to determine light intensity values of the received light beams to thereby determine polarization rotation values of the received light beams for building the magnetic field map,
• the method comprising the steps of:
• the light source arrangement emitting the plurality of light beams;
• and
• the one or more light detectors determining the light intensity values of the received light beams to thereby determine polarization rotation values of the received light beams with respect to the emitted plurality of light beams for building the magnetic field map.