Ultrasensitive magnetic sensor with magneto-optically active material with high verdet constant

A sensor of magnetic fields for use with a light source, comprising:

• a beam splitter for splitting a light beam into a first and second direction,
• a magnetic sensor probe in a magnetic field for receiving light in the first direction and for returning light with a rotated polarization in accordance with the magnetic field, and
• a detector for detecting the returning light to thereby provide a value relating to the magnitude of the magnetic field, whereby the magnetic sensor probe comprises an inorganic magneto-optically active film, or an organic magneto-optically active film, or both;
• wherein the magnetic sensor probe comprises two optical fibers, and the inorganic magneto-optically active film, or the organic magneto-optically active film, or both are integrated into a reflective termination of the two optical fibers.

A method of sensing a magnetic field, the method comprising:

• directing a light beam through a magnetic sensor probe in a magnetic field and receiving returning light with a rotated polarization in accordance with the magnetic field from the magnetic sensor probe;
• and
• detecting received light to thereby provide a value relating to the magnitude of the magnetic field
• wherein the directing a light beam through the magnetic sensor probe includes:
• directing the light through an inorganic magneto-optically active film, or an organic magneto-optically active film, or both;
• wherein the film comprises a polymer that further includes superparamagnetic particles;
• wherein a Verdet constant of the film is increased by one or a combination of the following:
• poling, aligning and doping the superparamagnetic particles;
• and
• arranging the film to transmit the light received by the magnetic sensor probe.