Progress on the Development of a Magnetic Field Sensor

This project aims to develop a magnetic field sensor by using the special properties of quantum entangled photons to intensify the sensitivity of a Faraday effect based sensor. The Faraday effect occurs when the polarization of light rotates as it passes through select materials in the presence of a magnetic field. For our set up, we chose crystals with high Verdet constants: Cd0.57Mn0.43Te andCd0.86Mn0.14Te. The introduction of a super magnet creates a measurable polarization rotation in light passing through the selected crystals. Using a magnet in the shape of an annulus, we experimented with a variety of geometrical configurations in an attempt to maximize the rotation produced by the magnet and crystal. In the first set up, we mounted the magnet in close proximity to the crystal. In later designs, we placed the crystal inside of the super magnet by 3-D printing a structure to hold the crystal. Generating position-momentum entangled photons through parametric down-conversion, our goal is to use the quantum nature of the photons to create a highly sensitive magnetic field sensor.