Weak value amplification of an optical Faraday differential refraction effect.
In the presence of a longitudinal magnetic field B, a beam of linearly polarized light incident from a Faraday medium of Verdet constant V refracts at its interface with a medium of negligible Verdet constant and emerges as two opposite circularly polarized beams that are separated by a small divergence angle δ that is proportional to the product BV. Judicious postselection of the polarization state of the emergent light can be used to amplify the measured value of δ by several orders of magnitude. This technique makes it possible to optically measure either very small V values when B is known or small magnetic fields when V is known.
Electromagnetic and Sensor Systems Department Naval Surface Warfare Center Dahlgren Division, Dahlgren, Virginia 22448, USA. allen.parks@navy.mil
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