A useful generalization of the Martinelli effect

Abstract

It was shown recently that the final polarization state of a light beam that retraces its path through a medium after reflecting off a mirrored 45° Faraday rotator is orthogonal to an arbitrary initial state and is independent of all details of the birefringence of the medium. Using a recent method for analyzing such propagation it is shown that this result is true in the presence of an arbitrary reciprocal dichroism in addition to birefringence in the medium. It can therefore be useful in experiments to look for polarization changes arising from broken T-symmetry states in a medium.