Considering that birefringence results from a difference in effective propagation velocity of the electromagnetic field through an anisotropic refractive media, would it be practical to design a polarization diversity interferometer?
In astronomical observations radiation from distant objects frequently passes through clouds of charged particles that are immersed in a magnetic field. It would seem that a device that could measure the correlation function of the e and o waves as a function of time delay of the earlier wave could reveal much information about the media through which the radiation has passed. This in conjunction with time dispersion measurements could provide a powerful measurement tool. In particular, I am interested to know if any such measurements could be made of regions thought to be rich in dark matter.