Researchers led by Patrick Kazansky of the Optoelectronics Research Center at the University of Southampton in the UK have conducted a series of experiments that may further explain light polarization in glass. They used Ge-doped silica glass, which features strong photosensitivity associated with centers deficient in germanium oxygen. They observed strong blue luminescence related to those defects. When the pump beam was focused inside the sample, the spatial isotropy of the blue luminescence was broken. The luminescence scattering increased along the direction of the pump polarization. This led to the conclusion that anisotropic light scattering peaks in the plane of light polarization within isotropic media. Further details of the work appear in the March 8 issue of Physical Review Letters.