If black hole after all the scenario of quantum mechanical process have completed their interactions behave accordingly to Relativity equation to became eventually a tiny speck in space of high intensity mass with very strong gravitation wave could the telescope have picked up such polarization of light from some gravitated wave of dying star or black hole. (religion.blogs.cnn.com)
Structures with this property behave optically as though they are made of two different materials (each with a different refractive index), depending on the orientation of polarization of the light passing through them. (brightfocus.org)
(Note that this type of wave - twisting is fundamentally different from the better - known circular polarization of light.) (discovermagazine.com)