Polarization light modulators are based on an interferometric design in which a polarizing beam splitter serves as a polarizer and analyzer. A polarization displacement device shifts orthogonally polarized light beams parallel to the long axis of their elongated cross sections. Phase shifts are imparted...http://www.google.co.uk/patents/US7286277?utm_source=gb-gplus-sharePatent US7286277 - Polarization light modulator
