A spatial light modulator (SLM) having a phase mask that is provided as an internal component thereof. The phase mask can be provided as a multilevel surface of relatively higher index of refraction material on an inner surface of a transmissive cover window or as a separate transmissive window between...http://www.google.com.au/patents/US8107344?utm_source=gb-gplus-sharePatent US8107344 - Phase masks for use in holographic data storage
