Patent ID: 7576905

Claim:
An apparatus for controllably modulating light diffracted therefrom, the apparatus comprising: an electrophoretic medium comprising index-modifying ions, the index-modifying ions having characteristics whereby a presence of a sufficient concentration of index-modifying ions in a particular region modifies a local refractive index in the particular region; a controllable voltage source connected to create a first electric field pattern in the electrophoretic medium, the first electric field pattern causing electrophoretic movement of the index-modifying ions into a first spatial distribution resulting in a first diffraction pattern of light diffracted from the apparatus, and to create a second electric field pattern in the electrophoretic medium, the second electric field pattern causing electrophoretic movement of the index-modifying ions into a second spatial distribution resulting in a second diffraction pattern of light diffracted from the apparatus; wherein the first and second diffraction patterns differ from one another by at least one of: an optical power distribution within their respective diffraction orders; and an angular orientation of their respective diffraction orders with respect to a common normal; wherein the voltage source is connected between at least one first electrode contiguous with an interface of the electrophoretic medium and at least one second electrode spaced apart from the at least one first electrode; and wherein at least one of the at least one first electrode and the at least one second electrode is coated with a nano-structured layer or a nano-porous layer.