Differentiating spatial light modulator
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorDavid Armitage
Life of this patent
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Abstract
A differentiating spatial light modulator device in which a photoreceptor and an electro-optic crystal are isolated by a dielectric mirror. The electro-optic crystal is configured to have low or zero longitudinal response, yet is sensitive to transverse electric fields. The fringe field generated by the photoreceptor (photodiode) modultes the crystal birefringence. Readout via a polarizing beamsplitter gives an output light related to the spatial gradient of the input light. In a liquid crystal embodiment of the invention, reversal of the applied voltage gives a driven off state which speeds the erasure. Storage is possible in the smectic liquid crystal phase.
Claims7
A spatial light modulator which comprises:
- a silicon substrate having a first surface and an opposed second surface, said substrate having p-type silicon material diffused in said first surface thereof to form a photodiode and a charge confinement grid formed in said second surface thereof to prevent lateral charge transfer;
- a dielectric mirror having a first surface and an opposed second surface, the first surface of said mirror being adjacent said second surface of said silicon substrate;
- a transverse electro-optic crystal having a first surface and an opposed second surface, the first surface thereof being adjacent the second surface of said dielectric mirror, said transverse electro-optic crystal having substantially no response to longitudinally applied electric fields and having a substantial response to transversely applied electric fields;
- a transparent electrode having a first surface and an opposed second surface, the first surface thereof being adjacent the second surface of said electro-optic crystal;
- a transparent supporting substrate having a first surface and an opposed second surface, the first surface thereof being adjacent the second surface of said transparent electrode;
- and,
- means for applying a voltage between said p-type material and said transparent electrode.
Dependencies are inferred from the claim text.