 Liquid crystal display |
| Accordingly, it is a first object of the present invention to provide a liquid crystal display ... |
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| Reflective image-providing display viewed with holographically diffused ambient light |
| OF THE INVENTIVE SUBJECT MATTER The present invention encompasses a display viewable by reflection,... |
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| Self calibrating scanner with single or multiple detector arrays and single or multiple optical systems |
| Accordingly, it is a general object of the present invention to provide a system for image scanning ... |
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| Holographic verification system with indexed memory |
| The present invention provides a holographic data verification system which is capable of ... |
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| Manufacture of security tapes and security threads |
| What is claimed is: 1. A method of manufacturing a laminate structure for use in a security thread ... |
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| Hydraulic transfer method and device and hydraulic-transfer article |
| What is claimed is: 1. A liquid pressure transfer method for transferring a print pattern on a ... |
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| Use of fresnel zone plates for material processing |
| It is an advantage of the present invention to provide a system which uses diffractive optics ... |
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| Ambient turn-on suppression hologram |
| These and other objects of the invention are provided by a hologram which includes a light source, ... |
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| Method of producing switchable holograms |
| A method of producing a switchable hologram generally comprises providing a substrate composed of a ... |
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LTG AlGaAs non-linear optical material and devices fabricated therefrom
| Details |
Inventors: Freeouf, John L.; Hodgson, Rodney T.; Kirchner, Peter D.; Melloch, Michael R.; Woodall, Jerry M.; Nolte, David D.;
Assignee: International Business Machines Corporation (Armonk, NY)
Primary Examiner: Lerner; Martin
Assistant Examiner:
Attorney, Agent or Firm: Perman & Green
A light responsive device (10) has a body (12) that includes a matrix comprised of Group III-V material, the matrix having inclusions (14) comprised of a Group V material contained therein. The body is responsive to a presence of a light beam that has a spatially varying intensity for modifying in a corresponding spatially varying manner a distribution of trapped photoexcited charge carriers within the body. The distribution of trapped charge carriers induces a corresponding spatial variation in at least one optical property of the Group III-V material, such as the index of refraction of the Group III-V material and/or an absorption coefficient of the Group III-V material. The Group III-V material is comprised of LTG GaAs:As or LTG AlGaAs:As. In an optical storage medium embodiment of the invention the spatial variation in the intensity of the light beam results from a simultaneous application of a first light beam (LB1) and a second light beam (LB2) to the body, and from interference fringes resulting from an intersection of said first and second light beams. |
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DETAILED DESCRIPTION The foregoing problems are overcome and the objects of the invention are realized by a light responsive device having a body that includes a semiconductor material that exhibits an excitonic transition, the semiconductor material containing metallic inclusions.
In an exemplary embodiment of the invention, the light responsive device includes a matrix comprised of a Group III-V material, the matrix having inclusions comprised of a Group V material contained therein.
The body is responsive to a presence of a light beam that has a spatially varying intensity for modifying in a corresponding spatially varying manner a distribution of photoexcited charge carriers within the body.
The photoexcited charge carriers are trapped locally by the Group V inclusions, thereby inducing a corresponding spatial variation in at least one optical property of the Group III-V material.
The at least one optical property is an index of refraction of the Group III-V material and/or an absorption coefficient of the Group III-V material.
In an optical storage medium embodiment of the invention, and also in an information storage and retrieval system embodiment of the invention, the spatial variation in the intensity of the light beam results from a simultaneous application of a first light beam and a second light beam to the body, and from interference fringes resulting from an intersection of said first and second light beams.
An embodiment of the invention that is shown to provide photorefractive gain, wherein there is a non-reciprocal energy transfer from one laser beam to another.
If the photorefractive gain exceeds the absorption, then there is net optical amplification.
In one embodiment of the invention, the Group III-V material matrix and Group V inclusions are comprised of LTG GaAs:As or LTG AlGaAs:As.
In other embodiments of the invention the inclusions are comprised of Al or Cr.
In a further embodiment of the invention the matrix is comprised of Ge and the inclusions are comprised of Ni
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Optical Systems 
