Gte Laboratories Incorporated

Mario Dagenais

Wayne F Sharfin

Robert J Seymour

Boris S Elman

The I.sub.2 bound exciton in cadmium sulfide (bound to a neutral donor) is a very efficient radiator, providing low switching energy and fast switching times for an ON and OFF optical bistable device, desirable for all-optical signal processing applications. The optical bistable device for light at a given wavelength includes a Fabry-Perot cavity having a pair of opposed mirrored surfaces. A direct bandgap semiconductor, such as CuCl, CdSe, CdS, and GaAs having a bound exciton, is located within the cavity. The cavity is tuned near resonance of the light. The bound exciton has a coefficient of absorption tuned near resonance. A light beam of varying intensity is applied from without the cavity to one of the surfaces. The semiconductor has both an index of refraction and a coefficient of absorption that vary with the magnitude of applied light. Thus, light applied thereto passes through the device either substantially unimpeded or impeded, dependent upon its magnitude.

Optical bistable devices based on bound exciton nonlinearity

An array of bistable devices includes a thin cadmium sulfide platelet having a first portion thereof that is substantially pure and the remaining portion thereof is implanted with atoms that can bind excitons. Such remaining portion can be implanted with ions from a lithium source. Apparatus for providing such an array can include a source of lithium ions and masking means for selectively permitting and for selectively inhibiting passage of ions from the source to pass therethrough and to implant in a pattern onto the platelet. The apparatus operates at temperatures in the neighborhood of liquid helium. A method for producing such an array includes providing a thin, substantially pure, platelet of cadmium sulfide, selectively masking the platelet with a pattern to selectively permit and to selectively inhibit passage of ions onto the platelet, and providing a source of ions. The source of ions, in accordance with certain features, can be lithium ions.

Array of bistable devices and apparatus and methods for creating same

Real-time all-optical multiplication of an n component vector by a large m by m matrix having digital accuracy utilizes an updatable two dimensional spatial light modulator.

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Wellesley, MA, United States of America

Mario Dagenais