US 5,488,504 AGranted

Hybridized asymmetric fabry-perot quantum well light modulator

AssigneeMartin Marietta Corporation

InventorsTerrance L. Worchesky, Kenneth J. Ritter

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Abstract

A device for converting a set of electronic signals that represent an image into a coherent image includes a two-dimensional array of asymmetric Fabry-Perot (ASFP), quantum-well-based optical modulators connected on a pixel-by-pixel basis to a two-dimensional array of drive circuits located on an integrated circuit. Electronic signals received by the integrated circuit cause the pixel drive circuits to change a bias voltage applied across the optical modulator section and, thereby, change the optical properties of the optical modulator section of the device. The two-dimensional array can be used to impart intensity-only, phase-only, or phase-and-intensity variations onto a beam of coherent laser light incident on the array. This coherent image can be used with other optical elements to form optical processing machines and optical storage devices.

A spatial light modulator including quantum wells and Fabry-Perot etalons, comprising:

(A) a transparent non-semiconductor dielectric substrate having a first composition transparent to photons within a particular energy range, and having a first index of refraction;
(B) said spatial light modulator further including a plurality of modulator pixels responsive to said photons within said particular energy range, each of said pixels comprising:
(1) a partially reflective dielectric mirror and common electrical contact layer adjacent to said transparent substrate, said dielectric mirror and common electrical contact layer comprising (a) a first layer of a first semiconductor material, having an index of refraction higher than that of said transparent substrate, said first layer of said first semiconductor material being adhesively affixed to said transparent substrate, whereby the junction between said transparent substrate and said first layer of said first semiconductor material is a relatively wavelength independent mirror, said dielectric mirror and common electrical contact layer further comprising (b) a plurality of additional layers, at least one of which is electrically conductive, said additional layers including alternating layers of a second semiconductor material and said first semiconductor material, said second semiconductor material having an index of refraction lower than that of said first semiconductor material;
(2) a quantum well layer supported by that side of said dielectric mirror and common electrical contact layer remote from said first layer of said dielectric mirror and common electrical contact layer, said quantum well layer including a plurality of alternating layers of (a) third semiconductor material having a particular ground energy state, and (b) a further semiconductor material having a ground energy state higher than said particular ground energy state, whereby said quantum well layer includes a plurality of quantum wells;
(3) an optically non-transmissive metallic mirror layer;
and
(4) means for mechanically and electrically coupling said metallic mirror layer to said quantum well layer;
said modulator further comprising:
(C) an electronics section including drive electronics for generating a plurality of individual electrical drive signals;
and
(D) coupling means coupled to said drive electronics, to said electrically conductive layer of said dielectric mirror and common electrical contact layer, and to said metallic mirror layers of said pixels of said modulator, for coupling each of said individual electrical drive signals to said metallic mirror layer of a different one of said pixels.

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Abstract

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