USA As Represented by Secretary of the Navy

Ray B Brown, Jr

John N Lee

Robert L Denningham

A light beam encoded with data simultaneously reads out data stored in tracks on an optical disk and produces a reflected beam directed to a detector array. The data stored on the optical disk and the encoded data may be components of vector arrays. As the light beam illuminates the rotating optical disk, the data stored on the disk is multiplied by the encoded data. The products of the multiplication are encoded in the reflected beam. A multiplicity of data is read out in parallel from the optical disk and simultaneously correlated with the encoded data. This comparison or correlation operation is performed on digitally encoded data utilizing convolution, or with analog encoding. The present invention can be utilized in pattern matching.

Method and apparatus for parallel readout and correlation of data on optical disks

A common-path interferometric acoustic-optic heterodyne spectrum analyzer ving high immunity to ambient vibration uses two, counter-propagating beams, two Bragg cells for beam diffraction, a series of waveplates and a birefringent quartz wedge. Proper light polarization with the waveplates and Bragg cell geometry allows one Bragg cell to diffract primarily the clockwise beam and the other Bragg cell to diffract the counterclockwise beam. The birefringent quartz wedge shifts the diffracted beams to provide a heterodyne signal with a non-zero IF carrier frequency. The analyzer is highly angle compensated and alignment stable when components are disturbed in position or orientation.

Optically stable, large time bandwidth acousto-optic heterodyne spectrum

An improved variable light beam power attenuator which uses a flat mirror d a focusing mirror fixed in a suitably movable structure. Linear movement of this structure varies the diameter of a spot of light illuminating a 'diffraction-limited' aperture of a special shape. A second focusing mirror is provided to collect the 'diffraction-limited' light transmitted by the aperture and to focus or collimate it. A second flat mirror may be used to re-direct the output beam. The mounting arrangement of the first two mirrors relative to the input light beam and the remainder of the power attenuator permit an all mirror system which requires only a single linear motion to change the power level of the transmitted beam. The use of an all-mirror system allows all the advantages of reflective optics over transmitting optics for high power CW (continuous wave) laser beam.

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Upper Marlboro, MD, United States of America

Ray B Brown, Jr