USA As Represented by Secretary of the Navy

Larry B Stotts

Paul S Catano

Michael A Monahan

Richard P Bocker

William H McKnight

Keith Bromley

William E Martin

Gregory C Mooradian

A true indication of a fluid's absorption coefficient takes into effect the contributing factors of absorption and particle multiple scattering. A pulsed optical source transmits radiation through a relatively large volume of a certain particulate fluid medium. A detector or irradiance meter is gated so as to provide waveforms on a monitor which are characteristic of the absorption and multiple scattering of the medium. Using the transmittance and multiple line spread of the received signal a nearly real-time in situ analysis can be performed to provide scientists, communications specialists, etc. with the capability to anticipate operational parameters.

Method for determining in situ the absorption coefficient of particulate

A visual display has an increased readout capability due to its operation the transflective mode. A source of ambient light and light for radiation through the display from the backside together assure the increased readout capability. Heretofore, ambient light would degrade or washout a display making it nearly impossible for monitoring personnel to decipher alphanumeric or pictoral displays due to the decreased contrast. A pair of linear polarizers sandwich a twisted nematic liquid crystal and have their polarization axes either parallel or mutually orthogonally disposed so that the crystal will present bright or dark areas in response to applied potentials. Because a partially transmitting mirror is interposed between the sandwiched liquid crystal and the radiating light source, the ambient light augments the radiated light to enhance the visual display.

Transmissive and reflective liquid crystal display

An improved optical element is provided by an arrangement of optical wavedes disposed with two photoconductive paths and a plurality of electrodes arranged to impress an electric field across the optical waveguide configuration and the photoconductive paths. Optical energy is fed into an input optical waveguide and, dependent upon the optical inputs to the first and second photoconductive paths, an output is produced by the optical waveguide configuration in the manner of a logic gate. Variant configuration of the optical waveguide assembly can be made to perform in the manner of an AND gate, and OR gate, an exclusive OR gate, a NOR gate, or a NAND gate; alternatively, combination configurations can simultaneously perform multiple logic functions.

Optical logic elements

An optical waveguide of photoconductive material is positioned parallel to t least one other optical waveguide of electrooptical material. A first electrode is positioned between the two optical waveguides and second and third electrodes are positioned contiguous to the optical waveguides and opposite the first electrode. A constant amplitude electrical source is connected to the second and third electrodes and when light energy signals representative of a column vector function are propagated along the photoconductive optical waveguide, a commensurate change of conductivity between the first and second electrodes is caused to occur with a consequent change in electrical potential across the second and third electrodes embracing the optical waveguide of electrooptic material. When light energy signals representative of a row vector function are propagated along the second optical waveguide, a polarizatin modulated output signal is developed by the second optical waveguide. A polarization analyzer of the filter or polarization discriminator type intercepts the polarization modulated output light signals of the second optical waveguide and an integrating storage detector responds to the output light signals for generating commensurate electrical signals which are representative of the multiplication of the column vector function and the row vector function as represented by the light energy signals propagating along the photoconductive optical waveguide and the electrooptical waveguide, respectively. By adding several electrooptical waveguide, analyzer, and detector sections in electrical parallel to the first electrooptical subsystem, the row-column vector multiplier is made to function as a matrix vector multiplier.

Integrated optical matrix multiplier

An electro-optical system for performing matrix-vector multiplication includes a mask having a plurality of elements of substantially equal resolution area disposed in a matrix of M rows and N columns, each element containing recorded discrete information as defined by its degree of opacity which is representative of a predetermined mathematical value in a known matrix. A light source is positioned to illuminate the mask and has its intensity modulated as a function of the sequential values in a N X 1, vector. A multiple photo-responsive array including M elements disposed in a column is positioned to receive the light energy transmitted by the illuminated mask and generates signals at each element commensurate with the instantaneous photo energy received at its position. A suitable means which is synchronously operative with the modulation of the intensity of the light source, sequentially develops cumulative signals corresponding to the signal information contained in each column of the mask, producing a matrix-vector multiplication result.

Electro-optical system for performing matrix-vector multiplication

Matrix-vector multiplication is accomplished by continuous wave polarized ght energy transmitted along a plurality of optical waveguides through modulation by a first optical modulator in response to a column vector type input signal and additional modulation by a second optical modulator in response to a row vector type input signal. The resultant modulated light energy outputs are received by a polarization analyzer for transforming modulations in polarization and phase to commensurate amplitude modulations. A photo-responsive storage and integrating means receives the light energy associated with each of the optical waveguides and develops a cumulative signal representative of the matrix-vector multiplication.

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Chula Vista, CA, United States of America

Larry B Stotts