USA As Represented by Secretary of the Navy

United States of America As Represented by the Secretary of the Air Force

Other

US Government As Represented by the Secretary of the Army

Pankaj K Das

Julius Frankel

Agostino Abbate

Harry F Tiersten

John F McDonald

Daniel Litynski

Barry L Shoop

Bijan Davari

A method of converting an analog signal to a digital signal includes (a) filtering the analog signal to the range 0&lE;f &lE;f ; (b) sampling the filtered signal at a rate f >>f , where f is the sampling frequency, f &equals;2f is the Nyquist frequency of the sampled signal, and f &lE;f /2 is the constrained signal bandwidth; (c) converting the sampled signal to an optical sampled signal: (d) converting the optical sampled signal from a temporal signal to a spatial signal; (e) illuminating a smart pixel array with the spatial signal; (f) processing the spatial signal with an error diffusion neural network to produce a 2-D binary image; and (g) averaging rows and columns of the 2-D binary image using a digital low pass filter and a decimation circuit.

Photonic analog to digital conversion based on temporal and spatial oversampling techniques

An apparatus and/or system is described which uses the photocharge voltage concept in lieu of optical scattering techniques to measure surface topology and properties of materials. The system is based on the measurement of a small electrical potential difference which appears on any solid body when subjected to illumination by a modulated laser light. This voltage is proportional to the induced change in the surface electrical charge and is capacitively measured on various materials. The characterization of coatings to be used inside the base of guns is just one possible application for use by the U. S. Army.

Photocharge microscope

Apparatus and method for selectively controlling anodic oxide growth on semiconductors for controlled electrochemical pattern generation incorporating use of a writing beam of a wavelength which encourages oxide growth and a bias beam at a wavelength which discourages oxide growth. The bias beam is projected on the semiconductor in electrolytic environment to prevent or retard oxide growth while oxide growth is accelerated at points of illumination by means of writing beam.

Selective anodic oxidation of semiconductors for pattern generation

In-situ, non-destructive monitoring of semiconductors during laser annealing process is realized by a method the steps of which include: positioning a surface acoustic wave device adjacent to the semiconductor being annealed and in intercepting relationship with the annealing radiation, the surface acoustic wave device substrate being transparent to the annealing radiation; affixing an electrical contact to the top surface of the semiconductor; applying an r.f. input to the surface acoustic wave device; and measuring the transverse acousto- electrical voltage on the electrical contact. The surface acoustic wave propagation surface of the surface acoustic wave device is in close proximity to the bottom surface of the semiconductor and interaction of the electric field that accompanies the propagating surface acoustic wave with the charge carriers of the semiconductor produces the transverse acoustoelectric voltage. The transverse acoustoelectric voltage is thus a function of the semiconductor conductivity.

Method for providing in-situ non-destructive monitoring of

A transducer array comprising a large number of separated sets of electrodes plated on a single piezoelectric plate of uniform thickness is described. Each set of electrodes is made to act essentially independently by placing them sufficiently far apart and employing an essentially trapped energy mode.

Monolithic mosaic piezoelectric transducer utilizing trapped energy modes

An acousto-optic image scanner employing pulses of acoustic surface waves which propagate along the length of a piezoelectric crystal performing as a traveling phase grating to diffract a collimated monochromatic light beam which has a spatial light distribution corresponding to the information content of a line of the image. The light beam propagates through the width of the crystal thus providing an extensive electro-optic interaction length for increased diffraction efficiency. The light intensity at a first-order spot is detected to provide a temporal signal representative of the light distribution of an image line. Scanning of colored images can be accomplished by utilizing a chromatic beam and detecting the light at the first-order spots corresponding to the three different wavelengths present in the illuminating beam.

Growing community of inventors

Cohoes, NY, United States of America

Pankaj K Das