Rockwell International Corporation

Teledyne Scientific and Imaging, LLC

Tallis Y Chang

Jian Jim Ma

Bruce Kevin Winker

Bing Wen

Pochi A Yeh

Mohsen Khoshnevisan

John H Hong

Dong-Feng Gu

Jack L Feinberg

Mark D Ewbank

Arthur E Chiou

Sung J Choi

This disclosure relates to a real-time, hybrid amplitude-time division polarimetric imaging camera used to derive and calculate Stokes parameters of input light.

Real-time, hybrid amplitude-time division polarimetric imaging camera

A method is provided for reconstructing an image transmitted through a thick distorting medium. A remote source provides coherent light at the object plane, and a local source, typically derived from the remote source, provides corresponding light that is coherent with respect to the remote source. Light from the remote source is directed through the thick aberrator and into a holographic medium, such as a photorefractive crystal, to interact with corresponding light from the local source and produce a volume hologram. An angularly multiplexed volume hologram, which covers the entire object field, is written into the holographic medium by successive exposures of light from the remote and local sources for successive pixels of the object plane. Light from an object, which comprises two-dimensional information from the object plane, can be reconstructed by the volume hologram after being distorted by the thick aberrator. Light from each point of the object accesses the set of gratings in the volume hologram and reconstructs only the reference wave associated with it. Reconstructed waves emerging from the hologram are then focused by a following lens to form a high resolution image of the object at the image plane of the lens.

Image transmission through thick aberrators

An optical image enhancer includes a beam of coherent light for carrying an input image and a first lens for receiving the beam and performing a spatial Fourier transform of the input image. A photorefractive crystal at the Fourier plane receives the transformed image, while a coherent pump beam illuminates selected spatial frequency components of the transformed image at the Fourier plane, thereby transferring energy to the selected frequencies by two-beam coupling. A second lens receives the transformed image from the Fourier plane and performs a spatial Fourier transform of the transformed image, thereby reproducing the input image in an output image which contains intensified features corresponding to the selected spatial frequency components. A spatial light modulator may be used to cause the pump beam to illuminate the selected spatial frequency components of the transformed image at the Fourier plane. The pump beam can carry the Fourier transform of a selected portion of the input image, such that the intensity of the selected portion is increased in the output image.

Image enhancement techniques using selective amplification of spatial

A mutually pumped phase conjugator (MPPC) is used to remove spatial distortions from a high power laser beam. The high power beam with its 'dirty' spatial profile is directed into one side of the MPPC. A spatially clean beam at the same nominal frequency as the high power beam is output from a continuous wave (CW) laser and directed into the opposite side of the MPPC. As a result of mutually pumped phase conjugation, the MPPC returns a phase conjugate beam that retains the clean spatial profile of the CW beam but acquires the temporal characteristics of the high power beam. A Faraday isolation system may be used to separate the phase conjugate beam from the incident CW beam to provide an output beam having a clean spatial profile. If desired, the high power beam can be transformed into an image bearing output beam simply by modifying the incident CW beam with a transparency or spatial light modulator. If the average intensity of the dirty beam is much higher than that of the CW beam, only a small fraction of the dirty beam needs to be directed into the MPPC for beam clean-up. The larger fraction of the dirty beam can be directed into a photorefractive crystal for two-beam coupling with the clean beam output by the MPPC. By means of photorefractive two-beam coupling, energy from the dirty high power beam serves to amplify the clean beam, thereby improving the overall energy efficiency of the laser beam clean-up system.

Laser beam clean-up using mutually pumped phase conjugation

A phase-conjugate optical communication system includes a first source of coherent radiation for producing a first beam having a nominal wavelength .lambda. and a first modulator for temporally modulating the first beam. A second source of coherent radiation, mutually incoherent with the first source, produces a second beam having the nominal wavelength .lambda., while a second modulator temporally modulates the second beam. A mutually pumped phase conjugator is positioned such that the first and second beams fan in the conjugator and produce a set of shared fanning holograms, the holograms causing a third beam, which is the phase conjugate of the first beam and on which is imposed the temporal modulation of the second beam, to be diffracted in a direction opposite to the first beam and causing a fourth beam, which is the phase conjugate of the second beam and on which is imposed the temporal modulation of the first beam, to be diffracted in a direction opposite to the second beam.

Phase-conjugate communication using mutually incoherent laser beams

A phase conjugate interferometer for combining first and second two dimensional images includes a source of coherent light and a first beam splitter for dividing the coherent light into a transmitted beam and a reflected pump beam. A second beam splitter divides the transmitted beam into a reflected first probe beam which traverses a first image transparency and a transmitted second probe beam which traverses a second image transparency. A nonlinear optical medium receives the reflected pump beam, the first probe beam, and the second probe beam, with the medium, the pump beam, and the probe beams being oriented such that self-pumping of the reflected pump beam produces counterpropagating pump beams, four-wave mixing between the counterpropagating pump beams and the first probe beam produces a phase-conjugated first output beam which traverses the first image transparency, and four-wave mixing between the pump beam and the second probe beam produces a phase-conjugated second output beam which traverses the second image transparency. The second beam splitter, the first output beam, and the second output beam are oriented such that a portion of the first output beam is transmitted by the second beam splitter and combines with a portion of the second output beam reflected by the second beam splitter to produce a combined output beam containing the difference between the intensities of the first and second image transparencies.

Growing community of inventors

Woodland Hills, CA, United States of America

Tallis Y Chang