Abstract: An extremely high resolution holographic lens is provided, comprising an interference pattern between light emitted from at least one tiny point source of light such as the tip of an optical fiber, having a diameter in the nanoscale region, and at least one plane or quasi-plane broad light beam. The holographic lens is employed for example in pickups for reading data off of, and writing data upon terabit optical storage mediums and nanoscale resolution microscopic media.

Abstract: A single high resolution holographic pickup, for reading/writing both a CD and DVD optical recording medium, has an electrical tuning control for applying a DC and AC signal to a tunable Bragg cell, which AC is phase locked with respect to the fundamental repetition frequency of the recorded data on the CD to produce accurate tracking. A special high resolution holographic lens is recorded within the Bragg cell that focuses the light signals read off of the optical storage mediums upon a pickup detector, and its focal length is varied to read a selected CD and or DVD from a group of CDs or DVDs in response to changes in the DC applied to the Bragg cell. The holographic lens within the Bragg cell is formed by an interference pattern produced by interfering light emitted from the tip of a one micron optical fiber and a plane broad light beam.

Abstract: An oscillating microscopic or tomographic optical input image is directed at a tunable Bragg cell and a tuning control device applies a fluctuating AC hetrodyne signal to the cell, such signal having a phase locked template with respect to oscillation of the optical image, causing the cell to hetrodyne and correlate a phase locked matching template with the oscillating optical input image. A time integrating detector integrates output signals from the Bragg cell while illuminated point sources of the optical image are interconnected with corresponding imaging points upon the integrating detector via a high resolution holographic lens array within the Bragg cell. The array consists of recorded interference patterns between tiny one micron point sources of light produced by an optical fiber with broad wave fronts of light. A DC signal applied to the Bragg cell along with the AC signal enables beneficial wavelength discrimination and averaging.

Abstract: An oscillating microscopic or tomographic optical input image is directed at a tunable Bragg cell and a tuning control device applies a fluctuating AC hetrodyne signal to the cell, such signal having a phase locked template with respect to oscillation of the optical image, causing the cell to hetrodyne and correlate a phase locked matching template with the oscillating optical input image. A time integrating detector integrates output signals from the Bragg cell while illuminated point sources of the optical image are interconnected with corresponding imaging points upon the integrating detector via a high resolution holographic lens array within the Bragg cell. The array consists of recorded interference patterns between tiny one micron point sources of light produced by an optical fiber with broad wave fronts of light. A DC signal applied to the Bragg cell along with the AC signal enables beneficial wavelength discrimination and averaging.

Abstract: A single high resolution holographic pickup, for reading/writing both a CD and DVD optical recording medium, has an electrical tuning control for applying a DC and AC signal to a tunable Bragg cell, which AC is phase locked with respect to the fundamental repetition frequency of the recorded data on the CD to produce accurate tracking. A special high resolution holographic lens is recorded within the Bragg cell that focuses the light signals read off of the optical storage mediums upon a pickup detector, and its focal length is varied to read a selected CD and or DVD from a group of CDs or DVDs in response to changes in the DC applied to the Bragg cell. The holographic lens within the Bragg cell is formed by an interference pattern produced by interfering light emitted from the tip of a one micron optical fiber and a plane broad light beam.

Abstract: A single tunable filter WDM Bragg cell is employed to both wavelength demultiplex and detect incoming light beams by the application of a DC tuning signal for wavelength selection, together with an AC component for facilitating detection of data impressed upon selected incoming demultiplexed beams, all in the optical domain, in contrast with the electrical domain, to enhance processing speed. The AC component can perform hetrodyne detection for TV and telephone analog communication systems, or can detect digital signals for DSL internet communication systems, and cost savings result from the use of a single compact cell tuned by the composite signal permitting demultiplexing and detecting in one cell component. The resulting versatility enables use of the single cell in WDM and TDM, WDM and spread spectrum, and WDM packet switching and TCP/IP header digital address recognition systems.

Abstract: A first lens produces a Fourier transform of the wavefront distorted optical image at the Fourier transform plane. A phase encoded filter is positioned at the transform plane and a second filter is tandemly positioned with respect to the first filter, the second filter having a transmittance which is statistically similar to the reciprocal spatial frequency spectrum of the Fourier transform of the distortion function, to in turn produce an intermediate signal at the transform plane, which is now Fourier transformed by a second lens to recover the optical image having a substantially reduced degree of distortion.

Abstract: A spectrum analyzer for producing a first two-dimensional array of time varying spectral analysis image input signals, a reference image generator for producing a second two-dimensional array of spectral analysis image reference signals, and a time-integrative correlator, which can be non-coherent or coherent, or correlating the two groups of image representitive signals to determine the degree of matching between an input image and a library reference image. The spectrum analyzer can include an interferometer, a tunable optical filter, or a time-wavelength-multiplexing holographic lens for viewing the input image. A monolithic non-holographic version provides a rugged, compact and portable image analyzer for examining many types of images.

Abstract: A holographic grating is written into a photorefractive erasable holographic member and a light beam having a first wavelength which includes the joint power spectrum of a pair of joint images to be correlated is directed at the photorefractive member to partially erase the grating. A phase conjugate signal from the partially erased grating is then readout and Fourier transformed to produce the correlation output spots.

Abstract: An all optical photorefractive holographic joint transform correlator provides a first correlation plane output port using two-beam coupling, and a second correlation plane output port employing four-wave mixing. With appropriate input beam intensity ratios, the first port output is capable of high discrimination, while simultaneously the second port offers a low discrimination output.

Abstract: Image derogating optical noise due to light scattering of an object under examination, embedded in a light scattering medium, is substantially reduced by passing a modulated signal laser beam through the scattering medium, and interfering the emerging signal with a coherent modulated reference beam to produce a hologram in a photorefractive member of the object, which in turn is read out of the crystal by a third unmodulated coherent beam to retrieve a clear image of the object. A smart pixel image convertor light valve may be substituted for the photorefractive member.

Abstract: Image derogating optical noise due to light scattering of an object under amination, embedded in, or positioned in front of a light scattering medium, is substantially reduced by employing a two-dimensional all optical phase sensitive holographic detector and vibrating the light scattering material at an ultra-sonic frequency to produce both signal sidebands and noise sidebands. Homodyne and hetrodyne techniques are used to filter out sidebands due to the light scattering noise and pass the desired signals, thereby to output a clear image of the object free of optical scatter noise. A smart pixel image converter light valve may be substituted for the photorefractive member.

Abstract: Limiting quadratic processing and compansion in photorefractive two beam coupling is disclosed. Two-beam coupling in photorefractive barium titanate employs the imaged intensity of the signal to amplify the reference beam while maintaining the phase of the reference beam. The phase distorted signal beam is converted to that of the controlled phase of the reference beam. The high pump limit of amplification in this two-beam coupling device produces an amplitude compressed output to reduce multiplicative noise. Lost contrast of the image is thereafter restored. Beam clean-up of a non-intelligence bearing beam can be carried out by a similar process; a low pass filter consisting of a pinhole plate can be used in place of the second photorefractive crystal in the Fourier plane and only the planar wavefront portion will pass through the pinhole and may be collimated by a lens to provide a cleaned planar output beam.

Abstract: An object beam is passed through an aberrating medium to produce a diffraction distorted image therein, which is imaged upon a spatial light modulator. A probe beam measures the phase aberrated wavefront within the aberrating medium and is used to produce an interference pattern which is employed to produce phase encoding signals to be fed back to the spatial light modulator for compensating in part for the phase distortion of the phase aberrated wavefront. The result is an output image having a substantially reduced degree of distortion.

Abstract: A joint transform correlator has modulators for temporally modulating a first optical input signal at a first frequency and a second optical input signal at a second frequency. An image sensor in the Fourier plane forms a product signal modulated by temporal sum and difference frequencies of the first and second frequencies. The product signal is thereafter demodulated at the temporal sum or difference frequency and the resulting optical signal is inverse Fourier transformed to recover the desired cross correlation signals.

Abstract: An all-optical nonlinear joint transform correlator has been implemented for the first time without using a spatial light modulator and digital processing in the Fourier plane. The correlator utilizes energy transfer from two-beam coupling in the Fourier plane. A compressional nonlinearity in the hard-clipped regime is implemented by pumping a weak plane wave with the intense joint spectrum of the reference and signal images. Operation of this device rivals or exceeds that of the phase-only filter for detecting objects in cluttered noise. Experimental results are compared with both plane wave and beam propagation simulations.