BIOMEDICAL ARTICLES
Digital holographic data storage in a high-performance photorefractive polymer composite.
Binary information in the form of a 256 x 256 pixel array has been stored holographically within a polymeric photorefractive composite of 130-mum thickness. Devices used consisted of 55-wt. % organic chromophore 1-(2?-ethylhexyloxy)-2, 5-dimethyl-4-(4?nitrophenylazo) benzene and up to 11.2-wt. % 2, 4, 7-trinitro-9-fluorenone […]
Storage density of shift-multiplexed holographic memory.
The storage density of shift-multiplexed holographic memory is calculated and compared with experimentally achieved densities by use of photorefractive and write-once materials. We consider holographic selectivity as well as the recording material\’s dynamic range (M/#) and required diffraction efficiencies in formulating the calculations of storage densities, thereby […]
Substrate noise in optical data-storage systems.
Noise in optical disk readout has been examined for different polarizations of the incident beam. The disks studied are bare grooved glass substrates, having different groove shapes or differing jaggedness in the sidewalls. We perform measurements for the electric field of the incident laser beam parallel to […]
Parallel optical interconnects may reduce the communication bottleneck in symmetric multiprocessors.
We start with a detailed analysis of the communication issues in today\’s symmetric multiprocessor (SMP) architectures to study the benefits of implementing optical interconnects (OI) in these machines. We show that the transmission of block addresses is the most critical communication bottleneck […]
Two-beam Coupling Modules for Photorefractive Optical Circuits.
Modules that perform photorefractive two-beam coupling operations have been built, characterized, and tested. These portable modules, interconnected by fiber optics, dispense with the need for repeated alignment and greatly facilitate the prototyping of complex signal- or image-processing photorefractive circuits. To evaluate the performance of the modules […]
Enhancement of Two-Wave Coupling in a Ce:KNSBN Crystal with Optimum Polarization of the Writing Beams.
We have improved the two-wave coupling amplification and the signal-to-noise ratio of an amplified signal with photorefractive cerium-doped potassium sodium strontium barium niobate (Ce:KNSBN) by employing optimum polarization orientation of the pump beam while the signal beam retains […]
Volume-scanning three-dimensional display that uses an inclined image plane.
A novel three-dimensional display based on a volume-scanning method that uses an inclined light-source array and a mirror scanner is proposed. With this technique it is possible to display three-dimensional images that satisfy all factors for human stereoscopic vision. Three-dimensional images of 8 x […]
Hidden images in halftone pictures.
A method of concealing an image in a different halftone image is proposed. Continuous-tone levels of the visible images are represented by the area of the halftone dots. However, the hidden image is encoded by the dots\’ positions inside their cells. Only a spatial correlator with a unique […]
Full- and minimal-scan reconstruction algorithms for fan-beam diffraction tomography.
Diffraction tomography (DT) is a tomographic inversion technique that reconstructs the spatially variant refractive-index distribution of a scattering object. In fan-beam DT, the interrogating radiation is not a plane wave but rather a cylindrical wave front emanating from a line source located a finite […]
Large-scale three-dimensional object measurement: a practical coordinate mapping and image data-patching method.
In a practical three-dimensional (3-D) sensing system, the measurement of a large-scale object cannot be completed in only one operation. A relieflike object is generally divided into several subregions, an optical sensor positioned at each of these locations, and the shape […]
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