Nucleon mass from a covariant three-quark Faddeev equation.

We report the first study of the nucleon where the full Poincaré-covariant structure of the three-quark amplitude is implemented in the Faddeev equation. We employ an interaction kernel which is consistent with contemporary studies of meson properties and aspects of chiral symmetry and its dynamical breaking, thus yielding a comprehensive approach to hadron physics. The resulting current-mass evolution of the nucleon mass compares well with lattice data and deviates only by ∼5% from the quark-diquark result obtained in previous studies.

Fast optical binary multiplication using a sign/logarithm number system.

A new fast binary multiplication scheme based on a nonholographic optical content-addressable memory (CAM) is presented. By using a sign/logarithm number (SLN) system, the multiplication operation is performed through a binary logarithmic addition. A three-stage CAM-based multiplication scheme is proposed in which the first CAM converts input binary numbers to SLN's, the second CAM performs a fixed-point binary addition, and the third CAM converts this SLN result back to the binary number system. The design and experimental demonstration of a 7-bit nonholographic optoelectronic CAM-based multiplier are presented.

Detection of multipath effect using a self-pumped optical phase-conjugate filter.

A new optical Fourier domain filtering scheme that combines the conventional optical space-invariant linear filtering with a self-pumped nonlinear-optical phase-conjugation technique is proposed. The new method is used for a real-time detection and channel evaluation of the multipath information needed in radar, sonar, and communication signal-processing applications. Preliminary experimental demonstrations are included.

Fast digital optical multiplication using an array of binary symmetric logic counters.

Because of the lack of fast, accurate, and large dynamic range analog-to-digital converters (ADCs), optical implementation of the digital multiplication through analog convolution (DMAC) algorithm yields a slow digital multiplier. By replacing both the optical adder and ADC arrays by an optical combinatorial logic counter array, a new optical fast digital multiplication method is proposed. Compared to the existing optical DMAC scheme, the new method promises both higher processing speed and accuracy. A comparison of this and some of the other optical and electronic fast digital multiplication schemes is also presented.

Free-space optical collinear crossover interconnects.

Two new optical free-space collinear cross-over interconnect schemes are suggested. The first optical implementation uses mirrors and beam splitters, while the second uses a Fresnel zone plate and lens combination. Some proof-of-principle experimental results are also presented.

Fast hybrid parallel carry look-ahead adder.

A new optical parallel arithmetic processing scheme using a nonholographic optoelectronic content-addressable memory (CAM) is discussed. The design of a four-bit CAM-based optical carry look-ahead adder (CLA) is presented. Compared with existing optoelectronic binary addition approaches, this nonholographic CAM scheme offers a number of practical advantages, such as faster processing speed and ease of optical implementation and alignment. For the addition of numbers longer than four bits, by incorporating the previous stages' carry, a number of four-bit CLA's can be cascaded. Experimental results are also presented.

Optical higher-order symbolic recognition.

Several new higher-order spatial symbol recognition methods for optical symbolic substitution-based calculations are presented. In the case of logic processing, higher-order symbolic substitution (SS) rules can implement multivariable logic functions. For binary arithmetic calculations requiring carry propagation by simultaneously processing a number of bits, the computational speed increases. Finally, in image processing, the higher-order SS rules allow the use of larger local windows. For a higher-order spatial symbol recognition, both multiplicative and additive logic techniques are discussed. Four different higher-order SS recognition optical architectures are suggested: a multireflecting technique using an optical cavity, a lenslet array, an optical phase conjugation, and a content-addressable memory. Either dual-rail or triple-rail optical spatial intensity encoding is employed. Some preliminary experimental results are also presented.

Compact parallel real-time programmable optical morphological image processor.

Based on the parallel-processing and interconnection capabilities of optics, a novel, compact, real-time programmable parallel optical morphological filter is proposed and demonstrated. Using a real-time polarization-encoded image-casting scheme, some proof-of-principle experimental results are presented.

Content-addressable-memory-based single-stage optical modified-signed-digit arithmetic.

Using a novel nonholographic optoelectronic content-addressable memory in a free-space angular multiplexing geometry, a single-optical-stage compact parallel optical modified-signed-digit arithmetic processing architecture is proposed. Some spatial light modulator based experimental results are also presented.

Optical parallel register transfer microoperations using holographic symbolic substitutions.

Optical register transfer microoperations are proposed. Based on an optical holographic associative symbolic substitution, a hybrid optical word-parallel bit-serial register transfer processor architecture is described. Preliminary experimental results are included.

Liquid crystal TV-based white light optical tracking novelty filter.

A compact white light optical tracking novelty filter is demonstrated. Based on the use of two inexpensive liquid crystal televisions, a filtered and collimated white light source, digital delay, and video recorder, this portable white light device performs two major image comparison operations, a real time image subtraction and novelty tracking operations. Some preliminary experimental results are presented.

Optical on-the-fly conversion of a modified signed digit into two's complement binary number representation.

An optical carry-free technique is introduced for conversion of a modified signed digit (MSD) into two's complement binary number. Using a combination of optical polarizing beam splitters and retardation waveplates, the proposed device performs this conversion on the fly. The availability of this converter will lead to a large speed increase for various proposed optical parallel MSD arithmetic processors.

Parallel optical pyramidal image processing.

Pyramidal processing is a form of multiresolution image processing in which the image is decomposed into a sequence of images at different resolutions. Pyramidal processing aims to extract and interpret significant features of an image at different resolutions. Digital pyramidal image processing, because of the large number of convolution- type operations, is time consuming. On the other hand, optical pyramidal processors, described here, are preferable in real-time image-understanding applications because of their ease in performing convolution operations. Preliminary experimental results for optical Gaussian and Laplacian pyramidal image processing are presented.

Free-space folded-path optical programmable logic array.

A new method to realize a medium-scale, free-space optical programmable logic array is proposed. By using either a two-dimensional optical spatial light modulator or an array of one-dimensional spatial light modulators inside a lens-based multiple-beam-path cavity, an array of optical multiple-variable logic product terms is generated. This device, together with a programmable multiple-variable OR matrix, can be used to implement any Boolean combinatorial logic operations. For an optical binary combinatorial logic computation, the proposed method efficiently uses three-dimensional space and optical elements. Preliminary experimental results obtained using an inexpensive liquid-crystal television are included.

Optical implementation of binary symmetric logic functions.

Optical implementations of binary multiple-variable symmetric logic functions are proposed. By using a triangular array of lossless beam splitters together with optical on-off switches, an optical binary symmetric logic module (OBSLM) is experimentally implemented. The applications of the OBSLM to optical digital, symbolic, and neural computing are discussed.

Parallel digital and symbolic optical computation via optical phase conjugation.

The use of the optical phase conjugation (OPC) process for parallel digital and symbolic optical computing is described. Using spatially encoded logic and symbolic variables, various OPC-based parallel ultrafast optical logic, symbolic as well as interconnect processors are detailed. The proposed devices are experimentally verified using picosecond pulses from a mode-locked Nd(3+):YAG laser. Based on these processors, an OPC-based ultrafast optical computing architecture is proposed.

Optical parallel image skeletonization using contentaddressable memory-based symbolic substitution.

In this paper, two optical image skeletonization algorithms are introduced. In both algorithms, the matching between an input and a set of precalculated parallel check patterns is performed. Based on the matching results, multistage symbolic substitution operations are incorporated. For an optical implementation, an optical hologram-based content-addressable memory technique is employed. The corresponding optical architecture as well as character skeletonization examples are presented.