This PDF file contains the editorial “Editorial: Celebration and Recognition, The Kingslake Medal and Prize” for OE Vol. 33 Issue 08

Single crystals of thallium phosphorous selenide Tl₃PSe₄, were grown from the melt by the Bridgman method. The crystal quality was evaluated by optical and metallographic techniques. The crystals transmit radiation between 0.7 and 14 μm. Etchpit studies show that the crystals are free from inclusions and lamellar twins and exhibit a uniform cross-sectional etchpit density. Thallium phosphorous selenide crystals are biaxial and belong to the orthorhombic crystal class. A detailed design for the noncollinear acousto-optic tunable filter that uses Tl₃PSe₄ crystal is presented. Design of filters from this class of crystals facilitates control of the angular aperture, an important device parameter.

We briefly discuss two approaches for enhancing the resolution enhancement of range-Doppler images (including synthetic aperture radar and inverse synthetic aperture radar images). The first approach can be used in conjunction with current radar systems that use a fixed narrowband waveform to acquire target data. It measures Doppler shifts more accurately than the traditional fast Fourier transform based techniques. It performs well in low signal-to-clutter regimes regardless of the statistical structure of the clutter. The second technique assumes that the radar can transmit different waveforms that are matched to the imaging task under consideration. It is based on the fact that the most accurate reconstruction of a range-Doppler target density function from N waveforms and their echoes is obtained by transmitting the singular functions corresponding to the N largest singular values of two kernels derived from the target density. We discuss two strategies for selecting the radar waveforms. The first strategy uses fixed waveforms that act as approximate singular functions for the kernels corresponding to wide classes of target densities. The second strategy adaptively selects the transmitted waveforms by solving a simultaneous target classification and image reconstruction problem.

We demonstrate how a realistic scene with high spatial and spectral resolution can be synthesized from color aerial photography and AVIRIS hyperspectral imagery. A review of techniques for image fusion is first presented. Image processing techniques were developed to extract a digital elevation model from stereo aerial photography in order to correct temporal shading differences between two image sets and to fuse aerial photography with AVIRIS imagery. A unique contribution is the explicit inclusion of corrections for topography and differing solar angles in the fusion process. Color infrared photography and an AVIRIS image from a site near Cuprite, Nevada, were used as a test of an improved high-frequency modulation (HFM) technique for the creation of hybrid images. Comparison of spectra extracted from the synthesized image with library spectra demonstrated that our methodology successfully preserved the spectral signatures of the ground surface.

While a thin film with columnar microstructures is growing, a Motohiro-Taga interface is formed when the angle of inclination of the microstructures is abruptly altered in the vertical plane. Reflection of a normally incident plane wave by a Motohiro-Taga interface has been studied. If the plane wave is TE-polarized with respect to the plane contaming the directions of inclination of the columnar microstructures, it is not reflected by the interface; but a TM-polarized plane wave is partially reflected. Because of its polarization-discrimination property, the Motohiro-Taga interface will find application as the basis for devices in the upper millimeter wave and the lower infrared frequency ranges.

In the Relay Mirror Experiment (RME), three laser beams were propagated from ground to space and retroreflected from the RME spacecraft. An argon-ion beam at 488-nm wavelength and a Nd:YAG beam at 1064-nm wavelength were projected from a site at an altitude of 3050 m and an argon-ion beam at 514-nm wavelength was projected from a site 20 km away and at an altitude of 100 m. The beams had divergences ranging from 30 to 90 μrad. Uplink irradiances at the spacecraft and the retroreflected irradiances at the ground were measured. The data indicate that the uplink scintillation varies significantly within the Gaussian profile of the beams, and that the uplink scintillation is dominant in the retroreflected beams. The temporal spectrum of the scintillation shows a sharp roll-off beyond a characteristic corner frequency. The corner frequencies observed ranged from 400 to 700 Hz. The implications of the strength and temporal nature of the scintillation on fade statistics of the retroreflected beams are discussed.

The measurements of the ultraviolet response by some UV-enhanced CCDs have been realized. In particular, the quantum efficiency of coronene- and lumigen-coated and of back-illuminated ion-implanted CCDs have been measured in the 300 to 2500-Å spectral range. Very interesting performances have been found, mainly for one ion-implanted CCD with quantum efficiency values of more than 60% at 304 Å. Also some measurements of the CCD uniformity response and spatial resolution capability in this spectral region have been performed. The obtained results are very promising for the possibility of using these semiconductor detectors in the ultraviolet spectral region also with very good performance.

Motion-compensated coding, which exploits the temporal redundancies in the moving images, is one of the most popular techniques currently used. Recently, a variable block size (VBS) motion estimation technique has been proposed to improve the performance of the motioncompensated transform coding (MCTC). This technique allows larger blocks to be used when smaller blocks provide little gain, saving the bit rates especially for areas containing more complex motion. However, there have been few efforts to investigate an efficient VBS motion structure for reducing the motion vector coding rates further. Hence, a new VBS motion estimation technique based on a hierarchical structure is proposed that improves the motion vector encoding efficiency and reduces the number of motion vectors to be transmitted as well. Specifically, the gain/cost motion estimation technique with the selective motion prediction is utilized for the topmost level motion vector search, exploiting the redundancies among the neighboring motion vectors. Also, a restricted search with respect to the topmost level motion vector enables more flexible and efficient motion vector encoding for the remaining lower level blocks. Intensive simulation on several moving image sequences show that the MCTC employing the VBS motion estimation provides a performance improvement of 0.7 to 1.0 dB, in terms of peak SNR, compared with the fixed block size motion estimation.

The next generation of satellite-borne sensors will combine high spatial resolution with fine spectral resolution. A typical data set for a single frame of imagery may contain a few hundred images occupying many gigabytes of space. Clearly, traditional image processing algorithms cannot be directly applied to such a vast quantity of data. We investigate enhancement and compression algorithms that use the spectral correlation present in high-resolution imagery to reduce the computational complexity of processing the imagery. The algorithm employs a principal component transformation to reduce the size of the data set. Enhancing the reduced set of images provides equivalent results to processing each of the original images with far fewer computations. The compression algorithm utilizes a hybrid discrete cosine transform-differential pulse code modulation (DCT-DPCM) transform. The DCT is computed for each image, a bit map is generated for the DCT coefficients, and DPCM is used to encode the coefficients across the bands. Compression at less than 0.5 bits/pixel with negligible visual degradation is obtained.

A new image compression technique that uses what has been termed the "standard wavelet representation" of a function is presented. We show that this representation of an image leads to a subdivision of the frequency domain that is well structured and has smaller divisions than the "nonstandard wavelet representation" (multiscale decomposition) of a function. This allows for a more judicious selection of frequency information that may lead to better compression characteristics.

An efficient two-stage algorithm is presented for the synthesis of high-frequency-carrier diffractive elements. First, an on-axis phase-only stripe-geometry element with an unconstrained profile along each stripe is designed by an iterative Fourier transform algorithm. In the second stage, a steep linear phase term is added, and the profile is hard-clipped along each stripe. The result is a binary, pulse-frequency-modulated element suitable, e.g. , for a resonance-domain realization, which permits the elimination of the twin image. Experimental results are provided by direct-write electron-beam lithography and optical lithography, using both fully and partially coherent illumination.

The Mobile Imaging Spectroscopy Laboratory of the U.S. Army Research Laboratory was used to measure horizontal-path contrast transmission with 8- to 12-μm imagers in 1988. The values obtained were only about one-half of what was predicted by LOWTRAN7. In 1990 a large-area target board, 1.8 x 1.8 m, was used and resulted in resolvable temperatures that could be consistently measured over a 1.6-km path, even during times of strong optical turbulence, and were compared to 0.1-km reference temperatures to obtain values of contrast transmission. These new measurements compare very well with LOWTRAN7 calculations except for cases when aerosol attenuations from patches of ground fog and vehicular dust were present but not included in the calculations.

The optical and physical interconnection of optical fibers with optoelectronic devices is a critical technology in a wide range of telecommunication and data transmission applications. A new method of connecting optical fibers has been developed by "keying" a noncircular V-shaped optical fiber (V-fiber) into a silicon V-groove. In this interconnect the two resulting planes of contact provide enhanced lateral and rotational fiber alignment in comparison with conventional circular cross-section optical fiber and reduce the quantity of coupling agent required. The strength of the fibers and interconnects was evaluated by mechancal adhesion tests. Although the intrinsic V-fiber strength was less than that of conventional circular fibers, fiber/interconnect alignment was improved. Adhesion testing of interconnects indicated that V-fiber strength was the primary factor influencing interconnect strength. Low-light-loss splicing of V-fibers to conventional fibers has been demonstrated and allows circular fibers to be joined to V-fibers at interconnect points where improved alignment is required. V-fiber to V-groove interconnects have potential applications in multiple, birefringent, or small diameter core optical fibers.

An experimental setup was developed for time-gated (nanosecond) fluorescence spectroscopy and imaging of microscopic samples. This makes it possible to depict individual components of complex fluorophores and to measure specific metabolites on the basis of their decay times. The field of applications includes the selective detection of intrinsic fluorophores and of photosensitizers in single cells, skin, and teeth, as well as of photosynthetic pigments in plants under various stress conditions.

The Raman spectra of native lysozyme in aqueous solution and of lysozyme extracted by nitrobenzene have been obtained. The main- and side-chain conformation, relative change of intensities, and other properties of the lysozyme were studied. After nitrobenzene treatment, the various characteristic bands of the protein's main conformation appeared almost entirely at the original positions, indicating that there is no influence on the secondary-structure analysis of the protein.

Two expressions may be employed to calculate the value of the longitudinal focal displacement of the reflected beam from an absorbing medium for both s and p polarization. Our calculations show that F_p is positive (the p wave shifts along the reflected direction) and F_s is negative (the s wave shifts along the opposite direction). Assuming that the extinction coefficient is zero, then the two expressions can be simplified to the forms given by Chan and Tamir, which fit only for the nonabsorbing medium.

Several approaches to multichannel filtering for texture classification and segmentation with Gabor filters have been proposed. The rationale presented for the use of the Gabor filters is their relation to models for the early vision of mammals as well as their joint optimum resolution in time and frequency. In this work we present a critical evaluation of the Gabor filters as opposed to filter banks used in image coding-in both full rate and critically sampled realizations. In the critically sampled case, tremendous computational savings can be realized. We further evaluate the commonly used octave band decomposition versus alternative decompositions. We conclude that, for a texture segmentation task, several filters provide approximately the same results as the Gabor filter and, most important, it is possible to use subsampled filters with only a modest degradation in segmentation accuracy-realizing considerable computational savings.

We examine the correlation between subjective performance and objective image quality metrics, and show that an appropriately defined partial integral of the instrumental modulation transfer function (MTF), called MTFa, gives the best correlation with available psycho-physical data, including those obtained by other investigators. The Strehl ratio and the radius that encircles 84% of the point-spread-function energy also show some correlation with subjective performance, but have considerable limitations. These results begin to make real the possibility that the image quality of visual instruments may be characterized by a single figure of merit within the isoplanatic patch, for all types of monochromatic aberrations.

Ion-exchanged KTiOPO₄ (KTP) planar optical waveguides are formed in X, Y, and Z cuts of KTP single crystals with Rb⁺ -> K⁺, Cs⁺ -> K⁺, and Ag⁺ -> K⁺ ion exchanges from nitrate melts. Waveguide modes, index profiles, and birefringence of the waveguides are studied with the integrated optics technique. Electron probe microanalysis is applied to determine an elemental composition of the ion-exchanged structures and x-ray diffractometry is used to study crystalline structure of the waveguides. The research enabled us to produce KTP optical waveguides by silver ion diffusion for the first time. In addition, the residual potassium concentrations after the ion exchange are measured and the distribution profiles of Cs and Rb atoms and positions of the atoms in the KTP lattice are characterized. A study of the unit cell deformations accompanied by birefringence measurements enabled us to clarify differences in Rb⁺ -> K⁺ and Cs⁺ -> K⁺ ion exchanges. A novel approach that would produce a KTP optical waveguide with higher index increase and better crystalline perfection than Rb⁺ -> K⁺ and Cs⁺ -> K⁺ ion exchanges is proposed.

A technique is described for extending the resolution of an integrated optical multi-interferometer guided-wave analog-to-digital converter. The optical output waveform for each interferometer is symmetrically folded at twice a proper modulus. A small comparator ladder mid-level quantizes each interferometer's detected output to encode the analog signal in a symmetrical number system (SNS) format. By incorporating the SNS encoding, resolution greater than 1 bit per interferometer can be provided. Analog signal levels that can cause possible encoding errors are examined and their impact on the overall amplitude analyzing function is discussed. The maximum laser pulse width and maximum fluctuation in the sampling interval that can be tolerated is also discussed. Results indicate that 11-bit resolution can be provided with three interferometers and 39 comparators.

The Fourier transform moiré and grid method, which we previously presented, is extended to analyze strain distributions from the image of a fringe pattern with carrier fringes obtained by moiré interferometry. The characteristics of the carrier fringes and the procedure of obtaining strain distributions are explained in the spatial frequency domain. The fringe pattern without carrier fringes is obtained from the fringe pattern with carrier fringes by extracting the first harmonic of the spectrum of the fringe pattern with carrier fringes and shifting it. The strain distribution is obtained by analyzing the phase of the image obtained from the inverse Fourier transform of the shifted first harmonic. Strain distributions of a composite material with a wavy ply under compressive loading are analyzed.

A new modified moiré interferometry for measuring u, v, and w displacement fields is proposed. The method is actually integrated with in-plane moiré interferometry and a new interferometry that can attain out-of-plane displacements. The sensitivity of the measurement of the out-of-plane displacement is as high as a half-wavelength of the illuminating light. The measured in-plane and out-of-plane displacement fields are mutually independent and definitely defined.

We describe the use of a self-stabilized setup for timeaveraged holographic interlerometry recording of a vibrating surface in a perturbed environment. The hologram is recorded with the 632.8-nm wavelength of an He-Ne laser on a Bi₁₂TiO₂₀ crystal. The performance of the setup is discussed and experimentally evaluated.

A Talbot interferometer with circular grids is used to measure the temperature profile inside a premixed laminar flow slot burner used in an atomic absorption spectrophotometer. The experimentally measured results using the Talbot interferometry are compared with the values measured by a platinum-platinum-rhodium thermocouple with accuracy of measurement of ±0.2% full scale ±four digits and good agreement is found. The effect on the temperature profile of aspirating water through the nebulizer is also investigated.

A sinusoidal phase-modulating Fizeau interlerometer using a BaTiO₃ self-pumped phase conjugator is constructed to measure surface profiles of objects with a high accuracy. An object field is formed on a surface of a glass plate where the object wave interferes with its phase conjugate wave. Because the size of the glass plate can be much smaller than that of the object, the sinusoidal phase modulation by vibrating the glass plate is easy and accurate for measurements of the surface profiles of large-diameter objects. The interferometer is self-referencing and free of the phase fluctuations of the object wave caused by spatially uniform movements of objects. The usefulness of the interferometer is made clear through the surface profile measurements of a diamond-turned aluminum disk and mirror.

Nonreciprocity caused by temperature-rate-induced phase bias in fiber optic interferometers is experimentally investigated. A series of temperature ramp rates is applied to several fiber optic test coils to produce time-varying thermal gradients along the axial and radial directions. Data on the induced peak rate are presented for coils wound using the conventional (end-to-end) wind and the quadrupolar (center-to-end) wind. The quadrupolar-wound coil exhibits substantially lower sensitivity to temperature transients. It is found that the conventional wind can be considered for low-perlormance, low-cost systems operating in moderately adverse environments.

A shearing interferometer is proposed for the characterization of microlenses. The optical configuration of the test system enables the measurement of the wave aberrations, the focal length, and the deviations of the lens surface from an ideal sphere. In addition, a quantitative evaluation method is given that enables the calculation of the wave aberrations (e.g., the phase function) from the shearing interferometer data.

We present results that show lasing on the 3p->3s (J = 0->1) transition in neon-like chromium (Z = 24), iron (Z = 26), and nickel (Z = 28) at 28.5, 25.5, and 23.1 nm, respectively. These results destroy the uniqueness of the lasing observed several years ago in neon-like titanium (Z = 22) at 32.6 nm on the same transition and makes highly unlikely the hypothesis that resonant photopumping is playing a significant role in the titanium laser. The titanium, chromium, iron, and nickel experiments all require a prepulse in order to lase, and our calculations suggest that the prepulse is an exciting new way to create a uniform low-density plasma that allows the proper conditions for gain and laser propagation for low-Zneon-like ions when illuminating a thick slab target. We also present an observation of hyperfine splitting in neon-like niobium at 14.6 nm and offer an explanation as to how the hyperfine effect is reducing the gain of neon-like ions with odd Z.

Two-wavelength interferometry is a well-known technique to enlarge the ambiguity range of conventional interferometric ranging systems. The main problem with this technique is that the light source used must generate the desired wavelengths, which must be adaptable to the actual application. Those wavelengths have to be known precisely and must be stabilized to the desired accuracy. Because of the lack of an inexpensive, compact, and intense light source that provides for the desired wavelengths, two-wavelength ranging systems previously have been without technical importance. We present a new light source for this purpose, which is based on stabilized semiconductor lasers. Our system generates two stabilized wavelengths in the submicrometer range and a synthetic wavelength in the submillimeter range, respectively. In the case of the submillimeter wavelength, both laser wavelengths are locked to the same Fabry-Pérot resonator. This method, previously known in principle, is used for semiconductor lasers for the first time.

Analytical techniques for determining intermodulation distortion in directly modulated semiconductor lasers are examined. Direct expressions for the two- and three-frequency third-order intermodulation distortion-to-carrier ratios are used to check the validity of a well-known 6-dB difference formula. It is found that this formula is not always valid, the discrepancy being a function of laser diode parameters and subcarrier spacing. The carrier-to-intermodulation-noise ratios are computed for a 25-channel subcarrier multiplexed system, with subcarrier spacings of 6 MHz for amplitude modulation and 40 MHz for frequency modulation, and it is found that the central subcarrier is not always the worst affected, although it has the maximum number of interfering intermodulation products. This is in contrast to memoryless nonlinearities where the central subcarrier may be expected to have the worst carrier-to-intermodulation-noise ratio.

We present an experimental procedure for the determination of the physical properties of an arbitrary twisted-nematic liquid crystal cell. No assumptions are made about the physical properties of the cell, because the commercially available devices are generally produced under proprietary conditions. The techniques developed were then used to evaluate the Jones matrix of an Epson liquid crystal television, and reasonable agreement is observed between theory and experiment. Knowledge of the Jones matrix for these devices helps to evaluate their performance as spatial light modulators in optical processing systems, and such applications are discussed. It also provides an effective means for determining the spatial quality of the liquid crystal layer. We find that there is significant variation in the birefringence across this cell, and the influence that this has on the use of the cell in optical processing systems is discussed.

Binary morphological granulometric size distributions were conceived by Matheron as a way of describing image granularity (or texture). Since each normalized size distribution is a probability density, feature vectors of granulometric moments result. Recent application has focused on taking local size distributions around individual pixels so that the latter can be classified by surrounding texture. The extension of the local-classification technique to gray-scale textures is investigated. It does so by using 42 granulometric features, half generated by opening granulometries and a dual half generated by closing granulometries. After training and classification of both dependent and independent data, feature extraction (compression) is accomplished by means of the Karhunen-Loeve transform. Sequential feature selection is also applied. The effect of randomly placed uniform noise is investigated. In particular, the degree to which training in noise increases robustness across noise levels is studied, and feature selection is employed to arrive at a noise-insensitive set of granulometric classifiers.

A novel regularization technique is proposed for the restoration of signals distorted by a stochastic, shift-variant impulse response (blur) function and additive noise. The generic ill-posed inverse problem is formulated as a constrained optimization problem wherein a new cost function, termed stochastic constrained restoration error energy, is minimized. For signals that are quantized in amplitude and sampled in time or space, an artificial neural network is developed and implemented for computational efficiency. By matching the cost function with the energy function of the neural network, the interconnection strengths and bias inputs of the neural network are related to the degraded signal, blur statistics, and constraint parameters. The solution that minimizes the energy function of the neural network is then obtained by the simulated annealing algorithm. Simulation results are also provided to demonstrate the effectiveness of the proposed approach.

A back propagative neural network (NN) was used to select visible spectrum (400 to 700 nm) wavelengths and classify damaged and undamaged peanut kernels. Results showed kernel classifications were best, network errors were minimized, and speed of convergence was greatest when the NN was set up with 20 or more hidden nodes, a momentum of 0.45 or less, and using about 1,000,000 learning events. Reflectance data in the 620 to 700-nm range were most influential in classifying kernels followed by relative reflectance in the 400 to 480-nm range. The learning rate did not affect NN performance, but higher learning rates converged more quickly. The most accurate classification performance occurred when the NN had 40 hidden nodes and a momentum of 0.45. These settings resulted in correct classification of 87.8% of all kernels. When compared to statistical means of classifying kernels using data from specific wavelengths or data from a colorimeter, the NN correctly classified about 5% and 13% more kernels, respectively.

A new computer-controlled phase-shifting apparatus based on polarization techniques is developed. This apparatus changes phase only by rotating a polarizer using a precise step motor and a specially designed decelerator. The precision of this method can be higher than other methods because of the accurate control of the rotating angle. Four applications of this technique to optical interlerometry and 3-D shape measurements are presented.

Software for star field identification and star pointing and tracking is described. The software will be implemented in the guiding system of UVSTAR, a spectrograph/telescope system for UV astronomy and planetary physics that will operate as a Hitchhiker payload on the Shuttle. The software work with the wide-field CCD camera and an on-board stellar catalog. It is capable of (1) providing high accuracy (better than 2 arcsec) attitude determination from coarse (± 3 deg) initial knowledge of the pointing direction and (2) pointing toward the target. It is capable of tracking at the same high accuracy with a processing time of less than a few hundredths of a second. Simulation of observations and various types of tests are also discussed.

The preliminary design of a noninvasive glucose sensor developed in this investigation was based on the polarization rotation of light produced by optically active molecules. The polarimeter developed for this investigation was unique when compared to previous investigations in that it utilized a single Pockels cell to both modulate the signal and provide feedback within the system. The intended application of this polarimeter is to measure glucose concentrations within the aqueous humor of the eye. The purpose of this investigation was to elucidate whether the theory of superposition and multispectral analysis can be applied to the measurement of glucose in the presence of ascorbic acid and albumin, the most significant rotatory confounders found in the aqueous humor. The results of this investigation indicate that superposition of rotation at different wavelengths due to the above optically active molecules was valid for the in vitro experiments conducted. Utilizing two wavelengths of light, the concentration of hyperglycemic levels of glucose were derived in the presence of physiological concentrations of the optically active confounders ascorbic acid and albumin. It was found, except for one outlier, that the model predicted glucose concentrations to within 23%.

A real-time 2-D surface profile measurement system is described. In this system, a laser diode and a 2-D charge-coupled device image sensor are used as a light source and a photodetector, respectively. The phase is detected from the sinusoidal phase-modulating interference signal using the high-speed electrical circuit. The time required for phase detection is 20 ms for 50 x 40 measuring points. Because the phases can be obtained for even and odd fields of the image sensor, the original spatial resolution of the image sensor is not reduced in this system. Repeatability of the measurement is ~14 nm, rms.

Two optical methods are proposed for shape measurement and defect detection of curved surfaces in the form of a complete 360-deg profile of the object. The first one is the standard structured light approach. Display of the resulting data is the emphasis of this section. The second approach uses modulated structured light with a scanning digital camera for faster and simpler data acquisition. Quantitative processing is done off-line while real-time moiré produces enhanced display of the defects for qualitative analysis.

A laser beam scanner, used as an angle measuring device in a particular navigation system for mobile robots, has been developed. It measures heading angles to beacons made of vertical stripes of retroreflective tape. Expressions giving the received power and energy in the pulse, which is generated when a beacon is traversed by the laser beam, are given. Measurements support the derived expressions. The shape and amplitude of the pulse are functions of the range R to the beacon, but at long range the pulse shape and width become independent of range while the dependence of the received amplitude on range becomes R^-3. At long range the pulse shape is determined by the Gaussian irradiance distribution in the laser beam and the pulse width is governed by the laser beam divergence and the scanning speed. Design rules for the optimum field of view of the receiving optics and for an electrical filter, which maximizes the signal-to-noise ratio, are proposed. An expression giving a conservative estimate of the signal-to-noise ratio is derived.

New methods of calculating the optical schemes of flat-field spectrographs with holographic diffraction gratings, high-numeral- aperture spectrographs with a new type of holographic diffraction grating, and spectrographs with wide spectral regions are described. Particular optical schemes for spectrographs and their aberration characteristics are considered.

A new approach to solve the radiative transport equation for time-resolved spectroscopy is presented. A new phase function that shows much better agreement with Mie theory than Henyey-Greenstein's phase function is introduced. Initial laser beams are properly modeled. For every small time increment, precise and analytical solutions are found to satisfy the radiative transport equation for the uniform field, wide beam, and narrow beam. Computer simulations give promising results. Different conditions of initial beams, media, and medium abnormalities are discussed. A strategy for using the semianalytical solutions to reconstruct the regional distribution of the scattering attenuation coefficient and future work are described.

Modern methods of surface examination show that even high-quality surfaces, fit for their intended purpose, are subject to surface imperfections. Thus it is necessary to agree on imperfection thresholds acceptable for particular applications. After a brief description of four national standards, a table of imperfection threshold values is presented as a quality guideline for different applications. This is based on mean values obtained from an international survey conducted by the author under the auspices of the International Commission for Optics.

Preliminary x-ray diffraction tomographic experiments utilizing synchrotron radiation have been performed at the Australian National Beamline Facility (BL20B) of the Photon Factory, National Laboratory for High Energy Physics in Japan. The tomographic instrument arrangement consisted of a double silicon crystal monochromator, motor-driven beam-defining collimation slits, and microcomputer-controlled specimen movement stages and was designed to simultaneously record tomographic data from multiple transmission and scatter radiation detectors. Image plates were used to record the scattering properties of specimen constituents, which facilitated registration of the scatter detectors. The design of the instrument is described and some preliminary results are presented.

This PDF contains the communication "Desensitized holographic measurement of longitudinal displacements."

This PDF contains the communication on "Object movement characterization from low-light-level images."

This PDF file contains the editorial “Book Rvw: Photonic Aspects of Modern Radar," edited by Henry Zmuda and Edward N. Toughlian for OE Vol. 33 Issue 08

This PDF file contains the editorial “Book Rvw: Semiconductor Optoelectronic Devices," by Pallab Bhattacharya for OE Vol. 33 Issue 08