Just a few days before writing this editorial I spoke to a group at the University of Rochester as they began the process of planning for the sesquicentennial of our institution. It is certainly interesting to think about the changes in the university over the 150 years since its founding in 1850.

We describe the visibility function in polarized light for a cophased N-aperture synthesis array made of ground-based optical telescopes. Instrumental polarization induces attenuations depending on both the differential field rotations and the phase delays from incoming beams, whereas the combination of N beams leads to a power transmission divided by N in the modulation transfer function. For asymmetrical arrays, we optimize two compensators for field rotation: three-reflection optics in rotation around the optical axis of each interferometric arm and a pyramidal beam-combiner similar to a very large Cassegrain telescope. These correctors are equivalent in terms of visibility losses so that trade-offs must be found between mechanical requirements and SNR. Finally, the separation of the two polarizations before recording the fringes is very attractive for future interferometric projects since it greatly reduces the data bias and also provides visibilities in polarized light and therefore new constraints on polarization mechanisms in stellar atmospheres

A detailed description of the design of a plastic, aspheric Fresnel lens on a spherical surface is provided. The design technique is based on calculating solutions to Snell’s law along the lens surface. These lenses were intended for the wavelength range of 8 to 12?m. However, the method easily applies to lenses designed for other wavelengths. The procedure used to manufacture the lenses is to construct a diamond-turned master surface, followed by injection molding with highdensity polyethylene.

We investigate the robustness of an image encryption technique that uses random phase encoding in both the input plane and the Fourier plane when the encrypted image has been distorted. The distortions include different types of noise, loss of encrypted data, and the binarization of the encrypted image. It is shown that decryption transforms the noise added to the encrypted image to a wide-sense stationary additive white noise. Consequently, regardless of the type of the noise added to the encrypted image, the quality of the recovered image can be improved by processing techniques designed for filtering out additive white noise. The double-phase encryption technique distributes the input image over the entire output plane, which provides robustness to the distortions due to loss of encrypted data. Regarding the binarization, it enables easy implementation and data compression while recovering images of good quality may be possible.

An approximate analytical theory is developed to describe the effects of temperature on the birefringence in a coated stress-induced birefringent optical fiber. Because of the mismatch in the thermal expansion coefficients of the cladding and the stress-applying sections in the fiber, the birefringence in the fiber responds directly to a change of temperature. Additional changes in the birefringence can be produced indirectly by the temperature-induced radial stress and axial strain in the glass fiber through the fiber coating. Depending on the coating material and thickness as well as the thermoelastic properties of the fiber glasses, the indirect effect can reinforce or cancel the direct effect. It is possible to design a fiber with a birefringence that is insensitive to temperature variation over a range of temperature. Expressions suitable for fiber design are presented. Both plastic and metal coating materials are considered. Design examples for boron-doped fibers are given.

A compact, portable fiber optic biosensor is developed that enables monitoring of up to four fiber optic probes simultaneously. The sensor employs a novel optical fiber bundle jumper for exciting and collecting fluorescence emission from the evanescent wave fiber optic probes. A single fiber in the center of the bundle couples laser excitation into the sensor probe, while the surrounding fibers collect the returning fluorescent emission light. This design requires no beamsplitter, enabling the detection optics and control circuitry to be reduced to a 436 in. circuit card. Four of these cards are integrated into a single portable system. Results from detection assays for hazardous biological agents and an environmental pollutant are shown.

A method based on the Monte Carlo procedure is suggested to simulate the reconstruction of non-Fourier-type computer-generated holograms (CGHs). The cases of amplitude holograms (CGAHs) and phase holograms (CGPHs), or ‘‘kinoform lenses,’’ are investigated. A method to model the finite pixel size of the hologram is suggested. An importance sampling method is proposed to simulate the reconstruction of CGAHs

A hybrid adaptive block truncation coding (HABTC) method is presented to improve block truncation coding (BTC)-related compression methods for gray-level images. The basic idea behind the method is to use various coding schemes to take advantage of local image characteristics. A simple linear interpolation coding scheme and a very basic predictive coding scheme are used to improve the compression ratio of the homogeneous area of the image. Moreover, a four-level BTC, whose thresholds are obtained using a radius-weighted mean (RWM), is applied to encode the inhomogeneous area. The bits per pixel/peak SNR (bpp/PSNR) values listed in many other BTC-related papers are cited and compared with ours. It is found that reasonable compression ratio is obtained by the proposed HABTC method and the visual quality of the decoded images is also acceptable.

Linear prediction schemes, such as that of the Joint Photographic Experts Group (JPEG), are simple and normally produces a residual sequence with lower zero-order entropy. Occasionally the entropy of the prediction error becomes greater than that of the original image. Such situations frequently occur when the image data have discrete gray levels located within certain intervals. To alleviate this problem, various authors have suggested different preprocessing methods. However, the techniques reported require two passes. We extend the definition of Lehmer-type inversions (Lehmer 1960 and 1964) from permutations to multiset permutations and present a one-pass algorithm based on inversions of a multiset permutation. We obtain comparable results when we apply JPEG and even better results when we apply some other linear prediction schemes on a preprocessed image, which is treated as multiset permutation.

The field of image restoration lacks a promising comparison vehicle for judging the effectiveness of competing algorithms. By far the most widely adopted quantitative measurement of image restoration performance is by means of the SNR improvement. We address the issues of performance assessment of image restoration and propose a unified framework for the performance measure. The SNR improvement, which is within the proposed framework, is shown to be an inappropriate performance measure for image restoration. By introducing a metric for pixel fidelity improvement and incorporating the main properties of the human visual system into the measurement, we devise a performance measure of better quality, particularly of higher precision.

Separating halftones from text is an important step in document analysis. We present an algorithm that accurately extracts halftones from other information in printed documents. We treat halftone extraction as a texture-segmentation problem. We show that commonly used halftones, consisting of a pattern of dots, can be viewed as a texture. This texture exhibits a distinct spectral component that can be detected using a properly tuned Gabor filter. The Gabor filter essentially transforms halftones into high-contrast regions that can be easily segmented by thresholding. We propose a filter design procedure and provide experimental results.

We propose a new texture measurement, the full custom texture measurement (FCTM) calculated from the cooccurrence matrix. The new measurement provides a general framework for the analysis of images from a textural viewpoint. It is shown that different textural features can be designed through the FCTM. In particular, it is demonstrated that the conventional cooccurrence-matrix-based texture features are special cases of the FCTM. The FCTM is well suited for analyzing images under multiresolution signal decomposition, due to its flexibility in dealing with different signal structures in different decomposition levels and signal bands. Combined with multiresolution signal processing, we applied the FCTM to motion estimation in low-bit-rate video coding. Experimental results show that coding methods incorporating the FCTM provide reconstruction quality superior to a well-known codec

A shot-noise-limited image profiling technique is developed whereby the images of special classes of objects that fall substantially below the conventionally defined diffraction limit can be characterized with respect to their shape, size, orientation, and reflectance. This is accomplished via the point-by-point subtraction of a point-source reference profile from the unknown object profile, the resulting difference profile providing a ‘‘fingerprint’’ of the unknown object. Computer simulations of this process have been validated by experiments conducted with 8-channel and 64-channel profiling instruments. The latter instrument performs hundreds of profile scans per second: autocentering, downloading, and integrating the scans so as to provide shot-noise-limited profiles in near-real time. Experiments conducted to date have demonstrated the characterization of objects subtending angles as small as 0.07 ?/D, where ? is the dominant wavelength of radiation and D is the diametric aperture of the optical instrument used to achieve that resolution. It is predicted that an instrument similar to the 64-channel system, when used in conjunction with a 1-m telescope in an exoatmospheric environment, will make it possible to characterize objects that are significantly less than a meter in size from distances in excess of 10,000 km. Meanwhile, its application to microscopy likely will make possible the in vivo study of viruses.

Symmetry detection is important in the area of computer vision. A simple and fast algorithm for the recovery of rotational symmetry parameters is developed. The fold number of a rotationally symmetrical shape is obtained from the gradient orientation histogram of the input gray-level image using the Fourier method, based on the relationship between the periodicity of the orientation histogram and the fold number of the symmetrical shape. It takes only 0.06 s CPU time for a 256 3256 gray image on a Sun SPARC10. Both simulated and real images are tested and the results are very convincing.

We propose a dynamic wavelength router using a multimode interference coupler and Bragg gratings implementing multiport wavelength switching in a single device together with a new wavelength dilation method using this device. We show a design of the new dynamic wavelength router and device performance using eigenmode decomposition. The flat passband and low crosstalk characteristics are attained.

Theoretical and experimental studies are presented on the two commonly used laser diode astigmatism measurement methods: the moving-diode method and the moving-profiler method. Both methods use lens(es) to focus the laser beam and a camera (or beam profiler) to locate the focal point of the focused beam. It is theoretically shown that the moving-diode method is valid when the distance between the diode and the lens is much larger than the lens focal length and the camera is positioned at a corresponding distance to the lens, and that virtually no calculation is required in a measurement. It is theoretically and experimentally shown that the moving-profiler method is valid when the measured data are elaborately processed using Gaussian optics and that the previous measurement with the measured data being processed by geometric optics was wrong.

Advanced solar cells and other optical detection devices incorporate surface texturing to reduce optical reflection and enhance absorption. Using electrochemical etching techniques, porous silicon surfaces are fabricated. Thin (pore depths less than 1 ?m) and thick (pore depths greater than 5 mm) porous silicon surfaces are optically characterized in terms of their ability to reduce optical reflectance. Three regions of the optical spectrum were investigated: visible (500 to 900 nm), near-IR (1.25 to 2.5 ?m), and mid-IR (2.5 to 12.5 ?m). A highly polished, single-crystal silicon wafer was used as a reference surface. It was determined that thick porous silicon manifested superior results compared to the thin porous silicon, demonstrating a 91% total reflectance reduction in the visible region, a 7% reduction in the near-IR range, and a 53% reduction over the mid-IR wavelengths.

Spherical microlenses are fabricated in a modified melting technology. Resist cylinders are patterned by photolithography and subsequently dissolved in a controlled solvent atmosphere. This technique enables the fabrication of spherical resist microlenses of selectable rim angles in the range from 1 to 30 deg. Photoresist microlenses with a focal length of 20 mm, a diameter of 1 mm and a good sphericity are realized. The photoresist lenses are transferred into the silicon substrate through reactive ion etching. Within the inner 80% of the lens diameter, the deviation of the silicon lenses from a sphere amounts to less than ?/20 at ?51.55?m. The resist and silicon lenses are characterized by mechanical and interferometric methods. This technology is compared with the well established melting technique.

It is well known that the foci of a periodic array of microlenses are reproduced and multiplied in the fractional Talbot planes. But the intensity between the multiplied foci varies in general in one period, especially if the light in the spacing between the lenses is not absorbed but transmitted. Additionally, in the case of microlenses with a high numerical aperture the parabolic approximation or Fresnel diffraction, which is normally used to explain the Talbot effect, is no longer valid. A theoretical explanation and numerical simulations are given together with experimental results.

The surface normal of a range image of a face can be decomposed into three components. The combinations of these three weighted components produce 2-D intensity images with different illuminations. A phase-only vector filter is designed based on these normal components. With such a vector filter, the face recognition can be performed between range face and range face, or between range face and intensity face. This kind of recognition is less sensitive to the changes of illumination of the input face.

A new approach for scaling, rotation, and translation invariant object recognition is proposed. The geometric discrepancy between the test pattern and the related reference pattern can be reduced by applying affine transform to the test pattern with the parameters estimated from the affine relation between the control points of both parties. The automatically paired control points are the centroids of patterns’ desired regions with specific gray level distributions. By means of the analysis of intrinsic invariance properties, a small number of reference templates are required to deal with the residual geometric variation of the transformed test pattern. Consequently, a simple similarity measure can be employed directly without any scale and rotation invariant feature extraction.

To locate and recognize ground-based targets in forwardlooking IR (FLIR) images, 3-D faceted models with associated pose parameters are formulated to accommodate the variability found in FLIR imagery. Taking a Bayesian approach, scenes are simulated from the emissive characteristics of the CAD models and compared with the collected data by a likelihood function based on sensor statistics. This likelihood is combined with a prior distribution defined over the set of possible scenes to form a posterior distribution. To accommodate scenes with variable numbers of targets, the posterior distribution is defined over parameter vectors of varying dimension. An inference algorithm based on Metropolis-Hastings jump-diffusion processes empirically samples from the posterior distribution, generating configurations of templates and transformations that match the collected sensor data with high probability. The jumps accommodate the addition and deletion of targets and the estimation of target identities; diffusions refine the hypotheses by drifting along the gradient of the posterior distribution with respect to the orientation and position parameters. Previous results on jumps strategies analogous to the Metropolis acceptance/rejection algorithm, with proposals drawn from the prior and accepted based on the likelihood, are extended to encompass general Metropolis-Hastings proposal densities. In particular, the algorithm proposes moves by drawing from the posterior distribution over computationally tractible subsets of the parameter space. The algorithm is illustrated by an implementation on a Silicon Graphics Onyx/Reality Engine.

A new observer design method that allows for estimating the angular rates along a vehicle’s three principal axes is described. The observer uses measurements from a single two-axis angular rate sensor (gyro) and determines the rates for the third axis using a nonlinear observer. Unlike conventional approaches where the equations governing vehicle motion (Euler’s equations) are linearized and then an observer is constructed based on the linear model, this method does not require linearization of the system. Instead, a pseudo-linear representation is used. The pseudo-linear model is obtained by systematically decomposing a nonlinear system into linear and nonlinear terms. The nonlinear components are then redefined as an auxiliary set of state variables and/or inputs. This leads to an augmented linear system representation that is mathematically equivalent to the original nonlinear system. This method enables standard linear observer design techniques to be applied and develops observers that are capable of estimating the thirdaxis angular rates using measurements corresponding to the other two axes. The effectiveness of this approach is illustrated with an example. The case studied is the complete attitude rate determination and control of a spinning spacecraft. Computer simulation results show that the new approach provides excellent three-axis attitude control, yet requires angular rate sensors for only two axes.

We propose a 3-D target attitude estimation method based on linear optimal filtering and prediction algorithms. Through the use of correlation filters, the estimations of the 3-D attitude and scale of the target enable us to predict the temporal trajectory of the target and to perform a robust tracking. We propose a strategy to maintain a low number of correlations and thus to reduce the computational burden and the processing time. We demonstrate the efficiency of this approach in the case of optimal trade-off filters and sequences of noisy images.

Due to the time-varying behavior of the Doppler frequency of radar returns, and due to the multiple backscattering behavior of radar targets, the resolution of radar images can be significantly degraded and those images may be blurred. Conventional radar processors use the Fourier transform to retrieve Doppler information. To use the Fourier transform properly, some restrictions must be applied: the scatterers must remain in their range cells and their Doppler frequency shifts should be stationary during the entire imaging time. However, due to a target’s complex motion, the Doppler frequency shifts will be timevarying. Therefore, the Doppler spectrum obtained from the Fourier transform will be smeared, and, the radar image will be blurred. However, the restrictions of the Fourier transform can be lifted if the Doppler information is retrieved with a time-frequency transform that does not require a stationary Doppler spectrum. The image blurring problem caused by time-varying Doppler frequency shifts can be solved without resorting to sophisticated motion-compensation techniques. By replacing the conventional Fourier transform with a time-frequency transform, a 2-D range-Doppler Fourier frame becomes a 3-D time-range-Doppler cube. By sampling in time, a time sequence of 2-D range-Doppler images can be viewed. Individual, time-sampled images from the cube provide superior image resolution. When targets contain cavities or ducttype structures, these structures’ scattering mechanisms appear in radar images as blurred ‘‘clouds’’ extending in range. It is beneficial to incorporate the time-frequency transform into range profiles of the radar image. By so doing ‘‘clouds’’ can be removed and structure resonance frequencies identified.

Speckle interferometry has long proven its usefulness for measuring the deformation and contours of objects with rough surfaces. Nevertheless, the influence of a parameter as important as the lens aperture of the imaging system on the result of the measurement is still not precisely known. Generally, it is stated that the speckles must be resolved by the camera and that therefore the lens aperture number should be large enough (e.g., f /11 or f /16 for typical applications with a standard CCD). It is shown, theoretically as well as experimentally, that it is not necessary to resolve the speckles when making measurements in speckle interferometry. The joint probability distribution of the pixel modulation and the pixel background intensity, which determines the percentage of valid pixels, is investigated for different lens aperture numbers, i.e., for different numbers of speckles per pixel. The comparison between theory and the experimental counterpart enables a number of speckles per pixel to be determined for any given aperture number and pixel size. It appears that the average pixel modulation remains high enough even with a relatively large number of speckles per pixel. The results lead to the conclusion that, especially when the total camera noise is low enough, lens apertures up to f /2 can be used. Thus, measurements are less constrained by limited laser power and decorrelation effects.

A new type of normal incidence scanning reflectometer is designed and constructed. In the system design, instead of using a reference reflective sample or the optical path adjustment methods as in traditional design, we use a fused quartz M-type prism to split the beam of incidence light into two beams in a total internal reflection configuration. The spot sizes, intensities, and spectral responses of these two light beams, therefore, are identical. One reference beam goes directly to the detector. Another sampling beam goes to the sample and is measured by the same detector after beam reflection. A metal disk having three holes is driven precisely by a stepping motor and is used to control the reference and reflection beams as well as the background signals, which are measured in sequence. In terms of the three signals, the absolute reflectivity of the sample at a certain wavelength can be determined immediately using the computer. The system is controlled automatically by the computer with a working wavelength range from 400 to 800 nm. The incidence angle is fixed and equals about 5 deg. The details of the system design, optical configuration, and error reduction are given and discussed. The measured spectral results of the reflectivity for a few testing samples are also given, and are shown to be in good agreement with those measured by other optical methods. The designed system, however, is simpler and can be used in many optical studies.

We describe a new form of prism spectrograph system based on aplanatic principles. The basic system is simple, comprising a prism with two spherical refracting surfaces, both operating near their aplanatic conjugates, and a spherical mirror operating near its center of curvature. This form provides a flat, accessible focal surface suitable for use with modern array detectors. Good image quality can be maintained over large wavelength intervals at fast focal ratios, making this form particularly useful for moderate resolution spectrography. Its simplicity, compactness, and tolerance of misalignment make it attractive for space and cryogenic instruments. We present three examples of operating instruments that have been constructed using this new form.

This paper presents a device that detects light emerging from the combustion inside a series production automotive engine. Simultaneous time and wavelength resolution is achieved by this system and it can be applied in a simple manner to either diesel or spark ignition (SI) engines without any geometrical modification of the combustion chamber. An optical probe is inserted into spark plug or glow plug. A fiber is connected to the probe and leads the light to a spectrograph, which provides spectral analysis in the UV and visible wavelength ranges. An intensified streak camera with time resolution in the microsecond range completes the detection unit. This measuring system enables timeresolved emission spectroscopy applied to the light emitted during the combustion in a series production engine. Time-resolved emission spectra are presented from both a diesel and an SI engine. The time behavior of the internal temperature in a diesel engine combustion chamber and its dependence on engine speed and load are measured with this setup using a multiple two-color method. In an SI engine, the time behavior of the emissions of specific molecules or radicals is detected. Thus, differences in the combustion process are demonstrated to be caused by operation with different fuels.

Second-harmonic generation can be used to probe the microstructure of materials. This nondestructive all-optical method is applied to quantify the orientation of the aluminum nitride microcolumns. Theoretical results show that very small tilt angles of the columns are easily detectable. The sensitivity of this technique is confirmed by experimental results, which are compared with piezoelectric measurements

We experimentally demonstrate that part of the absorptance of coated multicomponent glass substrates results from a photoinduced absorptance of the substrate during the evaporation process. This increase in the glass substrate absorptance is due to a solarization process by UV radiation, which is produced in the coating plant when electrons emitted by the electron gun interact with the material to be evaporated. Thus, we can experimentally show the dependence of the multicomponent glass substrate absorptance on the evaporation time. An original method of front and back illumination of samples is presented that enables the separation of each part of the in-depth absorptance using photothermal measurements: bulk and interface absorption of the thin film and substrate photoinduced absorption. This new method overcomes the difficulties presented by other measurement techniques and caused by the dependence of substrate and interface absorptances on the evaporation time. Absorption losses in different single-layer films are balanced.

The final design and testing of a filter for the Australian Navy’s Laser Airborne Depth Sounder is reported. This filter is a six-stage, actively tuned, Lyot birefringent filter with approximately 10 times better signal-to-noise performance than the narrow-band filter currently in use. It is expected that this filter will improve the available flying time by up to 6 h/day.

Electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD) is used to deposit thin films of SiNx of different composition from mixtures of N2 and 30% SiH4 in Ar onto different substrates. Measured values of the complex refractive index over the wavelength range of interest are used in the design and computercontrolled fabrication of one- and two-band rugate optical interference filters. The excursion of the continuously varying refractive index is chosen to be between 0.8 and 1.2, and window functions and matching layers at both sides are employed for sidelobe suppression. Measured reflection patterns of filters agreed well with simulated results. Filters designed for a center wavelength of 1000 nm and a total thickness of 2.1 ?m, have a reflectance of 97% in the stopband and a bandwidth of typically 240 nm. The two-band filter is designed for stopbands at 1000 and 770 nm with reflectance of 98 and 96% and bandwidths of 150 and 120 nm, respectively. The total thickness of this filter is 3.33 ?m. Filters are successfully deposited on optical fiber ends using one of the fibers for in situ monitoring of the deposition process.

Micropatterned interference filters are developed by dry etching of dielectric multilayer stacks. The application of reactive-ion etching (RIE) techniques combined with the use of an etchstop layer are shown to be quite effective in producing two-stage micropatterns with defined spectral properties. By using a MgF2 underlayer the etching of TiO2 and SiO2 layers is stopped exactly, which provides the possibility to develop large area patterns (>1×1 cm2) with feature sizes as small as 10 mm. The distortion of edge features is shown to be better than 1 ?m. A filter array was developed providing high-reflection and antireflection coatings within a period of 20 ?m.

The transillumination window in the tissue spectrum, which extends from about 600 to about 1200 nm, is very attractive in diagnosis and therapy because the penetration of light into tissues ranges from several micrometers to several millimeters. Problems with the evaluation of red and near-IR light-tissue interaction are of great importance in the development of noninvasive blood oximetry. It is shown that it is possible to use a simplified one-dimensional (1-D) representation of such an interaction with a reliability acceptable in practice. The state of the art, taken into account here as the background, refers to the reported optical parameters of tissues when exposed to light of wavelengths included in the optical window considered. Against that background, using the arterial blood oxygen saturation as a measurement quantity, a reasonably complicated model of noninvasive processes occurring in a living object as a pulsatile inhomogeneous optical medium is presented. During the calculations and experiments, a novel use of the known transmission variant of the pulse oximetry concept is considered. At two measuring wavelengths (i.e., 660 and 940 nm), the biophysical and optical properties of living tissues are involved in relationships that include the quantities to be directly measured with known accuracy. Finally, the results of calculations referring to the transilluminated representative object (i.e., a theoretical fingertip) are compared to the appropriate results obtained during a series of measurements performed on real human subjects using the designed measuring system.

The fabrication and characterization of UV-light-imprinted solgel silica glass waveguides on glass and silicon substrates are described. Waveguide fabrication parameters are evaluated. Appropriate combinations of UV light exposure time, sol-gel film thickness, and postbake time produce waveguides suitable for use at a 1.55-?m wavelength. Propagation losses in these waveguides are less than 0.3 dB/cm.

We present a class of discrete-time orthonormal wavelets that are optimized with respect to time duration. The global optimization is achieved via an adaptive simulated annealing (ASA) approach, and the objective function is the average time duration over all scales of the wavelet as defined by the levels of the corresponding binary, treestructured, filter bank structure. We present and discuss the algorithm for generating these optimum wavelets; present the defining filter coefficients {g(n)} for filter lengths of N= 8, 10, 12, 14, 16, 18, 24, and 32; and provide comparisons with Daubechies’ discrete wavelets and other discrete and discrete-time wavelets optimized to other measures based on duration and bandwidth.

A general analysis for the first-order design of a three-lens afocal zoom system with one lens fixed is presented. The reasonable solution areas in the focal length diagrams with positive or negative magnification are derived and shown graphically. The relation between the two separations of the three lenses in zooming is found to be a hyperbola. According to the different locations of hyperbola centers, four cases are analyzed. From the four hyperbolic graphs, we get five different types of zoom systems. For each zoom type, we find the maximum range of magnification and the position where the maximum or minimum system length occurs during zooming. The zoom loci for the first or second lens fixed are also discussed.

CCDs perform two main functions: detecting light by generating free electrons in the pixels, and transferring the photogenerated charge across the device to an output amplifier. The charge transfer process is not always ideal, and this can result in errors when making analytical measurements of point images that only cover a few pixels [e.g., in astronomy and inductively coupled plasma (ICP) spectroscopy].1,2

This PDF contains the communications section including: "Second harmonic generation in single-crystal thin films of 2-(N-prolinol)-5-nitropyridine (PNP)"

This PDF contains the communication section including "Dimensional analysis of the turbulence in a semiconductor laser"

When it was first published in 1983, Optical Holography was written as a selfcontained and complete scientific treatment of holography, with special attention paid to recent developments in the field. Since that time, however, the field of holography has changed dramatically.

This PDF file contains the editorial “Book Rvw: Photonics Rules of Thumb," by John Lester Miller and Ed Friedman for OE Vol. 36 Issue 04