# Showing papers in "Applied Optics in 1986"

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TL;DR: The Handbook of Stochastic Methods covers systematically and in simple language the foundations of Markov systems, stochastic differential equations, Fokker-Planck equations, approximation methods, chemical master equations, and quatum-mechanical Markov processes.

Abstract: The Handbook of Stochastic Methods covers systematically and in simple language the foundations of Markov systems, stochastic differential equations, Fokker-Planck equations, approximation methods, chemical master equations, and quatum-mechanical Markov processes. Strong emphasis is placed on systematic approximation methods for solving problems. Stochastic adiabatic elimination is newly formulated. The book contains the \"folklore\" of stochastic methods in systematic form and is suitable for use as a reference work.

2,383 citations

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TL;DR: A refinement of the Fourier transform fringe-pattern analysis technique which uses a 2-D Fouriertransform permits better separation of the desired information components from unwanted components than a 1-D transform.

Abstract: A refinement of the Fourier transform fringe-pattern analysis technique which uses a 2-D Fourier transform is described. The 2-D transform permits better separation of the desired information components from unwanted components than a 1-D transform. The accuracy of the technique when applied to real data recorded by a system with a nonlinear response function is investigated. This leads to simple techniques for optimizing an interferogram for analysis by these Fourier transform methods and to an estimate of the error in the retrieved fringe shifts. This estimate is tested on simulated data and found to be reliable.

363 citations

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TL;DR: Two design procedures are presented for monomode solid-state laser resonators with large mode volume and low sensitivity both to focal length fluctuations and to misalignment.

Abstract: Resonators containing a focusing rod are thoroughly analyzed. It is shown that, as a function of the dioptric power of the rod, two stability zones of the same width exist and that the mode volume in the rod always presents a stationary point. At this point, the output power is insensitive to the focal length fluctuations, and the mode volume inside the rod is inversely proportional to the range of the input power for which the resonator is stable. The two zones are markedly different with respect to misalignment sensitivity, which is, in general, much greater in one zone than in the other. Two design procedures are presented for monomode solid-state laser resonators with large mode volume and low sensitivity both to focal length fluctuations and to misalignment.

278 citations

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TL;DR: A theoretical modeling is proposed to predict the efficiency factors for attenuation, total scattering, and backscattering for spherical and homogeneous phytoplanktonic cells in suspension to evaluate the reliability of the model for algal cells of various indices and morphologies.

Abstract: A theoretical modeling is proposed to predict the efficiency factors for attenuation, total scattering, and backscattering for spherical and homogeneous phytoplanktonic cells in suspension. The input parameters of this modeling are the actual size distribution, the spectral values of absorption by the living cells, and an adjustable value of the real part of the refractive index. The variations in these parameters lead to very diverse spectral behavior of the efficiency factors. Theoretical predictions are compared to experimental results for some species to evaluate the reliability of the model for algal cells of various indices and morphologies.

274 citations

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TL;DR: Image shifting provides a method of determining the direction of displacement, and hence the velocity, for all types of pulsed laser velocimeter, and it is capable of high performance.

Abstract: Image shifting provides a method of determining the direction of displacement, and hence the velocity, for all types of pulsed laser velocimeter. It is independent of the scattering properties of the particles and/or the intensity of the illumination of the first image with respect to the second image, and it is capable of high performance. With rotating mirror systems, image shifting can be used to offset negative velocities up to 10 m/s. With electrooptic systems, it is estimated that image shifting can be used at velocities up to 500 m/s.

265 citations

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TL;DR: It is shown that for some computational problems, the programming complexity may be so great as to limit the utility of neural networks, while for others the investment of computation in programming the network is justified.

Abstract: Methods for using neural networks for computation are considered. The success of
such networks in finding good solutions to complex problems is found to be
dependent on the number representation schemes used. Redundant schemes are found
to offer advantages in terms of convergence. Neural networks are applied to the
combinatorial optimization problem known as the Hitchcock problem and signal
processing problems, such as matrix inversion and Fourier transformation. The
concept of programming complexity is introduced. It is shown that for some
computational problems, the programming complexity may be so great as to limit
the utility of neural networks, while for others the investment of computation
in programming the network is justified. Simulations of neural networks using a
digital computer are presented.

232 citations

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TL;DR: A laser Doppler velocimeter (LDV) using a semiconductor laser diode (LD) with its self-mixing effect has been developed and is compact enough for many applications.

Abstract: A laser Doppler velocimeter (LDV) using a semiconductor laser diode (LD) with its self-mixing effect has been developed. A Doppler signal, caused by mixing a returned wave with an originally existing wave inside the LD, is detected with a photodetector in the LD package; it is also picked up from the variation of the LD driving voltage. When the returned light is weak enough, it confirms that there is no change in the single-mode oscillation and its spectral width of the LD. A LDV of this type is compact enough for many applications.

229 citations

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Bell Labs

^{1}TL;DR: Examples demonstrate how symbolic substitution logic can be used to implement Boolean logic, binary arithmetic, cellular logic, and Turing machines.

Abstract: Symbolic substitution logic is based on optical pattern transformations This space-invariant mechanism is shown to be capable of supporting space-variant operations An optical implementation is proposed It is based on splitting an image, shifting the split images, superimposing the results, regenerating the superimposed image with an optical logic array, splitting the regenerated image, shifting the resulting images, and superimposing the shifted images Experimental results are presented Examples demonstrate how symbolic substitution logic can be used to implement Boolean logic, binary arithmetic, cellular logic, and Turing machines

225 citations

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Academia Sinica

^{1}TL;DR: Geometrical- and physical-optics analyses of the lens array are reported and compared with the experimental results to show that the uniformity of the illumination of a target can evidently be improved without being affected by the near-field distribution of laser beams.

Abstract: Inserting an array of nearly 100 similar lenses into a common focal system, the uniformity of the illumination of a target can evidently be improved without being affected by the near-field distribution of laser beams. We report here geometrical- and physical-optics analyses of the lens array and compare them with the experimental results.

221 citations

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TL;DR: Sub-Nyquist interferometry (SNI), an extension of PSI, is described and demonstrated to overcome the inability to measure surfaces with large aspheric departures, and it preserves the measurement precision that is inherent to PSI.

Abstract: A technique is described for extending the measurement range of interferometry past the Nyquist limit of the sampling frequency of the interferogram. The absolute phase values measured by an interferometer are reconstructed by applying constraints based upon a priori knowledge of the absolute phase values. The constraints include the knowledge that one or more derivatives of the spatial distribution of phase values is a continuous function, and the knowledge of step heights to within λ/2.

214 citations

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TL;DR: Interferometre a modulation de phase sinusoidale dans lequel une onde de reference est facilement modulee en phase avec un miroir vibrant.

Abstract: Interferometre a modulation de phase sinusoidale dans lequel une onde de reference est facilement modulee en phase avec un miroir vibrant

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TL;DR: This paper proposes a method for measuring distance larger than the wavelength of light with an interferometer using a laser diode, which is a kind of multiwavelength interferometry using a single light source.

Abstract: This paper proposes a method for measuring distance larger than the wavelength of light with an interferometer using a laser diode. This method uses the fact that the wavelength of the emitted light of a laser diode varies in proportion to the diode’s injection current. The phase difference between the two interfering beams varies due to the sinusoidal variation of wavelength. The variation of the phase difference is detected by the optical heterodyne method. The magnitude of the variation is proportional to the measuring distance and the light wavelength shift. If the wavelength shift is known, a distance larger than the wavelength can be obtained from measurement of the phase variation. This method is a kind of multiwavelength interferometry using a single light source. We have done some fundamental experiments with this method and have confirmed its applicability to practical applications.

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TL;DR: Fournier theory deconvolution phase recovery reconstruction from projections Specke imaging and interferometry image processing system design program categories technical practicalities as mentioned in this paper, and Fournier Theory of Deconvolution Phase Recovery from projections

Abstract: Setting the scene Fournier theory deconvolution phase recovery reconstruction from projections Specke imaging and interferometry image processing system design program categories technical practicalities

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TL;DR: In this paper, the photon correlation and other vital performance characteristics of silicon avalanche photodiodes operated in photon counting or the Geiger mode were examined, and their suitability as detectors for photon correlation spectroscopy and laser velocimetry measurements was assessed.

Abstract: We examine the photon correlation and other vital performance characteristics of silicon avalanche photodiodes operated in photon counting or the Geiger mode, and assess their suitability as detectors for photon correlation spectroscopy and laser velocimetry measurements.

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TL;DR: A quarterwave-thick narrow-bandwidth antireflective coating for fused silica optical components and KDP crystals has been developed and it is applied by dip or spin from a solution at room temperature and requires no further treatment.

Abstract: A quarterwave-thick narrow-bandwidth antireflective coating for fused silica optical components and KDP crystals has been developed. The coating consists of porous silica prepared from a silica sol in ethanol. It is applied by dip or spin from a solution at room temperature and requires no further treatment. The laser damage threshold levels are about equal to the surface damage thresholds of the uncoated substrates.

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TL;DR: Using rigorous coupled-wave analysis, high spatial-frequency rectangular-groove surface-relief phase gratings are shown to be capable of exhibiting zero reflectivity, and these corrugated surfaces may act as antireflection coatings in a variety of applications.

Abstract: Using rigorous coupled-wave analysis, high spatial-frequency rectangular-groove surface-relief phase gratings are shown to be capable of exhibiting zero reflectivity. Thus these corrugated surfaces may act as antireflection coatings in a variety of applications. The diffraction characteristics of rectangular-groove surface-relief gratings are presented for several ratios of incident wavelength to grating period as a function of filling factor, groove depth, angle of incidence, and polarization. The conditions for zero reflectivity are identified. Results are compared with single-homogeneous-layer approximate theory results. In the limit of long wavelengths for an electromagnetic wave in a dielectric of refractive index n1 normally incident on a dielectric of index n2, it is determined that for antireflection behavior, the grating groove depth should be λ/4(n1n2)1/2 and the filling factor should be n1/(n1 + n2) or n2/(n1 + n2) for the electric field perpendicular or parallel to the grating vector, respectively. The spectral and angular responses of these gratings are like those of single-homogeneous-layer antireflection coatings. These gratings also exhibit birefringent retardation.

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TL;DR: The measurements of the reflectance of sand wetted with various liquids are in reasonably good agreement with the simple theory and it is suggested that the difference between reflectances of wet and dry surfaces may have implications for remote sensing.

Abstract: It is commonly observed that natural multiple-scattering media such as sand and soils become noticeably darker when wet. The primary reason for this is that changing the medium surrounding the particles from air to water decreases their relative refractive index, hence increases the average degree of forwardness of scattering as determined by the asymmetry parameter (mean cosine of the scattering angle). As a consequence, incident photons have to be scattered more times before reemerging from the medium and are, therefore, exposed to a greater probability of being absorbed. A simple theory incorporating this idea yields results that are in reasonable agreement with the few measurements available in the literature, although there are differences. Our measurements of the reflectance of sand wetted with various liquids are in reasonably good agreement with the simple theory. We suggest that the difference between reflectances of wet and dry surfaces may have implications for remote sensing.

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TL;DR: It is shown how varieties of computer subsystems can be implemented relatively easily by classical optical hardware.

Abstract: Recently, quite strong nonlinear optical configurations such as MQW have been invented. As a consequence, optical logic components with reasonable parameters are now feasible, but that is not enough to justify the development of a digital optical computer. The natural parallelism of optical instruments provides the impetus for developing a highly parallel digital optical computer. The optical technology is not so far behind the electronics technology as one might suspect. We show how varieties of computer subsystems can be implemented relatively easily by classical optical hardware.

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TL;DR: These correlation synthetic discriminant functions (SDFs) are extensions of earlier projection SDFs and provide control of the sidelobe levels and the shape of the output correlation function as well as its peak intensity.

Abstract: Advanced filters are described for distortion-invariant space-invariant object identification and location in clutter using correlators. These correlation synthetic discriminant functions (SDFs) are extensions of earlier projection SDFs. They provide control of the sidelobe levels and the shape of the output correlation function as well as its peak intensity. The theory for synthesis of three such SDFs and a discussion of correlation plane detection criteria for use with these filters are presented.

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TL;DR: The results theoretically demonstrate the feasibility of near-field superresolution microscopy, in which the collimated radiation passed by an aperture is used to circumvent the diffraction limit of conventional optics, and further suggest the feasibilityof near- field superresolution acoustic imaging.

Abstract: The transmission of light through an infinite slit in a thick perfectly conducting screen is investigated. The spatial distribution of the near-field energy flux is determined through the formulation of four coupled integral equations, which are solved numerically. Transmission coefficients calculated by this method are in agreement with those determined by an alternative formulation. The results theoretically demonstrate the feasibility of near-field superresolution microscopy, in which the collimated radiation passed by an aperture is used to circumvent the diffraction limit of conventional optics, and further suggest the feasibility of near-field superresolution acoustic imaging.

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TL;DR: A relevant discontinuity of the coefficient of thermal expan sion has been observed for PMMAs various tacticities and a so-called α peak was observed at ~60°C and was widely discussed by Neki and Geil.

Abstract: J. M. Cariou, J. Dugas, L. Martin, and P. Michel Laboratoire de Physique des Solides, Associé au CNRS, Université Paul Sabatier, 31062 Toulouse CEDEX, France. Received 30 July 1985. 0003-6935/86/030334-03$02.00/0. © 1986 Optical Society of America. For polymers, the thermal volume expansion coefficient is always much higher than the coefficient for inorganic materials. We have recently shown that the variation of the refractive index of polymers vs temperature is essentially due to the variation of density. From the Lorentz-Lorenz relation, the function (n + 2)/(n 1) appears perfectly linear in the various temperature ranges where no phase transition occurs. The slope of the representative curve exactly follows the thermal expansion coefficient α which keeps a constant value in each temperature range. Thus, α may be easily deduced from the refractive-index measure ment at various temperatures. At the same time, the tem peratures where discontinuities of (n + 2)/(n 1 ) or its derivative appear conveniently fit with the transition tem peratures which may be so determined. A correct observation of such behavior is that the tempera ture variations are so slow that the material is continuously kept in thermal equilibrium. Indeed, it is well known that the various molecular processes which induce the transitions are characterized by very large relaxation times. If the material undergoes temperature changes too fast, it remains in a metastable state which is not a true equilibrium state. Waxier et al. have interferometrically measured some optical properties of Plexiglas and Lexan and determined the evolution of dn/dt, with the temperature between -160°C and +60°C. They obtained irregular but continu ous curves which do not evidence, even in a crude way, any systematic change in their behavior which may be related to a phase transition. Nevertheless, in the temperature range studied, at about -30°C PMMA (Plexiglas) undergoes the so-called β transition which is attributed to the beginning of the rotation of lateral chains of methacrylate radicals. A relevant discontinuity of the coefficient of thermal expan sion has been observed for PMMAs various tacticities. In the same way, for polycarbonate, the glass transition at 125°C is out of the temperature range studied by these authors. However a so-called α peak was observed at ~60°C and was widely discussed by Neki and Geil. No noticeable anomaly appears in the Waxier results. We have measured the refractive index of commercial samples of PMMA (Altuglas) and polycarbonate (Lexan) between about -100°C and +150°C. To avoid any stress which could take place by contact with another material, the measurement method chosen was the minimum deviation of a prism. The PMMA prism was drawn from bulk material

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TL;DR: A coherent-optical time-of-flight range-finding technique is proposed which uses a simple inexpensive device and experimental evidence is presented to show the feasibility of measuring distance with subcentimeter resolution over a 1.5-m range.

Abstract: A coherent-optical time-of-flight range-finding technique is proposed which uses a simple inexpensive device. Target range is determined by modulating a laser diode's optical frequency and measuring the change in the phase of the light reflected back into the laser. Target velocity as well as range can be measured using this approach. The device is described, and experimental evidence is presented to show the feasibility of measuring distance with subcentimeter resolution over a 1.5-m range.

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TL;DR: Laboratory measurements of the absorption coefficient and refractive index of solid CO2 are reviewed for all parts of the electromagnetic spectrum from the ultraviolet to the microwave with emphasis on values for temperatures above 77 K.

Abstract: Laboratory measurements of the absorption coefficient and refractive index of solid CO2 are reviewed for all parts of the electromagnetic spectrum from the ultraviolet to the microwave with emphasis on values for temperatures above 77 K The available measurements in some cases require reinterpretation A compilation of the spectral absorption coefficient kabs is made for 52-nm to 160-nm wavelength (with some gaps because of lack of data), and the complex refractive index is then computed by Kramers-Kronig analysis The uncertainty in imaginary refractive index is discussed; it varies greatly with wavelength The real part of the refractive index is close to 14 for all parts of the spectrum except near strong absorption bands and is accurate to ±005 outside those bands No measurements of absorption are available for 180–330-nm, 10–25-μm, and 25-μm–25-mm wavelength, except in the strong narrow absorption lines Remeasurement of kabs is also needed for parts of the IR spectrum between 25 and 25 μm because of experimental error in the available measurements

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TL;DR: A method automatically processing a projected grating to profile a 3-D diffuse object to retrieve phase modulation using a phase detection algorithm similar to that used in communication techniques is proposed.

Abstract: A method automatically processing a projected grating to profile a 3-D diffuse object is proposed. A deformed grating pattern projected on the object is regarded as a phase modulated pattern with a constant spatial carrier frequency. To retrieve phase modulation, acquired data in a microcomputer are sinusoidally fitted using a phase detection algorithm similar to that used in communication techniques. High sensitivity measurements of height distribution can be done using simple optical geometry. Random and systematic errors inherent in the method are discussed in detail.

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TL;DR: It is shown that nonsphericity always increases Qabs for size parameters larger than ∼10, while it decreases g—and correspondingly increases β—in the size range 8 ≤ x ≤ 15, and Concavity almost always enhances the spherical–nonspherical differences.

Abstract: Using the extended boundary condition method, scattering calculations from randomly oriented rotationally symmetric nonspherical particles were made, the size parameters (1-25) and the refractive indicies (1.5 0.02i) of which were chosen to relate to the transfer of solar and IR radiation in an aerosol atmosphere. Comparison of computations for 23 Chebyshev shapes to corresponding size-averaged spherical results revealed that nonsphericity increased absorption for size parameters larger than around 10 and decreased the asymmetry factor, and correspondingly increased the backscattered fraction, in the size ranges 8-15. The scattering efficiency was somewhat larger for nonspherical particles, while the single-scattering albedo tended to be smaller, and concavity was shown to almost always enhance spherical-nonspherical differences.

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TL;DR: A localized approximation to the generalized Lorenz-Mie theory is introduced based on van de Hulst’s localization principle and validation is obtained from numerical comparisons the Rayleigh-Gans theory.

Abstract: Relying on van de Hulst’s localization principle, a localized approximation to the generalized Lorenz-Mie theory is introduced. The validation of this simple approximation is obtained from numerical comparisons the Rayleigh-Gans theory. Other comparisons concerning scattering profiles are carried out first with theoretical data published in the literature and later with experimental measurements. Original results are given for coal particles as an example of the versatility of the method.

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TL;DR: The eigenstate of polarization is introduced to discuss the resonance characteristics resulting from the polarization fluctuation, and the polarization problem in an optical passive ring-resonator gyro (OPRG) is discussed to reveal that this causes gyro drift.

Abstract: Resonance characteristics of an optical fiber ring resonator are derived taking the effect of birefringence into account. We introduce the concept of the eigenstate of polarization to discuss the resonance characteristics resulting from the polarization fluctuation. Using this concept, the polarization problem in an optical passive ring-resonator gyro (OPRG) is discussed to reveal that this causes gyro drift. A way to reduce the drift is to use not polarizers but two polarization controllers. The precision required for polarization control is estimated; it is found difficult to do in practice. We discuss another configuration to solve the polarization problem in an OPRG without polarization controllers.

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TL;DR: This paper presents new results and reviews the latest state of research in all-optical nonlinear logic switches, amplifiers, and memories, and describes optical circuit elements that perform the logic functions of the electronic computer.

Abstract: This paper presents new results and reviews the latest state of research in all-optical nonlinear logic switches, amplifiers, and memories. Optical circuit elements that perform the logic functions of the electronic computer are described. Switching speed on a picosecond time scale, the availability of fast high bandwidth consistent communication, and the application of optical parallelism in free space optical wiring are some advantages of the optical computing elements.