Showing papers in "Journal of Modern Optics in 1979"
TL;DR: In this article, the optical properties of the atmosphere have been investigated and the authors propose a method to estimate the distance from the Earth to the Sun in terms of the distance to the Earth's surface.
Abstract: (1979). Optical Properties of the Atmosphere. Optica Acta: International Journal of Optics: Vol. 26, No. 4, pp. 420-421.
967 citations
TL;DR: In this paper, a linear system, Fourier transform and Optica Acta: International Journal of Optics: Vol. 26, No. 7, pp. 836-836.
Abstract: (1979). Linear Systems, Fourier Transforms and Optics. Optica Acta: International Journal of Optics: Vol. 26, No. 7, pp. 836-836.
332 citations
TL;DR: The Psychology of Visual Illusions: The Seeing is Deceiving: The Psychology of See-Is-Deceive and See-See-See is Deceive as mentioned in this paper is a classic work.
Abstract: (1979). Seeing is Deceiving: The Psychology of Visual Illusions. Optica Acta: International Journal of Optics: Vol. 26, No. 9, pp. 1135-1135.
203 citations
TL;DR: In this article, the principles of interference spectroscopy have been discussed in terms of interferometric Spectroscopy, and the authors propose a method for interferometry in spectroscopic spectra.
Abstract: (1979). The Principles of Interferometric Spectroscopy. Optica Acta: International Journal of Optics: Vol. 26, No. 12, pp. 1449-1449.
176 citations
TL;DR: In this article, computer techniques for image processing in Electron Microscopy Optica Acta: International Journal of Optics: Vol 26, No 4, pp 418-418
Abstract: (1979) Computer Techniques for Image Processing in Electron Microscopy Optica Acta: International Journal of Optics: Vol 26, No 4, pp 418-418
137 citations
129 citations
TL;DR: In this article, a class of non-linear transformations called bilinear (quadratic with memory) is defined; its properties and relevance to optical imaging systems are discussed; and a generalized transfer function is defined for space-invariant systems.
Abstract: Because of the quadratic relation between the optical field and intensity, an inherent non-linearity exists in almost all optical systems. A class of non-linear transformations which we call bilinear (quadratic with memory) is defined; its properties and relevance to optical imaging systems are discussed. For space-invariant systems, a generalized transfer function is defined which characterizes the bilinear system completely. We also examine the approximate linearization of bilinear systems for low-contrast images, and the propagation of noise through such systems. Special emphasis is given to the partially coherent system which is but a special case of this general bilinear system.
95 citations
TL;DR: In this paper, the problem of diffraction by a perfectly conducting lamellar grating is examined numerically and analytically by use of a modal expansion technique and the trajectories of these poles are determined as functions of groove depth, finding that as this parameter increases they move in the complex wavelength plane to a mode threshold, or cut-off wavelength.
Abstract: The problem of diffraction by a perfectly conducting lamellar grating is examined numerically and analytically by use of a modal expansion technique. At various complex wavelengths, with a positive imaginary part, individual mode amplitudes have poles which give rise to resonance effects in the orders at nearby real wavelengths. These are the well-known resonance anomalies. We determine the trajectories of these poles as functions of groove depth, finding that as this parameter increases they move in the complex wavelength plane to a mode threshold, or cut-off wavelength—from a Rayleigh wavelength in the case of S -polarization and from zero wavelength in the case of P -polarization. It is emphasized that the modal expansion technique is particularly valuable in gaining an understanding of the dynamics of diffraction gratings, and that the resonance poles are perhaps the basic dynamical objects determining their behaviour.
91 citations
TL;DR: In this paper, a general expression for the signal-to-noise ratio of a heterodyne lidar system in the presence of atmospheric turbulence is derived which is valid both in the near and far-field of the laser and remoted scattering source.
Abstract: A general expression for the signal-to-noise ratio of a heterodyne lidar system in the presence of atmospheric turbulence is derived which is valid both in the near- and far-field of the laser and remoted scattering source. We consider the situation where a laser transmitter directs an optical beam at some remote scattering region of interest. The backscattered light is collected by a receiving aperture and mixed with a suitable coherent local oscillator reference field. Both coaxial and bistatic lidar systems are considered. In both cases we are able to obtain algebraic expressions for the signal-to-noise ratio which are valid for an arbitrary propagation path through the atmosphere. Numerical results are presented for both a 3.7 and 10.6 micrometer lidar system. Additionally, we obtain the conditions under which atmospheric turbulence will limit severely the performance of heterodyne lidar systems.
80 citations
TL;DR: In this paper, Gradient Index Optics is used to measure the gradients of a point cloud in terms of the gradient of the point cloud and the gradient index of the entire point cloud.
Abstract: (1979). Gradient Index Optics. Optica Acta: International Journal of Optics: Vol. 26, No. 4, pp. 426-427.
68 citations
TL;DR: In a weakly inhomogeneous medium, the Wigner distribution function has a constant value along a geometrical optical light ray as mentioned in this paper, and the transport equation can be formulated in Geometrical Optical terms as follows.
Abstract: Equations have been derived which describe the transport of the Wigner distribution function in homogeneous and inhomogeneous media. In a weakly inhomogeneous medium, the transport equation can be formulated in geometrical optical terms as follows: along a geometrical optical light ray, the Wigner distribution function has a constant value.
TL;DR: In this paper, the detection of optical and infrared radiation was studied in the presence of a single antenna, and the results showed that it is possible to detect optical and IR radiation.
Abstract: (1979). Detection of Optical and Infrared Radiation. Optica Acta: International Journal of Optics: Vol. 26, No. 4, pp. 423-423.
TL;DR: In this article, different techniques for blazing holographic diffraction gratings are compared and the superiority of Fourier blaze, as long as more than two orders propagate, is demonstrated, and the technique for making Fourier blazed gratings is explained in detail.
Abstract: Different techniques for blazing holographic diffraction gratings are compared. Sinusoidal, Sheridon and Fourier blaze are treated. The blaze-wavelength-groove-density combinations possible for each of these different methods are presented as regions in the wavelength-groove-density plane. The superiority of Fourier blaze, as long as more than two orders propagate, is demonstrated. The technique for making Fourier blazed gratings is explained in detail. Theoretical and measured efficiency curves for Fourier blazed gratings are presented and compared to efficiency curves of ruled echelette and sinusoidal gratings.
TL;DR: In this article, it was shown that the initial accommodation response to the out-of-focus, retinal image of a normal, wide-band target must be based on low spatial frequency information.
Abstract: Consideration of modulation transfer functions for the defocused eye and of contrast sensitivity at the retinal level suggests that the initial accommodation response to the out-of-focus, retinal image of a normal, wide-band target must be based on low spatial frequency information. As the response brings the retinal image of the target closer to optimal focus, higher spatial frequency information becomes available, allowing further refinement of the response. These ideas are illustrated by experimental studies of the accommodation responses to grating targets of various spatial frequencies.
TL;DR: In this paper, Coupled-wave analysis is used to calculate the diffraction of two light beams on a volume phase hologram, and the complex amplitudes of the diffracted beams depend strictly on the spatial mismatch of t...
Abstract: Coupled-wave analysis is used to calculate the diffraction of two light beams on a volume phase hologram. The complex amplitudes of the diffracted beams depend strictly on the spatial mismatch of t...
TL;DR: In this article, the Wigner distribution function of an optical signal, which can be considered as the momentary temporal and local spatial spectrum of the signal, is defined, and the transport equations are compared with the eikonal equation in geometrical optics.
Abstract: The Wigner distribution function of an optical signal, which can be considered as the momentary temporal and local spatial spectrum of the signal, is defined. Equations are derived which describe the transport of the Wigner distribution function in a medium, e.g. a plasma, that is weakly inhomogeneous in space and time, and exhibits weak dispersion for the temporal as well as the spatial frequency variable. The transport equations are compared with the eikonal equation in geometrical optics giving, as a geometrical-optical formulation of the transport equations, that along the path of a geometrical-optical light ray the Wigner distribution function has a constant value.
TL;DR: In this paper, a general analysis of signal processing in electronic speckle pattern interferometry is presented, and the effects of limited T.V.-camera resolution is included, and it is shown that the T. V.-monitor brightness is given by essentially the same expression as for full T.
Abstract: A general analysis of signal processing in electronic speckle pattern interferometry is presented. The effects of limited T.V.-camera resolution is included, and it is shown that the T.V.-monitor brightness is given by essentially the same expression as for full T.V.-camera resolution. One term in this expression is the fringe signal, while the others represent noise. The optimal reference-to-object intensity ratio, which maximizes the fringe signal, is determined and the dependence on the size of the aperture is given. The effect of a double slit aperture is compared with the effect of a circular aperture.
TL;DR: In this article, the bending of interference fringes inside a hologram due to a prestress in the photographic emulsion is investigated and the influence of the bending on the diffraction efficiency and the angular sensitivity is explained qualitatively in terms of the Fresnel-Kirchhoff diffraction theory.
Abstract: The bending of interference fringes inside a hologram due to a prestress in the photographic emulsion is investigated. The influence of the bending on the diffraction efficiency and the angular sensitivity is explained qualitatively in terms of the Fresnel-Kirchhoff diffraction theory. The quantitative analysis is carried out using the coupled wave theory with the attenuated grating model. Experimental results obtained using a Kodak 649 F plate are compared with the theory. The bending is found to be zero at the emulsion surface and its shape was represented approximately by a quadratic curve in the direction of the emulsion thickness.
TL;DR: In this paper, a multiple scattering theory for a laser beam propagating in fogs is formulated in terms of the spatial-angle statistical distribution functions, and a series expansion in the order of multiplicity of the scattering events is obtained for the spectral radiance and irradiance.
Abstract: A multiple scattering theory for a laser beam propagating in fogs is formulated in terms of the spatial-angle statistical distribution functions. A series expansion in the order of multiplicity of the scattering events is obtained for the spectral radiance and irradiance. The advantage of the present method over the method of characteristics applied to the equation of radiative transfer is discussed. Numerical results for radiational and advective fogs are presented.
TL;DR: A systematic study to optimize the image in real optical systems, by fitting the filter transmission function on the exit pupil to different polynomial types is developed.
Abstract: A systematic study to optimize the image in real optical systems, by fitting the filter transmission function on the exit pupil to different polynomial types is developed. The systems we have treat...
TL;DR: In this article, the statistical properties of the amplitude and the intensity of a monochromatic speckle pattern as well as the behaviour of the spatial derivatives of these quantities are studied theoretically.
Abstract: The statistical properties of the amplitude and the intensity of a monochromatic speckle pattern as well as the behaviour of the spatial derivatives of these quantities are studied theoretically. Under the assumption of circular complex gaussian statistics general expressions are derived for the distribution density of the spatial derivative of the amplitude and the intensity of the speckle field. The spatial derivative of the real and the imaginary part of the amplitude is jointly gaussian distributed, whereas the distribution density of the spatial derivative of the intensity turns out to be of simple Laplacian form. Explicit formulas are given for speckle patterns produced by uniformly diffusing screens. Furthermore, the spatial density of level crossings of the intensity is investigated.
TL;DR: In this article, first-order statistics and temporal correlations of intensity fluctuations in stellar images and in the pupil plane are reported, and it is shown that measurements in the image plane are strongly dependent on the zenith angle.
Abstract: We report measurements of first-order statistics and temporal correlations of intensity fluctuations in stellar images and in the pupil plane. Measurements in the pupil plane are strongly dependent on zenith angle, whereas simultaneous measurements in the image plane show no such dependence.
TL;DR: In this article, general mathematical and numerical results for the excitation of an optical fiber by a plane wave focused through a lens are given for the effects on the coupling efficiency of transverse, longitudinal and angular misalignment of the lens and fibre axes.
Abstract: General mathematical and numerical results are given for the excitation of an optical fibre by a plane wave focused through a lens. Included are the effects on the coupling efficiency of transverse, longitudinal and angular misalignment of the lens and fibre axes. The accuracy of various approximations such as geometric optics in multimode fibres and gaussian modal fields in monomode fibres is also investigated.
TL;DR: In this paper, a toroidal mirror was used in conjunction with a spherical grating spectrometer for producing stigmatic images of small sources at various wavelengths in the region of grazing incidence from 10 to 300 +.
Abstract: A toroidal mirror can be used in conjunction with a spherical grating grazing incidence spectrometer for producing a stigmatic system. The aberrations of the configuration are considered; they set the limits of the performance of the system. It is, however, possible by choosing suitable optical parameters to have a system that produces stigmatic images of small sources at various wavelengths in the region of grazing incidence from 10 to 300 +. The aberrations are quite small and comparison with other devices used to get spatial and spectral resolution is good. The proposed configuration is considerably better at forming stigmatic images than the corresponding one that uses a toroidal grating.
TL;DR: In this paper, the study of infinitely conducting lamellar grating resonance anomalies is extended to arbitrary wavelengths and angles of incidence, and the behaviour of the trajectories is found theoretically and numerically.
Abstract: The study of the infinitely conducting lamellar grating resonance anomalies is extended to arbitrary wavelengths and angles of incidence, and the behaviour of the trajectories is found theoretically and numerically. The discussion of resonances for varying wavelength is unified with that for varying angle of incidence. The phenomena of ‘repulsion of anomalies’ and ‘exchange of identity’ are explained. Infinite conductivity results are compared with those for various finite conductivities, and it is shown that there is a close similarity between them, suggesting that the ideas developed for the former case have a wider validity. This is seen to be so when a brief survey is made of results for other grating profiles and arbitrary values of conductivity.
TL;DR: In this article, the development of optical waveguide lenses, including Luneburg, geodesic, Fresnel and Bragg grating lenses, is briefly reviewed chronologically, and a nearly diffraction-limited lens of the latter type can be obtained by using the shadow mask process.
Abstract: The development of optical waveguide lenses, i.e. mode-index (including Luneburg), geodesic, Fresnel and Bragg grating lenses is briefly reviewed chronologically. A Bragg lens and a Luneburg lens, fabricated by electron lithography and vacuum deposition respectively, are described. A nearly diffraction-limited lens of the latter type can be obtained by using the shadow mask process.
TL;DR: In this article, Planar Optical Waveguides and Fibres are used to construct planar optical waveguide and fiber optic networks, and planar waveguide-and-fiber pairs are discussed.
Abstract: (1979). Planar Optical Waveguides and Fibres. Optica Acta: International Journal of Optics: Vol. 26, No. 9, pp. 1132-1133.
TL;DR: In this paper, the analysis of a holographic beam expander which can, under perfect lossless conditions, convert a plane input beam into a plane diffracted beam, with a specified diffraction efficiency and beam width expansion ratio, is presented.
Abstract: The analysis of a holographic beam expander which can, under perfect lossless conditions, convert a plane input beam into a plane diffracted beam, with a specified diffraction efficiency and beam width expansion ratio, is presented. Using solutions of the coupled-wave differential equations of [2], the effects of average loss, and both constant and spatially dependent dephasing are studied. These solutions are also used to compare the properties of overlap gratings with Kogelnik's [1] results for infinite gratings, and to extend the analysis of [4] to lossy, dephased cases. The maximum possible diffraction efficiency of an absorption overlap grating is shown to depend on its shape and also to lie between the values for Kogelnik's reflection and transmission cases.