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Showing papers in "Optics and Laser Technology in 1977"


Journal ArticleDOI
TL;DR: The basic principles of optical methods for measuring voltage and current at high voltage are presented in this paper, including the magneto-optic effect, the electroelectrical effect and the electrogyration effect, plus various detection and noise reduction techniques.
Abstract: The basic principles of optical methods for measuring voltage and current at high voltage are presented. These include the magneto-optic effect, the electro-optic effect and the electrogyration effect, plus various detection and noise reduction techniques. Both free path and enclosed path devices which have been constructed on these principles are described. The viability of these devices for the electricity supply industry is assessed.

57 citations


Journal ArticleDOI
TL;DR: In this article, the authors discuss the use of electronic speckle pattern interferometry for optical NDT with a specially adapted closed circuit television system, giving on-line information.
Abstract: Interest in optical methods of NDT increased rapidly with the advent of holographic interferometry which made it possible to observe surface increments of less than 1 μm on practically any surface texture. Invariably the optical method is coupled with a mechanical loading cycle which tests the component directly in terms of its strength, a claim which cannot be made for most other NDT methods. Holographic interferometry is unfortunately slow and expensive to apply and other methods of optical examination based on coherent optical scattering have been investigated. Of particular interest in the author's laboratories is the technique of electronic speckle pattern interferometry. This technique enables a process directly comparable with holographic interferometry to be carried out with a specially adapted closed circuit television system, giving on line information. This work is discussed together with some other relevant processes and methods of optical NDT.

29 citations




Journal ArticleDOI
TL;DR: In this article, factors affecting the stability of evaporated thin film filters are reviewed, and emphasis is placed on laser damage resistance, mechanical durability, and water adsorption, with a focus on the laser effect.
Abstract: Factors affecting the stability of evaporated thin film filters are reviewed. Emphasis is placed on laser damage resistance, mechanical durability, and water adsorption.

14 citations


Journal ArticleDOI
TL;DR: The three basic methods of linear laser spectroscopy are reviewed: absorption, opto-acoustic, and fluorescence as discussed by the authors, and the characteristics of each method and their areas of application are presented and compared.
Abstract: The three basic methods of linear laser spectroscopy are reviewed: absorption, opto-acoustic, and fluorescence spectroscopy The characteristics of each method and their areas of application are presented and compared

14 citations


Journal ArticleDOI
TL;DR: In this article, all-glass rotating diffraction gratings developed for use as beam splitting frequency shifters in laser Doppler anemometers are described, which are produced using etching techniques and can be exposed to high power laser beams.
Abstract: All-glass rotating diffraction gratings developed for use as beam splitting frequency shifters in laser Doppler anemometers are described. The gratings are produced using etching techniques and can be exposed to high power laser beams. Advantages of using these gratings in optical arrangements are that they are simple to set-up and easy to align.

13 citations


Journal ArticleDOI
TL;DR: In this paper, the authors describe the mastering and replication of video discs and emphasize the critical parameters involved in the process, which is referred to as the laser laser beam mastering.
Abstract: The mastering and replication of video discs is described. Mastering involves exposing a photoresist-coated plate to a focused, modulated laser beam. After development, a layer of nickel is grown on the photoresist surface. The nickel layer forms a negative copy of the master plate. This nickel copy may then be used to emboss into plastic sheet a positive replica of the original master. This paper emphasizes the critical parameters involved in the process.

10 citations


Journal ArticleDOI
TL;DR: This report presents theoretical information on an analysis technique for extracting the complex speckle information from the photographs, using partially coherent light to create virtual fringes on the phtographs, originating from Young's fringes.
Abstract: Defocused speckle photography is a new inspection technique for recording topological changes on engineering structures — giving information on bulges, plastic deformations, etc. Recording the photographs is a relatively simple technique. In this report we present theoretical information on an analysis technique for extracting the complex speckle information from the photographs. Partially coherent light is used to create virtual fringes on the phtographs, originating from Young's fringes. This analysis procedure is highly sensitive — probably better than holography — and also has a wide measurement range. We present a mainly theoretical description of the technique aimed at practical engineering applications.

9 citations


Journal ArticleDOI
TL;DR: In this paper, the dielectric constant, pyroelectric coefficient, and loss tangent of triglycine sulphate (TGS) crystals that had been poled and subsequently irradiated with x-rays are presented as a function of x-ray exposure and temperature.
Abstract: The dielectric constant, pyroelectric coefficient, and loss tangent of triglycine sulphate (TGS) crystals that had been poled and subsequently irradiated with x-rays are presented as a function of x-ray exposure and temperature. The results are compared with similar measurements made on poled Co 60 gamma irradiated TGS. An estimated x-ray dosage of 1.5−2.0 × 10 6 R min -1 for 1–2 min gave equivalent results to 2.3 Mr of Co 60 gamma rays in achieving optimum non-ferroelectric pyroelectric in TGS ir detectors.

8 citations


Journal ArticleDOI
TL;DR: In this article, a method of measuring optical phase differences caused by the presence of optical path differences between two coherent light beams is reported, where a polarization technique is used and the phase differences are detected as rotation angles of the plane of polarization.
Abstract: A method of measuring optical phase differences caused by the presence of optical path differences between two coherent light beams is reported. A polarization technique is used and the phase differences are detected as rotation angles of the plane of polarization. The sensitivity of the method is better than 10 -4 λ and the stability is 3 X 10 -4 λ per minute. These limitations result from thermal fluctuations of the order of 10 -3 °C. A higher sensitivity of about 10 -5 λ, or better, is expected if the effect due to thermal fluctuations can be reduced.

Journal ArticleDOI
TL;DR: In this article, a process of granularity growth in partially developed speckle patterns produced in the near field of wavy object surfaces illuminated using a laser has been experimentally studied by investigating the probability density function and average contrast of their intensity variations.
Abstract: A process of granularity growth in partially developed speckle patterns produced in the near field of wavy object surfaces illuminated using a laser has been experimentally studied by investigating the probability density function and average contrast of their intensity variations. These parameters have been measured as a function of the distance from the object surface to the detector for four typical sample objects having different surface qualities. It has been found that the variation in average speckle contrast with receiving distance is strongly dependent on the surface quality of the objects. The saturated value of the speckle contrast, found from the graph of its dependence on receiving distance, is also related to the maximum height of irregularities in the surface.



Journal ArticleDOI
TL;DR: In this paper, a theory of small-angle scattering is presented, and the photon dispersion partial differential equation is derived and the dispersion coefficient characterizing the medium is introduced.
Abstract: A theory of random small-angle scattering is presented The photon dispersion partial differential equation is derived and the dispersion coefficient characterizing the medium is introduced The equation is solved for a spatial impulse The modulation transfer function and the contrast loss are derived as a funcion of spatial frequency, dispersion coefficient, and object-to-image distance The limitation on resolution is shown by an indeterminancy relation based on the dispersion coefficient The dispersion angle (rms value of scattering angle) is calculated as an example

Journal ArticleDOI
TL;DR: In this paper, the frequency doubled Nd-YAG laser was used for transferring wideband data from one satellite to another, and the NdYAG was tested in space at a rate of 1 000 Mbit s-1.
Abstract: Space laser communications with the frequency doubled Nd-YAG laser offers the most efficient means for transferring wideband data from one satellite to another. A space test in 1981 of the Nd-YAG laser system operating at a rate of 1 000 Mbit s-1 will establish the basis for future systems. The system offers growth capability beyond conventional systems and is a major step forward in the application of a low power laser. The Nd-YAG laser design as well as its principles of operation are constrained by the space application. The laser is now conductively cooled, mode-locked, and frequency-doubled, and will be so operated in space. The space system will use both solar and lamp pumped lasers to allow alternate modes of operation.



Journal ArticleDOI
TL;DR: In this article, the possibility of using an electro-optical frequency modulator with a rotating electric field (Mthis article) in LDV is discussed, and prototype systems measuring one component of the velocity vector are described.
Abstract: The possibility of using an electro-optical frequency modulator with a rotating electric field (MREF) in LDV is discussed. Prototype systems measuring one component of the velocity vector are described. Photographs of the experimental signals obtained are given.

Journal ArticleDOI
TL;DR: In this article, a laser velocimeter is described which uses an optical Doppler frequency discriminator in the form of a spherical mirror confocal Fabry-Perot interferometer (SFPI).
Abstract: A laser velocimeter is described which uses an optical Doppler frequency discriminator in the form of a spherical mirror confocal Fabry-Perot interferometer (SFPI). The SFPI pass band is made to coincide with the laser frequency using a system of external control. Experimental results are given.

Journal ArticleDOI
TL;DR: Laser facsimile printing comprises real-time diffraction-limited laser reading, transmission, and printing of large sized images as discussed by the authors, which uses special metal coated laser lithoplates and a laser to create diffraction limited "holes" in the thin metal films which encompass the printing elements of the Facsimile process.
Abstract: Laser facsimile printing comprises real-time diffraction-limited laser reading, transmission, and printing of large sized images. It uses special metal coated laser lithoplates and a laser to create diffraction-limited ‘holes’ in the thin metal films which encompass the printing elements of the facsimile process.

Journal ArticleDOI
TL;DR: In this article, a modified Fizeau interferoscope was developed for testing aircraft camera windows measuring up to 60 cm in diameter, where relatively cheap components were used for the large collimating lens and reference flats, and a small holographic optical element corrected the residual errors of form.
Abstract: This paper describes a modified Fizeau interferoscope which has been developed for testing aircraft camera windows measuring up to 60 cm in diameter. Relatively cheap components are used for the large collimating lens and reference flats, and a small holographic optical element corrects for the residual errors of form.

Journal ArticleDOI
TL;DR: The use of photodichroic alkali halide crystals as re-usable input, storage, and filter plane elements in a coherent optical computer is reviewed in this paper, with emphasis on the use of the M and MA centres in NaF at room temperature.
Abstract: The use of photodichroic alkali halide crystals as re-usable input, storage, and filter plane elements in a coherent optical computer are reviewed. Various recording methods and applications are presented with emphasis on the use of the M and MA centres in NaF at room temperature.


Journal ArticleDOI
TL;DR: In this paper, the first in a series of articles reviewing the subject of laser spectroscopy is presented, followed by an outline of the present status of tunable lasers, the basic instruments used in developing the techniques of laser Spectroscopy.
Abstract: Laser spectroscopy has made it possible to solve, or at least to begin solving, a number of important problems to which classical spectroscopy could not be applied. These problems are defined in this, the first in a series of articles reviewing the subject of laser spectroscopy. This is followed by an outline of the present status of tunable lasers — the basic instruments used in developing the techniques of laser spectroscopy.

Journal ArticleDOI
TL;DR: In this paper, classical signal processing techniques for overcoming this noise are reviewed and their application to a time signal obtained from an optical signal is studied by considering their application in optical metrology applications.
Abstract: In optical metrology applications which use temporal modulation, a measurement is obtained from an electrical signal which is periodical in time. A single component provides the required measurement of the optical variable. Consequently, it is necessary to filter out this component and measure its power. This power decreases with measurement accuracy and is smaller than the total random noise power. Classical signal processing techniques for overcoming this noise are reviewed. In practice these techniques differ from their theoretical descriptions. They are therefore studied by considering their application to a time signal obtained from an optical signal.




Journal ArticleDOI
TL;DR: In this paper, the authors examined the birefringence effects of estar base film, used almost exclusively in aerial reconnaissance work, when such film is placed in the signal path.
Abstract: Coherent optical correlators using Fourier transform matched filters are generally constructed using the interference between a transformed signal beam and an equipolarized collimated coherent reference beam. Polarization effects of any system elements must be accounted for in using such a correlator, or in any system using holographic techniques, particularly if analysers are used. Birefringence effects of estar base film, used almost exclusively in aerial reconnaissance work, have been examined by the authors when such film is placed in the signal path. Methods of compensation for such effects are suggested.