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Showing papers in "Optics and Laser Technology in 1974"


Journal ArticleDOI
TL;DR: A brief survey of the principles and present state of the art in laser Doppler anemometry is given in this paper, where both the optical and signal processing aspects are treated in some detail.
Abstract: A brief survey is given of the principles and present state of the art in laser Doppler anemometry. Both the optical and signal-processing aspects are treated in some detail. The comparative features and special problems associated with the various methods of interpreting the Doppler signals are discussed, with particular reference to the more recently developed technique of photon correlation. A wide range of practical applications, including measurements on liquids and solids, is considered.

102 citations


Journal ArticleDOI
TL;DR: In this article, the mechanism, parameters, and advantages for the surface hardening of steels are outlined and test results described, and uses of lasers for de-scaling and the bonding of powders to metal surfaces are also proposed.
Abstract: Surface treatments practicable with multi-kilowatt, continuous laser beams are considered. In particular, the mechanism, parameters, and advantages for the surface hardening of steels are outlined and test results described. The uses of lasers for de-scaling and the bonding of powders to metal surfaces are also proposed.

28 citations


Journal ArticleDOI
TL;DR: In this article, a quantitative analysis of cutting thin stainless steel sheets with cw CO 2 lasers using an oxygen gas jet assist is reported, and results are interpreted theoretically using a point source model.
Abstract: A quantitative analysis of cutting thin stainless steel sheets with cw CO 2 lasers using an oxygen gas jet assist is reported. Results are interpreted theoretically using a point source model.

23 citations


Journal ArticleDOI
TL;DR: In this article, the principles of thick hologram theory are discussed and some materials which can be used as thick recording media are described, and a survey of the existing and future applications for thick holograms is presented.
Abstract: Many workers are turning away from holograms made with thin photographic emulsions and are investigating ‘thick’ holograms, with their exciting potential of high diffraction efficiency, increased information storage capacity, reduced noise, and increased spectral or angular discrimination. This article discusses the principles of thick hologram theory, and describes some of the materials which can be used as thick recording media. Advantages and limitations of thick holograms are illustrated by experimental examples. The article concludes with a survey of the existing and future applications for thick holograms.

19 citations


Journal ArticleDOI
TL;DR: It is shown that afocal lens systems with unit magnification can be used to monitor displacement and tilt of an object moving in a straight line.
Abstract: It is shown that afocal lens systems with unit magnification can be used to monitor displacement and tilt of an object moving in a straight line. The lens systems can be incorporated in double-ended optical alignment systems using visual or photo-electric read-out, and have potential applications in machine tool control.

13 citations



Journal ArticleDOI
G.K. Megla1
TL;DR: In this article, a brief description of the characteristic properties of photochromic glass and some applications which illustrate its potential and its inherent limitations is presented. But the application of the glass is not discussed.
Abstract: Photochromic glass has developed into an optical component which can be used to advantage in optical systems. After a brief description of the characteristic properties of the glass, some applications which illustrate its potential and its inherent limitations is practice are detailed. These include digital storage, use in a cathode ray tube, contrast enhancement, and hologram storage.

8 citations



Journal ArticleDOI
TL;DR: Present and potential applications of high-power gas lasers to such diverse areas as industrial systems (alignment, Raman scattering, Doppler velocimeters, materials processing, etc), isotope-separation, thermonuclear fusion, and military applications are discussed.
Abstract: Present and potential applications of high-power gas lasers to such diverse areas as industrial systems (alignment, Raman scattering, Doppler velocimeters, materials processing, etc), isotope-separation, thermonuclear fusion, and military applications are discussed. Different operational characteristics are required for various laser applications, and these are described. A brief introduction to the general characteristics of gas lasers is given; and to gas-dynamic, electrical, and chemical methods of excitation.

7 citations


Journal ArticleDOI
TL;DR: In this article, two heterodyne laser anemometers incorporating frequency pre-shifting are described, where a thin scattering disc provides scattered light from a focused laser beam to form a reference beam whose frequency can be shifted by rotating the disc.
Abstract: Two heterodyne laser anemometers incorporating frequency pre-shifting are described. A thin scattering disc provides scattered light from a focused laser beam to form a reference beam whose frequency can be shifted by rotating the disc. The method is both simple and inexpensive. It extends the range of laser velocity measurements, removes directional ambiguity, and facilitates estimations of instrumental broadening. The instruments are analysed, compared with conventional anemometers, and their range and capability demonstrated.

7 citations


Journal ArticleDOI
TL;DR: In this article, a holographic technique is described whereby a 35 mm camera lens is used in conjunction with its own film to measure focusing errors and other symmetric aberrations.
Abstract: A holographic technique is described whereby a 35 mm camera lens is used in conjunction with its own film to measure focusing errors and other symmetric aberrations. The method relies on photographing a scatter-plate whose fabrication is described. Results are presented showing how four different camera systems perform at various field angles.

Journal ArticleDOI
TL;DR: A general review of the properties of self-scanned photo-diode arrays is given in this paper, where the mechanisms of charge storage, scanning, and signal processing are described and a discussion of the electrical, optical, and noise characteristics of the devices are discussed.
Abstract: A general review of the properties of self-scanned photo-diode arrays is given. The mechanisms of charge storage, scanning, and signal processing are described and this is followed by a discussion of the electrical, optical, and noise characteristics of the devices. The final section presents a variety of current industrial applications.

Journal ArticleDOI
TL;DR: In this article, a simple spark gap capable of switching high voltages up to 30 kV at a repetition rate as high as 100 Hz was described, without any failure for several months.
Abstract: This describes a very simple spark gap capable of switching high voltages up to 30 kV at a repetition rate as high as 100 Hz. The device has been working without any failure for several months.

Journal ArticleDOI
TL;DR: In this article, a fiber optic delivery system has been used in laser welding of metals, which has a length of 140 cm and can transmit pulsed energies from a Nd-YAG laser with an efficiency of 85%.
Abstract: A fibre optic delivery system has for the first time been used in laser welding of metals. The optical fibre is flexible and has a length of 140 cm. It can transmit pulsed energies from a Nd-YAG laser in excess of 25 J with an efficiency of 85%. Potential applications in industry and in dentistry are discussed.


Journal ArticleDOI
TL;DR: In this article, a structure dynamic model of an airplane fin built by Saab-Scania, Sweden, has been vibration tested by the holographic time-average technique, and the inner structure of the fin model was revealed by inducing a temperature difference between the two exposures of a double-exposed hologram.
Abstract: A structure dynamic model of an airplane fin built by Saab-Scania, Sweden, has been vibration tested by the holographic time-average technique. The investigation was performed at Volvo-Flygmotor, Sweden, in their vibration laboratory. Holograms were made at every resonance frequency and, in all, eleven different patterns were created in the interval from 0 to 3 400 Hz. The inner structure of the fin model was revealed by inducing a temperature difference between the two exposures of a double-exposed hologram.

Journal ArticleDOI
TL;DR: In this article, the basic forms of the optical systems of laser Doppler velocimeters with supression of the additive noise component in the output signal are investigated by the Jones matrix method.
Abstract: Basic forms of the optical systems of laser Doppler velocimeters with supression of the additive noise component in the output signal are investigated by the Jones matrix method. The expressions for the resulting Doppler signal, taking into account the parameters and orientation of phase elements and the receiving polarization analyser, have been obtained and analysed. Experimental results are given.

Journal ArticleDOI
TL;DR: In this paper, a compact battery-operated Nd-YAG laser is described which is capable of giving a free-running output energy of over 05 J. The device is able of making small welds and punching small holes in metal foil constructional details, a circuit diagram and operating data are given.
Abstract: A compact battery-operated Nd-YAG laser is described which is capable of giving a free-running output energy of over 05 J The device is capable of making small welds and of punching small holes in metal foil Constructional details, a circuit diagram and operating data are given

Journal ArticleDOI
TL;DR: Holographically made components can be used in two types of interferometers: lateral shear and radial shear instruments as discussed by the authors, and they have been shown to have advantages which may extend their use.
Abstract: Holographically made components can be used in two types of interferometer: lateral shear and radial shear instruments. The principles, construction, and performance of these are described and examples of interferograms given. The holographic interferometers are shown to have advantages which may extend their use.

Journal ArticleDOI
TL;DR: In this article, a He-Ne laser source is used and the component to be tested acts as an interferometer to test the parallelism of glass blocks, the 90° angle error and pyramidal error of a porroprism, and the error in the 45° angles of a right angle prism.
Abstract: Examples are given of a quick and convenient method of testing optical components: the parallelism of glass blocks; the 90° angle error and pyramidal error of a porroprism; and the error in the 45° angles of a right angle prism. A He-Ne laser source is used and the component to be tested acts as an interferometer.

Journal ArticleDOI
TL;DR: The principle of beam-addressed holographic Memories is outlined and existing data memories are considered in relation to future holographic memories, and two basic approaches to fast gigabyte memories are discussed.
Abstract: The principle of beam-addressed holographic memories are outlined and existing data memories are considered in relation to future holographic memories. The next objective is to expand the capacity to the gigabyte region while maintaining read—write access times of about 100 μs. In view of the limitations imposed by conventional storage techniques, two basic approaches to fast gigabyte memories are discussed. On reasonable approach is to design modular systems comprising a number of storage modules of variable capacity. The other is to reach the gigabyte region by using multiple exposure techniques. Besides block-organized memories, bit-organized and byte-organized holographic memories with transported storage media are considered as possible alternatives to conventional memories with magnetic tapes, discs, and drums.

Journal ArticleDOI
TL;DR: In this article, a technique for measuring the dynamic behavior of concrete piles during driving operations using a He-Cd laser is reported. But this technique is not suitable for outdoor applications.
Abstract: A technique for measuring the dynamic behaviour of concrete piles during driving operations using a He-Cd laser is reported. Traces of pile movement are recorded on photo-sensitive oscillograph paper which is attached to the pile and exposed to a laser beam transmitted from a fixed point. The oscillograph paper is filtered against the background daylight but is sensitive to the wavelength of the laser at around 441.6 nm. Using this technique clear traces of the rebounding of concrete piles have been obtained in daylight.



Journal ArticleDOI
TL;DR: The application of time-averaged holography to the non-destructive testing of CRT faceplates is described in this article, where the antinodes revealed by the fringe patterns have been found to correspond to the weakest points on the faceplates.
Abstract: The application of time-averaged holography to the non-destructive testing of CRT faceplates is described. The antinodes revealed by the fringe patterns have been found to correspond to the weakest points on the faceplates. The relative strengths of different CRTs can be deduced from the number of fringes obtained when they are vibrated over a range of amplitudes. The information can aid designers of new types of CRT.

Journal ArticleDOI
TL;DR: Theoretical aspects of producing laser plasmas are considered: the characteristics of the plasma, the transfer of laser energy to the material, and the different mechanisms of heating as discussed by the authors, and the high power lasers required are described.
Abstract: Theoretical aspects of producing laser plasmas are considered: the characteristics of the plasma, the transfer of laser energy to the material, and the different mechanisms of heating. The high power lasers required are described. Details are given of the arrangement used at Limeil in experiments to find evidence of nuclear fusion produced by a laser beam, and some results presented. Limiting factors in the experiments are discussed.

Journal ArticleDOI
TL;DR: In this paper, the authors used flat glass plates and aluminium rings to generate spherical surfaces with radii of curvature from 3 to 10 m. But the experimentally measured radii and those predicted theoretically differ by a factor of three.
Abstract: Optical quality spherical surfaces have been generated by a technique which involves the differential contraction of two components bonded together at an elevated temperature. Preliminary experiments using flat glass plates and aluminium rings are described. Concave and convex surfaces have been produced with radii of curvature from 3—10 m. A theoretical analysis of the composite structure is given: the experimentally measured radii and those predicted theoretically differ by a factor of three.

Journal ArticleDOI
TL;DR: In this article, a technique using moire fringe formation by rotating the reference wave in one exposure of the double exposure method was found to be most suitable for this purpose, and high contrast and multiplication of moire fringes can be obtained by a moire mesh sharpening and multiplication method.
Abstract: Some optical differential interferometric techniques were investigated in order to measure the density distribution in the air jet flow of a small scale flow cell while excluding the effects of the optical distortion of its glass windows. A technique using moire fringe formation by rotating the reference wave in one exposure of the double exposure method was found to be most suitable for this purpose. High contrast and multiplication of moire fringes can be obtained by a moire fringe sharpening and multiplication method.