Showing papers in "Optics and Laser Technology in 1978"
TL;DR: In this article, the incorporation of a pulsed ruby laser into an electronic speckle pattern interferometer was described for observing vibrational and transient events with a double pulsed laser and some typical results were given.
Abstract: This paper describes the incorporation of a pulsed ruby laser into an electronic speckle pattern interferometer. A technique is described for observing vibrational and transient events with a double pulsed laser and some typical results are given. Results of the application of the interferometer to non-destructive testing are included.
65 citations
31 citations
TL;DR: In this paper, the feasibility of using a fiber optic for transmitting laser light to a vibrating object and scattered light back to a laser-Doppler unit, has been demonstrated, and a new mode of operation of laser Doppler equipment has been devised with marked improvement over the usual Twyman-Green mode.
Abstract: The feasibility of using a fibre optic for transmitting laser light to a vibrating object and scattered light back to a laser-Doppler unit, has been demonstrated. A new mode of operation of laser-Doppler equipment has been devised with marked improvement over the usual Twyman-Green mode. With the aid of this fibre optic laser-Doppler system both frequency and amplitude information can be obtained from otherwise inaccessible machine components.
18 citations
TL;DR: In this paper, the absorption coefficients of NO2 at wavelengths suitable for the operation of differential absorption lidar (DIAL) systems, at around 446 nm and 489 nm, are reported.
Abstract: Laboratory measurements of the absorption coefficients of NO2 at wavelengths suitable for the operation of differential absorption lidar (DIAL) systems, at around 446 nm and 489 nm are reported. Such measurements are necessary for the valid determination of absolute levels of concentration of NO2 in the atmosphere and have been made in order to assess anomalies in existing data. A theoretical assessment of some of the optional systems currently available for the application of DIAL to the measurement of atmospheric concentrations of SO2 is described.
14 citations
TL;DR: In this article, a thickness gauge based on channelled spectrum phenomena is described, which can be extended to the determination of any absolute optical delays; applications dealing with surface roughness testing and control of the dimensional stability of silicon rubbers are mentioned.
Abstract: A thickness gauge based on channelled spectrum phenomena is described. Compared with other interferometric systems, the instrument is characterized by its low cost while retaining a high sensitivity and a wide range of measurement. Its use can be extended to the determination of any absolute optical delays; applications dealing with surface roughness testing and control of the dimensional stability of silicon rubbers are mentioned.
14 citations
TL;DR: In this paper, the properties of passively and actively mode-locked dye lasers are described and compared, and methods of measuring pulse duration and applications of these lasers to photophysics and photobiology are discussed.
Abstract: Continuously working dye lasers have produced pulses as short as 0.3 ps. The properties of passively and actively mode-locked dye lasers are described and compared. Methods of measuring pulse duration and applications of these lasers to photophysics and photobiology are discussed.
12 citations
TL;DR: In this article, a study of droplets under conditions in which the surface tension effect is large is presented, where an interaction between the droplet shape and the forces acting on it, resulting in some interesting optical properties are illustrated.
Abstract: Recent work has shown how study of the motion of oil films on vertical surfaces under gravity can be used in viscosity measurements. Over most of such a film, the profile is determined almost entirely by the viscosity but at both upper and lower edges the effect of surface tension is appreciable. This paper presents a study of droplets under conditions in which the surface tension effect is large. There is then an interaction between the droplet shape and the forces acting on it, resulting in some interesting optical properties which are illustrated in the paper.
12 citations
TL;DR: In this article, special molding techniques result in single-and multi-element optical systems which can create entirely new options for both optical designers and production engineers, which can be used for both single and multi-layer optical systems.
Abstract: Special moulding techniques result in single- and multi-element optical systems which can create entirely new options for both optical designers and production engineers.
11 citations
8 citations
TL;DR: In this article, a method for measuring very high viscosities, up to 1015 poise, or higher, using a holographic double exposure technique has been proposed and compared with those obtained with the usual technique, showing that their method gives the correct results.
Abstract: We describe a holographic method for measuring very high viscosities, up to 1015 poise, or higher. The method consists of detecting small displacements, due to the sample deformation, by the holographic double exposure technique. Measurements performed on amorphous selenium are reported and compared with those obtained with the usual technique, showing that our method gives the correct results. The advantages of the proposed technique are briefly discussed.
8 citations
TL;DR: In this paper, the spectral response of p-Ge photon drag and n-Gap photon drag-optical rectification detectors have been extended to the wavelength range between 2 and 11 μm.
Abstract: Previous studies of the spectral response of p-Ge photon drag and n-Gap photon drag-optical rectification detectors have been extended. Measurements have also been made of the spectral response of p-Si photon drag, p-GaP photon drag-optical rectification and p-GaAs photon drag-optical rectification detectors. The wavelength range of main interest is between 2 and 11 μm, (HF, HCl, HBr, H 2 O vapour and CO 2 lasers), but some measurements have also been made at 28 and 33 μm, (H 2 O vapour laser).
TL;DR: In this article, the techniques of laser doppler and time of flight anemometry have been combined in a single instrument, which has led to a most versatile optical anemometer system.
Abstract: The techniques of laser doppler and time of flight anemometry have been combined in a single instrument. The operation has led to a most versatile optical anemometry system.
TL;DR: It is found that relatively good images are reconstructed from the computer-generated holograms proposed here.
Abstract: New simple computer-generated holograms displayed by an x-y plotter are proposed and investigated. In the construction of holograms by computer, phase coding methods are used in order to distribute the Fourier-transform values of an original object over the whole of the receiving plane where the hologram is to be constructed. It is found that relatively good images are reconstructed from the computer-generated holograms proposed here.
TL;DR: The field of ultra-violet/visible gas lasers has undergone a rapid expansion in the past three years since the discovery of the first rare gas monohalide excimer laser as mentioned in this paper.
Abstract: The field of ultra-violet/visible gas lasers has undergone a rapid expansion in the past three years since the discovery of the first rare gas monohalide excimer laser. There are now many new high power ultra-violet and visible lasers available with demonstrated efficiencies exceeding 1%. This review of the field emphasises the common properties of these laser systems and indicates their potential impact on commercial photochemical processes.
TL;DR: In this paper, the authors discuss the recent achievements, new possibilities, and prospects for the selective detection of ultra-low concentrations of atoms and molecules by laser radiation, and present methods of detecting atoms.
Abstract: This article discusses the recent achievements, new possibilities, and prospects for the selective detection of ultra-low concentrations of atoms and molecules by laser radiation The first part of the article considers methods of detecting atoms The far more difficult case of selective detection of polyatomic molecules is the subject of the second part of the article
TL;DR: In this paper, the most important characteristics of laser-based materials processing applications (in particular argon-ion, Nd-YAG, and CO 2 ) are reviewed, with special emphasis on the importance of the electrical efficiency of such systems.
Abstract: Lasers are being used increasingly for specialized engineering applications such as the drilling and scribing of ceramics, and the profile cutting, welding and surface heat-treatment (hardening, alloying and splat-quenching) of metals. The most important characteristics of lasers used for these materials- processing applications (in particular argon-ion, Nd-YAG, and CO 2 ) are reviewed, with special emphasis on the importance of the electrical efficiency of such systems. The article concludes with a summary of the current status of industrial multi-kilowatt CO 2 lasers, which are of particular interest for metal-working applications.
TL;DR: In this paper, an automated system that precisely measures the spectral loss of optical fibres at wavelengths from 0.63 μm to 1.51 μm has been developed, along with measurement techniques used and typical results.
Abstract: An automated system that precisely measures the spectral loss of optical fibres at wavelengths from 0.63 μm to 1.51 μm has been developed. A description of the system, along with measurement techniques used and typical results are given in this paper.
TL;DR: In this paper, an extension of the cw laser action down to 220nm has been presented, with the focus on the 780 nm transition of Cu II, achieving metal densities of 1014 atoms cm-3 without using external ovens or discharge heating.
Abstract: Cw laser action has been extended down to 220nm. Moreover, cw oscillation has been obtained on twenty additional transitions in the spectral range between 220 and 320 nm. Ultra-violet laser thresholds as low as 2 A have been observed. In comparison, rare gas ion lasers require 20 to 50 A to reach threshold. Metals of interest are sputtered into the discharge giving metal densities of 1014 atoms cm-3 without using external ovens or discharge heating. Recent attempts to scale the output power levels to 1 W cw are presented with particular emphasis on the 780 nm transitions of Cu II.
TL;DR: In this article, a circularly polarized light wave is transmitted through the flow-birefringent medium, and the transmitted elliptically polarized wave is compensated by a Babinet-Soleil plate to convert it back into a roundly polarized wave.
Abstract: A method of measuring flow-birefringence is reported. In this method, a circularly polarized light wave is transmitted through the flow-birefringent medium. The transmitted elliptically polarized wave is compensated by a Babinet-Soleil plate to convert it back into a circularly polarized wave. The state of circular polarization is confirmed using the rotating-analyser method. Measurements can be carried out with a sample having a fixed azimuth. The minimum detectable optical retardation angle was 5 × 10 -3 degree. This corresponds to a birefringence of Δ n = 1 × 10 -10 , when the optical path length of the sample cell is 100 mm.
TL;DR: In this paper, a review of multiphoton and multistep spectroscopy of atoms and molecules is presented, which relies almost exclusively on the application of tunable lasers.
Abstract: Multiphoton and multistep spectroscopy of atoms and molecules is a rapidly developing branch of laser spectroscopy which relies almost exclusively on the application of tunable lasers. This article reviews the different techniques which have been developed.
TL;DR: In this paper, a new technique for high-speed optoelectronic modulation and switching of dc or rf signals up to the GHz range, using fast laser-controlled silicon microstrip devices, has been developed.
Abstract: A new technique for high-speed optoelectronic modulation and switching of dc or rf signals up to the GHz range, using ‘fast’ laser-controlled silicon microstrip devices, has been developed. The technique is based on well known applications of photosensitive CdS or Si devices as switching or triggering elements in ‘slow’ circuitry. The switching actions are achieved via laser- excited highly conductive solid-state plasmas. Applying nanosecond or picosecond laser pulses permits dc pulses or microwave pulses as short as a single cycle to be generated, demonstrating the practical significance of laser application in future pulse shaping and sampling techniques.
TL;DR: In this paper, the authors present two new applications for light-induced reactions: surface photochemistry and photodesorption, both of which are applicable to photochemical synthesis of compounds and separation of chemical or isotope mixtures.
Abstract: Use of light to promote chemical reactions has been studied for a long time. The fact that solar energy is a primary ingredient of all forms of fuel, from combustible materials to wind power (excluding nuclear), together with the impending energy shortage has brought about a resurgence of interest in photochemistry. The development of the laser has resulted in the pursuit of new methods of isotope separation. This paper presents two new applications for light-induced reactions: surface photochemistry and photodesorption. Both are applicable to photochemical synthesis of compounds and separation of chemical or isotope mixtures. Emphasis is given to the more demanding isotope separation aspects of surface photochemistry and photodesorption. Conditions for chemical synthesis or chemical separation are treated as a logical extension of the isotope separation treatment.
TL;DR: In this article, a computer program has been formulated to plot the two sheets of a caustic separately, each as a stereo pair, for diagnosing and correcting image errors in the process of designing an optical system.
Abstract: The caustic surface can be a useful tool for diagnosing and correcting image errors in the process of designing an optical system. However, because of their complicated structure, caustics are hard to visualize. Therefore, a computer programme has been formulated to plot the two sheets of a caustic separately, each as a stereo pair. Results obtained for a simple plano-convex lens are presented.
TL;DR: In this paper, various methods and areas of application are classified and compared, and some experiments and results are mentioned for illustration, and a classification of the methods and their applications is given.
Abstract: Picosecond laser spectroscopy is a rapidly developing field, the applications of which extend to the adjacent subjects of chemistry and biology. Here, the various methods and areas of application are classified and compared. Some experiments and results are mentioned for illustration.
TL;DR: In this paper, the main ideas, methods and types of nonlinear laser spectrometers used for atomic and molecular spectroscopy without Doppler broadening are discussed and discussed.
Abstract: This paper in the series gives a brief outline of the main ideas, methods and types of nonlinear laser spectrometer used for atomic and molecular spectroscopy without Doppler broadening This is the most developed area of laser spectroscopy and has recently been the subject of several papers 1,2 to which readers are reffered for more detailed information
TL;DR: In this paper, the application of lasers in Raman spectroscopy was reviewed and compared with the use of traditional laser-assisted spectroscopic methods, and the results showed that laser-based techniques outperformed traditional methods.
Abstract: This article in the series reviews the application of lasers in Raman spectroscopy.