Showing papers in "Optics and Lasers in Engineering in 1985"

TL;DR: Projection etching techniques using 308 nm and 248 nm excimer laser illumination have been investigated as a means of micromachining thin free-standing polymer films as discussed by the authors, where consideration is given to the choice of operating parameters (wavelength, fluence) to minimise damage to the machined structures.

TL;DR: In this paper, a method based on objective laser speckles for the measurement of ultra-low thermal expansion is described, where the sensitivity is obtained by the rotation of a probe due to differential thermal expansion of the sample and reference rods.

TL;DR: In this article, the authors show that the transition zone in the concluding diagram of Swift-Hook and Gick: "dimensionless welding speed/dimensionless power" is linear when the logarithmic scales are abandoned.

TL;DR: A new method for the automatic processing of Young's fringes in speckle photography is described, based on the technique of spatial phase detection, which reduces the amount of calculation, yet accuracy is of an order comparable with that of the Fourier transform method.

TL;DR: In this paper, experiments with CO 2 and YAG lasers were carried out on carbon and stainless steels and two distinct regimes were identified in the gas jet assisted cutting process and in both cases predictions of working parameters can be made.

TL;DR: In this article, the electronic speckle pattern interferometry (ESPI) was used to detect debonded areas with certain limitations, which depend on the size of the defect and the thickness of metal used.

TL;DR: In this article, a finite element analysis of the temperature distribution around a moving point heat source is carried out with a single step solution using a computer program based on standard finite element library subroutines.

TL;DR: In this article, a near-infrared absorption method employing a 2-km long low-loss silica optical-fibre link in conjunction with an InGaAs light emitting diode at 1.68 μm was realized in real time by a fully optical remote detection system for propane gas.

TL;DR: In this article, three methods for strain measurement are described: speckle shearing interferometry (SSI), electrical strain gages and mechanical deflectometers; they were compared to the analytical method based on the theory of elasticity.

TL;DR: In this article, the application of the sandwich technique to the vibration analysis performed by stroboscopic hologram interferometry is presented, where the image reconstructed from the sandwich hologram replaced in its original position gives the same fringes of classic double exposure holography, and the reconstruction with sandwich tilting allows the determination of the sign of the vibration phase by observing the distortion of the fringe pattern.

TL;DR: In this article, a method for measuring a displacement vector using a single hologram is discussed, which realizes the measurement by observing the object through three or more points on the hologram with a single lens and using a heterodyne technique to detect accurate phase differences.

TL;DR: In this article, the principal stress distribution in a semi-infinite plate with a rectangular hole during the propagation of a stress wave was solved using a polyester model having a partially reflecting front surface and a double-pulse Ruby laser, each pulse having an energy of 0·5 J.

TL;DR: In this paper, an electro-optical sensor for microdisplacement measurements based on the triangulation principle has been reported, and the theory of the error in measurements arising due to the tilt of the object surface and misalignment of illuminating and detecting arms of the system is discussed.

TL;DR: A new Speckle analysing interferometer has been devised for the measurement of double exposure laser speckle records, which displays simultaneously, side-by-side on a screen, the fringe pattern and an incoherent record of the speckel negative image, upon which the actual spot under interrogation is illuminated.

TL;DR: In this paper, the analysis and experimental procedure of a controlled temperature laser heat treating process are reported, with the ease of predicting working results and the capability of getting on-line process diagnostics for use in a highly automated industrial environment.

TL;DR: In this article, an astigmatic holographic optical element for processing by combined one-dimensional imaging and orthogonal Fourier transformation is described, and results on the numeric estimation of its properties and on the preliminary experiments for recording it are reported.

TL;DR: Development of an algorithm for the extraction of three-dimensional coordinates, using a point by point matching process, from a digital stereo pair of images is described.

TL;DR: In this article, an implementation of holographic moire inspection is demonstrated using one hologram to project the reference grating and a further hologram in order to produce moire patterns.

TL;DR: In this paper, the use of a relay system to transmit the pulsed laser output 20 m has been demonstrated in the laboratory, and the results showed that the output of the relay showed a resolution of 18l.p.

TL;DR: In this article, the output of a ruby laser oscillator in use at Marchwood Engineering Laboratories (MEL) consists of a random series of spikes contained in an envelope of about 800 μ. Due to the random nature of the output, the fringes are not readily quantifiable but show the characteristic bright zeroorder fringe of continuous wave time-averaged holography.

TL;DR: In this paper, a CO2 laser of over 5 kW for material processing with an unstable resonator of positive confocal configuration under high-pressure, sealed condition was developed and high quality beams with high extraction efficiency of the power were obtained.

TL;DR: In this paper, the application of electronic speckle pattern interferometry (ESPI) to the measurement of dynamic bulk modulus of elastomers is discussed, which is achieved by direct measurement of the volume contraction of submerged specimens subjected to sinusoidal pressure changes.

TL;DR: The development and use of a stereo-TV system to observe, record and measure spatial coordinates is described and a new approach to spatial coordinates measurement is proposed.