Showing papers in "Optics and Laser Technology in 1985"
101 citations
26 citations
TL;DR: A tube peeper that can view the whole panoramic field simultaneously has been devised in this paper, which is simpler to manufacture than conventional ones, and has the potential for miniaturization.
Abstract: In conventional endoscopy the imaging device has to rotated to produce a full 360° image. A new ‘tube peeper’ has been devised that can view the whole panoramic field simultaneously. The image produced has flat cylinder perspective rather than the familiar central convergence perspective. The device is simpler to manufacture than conventional ones, and has the potential for miniaturization
24 citations
TL;DR: In this paper, two methods of identifying fringe positions in speckle patterns were proposed, one using local directional averaging to track fringes, while the second using standard image processing techniques to connect the patterns into a form where the fringes can be identified.
Abstract: This paper two methods of identifying fringe positions in speckle patterns. The first uses local directional averaging to track fringes, while the second uses standard image processing techniques to connect the patterns into a form where the fringes can be identified.
17 citations
TL;DR: In this article, the light intensity diffracted from superimposed dual transmission gratings is sensitive to their relative lateral displacement but is also affected by changes in the air gap between them.
Abstract: The light intensity diffracted from superimposed dual transmission gratings is sensitive to their relative lateral displacement but is also affected by changes in the air gap between them. Averaging the diffracted light intensities obtained in the gap range of a Fourier image distance, the resultant intensity was almost independent of the gap between the two gratings and had a period of half the pitch of the grating for the lateral displacement. This method can be used for a linear encoder in precision machining.
16 citations
15 citations
TL;DR: In this article, real-time non-destructive testing of phase and transparent objects using degenerate four-wave mixing with photorefractive BGO crystals is described, and quantitative results of thickness variations of phase objects such as a thin optical wedge and a thin BGO crystal are also given.
Abstract: Real-time non-destructive testing of phase and transparent objects using degenerate four-wave mixing with photorefractive BGO crystals is described. Some quantitative results of thickness variations of phase objects such as a thin optical wedge and a thin BGO crystal are also given.
13 citations
TL;DR: In this article, an atmospheric gas monitor with a PbSnTe diode laser has been developed and the open, 1 m optical path in a single-folded configuration enables local and non-contact measurement in a portable instrument.
Abstract: An atmospheric gas monitor with a PbSnTe diode laser has been developed. The open, 1 m optical path in a single-folded configuration enables local and non-contact measurement in a portable instrument. The accuracy is dependent on optical noise and a technique in diode-current modulation was effective in suppressing it. Analysis of the system noise based on the experimental data was made and a 10 ms interval was sufficient to attain an accuracy of 3 ppm for methane. Field measurements were made and a rapid fluctuation in the density of atmospheric methane density was recorded.
13 citations
12 citations
TL;DR: In this article, a device for the monitoring of blood glucose levels is investigated, which measures the sugar concentration using the effect of the glucose on the optical refractive index, as most of the internal rays are incident at the fibre surface at an angle less than the critical angle.
Abstract: A device for the monitoring of blood glucose levels is investigated. It measures the sugar concentration using the effect of the glucose on the optical refractive index. Light is transmitted along an optical fibre, and, as most of the internal rays are incident at the fibre surface at an angle less than the critical angle, the refractive index of the surrounding liquid can be calculated. The device can measure glucose concentrations with a sensitivity of better than 0.1%.
12 citations
TL;DR: An optical system used for two-frame, high-speed photography of shadow and interference patterns is described as is a system for synchronizing ruby lasers to provide the necessary highly stable operation of electro-optical shutters as mentioned in this paper.
Abstract: An optical system used for two-frame, high-speed photography of shadow and interference patterns is described as is a system for synchronizing ruby lasers to provide the necessary highly stable operation of electro-optical shutters. Experimental data are presented relating to the interaction of a water drop with a rapidly moving sphere.
TL;DR: In this paper, it was shown that using suitably coated mirrors, it is possible to obtain far red lines from the Kr+ laser at 752.5 and 799.3 nm.
Abstract: The two continuous wave lasers normally used for Raman spectroscopy are the argon and krypton ion lasers. These routinely provide step tuning between 459.9 and 676.4 nm. However, it is possible, using suitably coated mirrors, to obtain far red lines from the Kr+ laser at 752.5 and 799.3 nm.
This additional capability offers advantages for Raman spectroscopy in the areas of fluorescence rejection, sample decomposition and resonance Raman spectroscopy.
TL;DR: In this paper, a theoretical analysis has been carried out to evaluate the power handling capability of hollow waveguides for CO 2 laser light, and it has been shown that hollow waveguide can transmit much higher powers than conventional metallic waveguide.
Abstract: A theoretical analysis has been carried out to evaluate the power handling capability of hollow waveguides for CO 2 laser light. Dielectric-coated metallic waveguides are shown to transmit much higher powers than conventional metallic waveguides.
TL;DR: In this article, a new method has been developed for fabricating germanium-coated, metallic, hollow waveguides by an electro-deposition technique, and preliminary experiments have been conducted to obtain cathode current efficiency and conditions for a uniformly deposited Germanium layer for plane metallic plates.
Abstract: A new, efficient method has been developed for fabricating germanium-coated, metallic, hollow waveguides by an electro-deposition technique. Preliminary experiments have been conducted to obtain cathode current efficiency and conditions for a uniformly deposited germanium layer for plane metallic plates. The experiments have also shown that a thin germanium layer can be deposited inside metallic pipes with strong adhesion.
TL;DR: In this paper, a qualitative but generalized description of the kinetics of changes in the physico-chemical parameters of living material in interaction with optical radiation is given, and it is shown that depending upon the degree of homoeostasis, which is a function of the evolutionary stage of the living material, the result of the interaction may vary considerably.
Abstract: Based on the difference between non-living and living material which manifests itself in the fact that the latter has not only a ‘physico-chemical’ but also a ‘biological’ character, that is, it is a regulatory homoeostatic system, a qualitative but generalized description of the kinetics of changes in the physico-chemical parameters of living material in interaction with optical radiation is given. It is shown that depending upon the degree of homoeostasis, which is a function of the evolutionary stage of the living material, the result of the interaction may vary considerably. Examples backing up the model restrict themselves to the visible spectrum of optical radiation; however, the model is capable of describing the effects of ultra-violet, infra-red or microwaves on living material.
TL;DR: In this paper, a method based on the diffraction of light is presented for producing binary diffraction gratings with arbitrary opening ratios in both x and y directions, and it is shown that using two master gratings of the Ronchi type and utilizing the results of the double diffraction system, it is possible to produce binary gratings having an arbitrary opening ratio.
Abstract: In this paper, a method — based on the diffraction of light — for producing binary diffraction gratings is presented It is shown that using two master gratings of the Ronchi type and utilizing the results of the double diffraction system it is possible to produce binary gratings with an arbitrary opening ratio The results have been extended for a two-dimensional case and it is shown that producing binary grid gratings with arbitrary opening ratios in both x and y directions is also possible
TL;DR: In this article, a red (633 nm) laser beam was passed through the platelet pack, and the scatter measured, and live platelets scattered the beam differently from dead ones, owing to their different shape.
Abstract: An experimental study has been carried out to test the feasibility of optically assessing the viability of stored blood platelets. A red (633 nm) laser beam was passed through the platelet pack, and the scatter measured. Live platelets scattered the beam differently from dead ones, owing to their different shape. The results compared favourably with those from established in vitro tests of platelet viability.
TL;DR: In this article, an interferometer with holographic optics, which has a large visualization field, is described, and correction for aberration of the interferometers is obtained, and non-aberration interferograms of the heat flows are made.
Abstract: An interferometer with holographic optics, which has a large visualization field, is described. Correction for aberration of the interferometer is obtained, and non-aberration interferograms of the heat flows are made. The interferometer with a 100 mm visualization field can be used for the study of transparent media.
TL;DR: In this article, the authors used the differential absorption of a narrowband tunable ultra-violet laser for integrated measurements of tropospheric trace gas concentrations over a path length of 12.8 km, at near ground level.
Abstract: A method is described which uses the differential absorption of a narrow-band tunable ultra-violet laser for integrated measurements of tropospheric trace gas concentrations over a path length of 12.8 km, at near ground level. A XeCl excimer laser serves as a reference beam to compensate for turbulence-induced intensity losses. After suitable statistical averaging the method is capable of detecting differential absorptions as low as 10-4, enabling the simultaneous detection of SO2, CH2O and of OH radicals around 308 nm.
TL;DR: In this article, the inherent accuracies of various techniques for determining the optical constants of thin films have been assessed by computing the errors produced in n and k by known experimental errors in the optical functions being measured.
Abstract: The inherent accuracies of various techniques for determining the optical constants of thin films have been assessed by computing the errors produced in n and k by known experimental errors in the optical functions being measured. The results are presented as arrays of error parallelograms in the n–k plane covering d /λ from 0.001 to 0.20 and θ from 5° to 85°. The largest regions of accuracy, in the form of annular quadrants, were obtained using the mixed photometric and polarimetric functions at small angles of incidence. Ellipsometry gives similar results at large angles of incidence but for photometry and for polarimetry the accurate regions were in the form of two lobes. The effects of errors in x and θ were also considered.
TL;DR: In this article, a simple technique for the alignment of a ring resonator is presented, where the positional and the directional alignments are obtained by the movements of independent mirrors, and the effects of alignment inaccuracies on the performance of ring resonators are discussed.
Abstract: A simple technique for the alignment of a ring resonator is presented. The positional and the directional alignments are obtained by the movements of independent mirrors. The effects of alignment inaccuracies on the performance of a ring resonator are discussed.
TL;DR: In this paper, a passive splitter array is described which allows time-resolved plasma diagnostic measurements to be performed on a single shot basis, and the advantage of this stacker is that it has high efficiency, is simple, easy to adjust, and can be inserted into an optical beam path without disturbance to alignment.
Abstract: A passive splitter array is described which allows time-resolved plasma diagnostic measurements to be performed on a single shot basis. The advantage of this stacker is that it has high efficiency, is simple, easy to adjust, and can be inserted into an optical beam path without disturbance to alignment.
TL;DR: An experimental study to synthesize holographically two-dimensional projections of serial sections at various depths into three-dimensional images is described, and the advantages and limitations of this method are discussed.
Abstract: An experimental study to synthesize holographically two-dimensional projections of serial sections at various depths into three-dimensional images is described. The effects caused by the position, size and resolution of virtual images during reconstruction are analysed, and the advantages and limitations of this method are discussed. An application of this experimental method — the three-dimensional reconstruction of serial sections of a newt embryo — is presented.
TL;DR: In this paper, the first time it has been possible to laser weld copper sheets up to 3 mm thick with a 2 kW cw CO 2 laser was presented, and the main questions arising from the process were indicated.
Abstract: For the first time it has been possible to laser weld copper sheets up to 3 mm thick with a 2 kW cw CO 2 laser. The main questions arising from the process are indicated.
TL;DR: In this article, an experimental fiber-optic cable with a base of polycrystalline KRS-5 (TiBrl) infra-red fiber, which can be used in medical and technological purposes, is given.
Abstract: A description of an experimental fibre-optic cable with a base of polycrystalline KRS—5 (TiBrl) infra-red fibre, which can be used in medical and technological purposes, is given. The length of the cable is 1.2 m, the diameter of the fibre is 1 mm, and the total diameter of the cable is 8 mm. The transmission of 7 W (CO laser) and 15 W (CO 2 laser) continuous radiation for a few hours is realized with the cable.
TL;DR: In this article, two methods of sharpening the interference fringes in lateral shear interferometry are described, one method exploits the non-linearity of the recording process, while the other is based on the characteristics of the multiply-recorded diffractive element.
Abstract: Two methods of sharpening the interference fringes in lateral shear interferometry are described. One method exploits the non-linearity of the recording process, while the other is based on the characteristics of the multiply-recorded diffractive element. Both methods can be combined to obtain further fringe sharpening in the higher orders.
TL;DR: In this article, a dc micromotor operating in a closed loop positioning servo was used to tune a CO2 laser wavelength with microcomputer-controlled diffraction grating positioning.
Abstract: A CO2 laser wavelength tuning system with microcomputer-controlled diffraction grating positioning is reported. The system employs a dc micromotor operating in a closed loop positioning servo and is characterized by simplicity of hardware. Fast wavelength tuning over a broad spectral range is achieved with the variable positioning speed technique. System performance is evaluated in conjunction with a TEA CO2 laser.