Showing papers on "Ruby laser published in 1979"
TL;DR: In this paper, the transition to single crystal of ion-implanted amorphous Si and Ge layers is described in terms of a liquid phase epitaxy occurring during pulsing-laser irradiation.
Abstract: The transition to single crystal of ion‐implanted amorphous Si and Ge layers is described in terms of a liquid‐phase epitaxy occurring during pulsing‐laser irradiation. A standard heat equations including laser light absorption was solved numerically to give the time evolution of temperature and melting as a function of the pulse energy density and its duration. The structure dependence of the absorption coefficient and the temperature dependence of the thermal conductivity were accounted for in the calculations. In this model the transition to single crystal occurs above a well‐defined threshold energy density at which the liquid layer wets the underlying single‐crystal substrate. Experiments were performed in ion‐implanted amorphous layers of thicknesses ranging between 500 and 9000 A. The energy densities of the Q‐switched ruby laser ranged between 0.2 and 3.5 J/cm2; time durations of 20 and 50 ns were used. The experimental data are in good agreement with the calculated values for the amorphous thickness–energy−density threshold. The model deals mainly with plausibility arguments and does not account for processes occuring in the near‐threshold region or below the melting temperature.
352 citations
TL;DR: A polarized light interferometer, suitable for the high-speed photography of microscopic objects in laser fusion experiments, is described, based on a Wollaston prism as beam splitter, with main advantages are its relative simplicity, the absence of alignment and stability problems, and the extended spectral range down to 0.18 mum wavelength.
Abstract: A polarized light interferometer, suitable for the high-speed photography of microscopic objects in laser fusion experiments, is described. Based on a Wollaston prism as beam splitter, its main advantages are its relative simplicity, the absence of alignment and stability problems, and the extended spectral range down to 0.18 mum wavelength. The interferometer has been successfully applied in CO(2) and neodymium laser plasma interaction studies with laser illumination at 0.694 mum (ruby laser) and 0.265 mum (4th harmonic of the Nd(3+) laser) wavelength.
121 citations
TL;DR: Comparisons are made between the water vapor DIAL measurements and data obtained from locally launched rawinsondes, and agreement was found to be within the uncertainty of the rawinsonde data to an altitude of 3 km.
Abstract: A ground-based differential absorption lidar (DIAL) system is described which has been developed for vertical range-resolved measurements of water vapor. The laser transmitter consists of a ruby-pumped dye laser, which is operated on a water vapor absorption line at 724.372 nm. Part of the ruby laser output is transmitted simultaneously with the dye laser output to determine atmospheric scattering and attenuation characteristics. The dye and ruby laser backscattered light is collected by a 0.5-m diam telescope, optically separated in the receiver package, and independently detected using photomultiplier tubes. Measurements of vertical water vapor concentration profiles using the DIAL system at night are discussed, and comparisons are made between the water vapor DIAL measurements and data obtained from locally launched rawinsondes. Agreement between these measurements was found to be within the uncertainty of the rawinsonde data to an altitude of 3 km. Theoretical simulations of this measurement were found to give reasonably accurate predictions of the random error of the DIAL measurements. Confidence in these calculations will permit the design of aircraft and Shuttle DIAL systems and experiments using simulation results as the basis for defining lidar system performance requirements.
120 citations
TL;DR: In this article, the boundary between a linear and a nonlinear medium should have a reflection coefficient which exhibits hysteresis as a function of optical intensity, and the first experimental evidence of this effect is presented.
Abstract: Under suitable conditions, the boundary between a linear and a nonlinear (Kerr effect) medium should have a reflection coefficient which exhibits hysteresis as a function of optical intensity. We present the first experimental evidence of this effect. Experiments were performed using ∼1‐ns ruby laser pulses incident on a glass‐CS2 boundary.
110 citations
TL;DR: In this paper, the temperature reached by silicon and cadmium telluride surface layers under high power density ruby laser pulsed illumination, is calculated by solving the time-dependent heat flow equation.
Abstract: By solving the time-dependent heat flow equation, the temperature reached by silicon and cadmium telluride surface layers under high power density ruby laser pulsed illumination, is calculated. The results are presented in directly useful figures allowing the determination of the surface temperature, its evolution towards the bulk as a function of time... In particular, it should be noticed that for a 25 ns half-power width, pulses of 0.8J/cm2 are sufficient to melt the top of an amorphous silicon layer, this value becomes noticeably lower for cadmium telluride.
88 citations
TL;DR: In this article, the effects of pulsed (Q•switched) ruby-laser annealing of arsenic and antimony-implanted silicon (1×1015 to ∼2×1016 cm−2) has been studied by Rutherford ion backscattering, TEM, and ion channeling.
Abstract: The effects of pulsed (Q‐switched) ruby‐laser annealing of arsenic‐ and antimony‐implanted silicon (1×1015 to ∼2×1016 cm−2) has been studied by Rutherford ion backscattering, TEM, and ion channeling. The laser pulses were of ∼50‐nsec time width and of 1.5–1.7 J/cm2 energy density. Analysis of the dopant profiles before and after annealing leads to the conclusion that the dopants diffuse under normal kinetics in a melted silicon layer over an average time interval of about 0.27‐μsec after the laser power has been absorbed. Recrystallization of the melt layer is by liquid‐phase epitaxial regrowth from the substrate. The recrystallized zone is found to be free of significant structural defects for all specimens except the very highest antimony doses, in which case some near‐surface (∼400 A) precipitation at dislocations is observed. Atom‐location measurements reveal that 98–99% of the retained dopant is in substitutional lattice sites even when the dopant concentration greatly exceeds the limit of solid solu...
85 citations
TL;DR: In this article, the anti-Stokes rotational Raman scattering from nitrogen gas at near atmospheric pressure and room temperature has been used to calibrate the intensity of ruby laser light Thomson scattered from a plasma in a transverse magnetohydrodynamic shock tube.
Abstract: Anti-Stokes rotational Raman scattering from nitrogen gas at near atmospheric pressure and room temperature has been used to calibrate the intensity of ruby laser light Thomson scattered from a plasma in a transverse magnetohydrodynamic shock tube. The main limit to the accuracy of this calibration method is the uncertainty in the available Raman cross section for nitrogen.
45 citations
TL;DR: In this paper, a pulsed-laser radiation was used to grow homoepitaxial p-n junctions in silicon, and perfect epitaxial layers with good electrical characteristics and controlled dopant profiles can be achieved.
Abstract: We have used pulsed‐laser radiation to grow homoepitaxial p‐n junctions in silicon. Doped amorphous silicon was deposited on (100) and (111) silicon substrates and annealed with a Q‐switched ruby laser. By this technique, perfect epitaxial layers with good electrical characteristics and controlled dopant profiles can be achieved. The technique can potentially be competitive with or replace ion implantation for many semiconductor‐device applications.
39 citations
TL;DR: In this article, a short-channel MOS FET was fabricated using Q-switched ruby laser irradiation on As-implanted sources and drains, and the thresholdvoltage-vs-channel length relation was improved as a result of the extremely limited lateral diffusion of implanted As atoms.
Abstract: Short‐channel MOS FET’s are successfully fabricated using Q‐switched ruby laser irradiation on As‐implanted sources and drains. Implantation and laser irradiation are both self‐aligned by the polysilicon gate electrodes. The threshold‐voltage–vs–channel‐length relation is improved as a result of the extremely limited lateral diffusion of implanted As atoms.
21 citations
TL;DR: In this paper, the implanted polysilicon films, about 0.6 μm thick, deposited on SiO2 grown on silicon substrates, were implanted with different doses of 11B, 31P, or 75As ions and laser annealed with a Q-switched Ndglass or ruby laser.
Abstract: Polysilicon films, about 0.6 μm thick, deposited on SiO2 grown on silicon substrates, were implanted with different doses of 11B, 31P, or 75As ions and laser annealed with a Q‐switched Nd‐glass or ruby laser. It was found that complete activation of the implanted dopant ions could be achieved with a pulse power density as low as 16 MW/cm2, that a two to three times reduction of resistivity could be achieved in implanted polysilicon films compared with samples thermally annealed, and that there were little or no redistributions of the implanted profiles.
20 citations
TL;DR: Drilling of extracted urinary stones was attempted using a continuous wave CO2 laser and a pulse ruby laser and stones were drilled easily by either laser beam.
Abstract: Disintegration of urinary calculi was attempted by the use of laser beam. As a first step, drilling of extracted urinary stones was attempted using a continuous wave CO2 laser and a pulse ruby laser. Stones were drilled easily by either laser beam. The power around 10 W of continuous CO2 laser beam was sufficient to drill through the stone.
TL;DR: Stimulated emission was observed when ZnTe, ZnSe, and CdS single crystals were exposed to two-photon excitation by a train of ruby laser picosecond pulses.
Abstract: Stimulated emission was observed when ZnTe, ZnSe, and CdS single crystals were exposed to two-photon excitation by a train of ruby laser picosecond pulses The lasing wavelengths for ZnTe, ZnSe, and CdS crystals were 530, 450, and 495 nm, respectively The angular divergence was 19–21° and the laser action occurred at peak exciting pulse intensities of around 1 GW/cm2
27 Jul 1979
TL;DR: In this paper, the dynamics of cavities produced in the liquid upon breakdown are investigated by high-speed photograph and holography, and a grating is used to film the motion of the cavities.
Abstract: Optical breakdown phenomena in liquids due to focused ruby laser light are investigated by high-speed photograph: and holography Special attention is given the dynamics of the cavities produced in the liquid upon breakdown as they can be expected to become a powerful research tool in cavitation physics To this end the production of threedimensional breakdown configurations would be desirable as well as their investigation by high-speed holographic means Both problems are presently under study To achieve multiple breakdown at preselected points in the liquid a grating - lens assembly and digital holograms in photore-sist are used To film the motion of the cavities high-speed holocinematographic methods are developed By now four to eight holograms can be taken at a rate of 10 to 20 kHz© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only
TL;DR: In this article, the role of laser parameters and gas flow rates was studied using a silver plate as target, and the accuracy of calibration based on microscopic measurement of the crater depth was investigated with laser parameters suitable for gradual evaporation of the layer.
TL;DR: In this paper, a thermal model was developed to predict the depth of melting and the recrystallization velocity of the defect free region in silicon with a Q-switched ruby laser.
Abstract: Defect annihilation has been observed in silicon as a result of laser annealing using a Q‐switched ruby laser. The threshold pulse energy density for defect annihilation was found to be 1 J/cm2 (pulse length ∼25 ns), and the depth of the defect‐free region was found to increase with increasing pulse energy. A thermal model was developed which predicts the depth of melting and the recrystallization velocity. The calculated depth of melting was found to be in good agreement with the experimentally determined depth of defect annihilation. The defect annihilation occurs as a direct result of the extremely high recrystallization velocities which are associated with laser annealing with short pulses.
Journal Article•
TL;DR: In this study, iridotomies in rhesus monkeys were produced with a single exposure to a Q-switched ruby laser pulse, showing evidence of a nonlinear laser-iris interaction.
Abstract: Laser iridotomies have been pursued as a means of performing anterior segments surgery as a virtually noninvasive procedure. An ideal single laser pulse technique has been elusive. In this study, iridotomies in rhesus monkeys were produced, with a single exposure to a Q-switched. ruby laser pulse. The iridotomy formation was accompanied by acoustic wave generation, bubble formation, and explosive tissue disruption, evidence of a nonlinear laser-iris interaction. The average energies at which these iridotomies were produced ranged between 18 and 48 mj, some of the lowest energies reported for a laser iridotomy. Corneal changes were observed both at the epithelium and at the endothelium in some, but not all, of the eyes exposed. The epithelial changes morphologically resembled, nonlinear damage reported for transparent solids. Damage to physical materials has been attributed to stimulated. Brillouin scattering, a mechanism that may also play a role at the cornea. Consideration of such phenomena should be a part of the clinical evaluation prior to exposure of a cornea to high-power laser pulses. Although the endothelial change was more difficult to analyze, a shock-wave effect could not be discounted.
TL;DR: In this paper, the threshold power density for laser-induced epitaxial recrystallization of 2100 A thick amorphous silicon layers, produced by implantation of As, Sb, Sn and Ga ions, depends on the type and dose of dopants used and that it is independent of these parameters for the 0.69 μm radiation of a single-pulse ruby laser.
Abstract: It is found that when uncoated GaAs samples are irradiated with a Q-switched ruby laser, the samples suffer substantial weight losses for laser cnergy densities > 0·3 J/cm2. These weight losses are believed to result from the vaporization of the samples during the period in which the surfaces are in a molten state. The incomplete electrical activation of implanted ions in GaAs after laser annealing can be accounted for by the weight-loss phenomenon.
TL;DR: In this paper, a 50MW 60 ns ruby laser was used to study the variation of plasma temperature with laser flux for a carbon and polyethylene plasma in a purely collisional regime.
Abstract: The experiments were conducted with a 50‐MW 60‐ns ruby laser to study the variation of plasma temperature with laser flux for a carbon and polyethylene plasma in a purely collisional regime. The plasma temperature showed a φ2/9 dependence on laser flux in the intensity regime 2×1010 to 5×1011 W/cm2. Results are discussed with reference to the scaling laws obtained by different workers in different flux regimes on the basis of collisional and noncollisional absorption.
TL;DR: The vibrational Green's function for diatomic molecules has been constructed numerically for the Morse potential as discussed by the authors, and the two-photon dissociation for H + 2 has been calculated around the ruby laser frequency, for which high intensity laser radiation is experimentally available.
TL;DR: When semi-insulating GaAs samples are coated with pyrolytically deposited Si3N4 layers and subsequently irradiated with a Q-switched ruby laser with energy densities > 0.3 J/cm2, it is found that a thin layer (0.1-0.25 μm) of the underlying GaAs substrates becomes n-type as discussed by the authors.
Abstract: When semi-insulating GaAs samples are coated with pyrolytically deposited Si3N4 layers and subsequently irradiated with a Q-switched ruby laser with energy densities > 0.3 J/cm2, it is found that a thin layer (0.1-0.25 μm) of the underlying GaAs substrates becomes n-type. This phenomenon may be the reason why, in previous work on laser annealing of donor implanted GaAs samples, the percentage electrical activity increased when samples were coated with Si3N4.
TL;DR: In this article, the photoluminescence properties of laser-annealed single-crystal GaAs were measured and a theoretical prediction of the temperature distribution at the end of the laser pulse was performed.
Abstract: We have measured the photoluminescence properties of laser‐annealed single‐crystal GaAs. The quantum efficiency of the band‐edge emission at liquid helium temperatures was increased by 3 orders of magnitude after a single 10−3‐s pulse of ruby laser light. This increase in radiative efficiency is thought to be due to dissociation of Si‐donor‐Ga‐vacancy complexes, which is expected to decrease nonradiative processes and possibly increase radiative centers. A theoretical prediction of the temperature distribution at the end of the laser pulse was performed.
TL;DR: Partially damaged self-ion implanted Si(100) has been irradiated by a ruby laser pulse (λ=0.69 μm, tp=15 ns) and TEM micrographs show the reordering of the implanted layer in the laser energy range 1.5-2.5 J/cm2.
Abstract: Partially damaged self‐ion implanted Si(100) has been irradiated by a ruby laser pulse (λ=0.69 μm, tp=15 ns). Channeling effect technique measurements and TEM micrographs show the reordering of the implanted layer in the laser energy range 1.5–2.5 J/cm2. No polycrystalline transition has been detected. Calculations in terms of local melting of the disordered zone explain the experimental data.
TL;DR: In this paper, the ground and excited-state absorption of cryptocyanine/methanol at 815, 685, 550, 430, and 310 nm is measured as a function of the photon flux density of a simultaneously exciting Q-switched ruby laser pulse.
TL;DR: In this article, a Q-switched ruby laser was used to heat-treat vapour phase-epitaxial (v.p.e.) GaAs and the characteristic A-centre, a deep trapping level at 0.83 eV, was removed using a laser pulse of energy density 0.3 J cm−2.
Abstract: A Q-switched ruby laser has been used to heat-treat vapourphase-epitaxial (v.p.e.) GaAs. The characteristic A-centre, a deep trapping level at 0.83 eV, is removed using a laser pulse of energy density 0.3 J cm−2. Trapping levels are observed using deep-level transient spectroscopy (d.l.t.s.).
TL;DR: In this article, the spectrum of the broad-band light generated by focusing picosecond laser light into a cell containing phosphoric acid was measured with an OMA and the dependence of the spectrum on the pumping energy was studied.
TL;DR: The J.I.P. T-II as discussed by the authors was the first to use the Thomson method of scattering ruby laser light in a tokamak apparatus, and the results were displayed graphically in terminals between each shot.
Abstract: Measurements of electron temperature and density in the J.I.P.P. T-II device ware made using the Thomson method of scattering ruby laser light. Of all the laser scattering systems ued in tokamak apparatus, the Thomon scattering system when applied to the J.I.P.P. T-II device has the brightest light collecting system ever obtained. The electron temperature could be measured without the viewing dump and light baffles by the use of the high quality filters. The scattered lights are processed by an on-line date-processing computer and the results are displayed graphically in terminals between each shot.
TL;DR: In this paper, a single pulse from a ruby laser is shown to cause significant regrowth in the amorphous region of indium-implanted silicon, and approximately 60% of implanted atoms occupied regular lattice positions in the crystal.
Abstract: A single pulse from a ruby laser is shown to cause significant regrowth in the amorphous region of indium-implanted silicon. RBS measurements demonstrated that compared to thermal annealing, there is no loss of indium atoms from (111) silicon substrates, and at the same time, approximately 60% of implanted atoms occupy regular lattice positions in the crystal. There has been noticeable redistribution of the indium atoms, causing maximum concentration at the surface.
TL;DR: In this article, the authors used OH-stabilized F2+ centers in LiF pumped by free-oscillation ruby laser radiation to obtain an atmospheric air absorption spectrum in the range 0.9-0.98μ.
Abstract: Laser action was achieved in OH-stabilized F2+ centers in LiF pumped by free-oscillation ruby laser radiation. The spectral range of the stimulated emission was 0.84–1.13μ. In a nonselective resonator, an atmospheric air absorption spectrum in the range 0.9–0.98μ was obtained by intracavity laser spectroscopy. The sensitivity was governed by the pump pulse duration of 1 μsec and was 3×10–5cm–1. Absorption spectra of C2H2, CH3OH, and CH4 were obtained in this spectral range. The results showed that lasers utilizing color centers in alkali halide crystals are potentially useful for intracavity laser spectroscopy.
TL;DR: In this article, the properties of the enhanced electron density fluctuations in a plasma jet are studied as a function of the laser intensities and frequencies by observing the spectra of ruby-laser radiation scattered by the density fluctuations.
Abstract: Enhanced electron-density fluctuations in a plasma jet are produced by the nonlinear interaction of the plasma with two pulsed dye-laser beams, one of which is of variable frequency. The properties of the enhanced fluctuations are studied as a function of the laser intensities and frequencies by observing the spectra of ruby-laser radiation scattered by the density fluctuations. The ruby laser also pumps the dye lasers. The dependence of the scattered signals on the laser intensities is well described by theory, but the response of the plasma to mixing forces of variable frequency is anomalous.