Showing papers on "Ruby laser published in 1968"
TL;DR: The theoretical capability, design considerations, and experimental testing of a pulsed ruby laser absorptivity spectrophone and a cw CO(2) laser absorberphone are described.
Abstract: A spectrophone measures absorptivity by sensing thermal expansion in a confined sample gas. Laser source excitation provides sufficient radiation to measure precisely very weak absorptivities at laser wavelengths. This paper describes the theoretical capability, design considerations, and experimental testing of a pulsed ruby laser absorptivity spectrophone and a cw CO2 laser absorptivity spectrophone. A spectrum of the water vapor line at 6943.8 A was obtained. The peak absorptivity was 3 × 10−6 cm−1. In the vicinity of 9.6 μ, absorptivities of CO2−N2 mixtures were measured down to 1.2 × 10−7cm−1.
170 citations
TL;DR: In this paper, a 30MW Q-switched ruby laser was focused into water, and the resulting spark revealed a blackbody-like spectrum with a temperature of 15 000°K.
Abstract: Measurements have been taken of the radiative flux density, the spectrum, and the temporal behavior of laser induced underwater sparks. When a 30‐MW Q‐switched ruby laser was focused into water, the resulting spark revealed a blackbody‐like spectrum with a temperature of 15 000°K. The spark was delayed in time by 15 nsec with respect to the laser pulse and had a temporal behavior very similar to the laser pulse producing it.
116 citations
TL;DR: In this paper, the image information at 1.6 μ has been converted to the green by mixing it with highly collimated ruby laser radiation in lithium niobate and about 50 lines resolution was achieved, limited only by the laser beam quality.
Abstract: Image information at 1.6 μ has been converted to the green by mixing it with highly collimated ruby laser radiation in lithium niobate. About 50 lines resolution has been achieved, limited only by the laser beam quality. A tenfold increase on this should be attainable with a single transverse mode laser.
114 citations
TL;DR: In this paper, the authors describe a spectroscopic study of the plasma produced when a giant pulse ruby laser of 5 J energy and 17 ns duration is focused into a 0.3 mm diameter spot on a polyethylene target in vacuum.
Abstract: This paper describes a spectroscopic study of the plasma produced when a giant pulse ruby laser of 5 J energy and 17 ns duration is focused into a 0.3 mm diameter spot on a polyethylene target in vacuum. Quantitative measurements of spectral intensities in the range from 20 Angstrom to 6000 Angstrom have yielded estimates of the electron and ion densities, the electron temperature and the streaming velocities of the ions. From these results it is estimated that the electron temperature, the ionization energy, the energy lost by radiation and the energy of recoil of the target account for only about 10% of the incident laser energy. The ion kinetic energy accounts for 70% of the incident energy with an experimental uncertainty of ± 70%. It is calculated that there are about 1016 ions produced by the laser beam striking the target. It is shown that the electrons contained in the plasma expanding away from the target cool adiabatically. In the course of the work there have been identified several new lines hitherto unclassified.
107 citations
TL;DR: In this article, Rayleigh scattering from atoms and molecules in the gaseous state at 1-atm pressure was measured using a Q-switched ruby laser of 8MW average power and care in minimizing spurious light.
Abstract: Measurements of Rayleigh scattering from atoms and molecules in the gaseous state at 1-atm pressure are described. The use of a Q-switched ruby laser of 8-MW average power and care in minimizing spurious light permitted the determination of very small depolarizations. No depolarization could be detected in the scattering from argon and helium. However, finite depolarization ratios ρν (for vertically polarized incident light) were measured for xenon and methane: 1.55(±0.25) × 10−4 and 1.27 (±0.23) × 10−4, respectively. Departures from ideal-gas behavior provide the most plausible explanation for these findings.Depolarization ratios were also measured in hydrogen, deuterium, nitrogen, and nitrous oxide, and were found to be lower than generally accepted values. Measured differential-scattering cross sections at 60° for He, Ar, Xe, CH4, H2, D2, N2, and N2O were within experimental error of values calculated from known indices of refraction. The angular dependence of Rayleigh scattering in N2 as a function of the polarization states of both incident and scattered radiation was studied from 30° to 150°, and was found to be in agreement with theory.
98 citations
TL;DR: In this paper, a Q-switched ruby laser is used to generate surface elastic waves by transient surface heating of piezoelectric and non-piezoeelastic solids.
Abstract: The generation of surface elastic waves by the transient surface heating of piezoelectric and nonpiezoelectric solids is described. A Q‐switched ruby laser produces the surface heating; the frequencies of the resultant surface waves are Fourier components of the laser waveform. The use of a spatially periodic illumination is shown to increase the effectiveness of generation at a selected frequency. This method of generating surface waves appears suitable for microwave frequency operation as well as operation at high wave amplitudes at low frequencies.
95 citations
TL;DR: Stimulated emission from 19 polymethine dyes pumped by a Q-switched ruby laser is reported in this paper. But the results are limited to the whole wavelength range from 710 mμ to 1060 mμ.
Abstract: Stimulated emission from 19 polymethine dyes pumped by a Q‐switched ruby laser is reported in this Letter. High power laser emission (>1 MW) has been obtained over the whole wavelength range from 710 mμ to 1060 mμ.
83 citations
TL;DR: In this article, the two-photon fluorescence (TPF) technique for the display of picosecond pulses is analyzed, and it is shown that TPF displays resembling those of the pulses from mode-locked lasers, but having reduced contrast, are produced by lasers in which mode locking is incomplete or absent.
Abstract: The two‐photon fluorescence (TPF) technique for the display of picosecond pulses is analyzed. It is shown that TPF displays resembling those of picosecond pulses from mode‐locked lasers, but having reduced contrast, are produced by lasers in which mode locking is incomplete or absent. We report here new TPF experiments which provide further evidence for picosecond pulse output of dye Q‐switched Nd:glass lasers. In addition, TPF observations with a single‐mode ruby laser are found to give contrast ratios in agreement with the general theory.
80 citations
TL;DR: In this paper, it was shown that self-focusing of the beam from a singlemode ruby laser may initiate laser-induced breakdown in filaments or points having a diameter of 5 \ensuremath{\mu} or less.
Abstract: Sparks produced by focusing the beam from a single-mode ruby laser have been investigated, and photographs of radiation scattered at 90\ifmmode^\circ\else\textdegree\fi{} to the incident beam show that breakdown occurs in filaments or points having a diameter of 5 \ensuremath{\mu} or less Intense pulses of coherent radiation scattered in the forward direction have also been observed, and the measured divergence of this light indicates the presence of self-focused regions having a diameter of \ensuremath{\sim}17 \ensuremath{\mu} These observations support the hypothesis that self-focusing of the beam may initiate laser-induced breakdown
70 citations
TL;DR: In this paper, a synthetic singlecrystal proustite pumped with collimated pulsed ruby laser radiation was used to convert 10.6 μm radiation to the visible.
Abstract: Synthetic single‐crystal proustite pumped with collimated pulsed ruby laser radiation has been used to convert 10.6 μm radiation to the visible. Measured values of photon conversion efficiency (Ns/Nir = 1.4 × 10−6) and phase‐matched bandwidth (540 A at 10.6 μm) are in good agreement with theory.
64 citations
TL;DR: In this article, a simple theoretical model taking this mechanism into account is proposed, and calculated curves for the outer radius variations of the shock front fit closely the experimental results, showing that the reinforced argon lines when moving off the Be target surface are probably due to a shock wave driven by the Be plasma acting as a piston.
Abstract: Shock waves in argon and in air have been observed when focusing a 0.8 J, 40 nsec, Q‐switched ruby laser beam onto a beryllium target in the presence of gas at various pressures ranging fron 2×10−1 to 3 Torr. High‐speed streak and framing camera as well as a prism spectrograph have been used as diagnostic tools. Space‐resolved spectra show, besides an intense continuum, Stark‐broadened lines from Be I and Be II. The reinforced argon lines when moving off the Be target surface are probably due to a shock wave driven by the Be plasma acting as a piston. A simple theoretical model taking this mechanism into account is proposed. Calculated curves for the outer radius variations of the shock front fit closely the experimental results.
TL;DR: In this article, an efficient room-temperature optical parametric oscillation was obtained using a single-mode, giant-pulse ruby laser to directly pump a crystal of LiNbO3 placed in an optical cavity resonant at both the signal and idler wavelengths and also in a cavity resonating at only the signal wavelength.
Abstract: Efficient room‐temperature optical parametric oscillation was obtained using a single‐mode, giant‐pulse ruby laser to directly pump a crystal of LiNbO3 placed in an optical cavity resonant at both the signal and idler wavelengths and also in a cavity resonant at only the signal wavelength. For the doubly resonant oscillator, 22% of the pump power was converted into signal power; for the singly resonant oscillator, conversion was 6%. The behavior of both oscillators was reproducible. Several features of the oscillator dynamics are discussed.
TL;DR: In this article, a 1.1′-diethyl-gl-nitro-4.4''-dicarbocyanine-tetrafluoro-borate dye laser with a 150 MW mode-locked ruby laser of the same transit time was used.
TL;DR: The minimum obtainable pulse duration for a mode-locked ruby laser is the reciprocal linewidth, which amounts to approximately 2 ps as mentioned in this paper, and the present correspondence describes a system achieving this limit.
Abstract: The minimum obtainable pulse duration for a mode-locked ruby laser is the reciprocal linewidth, which amounts to approximately 2 ps. The present correspondence describes a system achieving this limit.
TL;DR: In this article, a temperature jump apparatus for relaxation studies in electrolytic solutions has been developed with laser heating and conductivity readout, which is suitable for quantitative studies of relaxation times in the range 10−1 to 3×10−6 sec.
Abstract: Temperature‐jump apparatus for relaxation studies in electrolytic solutions has been developed with laser heating and conductivity readout. The apparatus is suitable for quantitative studies of relaxation times in the range 10−1 to 3×10−6 sec. With a ruby laser, an appropriate solute must be added to aqueous solutions lacking a colored solute to adjust the optical density of the solution to an appropriate value. With a neodymium laser, the intrinsic absorption of water in aqueous solutions is adequate.
TL;DR: In this paper, two short-lived new absorption hands and an anomalous blue fluorescence have been observed in cryptocyanine solutions excited by light from a giant-pulse ruby laser.
TL;DR: In this paper, a very rapid, spectroscopic recording technique with the aid of which photographic absorption spectra of transient intermediates with lifetimes in the nanosecond time range can be obtained.
Abstract: We have developed a new, very rapid, spectroscopic recording technique with the aid of which photographic absorption spectra of transient intermediates with lifetimes in the nanosecond time range can be obtained. The technique is a hundred times faster than present flash spectrographic instrumentation and provides time-resolved absorption spectra over a wide spectral range in a single experiment. Frequency-doubling is used to obtain both a 347 nm laser pulse suitable for excitation and a 694 nm laser pulse from a single Q -switched ruby laser pulse. The 694 nm pulse is converted into a continuum for absorption spectroscopy by bringing it to a sharp focus in a suitable gas, so as to cause a laser-induced breakdown spark. The excitation pulse has a duration of 30 ns. The duration of the continuum pulse varies with the gas used. In 1 atm of oxygen it has a duration of 30 ns, is synchronized to within 10 ns with the excitation pulse and has an intensity adequate for single-shot flash spectroscopy. The laser-induced spark in 1 atm of xenon has a duration of several μs and provides an excellent background continuum, of essentially constant intensity, for kinetic spectroscopy over periods up to 1 μs, using an image-converter camera to provide time resolution. We have applied the laser photolysis technique to observing, for the first time, absorption spectra arising from the lowest excited singlet states of several aromatic hydrocarbons. The time-resolved spectra obtained show the decay of the new excited singlet absorption bands and the concomitant build-up of triplet-triplet absorption bands during the first microsecond following light absorption, thus depicting graphically the non-radiative process of intersystem crossing from the lowest excited singlet state to the triplet manifold. The new bands also serve to locate the energies of higher excited singlet levels which, in many cases, are inaccessible from the ground state. The new technique should find wide application to solid, liquid and gaseous systems and should contribute to the understanding of photochemical primary processes in the time range 10 -9 to 10 -6 s. Eventual extension of the technique to the 10 -12 s range appears possible by using mode-locked lasers.
TL;DR: In this paper, the output from a Q-switched ruby laser was focused into a H2 cell and converted into pulses with halfwidths of 3 × 10−10 sec at 9755 A.
Abstract: Narrow pulses have been generated in a reverse‐pumped Raman laser containing H2. The output from a Q‐switched ruby laser was focused into a H2 cell and converted into pulses with halfwidths of 3 × 10−10 sec at 9755 A.
TL;DR: The two-photon fluorescence technique has been used to examine, on a picosecond time scale, the output of a long-pulse (non-Q-switched) Nd:glass laser.
Abstract: The two‐photon fluorescence technique has been used to examine, on a picosecond time scale, the output of a long‐pulse (non‐Q‐switched) Nd:glass laser. The well‐known ``spikes,'' about 200 nsec wide, are found, in many cases, to consist of a large number of ultrashort pulses, about 3 psec in duration. In a non‐Q‐switched ruby laser, pulses about 15 psec in duration have been seen.
TL;DR: The principle that laser frequencies which are appropriately matched to the absorption characteristics of target molecules can selectively inhibit specific molecular components in intact cells, if a controlled energy density range is used is illustrated.
Abstract: A frequency of 5300 A, derived from a frequency-doubled Q-switched neodymium laser was observed to produce progressive injury and death of cells from a culture of newborn rat cerebellum A subsequent observation that the green laser frequency (but not 6943 A of the same intensity from a Q-switched ruby laser) could reduce the rate of oxygen consumption of rat brain cell suspensions suggested that the cytochromes may serve as chromophores This hypothesis was confirmed by a demonstration that cytochromes c+c1 failed to act as hydrogen acceptors following 10 impacts of 1 Mw/cm2 each of the green laser frequency and cytochromes a+a3 showed a similar response when a brain cell suspension was irradiated (200 kw) with frequencies of 6096 and 6013 A These data illustrate the principle that laser frequencies which are appropriately matched to the absorption characteristics of target molecules can selectively inhibit specific molecular components in intact cells, if a controlled energy density range is used
TL;DR: In this paper, a gas phase photochemical addition of bromine to olefin molecules has been studied by inducing the reaction with monochromatic light near 6940 A from a pulsed, tunable ruby laser.
Abstract: Gas‐phase photochemical addition of bromine to olefin molecules has been studied by inducing the reaction with monochromatic light near 6940 A from a pulsed, tunable ruby laser. All previous photochemical reactions of bromine were induced with light at wavelengths shorter than 6800 A, and were found to proceed by means of free radical chains. The Br atoms initiating these chains are produced by direct dissociation of Br2 molecules upon absorption of light in the continuum. The present investigation shows that free‐radical chains are responsible for the reaction at 6940 A, also. However, direct dissociation at this wavelength is found to be negligible, and the Br2 molecules are excited to individual bound levels 500 to 800 800 cm− 1 below the dissociation energy. Kinetic and isotopic evidence shows that the additional energy is furnished by subsequent collisions, so that about 1% of the excited Br2 molecules become dissociated and can initiate the reaction. The remaining excited Br2 molecules relax by collisions to the ground state at a rate somewhat higher than the gas–kinetic‐collision rate.
TL;DR: Reflectivity enhancement of singlecrystal silicon, germanium, gallium arsenide, indium antimonide and polycrystalline boron and cadmium selenide was observed by irradiating the semiconductor with the output of a Q•switched ruby laser with pulses of 30 and 10 nsec as discussed by the authors.
Abstract: Reflectivity enhancement of single‐crystal silicon, germanium, gallium arsenide, and indium antimonide and polycrystalline boron and cadmium selenide was observed. The reflectivity variations were produced by irradiating the semiconductor with the output of a Q‐switched ruby laser (6943 A) with pulses of 30 and 10 nsec. The reflectivity variations were monitored with a pulsed argon‐ion laser (mainly 4880 and 5145 A). The effect of surface damage at high power levels produced an irreversible reflectivity decrease. Polished samples of molybdenum and tungsten, when irradiated by the Q‐switched ruby‐laser light, exhibited irreversible decreases in reflectivity due to surface damage and reversible variations, which were attributed to elastic deformation. Reflectivity enhancement of semiconductors was attributed to the formation on the semiconductor surface of a liquid film with metallic properties.
01 Jan 1968
TL;DR: In this article, the authors reviewed the results of an investigation of the characteristics in spike and bistable regimes of semiconductor lasers and proposed a general theory describing the dynamic processes in lasers.
Abstract: The generation of picosecond pulses by means of semiconductor lasers is reviewed, citing results of an investigation of the characteristics in spike and bistable regimes. Self-synchroni- zation of axial modes in a laser with an external mirror is also discussed. OTH theoretical and experimental investigations of the dynamics of different types of lasers were carried out after the spike structure in ruby laser radiation was observed (l). The study of dynamic processes leads to a number of effective methods for controlling the laser output. Various methods of &-switched modula- tion, lasers with nonlinear amplifiers for obtaining the short powerful light pulses, and lasers based on space and time synchronization of modes to obtain ultrashort pulses or single-mode outputs were developed; also proposed were methods of spike synchronization, etc. The studies included the kinetic processes in solid-state and gas lasers, the spike structure of giant pulses, and so on. Despite the great number of theoretical and experi- mental works there does not exist now a general theory describing the dynamic processes in lasers. This seems to
TL;DR: In this paper, the interaction of intense laser beams against single charged particles was investigated to determine the possibility of acceleration by surface evaporation, and the results agreed with momentum conservation involving vaporization of a fraction of the particle material.
Abstract: The interaction of intense laser beams against single charged particles was investigated to determine the possibility of acceleration by surface evaporation. Aluminum particles of 25 μ diam, freely suspended in a time‐varying electric field possessing focusing properties, were located within the focal spot (100 μ diam) of the normal output of a ruby laser. The individual laser spikes contribute to the stepwise acceleration of the particle and serve simultaneously for stroboscopic observation of the trajectory. With power densities of 106 W/cm2 and beam energies of a fraction of a joule, the recoil pressure due to the vaporization of the material produced directed velocities of 2 · 104 cm/sec. The present results agree with momentum conservation involving vaporization of a fraction of the particle material.
TL;DR: In this article, the properties of 1, 1' diethyl-γ-cyano-2, 2'-di-carbocyanine-tetrafluoroborate (DTCDCT) and 1.1'diethylγ-nitro-4, 4'di- carbocyaninesine-to-fluoric acid (DTNDCT) lasers have been investigated.
Abstract: The properties of 1, 1' diethyl-γ-cyano-2,2'-di-carbocyanine-tetrafluoroborate (DTCDCT)and 1, 1'-diethyl-γ-nitro- 4, 4'-di-carbocyanine-tetrafluoroborate (DTNDCT) lasers have been investigated. High-efficiency (25 percent) spectral narrowing of the normal 150-A-wide, 2-MW output of DTCDCT (around λ 7600 A) to 150 MW peak power) produces a train of 100 percent modulated mode-locked dye laser pulses whose risetimes ( 75 \times 10^{-3} cm-1of the λ 7699-A resonance line was detected for a ruby laser perturbing field of power density ∼ 30 MW/cm-2.
TL;DR: In this article, mode locking and ultrashort pulses have been produced in a giant-pulse ruby laser with heated nitrobenzene (T > 110°C) or α-chloronaphthalene inside the optical resonator.
Abstract: Mode locking and ultrashort pulses have been produced in a giant‐pulse ruby laser with heated nitrobenzene (T > 110°C) or α‐chloronaphthalene (T > 62°C) inside the optical resonator. 10−11‐sec pulses were observed with the two‐photon fluorescence technique.
TL;DR: Ruby lasers with power outputs of 230 and 800 m j caused no detectable lesions in the transparent media of the eye but produced marked changes in the iris of pigmented animals.
TL;DR: Mean kinetic energies and abundances of ionic species from plasmas of Al, Cu, and Au produced by focused Q-switched ruby laser light have been measured as discussed by the authors.
Abstract: Mean kinetic energies and abundances of ionic species from plasmas of Al, Cu, and Au produced by focused Q-switched ruby laser light have been measured. Electrostatic and time-of-flight methods are...