scispace - formally typeset
Search or ask a question

Showing papers on "Ruby laser published in 1967"


Journal ArticleDOI
C. Giuliano1, L. Hess1
TL;DR: In this article, a review of spectroscopic properties of complex molecules is presented and used to show that a simple two-level scheme is inadequate to describe the optical bleaching of dye molecules.
Abstract: A review of spectroscopic properties of complex molecules is presented and used to show that a simple two-level scheme is inadequate to describe the optical bleaching of dye molecules. Experimental data are reported for the transmission of intense ruby laser radiation by several types of dyes. Rate equation analyses are carried out using steady-state solutions and iterative computer solutions; calculated bleaching curves are compared with our data for cryptocyanine. On these bases, we show that, in general, the optical bleaching process involves the removal of ground-state molecules to other states having smaller absorption cross sections at the exciting frequency, and that recovery of absorption at this frequency is characterized by a complex relaxation mechanism.

199 citations


Journal ArticleDOI
TL;DR: In this article, the authors compared the stimulated emission spectra of two organic dyes, chloro-aluminum phthalocyanine (CAP) and 3,3′-diethylthiatricarbocyanines iodide (DTTC), using a giant-pulse ruby laser excitation.
Abstract: Stimulated emission spectra of two organic dyes, chloro-aluminum phthalocyanine (CAP) and 3,3′-diethylthiatricarbocyanine iodide (DTTC) are compared. Giant-pulse ruby laser excitation was used in both cases. An end pumping configuration employed with DTTC resulted in narrow beam divergences and high conversion efficiencies. For CAP, the oscillating transition is one which terminates on an excited vibrational level of the ground electronic state. For DTTC, stimulated emission at the lowest concentrations occurs at the peak of the Franck–Condon-shifted fluorescence band but moves to longer wavelengths as the concentration is increased. The transient behavior of the CAP laser, pumped in a transverse geometry, was observed and compared with computer solutions of the rate equations. Polarization measurements of the laser beams were also made. An analysis is given of requirements for achieving optimal pumping by means of flashlamps. ‡ [The paper concludes with an addendum reporting recent observations of stimulated emission from dye solutions lasing at wavelengths ranging from blue (4385 A) to orange (6000 A)].

188 citations


Journal ArticleDOI
TL;DR: In this article, the growth of the luminous plasma front during laser irradiation was in accordance with a prediction based on a radiatively supported detonation wave model in which a Gaussian pulse shape was used for the instantaneous energy addition.
Abstract: The plasma created by the output of a 2 to 10 J Q‐switched ruby laser focused into air, argon, helium and hydrogen at pressures from 15 to 1000 psi has been photographically recorded during and after the laser heating pulse. The growth of the luminous plasma front during laser irradiation was in accordance with a prediction based on a radiatively supported detonation‐wave model in which a Gaussian pulse shape was used for the instantaneous energy addition. With hydrogen at atmospheric pressure an appreciable fraction of the laser energy was transmitted. Consequently, the detonation‐wave model had to include only partial absorption of the incident laser beam. This was done by using the inverse bremsstrahlung absorption coefficient and a constant depth of energy addition. The shock wave created by this sudden energy addition was observed by using a Schlieren system. The growth of the shock wave was not in accordance with that predicted by spherical‐blast‐wave theory. The shock‐wave position from the initial point of breakdown varied as time from breakdown to the (0.20 ± 20%) power independent of gas species or operating condition.

80 citations


Journal ArticleDOI
TL;DR: A large amount of laser energy is delivered accurately to the target area and one is able to capitalize on the differential uptake of light energy by dark versus light materials.
Abstract: SURGICAL tattoo removal is generally unsatisfactory. 1 Total excision or partial excision in stages usually leaves a noticeable, wide scar. Complete excision and skin grafting not only scar the site of the tattoo but the skin graft donor site as well. Many patients accept the surgical treatment for tattoos only because the social stigma of the tattoo is of greater hindrance than the scarring. The laser is uniquely adapted for this surgical problem. Emitting a brief (8 to 10 nanosecond (nsec) Q-pulsed; 1.8 msec long pulse) narrow band (6,943 Angstroms) of high energy light (100 megawatt), the ruby laser beam, as any light, is absorbed more by dark substances than by light substances. A large amount of laser energy is delivered accurately to the target area and one is able to capitalize on the differential uptake of light energy by dark versus light materials. It can be done without

64 citations


Journal ArticleDOI
TL;DR: In this paper, the primary source was a nitrobenzene Raman•shifted ruby laser, and the secondary beam frequency was 58 cm−1 to the high energy side of νp.
Abstract: Stimulated electronic Raman scattering in potassium vapor is observed. The primary source was a nitrobenzene Raman‐shifted ruby laser. The secondary beam frequency occurs 58 cm−1 to the high energy side of νp.

49 citations


Journal ArticleDOI
TL;DR: Characteristics of the laser suggest its potential usefulness in otology, which enables us to predict to some extent which tissues will absorb and which will transmit the laser light beam.
Abstract: CERTAIN characteristics of the laser suggest its potential usefulness in otology. Foremost is the very small and discrete area that can be irradiated without affecting adjacent tissue. For example, the light produced by a laser can be so focused that it can damage a single large blood cell without evident injury to nearby cells. Since all of the light energy in the pulsed laser is emitted in a short time, the laser is a narrow beam of extremely high power. Another important feature is that the light generated by the laser is of a very narrow frequency band. This enables us to predict to some extent which tissues will absorb and which will transmit the laser light beam. A ruby laser, for instance, has a wave length of 0.649μ and falls into the visible spectrum whereas a neodymium laser has a wave length of 1.06μ and falls into the infrared

44 citations


Journal ArticleDOI
TL;DR: Results of the study indicated the potential use of laser energy as a cavity preparation instrument.
Abstract: Fifteen extracted human teeth were cut with focused laser energy from a ruby laser. Although cavity preparations with sharp line angles were not achieved, results of the study indicated the potential use of laser energy as a cavity preparation instrument.

43 citations


Journal ArticleDOI
TL;DR: In this paper, a combination of a Q-switched ruby laser and the stimulated Stokes radiation of a Raman scattering liquid, is used for excitation, which is shown to be more efficient than using a single laser.

37 citations


Journal ArticleDOI
07 Jul 1967-Science
TL;DR: The results have shown that selective excitation obtained with a tunable monochromatic laser is a useful technique for studying photochemical and energy transfer processes and a new phenomenon in the photochemistry of bromine was observed.
Abstract: Gaseous chemical reaction dynamics analyzed with monochromatic laser light-induced photocatalysis

36 citations


Journal ArticleDOI
TL;DR: In this article, an optical parametric oscillator was achieved in LiNbO3 in the range 1 to 1.08 μ with a peak parametric power of 38 × 103 W. The oscillator which was tuned both by rotation of the crystal in an external optical cavity and by the electro-optic effect was pumped at 6943 A by a ruby laser of 3 × 106 W peak power.
Abstract: Optical parametric oscillation has been achieved in LiNbO3 in the range 1 to 1.08 μ with a peak parametric power of 38 × 103 W. The oscillator which was tuned both by rotation of the crystal in an external optical cavity and by the electro‐optic effect was pumped at 6943 A by a ruby laser of 3 × 106 W peak power. The observed electro‐optic tuning agreed with that calculated from measured values of the electro‐optic coefficients.

34 citations


Journal ArticleDOI
TL;DR: In this article, a 500 MW pulsed ruby laser is focussed on to an isolated solid hydrogen pellet in vacuo, and the resulting plasma expands spherically with a front velocity of 2 × 107 cm/sec.

Journal ArticleDOI
TL;DR: In this article, the upper limit of the excitation cross section of this transition was determined and shown to be without effect on the performance of this absorber as a passive Q switch.
Abstract: Measurements carried out on chloroaluminum phthalocyanine under ruby laser excitation showed that the observed blue fluorescence originated in the second excited singlet state and was excited by transitions from the first excited singlet state. The upper limit of the excitation cross section of this transition was determined and shown to be without effect on the performance of this absorber as a passive Q switch. Two‐photon absorption in the chloronaphthalene solvent was also detected.

Journal ArticleDOI
TL;DR: In this article, shadow photography techniques have been used to study various effects produced in transparent liquids by the focused beam from a Q-spoiled ruby laser, including the intense spherical acoustic transients generated in water and other pure liquids when dielectric breakdown occurs.
Abstract: Shadow photography techniques have been used to study various effects produced in transparent liquids by the focused beam from a Q‐spoiled ruby laser. The intense spherical acoustic transients generated in water and other pure liquids when dielectric breakdown occurs have been examined. In solutions of benzanthracene in benzene, in which other workers have detected two‐photon absorption, a linear region is strongly affected by the laser beam and cylindrical acoustic disturbances have been observed.

Journal ArticleDOI
TL;DR: In this study, several extracted noncarious maxillary incisors were prepared for enamel and dentin laser irradiation, and an Ivorine Dentoform tooth was also irradiated, showing only surface irregularities.
Abstract: Laser technology, in just five years after its birth, has opened many intriguing areas of medical research and clinical application. Preliminary tests have shown the pulsed ruby laser to have demonstrable effects on tooth structure in vivo and in vitro. In this study, several extracted noncarious maxillary incisors were prepared for enamel and dentin laser irradiation. An Ivorine Dentoform tooth was also irradiated. The apparatus employed was a focused, pulsed ruby laser head with a 2,000 joule power supply. After lasing, the samples were examined grossly and microscopically: 1.Enamel exhibited gross cratering from 0.1 to 1.1 mm. deep, depending on the amount of energy delivered to the target area. In dentin-deep enamel penetrations, a dark speckling of the exposed dentin subjacent to the lased enamel was observed. Examination under polarized light strongly suggested the presence of laser-induced crystallographic changes in the enamel bordering the enamel craters. 2.Dentin laser impacts yielded shallow, irregular craters less than 0.1 mm. deep. Three distinct zones of dentinal destruction were revealed: (a) a central zone of complete dentinal destruction; (b) an immediately surrounding zone of partial dentinal destruction; and (c) a scattered zone of dark speckling beyond the first two zones. 3.Lased Ivorine demonstrated the mildest effect, showing only surface irregularities. Suggestions are presented for possible future applications of the laser, as the state of the art of laser technology advances. Laser radiation offers exciting possibilities in dental research, oral tumor management, instrumentation, and precision techniques in restorative and prosthetic dentistry. Though laser researchers are presently too committed to the advancement of the state of the art to divert their attention to practical applications, this should not discourage dental investigators from uncovering further the laser's applicability to dentistry.

Journal ArticleDOI
TL;DR: In this paper, it was shown that the electrical breakdown of gases by optical frequency radiation is independent of the instantaneous intensity fluctuations arising from the interaction of modes present in laser radiation, and that the breakdown threshold does not depend upon short term temporal and spatial fluctuations of the power density.
Abstract: Experiments have been carried out which show that the electrical breakdown of gases by optical frequency radiation is independent of the instantaneous intensity fluctuations arising from the interaction of modes present in laser radiation. Gas breakdown thresholds, determined with a single‐mode ruby laser and a phase‐locked neodymium laser are in substantial agreement with published threshold data for conventional, multiple‐mode laser radiation. It was thus determined that the breakdown threshold does not depend upon short term temporal and spatial fluctuations of the power density.

Journal ArticleDOI
TL;DR: In this article, a 500 MW ruby laser is focussed onto a solid hydrogen filament to study the expanding plasma which contains ∼3×1017 particles with several hundred eV average energy.

Journal ArticleDOI
TL;DR: In this article, an apparatus for determining the Raman spectra of molten salts at temperatures up to ca. 1000°C, using a focused laser beam, is described, and the sample volume is 5 ml or less; a technique is described for filtering melts immediately before the spectral measurements.
Abstract: An apparatus is described for determining the Raman spectra of molten salts at temperatures up to ca. 1000°C, using a focused laser beam. The sample volume is 5 ml or less; a technique is described for filtering melts immediately before the spectral measurements. To demonstrate the performance of the apparatus, spectra were obtained for carbon tetrachloride (25°C), molten sodium nitrate (350°C), molten mercuric bromide (270°C), and molten sodium sulfate (900°C). Intensely red‐colored molten mercuric iodide was also characterized (it exhibits one polarized Raman band at 146 Δcm−1). For these tests, 6943 A exciting radiation from a pulsed ruby laser was employed, but the apparatus can in principle be used with other lasers of different frequency. Comparison with spectra obtained using conventional mercury arc excitation shows that the laser compares favorably in the time needed to record spectra, and that spectra are more readily obtainable from high temperature melts and colored systems.

Journal ArticleDOI
TL;DR: In this paper, photographs of holograms made with a single-mode pulsed ruby laser are shown, which are made of a variety of front-lighted motion scenes including a fan rotor, jet spray and hand pouring milk from a beaker.
Abstract: Photographs of holograms made with a single‐mode pulsed ruby laser are shown. Holograms were made of a variety of front‐lighted motion scenes including a fan rotor, jet spray, hand pouring milk from a beaker, and a smoke stream.

Journal ArticleDOI
TL;DR: In this paper, the number of free electrons and neutral atoms in a carbon plasma was determined with two-wavelength interferometry using a Q-switched ruby laser with a peak power of 100 MW and a 3W argon ion laser as the interferometer light source.
Abstract: Experimental determination in a time‐resolved manner of the number densities of free electrons and neutral atoms in a carbon plasma is obtained with two‐wavelength interferometry. The plasma is produced by a Q‐switched ruby laser with a peak power of 100 MW, and a 3‐W argon‐ion laser is used as the interferometer light source. A maximum free electron density of 1.6 × 1019 cm−3 and a maximum neutral density of 1.6 × 1020 cm−3 are observed.

Journal ArticleDOI
TL;DR: In this article, a small rotating prism switched ruby giant pulse laser is reported which, with the aid of a specially designed resonant reflector and moderate cooling, delivers all its available power (∼25 MW) in a spectral width of < 0.01 A.
Abstract: A small rotating prism switched ruby giant pulse laser is reported which, with the aid of a specially designed resonant reflector and moderate cooling, delivers all its available power (∼25 MW) in a spectral width of <0.01 A. It can be used as the oscillator of a high power amplifying system.

Journal ArticleDOI
TL;DR: In this article, a transient interference experiment has been performed using the radiation from a normally spiking, pulsed ruby-laser oscillator, where the laser output at time t is made to interfere with emission corresponding to an earlier time, t −τ, by means of an optical delay inserted into a twopinhole Young's interferometer.
Abstract: A transient interference experiment has been performed using the radiation from a normally spiking, pulsed ruby‐laser oscillator. In the experiment the laser output at time t is made to interfere with emission corresponding to an earlier time, t‐τ, by means of an optical delay inserted into a two‐pinhole Young's interferometer. A light‐pipe photomultiplier oscilloscope system permits photographic recording of the interference fringes during a single spike of the laser emission, with a time resolution of less than 15 nsec. From the data obtained both the fringe visibility and the relative pattern phase of the interference pattern may be evaluated. Data are presented for both visibility and pattern phase for several delay times. The principal observation is that during a single laser spike the frequency increases with time. An analysis of the experiment and of possible causes for frequency variation of the laser with time results in the hypothesis that there is lattice strain in the ruby associated with the...

Journal ArticleDOI
TL;DR: In this paper, the nonlinear electron emission from silver induced by a ruby laser was investigated and the electron current was found to depend nonlinearly on the power density of the beam.

Journal ArticleDOI
T. A. Wiggins1, R. V. Wick1, N. D. Foltz1, C. W. Cho1, D. H. Rank1 
TL;DR: In this article, a high-resolution grating spectrograph of the light from a giant-pulse ruby laser transmitted through the materials revealed the presence of more Stokes-shifted components than can be accounted for on the basis of amplification by the laser of Brillouin-shift frequencies.
Abstract: Optical mixing in 23 liquids and 2 glasses is reported. Observations with a high-resolution grating spectrograph of the light from a giant-pulse ruby laser transmitted through the materials reveal the presence of more Stokes-shifted components than can be accounted for on the basis of amplification by the laser of Brillouin-shifted frequencies. In addition, anti-Stokes-shifted components are observed. The frequency shifts are shown to correspond to those expected for 180° Brillouin scattering. Sound speeds calculated agree in general with those from stimulated and spontaneous scattering experiments. Sound-speed measurements at different temperatures and for two-component liquids give results predictable from bulk properties of the liquids. A number of experiments showing the conditions and the parameters which affect the optical mixing are described.

Journal ArticleDOI
TL;DR: In this paper, a Q-switched ruby laser is used to induce photoconductivity in soda glass, fused quartz, and quartz crystal, and the number of charge carriers produced per laser pulse of 1027 photons cm−2's−1 is accounted for by multiphoton ionization of nonbridging oxygens in the silicon oxygen network.
Abstract: A Q-switched ruby laser is used to induce photoconductivity in soda glass, fused quartz, and quartz crystal. The number of charge carriers produced per laser pulse of 1027 photons cm−2 s−1 is accounted for by multiphoton ionization of nonbridging oxygens in the silicon oxygen network. The relative magnitude of the effect proves that photoconductivity does not result from the ionization of sodium in glass as extensively quoted in the existing literature. The lifetime of the charge carriers produced is estimated to be 10−5 s. Arguments to the effect that this photoconductivity is the primary cause of dielectric breakdown and damage in glasses under excitation by a Q-switched laser are presented.

Journal ArticleDOI
TL;DR: A Q-switched ruby laser was used to produce retinal lesions in rabbits and monkeys and glial reaction was conspicuously deficient, however, two instances of local pigmentcell hyperplasia were observed.
Abstract: A Q-switched ruby laser was used to produce retinal lesions in rabbits and monkeys. The data were obtained with special attention given to eliminating inhomogeneities from the portion of the laser beam entering the eye; correcting each eye for refractive error to produce minimal retinal impact area; estimating the retinal area impacted; monitoring of the laser output in space, time, and amplitude; and to detailed clinical and pathological observations. Eight microjoules in pigmented rabbits and 22μj in rhesus monkeys for 8-nano-second pulses gave a 50% probability of producing a clinically observable lesion. Histologically, lesions were seen at approximately half this level. Energy density or power density at the retina is the determining factor for threshold damage. Histologically, glial reaction was conspicuously deficient. However, two instances of local pigmentcell hyperplasia were observed.

Journal ArticleDOI
TL;DR: In this paper, a special laser cavity made by two roof-top prisms each with roof angle smaller than 90° was described, which gave pure transverse modes of very high quality in pulsed operation.
Abstract: A special laser cavity made by two roof‐top prisms each with roof angle smaller than 90° is described here. Such a cavity has the unique property of giving pure transverse modes of very high quality in pulsed operation.


Journal ArticleDOI
TL;DR: In this article, the authors measured the Fabry-Perot mode spacings of Raman oscillators and found that substantial mode pulling was occurring, interpreted according to mode-pulling theory.
Abstract: Stimulated Raman scattering has been observed in quartz at low temperatures in which the 467 cm−1 Stokes line is split into two or more sharp components. The quartz samples, which were in the form of resonant cavities, behaved as Raman oscillators pumped by a ruby laser. Measurement of the Fabry—Perot mode spacings of the oscillators showed that substantial mode pulling was occurring. This was interpreted according to mode‐pulling theory.

Journal ArticleDOI
01 Jul 1967-Nature
TL;DR: In this article, the authors used a spherical interferometer to measure the time resolved spectra of ruby laser relaxation oscillations and direct spectral detection of off-axis modes in giant pulse ruby lasers.
Abstract: SPHERICAL interferometer fringes have previously been considered unsuitable for the production of a spectrum extending over several orders of the spectral range, chiefly because when the spherical mirrors are separated by exactly their radius of curvature1,2, the order of interference of the fringe pattern decreases as the fourth power of the radius. (With a plane Fabry–Perot instrument, the order of interference varies with the square of the radius.) In practice, however, spherical interferometers have been used successfully to measure the time resolved spectra of ruby laser relaxation oscillations3 and, more recently, for the direct spectral detection of off-axis modes in giant pulse ruby lasers4 and an intensity dependent frequency shift5. In circumstances like these the spherical instrument has the advantage of the high intensity of the illumination of the detector and the fact that the plates are always well adjusted.