Showing papers on "Ruby laser published in 1969"
TL;DR: Raman backscatter of frequency doubled ruby laser beam by water vapor in atmosphere observed by optical radar, calculating water vapor mixing ratio profile profile as mentioned in this paper was used to calculate water vapor mixture profile.
Abstract: Raman backscatter of frequency doubled ruby laser beam by water vapor in atmosphere observed by optical radar, calculating water vapor mixing ratio profile
207 citations
01 Jan 1969
TL;DR: Several experimental techniques for generating, measuring, and utilizing these ultrashort laser pulses are reviewed in this paper, where the experimental results show that they can be used in nonlinear optics, transient response of atomic and molecular systems, optically generated plasmas, spectroscopy, ranging, optical information processing, and high-speed photography.
Abstract: The broad bandwidth and long storage lifetimes of Nd3+: glass and ruby lasers have made possible the generation of picosecond laser pulses having peak powers it excess of one gigawatt and repetition rates in the microwave range. The numerous application areas of these pulses include research in nonlinear optics, transient response of atomic and molecular systems, optically generated plasmas, spectroscopy, ranging, optical information processing, and high-speed photography. This paper reviews several experimental techniques for generating, measuring, and utilizing these ultrashort laser pulses.
181 citations
TL;DR: In this article, the first observation of tunable stimulated optical emission from a nonlinear crystal without the use of an external resonator, and with greater than 50% conversion of the pump beam to the tunable frequency was reported.
Abstract: We report the first observation of tunable stimulated optical emission from a nonlinear crystal without the use of an external resonator, and with greater than 50% conversion of the pump beam to the tunable frequency. Opposite faces of a LiNbO3 crystal were polished flat and parallel to provide for multiple reflections of the signal radiation (Stokes) inside the crystal. The A1 symmetry 248‐cm−1 polariton mode was excited with a Q‐switched ruby laser, and the signal frequency was tuned by varying the angle of incidence of the laser beam relative to the normal to the crystal surface. Operation was at room temperature; no crystal damage was observed over most of the tuning range; and laser depletion occurred within the first few nanoseconds of the Q‐switched pulse. The difference between the Stokes frequency and laser frequency was varied from 42 to 200 cm−1, and the corresponding idler wavelength was varied from 238 to 50 μ.
152 citations
TL;DR: In this paper, the feasibility of utilizing Raman scattering as a diagnostic technique to measure individual specie concentrations in typical gas mixtures found in gas dynamic applications has been investigated and demonstrated.
Abstract: : The feasibility of utilizing Raman scattering as a diagnostic technique to measure individual specie concentrations in typical gas mixtures found in gas dynamic applications has been investigated and demonstrated. Utilizing this technique, either the local density of a pure gas or the concentration of individual diatomic (or polyatomic) species in a gas mixture can be uniquely determined. The range and limitations of this technique were investigated and evaluated under controlled static conditions. A Q-switched ruby laser, which has a pulse duration of approximately 10 nanoseconds, was used as a radiation source. The scattered radiation was monitored utilizing a high gain, wide spectral range photomultiplier tube in conjunction with a spectrograph. Measurements were also made utilizing narrow bandpass filters in place of the spectrograph. The species which were investigated include O2, N2, CO2, and CH4. Quantitative results are given for these gases in their pure state as well as in various mixture proportions. The relative and absolute intensity of the scattered radiation from the species investigated were compared with that predicted by theory. Measurements were also made of the vibrational temperature of O2. A description of the pertinent theory and concepts of Raman scattering is also included as well as a discussion of the limitations of the technique.
72 citations
TL;DR: In this paper, a noncollinear single-cavity optical parametric oscillation with energy conversion of 45% using LiNbO3 pumped with a ruby laser was reported.
Abstract: We report noncollinear single‐cavity optical parametric oscillation with energy conversion of 45% using LiNbO3 pumped with a ruby laser. A new method of tuning is employed. Partial compensation for Poynting vector walk off is provided.
51 citations
TL;DR: In this paper, an experimental technique for obtaining the spatial size and velocity distributions for liquid or solid aerosols suspended in an air flow is described, which leaves the flow undisturbed and allows for a large range of particle sizes and velocities.
Abstract: An experimental technique for obtaining the spatial size and velocity distributions for liquid or solid aerosols suspended in an air flow is described. The technique leaves the flow undisturbed and allows for a large range of particle sizes and velocities. The successful combination of a Q‐spoiled ruby laser and holography was employed to record the desired information. A helium‐neon laser was used to reconstruct the magnified image which was analyzed using closed circuit television.
50 citations
TL;DR: In this article, a Q-switched ruby laser was used to excite the A1 symmetry 248 cm−1 polariton mode in a LiNbO3 crystal, at room temperature, in a resonator external to the laser cavity which was tuned to the Stokes frequency.
Abstract: We report the first observation of tunable stimulated Raman emission. A Q‐switched ruby laser was used to excite the A1 symmetry 248‐cm−1 polariton mode in a LiNbO3 crystal. The crystal, at room temperature, was placed in a resonator external to the laser cavity which was tuned to the Stokes frequency. It was possible to vary the Stokes frequency by altering the angle between the pump beam and the axis of the resonator. Stimulated Raman scattering from other polariton modes (152 cm−1, 628 cm−1) which are potentially tunable was observed. We also report the first observation of stimulated anti‐Stokes emission from a polariton mode.
48 citations
TL;DR: Impacts of the calvarium and rib fragments and laser drillings of sections of polished bone and femurs of the dog were performed and Q switched ruby laser transmission through bone slices has also been studied.
Abstract: DURING an investigation with lasers we carried out impacts of the calvarium and rib fragments1 and, later, laser drillings of sections of polished bone and femurs of the dog were performed (personal communication from R. O. Becker). Q switched ruby laser transmission through bone slices has also been studied3.
38 citations
TL;DR: In this article, a single transverse-mode operation was performed in a mode-locked ruby laser by using a special rooftop prism cavity and adding rhodamine 6G to the dye (DDI in methanol) enabled consistent pulses as short as 5 ps.
Abstract: Picosecond pulses with a single transverse-mode operation have been obtained in a mode-locked ruby laser by using a special rooftop prism cavity. Addition of rhodamine 6G to the dye (DDI in methanol) enabled us to obtain consistently pulses as short as 5 ps.
30 citations
TL;DR: In this article, the first experiment of thermomagnetic writing of a hologram on a thin film of EuO and the reconstruction of the hologram was reported, which was achieved by using a giant pulsed ruby laser as a source for thermomagnetization.
Abstract: In this paper the first experiment of thermomagnetic writing of a hologram on a thin film of EuO and the reconstruction of the hologram is reported. Writing of the hologram is achieved by using a giant pulsed ruby laser as a source for thermomagnetization. Erasing of the hologram is accomplished by a small applied magnetic field. The ruby laser is used because of its ability to provide the energy required for writing in a time that is short compared with the thermo‐relaxation time. A hologram with shallow angle (10 μ resolution) was recorded and the reconstruction of the hologram was done using a He–Ne laser as a source. The formation of the hologram is based on the fact that the index of refraction of the material is a function of magnetization. Thus, the different state of magnetization induced by the laser pulse acts as a phase‐hologram for polarized light. Polarizing elements were used to observe the reconstructed images from the magnetic holograms. Results were also obtained for the diffraction intensity in the different orders of a simple thermo‐magnetic hologram. An analysis is presented to interpret the observed phenomena and gives the calculated efficiency that can be obtained under ideal conditions.
29 citations
TL;DR: LiIO 3 showed strong second harmonic generation of 3470 A when irradiated with a ruby laser as mentioned in this paper, which is the best known second harmonic output of a LiIO 3 crystal.
TL;DR: Compton scattering of ruby laser light from a high energy electron beam at SLAC has been employed to produce a highly polarized, partially monochromatic photon beam of energy up to 7 GeV.
Abstract: Compton scattering of ruby laser light from a high energy electron beam at SLAC has been employed to produce a highly polarized, partially monochromatic photon beam of energy up to 7 GeV.
TL;DR: In this paper, a 9MW ruby laser beam was used to produce optical parametric noise in a centrosymmetric medium, water, by a phase matched four-photon process.
Abstract: Optical parametric noise has been produced in a centrosymmetric medium, water, by a 9‐MW ruby laser beam. The wavelengths, in the visible, and the angles of emission agree with the tuning curve calculated for a phase‐matched four‐photon process. A power of ≈½μW emitted into a 38‐A band is observed in the low‐loss wavelength range, in approximate agreement with theory. Very strong idler absorption has little apparent effect on the signal power or bandwidth.
TL;DR: Experimental results are presented to show that hologram efficiencies of 1.2% can be obtained with photochromic SrTiO(3) materials and that patterns of 10(4) bits/cm(2) can be read out up to 10(7) times before destroying the stored information.
Abstract: Experimental results are here presented to show that hologram efficiencies of 1.2% can be obtained with photochromic SrTiO3 materials and that patterns of 104 bits/cm2 can be read out up to 107 times before destroying the stored information. It is also shown that the nonlinear absorption properties of the material can be used to store holograms at the ruby laser wavelength where the materials are nominally transparent in the ground state.
TL;DR: In this article, the temperature of a laser-heated carbon plasma, formed by the interaction between a Q-switched ruby laser and a pyrolytic graphite slab, has been measured using interferometric, spectroscopic, and energy conservation techniques.
Abstract: The temperature of a laser‐heated carbon plasma, formed by the interaction between a Q‐switched ruby laser and a pyrolytic graphite slab, has been measured using interferometric, spectroscopic, and energy conservation techniques. Results indicate that the maximum plasma temperature is less than 10 eV. A method of determining whether the plasma is in thermodynamic equilibrium is employed and indicates that at laser fluxes of 109 W/cm2 the plasma is not in LTE with the electron temperature nearly an order‐of‐magnitude larger than the plasma temperature. For fluxes of 1010 W/cm2, however, the plasma appears to approach a state of thermodynamic equilibrium with a temperature of 2eV.
TL;DR: In this paper, the propagation of thermally generated stress waves in a dispersive elastic rod was investigated both experimentally and analytically both in terms of the number of stress waves and their propagation speed.
Abstract: The propagation of thermally generated stress waves in a dispersive elastic rod was investigated both experimentally and analytically.
TL;DR: In this paper, it was shown that the subsequent pump light absorption by these color centers, which serves to deplete the pumping energy internally in the rod and to cause bulk absorption loss at 6943 A, fully explains the degradation observed to within the limits of experimental error.
Abstract: The use of lasers in rangefinding and other applications requires that the laser be capable of being fired many times without its output characteristics changing substantially. A gradual reduction in ruby (Cr3+ in Al2O3) laser output energy has been observed during repeated firing of the laser. This degradation is found to occur with varying degrees of severity in all ruby rods tested. We have traced this to the formation of color centers within or on the surface of the ruby rod: defects, impurities, etc., present before exposure can be converted into color centers by the blue and ultraviolet content of the pumplight. Conversion of Cr3+ to other valence states is very small, amounting to less than 1% of the total Cr3+ density (the sensitivity of the measurement) for most samples and to 3% for one vintage of ruby. The radiation induced absorption which was found agrees well with x‐ray induced color‐center absorption in undoped α‐Al2O3 rather than absorption by Cr2+ or Cr4+. We have shown that the subsequent pump light absorption by these color centers, which serves to deplete the pumping energy internally in the rod and to cause bulk absorption loss at 6943 A, fully explains the degradation observed to within the limits of experimental error. A reliable indicator of color center formation is the orange‐brown appearance which develops in the ruby; only a partial restoration of output energy can be achieved by heating the rods at 900°C for 24 h; the use of pyrex to filter the ultraviolet from the pump light can reduce but not eliminate the rate of energy decay. The contribution of this work is that we have determined the principal mechanisms out of several possible ones which explains the energy decay observed in U.S. grown ruby samples. The complete solution to this problem will be known when it is understood how to prevent color center formation in Al2O3 upon ultraviolet irradiation.
01 Aug 1969
TL;DR: Results of experimental investigations of threshold levels for small retinal lesions are presented and a report on the histopathology of retinal injury in rhesus monkeys due to Q-switched neodymium and argon lasers is included.
Abstract: : Results of experimental investigations of threshold levels for small retinal lesions are presented. Data for rhesus monkeys include thresholds for a Q-switched neodymium laser, both in the macula and in the paramacular area. In addition, extensive data are presented for argon, helium-neon, and neodymium-YAG laser damage threshold. Exposures of human volunteers to various lasers are reported. The lasers used were Q-switched neodymium and ruby lasers, a long- pulse ruby laser, and an argon laser. A report on the histopathology of retinal injury in rhesus monkeys due to Q-switched neodymium and argon lasers is included.
TL;DR: In this article, the formation and arrangement of microcraters produced by an unfocused pulse of power density ∼ 100 MW/cm2 was discussed, where the pulses, of width 1.0 × 10−8 s, were generated by a ruby laser, Q-switched by vanadyl phthalocyanine.
Abstract: Q-SWITCHED laser pulses focused on to a metal cause microcraters at the surface1,2. This communication deals with the formation and arrangement of microcraters produced by an unfocused pulse of power density ∼ 100 MW/cm2. The pulses, of width 1.0 × 10−8 s, were generated by a ruby laser, Q-switched by vanadyl phthalocyanine.
TL;DR: An experiment to record a holographic motion picture is described in this article, where the source of illumination is a cw ruby laser operated in the repetitively Q•switched mode, recorded at the rate of 20 frames per second on 100 ft of 70mm film, transported by a conventional 70mm sequential-still camera.
Abstract: An experiment to record a holographic motion picture is described. The source of illumination is a cw ruby laser operated in the repetitively Q‐switched mode. The film was recorded at the rate of 20 frames per second on 100 ft of 70‐mm film, transported by a conventional 70‐mm sequential‐still camera. The subject of the movie was a group of tropical fish.
TL;DR: In this paper, the effect of inserting an element exhibiting induced absorption into a Q-switched laser cavity is investigated theoretically and experimentally, and the rate equations are solved assuming two types of nonlinear loss, one being proportional to the square of the laser intensity and the other being proportionally to the product of the intensity and density of excited electrons in the nonlinear absorber.
Abstract: The effect of inserting an element exhibiting induced absorption into a Q -switched laser cavity is investigated theoretically and experimentally. The rate equations are solved assuming two types of nonlinear loss, one being proportional to the square of the laser intensity and the other being proportional to the product of laser intensity and density of excited electrons in the nonlinear absorber. Experiments are performed with a rotating-prism ruby laser with a CdS crystal in its cavity. It is established that two-photon absorption takes place, and as predicted by the theory that the output intensity and output energy both decrease and pulse length increases as compared with the normal Q -switched case. In addition, the output pulse has an oscillatory behavior, and it is suggested that this is caused by loss due to the excited electrons, which are found to have a lifetime of approximately 24 ns.
01 Aug 1969
TL;DR: In this article, a non-linear absorption is obtained by using a Rayleigh-wing scatterer as the solvent for a bleachable dye, which is unique in that stretched Q-switched pulses may be obtained by the introduction of a single liquid into the laser resonator with no electronics necessary.
Abstract: Pulse stretching of a passively Q-switched ruby laser is accomplished by the introduction of a non-linear absorber into the laser cavity. Single pulses of length 150 to 400 nsec are observed. The non-linear absorption is obtained by using a Rayleigh-wing scatterer as the solvent for a bleachable dye. This approach is unique in that stretched Q-switched pulses may be obtained by the introduction of a single liquid into the laser resonator with no electronics necessary. Since the Rayleigh Frequency is within the gain lineshape of the active medium, threshold for the stimulated Rayleigh scattering is exceeded at relatively low power densities.
TL;DR: In this paper, an ultra-high-speed multiple-frame recording system for two-and three-dimensional dynamic photomechanics has been developed and is described by using the output from a ruby laser modulated with a Pockels cell to produce a train of short, intense, monochromatic and polarized light pulses.
Abstract: An ultrahigh-speed multiple-frame recording system for two- and three-dimensional dynamic photomechanics has been developed and is described here. The output from a ruby laser is modulated with a Pockels cell to produce a train of short, intense, monochromatic and polarized light pulses. Pulse widths of 50 nsec and repetition rates of up to 170,000 pulses/sec are obtained. These light pulses are synchronized with a “smear camera” and the event to produce a multiple-frame record of the phenomenon. The simplified camera requirements necessary for this purpose are indicated. The system is demonstrated by recording two-dimensional dynamic and scattered-light isochromatic fringe patterns. The capability of multiple recording of scattered-light fringe patterns, achieved here for the first time, has a tremendous potential for three-dimensional dynamic stress analysis. The developed system is also well suited for dynamic moire, interferometry and holography.
TL;DR: A replica technique and electron microscopy have been applied to the study of ruby laser damage on germanium surfaces as discussed by the authors, where the damage produced at very low laser energies far from t
Abstract: A replica technique and electron microscopy have been applied to the study of ruby laser damage on germanium surfaces Studies were made of the damage produced at very low laser energies far from t
Patent•
18 Dec 1969TL;DR: In this article, the authors proposed a method to generate range contours with distances on the order of 5 millimeters or more by utilizing a ruby or other solid laser, where one of the two boundaries of the optical cavity is formed by a suitable mode selector, such as a Fabry-Perot resonant reflector, a prism or a grating.
Abstract: A ruby or other solid laser is made to generate two or more closely adjacent optical frequencies. By illuminating an object to be recorded holographically with the laser light, range contours are generated when the hologram is reconstructed. The range contours can be made to have distances on the order of 5 millimeters or more by utilizing a ruby laser. To this end, one of the two boundaries of the optical cavity for the laser is formed by a suitable mode selector, such, for example, as a Fabry-Perot resonant reflector, a prism or a grating. The thickness of the resonant reflector is so selected that two or more frequencies may be generated within the lasing linewidth of the laser. Preferably, in order to obtain better contrast, the optical length of the cavity is a multiple of the optical thickness of the resonant reflector. The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; 42 U.S.C. 2457).
TL;DR: In this article, a method for locking the longitudinal modes of a laser resonator and generating ultrashort pulses of light is described, where the cavity modes are coupled together when a medium with a refractive index nonlinearity is placed in the cavity.
Abstract: A new method for locking the longitudinal modes of a laser resonator and generating ultrashort pulses of light is described. The cavity modes are coupled together when a medium with a refractive index nonlinearity is placed in the cavity. A theoretical study is presented which analyzes the mode structure of a laser resonator containing a cell filled with an anisotropic molecular liquid. It is found that under certain conditions the energy exchange between the modes gives rise to a mode-locked spectrum and to the attendant generation of ultrashort pulses of light ( \sim 10^{-11} second for a ruby laser, 10-12second for a Nd3+: glass laser).
TL;DR: In this article, the Schubweg per unit electric field (called range) was investigated as a function of the concentration of absorbed photons in the volume of ZnO-single crystals.
Abstract: In the volume of ZnO-single crystals a high concentration of free electrons was generated by two-photon absorption of ruby laser pulses. With regard to the different lifetimes of the moved electrons parallel and perpendicular to thec-axis influenced charges could be measured, which result only from the thermal motion of the electrons. With an applied voltage the Schubweg per unit electric field (called range) was investigated as a function of the concentration of absorbed photons. During irradiation with the laser pulse a pressure wave is caused by the thermal diffusion of the electrons; the arrival of the pressure wave on the electrodes in thec-direction was measured by the piezoelectric effect.
TL;DR: The atmospheric attenuation of a ruby laser beam is studied and the possibility of using the laser back scattered radiation to probe optical visibility is investigated.
Abstract: The atmospheric attenuation of a ruby laser beam is studied. The possibility of using the laser back scattered radiation to probe optical visibility is investigated. Some experimental measurement supporting this possibility is reported.