Showing papers on "Ruby laser published in 1995"
01 Jan 1995
TL;DR: The use of lasers in surgery introduces some desirable features such as increased precision, improved hemostasis, and less tissue manipulation.
Abstract: Medical use of lasers began soon after the first ruby laser was invented in 1960.1 Laser radiation is now used routinely in surgery to incise, coagulate, or vaporize tissues. The use of lasers in surgery introduces some desirable features such as increased precision, improved hemostasis, and less tissue manipulation.2 The biological effects of laser energy depend on the laser wavelength, the irradiance, the duration of irradiation, and optical as well as thermal properties of the tissue involved. The laser-tissue interaction mechanisms may be thermal, photochemical, or mechanical in nature. Surgical procedures that involve coagulation or ablation of tissue are thermal.
159 citations
Journal Article•
TL;DR: The Q-switched ruby laser was found to be superior in lightening black dye in both professional and amateur tattoos, and a significant advantage was noted for the ruby laser in the removal of green tattoo pigment.
Abstract: The Q-switched ruby and the Q-switched neodymium YAG lasers are both widely used in the treatment of amateur and professional tattoos. Comparative evaluation of these two laser systems has not previously been performed; thus, the advantages of each laser have not been delineated. Forty-eight amateur and professional tattoos were treated with both the Q-switched ruby and Q-switched Nd:YAG lasers. The tattoos were divided in half and one side of the tattoo was treated with each laser. After one treatment, the patients returned for evaluation to assess the degree of lightening achieved by each laser. The Q-switched ruby laser was found to be superior in lightening black dye in both professional and amateur tattoos. A significant advantage was noted for the ruby laser in the removal of green tattoo pigment. The differences with the Q-switched ruby laser and the 1064 nm option of the Q-switched YAG laser were not clinically significant in the lightening or removal of other colors. The 532 nm option of the Q-switched YAG laser was superior to the Q-switched ruby and the 1064 nm option of the YAG laser in the removal of red tattoo colors in professional tattoos. Hypopigmentation was found more commonly with the Q-switched ruby laser, while textural change was noted more commonly with the Q-switched Nd:YAG laser. One of the patients treated with the Nd:YAG laser at 1064 nm showed a hypertrophic scar.
89 citations
TL;DR: The Q-switched ruby laser has been used to treat a number of cutaneous lesions, including lentigines, 1 tattoos, and nevus of Ota, and management of congenital nevi has been the subject of much debate over the past decade.
Abstract: The Q-switched ruby laser has been used to treat a number of cutaneous lesions, including lentigines, 1 tattoos, and nevus of Ota. 2 The Q-switched ruby laser emits visible red light with a wave-length of 694 nm and pulse duration of 28 to 40 nanoseconds. This relatively long wavelength and short pulse duration allow for the absorption of laser energy into the dermis with minimal textural changes. Laser energy is selectively absorbed by both keratinocytes and melanocytes containing melanosomes. Although melanin in these melanosomes has an absorption spectrum that is highest in the UV range, diminishing toward the infrared range, there is minimal competitive absorption of ruby energy (694 nm) by oxyhemoglobin. 3 Management of congenital nevi has been the subject of much debate over the past decade. This stems from the unresolved controversy concerning their potential for malignant degeneration, specifically to malignant melanoma. We report on the use
63 citations
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TL;DR: Different lasers, laser tissue interaction and clinical laser applications relevent to urology are reviewed.
Abstract: Ever since Mulvany first described use of Ruby laser for lithotripsy, urologists have been exploiting every possible application of this technology. Laser lithotripsy in the 1980s and now laser prostatectomy in the 1990s have dominated laser usage in urology. Applications of lasers for superficial lesions (e.g., condylomata acuminata and carcinoma of penis) have found an established role. Interests in laser welding, photodynamic therapy and fluorescence continues to grow and evolve. The laser industry at the same time is striving to provide more efficient lasers. High power lasers (Holmium:YAG, KTP:YAG) and laser machines combining double wavelengths (Nd:YAG and KTP, Ho: YAG and Nd:YAG) are commercially available. Diode lasers with their portability and reliability qualities can now provide high output powers in various wavelengths. Here, we have reviewed different lasers, laser tissue interaction and clinical laser applications relevent to urology.
58 citations
Book•
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17 Mar 1995
TL;DR: In this article, the authors present a survey of the properties of three-level and four-level LIDAR sources and their application in chemistry, physics, and other fields.
Abstract: 1 Principles of Laser Operation.- 1.1 The Nature of Stimulated Emission.- 1.2 Resonators and Pumping Processes.- 1.3 Coherent Radiation, Standing Waves and Modes.- 1.4 The Kinetics of Laser Emission.- 1.4.1 Rate Equations.- 1.4.2 Threshold Conditions.- 1.4.3 Pulsed Versus Continuous Emission.- 1.5 Transitions, Lifetimes and Linewidths.- 1.5.1 Three-level Laser.- 1.5.2 Four-level Laser.- 1.5.3 Emission Linewidths.- 1.6 Properties of Laser Light, and Their Applications.- 1.6.1 Beamwidth.- 1.6.2 Intensity.- 1.6.3 Coherence.- 1.6.4 Monochromaticity.- 1.7 Questions.- 2 Laser Sources.- 2.1 Optically-pumped Solid-state Lasers.- 2.1.1 Ruby Laser.- 2.1.2 Neodymium Lasers.- 2.1.3 Tunable Lasers.- 2.2 Semiconductor Lasers.- 2.3 Atomic and Ionic Gas Lasers.- 2.3.1 Helium-Neon Laser.- 2.3.2 Argon Laser.- 2.3.3 Copper Vapour Laser.- 2.4 Molecular Gas Lasers.- 2.4.1 Carbon Dioxide Laser.- 2.4.2 Nitrogen Laser.- 2.4.3 Chemical Lasers.- 2.4.4 Iodine Laser.- 2.4.5 Excimer Lasers.- 2.5 Dye Lasers.- 2.6 Free-electron Laser.- 2.7 Questions.- 3 Laser Instrumentation in Chemistry.- 3.1 Polarising Optics.- 3.2 Frequency Conversion.- 3.2.1 Dye Laser Conversion.- 3.2.2 Non-linear Optics.- 3.2.3 Raman Shifting.- 3.3 Pulsing Techniques.- 3.3.1 Cavity Dumping.- 3.3.2 Q-Switching.- 3.3.3 Mode-locking.- 3.4 Detectors.- 3.5 Pulse Detection Systems.- 3.5.1 Lock-in Amplifiers.- 3.5.2 Boxcar Integrators.- 3.5.3 Single-pulse Systems.- 3.6 Light Scattering Instrumentation.- 3.6.1 Nephelometry.- 3.6.2 Photon Correlation Measurements.- 3.6.3 Brillouin Scattering.- 3.6.4 Doppler Velocimetry.- 3.6.5 Lidar.- 3.7 Polarimetry.- 3.8 Laser Detectors in Chromatography.- 3.9 Laser Microprobe Instrumentation.- 3.10 Laser Safety.- 3.11 Questions.- 4 Chemical Spectroscopy with Lasers.- 4.1 Absorption Spectroscopy.- 4.2 Specialised Absorption Techniques.- 4.2.1 Excitation Spectroscopy.- 4.2.2 Ionisation Spectroscopy.- 4.2.3 Thermal Lensing Spectroscopy.- 4.2.4 Photoacoustic Spectroscopy.- 4.2.5 Optogalvanic Spectroscopy.- 4.2.6. Laser Magnetic Resonance.- 4.2.7 Laser Stark Spectroscopy.- 4.2.8 Supersonic Jet Spectroscopy.- 4.2.9 Other High-resolution Methods.- 4.3 Fluorescence Spectroscopy.- 4.3.1 Laser-Induced Atomic Fluorescence.- 4.3.2 Laser-Induced Molecular Fluorescence.- 4.4 Raman Spectroscopy.- 4.5 Specialised Raman Techniques.- 4.5.1 Resonance Raman Spectroscopy.- 4.5.2 Stimulated Raman Spectroscopy.- 4.5.3 Inverse Raman Spectroscopy.- 4.5.4 CARS Spectroscopy.- 4.5.5 Surface-enhanced Raman Spectroscopy.- 4.5.6 Raman Optical Activity.- 4.6 Multiphoton Spectroscopy.- 4.6.1 Single-beam Two-photon Absorption.- 4.6.2 Double-beam Two-photon Absorption.- 4.6.3 Multiphoton Absorption Spectroscopy.- 4.6.4 Hyper-Raman Spectroscopy.- 4.7 Laser Mass Spectrometry.- 4.8 References.- 4.9 Questions.- 5 Laser-Induced Chemistry.- 5.1 Principles of Laser-induced Chemistry.- 5.1.1 Features of Laser Excitation.- 5.1.2 Laser-initiated Processes.- 5.2 Multiphoton Infra-red Excitation.- 5.2.1 Diatomic Molecules.- 5.2.2 Polyatomic Molecules.- 5.2.3 Reaction Rates and Yields.- 5.3 Laser Photochemical Processes.- 5.3.1 Unimolecular Laser-induced Reactions.- 5.3.2 Bimolecular Laser-enhanced Reactions.- 5.3.3 Laser-sensitised Reactions.- 5.3.4 Ultrafast Reactions.- 5.3.5 Laser Reaction Diagnostics.- 5.4 Isotope Separation.- 5.4.1 Photoionisation.- 5.4.2 Photodissociation.- 5.4.3 Photochemical Reaction.- 5.4.4 Photodeflection.- 5.5 Materials Applications.- 5.5.1 Laser Surface Chemistry.- 5.5.2 Purification of Materials.- 5.5.3 Production of Ceramic Powders.- 5.5.4 Laser-initiated Polymerisation.- 5.6 Photodynamic Therapy.- 5.7 References.- 5.8 Questions.- Appendix 1: Listing of Output Wavelengths from Commercial Lasers.- Appendix 2: Directory of Acronyms and Abbreviations.- Appendix 3: Selected Bibliography.- Appendix 4: Answers to Numerical Problems.
53 citations
TL;DR: In this article, a 4 Hz version of the ruby laser was developed to enhance the rate of cycling of detection and digitizing to match, and the first profiles obtained with the new system are presented.
Abstract: The LIDAR Thomson scattering technique uses the time of flight of a short laser pulse to spatially resolve measurements of electron temperature (Te) and density (ne) in a plasma. The technique was pioneered at JET and the first profiles were obtained in 1986. The initial system used a 3 J, 0.5 Hz, 300 ps ruby laser and microchannel‐plate photomultiplier detectors to make Te and ne profile measurements with ∼10 cm spatial resolution. Since then we have sought to improve both the spatial resolution and frequency of measurement during a JET pulse. It has proved possible to develop a 4 Hz version of the ruby laser and to enhance the rate of cycling of detection and digitizing to match. The main LIDAR system has now been upgraded to 4 Hz and first JET profiles obtained with the new system are presented. For a LIDAR system, the spatial resolution δL along the laser path is given by δL=(c/2)(τ2L+τ2D)1/2, where c is the velocity of light, τL the laser pulse width, and τD the detection system response time. Over a...
51 citations
TL;DR: Despite of the risk of discoloration, the ruby laser is one of the most effective tools for therapy of pigmented epidermal nevus.
Abstract: The pulsed ruby laser has a selective thermolytic effect. Recently, it has been available for the treatment of superficial pigmented disorders. We studied 5 cases of epidermal nevus treated with the pulsed ruby laser. In comparison with the usual methods including electrocautery, cryotherapy and skin abrasion, ruby laser therapy is an excellent tool due to technological ease and rapid improvement. Depigmentation after treatment in 2 cases was the only side effect of this therapy. Bose cases had a dark pigmentation of the skin. Despite of the risk of discoloration, the ruby laser is one of the most effective tools for therapy of pigmented epidermal nevus.
38 citations
TL;DR: The successful long-term elimination of common blue nevus is reported on the nasal skin of two patients whose lesions were treated with the laser emission of 694 nm energy from the Q-switched ruby laser.
Abstract: The common blue nevus is a benign, localized collection of dermal melanocytes. To date, removal required excisional surgery to eliminate pigment that usually extends into the reticular dermis. We report the successful long-term elimination of common blue nevi on the nasal skin of two patients whose lesions were treated with the laser emission of 694 nm energy from the Q-switched ruby laser.
25 citations
TL;DR: The Q-switched ruby laser, the pulsed dye laser, and the Photoderm VL show excellent results in the treatment of lesions of the skin, which otherwise would have been difficult to treat of untreatable.
Abstract: BACKGROUND Two new types of lasers, the pulsed dye laser and the Q-switched ruby laser, have shown good to excellent results in the treatment of vascular malformations and benign pigmented lesions of the skin. A new and very effective alternative to pulsed dye laser is the recently introduced Photoderm VL. This device is based on the use of a wide-band non-coherent intense pulsed light source which emits a continuous spectrum in the range of 515 nm to 1200 nm. PATIENTS AND METHODS More than a 1000 patients with a variety of lesions of the skin were treated by these new laser systems and the Photoderm VL. The Q-switched ruby laser (wavelength 694 nm, pulse duration 25 ns) is suitable for the treatment of benign lentigines, cafe-au-lait macules, seborrhoic ceratosis, tattoos, and traumatic tattoos. The pulsed dye laser (585 nm, 0,3-0,45 ms) treats nevi flammei, capillary hemangiomas, telangiectasias, xanthelasma, hypertrophic scarring, and adenoma sebaceum. In addition we present the facilities of the new Photoderm VL (515 nm-1200 nm, 0,5-20 ms) for the treatment of nevi flammei, benign hemangiomatous malformations, telangiectasias, erythrosis interfollicularis colli, hypertrophic scarring, and hypertrichosis. RESULTS AND CONCLUSIONS the Q-switched ruby laser, the pulsed dye laser, and the Photoderm VL show excellent results in the treatment of lesions of the skin, which otherwise would have been difficult to treat of untreatable. The efficiency of the laser types presented is based on the theory of selective photothermolysis. Scarring is almost never seen and hypo- or hyperpigmentation is in most cases transient.
22 citations
TL;DR: In this paper, the results of absorption saturation measurements in the visible on chromium-doped Y2SiO5, Gd2SiOsO5 and Mg2NiO4 crystals were reported.
Abstract: The results of absorption saturation measurements in the visible on chromium-doped Y2SiO5, Gd2SiO5 and Mg2SiO4 crystals are reported. The cross-sections for ground state and excited state absorption of Cr4+ ion in distorted tetrahedral sites are estimated at 694 nm. Saturable absorber Q-switching of a ruby laser using Cr-doped Y2SiO5 and Mg2SiO4 is described.
21 citations
TL;DR: In this paper, computer calculations based on the Fourier equation of the heat flow are reported for both excimer and ruby laser irradiation of silicon substrates implanted with Ge and Si ions.
Abstract: Computer calculations based on the Fourier equation of the heat flow are reported for ruby and excimer laser irradiation of silicon substrates implanted with Ge and Si ions. The calculated thresholds for the epitaxial crystallization are compared to the experimental values determined by Rutherford backscattering spectrometry (R BS) and channeling measurements. Good agreement is achieved between calculated and experimental values for ruby laser irradiation of Si and Ge implanted samples, while for the excimer laser irradiation of Ge implanted samples the numerical simulations do not agree with the experimental values. A reduced reflectivity of the surface during the melting of the Ge implanted samples must be considered in order to reproduce the experimental data. The study indicates that a complicated melting dynamics occurs during laser irradiation with the excimer laser with an inhomogeneous melting caused by the Gaussian Ge concentration profile.
TL;DR: In this paper, photoacoustic spectroscopy (PAS) was used to find an effective laser source to ignite energetic materials, and the absorption spectra of some energetic materials are obtained by means of a photoacoustical analyzer.
Abstract: To find an effective laser source to ignite energetic materials, the absorption spectra of some energetic materials are obtained by means of a photoacoustic spectroscopy (PAS). In this experiment, PAS covers the wavelength region of 400 nm-1600 nm in which no other conventional method can take absorption spectra for powdered energetic materials. Photoacoustic spectra of 18 energetic materials are reported. In general, energetic materials tested showed peaks in 600 nm–800 nm and 1400 nm–1600 nm ranges. It is found that the energy required to initiate explosives in the case of ruby laser initiation were correlated with their photoacoustic signal intensities.
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TL;DR: In this article, the authors proposed an extension of free electron laser (FEL) to XUV wavelength range, which is obtained by focusing a very intense laser beam (typically more than 1015 Wcm−2) in a rare gas jet.
Abstract: Emission of coherent radiation in the X-ray wavelength range has been a challenge since the early ruby laser in 19601. Several paths of research are now followed to progress towards soft X-rays: one option is production of high-order harmonics of a visible or infrared laser. That is obtained by focusing a very intense laser beam (typically more than 1015 Wcm−2) in a rare-gas jet2; the emission thus generated preserves the coherence properties of the pump emission, but efficiency is low. Another possibility consists in the extension of free electron lasers (FEL) to XUV wavelength range3. Actual FELs operate in the visible range and proposals for XUV FELs call for very large and sophisticated wigglers and result into high projected cost of such machines.
TL;DR: In this paper, a novel technique for the injection of small (diameter ≤ 30 μm) impurity pellets into fusion plasmas is proposed and investigated, which may be easily applied by using a special target plate in conventional laser blow-off injection devices.
Abstract: A novel technique for the injection of small (diameter ≤30 μm) impurity pellets into fusion plasmas is proposed and investigated. The method may be easily applied by using a special target plate in conventional laser blow‐off injection devices. In the present experiments 10×30×30 μm size aluminum pellets (≊5×1014 atoms) are accelerated to average velocities up to 1 km/s by a 700 mJ ruby laser pulse. The scaling law obtained from a rocket model to the pellet velocity versus laser fluence fits well to experimental data and enables one to extrapolate the capabilities of the technique.
TL;DR: The dual laser produced plasma (DLP) technique has been used to study the EUV absorption spectra of germanium plasmas in the 50-400 AA region as discussed by the authors.
Abstract: The dual laser produced plasma (DLP) technique, has been used to study the EUV absorption spectra of germanium plasmas in the 50-400 AA region. The absorbing plasmas were produced by focusing the output of a Q-switched ruby laser onto a germanium target while the background continuum was produced by focusing the output of a Nd:YAG oscillator/amplifier system onto a samarium target. At a time delay of 50 ns and an absorbing plasma column length of 2 mm the spectrum recorded was predominantly due to Ge2+. We have investigated 3d and 3p sub-valence transitions. In the former, 3d104s2 to 3d94s2nf and 3d94s2np series converging on the 2D5/2 and 2D3/2 limits of Ge3+ were identified by isoelectronic comparison and Hartree-Fock calculations. In the 3p case no strong line transitions were observed which was shown by many body calculations to result from line broadening caused primarily by super Coster-Kronig decay of the 3p hole.
TL;DR: In this article, the absorption saturation in Cr4+-activated Mg2SiO4 and Y 2SiO5 crystals was studied, and the cross sections were calculated for the absorption of 694 nm light by the ground 3A2(3F) and the excited 3T2(2F) states.
Abstract: The absorption saturation in Cr4+-activated Mg2SiO4 and Y2SiO5 crystals was studied. The cross sections were calculated for the absorption of 694 nm light by the ground 3A2(3F) and the excited 3T2(3F) states. A ruby laser was passively Q-switched by Mg2SiO4 : Cr4+ and Y2SiO5 : Cr4+ crystals. The duration and energy of the output pulses were τ = 100 ns and E = 0.24 J.
TL;DR: In this paper, the authors proposed an optical system to increase the photon yield by about a factor of 7, where the trapped laser beam recirculates about 14 times through the sampling volume which is part of the cavity, increasing the laser energy of 25 J to an effective energy of about 140 J.
Abstract: Multiposition tangential Thomson scattering makes it possible to measure the profiles of the local drift velocity and current density of a tokamak plasma. To achieve a reasonably small observational error (20%) a high photon yield is required. In this paper we propose an optical system to increase the photon yield by about a factor of 7. Photons from a pulsed ruby laser are captured in a ring cavity by means of an electro‐optical switch. The trapped laser beam recirculates about 14 times through the sampling volume which is part of the cavity, increasing the laser energy of 25 J to an effective energy of about 140 J.
TL;DR: In this article, the temperature fields associated with dry sliding contact were determined by using laser speckle photography, which measured deformations which occur on the edge of a rectangular-sectioned pin which is sliding against a counterface disc.
01 Jan 1995
TL;DR: In this article, a synthese sur les different types of lasers: nom des materiaux et longueur d'onde d'emission, nom des longueurs d'de lignes d'ensemblages, etc.
Abstract: Article de synthese sur les differents types de lasers: nom des materiaux et longueur d'onde d'emission
23 Aug 1995
TL;DR: In this paper, the principle of a technique to produce planar and volumetric plasma sources of nearly every element and results of experiments on verification of this technique are described and compared.
Abstract: In this paper, we describe the principle of a technique to produce planar and volumetric plasma sources of nearly every element and results of experiments on verification of this technique. This technique is based on a generalization of the LIBORS-process (laser ionization based on resonant saturation) which because of its similarity to chemical catalytic reactions has been called CATRION (CATalytic Resonance IONization). Characteristics of vapor clouds formed near wide variety of mono-component or two-component targets in vacuum with a pulsed ruby laser were investigated. Effect of an intense KrF laser radiation on expanding tantalum-contained and, for comparison, titanium vapor clouds was studied. Photoresonance ionization in saturation mode of tantalum cloud was detected with the help of a frame camera, Langmuir probes, and spectroscopic diagnostics.
Journal Article•
TL;DR: In this paper, a high spatial resolution Thomson scattering system is installed on JFT-2M tokamak, which is composed of two stages of gateable image intensifier tubes fiber optically coupled to a cooled CCD.
Abstract: I Abstract A high spatial resolution rv Thomson scattering system is installed on JFT-2M tokamak. This system has beeri providing complete profiles of T. and n* at a single time during a plasma discharge. A new ICCD detector system with the input diameter of 80 mm is composed of two stages of gateable image intensifier tubes fiber optically coupled to a cooled CCD. The extinction ratio of image intensifier is over 107i and the resolution of each tube is 20 Ip/mm on axis to correspond to 3 13 Ip/channel. The rise time and fluctuation of gate pulse are 2 3 ns and < 4\"/. for 120 ns pulse, res pectively.
Journal Article•
TL;DR: A patient with benign lentigo labialis, who showed total resolution of the lesion after a single ruby laser application, is treated.
Abstract: The Q.switched ruby laser has shown excellent results in the treatment of tattoos. This laser has a wavelength of 694 nm and a pulse duration of 25 ns and causes selective destruction of pigments in the skin. This report is on a patient with benign lentigo labialis, who showed total resolution of the lesion after a single ruby laser application.
TL;DR: Stimulated Raman scattering of mode-locked ruby laser radiation in SF6 and hydrogen was used to generate pulses of 0.5 ps duration and 0.1 mJ energy at the wavelength of 1.056 μm.
Abstract: Stimulated Raman scattering of mode-locked ruby laser radiation in SF6 and hydrogen was used to generate pulses of 0.5 ps duration and of 0.1 mJ energy at the wavelength of 1.056 μm. Amplification of the pulses in a single-pass (12 cm long) neodymium phosphate glass amplifier increased the energy to 0.5 mJ and the measured contrast ratio of the pulses exceeded 1012.
Journal Article•
TL;DR: Three patients with amateur and traumatic tattoos, which were removed by Q-switched ruby laser treatment without leaving scars, are reported on.
Abstract: The Q-switched ruby laser with a wavelength of 694 nm and a pulse duration of 25 ns causes selective damage to skin pigment. This laser has produced good to excellent results in the treatment of amateur professional and traumatical tattoos, and also of benign pigmented lesions such as lentigines, ephelides, cafe-au-lait spots and Becker nevi. We report on three patients with amateur and traumatic tattoos, which were removed by Q-switched ruby laser treatment without leaving scars.
TL;DR: In this article, a wavefront conjugation of free-running ruby laser by using thermal nonlinearity in dye-activated nematics is demonstrated, where the conjugations coefficient near phase transition to isotropic state are close to 100 %.
Abstract: Wavefront conjugation (WFC) of free-running ruby laser by using thermal nonlinearity in dye- activated nematics is demonstrated. Obtained values of the conjugation coefficient R near phase transition to isotropic state are close to 100 %. Temperature dependence of R has been studied theoretically and experimentally.
TL;DR: In this paper, a pulsed ruby laser is used to write gratings and the evolution of diffraction is monitored using a continuous wave laser, where the exposure mechanism is thermal and takes the material from an opaque to a transparent state.
Abstract: In this work the writing of diffraction gratings in liquid crystal polymer films is studied, where the exposure mechanism is thermal and takes the material from an opaque to a transparent state. A pulsed ruby laser is used to write gratings and the evolution of diffraction is monitored using a continuous wave laser. The resulting diffraction efficiency is compared with an analytic theory for a range of laser pulse energies and grating spacings. Results from the comparison are very good, and final efficiencies of around 5% are obtained, which is near the theoretical maximum for the material used.
01 Jan 1995
TL;DR: In this article, the front structures of strong shock waves in air were experimentally investigated by means of the laser Schlieren technique, and the detector response to a single pulse of a ruby laser was obtained.
Abstract: Front structures of strong shock waves in air were experimentally investigated by means of the laser Schlieren technique. Shocks in air at 13 Pa were generated with Mach numbers ranging from 2 to 34. The detector response to a single pulse of a ruby laser was obtained. This enabled the response correction of the Schlieren signals and the correction is greater at high Mach numbers (M > 16). Density profiles were obtained by integrating the corrected Schlieren signals. We present data of the reciprocal shock thickness for the investigated Mach numbers.
31 Mar 1995
TL;DR: In this paper, the dynamics of the laser-induced bubble is visualized by high speed photography and the pressure pulse signals from the bubble motion in the liquid nitrogen are measured under equilibrium or nonequilibrium conditions.
Abstract: This paper describes an investigation on the behavior of laser induced vapor bubble in cryogenic liquid nitrogen. The bubble is produced by the pulse ruby laser beam focused in the special cryostat. The dynamics of the laser-induced bubble is visualized by high speed photography. The pressure pulse signals from the bubble motion in the liquid nitrogen are measured under equilibrium or nonequilibrium conditions. Furthermore a numerical study is also performed on the dynamics of single spherical bubble in cryogenic liquid under the conditions corresponding to our experiment. Among the results the rapid growth of bubble and its rebounds have been visualized even in near-equilibrium conditions. Calculated results are compared with the experimented data.
TL;DR: In this article, the velocity of acoustic waves generated by photoacoustic effect using a pulsed ruby laser in benzene, chlorobenzene, carbontetrachloride and acetone in the pure form using delay time technique is reported.
TL;DR: In this paper, phase conjugation of radiation from a free-running ruby laser by a thermal nonlinearity of dye-activated nematics was demonstrated, and the conjugative coefficient was R ~ 100% near a phase transition to the isotropic state.
Abstract: Phase conjugation of radiation from a free-running ruby laser by a thermal nonlinearity of dye-activated nematics was demonstrated. The conjugation coefficient was R ~ 100% near a phase transition to the isotropic state. The temperature dependence of R was investigated theoretically and experimentally.