Showing papers on "Ruby laser published in 1997"
TL;DR: Selective melanin‐based photothermolysis with a free running pulsed ruby laser seems to be a promising, noninvasive technique for long‐term hair removal.
Abstract: backgroundLaser-assisted hair removal with the long pulsed ruby laser is a promising new technique based on selectively targeting melanin in hair follicles.objectiveThe purpose of this study was to evaluate the efficacy and safety of the long pulsed ruby laser (EpiTouch) for hair removal.methodsThe
152 citations
TL;DR: Both the superficial and the deep portions of the congenital melanocytic nevi were affected by the 2 lasers, as evidenced by macroscopic inspection as well as microscopic evaluation, and the Q-switched laser treatment did not destroy all nevomelanocytes, particularly in the deeper, less pigmented portion of the lesions.
Abstract: Background: Laser irradiation of congenital melanocytic nevi is a controversial treatment. Recurrence of lesions after laser treatment appears to be the rule, and the effects of laser irradiation on cellular biological behavior and the possible mutagenic responses of nevomelanocytes that have received nonlethal doses of irradiation are still unclear. Without treatment, there is an increased potential for malignant degeneration over a lifetime. The purpose of this study was to examine the effects of Q-switched lasers on congenital nevi and to explain the mechanism(s) behind the response of the nevi to laser treatment. Five congenital nevi were divided into 3 equal parts: 1 part was treated with the Q-switched ruby laser at a wavelength of 694 nm, 1 part was treated with the Q-switched neodymium:YAG laser at a wavelength of 1064 nm, and 1 part was left untreated to serve as control. At intervals ranging from 3 days to 3 months after laser irradiation, the lesions were excised and evaluated by routine staining. This clinical study was conducted entirely at the Massachusetts General Hospital Dermatology Laser Center, Boston, Mass. Observations: Both the superficial and the deep protions of the congenital melanocytic nevi were affected by the 2 lasers, as evidenced by macroscopic inspection as well as microscopic evaluation. However, the Q-switched laser treatment did not destroy all nevomelanocytes, particularly in the deeper, less pigmented portions of the lesions. Conclusions: Both the Q-switched ruby laser and the neodymium:YAG laser often removed only the superficial portion of the congenital melanocytic nevi. The Q-switched ruby laser (694 nm) appeared to be more effective in removing nevomelanocytes than the Q-switched neodymium:YAG laser (1064 nm). Arch Dermatol. 1997;133:349-353
111 citations
TL;DR: New, long-pulsed pigment-specific lasers may prove to further enhance the clinical results obtained in resistant pigmented lesions and other conditions.
92 citations
TL;DR: The QSR laser was shown to be the most effective in removing pigment in the three cases that received both QSR and QSYAG laser treatment, and can be treated effectively with the Q‐switched ruby laser.
Abstract: Background Q-switched lasers have shown to be effective in the removal of unwanted cutaneous pigmentation. Benign cutaneous pigmented lesions represent a heterogeneous group. Nevus spilus is a relatively uncommon pigmented lesion characterized by dark, hyperpigmented dots scattered over a tan-colored macule. Objective A cohort of patients with nevus spilus was studied to determine the effects of Q-switched ruby and Q-switched Nd:YAG laser treatment on clearance of pigment and to evaluate potential side effects. Methods Six patients with nevus spilus were treated with the Q-switched ruby laser (QSR). In addition, three lesions received a test treatment with the Q-switched Nd:YAG (QSYAG) laser at 532 or 1064 nm. The results of treatment were documented during follow up visits. Results Most lesions showed a near-complete or complete response to laser treatment. In one case partial hyperpigmentation occurred after treatment and in one case no follow-up could be obtained. In the three cases that received both QSR and QSYAG laser treatment, the QSR laser was shown to be the most effective in removing pigment. Conclusion Nevus spilus can be treated effectively with the Q-switched ruby laser.
60 citations
TL;DR: In this paper, the lasing performance of polymers poly(2,5-dioctadecyloxy-paraphenylene-ethynylene-co-2.5-thienyl) (OPT) and poly( 2,5dioxane-paraphhenyl-paramphenylene)-co-pyridinyl (OPP) in organic solvents was studied.
Abstract: The lasing performance of the polymers poly(2,5-dioctadecyloxy-paraphenylene-ethynylene-co-2,5-thienyl) (OPT) and poly(2,5-dioctadecyloxy-paraphenylene-ethynylene-co-2,5-pyridinyl) (OPP) in organic solvents was studied. A two-mirror resonator was transversally pumped using single pulses of the second harmonic of a mode-locked ruby laser. OPT in tetrahydrofuran lased in the region from 480 nm to 525nm and OPP in tetrahydrofuran showed laser action in the region from 460 nm to 490nm. The polymer solutions are characterized by absorption and fluorescence spectroscopic analysis. Effective stimulated emission cross-sections are reported. High excited-state absorption cross-sections and residual ground-state absorption reduce the lasing efficiency.
34 citations
TL;DR: In this paper, a double exposure interferometer using a Bi12GeO20 crystal as the holographic medium is presented, where the simultaneous acquisition of two phase shifted interferograms allows real-time quantitative measurement of displacements of a scattering object.
32 citations
TL;DR: A gamma-ray laser has been proposed to stimulate coherent emission of radiation at wavelengths below 1 A from excited states of nuclei as discussed by the authors, however, the difficulties in realizing such a device were considered insurmountable when the first cycle of study ended in1981.
Abstract: A gamma-ray laser would stimulate coherent emission of radiation at wavelengths below 1 A from excited states of nuclei. However, the difficulties in realizing such a device were considered insurmountable when the first cycle of study ended in1981. Since then, research on the feasibility of a gamma-ray laser has taken on a completely new character. A nuclear analog of the ruby laser has been proposed and many of the component steps for pumping the nuclei have been demonstrated experimentally. A quantitative model based upon the new data and the concepts of this decade shows the gamma-ray laser to be feasible if some real isotope has its properties sufficiently close to the ideals. The greatest positive impact has come from the discovery of giant resonances for pumping nuclei with photons that greatly reduce the levels of input power needed. Most recently, attention has been focused upon efforts to demonstrate prelasing levels of fluorescence from simulation nuclides and actual gamma-ray laser candidates. Problems being addressed are the acquisition of macroscopic samples of the best nuclei for testing and the demonstration of appropriate instrumentation.
22 citations
13 citations
TL;DR: In this article, a high-energy, high contrast ultrashot laser pulses have been generated by amplification of a Raman-shifted ruby laser radiation in a Nd:glass amplifier.
10 citations
TL;DR: In this article, a short laser pulse from a 1 J ruby laser is focused at a steel plate, and the effect will be that the material surface at the impact point becomes very rapidly heated.
Abstract: A short laser pulse from a 1 J ruby laser is focused at a steel plate. The effect will be that the material surface at the impact point becomes very rapidly heated. Metal vapour leaves the surface at a very high velocity. That is, both a mechanical impulse and local thermal energy are transferred to the plate. The mechanical impulse creates propagating bending waves in the plate, which in turn creates transient sound waves in the surrounding air. The heated spot at the plate surface creates thermal stresses in the plate which g\ve rise to an out-of-plane deformation of the plate. This deformation is added up to the propagating bending waves. These effects are studied in experiments using pulsed holographic interferometry.
8 citations
TL;DR: In this article, a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed, where light from a double pulsed ruby laser (pulse separation: 10−800 μs, max. 2×12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator for spectral analysis.
Abstract: In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10–800 μs, max. 2×12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator for spectral analysis. The spectrally resolved light is recorded by two ICCD detectors. Simulations show that the system sensitivity will be such that electron temperatures in the range of 100 eV–7 keV can be determined with an accuracy as good as 2%–3% for electron densities of 1020 m−3, with a spatial resolution down to 2.6 mm. With this diagnostic the dynamics of small scale structures in the electron temperature profile will be studied.
TL;DR: In this article, the authors identified twenty five elements whose resonance lines overlap the emission lines of high-power pulsed ultraviolet gas lasers or lie in the immediate vicinity of them, so that the mechanism laser ionization based on resonance saturation (LIBORS) can be used to ionize the vapor of these elements.
Abstract: An identification is made of twenty five elements whose resonance lines overlap the emission lines of high-power pulsed ultraviolet gas lasers or lie in the immediate vicinity of them, so that the mechanism laser ionization based on resonance saturation (LIBORS) can be used to ionize the vapor of these elements. Resonance transitions of atoms and ions excited by the same laser (by krypton fluoride and xenon fluoride lasers, respectively) are observed for tantalum and uranium. It ishas been suggested that these elements may be used as “catalysts” for “ catalytic” resonance ionization (CATRION) of dense multicomponent gas mixtures. Experiments have been carried out to study the krypton fluoride laser irradiation of expanding vapor clouds of different elemental composition, created by the evaporation of targets with a ruby laser. Photographs obtained with an image converter, measurements of the refractive index gradient from the deflection of the laser beam, as well as probe and spectroscopic measurements indicate that the clouds undergo photoresonant ionization if they contain tantalum vapor but that the laser radiation has no influence otherwise.
TL;DR: In this paper, a laser triggered intensified charge coupled device (CCD) with 80 mm aperture, two stages of intensification, and 80 ns gating was developed for application to a ruby laser Thomson scattering system.
Abstract: For application to a ruby laser Thomson scattering system, we have developed a laser triggered intensified charge coupled device (CCD) with 80 mm aperture, two stages of intensification, and 80 ns gating. To improve the dynamic range, the CCD is cooled and read out slowly (1 s). To obtain a good extinction ratio (>1.1×107), the zoom electrode of the first intensifier is gated using a ∼10 kV laser triggered spark gap. The stability of this spark gap has been greatly improved by frequency doubling the laser trigger light.
TL;DR: Frequency doubling in potassium titanyl phosphate generate tunable red-yellow light in laser oscillation of Cr:forsterite with ruby laser pumping to the lowest-lying levels of the (3)T(1) band.
Abstract: Laser oscillation of Cr:forsterite was obtained with ruby laser pumping
to the lowest-lying levels of
the 3T1 band in Cr4+. Pump polarization effects, temporal response, and broadband 220-nm tuning are reported. Frequency doubling in
potassium titanyl phosphate generate tunable red–yellow light. This
unconventional excitation scheme is of interest for potential high-energy
output and for direct diode pumping.
TL;DR: In this article, the first systematic measurements of the electron temperature (Te) spatial profile have been obtained in the reversed field pinch experiment RFX with a single pulse Thomson scattering (TS) diagnostic.
Abstract: The first systematic measurements of the electron temperature (Te) spatial profile have been obtained in the reversed field pinch experiment RFX with a single pulse Thomson scattering (TS) diagnostic. Scattered light from a ruby laser pulse (E⩽15 J, Δt=30 ns) is collected through three objectives from 10 positions along a diameter in the plasma equatorial plane, with a spatial resolution of 2.5 cm. Plasma discharges with current in the range 700–900 kA have been investigated finding evidence of a quite flat Te profile. Data dispersion significantly greater than experimental uncertainties provides an indication of remarkable plasma fluctuations. Results are in good agreement with Te measurements from other single chord spectroscopic diagnostics (SiLi detector and SXR double filter), showing a reliable operation down to an electron density ne=3×1019 m−3. Integration of this apparatus with a ND:YLF laser system for multipulse Thomson scattering measurements, sharing the same input optics, is under way.
Journal Article•
TL;DR: The Q-switched ruby laser with an emission wavelength of 694 nm and a pulse duration of 25 ns or 40 ns selectively destroys pigmented cells when treating tattoos and benign cutaneous pigmented lesions very successfully.
Abstract: The Q-switched ruby laser with an emission wavelength of 694 nm and a pulse duration of 25 ns or 40 ns selectively destroys pigmented cells. When treating tattoos and benign cutaneous pigmented lesions, very good therapeutic results can be achieved. Five patients with Nevus of Ota are presented, whose lesions were treated with the Q-switched ruby laser very successfully.
23 Jan 1997-Plastic surgical nursing : official journal of the American Society of Plastic and Reconstructive Surgical Nurses
TL;DR: Hair removal with the ruby laser is one of the newest uses of laser technology, and the laser seeks melanin in the hair shaft, and melanin content is highest during the growth phase of the hair follicle.
Abstract: Hair removal with the ruby laser is one of the newest uses of laser technology. The laser seeks melanin in the hair shaft, and melanin content is highest during the growth phase of the hair follicle. Nursing care focuses on preparing the patient for the procedure, maintaining a safe operative environment, and teaching the patient skin care after the laser therapy.
28 May 1997
TL;DR: In this article, two types of single mode lasers are described: high power iodine laser (equals 1.315 micrometers ) of about 2 kW power and impulse duration of about 5 - 10 microsecond(s).
Abstract: The power of laser emission is very important for Doppler velocimeters. Doppler velocimeters with high power laser allow us to investigate structure of shock and detonation waves in a nanosecond region and to perform multichannel diagnostics. Two types of single mode lasers are described in this work. High power iodine laser (equals 1.315 micrometers ) of about 2 kW power and impulse duration of about 5 - 10 microsecond(s) . Ruby laser of 150 W power and of 200 microsecond(s) impulse duration. The width of spectral emission is 3.10-3 cm-1 for both lasers. Two interferometer systems, based on these lasers were made: Fabry-Perot interferometer and ORVIS. Also this paper describes the examples of application of interferometer systems with powerful lasers.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
01 Jan 1997
TL;DR: In this article, the basic principles of laser operation are described, and some of the terminology encountered in the laser work is defined, as well as the complete range of the wavelengths covered by operating lasers runs from 0.01 to 1000 μm.
Abstract: This chapter provides fundamental information about lasers. It describes the basic principles of laser operation, and defines some of the terminology encountered in the laser work. The light emitted by a laser is the electromagnetic radiation. It includes a continuous range of many different types of radiant energy. The complete range of the wavelengths covered by operating lasers runs from 0.01 to 1000 μm. The region in which useful devices for industrial applications operate is about 0.2 to 10 μm. Lasers can be fabricated using a variety of materials as the active medium. Each such material has its own distinctive wavelength. Some of these materials occur in relation to each other, and to the electromagnetic spectrum as a whole. Few of these useful lasers include: the CO 2 laser, the neodymium glass laser, the aluminum gallium arsenide laser, the ruby laser, and the helium–neon laser. The laser beams are often linearly polarized. Inserting a polarizer in the beam path can test the polarization of a beam. Polarization effects are used to eliminate losses when light passes from vacuum, or a gas into a transparent solid.
TL;DR: In this article, a multipass/multipulse Thomson scattering system has been implemented on CDX-U in collaboration with the Ioffe Institute, St Petersburg, Russia.
Abstract: A multipass/multipulse Thomson scattering system has been implemented on CDX-U in collaboration with the Ioffe Institute, St. Petersburg. The system consists of a low energy (1.5– 2.5 J), passively Q-switched ruby laser, and a multipass optical cavity enclosing the plasma. Multiple reflections of the beam within the cavity increase by about an order of magnitude the number of scattered photons, allowing temperature density to be measured with good accuracy even at very low plasma density. By feeding the returned beam back into the laser, the system can deliver several pulses over a 1 ms period. However, the experiments on CDX-U show that a mechanical shock wave reaching the multipass system affects the feedback and laser output per pulse drops significantly. Therefore we operate the system by fine tuning the laser cavity, so that output is practically independent of feedback from multipass cavity. Also, by optimizing the transmission of the passive Q-switch and the pumping power, we obtain that laser outp...
TL;DR: In this paper, a report is given of changes in the structure of magnetic domains in fine-grained silicon steel (3% Si) observed experimentally with a free-running ruby laser.
Abstract: A report is given of changes in the structure of magnetic domains in fine-grained silicon steel (3% Si) observed experimentally with a free-running ruby laser. These changes are probably caused by the magnetoelastic effect since the temperature of the surface layers, calculated by mathematical simulation, is below the Curie temperature.