Showing papers on "Ruby laser published in 2006"
TL;DR: A new edge Thomson scattering diagnostic has been implemented at MAST to complement an existing high spatial resolution ruby laser system and the high time sampling core Nd:YAG system.
Abstract: A new edge Thomson scattering diagnostic has been implemented at MAST to complement an existing high spatial resolution ruby laser system and the high time sampling core Nd:YAG system The Nd:YAG system comprises of four independently controllable lasers Scattered light from these lasers is viewed at large scattering angle (153°) by a special optical arrangement in the new edge system The Nd:YAG lasers are viewed at 16 contiguous spatial locations separated by ∼1cm each, located at the plasma outboard pedestal and scrape-off layer region Here the use of a low f-number lens for the collection of a large solid angle of scattered light is particularly beneficial due to low plasma density (ne) The spectrum of scattered light is significantly broader at large scattering angles, allowing diagnosis of lower plasma temperatures (Te) while using the same spectrometer design as the core system The four Nd:YAG lasers follow two separate slightly offset (<1∕3 of a spatial channel) optical paths through the vesse
41 citations
TL;DR: Changes in structure or function of subcellular structures, sol-gel state, and growth rates were noted in single cells irradiated with microbeam laser.
Abstract: The development of the microbeam laser has made it possible to irradiate selected zones or subcellular structures within the cell. If sublethal pulses of irradiation are administered to parts of single cells, various changes in such cells can be observed. The reaction of biological material appears to be the denaturation of cellular proteins. Other changes also include coagulation, or the complete destruction, of a structure or zone that had been visible in the cell prior to irradiation. The object of our research has been to irradiate parts of single cells without causing the death of the cell. Changes in structure or function of subcellular structures, sol-gel state, and growth rates were noted. Amoebaproteus and Nitella axillaris were used in the present studies. Instrumentation
40 citations
TL;DR: In this paper, the photonic flame effect (PFE) was observed in three-dimensional synthetic opals (synthetic opals) placed on a Cu plate at the temperature of liquid nitrogen (77 K).
Abstract: We observed a new effect which we called the photonic flame effect (PFE). Several three-dimensional photonic crystals (synthetic opals) were posed on a Cu plate at the temperature of liquid nitrogen (77 K). The typical distance between the crystals was 1–5 cm. A long-continued optical luminescence was excited in one of the crystals by the ruby laser pulse. A visible luminescence appeared in the other crystals (not illuminated by the laser pulse), with a time delay with respect to the luminescence in the first crystal (illuminated by the laser pulse) being observed. We examined synthetic opal crystals and those filled with nonlinear liquids.
26 citations
TL;DR: Experimental observations of the effect of both neodymium and ruby laser radiation on the Cloudman S-91 Melanoma and the characteristics of the temperature gradient within the tumor at the moment of laser impact are discussed, as well as a theory that allows one to predict the probability of tumor destruction from laser radiation.
Abstract: Both neodymium and ruby laser radiation are capable of permanently destroying the highly malignant Cloudman S-91 melanoma, when implanted into the CDBA/ 2F, hybrid mouse. However, permanent tumor destruction is possible only when a variety of factors are fulfilled. The destructive effect of either source of laser energy was observed to be an immediate phenomenon in these laser-tumor experiments, and no evidence of progressive tumor regression was observed following exposure to laser radiation. When other tumor systems (the Lewis T240 sarcoma and the C3H/HEN Mouse Mammary adenocarcinoma not discussed in this paper) were studied, tumor destruction appeared to be an immediate phenomenon when it occurred. However, McGuff,' Klein,' and Helsper' have observed the phenomenon of progressive tumor destruction following laser radiation to other tumor systems. These observations suggest that an unidentified factor may be released or produced from irradiated tumors, which promotes the destruction of remaining viable tumor. This phenomenon has not been observed in any of our tumor experiments. This paper will discuss (1) experimental observations of the effect of both neodymium and ruby laser radiation on the Cloudman S-91 Melanoma; (2) the characteristics of the temperature gradient within the tumor at the moment of laser impact; (3) a theory that allows one to predict the probability of tumor destruction from laser radiation.
17 citations
TL;DR: The results are discussed and the advantages and disadvantages of the ruby laser as a source of energy to coagulate the choroid and retina are discussed.
Abstract: Preliminary reports1-* established that retinal coagulations could be effected using a laser source and suggested the desirability of its use clinically. Studies of photocoagulation at the Retina Foundation include an evaluation of laser as a retinal coagulator, on the basis of 9000 coagulations in pigmented rabbits and a limited number of humans. This report is a discussion of our results and of the advantages and disadvantages of the ruby laser as a source of energy to coagulate the choroid and retina.
9 citations
TL;DR: In this paper, a simulated infrared (IR) emission from a condensed dielectric medium under exposure to a giant pulse of a ruby laser was reported, where the angle of divergence of IR radiation was found to be 10−2 rad, while the conversion efficiency with respect to the pumping intensity depended on the type of molecular liquid.
Abstract: Stimulated infrared (IR) emission from a condensed dielectric medium under exposure to a giant pulse of a ruby laser is reported. This effect was predicted in the theoretical paper [1]. Experimental studies were carried out for a number of molecular liquids in two experimental geometries. In the first case (“in transmission” geometry) the propagation direction of the detected IR radiation coincided with that of the exciting radiation. In the second case IR radiation generated was detected in the opposite direction. The angle of divergence of IR radiation was found to be of 10−2 rad, while the conversion efficiency with respect to the pumping intensity depended on the type of molecular liquid and varied in the range of 0.05–0.6%. Possible microscopic mechanisms of generation of IR radiation under pumping of the dielectric medium with visible or ultraviolet (UV) radiation are analyzed.
7 citations
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TL;DR: In this article, the photonic flame effect (PFE) was observed in 3D opal crystals, where long-continued optical luminescence was excited in one of them by the ruby laser pulse.
Abstract: We observed new effect which we called photonic flame effect (PFE). Several 3-dimensional photonic crystals (artificial opals) were posed on Cu plate at the temperature of liquid nitrogen (77K). Typical distance between them was 1-5 centimeters. Long-continued optical luminescence was excited in one of them by the ruby laser pulse. Analogous visible luminescence manifesting time delay appeared in other samples of the crystals. Experiments were realized for opal crystals and for nanocomposites (opals filled with nonlinear liquids).
5 citations
TL;DR: In this paper, the wavefront reversal upon degenerate four-wave interaction in a CdF2 crystal with bistable In centers was investigated using a pulsed ruby laser as a pump source.
Abstract: The wavefront reversal upon degenerate four-wave interaction in a CdF2 crystal with bistable In centers is experimentally investigated using a pulsed ruby laser as a pump source. The reflectance and operating speed of the wavefront-conjugating mirror are measured and the quality of the reflected wave, as well as of the compensation of model phase distortions, is estimated. An operating speed of about 15 ns is obtained for such a mirror with a reflectance of up to 2% at room temperature. Compensation of model large-scale distortions yields a gain in the beam divergence of 20 and a quality of compensation of 1.05.
5 citations
TL;DR: In this article, a numerical simulation of melting and solidification processes induced in CdTe by nanosecond radiation of ruby laser and KrF excimer laser taking into account components diffusion in melt and their evaporation from the surface is carried out.
5 citations
TL;DR: In this paper, a plasma-deformation mechanism was proposed to explain the phenomenon of nanocluster array formation on a CdTe crystal surface under the action of a single nanosecond pulse of a ruby laser.
Abstract: A plasma-deformation mechanism is proposed which can explain the phenomenon of nanocluster array formation on a CdTe crystal surface under the action of a single nanosecond pulse of a ruby laser. The nonmonotonic dependence of the lateral size of nanoclusters on the laser radiation intensity predicted by the proposed model agrees with experiment.
5 citations
TL;DR: In this paper, the properties of Mn-doped GaAs layers grown by laser deposition were investigated with measurements of Hall effect and magneto-optical Kerr effect (MOKE).
TL;DR: In this article, the photosensitivity increase and the change of electrical properties of CdMnTe crystals which were photoexcited by pulsed ruby laser radiation (λ = 0.694 µm, tL = 20 ns) with pre-threshold energy density were observed.
Abstract: We observed the photosensitivity increase and the change of electrical properties of CdMnTe crystals which were photo-excited by pulsed ruby laser radiation (λ = 0.694 µm, tL = 20 ns) with pre-threshold energy density. Changes took place not only in the irradiated part of the samples investigated, but also outside. Analysis of the heat diffusion and the point defect diffusion has shown that these factors cannot be responsible for the laser effect of the long-range action. It could be connected with propagation of the surface elastic wave induced by pulsed laser irradiation. The possible mechanism of the optical excitation of the elastic wave in the semiconductor was analysed. It was determined that decreasing of the energy of the point defects generation takes place as a result of the laser processing.
TL;DR: In this paper, the authors investigated the role of the thermogradient effect in the reordering process of the mechanically polished surface of Si and Ge to single crystal and found that row of nanohills arises on the irradiated surface of Ge and Si single crystal after irradiation by Nd:YAG laser.
Abstract: Analysis of reordering of Ge amorphous surface by ruby laser; kinetics of the surface annealing after ion implantation using the optical reflectivity; occurrence of laser induced periodical structures; nanohills formation by Nd:YAG laser allowed us to resume common features for these process which belong to Thermogradient effect Experimental data on annealing of p-Si (111) and i-Ge (111) mechanically polished surfaces by Nd:YAG laser radiation using of optical microscopes and atomic force microscopes, optical reflectivity of He-Ne laser and the four-probe method confirmed the main role of Thermogradient effect in the reordering process of the mechanically polished surface of Si and Ge to single crystal It was found that row of nanohills arises on the irradiated surface of Ge and Si single crystal after irradiation by Nd:YAG Photoluminescence of nanohills row in visible range of spectra was established The photoluminescence of Ge and Si samples after irradiation by Nd:YAG laser is explained with quantum confinement effect on the top of nanohills - quasi quantum dots For explanation of this effect gathering of interstitial atoms at the irradiated surface is proposed
TL;DR: In this article, the photonic flame effect (PFE) and stimulated globular scattering (SGS) are discussed and a few seconds duration emission in blue-green spectral range under 20 ns ruby laser pulse excitation and simultaneous excitation of several spatially separated synthetic opal crystalls situated on the Cu plate are observed both in forward and backward directions.
Abstract: Novel nonlinear optical phenomena - photonic flame effect (PFE) and stimulated globular scattering (SGS) are discussed.PFE consisted in the appearance of the few seconds duration emission in blue-green spectral range under 20 ns ruby laser pulse excitation and simultaneous excitation of several spatially separated synthetic opal crystalls situated on the Cu plate. SGS was observed both in forward and backward directions. Spectral and energetical SGS characteristics were measured.
01 Jan 2006
TL;DR: The use of laser technology for incisional surgery, skin resurfacing and other applications is a rapidly advancing area within oculoplastic surgery.
Abstract: The use of laser technology for incisional surgery, skin resurfacing and other applications is a rapidly advancing area within oculoplastic surgery
The carbon dioxide (CO2) laser is frequently used for upper and lower eyelid blepharoplasty. Advantages of the CO2 laser for incisional surgery include reduced total intraoperative time, excellent hemostasis, and enhanced visualization of relevant anatomy
In many instances, laser skin resurfacing with the CO2 laser or the erbium:yttrium aluminum garnet (Er:YAG) laser is the treatment of choice over chemical peels and dermabrasion for photoaged skin
Non-ablative laser technologies are being used as alternative methods of improving photoaged skin with minimal healing time. These include the 580–590-nm fast-pulsed dye laser, the 595-nm pulsed dye laser, the 1,320-nm neodymium:YAG laser, and the 1,450-nm diode laser
Various non-laser technologies that also use electromagnetic radiation to heat tissue are being used for skin rejuvenation including broad spectrum light and radiofrequency
Vascular lesions can now be safely and effectively treated using a variety of lasers in the 488–638 nm range, or using broad spectrum light
Q-switched lasers, including the 532-nm fd Nd:YAG, the 755-nm alexandrite laser, and the 1,064-nm Nd:YAG laser are effective in removing tattoo pigments
In lacrimal surgery, the potassium titanyl phosphate (KTP) laser and holmium laser can be used to perform endonasal laser dacryocystorhinostomy and laser canaliculoplasty
Laser hair removal with the 694-nm ruby laser, the 755-nm alexandrite laser, the 810-nm diode laser, the long pulsed 1,064-nm Nd:YAG, or broad spectrum light can be successful in the reduction of pigmented hair follicles
The development of lasers with longer pulse widths and improved cooling devices allows treatment of darker skin types
09 Jan 2006
TL;DR: In this paper, Yu and Kolesnichenko demonstrated stable electrodeless MW discharge initiated by laser spark produced on the second harmonics of Nd:YAG laser with 15ns-pulse duration in air under the atmospheric pressure.
Abstract: The possibility of laser spark initiation of microwave discharge in quiescent air in wide range of air pressure has been investigated. For the first time the stable electrodeless MW discharge initiated by laser spark produced on the second harmonics of Nd:YAG laser with 15ns-pulse duration in air under the atmospheric pressure is realized. The MW breakdown thresholds under the variation of radiated laser energy and air pressure are measured. Stable breakdown at reduced MW field intensity is registered under a laser beam action. The effect of MW breakdown onset/stabilization in the presence of sub-breakdown intensity of laser beam is eliminated. The initiation ability of laser spark over MW pulse delay depends substantially upon air pressure and changes from 220μs under the normal conditions to more than 100ms under 70Torr. MW discharge development in the direction of sub-breakdown laser beam, but across MW beam is observed. This effect is analogues to laser triggering of DC spark. The possibility of Ruby laser spark initiation of 1μs pulse duration MW discharge in quiescent air under the atmospheric pressure was also demonstrated. The critical delays for MW radiation coupling with decaying laser plasma, exceeding 300μs were determined. The additional energy input due to MW energy deposition was recorded. Experiments with 400ps laser pulse duration on the first and second harmonics of Nd:YAG laser have shown that energy for laser spark creation is more than order of value less in comparison with nano-second pulse duration. The breakdown levels were attained under substantially lower levels of the applied energy – less than 1mJ for 532nm radiation and about 3mJ for 1064nm radiation. The shock waves, arising after picosecond-laser breakdown in air under the normal conditions, are registered by means of the Shlieren system. The effectiveness of transformations of laser pulse energy in an energy, inputted in the gas can be estimated as 0.3±0.1. Numerical investigation of laser plasma decay is carried out and regimes of MW filed interaction with decaying laser plasma are analyzed. Copyright © 2006 by Yu. F. Kolesnichenko. Published by the AIAA, Inc. with permission Introduction Beamed energy technique is attracting growing interest during last years. Progress in development of MW and laser facilities is opening new areas for their application and aerodynamics can also try to derive benefit from such scientific and technological progress. Laboratory experiments with beamed energy deposition in supersonic flow for flowfield modification have begun about 15 years ago. Since that time there were obtained results – experimental and theoretical – which revealed areas of effective energy deposition in front of moving supersonic body for drag reduction and local flow control [1-4]. Both MW and laser generation sources were tested in experiments [57]. Direct experimental evidence of high efficiency of MW plasmoids (filaments) for drag reduction was revealed in our investigations of MW discharge interaction with supersonic blunt bodies [5, 8-11]. Elongated in the direction of flow MW plasmoid about 17mm length and 4mm in diameter was created on the symmetry axis in front of detached shock wave of blunt body. Experimentally obtained drag reduction efficiency for AD body 30mm in diameter under M=2.1 flow conditions turned out about 30. This means that having deposited of about 30mJ in a specific MW plasmoid saved was 1J in body’s drag during interaction of plasmoid with AD body. Taking into account that only 10% of the absorbed energy are converting directly to gas heating, i.e. 3mJ, estimation of physical efficiency rises up to about 300. But the effect is very sensitive to the filament position and orientation. If MW plasmoid (filament) is disposed exactly on the axis of symmetry of a body then drag reduction is maximal. Shifting the filament off this position or its formation under some angle to the axis leads to sufficient diminishing of the effect magnitude down to even changing of its sign [8,9]. Exactly the demand of precise positioning of energy deposition region underlies the fact that application of MW for distant creation of discharge domains meets some difficulties. The most important among them – multi-peak structure of a focused MW radiation, which leads in the case of breakdown MW field to origination of number of plasmoids. As a rule, only one plasmoid is working effectively, others are either useless or even harmful. Multi-plasmoid structure of MW discharge leads also to a problem in managing of useful MW plasmoid position, as owing to inter-plasmoid interaction the discharge structure demonstrates some jitter (variation) in consequent realizations. So, there appears a need in some kind of stimulation of MW plasmoid directly at a defined point. 1 American Institute of Aeronautics and Astronautics 44th AIAA Aerospace Sciences Meeting and Exhibit 9 12 January 2006, Reno, Nevada AIAA 2006-792 Copyright © 2006 by Yu. Kolesnichenko. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.
18 Oct 2006
TL;DR: In this paper, the photonic flame effect (PFE) and stimulated globular scattering (SGS) were observed both in forward and backward direction in a pure opal crystal, consisting of the close-packed SiO 2 globules with diameter 200 nm and crystal with pores, filled with molecular liquid.
Abstract: Novel nonlinear optical effects - photonic flame effect (PFE) 1,2 and stimulated globular scattering (SGS) 3 - have been
discovered SGS was observed both in forward and backward direction Pure opal crystal, consisting of the close-packed
SiO 2 globules with diameter 200 nm, and crystal with pores, filled with molecular liquid, have been studied Two Stokes
components, shifted from the exciting light frequency by 04 - 06 cm -1 , have been observed in SGS Photonic flame
effect consisted in the appearance of the few seconds' duration emission in blue-green spectral range under 20 ns ruby
laser pulse excitation
TL;DR: In this article, a pulsed ruby laser was used in an unstable environment to overcome the high stability requirements when a hologram is recorded, and images were recorded for the purpose of measurement applied to non-destructive inspection (NDI) and medical applications.
Abstract: A pulsed ruby laser was used in an unstable environment to overcome the high stability requirements when a hologram is recorded. The images were recorded for the purpose of measurement applied to non-destructive inspection (NDI) and medical applications. High-resolution photographic film or plates coupled with wet processing was employed as the recording material, but other recording materials are considered. The paper also explores the potential of electronic and digitized processes currently being developed.
09 Feb 2006
TL;DR: In this article, the results of experimental investigation of parameters of laser-formed periodic nanostructuring of metal film by means of intracavity processing in the resonator of ruby laser with laser radiation wavelength 0.69 micrometers were shown.
Abstract: There are shown the results of experimental investigation of parameters of laser-formed periodic nanostructuring of metal film by means of intracavity processing in the resonator of ruby laser with laser radiation wavelength 0.69 micrometers. AFM-treatment of formed nanostructures profiles has shown the possibility to form multiple periodic structures with characteristic sizes less 200 nanometers during one laser pulse.