Argon lasers are the most frequently used laser source for retinal photocoagulation. These are expensive, bulky and low-efficiency devices. In contrast, diode semiconductor lasers have a number of characteristics that make them attractive for medical application: compact size, high electrical-to-optical efficiency, and long operating lifetime. Comparable irradiance lesions (about 120 Wcm2), ophthalmoscopically similar to those obtained therapeutically in humans, were obtained by a diode and an argon laser. Twenty-four hours after the treatment, a study of these lesions was made by light and electron microscopy. Argon irradiations resulted in damage to both the inner and the outer retinal layers, while the diode laser radiation produced damage to the outer retina and choroid. A sufficient diode laser light passed into the choroid to induce small vessel occlusions and/or edema. The histological characteristics of the lesions produced by the two lasers suggest the use of the diode lasers, as well as argon lasers, in the treatment of retinal and subretinal pathologies.
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Eur J Paediatr Dent
October 2024
Dentistry and Maxillofacial Surgery Section, Department of Surgery, Dentistry, Pediatrics and Gy-necology, University of Verona, Verona, Italy.
Aim: This systematic review aimed to evaluate, by means of statistical comparison between selected studies, the effectiveness of laser irradiation on dental erosion applied alone or in combination with anti-erosive agents (fluoride, Acidulated phosphate fluoride APF and CPP-amorphous calcium fluoride phosphate CPP-ACFP), through optical profilometry and microhardness measurement.
Methods: The searching strategy was conducted according to the International PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, to answer research ques-tions regarding the effectiveness of lasers used in the context of dental erosion (such as Nd:YAG, CO2, Er:YAG, Er,Cr:YSGG, Diode, and Argon Ion lasers). A comprehensive and unrestricted sys-tematic searching was performed using the electronic databases of PubMed and Cochrane Library, for all articles published up to the end of January 2023.
Rev Sci Instrum
July 2024
Naval Research Laboratory, Washington, District of Columbia 20375, USA.
The use of an electron beam to pump an excimer laser has the advantage of being readily scalable to higher laser energies at high efficiency. Typically, a pulsed power driver generates the electron beam in a vacuum diode that consists of an electron emitter and a thin anode foil that holds the vacuum against the atmospheric-pressure laser gas. Even a miniscule leak in the anode foil can lead to an electrical breakdown in the vacuum diode, resulting in the destruction of the foil and evidence of the failure mechanism.
View Article and Find Full Text PDFRev Sci Instrum
July 2024
Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada.
Laser-Induced Fluorescence (LIF) spectroscopy is an essential tool for probing ion and atom velocity distribution functions (VDFs) in complex plasmas. VDFs carry information about the kinetic properties of species that is critical for plasma characterization. Accurate interpretation of these functions is challenging due to factors such as multicomponent distributions, broadening effects, and background emissions.
View Article and Find Full Text PDFDent J (Basel)
May 2024
Department of Dental Prosthetics, Medical University of Gdańsk, Elizy Orzeszkowej 18, 80-208 Gdańsk, Poland.
Laser, an acronym for Light Amplification by Stimulated Emission of Radiation, is a powerful tool with diverse applications in modern dentistry. It emits monochromatic, coherent light resulting from photon-induced chain reactions. Available dental lasers include diode, argon, Er,Cr:YSGG, Er:YAG, Nd:YAG, and CO.
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May 2024
Department of Aeronautics and Astronautics, Kyoto University, Kyoto 615-8540, Japan.
Controlling the ion velocity in an ion sheath by applying an alternating current (AC) voltage to an electrode and/or a substrate is critical in plasma material processes. To externally control the velocity distribution of incident ions on a substrate, the application of tailored-waveform AC voltages instead of sinusoidal voltages has garnered interest in recent years. In this study, to investigate temporal changes in ion-velocity distributions, we developed a time-resolved laser-induced fluorescence spectroscopy (LIF) system using a continuous-wave diode laser as an excitation-laser source.
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