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YAG laser

Won Seon Koh, Jeong Eun Kim, Young Suck Ro, Joo Yeon Ko
BACKGROUND: Despite various treatments attempts, no prospective studies have compared the different therapeutic modalities for treatment of idiopathic guttate hypomelanosis (IGH). This study aimed to compare the efficacy of CO2 fractional laser (CO₂FL), Er:YAG fractional laser (EYFL), and 0.025% topical tretinoin for treating IGH. MATERIALS AND METHODS: A total of 122 lesions were analyzed from 18 patients (mean age, 70.00 ± 20.00 years). Treatment outcome evaluations included the visual analog scale (VAS) to assess lesion severity, investigator's global assessment (IGA) to assess the extent of improvement, and patient's satisfaction score (PSS)...
March 16, 2018: Journal of Cosmetic and Laser Therapy: Official Publication of the European Society for Laser Dermatology
Pinar Cevik, Oguz Eraslan, Kursat Eser, Suleyman Tekeli
PURPOSE: The aim of this study was to evaluate the effect of six different surface conditioning methods on the shear bond strength of ceramic brackets bonded to feldspathic porcelain. MATERIALS AND METHODS: A total of 60 feldspathic porcelain disks were fabricated and divided into six subgroups including 10 specimens in each. Specimens were first treated one of the following surface conditioning methods, namely, 37% phosphoric acid (G-H3PO4), 9.4% hydrofluoric acid (G-HF), grinding with diamond burs (G-Grinding), Nd:YAG laser (G-Nd:YAG), Airborne-particle abrasion (G-Abrasion)...
March 2018: International Journal of Artificial Organs
Tanya Moutray, Jennifer R Evans, Noemi Lois, David J Armstrong, Tunde Peto, Augusto Azuara-Blanco
BACKGROUND: Diabetic retinopathy (DR) is a chronic progressive disease of the retinal microvasculature associated with prolonged hyperglycaemia. Proliferative DR (PDR) is a sight-threatening complication of DR and is characterised by the development of abnormal new vessels in the retina, optic nerve head or anterior segment of the eye. Argon laser photocoagulation has been the gold standard for the treatment of PDR for many years, using regimens evaluated by the Early Treatment of Diabetic Retinopathy Study (ETDRS)...
March 15, 2018: Cochrane Database of Systematic Reviews
Haizhou Huang, Jianhong Huang, Yan Ge, Hui Zheng, Wen Weng, Hongchun Wu, Wenxiong Lin
We realize Ho laser operation in a composite Tm/Ho:YAG gain medium for the first time, to the best of our knowledge, which was integrated via diffusion bonding the Tm-doped and Ho-doped crystals into a single bulk structure. A maximum output power around 6 W was obtained with a slope efficiency of 40.1% and conversion efficiency (CE) of 33.6% from the absorbed 785 nm laser diode to 2122 nm Ho laser, which is comparable with CE in 1.9 μm LD pumped Ho lasers. Such a scheme is demonstrated to be another valid way for Ho laser generation here, which is of significance to be adopted in other host media or waveguide structures for an assessable, compact, and efficient Ho laser...
March 15, 2018: Optics Letters
Florent Starecki, Nora Abdellaoui, Alain Braud, Jean-Louis Doualan, Catherine Boussard-Plédel, Bruno Bureau, Patrice Camy, Virginie Nazabal
In this Letter, we report for the first time, to the best of our knowledge, on an emission at 8 μm from Tb3+ -doped Ga5 Ge20 Sb10 Se65 chalcogenide fibers with doping levels at 1000 ppm and 500 ppm. These fibers were drawn following conventional melt-quenching methods and pumped at 2.05 μm using a Tm3+ : YAG laser. The spectroscopic properties of the emitting F4 7 manifold are investigated to rule out any parasitic signal mimicking the real Tb3+ 8 μm emission. Time-resolved spectroscopic experiments are presented to build a comprehensive study of this 8 μm fluorescence recorded with a clear signal-to-noise ratio...
March 15, 2018: Optics Letters
Samuel B Penwell, Lukas Whaley-Mayda, Andrei Tokmakoff
We present the design and characterization of a tunable mid-IR optical parametric amplifier (OPA) with a 1 MHz 1033 nm fiber laser pump source. The OPA generates >10  nJ/pulse tunable from 3-7.5 μm with 85-165  cm-1 bandwidth and 140-540 fs pulse durations. The design utilizes a single stage of collinear, Type I amplification in lithium gallium sulfide (LGS) seeded by the near-IR portion of a super-continuum (SC) generated in yttrium aluminum garnet (YAG). The resulting mid-IR idler beam is isolated as the output...
March 15, 2018: Optics Letters
V A Shaimova, T B Shaimov, R B Shaimov, A Yu Galin, Zh A Goloshchapova, P K Ryzhkov, A V Fomin
PURPOSE: To develop methods for evaluating effectiveness of YAG-laser vitreolysis of vitreous floaters. MATERIAL AND METHODS: The study included 144 patients (173 eyes) who had underwent YAG-laser vitreolysis and were under observation from 01.09.16 to 31.01.18. The patients were 34 to 86 years old (mean age 62.7±10.2 years), 28 (19.4%) patients were male, 116 (80.6%) - female. All patients underwent standard and additional examination: ultrasonography (Accutome B-scan plus, U...
2018: Vestnik Oftalmologii
Jun Ma, Bin Chen, Dong Li, Yue Zhang, Zhaoxia Ying
Port-wine stain (PWS) birthmark is a congenital microvascular malformation of the skin. A 1064-nm Nd:YAG laser can achieve a deeper treatment, but the weak absorption by blood limits its clinical application. Multiple laser pulses (MLPs) are a potential solution to enhance the curative effect of a Nd:YAG laser. To reduce the pulse number (pn ) required for the thermal destruction of the blood vessel, the effect of glucose in conjunction with MLP was investigated. In vivo experiments were performed on a dorsal skin chamber model...
March 14, 2018: Lasers in Medical Science
Xue Chen, Xiaohui Li, Sibo Yang, Xin Yu, Aichun Liu
Lymphoma is a significant cancer that affects the human lymphatic and hematopoietic systems. In this work, discrimination of lymphoma using laser-induced breakdown spectroscopy (LIBS) conducted on whole blood samples is presented. The whole blood samples collected from lymphoma patients and healthy controls are deposited onto standard quantitative filter papers and ablated with a 1064 nm Q-switched Nd:YAG laser. 16 atomic and ionic emission lines of calcium (Ca), iron (Fe), magnesium (Mg), potassium (K) and sodium (Na) are selected to discriminate the cancer disease...
March 1, 2018: Biomedical Optics Express
Toru Takagi, Akira Aoki, Shizuko Ichinose, Yoichi Taniguchi, Noriko Tachikawa, Takeshi Shinoki, Walter Meinzer, Anton Sculean, Yuichi Izumi
BACKGROUND: Recently, the occurrence of peri-implantitis has been increasing. However, a suitable method to debride the contaminated surface of titanium implants has not been established. The aim of this study was to investigate the morphological changes of the microstructured fixture surface after erbium laser irradiation, and to clarify the effects of the erbium lasers when used to remove calcified deposits from implant fixture surfaces. METHODS: In experiment 1, sandblasted, large grit, acid etched surface implants were treated with Er:YAG laser or Er,Cr:YSGG laser at 30-60 mJ/pulse and 20 Hz with water spray...
March 13, 2018: Journal of Periodontology
Hannes Petersen, Alexandra Gliese, Yannick Stober, Stephanie Maier, Nils-Owe Hansen, Sebastian Kruber, Dennis Eggert, Miklós Tóth, Tobias Gosau, Hartmut Schlüter, Klaus Püschel, Udo Schumacher, Robert John Dwayne Miller, Adrian Münscher, Carsten Dalchow
OBJECTIVE: Using a contact-free laser technique for stapedotomy reduces the risk of mechanical damage of the stapes footplate. However, the risk of inner ear dysfunction due to thermal, acoustic, or direct damage has still not been solved. The objective of this study was to describe the first experiences in footplate perforation in cadaver tissue performed by the novel Picosecond-Infrared-Laser (PIRL), allowing a tissue preserving ablation. PATIENTS AND INTERVENTION: Three human cadaver stapes were perforated using a fiber-coupled PIRL...
April 2018: Otology & Neurotology
Xiaoming Chen, Yanhua Lu, Hao Hu, Lixin Tong, Lei Zhang, Yi Yu, Juntao Wang, Huaijin Ren, Liu Xu
We present investigations into a narrow-linewidth, quasi-continuous-wave pulsed all-solid-state amplified spontaneous emission (ASE) source by use of a novel multiple-pass zigzag slab amplifier. The SE fluorescence emitted from a Nd:YAG slab active medium acts as the seed and is amplified back and forth 8 times through the same slab. Thanks to the angular multiplexing nature of the zigzag slab, high-intensity 1064-nm ASE output can be produced without unwanted self-lasing in this configuration. Experimentally, the output energy, optical conversion efficiency, pulse dynamics, spectral property, and beam quality of the ASE source are studied when the Nd:YAG slab end-pumped by two high-brightness laser diode arrays...
March 5, 2018: Optics Express
Han Chi, Kristian A Dehne, Cory M Baumgarten, Hanchen Wang, Liang Yin, Brendan A Reagan, Jorge J Rocca
Heat generation is a key obstacle to scaling high energy solid-state lasers to the multi-kilowatt average powers required for several key applications. We demonstrate an accurate, in situ, noninvasive optical technique to that makes three-dimensional (3-D) temperature maps within cryogenic amplifiers operating at high average power. The temperature is determined by analyzing the fluorescence spectra with a neural network function. The accuracy of the technique relies on a calibration that does not depend on simulations...
March 5, 2018: Optics Express
Sun Young Choi, Thomas Calmano, Fabian Rotermund, Christian Kränkel
We demonstrate GHz-repetition rate mode-locked operation of a femtosecond-laser-inscribed Yb:YAG channel waveguide laser using single-walled carbon nanotube saturable absorber mirror (SWCNT-SAM). A 6.3-mm-long, type II Yb:YAG waveguide laser with an extended cavity configuration delivers mode-locked picosecond (ps) pulses at GHz repetition rates. The dispersion of the laser cavity is compensated by the combination of a multi-functional output coupler and the Gires-Tournois interferometer (GTI) effect arising from an air-gap between the facet of the waveguide and the output coupler...
March 5, 2018: Optics Express
Bruno Henriques, Douglas Fabris, Júlio C M Souza, Filipe S Silva, Óscar Carvalho, Márcio C Fredel, Joana Mesquita-Guimarães
OBJECTIVES: The aim of this study was to evaluate the effect of laser surface structuring on the bond strength of feldspar-based porcelain to zirconia, as compared to conventional sandblasting treatment. MATERIALS AND METHODS: Thirty cylindrical zirconia substrates, previously sintered, were divided in three groups according to the type of surface conditioning: 1) sandblasting with 50 µm Al2 O3 ; 2) laser structuring (Ø25 µm holes); and 3) laser structuring (Ø50 µm holes)...
February 27, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Donato Girolamo, Huan-Yu Chang, Fuh-Gwo Yuan
A fully non-contact laser-based nondestructive inspection (NDI) system is developed to detect and visualize damage in structures. The study focuses on the size quantification and characterization of a barely visible impact damage (BVID) in a honeycomb composite panel. The hardware consists of a Q-switched Nd:YAG pulse laser that probes the panel by generating broadband guided waves via thermo-elastic expansion. The laser, in combination with a set of galvano-mirrors is used to raster scan over a two-dimensional surface covering the damaged region of an impacted quasi-isotropic [60/0/-60]s honeycomb composite panel...
February 16, 2018: Ultrasonics
Jiasai Ma, Wenguang Jiang, Chuanhe Shen, Shanfu Yuan
A MoSe2 nanosheets-based saturable absorber (SA) was fabricated successfully by the liquid-phase exfoliation method. A passively Q-switched crystalline Yb:YAG laser was realized with the MoSe2 SA inserted inside the cavity. The shortest pulses at a wavelength of 1049 nm with a duration of 250 ns, maximum repetition rate of 181 kHz, and an average output power of 158 mW were emitted, corresponding to a maximum pulse energy of 0.87 μJ. To the best of our knowledge, this is the first experimental demonstration of the nonlinear absorption property of MoSe2 nanoplatelets in a crystalline Yb-doped solid-state laser, which also proves the great potential of the MoSe2 SA as an optical modulator in the 1 μm spectral region...
March 10, 2018: Applied Optics
Morgan O'Neil, Nicholas A Niemiec, Andrew R Demko, Eric L Petersen, Waruna D Kulatilaka
Numerous metals and metal compounds are often added to propellants and explosives to tailor their properties such as heat release rate and specific impulse. When these materials combust, these metals can be released into the air, causing adverse health effects such as pulmonary and cardiovascular disease, particulate-matter-induced allergies, and cancer. Hence, robust, field-deployable methods are needed to detect and quantify these suspended metallic particles in air, identify their sources, and develop mitigation strategies...
March 10, 2018: Applied Optics
Yan Liu, Weihui Zeng, Di Li, Weihua Wang, Feng Liu
BACKGROUND: Nevus of Ota can be treated successfully using the Q-switched (QS) laser; but few studies are long-term retrospective of the efficacy and influencing factor, studies on the recurrence is even less. PURPOSE: Retrospective analysis of the clinical characteristics and recurrence of QS Nd:YAG laser treatment of nevus of Ota in 224 Chinese patients at Laser Cosmetology Center of Department of Dermatology, the Second Hospital, Xi'an Jiaotong University. METHODS: The data of 224 patients with nevus of Ota were analyzed retrospectively, which included the correlation among lesion color, treatment sessions, gender, age, lesion types and effect, and all patients were followed up for 2-10 years...
March 9, 2018: Journal of Cosmetic and Laser Therapy: Official Publication of the European Society for Laser Dermatology
Claudio I Perez, Sunee Chansangpetch, Yen C Hsia, Shan C Lin
Purpose: To report the first case of Neodymium Yttrium Aluminum Garnet ( Nd:YAG) laser use to recanalize a CyPass occluded with a clot in the early postoperative follow-up. Observations: A 66 year-old woman with primary open angle glaucoma and cataract received combined cataract surgery plus CyPass in the right eye. Surgery was uneventful, however, there was a small amount of hyphema related to bleeding around the site of Cypass insertion. Intraocular pressure (IOP) was between 6 and 7 mmHg in the first week on no glaucoma medications...
June 2018: American Journal of Ophthalmology Case Reports
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