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q switched laser

Mohammed Ashraf, Touka Banaee, Fabiana Q Silva, Rishi P Singh
BACKGROUND AND OBJECTIVE: Anti-vascular endothelial growth factor (VEGF) therapy is the treatment of choice for cases with neovascular age-related macular degeneration (AMD). Switching to an alternate anti-VEGF has been suggested as a possible option for resistant cases. The purpose of this review is to evaluate whether the timing of switching affects treatment outcomes. PATIENTS AND METHODS: A review of published literature was performed looking at all studies where patients with refractory neovascular AMD were switched to an alternative anti-VEGF...
March 1, 2018: Ophthalmic Surgery, Lasers & Imaging Retina
Can Cihan, Abdullah Muti, Isinsu Baylam, Askin Kocabas, Umit Demirbas, Alphan Sennaroglu
We report, to the best of our knowledge, the shortest femtosecond pulses generated from a Kerr-lens mode-locked (KLM) Alexandrite laser operating near 750 nm. The Alexandrite gain medium was pumped with a continuous-wave (cw), 532 nm laser, and the performance of both the short and extended resonators was investigated. The use of an extended cavity eliminated the multi-wavelength spectral instabilities observed during the cw operation of the short cavity. Furthermore, since the repetition rate of the Alexandrite laser was reduced from 107 to 5...
March 15, 2018: Optics Letters
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
Junli Wang, Lei Chen, Chenxi Dou, Haiting Yan, Lingjie Meng, Zhiyi Wei
In this work, we fabricate the Mo<sub>0.5</sub>W<sub>0.5</sub>S<sub>2</sub> by microwave-assisted solvothermal method, and report the Q-switched Yb-doped fiber lasers using Mo<sub>0.5</sub>W<sub>0.5</sub>S<sub>2</sub> nanosheets polymer film and tapered fiber as the saturable absorbers (SAs). The modulation depth and saturable intensity of the film SA are 5...
March 12, 2018: Nanotechnology
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
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
Punyaphat Sirithanabadeekul, Rattima Srieakpanit
INTRODUCTION: Post-inflammatory hyperpigmentation (PIH) after solar lentigo removal using a Q-switched (QS) 532-nm Nd:YAG laser is a cause for concern. This study aimed to evaluate the efficacy and safety of intradermal injections of tranexamic acid (TA) at reducing the risk of PIH after QS 532-nm Nd:YAG laser treatment of solar lentigines. METHODS: Twenty-five patients with 50 solar lentigines on forearms underwent QS 532-nm Nd:YAG laser treatment. Then, TA (50 mg/mL) was injected randomly into one lesion and 0...
March 5, 2018: Journal of Cosmetic and Laser Therapy: Official Publication of the European Society for Laser Dermatology
Wensong Li, Jiaji Wu, Xiaofeng Guan, Zhiyong Zhou, Huiying Xu, Zhengqian Luo, Zhiping Cai
In this work, efficient visible Ho3+ -doped fluorozirconate glass (Ho:ZBLAN) all-fiber lasers operating in continuous-wave (CW) and Q-switching regimes are experimentally demonstrated. The combination of a direct blue pump, a highly-doped Ho:ZBLAN fiber and the fiber end-facet mirrors contributes to a simple all-fiber configuration. A tunable laser emission in the green spectral range of 543-550 nm is achieved with >150 mW output power and a tunable deep-red laser around 754-758 nm is also obtained with about 16 mW output power...
March 2, 2018: Nanoscale
Adone Baroni
Xanthelasma palpebrarum is the most common type of xanthoma affecting the eyelids. It is characterized by asymptomatic soft yellowish macules, papules, or plaques over the upper and lower eyelids. Many treatments are available for management of xanthelasma palpebrarum, the most commonly used include surgical excision, ablative CO2 or erbium lasers, nonablative Q-switched Nd:YAG laser, trichloroacetic acid peeling, and radiofrequency ablation. This study aims to evaluate the effectiveness of RF ablation in the treatment of xanthelasma palpebrarum, with D...
March 1, 2018: Journal of Cosmetic Dermatology
Vijay Zawar, Aarti Sarda, Abhishek De
No abstract text is available yet for this article.
October 2017: Journal of Cutaneous and Aesthetic Surgery
Wenchao Duan, Hongkun Nie, Xiaoli Sun, Baitao Zhang, Guanbai He, Qi Yang, Haibing Xia, Ruihua Wang, Jie Zhan, Jingliang He
High-quality gold (Au) nanospheres (Au-NPs) with a diameter of 52 nm were prepared by the seeded growth method. The mid-infrared (MIR) nonlinear saturable absorption properties were measured by a balanced twin-detector measurement technique. With the as-prepared Au-NPs saturable absorber (SA), an efficient passively Q-switched laser was realized at 2.95 μm for the first time, to the best of our knowledge. Under an absorbed pump power of 4.0 W, a maximum output power of 268 mW was obtained with the shortest pulse width of 734 ns and repetition rate of 91 kHz, corresponding to the pulse energy up to 2...
March 1, 2018: Optics Letters
Brian Cole, Lew Goldberg, Stephen Chinn, Leonard A Pomeranz, Kevin T Zawilski, Peter G Schunemann, John McCarthy
We describe a compact and efficient mid-infrared (mid-IR) source based on zinc germanium phosphide (ZGP) and cadmium silicon phosphide (CSP) optical parametric oscillators (OPOs), operating in near degenerate condition, directly pumped by a 1.94 μm thulium (Tm)-doped yttrium-aluminum-perovskite (YAP) laser. The Tm:YAP laser is passively Q-switched by a chromium-doped zinc sulfide saturable absorber, and is operated to 4 W average power with a peak power of 29 kW. The laser emission was used to pump CSP and ZGP doubly resonant linear OPO cavities, generating a maximum 3...
March 1, 2018: Optics Letters
Krista Bohnert, Andrew Dorizas, Neil Sadick
Treating photoaging with laser technologies has increased in popularity due to their efficacy, minimal downtime, and side effects. New Q-Switched (QS) Nd:YAG lasers' frequency doubled with 532 nm wavelength can both target epidermal chromophores as well as stimulate collagen production. The objective of this study was to compare single-pulsed 1064-nm Nd:YAG with dual-pulsed 532-nm/1064-nm QS laser for reducing solar lentigines. Ten subjects with solar lentigines were enrolled in this prospective, randomized, double-blind, split-face study...
February 26, 2018: Journal of Cosmetic and Laser Therapy: Official Publication of the European Society for Laser Dermatology
Esrom Kifle, Xavier Mateos, Pavel Loiko, Sun Yung Choi, Ji Eun Bae, Fabian Rotermund, Magdalena Aguiló, Francesc Díaz, Uwe Griebner, Valentin Petrov
A Tm3+ monoclinic double tungstate planar waveguide laser is passively Q-switched (PQS) by a saturable absorber (SA) based on single-walled carbon nanotubes (SWCNTs) randomly oriented in a polymer film. The laser is based on a 18 µm-thick 5 at.% Tm:KY1 -x-yGdxLuy(WO4 )2 active layer grown on an undoped (010)-oriented KY(WO4 )2 substrate by liquid phase epitaxy with determined propagation losses 0.7 ± 0.2 dB/cm. The PQS laser generated a maximum average output power of 45.6 mW at 1.8354 µm with a slope efficiency of 22...
February 19, 2018: Optics Express
Mengixa Wang, Fang Zhang, Zhengping Wang, Zhixin Wu, Xinguang Xu
Based on the saturable absorption feature of a two-dimensional (2D) nano-material, antimonene, the passively Q-switched operation for solid-state laser was realized for the first time. For the 946 and 1064 nm laser emissions of the Nd:YAG crystal, the Q-switched pulse widths were 209 and 129 ns, and the peak powers were 1.48, 1.77 W, respectively. For the 1342 nm laser emission of the Nd:YVO4 crystal, the Q-switched pulse width was 48 ns, giving a peak power of 28.17 W. Our research shows that antimonene can be used as a stable, broadband optical modulating device for a solid-state laser, which will be particularly effective for long wavelength operation...
February 19, 2018: Optics Express
Sourav Das Chowdhury, Atasi Pal, Sayan Chatterjee, Ranjan Sen, Mrinmay Pal
In this paper, we propose an all-normal-dispersion ytterbium-fiber laser with a novel ring cavity architecture having two nonlinear amplifying loop mirrors (NALM) as saturable absorbers, capable of delivering distinctly different pulses with adjustable features. By optimizing the loop lengths of the individual NALMs, the cavity can be operated to deliver Q-switched mode-locked (Q-ML) pulse bunches with adjustable repetition rates, mode-locked pulses in dissipative soliton resonance (DSR) regime or noise-like pulse (NLP) regime with tunable pulse width...
February 10, 2018: Applied Optics
Manuel Messner, Arne Heinrich, Karl Unterrainer
This work presents a novel diode side-pumping scheme for Er:YLF with a characteristic laser emission at 2.81 μm. Average output powers greater than 10 W and corresponding pulse energies exceeding 100 mJ with a high slope efficiency of 18.7% are achieved. The Er:YLF laser efficiently operates at room-temperature cooling water and maintains a good beam quality of M2 <12 in the major axis and M2 <6 in the minor axis of the beam profile. The laser cavity is studied by means of Findlay-Clay analysis, and the operation at characteristic pump parameters is investigated...
February 20, 2018: Applied Optics
Sicong Liu, Yani Zhang, Lu Li, Yonggang Wang, Ruidong Lv, Xi Wang, Zhendong Chen, Lianglei Wei
A stable Q-switched Er-doped fiber (EDF) laser is successfully obtained by using a black phosphorus (BP)/polymethyl methacrylate (PMMA) film as the saturable absorber (SA). To avoid the oxidization of nanomaterials, the BP nanoparticles are fabricated via a liquid-phase exfoliation method and then embedded into a PMMA film that possesses excellent optical transparency in the selected spectrum range. The modulation depth (MD) of the BP/PMMA film SA is 14.3% and the saturable intensity (Isat ) is 6.9  MW/cm2 ...
February 20, 2018: Applied Optics
Variya Laothaworn, Premjit Juntongjin
BACKGROUND: A QS-NdYAG laser (QSNYL) and topical tranexamic acid (TA) have been widely used. However, no study has yet reported the efficacy of using both QSNYL and TA as a combined treatment for melasma. OBJECTIVES: To evaluate the efficacy and adverse effects of topical 3% TA combined with 1064-nm QSNYL as a treatment for melasma. METHODS: A randomized, prospective, split-face, controlled trial was conducted. A 1064-nm QSNYL was performed on the entire face at baseline and 4 weeks later...
February 20, 2018: Journal of Cosmetic and Laser Therapy: Official Publication of the European Society for Laser Dermatology
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