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q switched laser

Naoki Morimoto, Natsuko Kakudo, Ayako Kako, Keiko Nishimura, Toshihito Mitsui, Ryohei Miyake, Atsuyuki Kuro, Masakatsu Hihara, Kenji Kusumoto
In Japan, the JACE(®) cultured epidermal autograft (CEA) was approved and covered by public healthcare insurance for use in the treatment of giant congenital melanocytic nevus (GCMN) in 2016. We herein report the results of the application of JACE(®) after curettage and Q-switched ruby laser therapy. The current patient was the first patient with GCMN to be treated with JACE(®) since its approval. A 3-month-old girl had a hairy GCMN of 9.5 cm in diameter from her cheek to her temple on the left side of her face...
November 17, 2017: Journal of Artificial Organs: the Official Journal of the Japanese Society for Artificial Organs
Yi-Ran Wang, Peng Lee, Bai-Tao Zhang, Yuan-Hua Sang, Jing-Liang He, Hong Liu, Chao-Kuei Lee
Saturable absorbers (SAs) have interesting applications for the realization of pulsed lasers in various wavelengths of fiber and solid-state lasers. Topological insulators (TIs) have been recently discovered to feature saturable absorption due to their unique band structure. In this study, high-purity layers of Bi2Te3 thin film SA have been successfully prepared using the spin coating-coreduction approach (SCCA). Compared with the typical method of preparing SAs, the SCCA can be used to prepare topological insulator saturable absorbers (TISAs) with high optical quality, large area consistency, and controllable thickness, which is critical for pulsed lasers...
November 16, 2017: Nanoscale
Sahar Ghannam, Fatemah K Al Otabi, Konstantin Frank, Sebastian Cotofana
<p>OBJECTIVE: Post-inflammatory hyperpigmentation results in aesthetically unpleasant discoloration of the skin in the affected area. The efficacy of low-fluence Q-switched 1064-nm Nd:YAG laser has so far not been evaluated for the treatment of the axilla. This observational study was designed to evaluate whether the application of the laser treatment can satisfactorily reduce axillary hyperpigmentation. MATERIAL AND METHODS: 17 females (mean age, 34.27 ± 9.24; range, 19-48) were treated in a single center between 2014 and 2016 for post-inflammatory hyperpigmentation of the axillary area...
November 1, 2017: Journal of Drugs in Dermatology: JDD
Maxim Demesh, Daniel-Timo Marzahl, Anatol Yasukevich, Viktor Kisel, Günter Huber, Nikolay Kuleshov, Christian Kränkel
We report on a 2ω-OPSL-pumped passively Q-switched Pr(3+):LiYF4 laser operating at the wavelengths of 523, 607, and 640 nm. For this, we utilized a Co(2+)-doped MgAl2O4 (MALO) crystal as a saturable absorber in the visible range for the first time, to the best of our knowledge. In the green spectral region, the pulse duration was 210 ns with a pulse energy of 3.6 μJ and a repetition rate of 125 kHz. The minimum pulse duration of 87 ns at the highest pulse energy of 8.6 μJ was obtained at a repetition rate of 110 kHz at 607 nm...
November 15, 2017: Optics Letters
Ryohei Morimoto, Taichi Goto, Takunori Taira, John Pritchard, Mani Mina, Hiroyuki Takagi, Yuichi Nakamura, Pang Boey Lim, Hironaga Uchida, Mitsuteru Inoue
Diode-pumped solid-state micro lasers are compact (centimetre-scale), highly stable, and efficient. Previously, we reported Q-switched lasers incorporating rare-earth substituted iron garnet (RIG) film. Here, the first demonstration of the magnetooptical (MO) Q-switch in an Nd:YAG laser cavity is performed. We fabricate a quasi-continuous-wave (QCW) diode-pumped Nd:YAG laser cavity, which is shortened to 10 mm in length and which contains an RIG film and a pair of small coils. This cavity yields a 1,064.58-nm-wavelength pulse with 25-ns duration and 1...
November 13, 2017: Scientific Reports
Daniel A Belkin, Hana Jeon, Elliot Weiss, Jeremy A Brauer, Roy G Geronemus
OBJECTIVE: Nevus of Ota represents congenital dermal melanocytosis in a trigeminal distribution, most commonly occurring in Asian individuals and other individuals with skin of color. Evidence suggests early treatment is beneficial. Multiple reports have shown efficacy and safety of Q-switched laser treatment in adults. There is little data on children and in non-Asian skin types. This series was done to demonstrate safe and effective use of Q-switched laser therapy in children of multiple skin types...
November 13, 2017: Lasers in Surgery and Medicine
André L Moura, Pablo I R Pincheira, Albert S Reyna, Ernesto P Raposo, Anderson S L Gomes, Cid B de Araújo
We demonstrate the replica symmetry breaking (RSB) phenomenon in the spontaneous mode-locking regime of a multimode Q-switched Nd:YAG laser. The underlying mechanism is quite distinct from that of the RSB recently observed in random lasers. Here, there is no random medium and the phase is not glassy with incoherently oscillating modes as in random lasers. Instead, in each pulse a specific subset of longitudinal modes are activated in a nondeterministic way, whose coherent oscillation dominates and frustrates the others...
October 20, 2017: Physical Review Letters
Wentao Wu, Xudong Li, Renpeng Yan, Yiping Zhou, Yufei Ma, Rongwei Fan, Zhiwei Dong, Deying Chen
We demonstrated a cavity-dumped burst-mode 1.06 μm side-pumped Nd:YAG laser and its dual-stage dual-pass amplified laser performance. The cavity dumping process has been theoretically studied and the output performance has been experimentally investigated. At the pumping duration of 2 ms and pumping frequency of 10 Hz, burst energy, peak power and pulse width of the amplified laser reached 1.89 J, 2.87 MW and 3.1 ± 0.3 ns, respectively, at the Q-switch repetition rate of 100 kHz. The maximum energy extraction efficiency reaches to 30%...
October 30, 2017: Optics Express
C A M Eggen, J E Lommerts, E J van Zuuren, J Limpens, S G M A Pasmans, A Wolkerstorfer
Recent studies on congenital melanocytic nevi (CMN) indicate a lower risk for melanoma than assumed for many years. As a result, the treatment paradigm in CMN shifted from complete removal to cosmetically acceptable, less invasive treatment options such as laser treatment. Our objective was to systematically review the efficacy and safety of laser therapy for CMN. We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL) and PubMed. We rated the quality of evidence with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach...
October 27, 2017: British Journal of Dermatology
Jinde Yin, Hao Chen, Wei Lu, Mengli Liu, Irene Ling Li, Min Zhang, Wenfei Zhang, Jinzhang Wang, Zihan Xu, Peiguang Yan, Wen-Jun Liu, Shuang Chen Ruan
Transition metal dichalcogenides (TMDs) have been successfully used as broadband optical modulator materials for pulsed fiber laser systems. However, the nonlinear optical absorptions of exfoliated TMDs are strongly limited by their nanoflakes morphology with uncontrollable lateral size and thickness. In this work, we provide an effective method to fully explore the nonlinear optical properties of MoSe2. Large-area and high quality lattice MoSe2 grown by chemical vapor deposition method was adopted as an optical modulator for the first time...
October 23, 2017: Nanotechnology
Fatma Saleh, Noha H Moftah, Eman Abdel-Azim, Marwa G Gharieb
BACKGROUNDS: Treatment of mixed melasma remains challenging. Promising results have been achieved with low-fluence 1064-nm Q-switched Nd-YAG laser; however, multiple sessions are necessary with occurrence of complications especially in dark skin types. So, combination methods may be recommended. AIMS: To compare efficacy of Q-switched Nd-YAG laser alone or with modified Jessner's peel in mixed melasma in dark skin. PATIENTS/METHODS: Nineteen patients with mixed melasma received 6 sessions of laser on left side of face and alternating laser and modified Jessner on right side...
October 22, 2017: Journal of Cosmetic Dermatology
Ke-Xun Huang, Bao-Le Lu, Diao Li, Xin-Yuan Qi, Hao-Wei Chen, Na Wang, Zeng-Run Wen, Jin-Tao Bai
We demonstrate a passively Q-switched ytterbium-doped fiber laser based on black phosphorus (BP) flakes covered microfiber. The BP saturable absorber is fabricated by sandwiching a microfiber between two pieces of polydimethylsiloxane supported BP flakes film, which is prepared by the mechanical exfoliation method. In this case the BP flakes can be well protected from the action of air and moisture. By incorporating BP flakes covered microfiber into a ytterbium-doped ring fiber laser, stable and reliable Q-switched operation at 1064 nm can be realized via interaction between few-layers BP flakes and the evanescent field of the laser...
August 10, 2017: Applied Optics
Wen-Song Li, Quan Ma, Jia-Ji Wu, Hui-Ying Xu, Zhi-Ping Cai
We report the experimental investigation of visible passively Q-switched Pr(3+)-doped all-fiber lasers with tungsten disulfide (WS2) saturable absorber, where red-light short-pulse generations from different output mirror transmissions are systemically characterized. The proposed simple and compact all-fiber linear cavity was constructed by a fiber-pigtail-based blue laser-diode pump, a Pr(3+)-doped fluorozirconate glass active fiber, and the fiber end-facet mirrors. Integrating a free-standing layered WS2 film into the laser cavity initiated the Q-switching operation...
September 20, 2017: Applied Optics
Monir Morshed, Haroldo T Hattori, Ahasanul Haque, Benjamin C Olbricht
Magnesium diboride (MgB2) is a well-known superconductor at temperatures below 39 K. At higher temperatures, it behaves as a lossy material. In this paper, we examine the performance of MgB2 nano-particles as saturable absorber in a ytterbium-doped fiber ring laser at room temperature: we show that the nano-particles can produce pulses between 200 and 1700 ns. The dynamics of the saturable absorber are both examined as a stand-alone saturable absorber and in combination with an acousto-optic modulator. We believe, to the best of our knowledge, that this is the first time that MgB2 is used as a saturable absorber in a Q-switched laser...
September 20, 2017: Applied Optics
Wenqi Zhang, Yijie Shen, Yuan Meng, Mali Gong
An 888 nm pumped quasi-single-crystal-fiber (quasi-SCF) acousto-optic Q-switched Nd:YVO4 laser is experimentally demonstrated for the first time, where two closely jointed crystals with different side surface styles serve as a long thin medium to improve the pump absorption and alleviate thermal load. In continuous-wave operation, the highest output power can reach 38.7 W with corresponding optical-optical efficiency of 0.492. In Q-switched operation, the optical-optical efficiency increases from 0.347 to 0...
September 20, 2017: Applied Optics
Hanjun Luo, Zhengbiao Ouyang, Qiang Liu, Zhenli Lu, Bin Li
There exists a performance limitation in a pulsed Geiger-mode avalanche photodiode laser ranging system because of the echo intensity random fluctuation caused by turbulence effects. To suppress the influence of turbulence effects, we present a cumulative pulse detection technique with the ability to achieve improved cumulative probabilities and range accuracy. Based on the modulated Poisson model, the cumulative probabilities, range accuracy, and their influencing factors are investigated for a cumulative Q-switched laser pulse train...
October 10, 2017: Applied Optics
Mingyin Yao, Gangfu Rao, Lin Huang, Muhua Liu, Hui Yang, Jinyin Chen, Tianbing Chen
Laser-induced breakdown spectroscopy (LIBS) as a rapid and green method was used to detect heavy metals Cr and Pb in pork contaminated in the lab. The laser-induced plasma was generated by a Q-switched Nd:YAG laser, and the LIBS signal was collected by a spectrometer with a charge-coupled device detector. The traditional calibration curves (CC) and multivariate partial least squares (PLS) algorithm were applied and compared to validate the accuracy in predicting the content of heavy metals in samples. The results demonstrated that the correlation coefficient of CC is poor by the classical univariate calibration method, so the univariate calibration analysis cannot effectively serve the quantitative purpose in analyzing heavy metals' residue in pork with a complex matrix...
October 10, 2017: Applied Optics
Zhongwei Xu, Xing Luo, Luyun Yang, Jinggang Peng, Haiqing Li, Jinyan Li
We report on a passively Q-switched Yb-doped all-fiber (YDF) ring laser based on stimulated Brillouin scattering (SBS) feedback in a 20-m single-mode fiber (SMF). The Q-switched pulses are generated from the Stokes pulses of SBS and amplified in the YDF. The 10-ns self-Q-switched pulses with ∼1  kW maximum peak power are obtained. The repetition frequency of the pulse train is tuned from 4 to 12.6 kHz by changing the pump power in the experiment. A bandpass filter inserted in the laser cavity was used to suppress the time jitter of the Q-switched pulses...
June 10, 2017: Applied Optics
Konstantin Gorbachenya, Viktor Kisel, Anatoly Yasukevich, Pavel Loiko, Xavier Mateos, Viktor Maltsev, Nikolai Leonyuk, Magdalena Aguiló, Francesc Díaz, Uwe Griebner, Valentin Petrov, Nikolai Kuleshov
A single-layer graphene saturable absorber is employed for passive Q-switching of an Er, Yb:GdAl3(BO3)4 (Er,Yb:GdAB) compact laser, representing the first Er-doped oxoborate laser Q-switched by graphene. This laser is based on a c-cut 1.8 at. % Er(3+), 15 at. % Yb(3+):GdAB crystal diode-pumped at 0.976 μm. It generates a maximum average output power of 360 mW at 1.55 μm with a slope efficiency of 23% (with respect to the incident power). Stable ∼1  μJ/130  ns pulses are achieved at a repetition rate of 400 kHz...
June 1, 2017: Applied Optics
Sarah Kadhim Mohsin Al-Hayali, Dunya Zeki Mohammed, Wurood Abdulkhaleq Khaleel, Abdul Hadi Al-Janabi
We report on aluminum oxide nanoparticles (Al2O3 NPs) as a saturable absorber (SA) for passively Q-switched erbium-doped fiber laser (EDFL) operating at a wavelength of 1560.6 nm within the C-band region. A thin film of Al2O3-SA was prepared using polyvinyl alcohol (PVA) as a host polymer. Very stable pulses with a 57.8 KHz repetition rate and 5.6 μs pulse width at a threshold pump power of 158 mW were obtained. A 2.8 μs pulse width, 81 kHz pulse repetition rate, with maximum pulse energy of 56.7 nJ at a diode pump power of 330 mW were recorded...
June 1, 2017: Applied Optics
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