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q switched laser

Yixuan Zhang, Chunqing Gao, Qing Wang, Quanxin Na, Meng Zhang, Qing Ye, Mingwei Gao, Jian Zhang
A 2090 nm injection-seeded Q-switched Ho:YAG ceramic laser pumped by a 1.91 μm fiber-coupled LD is demonstrated in this paper. Single-frequency operation of Q-switched Ho:YAG ceramic laser is achieved by injection seeding technique. The maximum output energy of the single-frequency Q-switched Ho:YAG ceramic laser is 14.76 mJ, with a pulse width of 121.6 ns and a repetition rate of 200 Hz. The half-width of the pulse spectrum measured by heterodyne technique is 3.84 MHz. The fluctuation of the center frequency of the pulsed laser is 1...
November 28, 2016: Optics Express
G M Thomas, A Minassian, X Sheng, M J Damzen
We present the first study of Q-switched Alexandrite lasers under continuous-wave diode-pumping with operation up to 10 kHz repetition rates in TEM<sub>00</sub>, with spatial quality M<sup>2</sup> 1.15. With a pulsed-diode dual-end-pumped design, pulse energy is scaled to a record level of 3 mJ. We also demonstrate, for the first time, cavity-dumped Q-switching of diode-pumped Alexandrite lasers under continuous-wave and pulsed diode-pumping, up to 10 kHz. Pulse energy of 510 μJ is demonstrated with 3 ns pulse duration and 170 kW peak power, in TEM<sub>00</sub> with M<sup>2</sup> < 1...
November 28, 2016: Optics Express
Hwa Jung Ryu, Ji Min Lee, Hee Won Jang, Hae Chul Park, Im Joo Rhyu, Il-Hwan Kim
BACKGROUND: Recently, the pulse-in-pulse mode of intense pulsed light (IPL) has been used increasingly for the treatment of melasma. OBJECTIVE: To observe the morphologic changes in the melanophore in adult zebrafish after irradiation with conventional and pulse-in-pulse IPL and Q-switched Nd:YAG (QSNY) laser. METHODS: Adult zebrafish were irradiated with conventional and pulse-in-pulse mode of IPL. The conditions for conventional IPL were 3 mJ/cm(2), 560 nm filter, and pulse widths of 7, 20, and 35 msec...
December 2016: Annals of Dermatology
K J Ahn, B J Kim, S B Cho
BACKGROUND: Laser therapy is the treatment of choice in tattoo removal. However, the precise mechanisms of laser-tattoo pigment interactions remain to be evaluated. METHODS: We evaluated the geometric patterns of laser-tattoo pigment particle interactions using a tattoo pigment-embedded tissue-mimicking (TM) phantom. RESULTS: A Q-switched (QS) neodymium-doped yttrium aluminum garnet laser was used at settings of 532-, 660-, and 1064-nm wavelengths, single-pulse and quick pulse-to-pulse treatment modes, and spot sizes of 4 and 7 mm...
November 20, 2016: Skin Research and Technology
PikSuan Lau, Noriah Bidin, Shumaila Islam, Wan Norsyuhada Binti Wan Mohd Shukri, Nurlaily Zakaria, Nurfatin Musa, Ganesan Krishnan
BACKGROUND AND OBJECTIVE: The aim of this study is to investigate the effect of gold nanoparticles (AuNPs) in photobiomodulation therapy (PBMT) on wound healing process. MATERIALS AND METHODS: AuNPs are synthesized by Q-switched Nd:YAG laser ablation technique. Cutaneous wound are induced on 45 Sprague Dawley rats on its dorsal part and then randomly divided into three groups. One group serves as non-treatment group (GC) and another two groups are subjected to AuNPs with and without PBMT...
November 12, 2016: Lasers in Surgery and Medicine
Yanmin Duan, Haiyong Zhu, Changwen Xu, Xiukai Ruan, Guihua Cui, Yaoju Zhang, Dingyuan Tang, Dianyuan Fan
We reported a compact self-cascaded KTA-OPO source for 2.6 μm coherent light generation. The OPO is driven in a diode end-pumped and Q-switched Nd:YVO<sub>4</sub> laser cavity. Two OPO processes occurred in the same KTA crystal with non-critical phase matching. At an incident diode pump power of 8.7 W and a pulse repetition frequency of 60 kHz, the OPO can generate a maximum average output power of 445 mW at 2.59 μm. The slope efficiency was about 12.7%, and the power fluctuation was less than 8%...
November 14, 2016: Optics Express
Ming-Hsiung Wu, Yu-Chung Chiu, Tsong-Dong Wang, Gang Zhao, Andrius Zukauskas, Fredrik Laurell, Yen-Chieh Huang
We report superior terahertz parametric generation from potassium titanyl phosphate (KTP) over congruent-grown lithium niobate (CLN) and lithium tantalate (CLT) in terms of parametric gain and laser damage resistance. Under the same pump and crystal configurations, the signal emerged first from KTP, 5% Mg-doped CLN, CLN, and then finally from CLT. The signal growth rate in KTP was comparable to that in 5%-Mg-doped CLN, but the signal power from KTP reached a much higher value after all the other crystals were damaged by the pump laser...
November 14, 2016: Optics Express
Fen Bai, Qingpu Wang, Zhiyong Jiao, Xianfeng Xu, Hui Zhang, Xutang Tao
BaTeMo<sub>2</sub>O<sub>9</sub> (BTM) is employed to achieve efficient stimulated Raman scattering conversion in a diode end-pumped acousto-optically Q-switched Nd:YAG laser. With an incident diode power of 8.6 W, 732 mW of 1179 nm first-Stokes average output power was generated at a pulse repetition rate of 10 kHz, corresponding to a diode-to-Raman conversion efficiency of 8.5%.
November 10, 2016: Applied Optics
Haroldo T Hattori, Abdul Khaleque, Liming Liu, Michael R Greck
Manganese dioxide (MnO<sub>2</sub>) is an abundant material that is widely used in many devices, such as alkaline batteries. At infrared frequencies, MnO<sub>2</sub> is lossy and strongly absorbs light. These characteristics make MnO<sub>2</sub> a potential candidate as a low-cost saturable absorber in Q-switched lasers. In this paper, we examine the performance of MnO<sub>2</sub> as a saturable absorber in an ytterbium-doped Q-switched fiber laser: we show that it can produce pulses with durations ranging from 300 to 1800 ns...
November 10, 2016: Applied Optics
Ali Balevi, Pelin Ustuner, Mustafa Ozdemir
BACKGROUND: Several lasers have been used for the treatment of xanthelasma palpebrarum (XP), such as Q-switched Neodymium:Yttrium Aluminium Garnet (QSNd:YAG), Erbium:Yttrium Aluminium Garnet (Er:YAG) laser. However, there is no comparemental study among these laser options in the treatment of XP. OBJECTIVE: The aim of this study was to compare the clinical efficacy and response rates of QSNd:YAG and Er:YAG in the treatment of XP. METHODS: Sixty patients with a total of 102 XP lesions were randomly and equally divided into two groups...
November 16, 2016: Journal of Cosmetic and Laser Therapy: Official Publication of the European Society for Laser Dermatology
Linan Ma, Yang Tan, Shavkat Akhmadaliev, Shengqiang Zhou, Feng Chen
We demonstrate a tunable hybrid Graphene-Nd:YAG cladding waveguide laser exploiting the electro-optic and the Joule heating effects of Graphene. A cladding Nd:YAG waveguide was fabricated by the ion irradiation. The multi-layer graphene were transferred onto the waveguide surface as the saturable absorber to get the Q-switched pulsed laser oscillation in the waveguide. Composing with appropriate electrodes, graphene based capacitance and heater were formed on the surface of the Nd:YAG waveguide. Through electrical control of graphene, the state of the hybrid waveguide laser was turned on or off...
November 11, 2016: Scientific Reports
Brenda Donelan, Christian Kneis, Giuseppe Scurria, Benoît Cadier, Thierry Robin, Eric Lallier, Arnaud Grisard, Bruno Gérard, Marc Eichhorn, Christelle Kieleck
Optical parametric generation is demonstrated in orientation-patterned gallium arsenide, pumped by a novel single-oscillator simultaneously Q-switched and mode-locked thulium-doped fiber laser, downconverting the pump radiation into the mid-infrared wavelength regime. The maximum output energy reached is greater than 2.0 μJ per pump pulse.
November 1, 2016: Optics Letters
Chenglai Jia, Bhavin J Shastri, Nurmemet Abdukerim, Martin Rochette, Paul R Prucnal, Mohammed Saad, Lawrence R Chen
Dual-band fiber lasers are emerging as a promising technology to penetrate new industrial and medical applications from their dual-band properties, in addition to providing compactness and environmental robustness from the waveguide structure. Here, we demonstrate the use of a common graphene saturable absorber and a single gain medium (Tm(3+):ZBLAN fiber) to implement (1) a dual-band fiber ring laser with synchronized Q-switched pulses at wavelengths of 1480 nm and 1840 nm, and (2) a dual-band fiber linear laser with synchronized mode-locked pulses at wavelengths of 1480 nm and 1845 nm...
November 2, 2016: Scientific Reports
Hyun Ji Kang, Jung Im Na, Jong Hee Lee, Mi Ryung Roh, Joo Yeon Ko, Sung Eun Chang
PURPOSE: To characterize the risk factors of Korean patients for postinflammatory hyperpigmentation (PIH) during treatment of solar lentigines using a Q-switched 532-nm Nd: YAG (QS 532 NY) laser. MATERIALS AND METHODS: The present retrospective multicenter study was conducted at the dermatology clinics of five tertiary hospitals in Korea. Between October 2007 and January 2013, 516 patients were enrolled and reviewed for clinical features and factors associated with PIH...
November 15, 2016: Journal of Dermatological Treatment
Adam B Phillips, Zhaoning Song, Jonathan L DeWitt, Jon M Stone, Patrick W Krantz, John M Royston, Ryan M Zeller, Meghan R Mapes, Paul J Roland, Mark D Dorogi, Syed Zafar, Gary T Faykosh, Randy J Ellingson, Michael J Heben
We have developed a laser beam induced current imaging tool for photovoltaic devices and modules that utilizes diode pumped Q-switched lasers. Power densities on the order of one sun (100 mW/cm(2)) can be produced in a ∼40 μm spot size by operating the lasers at low diode current and high repetition rate. Using galvanostatically controlled mirrors in an overhead configuration and high speed data acquisition, large areas can be scanned in short times. As the beam is rastered, focus is maintained on a flat plane with an electronically controlled lens that is positioned in a coordinated fashion with the movements of the mirrors...
September 2016: Review of Scientific Instruments
Jae-Hui Nam, Young-Jun Choi, Jae Yun Lim, Joon Hong Min, Won-Serk Kim
High-intensity focused ultrasound (HIFU) is regarded as an effective skin-lifting device; however, literature regarding treatment of the aging neck and décolletage with HIFU is scarce. Our study aimed to evaluate the efficacy of combination with HIFU and low-fluence Q-switched Nd:YAG (LQSNY) laser on the aging neck and décolletage. Nineteen women were assessed. HIFU at two visits and LQSNY laser at six visits were used to irradiate the neck and chest. At week 16, improvements were rated using the Dedo classification, Fabi/Bolton Chest Wrinkle Scale (FBCWS), and Global Aesthetic Improvement Scales (GAIS)...
October 20, 2016: Lasers in Medical Science
Erica Roitero, Federico Lasserre, Marc Anglada, Frank Mücklich, Emilio Jiménez-Piqué
OBJECTIVE: The aim of this work is to generate micrometric linear patterns with different topography on dental grade zirconia by means of UV laser interference and to assess the quality of the produced surface, both in term of the geometry produced and of the surface damage induced in the material. METHODS: The third harmonic of a Q-switched Nd:YAG laser (355nm, pulse duration of 10ns and repetition rate of 1Hz) was employed to pattern the surface of 3Y-TZP with micrometric-spaced lines...
October 10, 2016: Dental Materials: Official Publication of the Academy of Dental Materials
Ádám Krolopp, Attila Csákányi, Dóra Haluszka, Dániel Csáti, Lajos Vass, Attila Kolonics, Norbert Wikonkál, Róbert Szipőcs
A novel, Yb-fiber laser based, handheld 2PEF/SHG microscope imaging system is introduced. It is suitable for in vivo imaging of murine skin at an average power level as low as 5 mW at 200 kHz sampling rate. Amplified and compressed laser pulses having a spectral bandwidth of 8 to 12 nm at around 1030 nm excite the biological samples at a ~1.89 MHz repetition rate, which explains how the high quality two-photon excitation fluorescence (2PEF) and second harmonic generation (SHG) images are obtained at the average power level of a laser pointer...
September 1, 2016: Biomedical Optics Express
Yanmin Duan, Haiyong Zhu, Yaoju Zhang, Ge Zhang, Jian Zhang, Dingyuan Tang, A A Kaminskii
An intra-cavity RbTiOPO4 (RTP) cascade Raman laser was demonstrated for efficient multi-order Stokes emission. An acousto-optic Q-switched Nd:YAlO3 laser at 1.08 μm was used as the pump source and a 20-mm-long x-cut RTP crystal was used as the Raman medium to meet the X(Z,Z)X Raman configuration. Multi-order Stokes with multiple Raman shifts (~271, ~559 and ~687 cm(-1)) were achieved in the output. Under an incident pump power of 9.5 W, a total average output power of 580 mW with a pulse repetition frequency of 10 kHz was obtained...
September 26, 2016: Scientific Reports
Jinhwa Gene, Nam Hun Park, Hwanseong Jeong, Sun Young Choi, Fabian Rotermund, Dong-Il Yeom, Byoung Yoon Kim
We demonstrate an optically tunable graphene saturable absorber to manipulate the laser operation in pulsed fiber laser system. Owing to the strongly enhanced evanescent field interaction with monolayer graphene, we could realize an efficient control of modulation depth in the graphene saturable absorber by optical means through cross absorption modulation method. By integrating the tunable graphene saturable absorber into the fiber laser system, we could switch the laser operation from Q-switching through Q-switched mode-locking to continuous wave mode-locking by adjusting only the optical power of the control beam...
September 19, 2016: Optics Express
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