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q switched laser

Mingqi Fan, Tao Li, Guiqiu Li, Houyi Ma, Shengzhi Zhao, Kejian Yang, Christian Kränkel
The saturable absorption properties of few-layer graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>) nanosheets near 3 μm were investigated. A stable Q-switched Er:Lu<sub>2</sub>O<sub>3</sub> laser at 2.84 μm was realized by using a home-made g-C<sub>3</sub>N<sub>4</sub> saturable absorber (SA), generating a pulse duration of 351 ns and an average output power of 1.09 W at a repetition rate of 99 kHz, corresponding to a pulse energy of 11...
January 15, 2017: Optics Letters
Qiyao Liu, Bin Zhang, Sisheng Qi, Yaocheng Li, Xuliang Fan, Yongguang Zhao, Wei Zhou, Deyuan Shen
Using a home-made black phosphorus plate (BPP) as handedness controller and Q-switch modulator synchronously, a ~1.6 µm pulsed vortex laser with well-determined handedness is demonstrated in this letter. Stable vortex pulses of LG<sub>0, + 1</sub>, LG<sub>0,-1</sub>, LG<sub>0, + 2</sub> and LG<sub>0,-2</sub> modes were respectively achieved from compact resonant cavities in this experiment. Such pulsed vortex laser should have promising applications in various fields based on its simple structure, controllable handedness, and carried orbital angular momentum...
December 26, 2016: Optics Express
H Cheng, W Lin, T Qiao, S Xu, Z Yang
With increasing demand on a laser source in the gigahertz pulse repetition rate regime, clarification on the mechanism of instability in high repetition rate fiber lasers - a promising alternative to solid state lasers - is of great importance and can potentially offer guideline for continuous wave (CW) mode locking. Here we present a theoretical approach together with relevant experimental corroboration to analyze the instabilities. By means of appropriate approximations, regimes from Q-switched mode locking, CW mode locking and pulsation are theoretically identified...
December 26, 2016: Optics Express
E Petronijevic, C Sibilia
Electromagnetically induced transparency (EIT) is a pump-induced narrowband transparency window within an absorption line of the probe beam spectrum in an atomic system. In this paper we propose a way to bring together the all-dielectric metamaterials to have EIT-like effects and to optically tune the response by hybridizing them with a layer of a phase change material. We propose a design of the metamaterial based on Si nanoresonators that can support an EIT-like resonant response. On the top of the resonators we consider a thin layer of a chalcogenide phase change material, which we will use to tune the optical response...
December 26, 2016: Optics Express
Jingjing Liu, Jie Liu, Zhinan Guo, Han Zhang, Weiwei Ma, Jingya Wang, Liangbi Su
An efficient Er:SrF<sub>2</sub> crystal, lightly Er-doped to a concentration of 4at.%, was successfully grown by the traditional Bridgman method and displayed excellent spectral properties. A diode-end-pumped passively Q-switched dual-wavelength laser, operating at 2.79 μm wavelength, was demonstrated with this crystal by using black phosphorus as the saturable absorber (BP-SA). In the compact passively Q-switched Er:SrF<sub>2</sub> laser, the maximum average output power of 180 mW was achieved at an absorbed pump power of 2...
December 26, 2016: Optics Express
Spela Stunf Pukl, Brigita Drnovšek-Olup
PURPOSE: To evaluate the efficacy of selective laser trabeculoplasty (SLT) to lower intraocular pressure (IOP) in patients with primary open-angle glaucoma (POAG), normal tension glaucoma (NTG) or ocular hypertension (OHT), when performed with laser pulse duration of 1 ns compared with standard 3-5 ns. METHODS: Bilateral SLT with a 532 nm Q-switched neodymium-doped yttrium aluminium garnet laser was conducted in 30 patients (60 eyes) with POAG (n = 5), NTG (n = 2) or OHT (n = 23)...
December 31, 2016: International Ophthalmology
Sargis Hakobyan, Valentin J Wittwer, Kore Hasse, Christian Kränkel, Thomas Südmeyer, Thomas Calmano
In this Letter, we present high-power continuous wave (CW) and Q-switched femtosecond laser-written Yb:YAG channel waveguide lasers. In Q-switched operation, obtained by a semiconductor saturable absorber mirror (SESAM), as well as in CW operation, the laser generates average output powers of more than 5.6 W and reaches slope efficiencies above 74%. The Q-switched laser operated at a maximum repetition rate of 5.4 MHz with a minimum pulse duration of 11 ns, and with a maximum pulse energy of 1 μJ. This laser has almost an order of magnitude higher average output power than previously reported Q-switched channel waveguide lasers...
October 15, 2016: Optics Letters
Jingjing Liu, Xiuwei Fan, Jie Liu, Weiwei Ma, Jingya Wang, Liangbi Su
A diode-end-pumped self-Q-switched mid-infrared laser was demonstrated with Er<sup>3+</sup>, Pr<sup>3+</sup> co-doped CaF<sub>2</sub> crystal for, to the best of our knowledge, the first time. Maximum average output power of 262 mW was achieved and the corresponding slope efficiency was 14.9%. Stable self-Q-switched laser pulses as short as 718 ns were obtained with a repetition rate of 52.63 kHz at the center wavelength of 2803.7 nm. This highly compact nanosecond laser using a 3 at...
October 15, 2016: Optics Letters
Sang Ju Lee, Joon Seok, Kui Young Park, Seong Jun Seo
No abstract text is available yet for this article.
December 19, 2016: Dermatologic Surgery: Official Publication for American Society for Dermatologic Surgery [et Al.]
Inbok Lee, Aoqi Zhang, Changgil Lee, Seunghee Park
This paper proposes a non-contact nondestructive evaluation (NDE) technique that uses laser-induced ultrasonic waves to visualize corrosion damage in aluminum alloy plate structures. The non-contact, pulsed-laser ultrasonic measurement system generates ultrasonic waves using a galvanometer-based Q-switched Nd:YAG laser and measures the ultrasonic waves using a piezoelectric (PZT) sensor. During scanning, a wavefield can be acquired by changing the excitation location of the laser point and measuring waves using the PZT sensor...
December 16, 2016: Sensors
Jyotsana Singh, Rohit Kumar, Shikha Awasthi, Vinti Singh, A K Rai
Laser-induced breakdown spectroscopy (LIBS) was investigated to estimate the viability as a simple and rapid method for analysis of nutrient elements in seed kernels of cucurbits. LIBS spectra were recorded in the range of 200-975nm by using Q-switched Nd:YAG laser at 532nm (4ns, 10Hz) attached to echelle spectrometer with intensified charged coupled device (ICCD). The spectral analysis revealed the presence of several elements like C, O, N, Mg, Ca, Na and K in seeds. The quantification of elements (Mg, Ca, Na and K) through LIBS was done using calibration curve method in which all calibration curve shows good linearity (r>0...
April 15, 2017: Food Chemistry
Oma Agbai, Iltefat Hamzavi, Jared Jagdeo
Importance: Lasers are gaining interest as a treatment option for postinflammatory hyperpigmentation (PIH) but can pose a clinical dilemma given the risk for laser-induced or exacerbated PIH. Objective: To assess the clinical evidence for the use of lasers in the treatment of PIH. Evidence Review: A systematic review was performed by searching PubMed databases from January 1, 1990, through May 31, 2016. Included studies involved laser treatment for PIH with the degree of pigmentation as a measure of outcome...
December 14, 2016: JAMA Dermatology
Hongyu Luo, Jianfneg Li, Jitao Xie, Bo Zhai, Chen Wei, Yong Liu
We reported a high average power and energy microsecond pulse erbium-doped fluoride fiber MOPA system centered at 2786.8 nm. The master oscillator was a passively Q-switched erbium-doped fluoride fiber laser based on SESAM in a linear cavity. Then a one-stage erbium-doped fluoride fiber amplifier was used to boost its average output power to 4.2 W and pulse energy to 58.87 μJ. The pulse duration and repetition rate were 2.29 µs and 71.73 kHz, respectively. To the best of our knowledge, the achieved average output power and pulse energy are the recorded levels for the passively Q-switched fiber lasers at 3 μm wavelength region...
December 12, 2016: Optics Express
Lihe Zheng, Arvydas Kausas, Takunori Taira
Intense pulse pumped microlaser is proposed for high peak power and low timing jitter at high repetition rate. It is based on Intense and Fast Pulse Pump (IFPP) technique, in which fast pulse pumps up the upper-level population and then dumps it rapidly by Q-switching. That could come close to complete pumping efficiency to reduce thermal problems and contribute to suppress the timing jitter of passively Q-switched laser. In this work, linearly polarized 1064 nm beam from [100]-cut YAG/Nd3+:YAG and [110]-cut Cr4+:YAG passively Q-switched microlaser is directly guided into nonlinear crystals to obtain 532 nm and 266 nm output...
December 12, 2016: Optics Express
Ryohei Morimoto, Taichi Goto, John Pritchard, Hiroyuki Takagi, Yuichi Nakamura, Pang Boey Lim, Hironaga Uchida, Mani Mina, Takunori Taira, Mitsuteru Inoue
A 10-mm cavity length magnetooptically Q-switched Nd:GdVO4 laser was demonstrated using a single-crystalline ferrimagnetic rare-earth iron garnet film. To design the Q-switching system, the magnetic, optical, and magnetooptical properties of the garnet film were measured. The diode pumped solid-state laser cavity was constructed using a 190-μm-thick garnet film with 58% transmittance. The garnet film had maze-shaped magnetic domains, and the domain walls disappeared when a field of over 200 Oe was applied...
December 8, 2016: Scientific Reports
Janet Y Li, Elizabeth Rc Geddes, Deanne M Robinson, Paul M Friedman
Melasma is a pigmentary disorder of unclear etiology with numerous treatment options and high recurrence rates. Laser and light therapies may be utilized cautiously as second- or third-line options for recalcitrant melasma, but low-energy settings are preferred due to the risk of postinflammatory hyperpigmentation and melasma stimulation. Commonly used lasers include the low-fluence 1064-nm Q-switched neodymium-doped yttrium aluminum garnet laser, nonablative fractionated lasers, and intense pulsed light. Strict sun protection, concomitant use of bleaching agents, and maintenance treatments are necessary...
December 2016: Seminars in Cutaneous Medicine and Surgery
Hee Won Jang, Seung Hyun Chun, Hae Chul Park, Hwa Jung Ryu, Il-Hwan Kim
BACKGROUND: Recently dual-pulsed low-fluence 1,064 nm Q-switched Nd:YAG (QSNY) laser has been developed for reducing complication during melasma treatment. OBJECTIVE: Comparison of the efficacy and safety between dual-pulsed mode and single-pulsed mode for the treatment of melasma. MATERIALS AND METHODS: In preclinical study, adult zebrafish were irradiated with dual-pulsed and single-pulsed mode. Changes of melanophore and cell death were assessed...
December 2, 2016: Journal of Cosmetic and Laser Therapy: Official Publication of the European Society for Laser Dermatology
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
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