WorldWideScience

Sample records for q-switched waveguide laser

  1. Graphene Q-switched Yb:KYW planar waveguide laser

    NARCIS (Netherlands)

    Kim, Jun Wan; Choi, Sun Young; Aravazhi, S.; Pollnau, Markus; Griebner, Uwe; Petrov, Valentin; Bae, Sukang; Ahn, Kwang Jun; Yeom, Dong-Il; Rotermund, Fabian

    A diode-pumped Yb:KYW planar waveguide laser, single-mode Q-switched by evanescent-field interaction with graphene, is demonstrated for the first time. Few-layer graphene grown by chemical vapor deposition is transferred onto the top of a guiding layer, which initiates stable Q-switched operation in

  2. Q-switched pulse laser generation from double-cladding Nd:YAG ceramics waveguides.

    Science.gov (United States)

    Tan, Yang; Luan, Qingfang; Liu, Fengqin; Chen, Feng; Vázquez de Aldana, Javier Rodríguez

    2013-08-12

    This work reports on the Q-switched pulsed laser generation from double-cladding Nd:YAG ceramic waveguides. Double-cladding waveguides with different combination of diameters were inscribed into a sample of Nd:YAG ceramic. With an additional semiconductor saturable absorber, stable pulsed laser emission at the wavelength of 1064 nm was achieved with pulses of 21 ns temporal duration and ~14 μJ pulse energy at a repetition rate of 3.65 MHz.

  3. Yb:KYW planar waveguide laser Q-switched by evanescent-field interaction with carbon nanotubes

    NARCIS (Netherlands)

    Kim, Jun Wan; Choi, Sun Young; Yeom, Dong-Il; Aravazhi, S.; Pollnau, Markus; Griebner, Uwe; Petrov, Valentin; Rotermund, Fabian

    2013-01-01

    We report Q-switched operation of a planar waveguide laser by evanescent-field interaction with single-walled carbon nanotubes deposited on top of the waveguide. The saturable-absorber-integrated gain medium, which operates based on evanescent-field interaction, enables the realization of a

  4. Bismuth telluride topological insulator nanosheet saturable absorbers for q-switched mode-locked Tm:ZBLAN waveguide lasers

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xiantao; Gross, Simon; Withford, Michael J.; Fuerbach, Alexander [Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) and MQ Photonics Research Centre, Dept. of Physics and Astronomy, Macquarie Univ., NSW (Australia); Zhang, Han; Guo, Zhinan [SZU-NUS Collaborative Innovation Centre for Optoelectronic Science and Technology, Key Lab. of Optoelectronic Devices and Systems of Ministry of Education, College of Optoelectronic Engineering, Shenzhen Univ. (China)

    2016-08-15

    Nanosheets of bismuth telluride (Bi{sub 2}Te{sub 3}), a topological insulator material that exhibits broadband saturable absorption due to its non-trivial Dirac-cone like energy structure, are utilized to generate short pulses from Tm:ZBLAN waveguide lasers. By depositing multiple layers of a carefully prepared Bi{sub 2}Te{sub 3} solution onto a glass substrate, the modulation depth and the saturation intensity of the fabricated devices can be controlled and optimized. This approach enables the realization of saturable absorbers that feature a modulation depth of 13% and a saturation intensity of 997 kW/cm{sup 2}. For the first time to our knowledge, Q-switched mode-locked operation of a linearly polarized mid-IR ZBLAN waveguide chip laser was realized in an extended cavity configuration using the topological insulator Bi{sub 2}Te{sub 3}. The maximum average output power of the laser is 16.3 mW and the Q-switched and mode-locked repetition rates are 44 kHz and 436 MHz, respectively. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Room-temperature subnanosecond waveguide lasers in Nd:YVO4 Q-switched by phase-change VO2: A comparison with 2D materials.

    Science.gov (United States)

    Nie, Weijie; Li, Rang; Cheng, Chen; Chen, Yanxue; Lu, Qingming; Romero, Carolina; Vázquez de Aldana, Javier R; Hao, Xiaotao; Chen, Feng

    2017-04-06

    We report on room-temperature subnanosecond waveguide laser operation at 1064 nm in a Nd:YVO 4 crystal waveguide through Q-switching of phase-change nanomaterial vanadium dioxide (VO 2 ). The unique feature of VO 2 nanomaterial from the insulating to metallic phases offers low-saturation-intensity nonlinear absorptions of light for subnanosecond pulse generation. The low-loss waveguide is fabricated by using the femtosecond laser writing with depressed cladding geometry. Under optical pump at 808 nm, efficient pulsed laser has been achieved in the Nd:YVO 4 waveguide, reaching minimum pulse duration of 690 ps and maximum output average power of 66.7 mW. To compare the Q-switched laser performances by VO 2 saturable absorber with those based on two-dimensional materials, the 1064-nm laser pulses have been realized in the same waveguide platform with either graphene or transition metal dichalcogenide (in this work, WS 2 ) coated mirror. The results on 2D material Q-switched waveguide lasers have shown that the shortest pulses are with 22-ns duration, whilst the maximum output average powers reach ~161.9 mW. This work shows the obvious difference on the lasing properties based on phase-change material and 2D materials, and suggests potential applications of VO 2 as low-cost saturable absorber for subnanosecond laser generation.

  6. Passive Q-switching of femtosecond-laser-written Tm:KLu(WO4)2 waveguide lasers by graphene and MoS2 saturable absorbers

    Science.gov (United States)

    Kifle, Esrom; Mateos, Xavier; Vázquez de Aldana, Javier Rodríguez; Ródenas, Airan; Loiko, Pavel; Zakharov, Viktor; Veniaminov, Andrey; Yu, Haohai; Zhang, Huaijin; Chen, Yanxue; Aguiló, Magdalena; Díaz, Francesc; Griebner, Uwe; Petrov, Valentin

    2018-02-01

    A buried depressed-index channel waveguide with a circular cladding and a core diameter of 40 μm is fabricated in a bulk monoclinic 3 at.% Tm:KLu(WO4)2 crystal by femtosecond direct laser writing. In the continuous-wave regime, the Tm waveguide laser generates 210 mW at 1849.6 nm with a slope efficiency η of 40.8%. Passively Q-switched operation is achieved by inserting transmission-type 2D saturable absorbers (SAs) based on few-layer graphene and MoS2. Using the graphene-SA, a maximum average output power of 25 mW is generated at 1844.8 nm. The pulse characteristics (duration/energy) are 88 ns/18 nJ at a repetition rate of 1.39 MHz.

  7. Q-Switching in a Neodymium Laser

    Science.gov (United States)

    Holgado, Warein; Sola, Inigo J.; Jarque, Enrique Conejero; Jarabo, Sebastian; Roso, Luis

    2012-01-01

    We present a laboratory experiment for advanced undergraduate or graduate laser-related classes to study the performance of a neodymium laser. In the experiment, the student has to build the neodymium laser using an open cavity. After that, the cavity losses are modulated with an optical chopper located inside, so the Q-switching regime is…

  8. Q-switched laser tattoo removal

    Directory of Open Access Journals (Sweden)

    Viljem H. topčič

    2013-10-01

    Full Text Available Background: Decorative tattooing gained popularity in many western countries throughout the 1990s. Some estimates show that approximately 10 % of men in the United States already have tattoos. However, tattoos often become a personal regret. As recent surveys suggest, 17 % of people that have obtained a tattoo and more than 50 % of adults over the age of 40 in the United States of America consider having them removed. The same trend can be observed in our country as well. Laser therapy is the gold standard for tattoo removal. In Slovenia, laser tattoo removal therapy is available and widely accessible. There is a wide range of facilities offering laser tattoo removal, ranging from different private clinics to beauty salons. Different facilities use different lasers, but not all lasers, however, are optimal for successful and complete tattoo removal, as inappropriate use can cause many unwanted side effects.Methods: Eleven (11 patients (2 men and 9 women requesting tattoo removal were treated in our department. When treating our patients, we used Fotona’s QX MAX quality-switched Nd:YAG laser which offers four different wavelengths in a single system; 1064 nm Nd:YAG was used to treat and remove dark pigments, 532 nm KTP for red, tan-colored, purple and orange tattoo inks, 650 nm dye for green tattoo inks and 585 nm dye for sky-blue colored inks.Results: Satisfactory tattoo removal was achieved in all patients treated. Patients were very satisfied with the success and the number of treatments needed for tattoo removal. There were mild unwanted side effects and the pain was moderate. The average number of treatments required for complete tattoo removal was less than 7, ranging from 3 to 21 treatments. Patients’ satisfaction with tattoo removal was estimated at 5.2 (on a scale from 1 to 6.Conclusions: Our study showed that Q-switched lasers successfully remove tattoo ink, however several treatments are required for satisfactory tattoo removal

  9. Numerical modelling of passively Q-switched intracavity Raman lasers

    International Nuclear Information System (INIS)

    Ding Shuanghong; Zhang Xingyu; Wang Qingpu; Zhang Jun; Wang Shumei; Liu Yuru; Zhang Xuehui

    2007-01-01

    Assuming intracavity photon densities to be of Gaussian spatial distributions, the space-dependent rate equations of passively Q-switched intracavity Raman lasers are deduced for the first time for the pumping beams of Gaussian and top-head spatial distributions, respectively. The new rate equations are normalized and solved numerically to investigate the influences of the normalized initial population inversion density, normalized Raman gain coefficient, saturable absorber parameter, beam size ratio of pump to fundamental laser and loss ratio of the first Stokes to fundamental laser on the pulse parameters of the first Stokes. The results of the Gaussian and top-head pumpings show similar trends despite some discrepancies. The new theories and numerical results will help design passively Q-switched intracavity Raman lasers of high performance

  10. Tattoo removal by Q-switched yttrium aluminium garnet laser

    DEFF Research Database (Denmark)

    Hutton Carlsen, K; Esmann, J; Serup, J

    2017-01-01

    BACKGROUND: Tattoo removal by Q-switched yttrium aluminium garnet (YAG) lasers is golden standard; however, clients' satisfaction with treatment is little known. OBJECTIVE: To determine clients' satisfaction with tattoo removal. METHODS: One hundred and fifty-four tattoo removal clients who had...... relative to colour of tattoo on a scale from 0 (no effect) to 10 (complete removal) scored a mean of blue 9.5, black 9.4, yellow 8.9, red 8.8 and green 6.5. Clients were dissatisfied with green pigment remnants, which could mimic bruising. One hundred and twenty-nine clients (84%) experienced moderate...

  11. Removal of Tattoos by Q-Switched Nanosecond Lasers.

    Science.gov (United States)

    Karsai, Syrus

    2017-01-01

    Tattoo removal by Q-switched nanosecond laser devices is generally a safe and effective method, albeit a time-consuming one. Despite the newest developments in laser treatment, it is still not possible to remove every tattoo completely and without complications. Incomplete removal remains one of the most common challenges. As a consequence, particular restraint should be exercised when treating multicoloured tattoos, and patients need to be thoroughly informed about remaining pigment. Other frequent adverse effects include hyper- and hypopigmentation as well as ink darkening; the latter is particularly frequent in permanent make-up. Scarring is also possible, although it is rare when treatment is performed correctly. It is becoming more widespread for laser operators to encounter allergic reactions and even malignant tumours in tattoos, and treating these conditions requires a nuanced approach. © 2017 S. Karger AG, Basel.

  12. Graphene Q-Switched Compact Yb:YAG Laser

    Czech Academy of Sciences Publication Activity Database

    Serres, J.M.; Jambunathan, Venkatesan; Mateos, X.; Loiko, P.; Lucianetti, Antonio; Mocek, Tomáš; Yumashev, K.; Petrov, V.; Griebner, U.; Aguilo, M.; Diaz, F.

    2015-01-01

    Roč. 7, č. 5 (2015), s. 1-8, č. článku 1503307. ISSN 1943-0655 R&D Projects: GA MŠk ED2.1.00/01.0027; GA MŠk EE2.3.20.0143; GA ČR GA14-01660S Grant - others:HILASE(XE) CZ.1.05/2.1.00/01.0027; OP VK 6(XE) CZ.1.07/2.3.00/20.0143 Institutional support: RVO:68378271 Keywords : graphene * saturable absorber * Q-switched laser Subject RIV: BH - Optics, Masers, Laser s OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 2.177, year: 2015

  13. Narrow Q-switching pulse width and low mode-locking repetition rate Q-switched mode locking with a new coupled laser cavity

    International Nuclear Information System (INIS)

    Peng, J Y; Zheng, Y; Shen, J P; Shi, Y X

    2013-01-01

    An original diode-pumped Q-switched and mode-locked solid state Nd:GdVO 4 laser is demonstrated. The laser operates with double saturable absorbers and a new coupled laser cavity. The Q-switching envelope width is compressed to be about 15 ns and the mode-locking repetition rate is as low as 90 MHz. (paper)

  14. Passive Fe2+ : ZnSe single-crystal Q switch for 3-mu m lasers

    NARCIS (Netherlands)

    Voronov, AA; Kozlovskii, [No Value; Korostelin, YV; Podmar'kov, YP; Polushkin, VG; Frolov, MP

    Passive Q-switching of 3-mu m lasers with the help of a Fe2+ : ZnSe single crystal is demonstrated. The 6-mJ, 50-ns giant pulses are obtained from a 2.9364-mu m Er : YAG laser by using this passive Q switch.

  15. Combination of CO2 and Q-switched Nd:YAG lasers is more effective than Q-switched Nd:YAG laser alone for eyebrow tattoo removal.

    Science.gov (United States)

    Radmanesh, Mohammad; Rafiei, Zohreh

    2015-04-01

    The eyebrow tattoo removal using Q-switched lasers is usually prolonged. Other modalities may be required to enhance the efficacy and shorten the treatment course. To compare the efficacy of Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser alone versus combination of Q-switched Nd:YAG and Ultrapulse CO2 lasers for eyebrow tattoo removal after a single session. After local anesthesia, the right eyebrow of 20 patients was treated with Ultrapulse CO2 laser with the parameters of 4 J/cm(2) and 3.2 J/cm(2) for the first and the second passes. Both eyebrows were then treated with 1064-nm and 532-nm Q-switched Nd:YAG laser. The spot size and pulse duration were 3 mm and 5 nanoseconds for both wavelengths, and the fluence was 7 J/cm(2) for 1064 nm and 3 J/cm (2) for 532 nm. The side treated with combination of Q-switched Nd:YAG and CO2 lasers improved 75-100% in 6 of 20 patients versus only 1 of 20 in the side treated with Q-switched Nd:YAG alone. Similarly, the right side in 13 of 20 patients showed more than 50% improvement with combination therapy versus the left side (the monotherapy side), where only 6 of 20 cases showed more than 50% improvement. The Mann-Whitney test was 2.85 for the right side and 1.95 for the left side (P value = 0.007). Using Ultra pulse CO2 laser enhances the efficacy of Q-switched Nd:YAG laser in eyebrow tattoo removal.

  16. Synchronisation of a femtosecond laser and a Q-switched laser to within 50 ps

    International Nuclear Information System (INIS)

    Katin, E V; Lozhkarev, V V; Palashov, O V; Khazanov, E A

    2003-01-01

    A Nd:YLF laser emitting 2-ns pulses synchronised with a femtosecond Cr:forsterite laser is built. The pulse duration and synchronisation are ensured by two Pockels cells, in which voltage pulses are synchronised with the femtosecond laser by fast emitter-coupled logic elements. One of the Pockels cells ensures Q-switching, while the other cuts a short pulse from a 15-ns Q-switched pulse. The experimental results show that the two-step scheme proposed for synchronisation of a Q-switched laser and a passively mode-locked laser provides quite simple and reliable synchronisation of these lasers with a jitter of a few tens of picoseconds. (control of laser radiation parameters)

  17. Passively synchronized dual-wavelength Q-switched lasers

    DEFF Research Database (Denmark)

    Janousek, Jiri; Tidemand-Lichtenberg, Peter; Mortensen, Jesper Liltorp

    We present a simple and efficient way of generating synchronized Q-switched pulses at wavelengths hundreds of nanometers apart. This principle can result in new pulsed all-solid-state light sources at new wavelengths based on SFG.......We present a simple and efficient way of generating synchronized Q-switched pulses at wavelengths hundreds of nanometers apart. This principle can result in new pulsed all-solid-state light sources at new wavelengths based on SFG....

  18. Q-switched oscillation in thulium-doped fiber lasers using preloaded dynamic microbending technique

    Science.gov (United States)

    Sakata, H.; Takahashi, N.; Ushiro, Y.

    2018-01-01

    We demonstrate Q-switched pulse generation in thulium-doped fiber lasers by introducing piezoelectric-driven microbend with preloaded stress. We employed a pair of corrugated chips each attached on piezoelectric actuators (PAs) to clamp the fiber in a ring laser resonator. The thulium-doped fiber is pumped by a laser diode emitting at 1.63 μm and generates the Q-switched laser pulses at around 1.9 μm by switching off the PAs. The laser pulse performance is improved by optimizing the preload and switch-off period for the PAs. The Q-switched pulses with a peak power of 2.8 W and a pulsewidth of 900 ns are observed for a launched pump power of 161 mW. We expect that the in-fiber Q-switching technique will provide efficient laser systems for environmental sensing and medical applications.

  19. Mathematical modeling of a passively Q-switched diode laser

    International Nuclear Information System (INIS)

    Abdul Ghani, B.; Hammadi, M.

    2009-11-01

    A mathematical model describing the dynamic emission of the intracavity frequency doubling (IFD) of a gain-switched InGaAs/GaAs/KTP and a gain-switched mode-locked two-sections tapered ridge-waveguide InGaAs/GaAs diode laser has been presented. The IFD of a gain-switched and a gain-switched mode-locked two-sections diode laser is modeled where one section is electrically pumped to proved gain while the second section is unpumped (reverse biased) to provide a saturable absorber. (author)

  20. Q-switched Ho:YLF laser pumped by a Tm:GdVO4 laser.

    CSIR Research Space (South Africa)

    Esser, MJD

    2009-06-01

    Full Text Available The authors have, through careful analysis of spectroscopic data, designed and demonstrated a diode-end-pumped, quasicontinuous wave Tm:GdVO4 laser operating at 1892 nm in order to pump a Q-switched Ho:YLF laser. The Ho:YLF maximum output energy...

  1. Q-Switched High Power Single Frequency 2 Micron Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Accurate measurement of atmospheric parameters with high resolution needs advanced lasers. In this SBIR program we propose to develop innovative Q-switched high...

  2. Treatment of Large Bulla Formation after Tattoo Removal with a Q-Switched Laser

    Science.gov (United States)

    Kartono, Francisca; Desai, Alpesh; Kaur, Ravneet R.; Desai, Tejas

    2010-01-01

    Widely considered the gold standard treatment option for tattoo removal, the use of Q-switched lasers may very rarely result in the formation of large bulla. While very disconcerting to patients, these lesions are easily managed and, with proper care, heal quickly with no long-term consequences. The authors present three cases of patients who had bullous reactions shortly after receiving Q-switched laser treatment of tattoo ink. Bullous formation in all three patients was treated successfully. PMID:20725537

  3. A STUDY OF SOLID STATE LASER PASSIVE OPTICAL Q-SWITCHING OPERATION REGIME (Part 1

    Directory of Open Access Journals (Sweden)

    Ion LĂNCRĂNJAN

    2009-09-01

    Full Text Available This paper is the first of a four series treating, theoretically with experimental comparison, the issue of solid state laser passive optical Q-switching regime. In this first paper the technique of solid state lasers passive optical Q-switching is numerically investigated considering the case of longitudinally and transversally uniform photon, population inversion and absorption centres densities. The coupled differential equations defining photon, population inversion and absorption centres densities are numerically solved being the basis of passively optical Q-switched laser functional simulation. The numerical simulations are performed using the several software packages, mostly SCILAB programs. The developed SCILAB programs can be used for a large range of saturable absorption centre and active media parameters, mainly the initial (low signal optical transmittance of the passive optical Q-switch. The developed FORTRAN and SCILAB programs can be applied for passively Q-switched solid state lasers of several types emitting at several NIR wavelengths, in domain 1 ÷ 2 μm. For validating the numerical simulation results are compared with The results of the numerical simulation are compared with experimentally obtained ones, in the case of a LiF:F2- passively Q-switched Nd:YAG. A good agreement between the two kinds of results is observed.

  4. Laser-tissue interaction in tattoo removal by q-switched lasers.

    Science.gov (United States)

    Barua, Shyamanta

    2015-01-01

    Q-switched (QS) lasers are widely considered the gold standard for tattoo removal, with excellent clinical results, impressive predictability, and a good safety profile. The generation of giant pulses by the method of Q-switching is responsible for the unique laser-tissue interaction that is seen in tattoo removal by QS lasers. The QS lasers work by impaction and dissolution of the tattoo pigments. Mechanical fragmentation of the tattoo pigments encased in intracellular lamellated organelles followed by their phagocytosis by macrophages is thought to be the major event in the clearance of pigments by QS lasers. A few novel techniques have been tried in recent times to hasten the clearance of tattoo pigments.

  5. Metal impurity injection into DIVA plasmas with a Q-switched laser beam

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Nagami, Masayuki; Sengoku, Seio; Kumagai, Katsuaki

    1978-08-01

    Metal impurity injection into DIVA plasmas with a Q-switched ruby laser beam is described. Metal materials used are aluminium and gold. The Q-switched laser beam is incident onto a thin metal film thickness about 0.2 μm coated on pyrex glass plate surface. The metal film is vaporized by the laser beam and injected into DIVA plasma. The laser-beam injection method has advantages of sharp profile of vaporized metal, easy control of vaporized metal quantity and injection rate control of metal vapor. (author)

  6. High repetition rate, high energy, actively Q-switched all-in-fiber laser

    Science.gov (United States)

    Lecourt, J. B.; Bertrand, A.; Guillemet, S.; Hernandez, Y.; Giannone, D.

    2010-05-01

    We report an actively Q-switched Ytterbium-doped all-in-fibre laser delivering 10ns pulses with high repetition rate (from 100kHz to 1MHz). The laser operation has been validated at three different wavelengths (1040, 1050 and 1064nm). The laser can deliver up to 20Watts average power with an high beam quality (M2 = 1).

  7. Nanosecond Q-switched operation of coupled Yb and Tm fibre lasers

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, Yuen H [Laser Photonics Research Group, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Qamar, Fadi [Laser Photonics Research Group, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); King, Terence A [Laser Photonics Research Group, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Ko, Do-Kyeong [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-Gu, Gwangju 500-712 (Korea, Republic of); Lee, Jongmin [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-Gu, Gwangju 500-712 (Korea, Republic of)

    2005-05-07

    A small scale coupled Yb-silica and Tm-silica fibre laser system is described with output at 1.9 {mu}m and with Q-switching using an acousto-optic modulator and also by mechanical optical modulation. The Yb-fibre laser pump source exhibited strong self-pulsation with high-intensity pulses due to stimulated Brillouin scattering. But regular Q-switched pulses were generated from the Tm-fibre laser with an energy of {approx}2.4 {mu}J and duration (FWHM) of {approx}280 ns for modulation frequencies of 1-20 kHz when using acousto-optic modulation. The main effects that limit the Q-switched pulse peak power are the onset of gain-switched pulsing during the low-Q state and strong pump excited state absorption.

  8. Passive synchronized Q-switching between a quasi-three-level and a four-level laser

    DEFF Research Database (Denmark)

    Cheng, Haynes Pak Hay; Tidemand-Lichtenberg, Peter; Jensen, Ole Bjarlin

    2011-01-01

    Synchronized Q-switching between quasi-three-level and four-level lasers is interesting for sum-frequency generation into the blue and ultraviolet. We report, for the first time, stable synchronized Q-switching between a quasi-three-level laser at 946 nm and a four-level laser at 1064 nm in an all...

  9. Passive Q switching of a solar-pumped Nd:YAG laser.

    Science.gov (United States)

    Lando, M; Shimony, Y; Noter, Y; Benmair, R M; Yogev, A

    2000-04-20

    Passive Q switching is a preferable choice for switching the Q factor of a solar-pumped laser because it requires neither a driver nor an electrical power supply. The superior thermal characteristics and durability of Cr(4+):YAG single crystals as passive Q switches for lamp and diode-pumped high-power lasers has been demonstrated. Here we report on an average power of 37 W and a switching efficiency of 80% obtained by use of a solar-pumped Nd:YAG laser Q switched by a Cr(4+):YAG saturable absorber. Concentration of the pumping solar energy on the laser crystal was obtained with a three-stage concentrator, composed of 12 heliostats, a three-dimensional compound parabolic concentrator (CPC) and a two-dimensional CPC. The water-cooled passive Q switch also served as the laser rear mirror. Repetition rates of as much as 50 kHz, at pulse durations between 190 and 310 ns (FWHM) were achieved. From the experimental results, the saturated single-pass power absorption of the Cr(4+):YAG device was estimated as 3 ? 1%.

  10. Design of a high-power Nd:YAG Q-switched laser cavity

    Science.gov (United States)

    Singh, Ikbal; Kumar, Avinash; Nijhawan, O. P.

    1995-06-01

    An electro-optically Q-switched Nd:YAG laser resonator that uses two end prisms placed orthogonally perpendicular to each other has been designed. This configuration improves the stability of the resonator and does not alter the characteristics of the electro-optical Q switch. The outcoupling ratio of the cavity is optimized by a change in the azimuthal angle of a phase-matched Porro prism placed at one end of the cavity. The prism placed at the other end of the cavity is designed so that it introduces a phase change of Pi , regardless of its orientation and index of refraction, resulting in a more efficient and stable cavity.

  11. Compact frequency-modulation Q-switched single-frequency fiber laser at 1083 nm

    International Nuclear Information System (INIS)

    Zhang, Yuanfei; Feng, Zhouming; Xu, Shanhui; Mo, Shupei; Yang, Changsheng; Li, Can; Gan, Jiulin; Chen, Dongdan; Yang, Zhongmin

    2015-01-01

    A compact frequency-modulation Q-switched single-frequency fiber laser is demonstrated at 1083 nm. The short linear resonant cavity consists of a 12 mm long homemade Yb 3+ -doped phosphate fiber and a pair of fiber Bragg gratings (FBGs) in which the Q-switching and the frequency excursion is achieved by a tensile-induced period modulation. Over 375 MHz frequency-tuning range is achieved with a modulation frequency varying from tens to hundreds of kilohertz. The highest peak power of the output pulse reaching 6.93 W at the repetition rate of 10 kHz is obtained. (paper)

  12. A Q-Switched Erbium-Doped Fiber Laser with a Carbon Nanotube Based Saturable Absorber

    International Nuclear Information System (INIS)

    Harun, S. W.; Ismail, M. A.; Ahmad, F.; Ismail, M. F.; Nor, R. M.; Zulkepely, N. R.; Ahmad, H.

    2012-01-01

    We demonstrate a simple, compact and low cost Q-switched erbium-doped fiber laser (EDFL) using single-wall carbon nanotubes (CNTs) as a saturable absorber for possible applications in metrology, sensing, and medical diagnostics. The EDFL operates at around 1560 nm with repetition rates of 16.1 kHz and 6.4 kHz with saturable absorbers SA1 and SA2 at a pump power of 120 mW. The absorbers are constructed by optically driven deposition and normal deposition techniques. It is observed that the optical deposition method produces a Q-switched EDFL with a lower threshold of 70 mW and better Q-switching performance compared to that of the normal deposition method. The EDFL also has pulse energy of 90.3 nJ and pulse width of 11.6 μs at 120 mW pump power

  13. Compact self-Q-switched Tm:YLF laser at 1.91 μm

    Science.gov (United States)

    Zhang, B.; Li, L.; He, C. J.; Tian, F. J.; Yang, X. T.; Cui, J. H.; Zhang, J. Z.; Sun, W. M.

    2018-03-01

    We report self-Q-switching operation in a diode-pumped Tm:YLF bulk laser by exploiting saturable re-absorption under the quasi-three-level regime. Robust self-Q-switched pulse output at 1.91 μm in fundamental mode is demonstrated experimentally with 1.5 at.% doped Tm:YLF crystal. At maximum absorbed pump power of 4.5 W, the average output power and pulse energy are obtained as high as 610 mW and 29 μJ, respectively, with the corresponding slope efficiency of 22%. Pulse repetition rate is tunable in the range of 3-21 kHz with changing the pump power. The dynamics of self-Q-switching of Tm:YLF laser are discussed with the help of a rate equation model showing good agreement with the experiment. The compact self-Q-switched laser near 2 μm has potential application in laser radar systems for accurate wind velocity measurements.

  14. Optimization of an intracavity Q-switched solid-state second order Raman laser

    Science.gov (United States)

    Chen, Zhiqiong; Fu, Xihong; Peng, Hangyu; Zhang, Jun; Qin, Li; Ning, Yongqiang

    2017-01-01

    In this paper, the model of an intracavity Q-switched second order Raman laser is established, the characteristics of the output 2nd Stokes are simulated. The dynamic balance mechanism among intracavity conversion rates of stimulated emission, first order Raman and second order Raman is obtained. Finally, optimization solutions for increasing output 2nd Stokes pulse energy are proposed.

  15. Optimization of end-pumped, actively Q-switched quasi-III-level lasers.

    Science.gov (United States)

    Jabczynski, Jan K; Gorajek, Lukasz; Kwiatkowski, Jacek; Kaskow, Mateusz; Zendzian, Waldemar

    2011-08-15

    The new model of end-pumped quasi-III-level laser considering transient pumping processes, ground-state-depletion and up-conversion effects was developed. The model consists of two parts: pumping stage and Q-switched part, which can be separated in a case of active Q-switching regime. For pumping stage the semi-analytical model was developed, enabling the calculations for final occupation of upper laser level for given pump power and duration, spatial profile of pump beam, length and dopant level of gain medium. For quasi-stationary inversion, the optimization procedure of Q-switching regime based on Lagrange multiplier technique was developed. The new approach for optimization of CW regime of quasi-three-level lasers was developed to optimize the Q-switched lasers operating with high repetition rates. Both methods of optimizations enable calculation of optimal absorbance of gain medium and output losses for given pump rate. © 2011 Optical Society of America

  16. Microsecond pulsed optical parametric oscillator pumped by a Q-switched fiber laser

    NARCIS (Netherlands)

    Klein, M.E.; Adel, P.; Auerbach, M.; Fallnich, C.; Gross, P.; Boller, Klaus J.

    2003-01-01

    We report on what is to our knowledge the first optical parametric oscillator (OPO) pumped by microsecond pulses from a wavelength-tunable solid-state laser. The singly resonant OPO (SRO) is based on a periodically poled LiNbO3 crystal and pumped with 2.1-ms-long pulses from an actively Q-switched

  17. Hollow fiber optics with improved durability for high-peak-power pulses of Q-switched Nd:YAG lasers.

    Science.gov (United States)

    Matsuura, Yuji; Tsuchiuchi, Akio; Noguchi, Hiroshi; Miyagi, Mitsunobu

    2007-03-10

    To improve the damage threshold of hollow optical waveguides for transmitting Q-switched Nd:YAG laser pulses, we optimize the metallization processes for the inner coating of fibers. For silver-coated hollow fiber as the base, second, and third Nd:YAG lasers, drying silver films at a moderate temperature and with inert gas flow is found to be effective. By using this drying process, the resistance to high-peak-power optical pulse radiation is drastically improved for fibers fabricated with and without the sensitizing process. The maximum peak power transmitted in the fiber is greater than 20 MW. To improve the energy threshold of aluminum-coated hollow fibers for the fourth and fifth harmonics of Nd:YAG lasers, a thin silver film is added between the aluminum film and the glass substrate to increase adhesion of the aluminum coating. By using this primer layer, the power threshold improves to 3 MW for the fourth harmonics of a Q-switched Nd:YAG laser light.

  18. Diode-pumped Alexandrite laser with passive SESAM Q-switching and wavelength tunability

    Science.gov (United States)

    Parali, Ufuk; Sheng, Xin; Minassian, Ara; Tawy, Goronwy; Sathian, Juna; Thomas, Gabrielle M.; Damzen, Michael J.

    2018-03-01

    We report the first experimental demonstration of a wavelength tunable passively Q-switched red-diode-end pumped Alexandrite laser using a semiconductor saturable absorber mirror (SESAM). We present the results of the study of passive SESAM Q-switching and wavelength-tuning in continuous diode-pumped Alexandrite lasers in both linear cavity and X-cavity configurations. In the linear cavity configuration, pulsed operation up to 27 kHz repetition rate in fundamental TEM00 mode was achieved and maximum average power was 41 mW. The shortest pulse generated was 550 ns (FWHM) and the Q-switched wavelength tuning band spanned was between 740 nm and 755 nm. In the X-cavity configuration, a higher average power up to 73 mW, and obtained with higher pulse energy 6 . 5 μJ at 11.2 kHz repetition rate, in fundamental TEM00 mode with excellent spatial quality M2 < 1 . 1. The Q-switched wavelength tuning band spanned was between 775 nm and 781 nm.

  19. Depigmentation therapy with Q-switched Nd: YAG laser in universal vitiligo

    Directory of Open Access Journals (Sweden)

    Imran Majid

    2013-01-01

    Full Text Available Background: Any residual pigment left in patients of universal vitiligo is managed with topical treatments, cryotherapy, and lasers. Aim: The study aims to assess the efficacy and safety of Q-switched Nd: YAG laser in treating the residual pigmentation in patients with universal vitiligo. Materials and Methods: Fifteen patients of universal vitiligo with residual pigmentation on the face, hands, or feet, resistant to topical treatments, were treated with single or multiple sessions of Q-switched Nd: YAG laser treatment. Topical treatments were continued in between the laser sessions and the depigmentation achieved was monitored by clinical examination and repeat digital photographs. Response to the treatment was labelled as excellent if the residual pigment could be reduced by at least 90% while 50-90% resolution of pigmentation was labelled as a partial response. Adverse effects to the treatment offered were also monitored. Results: Thirteen of the 15 patients enrolled for the study showed an excellent response to the treatment offered. Two other patients showed a poor response with less than 50% resolution of pigmentation. The number of laser sessions needed at a particular site ranged from 1 to 3 and no patient was offered more than three sessions of laser treatment at any site. No significant adverse events were reported by any patient. Conclusions: Residual pigmentation in patients with universal vitiligo that does not respond to topical treatment options alone can be managed quite effectively with Q-switched Nd: YAG laser without any significant adverse effects.

  20. Self-Q-switched ytterbium-doped cladding-pumped fibre laser

    International Nuclear Information System (INIS)

    Grukh, Dmitrii A; Kurkov, Andrei S; Razdobreev, I M; Fotiadi, A A

    2002-01-01

    A self-Q-switched ytterbium-doped double-clad fibre laser is described. A samarium-doped fibre is used as a filter for protecting a pump source. A fibre coupler is employed to obtain a nonlinear feedback. The mechanism of pulse formation in the laser is considered, and the dependence of its output pulse on the coupler parameters is studied. (solitons and optical fibers)

  1. Ocular hazards of Q-switched near-infrared lasers

    Science.gov (United States)

    Lund, David J.; Edsall, Peter R.; Stuck, Bruce E.

    2003-06-01

    The threshold for laser-induced retinal damage in the rhesus eye was determined for wavelengths between 900 nm and 1300 nm. The laser source was a tunable Optical Parametric Oscillator (OPO) pumped by the 3rd harmonic of a Nd:YAG laser. The laser pulse duration was 3.5 ns. The wavelength dependence of the injury threshold is consistent with the prediction of a model based on the transmission of the preretinal ocular media, absorption in the retinal pigment epithelium, and variation of irradiance diameter resulting from chromatic aberration of the eye optics for wavelengths shorter than 1150 nm but was less consistent for longer wavelengths. The threshold for 24-hour observation was slightly lower than the threshold for 1-hour observation. These data form a basis for reexamination of the currently defined MPEs for wavelengths longer than 1100 nm.

  2. High average power 1314 nm Nd:YLF laser, passively Q-switched with V:YAG

    CSIR Research Space (South Africa)

    Botha, RC

    2013-03-01

    Full Text Available A 1314 nm Nd:YLF laser was designed and operated both CW and passively Q-switched. Maximum CW output of 10.4 W resulted from 45.2 Wof incident pump power. Passive Q-switching was obtained by inserting a V:YAG saturable absorber in the cavity...

  3. An injection seeded single frequency Nd:YAG Q-switched laser with precisely controllable laser pulse firing time

    Science.gov (United States)

    Wu, Frank F.; Khizhnyak, Anatoliy; Markov, Vladimir

    2010-02-01

    We have realized a single frequency Q-switched Nd:YAG laser with precisely controllable lasing time and thus enabled synchronization of multi-laser systems. The use of injection seeding to the slave ring oscillator results in unidirectional Q-switched laser oscillation with suppression of bidirectional Q-switched oscillation that otherwise would be initiated from spontaneous emission if the seeding laser is not present. Under normal condition, the cavity is high in loss during the pumping period; then a Pockels cell opens the cavity to form the pulse build up, with a second Pockels cell to perform cavity dumping, generating the Q-switched pulse output with optimized characteristics. The two Pockels cells can be replaced by a single unit if an adjustable gated electrical pulse is applied to the Pockels cell in which the pulse front is used to open the cavity and the falling edge to dump the laser pulse. Proper selection of the pump parameters and Pockels-cell gating enables operation of the system in a mode in which the Q-switched pulse can be formed only under the seeding condition. The advantage of the realized regime is in stable laser operation with no need in adjustment of the seeded light wavelength and the mode of the cavity. It is found that the frequency of the Q-switched laser radiation matches well to the injected seeded laser mode. By using two-stage amplifiers, an output energy better than 300 mJ has been achieved in MOPA configuration without active control of the cavity length and with pulse width adjustability from several nanoseconds to 20 ns. The Q-switched oscillator operates not only at precisely controlled firing time but also can be tuned over wide range. This will enable multi-laser systems synchronization and frequency locking down each other if necessary.

  4. Efficient 2-μm Tm:YAP Q-switched and CW lasers

    Science.gov (United States)

    Hays, A. D.; Cole, Brian; King, Vernon; Goldberg, Lew

    2018-02-01

    Highly efficient, diode pumped Tm:YAP lasers generating emission in the 1.85-1.94 μm range are demonstrated and characterized. Laser optical efficiencies of 51% and 45%, and electrical efficiencies of 31% and 25% are achieved under CW and Q-switched operation, respectively. Laser performance was characterized for maximum average powers up to 20W with various cavity configurations, all using an intra-cavity lens to compensate for thermal lensing in the Tm:YAP crystal. Q-switched lasers incorportating a Cr:ZnS saturable absorber (SA), resonant mechanical mirror scanner, or acousto-optic modulator were characterized. To enable higher average output powers, measurements of the thermal lens were conducted for the Tm:YAP crystal as a function of pump power and were compared to values predicted by a finiteelement- analysis (FEA) thermal-optical model of the Tm:YAP crystal. A resonator model is developed to incorporate this calculated thermal lens and its effect on laser performance. This paper will address approaches for improving the performance of Tm:YAP lasers, and means for achieving increased average output powers while maintaining high optical efficiency for both SA and mechanical Q-switching.

  5. Black phosphorus saturable absorber for Q-switched Er:YAG laser at 1645 nm

    Science.gov (United States)

    Guo, Lei; Li, Tao; Zhang, Shuaiyi; Wang, Mingjian; Yang, Kejian; Fan, Mingqi; Zhao, Shengzhi; Li, Ming

    2018-03-01

    A Q-switched Er:YAG solid-state laser at 1645 nm based on black phosphorus (BP) saturable absorbers (SAs) was demonstrated firstly to our knowledge. The BP-SA was fabricated by drop-casting BP nanoplatelets dispersion on a YAG substrate and corresponding saturable absorption properties were characterized at 1.6 μm. By employing as-prepared BP-SAs, stable Q-switched laser operations were achieved with a pulse width of 2.8 μs and a repetition rate of 34 kHz, corresponding to the average output power of 0.33 W. The results verify that BP-SAs have great potential for pulsed 1.6 μm lasers.

  6. Self-Q-switching behavior of erbium-doped tellurite microstructured fiber lasers

    International Nuclear Information System (INIS)

    Jia, Zhi-Xu; Yao, Chuan-Fei; Kang, Zhe; Qin, Guan-Shi; Qin, Wei-Ping; Ohishi, Yasutake

    2014-01-01

    We reported self-Q-switching behavior of erbium-doped tellurite microstructured fiber (EDTMF) lasers and further demonstrated a self-Q-switched EDTMF laser with a high repetition rate of more than 1 MHz. A 14 cm EDTMF was used as the gain medium. Upon a pump power of ∼705 mW at 1480 nm, output pulses with a lasing wavelength of ∼1558 nm, a repetition rate of ∼1.14 MHz, and a pulse width of ∼282 ns were generated from the fiber by employing a linear cavity. The maximum output power was ∼316 mW and the slope efficiency was about 72.6% before the saturation of the laser power. Moreover, the influence of the fiber length on laser performances was investigated. The results showed that self-Q-switching behavior in our experiments was caused by the re-absorption originated from the ineffectively pumped part of the active fiber.

  7. Vibrating mirror system suitable for q-switching large-aperture lasers

    Energy Technology Data Exchange (ETDEWEB)

    Beckwith, P.J.

    1977-11-01

    Resonant vibrating mirrors provide a convenient means of Q-switching a laser, but large-aperture versions require careful design if the drive power is not to become excessive. This report outlines the design principles involved in the optimisation of moving-iron galvanometer drivers, and describes a prototype device with an aperture of 40 mm x 80 mm which is capable of beam deflections of + or - 40 mrad at 800 Hz. Some suggestions are made concerning more refined designs.

  8. Stabilization of the quasi-periodic motion of a Q-switched Nd:YAG laser

    International Nuclear Information System (INIS)

    Kim, Chil-Min; Rim, Sunghwan; Kye, Won-Ho; Kim, Jeong-Moog; Lee, Kang-Soo

    2004-01-01

    We have developed a stabilization method of quasi-periodicity based on a return map. The method is explained in the forced Van der Pol oscillator, and applied experimentally to a quasi-periodic output of a Q-switched Nd:YAG laser. Even though the attractors have no unstable periodic orbit, we were able to stabilize them to an arbitrarily chosen orbit by targeting the trajectory into it

  9. High average power Q-switched 1314 nm two-crystal Nd:YLF laser

    CSIR Research Space (South Africa)

    Botha, RC

    2015-02-01

    Full Text Available . 40, No. 4 / OPTICS LETTERS High average power Q-switched 1314 nm two-crystal Nd:YLF laser R. C. Botha,1,2,* W. Koen,3 M. J. D. Esser,3,4 C. Bollig,3,5 W. L. Combrinck,1,6 H. M. von Bergmann,2 and H. J. Strauss3 1HartRAO, P.O. Box 443...

  10. Efficient energy extraction from a diode-pumped Q-switched Tm,Ho:YLiF4 laser

    Science.gov (United States)

    Mcguckin, B. T.; Menzies, R. T.; Hemmati, H.

    1991-01-01

    The operation of a diode-laser pumped thulium, holmium yttrium-lithium-fluoride laser (Tm,Ho:YLF) in Q-switched mode is reported. Output energies of 200 microjoules in pulses of 22 ns duration are recorded at Q-switch frequencies commensurate with an effective upper laser level lifetime of 6 ms. This lifetime is appreciably longer than that observed in other hosts permitting stored energy extraction of 64 percent, close to the projected maximum performance from these materials.

  11. Q-switched operation with Fox-Smith-Michelson laser cavity

    International Nuclear Information System (INIS)

    Huang, X; Huang, L; Gong, M

    2008-01-01

    A new kind of three-mirror composite cavity, Fox-Smith-Michelson cavity has been configured. This laser cavity is capable of high power output, owing to the low threshold of Michelson cavity. Also, thanks to the mode selection function of Fox-Smith cavity, stable pulses at high repetition rate can be generated. In our experiment, 15.54 W CW output at 1064 nm has been achieved, with an optic-to-optic conversion efficiency of 42.2%. At the Q-switching repetition rate of 100 kHz, the average output power is 11.92 W, with an optic-to-optic conversion efficiency of 38.2%. For Q-switching frequency from 30 kHz to 100 kHz, the pulse width variation is below 4.4% and the amplitude variation is below 4.8%

  12. Development of laser marking system with electro-optic Q-switch

    International Nuclear Information System (INIS)

    Kim, Cheol Jung; Kim, Jeong Moog; Kim, Kwang Suk; Park, Seung Kyu; Baik, Sung Hoon.

    1995-11-01

    We developed a high repetition electro-optic Q switch Nd:YAG laser and scan system for laser marking. We localized the scan mirrors and their mounts. We made the database for the optical properties of commercial flat-field lenses with our optics design software. We fabricated the detailed network between the galvanometer based beam scanning system and the laser generator. To accelerate the commercialization by the joint company, the training and transfer of technology were pursued in the joint participation by company researchers from the early stage. (author). 8 refs., 6 tabs., 27 figs

  13. Development of laser marking system with electro-optic Q-switch

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol Jung; Kim, Jeong Moog; Kim, Kwang Suk; Park, Seung Kyu; Baik, Sung Hoon

    1995-11-01

    We developed a high repetition electro-optic Q switch Nd:YAG laser and scan system for laser marking. We localized the scan mirrors and their mounts. We made the database for the optical properties of commercial flat-field lenses with our optics design software. We fabricated the detailed network between the galvanometer based beam scanning system and the laser generator. To accelerate the commercialization by the joint company, the training and transfer of technology were pursued in the joint participation by company researchers from the early stage. (author). 8 refs., 6 tabs., 27 figs.

  14. High resolution laser micro sintering / melting using q-switched and high brilliant laser radiation

    Science.gov (United States)

    Exner, H.; Streek, A.

    2015-03-01

    Since the discovery of selective laser sintering/melting, numerous modifications have been made to upgrade or customize this technology for industrial purposes. Laser micro sintering (LMS) is one of those modifications: Powders with particles in the range of a few micrometers are used to obtain products with highly resolved structures. Pulses of a q-switched laser had been considered necessary in order to generate sinter layers from the micrometer scaled metal powders. LMS has been applied with powders from metals as well as from ceramic and cermet feedstock's to generate micro parts. Recent technological progress and the application of high brilliant continuous laser radiation have now allowed an efficient laser sintering/melting of micrometer scaled metal powders. Thereby it is remarkable that thin sinter layers are generated using high continuous laser power. The principles of the process, the state of the art in LMS concerning its advantages and limitations and furthermore the latest results of the recent development of this technology will be presented. Laser Micro Sintering / Laser Micro Melting (LMM) offer a vision for a new dimension of additive fabrication of miniature and precise parts also with application potential in all engineering fields.

  15. Nanosecond-pulsed Q-switched Nd:YAG laser at 1064 nm with a gold nanotriangle saturable absorber

    Science.gov (United States)

    Chen, Xiaohan; Li, Ping; Dun, Yangyang; Song, Teng; Ma, Baomin

    2018-06-01

    Gold nanotriangles (GNTs) were successfully employed as a saturable absorber (SA) to achieve passively Q-switched lasers for the first time. The performance of the Q-switched Nd:YAG laser at 1064 nm has been systematically investigated. The corresponding shortest pulsewidth, the threshold pump power and the maximum Q-switched average output power were 275.5 ns, 1.37 W, and 171 mW, respectively. To our knowledge, this is the shortest pulsewidth and the lowest threshold in a passively Q-switched laser at approximately 1.1 µm based on a gold nanoparticle SA (GNPs-SA). Our experimental results proved that the GNTs-SA can be used as a promising saturable absorber for nanosecond-pulsed lasers.

  16. Submicrosecond Q-Switching Er-Doped All-Fiber Ring Laser Based on Black Phosphorus

    Directory of Open Access Journals (Sweden)

    Yao Cai

    2017-01-01

    Full Text Available Black phosphorus (BP, a new two-dimensional (2D material, has been deeply developed for extensive applications in electronics and optoelectronics due to its similar physical structure to graphene and thickness dependent direct band gap. Here, we demonstrated a submicrosecond passive Q-switching Er-doped fiber laser with BP as saturable absorber (SA. The BP saturable absorber was fabricated by mechanical exfoliation method. By taking full advantage of the ultrafast relaxation time of BP-SA and careful design of compact ring cavity, we obtained stable Q-switching pulses output with a shortest duration as narrow as 742 ns. With increasing the pump power, the pulse repetition rate accreted gradually almost linearly from 9.78 to 61.25 kHz, and the pulse duration declined rapidly at lower pump power regime and retained approximate stationary at higher pump power regime from 3.05 to 0.742 μs. The experimental results indicate that BP-SA can be an effective SA for nanosecond Q-switching pulse generation.

  17. Experimental study of a Q-switched ytterbium-doped double-clad fiber laser

    International Nuclear Information System (INIS)

    Anzueto S, G.; Estudillo A, M.; Martinez R, A.; Torres G, I.; Selvas A, R.

    2008-01-01

    We report an experimental characterization of a Q-switched operation of an all-fiber laser using , 30 m of a double-clad ytterbium-doped fiber spliced to a piece of single-mode un-doped holey fiber. Loss modulation in the splicing point between the active and un-doped fiber due to a substantial coupling of light into lossy cladding modes stimulates pulsed operation of the fiber laser. Pulse energy of ∼2.5 μJ was estimated and the repetition rate was measured in the range of 4-16 KHz. (Author)

  18. Graphene Oxide-Based Q-Switched Erbium-Doped Fiber Laser

    International Nuclear Information System (INIS)

    Yap, Y. K.; Harun, S. W.; Ahmad, H.; Huang, N. M.

    2013-01-01

    We demonstrate a pulsed ring erbium-doped fiber laser based on graphene oxide (GO), employing a simplified Hummer's method to synthesize the GO via chemical oxidation of graphite flakes at room temperature. By dipping a fiber ferrule end face onto the GO suspension, GO is successfully coated onto the end face, making it a simple saturable absorption device. A stable Q-switched pulsed fiber laser is achieved with a low pump threshold of 9.5 mW at 980 nm. The pulse repetition rate ranges from 16.0 to 57.0 kHz. The pulse width and the pulse energy are studied and discussed

  19. Q-switched all-fiber laser with short pulse duration based on tungsten diselenide

    Science.gov (United States)

    Li, Wenyi; OuYang, Yuyi; Ma, Guoli; Liu, Mengli; Liu, Wenjun

    2018-05-01

    Fiber lasers are widely used in industrial processing, sensing, medical and communications applications due to their simple structure, good stability and low cost. With the rapid development of fiber lasers and the sustained improvement of industrial laser quality requirements, researchers in ultrafast optics focus on how to get laser pulses with high output power and narrow pulse duration. Q-switched technology is one of the most effective techniques to generate ultrashort pulses. In this paper, a tungsten diselenide saturable absorber with 16.82% modulation depth is prepared by chemical vapor deposition. Experimental results show that when the pump power changes from 115.7 mW to 630 mW, the all-fiber laser can achieve a stable Q-switched pulse output. The repetition rate of the output pulse varies from 80.32 kHz to 204.2 kHz, the pulse duration is 581 ns, the maximum output power is 17.1 mW and the maximum pulse energy is 83.7 nJ. Results in this paper show that tungsten diselenide can be applied to ultrafast optics, which is a kind of saturable absorption material with excellent properties.

  20. A high-peak-power passively Q-switched composite variable-cut vanadate laser

    International Nuclear Information System (INIS)

    Sirotkin, A A

    2014-01-01

    We present laser sources based on a novel method of controlling spectral parameters in diode-pumped vanadate lasers. Angular dependences of the luminescence intensity of Stark transitions at the 4F3/2‒4I11/2 transition in vanadate crystals are investigated. The operation of diode-pumped passively Q-switched composite variable-cut (θ = var, φ = 0) YVO 4 –Nd 3+  : YVO 4 lasers with Cr 4+  : YAG saturable absorber is demonstrated (the narrowest pulse of 2 ns with the highest peak power of 24.3 kW). In the experiment, an efficient self-Raman laser was realized, based on the multifunctional variable-cut (θ = 25°, φ = 0) YVO 4 –Nd 3+  : YVO 4 laser crystal with the passive Q-switched. (letters)

  1. Intraoperative localized urticarial reaction during Q-switched Nd:YAG laser tattoo removal.

    Science.gov (United States)

    Wilken, Reason; Ho, Derek; Petukhova, Tatyana; Jagdeo, Jared

    2015-03-01

    Q-switched lasers, such as the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, are the gold standard for tattoo removal. Allergy to tattoo pigment is well-documented, but adverse allergic reactions during or shortly after laser tattoo removal are rare with few reports in the medical literature. Here we describe an intraoperative, localized urticarial reaction that developed during treatment of a tattoo using a 1064-nm Nd:YAG laser. As laser tattoo removal becomes increasingly popular amongst our patients, it is important for dermatologists to be aware of urticarial allergic reactions as well as their management. We outline our recommendations for medical management of this condition and hope that these guidelines will facilitate patient care by dermatologists who encounter this immune skin reaction to laser tattoo removal

  2. Resonantly diode-pumped continuous-wave and Q-switched Er:YAG laser at 1645 nm.

    Science.gov (United States)

    Chang, N W H; Simakov, N; Hosken, D J; Munch, J; Ottaway, D J; Veitch, P J

    2010-06-21

    We describe an efficient Er:YAG laser that is resonantly pumped using continuous-wave (CW) laser diodes at 1470 nm. For CW lasing, it emits 6.1 W at 1645 nm with a slope efficiency of 36%, the highest efficiency reported for an Er:YAG laser that is pumped in this manner. In Q-switched operation, the laser produces diffraction-limited pulses with an average power of 2.5 W at 2 kHz PRF. To our knowledge this is the first Q-switched Er:YAG laser resonantly pumped by CW laser diodes.

  3. Pigmented guinea pig skin irradiated with Q-switched ruby laser pulses. Morphologic and histologic findings

    Energy Technology Data Exchange (ETDEWEB)

    Dover, J.S.; Margolis, R.J.; Polla, L.L.; Watanabe, S.; Hruza, G.J.; Parrish, J.A.; Anderson, R.R.

    1989-01-01

    Q-switched ruby laser pulses cause selective damage to cutaneous pigmented cells. Repair of this selective damage has not been well described. Therefore, using epilated pigmented and albino guinea pig skin, we studied the acute injury and tissue repair caused by 40-ns, Q-switched ruby laser pulses. Gross observation and light and electron microscopy were performed. No specific changes were evident in the albino guinea pigs. In pigmented animals, with radiant exposures of 0.4 J/cm2 or greater, white spots confined to the 2.5-mm exposure sites developed immediately and faded over 20 minutes. Delayed depigmentation occurred at seven to ten days, followed by full repigmentation by four to eight weeks. Regrowing hairs in sites irradiated at and above 0.4 J/cm2 remained white for at least four months. Histologically, vacuolation of pigment-laden cells was seen immediately in the epidermis and the follicular epithelium at exposures of 0.3 J/cm2 and greater. Melanosomal disruption was seen immediately by electron microscopy at and above 0.3 J/cm2. Over the next seven days, epidermal necrosis was followed by regeneration of a depigmented epidermis. By four months, melanosomes and melanin pigmentation had returned; however, hair follicles remained depigmented and devoid of melanocytes. This study demonstrates that selective melanosomal disruption caused by Q-switched ruby laser pulses leads to transient cutaneous depigmentation and persistent follicular depigmentation. Potential exists for selective treatment of pigmented epidermal and dermal lesions with this modality.

  4. Melanosomes are a primary target of Q-switched ruby laser irradiation in guinea pig skin

    Energy Technology Data Exchange (ETDEWEB)

    Polla, L.L.; Margolis, R.J.; Dover, J.S.; Whitaker, D.; Murphy, G.F.; Jacques, S.L.; Anderson, R.R.

    1987-09-01

    The specific targeting of melanosomes may allow for laser therapy of pigmented cutaneous lesions. The mechanism of selective destruction of pigmented cells by various lasers, however, has not been fully clarified. Black, brown, and albino guinea pigs were exposed to optical pulses at various radiant exposure doses from a Q-switched, 40 nsec, 694 nm ruby laser. Biopsies were analyzed by light and electron microscopy (EM). Albino animals failed to develop clinical or microscopic evidence of cutaneous injury after irradiation. In both black and brown animals, the clinical threshold for gross change was 0.4 J/cm2, which produced an ash-white spot. By light microscopy, alterations appeared at 0.3 J/cm2 and included separation at the dermoepidermal junction, and the formation of vacuolated epidermal cells with a peripheral cytoplasmic condensation of pigment. By EM, enlarged melanosomes with a central lucent zone were observed within affected epidermal cells at 0.3 J/cm2. At 0.8 and 1.2 J/cm2, individual melanosomes were more intensely damaged and disruption of melanosomes deep in the hair papillae was observed. Dermal-epidermal blisters were formed precisely at the lamina lucida, leaving basal cell membranes and hemidesmosomes intact. Possible mechanisms for melanosomal injury are discussed. These observations show that the effects of the Q-switched ruby laser are melanin-specific and melanin-dependent, and may be useful in the selective destruction of pigmented as well as superficial cutaneous lesions.

  5. High-power planar dielectric waveguide lasers

    International Nuclear Information System (INIS)

    Shepherd, D.P.; Hettrick, S.J.; Li, C.; Mackenzie, J.I.; Beach, R.J.; Mitchell, S.C.; Meissner, H.E.

    2001-01-01

    The advantages and potential hazards of using a planar waveguide as the host in a high-power diode-pumped laser system are described. The techniques discussed include the use of proximity-coupled diodes, double-clad waveguides, unstable resonators, tapers, and integrated passive Q switches. Laser devices are described based on Yb 3+ -, Nd 3+ -, and Tm 3+ -doped YAG, and monolithic and highly compact waveguide lasers with outputs greater than 10 W are demonstrated. The prospects for scaling to the 100 W level and for further integration of devices for added functionality in a monolithic laser system are discussed. (author)

  6. Effect of Q-switched Laser Surface Texturing of Titanium on Osteoblast Cell Response

    Science.gov (United States)

    Voisey, K. T.; Scotchford, C. A.; Martin, L.; Gill, H. S.

    Titanium and its alloys are important biomedical materials. It is known that the surface texture of implanted medical devices affects cell response. Control of cell response has the potential to enhance fixation of implants into bone and, in other applications, to prevent undesired cell adhesion. The potential use of a 100W Q-switched YAG laser miller (DMG Lasertec 60 HSC) for texturing titanium is investigated. A series of regular features with dimensions of the order of tens of micrometers are generated in the surface of titanium samples and the cell response to these features is determined. Characterisation of the laser milled features reveals features with a lengthscale of a few microns superposed on the larger scale structures, this is attributed to resolidification of molten droplets generated and propelled over the surface by individual laser pulses. The laser textured samples are exposed to osteoblast cells and it is seen that cells do respond to the features in the laser textured surfaces.

  7. Compact, passively Q-switched Nd:YAG laser for the MESSENGER mission to Mercury.

    Science.gov (United States)

    Krebs, Danny J; Novo-Gradac, Anne-Marie; Li, Steven X; Lindauer, Steven J; Afzal, Robert S; Yu, Anthony W

    2005-03-20

    A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter, an instrument on the Mercury Surface, Space Environment, Geochemistry, and Ranging mission to the planet Mercury. The laser achieves 5.4% efficiency with a near-diffraction-limited beam. It passed all space-flight environmental tests at subsystem, instrument, and satellite integration testing and successfully completes a postlaunch aliveness check en route to Mercury. The laser design draws on a heritage of previous laser altimetry missions, specifically the Ice Cloud and Elevation Satellite and the Mars Global Surveyor, but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury.

  8. A highly efficient graphene oxide absorber for Q-switched Nd:GdVO4 lasers

    International Nuclear Information System (INIS)

    Wang Yonggang; Wen Xiaoming; Tang Jau; Chen, Hou Ren; Hsieh, Wen Feng

    2011-01-01

    We demonstrated that graphene oxide material could be used as a highly efficient saturable absorber for the Q-switched Nd:GdVO 4 laser. A novel and low-cost graphene oxide (GO) absorber was fabricated by a vertical evaporation technique and high viscosity of polyvinyl alcohol (PVA) aqueous solution. A piece of GO/PVA absorber, a piece of round quartz, and an output coupler mirror were combined to be a sandwich structure passive component. Using such a structure, 104 ns pulses and 1.22 W average output power were obtained with the maximum pulse energy at 2 µJ and a slope efficiency of 17%.

  9. Precise alignment of a longitudinal Pockels Cell for Q-switch operation Nd:YAG laser

    International Nuclear Information System (INIS)

    Nisperuza, D.; Botero, G.; Bastidas, A.

    2009-01-01

    The failure to accurately center optical components may, especially in the case of high gain of the Nd:YAG lasers, produce strong parasitic off-axis laser action capable of causing severe component damage typically to the Pockels cell. We report a precise longitudinal alignment of the Pockels cell by modulating the laser polarization using an experimental setup of circular dichroism. This procedure is based on the use of an analyzer at 0 o or 45 o of the Pockels cell axes, and it allows us to adjust the Q-switching delay for best pulse shape, maximum output energy and to reduce the lack of symmetry of the spot laser considerably. (Author)

  10. Pure antimony film as saturable absorber for Q-switched erbium-doped fiber laser

    Science.gov (United States)

    Rahman, M. F. A.; Zhalilah, M. Z.; Latiff, A. A.; Rosol, A. H. A.; Lokman, M. Q.; Bushroa, A. R.; Dimyati, K.; Harun, S. W.

    2018-04-01

    This paper reports on the use of Antimony (Sb) polymer film to generate stable Q-switching pulses in Erbium-doped fiber laser (EDFL) cavity. The SA is fabricated by coating a thin layer of Sb on a polyvinyl alcohol (PVA) film through physical vapour deposition (PVD) process. A 1 × 1 mm area of the film SA is cut and integrated into between two fiber ferrules inside the laser cavity for intra-cavity loss modulation. Self-starting and stable Q-switched pulses are obtained within a pump power range from 60 to 142 mW. Within this range, the repetition rate increases from 70.82 to 98.04 kHz, while pulse width decreases from 7.42 to 5.36 μs. The fundamental frequency signal-to-noise ratio of the pulse signal is 74 dB, which indicates the excellent stability of the pulses. The maximum output power and pulse energy are 8.45 mW and 86.19 nJ, respectively. Our demonstration shows that Sb film SA capable of generating stable pulses train operating at 1.55-micron region.

  11. Experimental and Numerical Comparison Q-Switched Fiber Laser Generation using Graphene as Saturable Absorber

    Directory of Open Access Journals (Sweden)

    Awang Noor Azura

    2018-01-01

    Full Text Available We demonstrated the comparison experimentally and numerically a compact Q-switched erbium-doped fiber (EDF laser based on graphene as a saturable absorber (SA. By optically driven deposition of graphene on a fiber core, the SA is constructed and inserted into a diode-pumped EDF laser cavity. Lasing in CW region starts at 10 mW, whereas stable self-starting Q-switching with a central wavelength of 1530 nm begins at 18 mW. In this paper, at 35 mW, the maximum pulse energy reaches at 2 μJ with pulse repetition rate of 1 MHz and the narrowest pulse width is around 10 μs is obtained. The stability of the pulse is verified from the radio-frequency (RF spectrum with a measured signal-to-noise ratio (SNR of 48 dB. In this study, the design is compared with the simulation using the Optisystem software. The output power of the experimental study is also compared with the simulation to examine the performance.

  12. Q-switched ruby laser irradiation of normal human skin. Histologic and ultrastructural findings.

    Science.gov (United States)

    Hruza, G J; Dover, J S; Flotte, T J; Goetschkes, M; Watanabe, S; Anderson, R R

    1991-12-01

    The Q-switched ruby laser is used for treatment of tatoos. The effects of Q-switched ruby laser pulses on sun-exposed and sun-protected human skin, as well as senile lentigines, were investigated with clinical observation, light microscopy, and transmission electron microscopy. A pinpricklike sensation occurred at radiant exposures as low as 0.2 J/cm2. Immediate erythema, delayed edema, and immediate whitening occurred with increasing radiant exposure. The threshold for immediate whitening varied inversely with skin pigmentation, ranging from a mean of 1.4 J/cm2 in lentigines to 3.1 J/cm2 in sun-protected skin. Transmission electron microscopy showed immediate alteration of mature melanosomes and nuclei within keratinocytes and melanocytes, but stage I and II melanosomes were unaffected. Histologically, immediate injury was confined to the epidermis. There was minimal inflammatory response 1 day after exposure. After 1 week, subthreshold exposures induced hyperpigmentation, with epidermal hyperplasia and increased melanin staining noted histologically. At higher radiant exposures, hypopigmentation occurred with desquamation of a pigmented scale/crust. All sites returned to normal skin color and texture without scarring within 3 to 6 months. These observations suggest that the human skin response to selective photothermolysis of pigmented cells is similar to that reported in animal models, including low radiant exposure stimulation of melanogenesis and high radiant exposure lethal injury to pigmented epidermal cells.

  13. Dynamics of a self-Q-switched fiber laser with a Rayleigh-stimulated Brillouin scattering ring mirror

    Science.gov (United States)

    Fotiadi, Andrei A.; Mégret, Patrice; Blondel, Michel

    2004-05-01

    Backward light scattering can cause passive Q switching in fiber lasers. We propose a self-consistent description of the laser dynamics. Our model quantitatively reproduces the temporal structure of pulsation and is also attractive for analysis of laser stability and statistics. The validity of the model is directly verified in an experiment.

  14. Pulsed Q-switched ruby laser annealing of Bi implanted Si crystals investigated by channeling

    International Nuclear Information System (INIS)

    Deutch, B.I.; Shih-Chang, T.; Shang-Hwai, L.; Zu-Yao, Z.; Jia-Zeng, H.; Ren-Zhi, D.; Te-Chang, C.; De-Xin, C.

    1979-01-01

    Channeling was used to investigate pulsed, Q switched ruby-laser annealed and thermally annealed Si single crystals implanted with 40-keV Bi ions to a dose of 10 15 atoms/cm 2 . After thermal annealing, residual damage decreased with increasing annealing temperature to a minimum value of 30% at 900 0 C. The Bi atoms in substitutional sites reached a maximum value (50%) after annealing at 750 0 C but decreased with increasing annealing temperature. Out diffusion of Bi atoms occurred at temperatures higher than 625 0 C. For comparison, the residual damage disappeared almost completely after pulsed-laser annealing (30 ns pulse width, Energy, E = 3J/cm 2 ). The concentration of Bi in Si exceeded its solid solubility by an order of magnitude; 95% of Bi atoms were annealed to substitutional sites. Laser pulses of different energies were used to investigate the efficiency of annealing. (author)

  15. Diode pumped actively Q-switched Nd:YVO4 self-Raman laser

    International Nuclear Information System (INIS)

    Su Fufang; Zhang Xingyu; Wang Qingpu; Ding Shuanghong; Jia Peng; Li Shutao; Fan Shuzhen; Zhang Chen; Liu Bo

    2006-01-01

    By using Nd:YVO 4 as the gain medium and the Raman medium simultaneously, the actively Q-switched operation of the self-Raman Nd:YVO 4 laser at 1176 nm was realized. The output characteristics including the average power, pulse energy and pulse width versus the incident pump power and pulse repetition rate were investigated. At a pulse repetition rate of 20 kHz an average power up to 0.57 W was obtained with the incident pump power of 10.2 W, corresponding to a conversion efficiency of 5.6% with respect to the diode laser input power. Meanwhile, an analysis of the self-Raman Nd:YVO 4 laser was carried out by using the rate equations. The obtained theoretical results were in agreement with the experimental results on the whole

  16. Q-switched laser removal of tattoos: a clinical and spectroscopic investigation of the mechanism

    Science.gov (United States)

    Siomos, Konstadinos; Bailey, Raymond T.; Cruickshank, Frank R.; Murphy, Michael

    1996-01-01

    The liquid phase spectra of tatoo pigments are shown to be unreliable as a basis for mechanistic deductions. The reflectance spectra of the solids from 2000 nm to 500 nm (5000 to 20,000 cm-1) are shown to accurately assess the relative loss of laser light for different pigments and to be useful in examining these to check for similarities in the pigments. The absorbance differences between the pigments are shown to be largely irrelevant in assessing the ease of tatoo removal by laser radiation of a variety of wavelengths. A multiphoton absorption mechanism with its concomitant shock wave is proposed to be responsible for the reduction of pigment particles to small sizes which the lymph system can remove. The different behavior of blue and green tattoos, treated by Q-switched ruby and Nd:YAG lasers, is attributed to the particle aggregation size of the pigments in the tattoo.

  17. Tattoo removal by Q-switched yttrium aluminium garnet laser: client satisfaction.

    Science.gov (United States)

    Hutton Carlsen, K; Esmann, J; Serup, J

    2017-05-01

    Tattoo removal by Q-switched yttrium aluminium garnet (YAG) lasers is golden standard; however, clients' satisfaction with treatment is little known. To determine clients' satisfaction with tattoo removal. One hundred and fifty-four tattoo removal clients who had attended the private clinic 'Centre for Laser Surgery', Hellerup, Denmark, from 2001 to 2013 completed a questionnaire concerning outcome expectations, level of pain experiences and satisfaction with tattoo removal. The laser surgeon and his team were blinded from data handling. The study design included a minimum 2-year postlaser treatment observation period from 2013 to 2015. Overall, clients were satisfied with their laser treatment; 85% assessed their treatment and results to be acceptable to superb, while 15% assessed their treatment and results to be inferior to unacceptable. Effectiveness relative to colour of tattoo on a scale from 0 (no effect) to 10 (complete removal) scored a mean of blue 9.5, black 9.4, yellow 8.9, red 8.8 and green 6.5. Clients were dissatisfied with green pigment remnants, which could mimic bruising. One hundred and twenty-nine clients (84%) experienced moderate to extreme pain during treatment. Twenty-eight (20%) developed minor scarring. There were many reasons for tattoo removal; e.g. stigmatisation (33%), conspicuousness (29%) and poor artistic quality (22%). One hundred and two clients had expected complete removal of tattoos without a blemish, expectations that were only partly fulfilled. During the treatment period, clients adjusted expectations and adapted more realistic views of outcomes. The majority of clients were satisfied with Q-switched YAG laser removal of tattoos despite high pretreatment expectations which were only partly met. The study supports YAG lasers for tattoo removal as acceptable therapy of today, with room for new approaches. © 2017 European Academy of Dermatology and Venereology.

  18. Laser annealing of ion implanted silicon by the aid of a Q-switched neodymium glass laser

    International Nuclear Information System (INIS)

    Exner, H.; Laemmel, B.; Zscherpe, G.

    1984-01-01

    Experimental results of laser annealing of arsenic implanted silicon are presented. Different depths of melting are obtained by varying the energy flux density of the Q-switched neodymium glass laser. The annealed samples are studied by the aid of optical microscopy, scanning electron microscopy, Rutherford backscattering spectrometry (RBS) combined with ion channeling, and of resistance measurements. Not any defect could be found by RBS and no surface structure could be determined by microscopy

  19. Simulation of medical Q-switch flash-pumped Er:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yanlin; Huang Chuyun; Yao Yucheng; Zou Xiaolin, E-mail: Wangyanlin0@126.com, E-mail: chuyunh@163.com, E-mail: yyuch@soho.com, E-mail: zouxiaol@126.com [Physics school, Hubei University of Technology, Wuhan, China 430068 (China)

    2011-01-01

    Er: YAG laser, the wavelength is 2940nm, can be absorbed strongly by water. The absorption coefficient is as high as 13000 cm{sup -1}. As the water strong absorption, Erbium laser can bring shallow penetration depth and smaller surrounding tissue injury in most soft tissue and hard tissue. At the same time, the interaction between 2940nm radiation and biological tissue saturated with water is equivalent to instantaneous heating within limited volume, thus resulting in the phenomenon of micro-explosion to removal organization. Different parameters can be set up to cut enamel, dentin, caries and soft tissue. For the development and optimization of laser system, it is a practical choice to use laser modeling to predict the influence of various parameters for laser performance. Aim at the status of low Erbium laser output power, flash-pumped Er: YAG laser performance was simulated to obtain optical output in theory. the rate equation model was obtained and used to predict the change of population densities in various manifolds and use the technology of Q-switch the simulate laser output for different design parameters and results showed that Er: YAG laser output energy can achieve the maximum average output power of 9.8W under the given parameters. The model can be used to find the potential laser systems that meet application requirements.

  20. Actively Q-switched laser with novel Nd:YAG/YAG polygonal active-mirror

    Science.gov (United States)

    Lang, Ye; Chen, Yanzhong; Ge, Wenqi; He, Jianguo; Zhang, Hongbo; Liao, Lifen; Xin, Jianguo; Zhang, Jian; Fan, Zhongwei

    2018-03-01

    In this work, we demonstrate an efficient actively Q-switched laser based on a novel crystal Nd:YAG/YAG polygonal active mirror. A passively cooled crystal Nd:YAG/YAG polygonal active mirror with an end pump scheme was used as the gain medium. For the overlap between the TEM00 laser mode and large gain profile, a cavity was carefully designed with a large fundamental mode volume. With a maximum absorbed power of 3.1 W, a 685 mW average output power with a pulse repetition of 5 kHz was attained, and the corresponding optical-optical and slope efficiency were 22.1% and 27.7%, respectively. The pulse width was 133.9 ns. The beam quality (M 2) was 1.561 in the horizontal direction and 1.261 in the vertical direction.

  1. High Power Q-Switched Dual-End-Pumped Ho:YAG Laser

    Energy Technology Data Exchange (ETDEWEB)

    Xiao-Ming, Duan; Ying-Jie, Shen; Tong-Yu, Dai; Bao-Quan, Yao; Wang Yue-Zhu, E-mail: xmduan@hit.edu.cn [National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2012-09-15

    We report the high power acousto-optically Q-switched operation of a dual-end-pumped Ho:YAG laser at room temperature. For the Q-swithched mode, a maximum pulse energy of 2.4 mJ and a minimum pulse width of 23 ns at the repetition rate of 10 kHz are achieved, resulting in a peak power of 104.3 kW. The beam quality factor of M{sup 2} {approx} 1.5, which is demonstrated by a knife-edge method. In addition, the Ho:YAG laser is employed as a pumping source of ZGP optical parametric oscillator, and its total average output power is 13.2 W at 3.9 {mu}m and 4.4 {mu}m with a slope efficiency of 68.4%.

  2. Structure of picosecond pulses of a Q-switched and mode-locked diode-pumped Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Donin, V I; Yakovin, D V; Gribanov, A V [Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2015-12-31

    The pulse duration of a diode-pumped Nd:YAG laser, in which Q-switching with mode-locking (QML regime) is achieved using a spherical mirror and a travelling-wave acousto-optic modulator, is directly measured with a streak camera. It is found that the picosecond pulses can have a non-single-pulse structure, which is explained by excitation of several competing transverse modes in the Q-switching regime with a pulse repetition rate of 1 kHz. In the case of cw mode-locking (without Q-switching), a new (auto-QML) regime is observed, in which the pulse train repetition rate is determined by the frequency of the relaxation oscillations of the laser field while the train contains single picosecond pulses. (control of laser radiation parameters)

  3. Q-switching and mode-locking in a diode-pumped frequency-doubled Nd : YAG laser

    International Nuclear Information System (INIS)

    Donin, Valerii I; Yakovin, Dmitrii V; Gribanov, A V

    2012-01-01

    A new method for obtaining Q-switching simultaneously with mode-locking using one travelling-wave acousto-optic modulator in a frequency-doubled Nd : YAG laser cavity is described. Further shortening of output laser pulses (from 40 to 3.25 ps) is achieved by forming a Kerr lens in the frequency-doubling crystal. At an average power of ∼ 2 W and a Q-switching rate of 2 kHz, the peak power of the stably operating reached ∼ 50 MW.

  4. Nanosecond Tm:Y2O3 ceramic laser passively Q-switched by a Ho:LuAG ceramic

    Science.gov (United States)

    Wang, Hui; Huang, Haitao; Wang, Shiqiang; Shen, Deyuan

    2018-02-01

    A passively Q-switched 2.05-μm Tm:Y2O3 ceramic laser, employing Ho:LuAG ceramic as a saturable absorber, was demonstrated for the first time. Under the absorbed pump power of 20.5 W, a maximum output power of 497 mW was obtained. Pulses with a minimum pulse width of 642 ns under the repetition rate of 33 kHz were achieved. Our works validate that Ho-doped materials have good potential for passive Q-switching of Tm-doped lasers at 2-μm wavelength region.

  5. Comprehensive study of electro-optic and passive Q-switching in solid state lasers for altimeter applications

    Science.gov (United States)

    Bhardwaj, Atul; Agrawal, Lalita; Pal, Suranjan; Kumar, Anil

    2006-12-01

    Laser Science and Technology Center (LASTEC), Delhi, is developing a space qualified diode pumped Nd: YAG laser transmitter capable of generating 10 ns pulses of 30 mJ energy @ 10 pps. This paper presents the results of experiments for comparative studies between electro-optic and passively Q-switched Nd: YAG laser in a crossed porro prism based laser resonator. Experimental studies have been performed by developing an economical bench model of flash lamp pumped Nd: YAG laser (rod dimension, \

  6. An Nd:YLF laser Q-switched by a monolayer-graphene saturable-absorber mirror

    International Nuclear Information System (INIS)

    Matía-Hernando, Paloma; Guerra, José Manuel; Weigand, Rosa

    2013-01-01

    We demonstrate Q-switched operation of a transversely diode-pumped Nd:YLF (yttrium lithium fluoride) laser using chemical vapour deposition-grown large-area monolayer graphene transferred to a dielectric saturable-absorber mirror (G-SAM). The resulting compact design operates at 1047 nm with 2.5 μs pulses in a 100% modulation Q-switch regime with an average and very stable output power of 0.5 W. Different cavity lengths have been employed and the results are compared against a theoretical model based on rate equations, evidencing the role of transverse pumping in the system. The model also reveals that monolayer graphene effectively leads to shorter and more powerful pulses compared to those with multilayer graphene. These results establish the potential of single-layer graphene for providing a reliable and efficient Q-switch mechanism in solid-state lasers. (paper)

  7. Q-Switched Operation with Carbon-Based Saturable Absorbers in a Nd:YLF Laser

    Directory of Open Access Journals (Sweden)

    Rosa Weigand

    2015-09-01

    Full Text Available We have numerically studied the influence of the absorption modulation depth of carbon-based saturable absorbers (graphene and carbon nanotubes (CNTs on the Q-switched regime of a diode-pumped Nd:YLF laser. A short-length cavity was used with an end mirror on which CNTs or mono- or bi-layer graphene were deposited, forming a saturable absorber mirror (SAM. Using a standard model, the generated energy per pulse was calculated, as well as the pulse duration and repetition rate. The results show that absorbers with higher modulation depths, i.e., graphene, deliver higher energy pulses at lower repetition rates. However, the pulse duration did not have a monotonic behavior and reaches a minimum for a given low value of the modulation depth typical of CNTs.

  8. Q-Switched Nd:YAG Laser Removal of Facial Amateur Tattoos in Patients With Fitzpatrick Type VI: Case Series.

    Science.gov (United States)

    Haik, Josef; Kornhaber, Rachel; Harats, Moti; Israeli, Hadar; Orenstein, Arie

    2016-11-01

    Q-switched neodymium:YAG (Nd:YAG) lasers are reported to be gold standard for laser tattoo removal. In particular, the Q-switched Nd:YAG laser at 1064 nm is widely recognized for the removal of blue/black amateur tattoos. However, treatment modalities in Fitzpatrick Type VI skin carry a greater risk of complications including alterations in pigmentation compared to fairer skin (Fitzpatrick Type I-IV skin). Therefore, the aim of this case series was to describe with the use of the Q-Switched Nd:YAG laser, the removal of carbon-based amateur tattoos on patients with Fitzpatrick Type VI skin as an effective and safe method. Twenty- five patients with Fitzpatrick type VI skin, from Ethiopian origins, with facial tribal tattoos, were treated with the Q- Switched Nd:YAG laser at 1064 nm. Digital images were taken upon every treatment and the clearance rates of the tattoo was evalu- ated by imaging software. We observed an average tattoo clearance rate of 95% among the 45 facial tattoos in 25 patients presented in the case series with minimal pigmentary and textual changes evident. These positive aesthetic results have a signi cant psychosocial impact on the lives of those with Fitzpatrick Type VI skin, in particular the Ethiopian Jewish population. J Drugs Dermatol. 2016;15(11):1448-1452..

  9. 183-W, M2 = 2.4 Yb:YAG Q -switched laser

    International Nuclear Information System (INIS)

    Honea, E.C.; Beach, R.J.; Mitchell, S.C.; Avizonis, P.V.

    1999-01-01

    We have fabricated a diode-array end-pumped Yb:YAG rod laser with output powers greater than 200thinspthinspW cw and 195thinspthinspW Q -switched at 5thinspthinspkHz. At an output power of 183thinspthinspW and a repetition rate of 5thinspthinspkHz, the beam quality was measured to be M 2 =2.4 . The laser design incorporates a hollow lens duct to concentrate the diode pump light for delivery to the end of the laser rod while maintaining access to the laser beam. This configuration provides increased flexibility for the resonator design and permits the use of birefringence compensation in the cavity to yield polarized output with increased efficiency. Using the recently described birefringence compensation method of Clarkson et al.thinspthinsp[in Conference on Lasers and Electro-Optics (Optical Society of America, Washington, D.C., 1998), paper CTuI3], we obtained 112thinspthinspW of cw power with a polarized beam of M 2 =3.2 . copyright 1999 Optical Society of America

  10. Water content contribution in calculus phantom ablation during Q-switched Tm:YAG laser lithotripsy.

    Science.gov (United States)

    Zhang, Jian J; Rajabhandharaks, Danop; Xuan, Jason Rongwei; Wang, Hui; Chia, Ray W J; Hasenberg, Tom; Kang, Hyun Wook

    2015-01-01

    Q-switched (QS) Tm:YAG laser ablation mechanisms on urinary calculi are still unclear to researchers. Here, dependence of water content in calculus phantom on calculus ablation performance was investigated. White gypsum cement was used as a calculus phantom model. The calculus phantoms were ablated by a total 3-J laser pulse exposure (20 mJ, 100 Hz, 1.5 s) and contact mode with N=15 sample size. Ablation volume was obtained on average 0.079, 0.122, and 0.391  mm3 in dry calculus in air, wet calculus in air, and wet calculus in-water groups, respectively. There were three proposed ablation mechanisms that could explain the effect of water content in calculus phantom on calculus ablation performance, including shock wave due to laser pulse injection and bubble collapse, spallation, and microexplosion. Increased absorption coefficient of wet calculus can cause stronger spallation process compared with that caused by dry calculus; as a result, higher calculus ablation was observed in both wet calculus in air and wet calculus in water. The test result also indicates that the shock waves generated by short laser pulse under the in-water condition have great impact on the ablation volume by Tm:YAG QS laser.

  11. High-power continuous wave and passively Q-switched laser operations of a Nd:GGG crystal

    International Nuclear Information System (INIS)

    Qin, L J; Tang, D Y; Xie, G Q; Dong, C M; Jia, Z T; Tao, X T

    2008-01-01

    We report on the continuous wave (CW) and passive Q-switching performance of a high-power diode-pumped Nd:GGG laser. A CW output power of 7.20 W was obtained under an absorbed pump power of 14.97 W, which gives a slop efficiency of 52.7%. With a Cr 4+ doped yttrium aluminum garnet crystal as the saturable absorber, the shortest passively Q-switched pulse width, largest pulse energy, and highest peak power achieved were 7.7 ns, 126.25 μJ, and 15.5 kW, respectively

  12. High power diode-pumped continuous wave and Q-switch operation of Tm,Ho:YVO4 laser

    International Nuclear Information System (INIS)

    Yao, B Q; Li, G; Meng, P B; Zhu, G L; Ju, Y L; Wang, Y Z

    2010-01-01

    High power diode-pumped continuous wave (CW) and Q-switch operation of Tm,Ho:YVO 4 laser is reported. Using two Tm,Ho:YVO 4 rods in a single cavity, up to 20.2 W of CW output lasing at 2054.7 nm was obtained under cryogenic temperature of 77 K with an optical to optical conversion efficiency of 32.9%. For Q-switch operation, up to 19.4 W of output was obtained under 15 kHz pulse repetition frequency (PRF) with a minimum pulse width of 24.2 ns. In addition, different pulse repetition frequencies of Q-switch operation with 10.0 kHz, 12.5 kHz and 15.0 kHz were investigated comparatively

  13. Passive Q-switching in CW-CO2 laser with SF6 as an intracavity saturable absorber

    International Nuclear Information System (INIS)

    Al-Hawat, Sh.

    2007-10-01

    A passive Q-switching was applied to a tunable CW CO 2 laser with output power about 3.5 W using SF 6 as a saturable absorber inside the cavity. The Q-Switching phenomenon was studied ( pulse shape, pulse duration, repetition rate and conditions of its generation ) at the spectral lines of 10P(10), 10P(26), 10P(28) and 10P(30) from the branch of 10P of CO 2 laser. These lines had a weak absorption in relation to other lines of this branch, under SF 6 pressure till 0.5 mbar. To control the behaviour of such phenomenon, the gases He and Xe were added separately to SF 6 . It was observed that the Q-switching phenomenon was depended on the added gas pressure of Xe and He, through the repetitive rate of pulses , duration and energy of generated laser pulse. A computational program was written to calculate the Q-switching pulses parameters under similar conditions as those applied in the case of SF 6 +He mixture. A comparison was made with the experimental data , not so big discrepancies were observed between them. In addition to that, absorption coefficients of SF 6 were determined in two cases: the first one when the absorption cell was located outside the laser cavity, and the second one when the cell was located inside the cavity. On the basis of obtained coefficients the absorption cross sections of SF 6 were found and compared with NIST database.(author)

  14. Treatment of pigmented keratosis pilaris in Asian patients with a novel Q-switched Nd:YAG laser.

    Science.gov (United States)

    Kim, Sangeun

    2011-06-01

    Treatment for most cases of keratosis pilaris requires simple reassurance and general skin care recommendations. Many Asian patients find lesions due to pigmented keratosis pilaris to be cosmetically unappealing. Treatment of post-inflammatory hyperpigmentation using a 1064-nm Q-switched Nd:YAG laser with low fluence is reported. To investigate the efficacy of a novel Q-switched Nd:YAG laser for the treatment of pigmented keratosis pilaris in Asian patients. Ten patients with pigmented keratosis pilaris underwent five weekly treatments using a Q-switched Nd:YAG laser (RevLite(®); HOYA ConBio(®), Freemont, CA, USA) at 1064 nm with a 6-mm spot size and a fluence of 5.9 J/cm(2). Photographic documentation was obtained at baseline and 2 months after the final treatment. Clinical improvement was achieved in all 10 patients with minimal adverse effects. For the treatment of keratosis pilaris, the use of a Q-switched Nd:YAG laser can be helpful for improving cosmetic appearance as it can improve pigmentation.

  15. SBS pulse compression applied to a commercial Q-switch Nd-YAG laser

    International Nuclear Information System (INIS)

    Aliaga-Rossel, R.; Bayley, J.; Mamin, A.; Nizienko, Y.

    1997-01-01

    In optical diagnosis of dense Z-pinches, sub-nanosecond laser pulses are required in order to freeze the movement of the plasma during the probing. Commercial lasers can provide such type of pulses but they are either very expensive, or they have a very low energy per pulse. A technique that uses Stimulated Brillouin Scattering (SBS) to compress a 8 ns pulse of a commercial Q-switched Nd-YAG laser is reported here. To carry out this passive compression technique, a frequency doubled laser pulse of 10 ns was focused into a single SBS gas cell, 2 m long, filled with a mixture of argon and sulphurhexafluoride (SF 6 ) at a total pressure of 40 bar. A shorter and high intensity pulse was reflected from the cell (created by SBS) and it travelled back along its original path until it was separated from its original direction by using a dichroic polariser. The pumping volume of the SBS cell, the convergence of the incident beam and the pressure of the gas cell, were optimised to maximise both temporal compression and the output energy. Pulses of 10 ns were compressed to less than 400 ps with a conversion efficiency of 80%. This SBS pulse compression system has been used to make most of the optical measurements of a dense fibre pinch plasma produced in the MAGPIE generator

  16. Multi-operational tuneable Q-switched mode-locking Er fibre laser

    Science.gov (United States)

    Qamar, F. Z.

    2018-01-01

    A wavelength-spacing tuneable, Q-switched mode-locking (QML) erbium-doped fibre laser based on non-linear polarization rotation controlled by four waveplates and a cube polarizer is proposed. A mode-locked pulse train using two quarter-wave plates and a half-wave plate (HWP) is obtained first, and then an extra HWP is inserted into the cavity to produce different operation regimes. The evolutions of temporal and spectral dynamics with different orientation angles of the extra HWP are investigated. A fully modulated stable QML pulse train is observed experimentally. This is, to the author’s best knowledge, the first experimental work reporting QML operation without adding an extra saturable absorber inside the laser cavity. Multi-wavelength pulse laser operation, multi-pulse train continuous-wave mode-locking operation and pulse-splitting operations are also reported at certain HWP angles. The observed operational dynamics are interpreted as a mutual interaction of dispersion, non-linear effect and insertion loss. This work provides a new mechanism for fabricating cheap tuneable multi-wavelength lasers with QML pulses.

  17. Laboratory model for the study and treatment of traumatic tattoos with the Q-switched ruby laser

    Science.gov (United States)

    Silverman, Richard T.; Lach, Elliot

    1994-09-01

    The outcome of laser tattoo removal is dependent on the type of laser and characteristics of the tattoo. A rabbit model was developed to study the Q-switched ruby laser in the treatment of traumatic tattooing. On the backs of white New Zealand rabbits, three 3 cm patches were dermabraded and dressed with carbon black and antibiotic ointment. After a healing period of eight weeks, pre-treatment biopsies were obtained, and the rabbits were treated with the Q- switched ruby laser at various fluence settings with a pulse width of 34 nsec. At set intervals, further biopsies were obtained and studied with light and electron microscopic analysis, and photodocumentation was performed. Grossly, clearance of the tattooed areas was noted in the laser treated specimens. More effective clearance was observed with higher fluence treatment. No infections occurred, and hair regrowth was noted in all cases, though the rate seemed to be altered by laser treatment.

  18. Optimized fiber delivery system for Q-switched, Nd:YAG lasers

    International Nuclear Information System (INIS)

    Setchell, R.E.

    1997-01-01

    Interest in the transmission of high intensities through optical fibers is being motivated by an increasing number of applications. Using different laser types and fiber materials, various studies are encountering transmission limitations due to laser-induced damage processes. For a number of years we have been investigating these limiting processes during the transmission of Q-switched, multimode, Nd:YAG laser pulses through step-index, multimode, fused-silica fiber. We have found that fiber transmission is often limited by a plasma-forming breakdown occurring at the fiber entrance face. This breakdown can result in subtle surface modifications that leave the entrance face more resistant to further breakdown or damage events. Catastrophic fiber damage can also occur as a result of a variety of mechanisms, with damage appearing at fiber entrance and exit faces, within the initial entry segment of the fiber path, and at other internal sites due to fiber fixturing and routing effects. System attributes that will affect breakdown and damage thresholds include laser characteristics, the design and alignment of laser-to-fiber injection optics, and fiber end-face preparation. In the present work we have combined insights gained in past studies in order to establish what thresholds can be achieved if all system attributes can be optimized to some degree. Our multimode laser utilized past modifications that produced a relatively smooth, quasi-Gaussian profile. The laser-to-fiber injection system achieved a relatively low value for the ratio of peak-to-average fluences at the fiber entrance face, incorporated a mode scrambler to generate a broad mode power distribution within the initial segment of the fiber path, and had improved fixturing to insure that the fiber axis was collinear with the incident laser beam. Test fibers were from a particular production lot for which initial-strength characteristics were established and a high-stress proof test was performed

  19. NUMERICAL SIMULATION OF Q-SWITCHED Nd: YAG LASER WITH UNSTABLE RESONATOR AND OUTPUT VARIABLE REFLECTIVITY MIRROR

    Directory of Open Access Journals (Sweden)

    I. N. Dubinkin

    2017-05-01

    Full Text Available The article deals with a method of numerical simulation of laser oscillation in the radially symmetric unstable resonator with an output variable reflectivity mirror (VRM. Research results of the VRM parameters influence on the spatial and energy properties of the laser radiation are obtained. Numerical simulation of laser oscillation in active and passive Q-switching and comparative analysis of the spatial and energy radiation characteristics is done for these modes.

  20. Theoretical and experimental study of a laser-diode-pumped actively Q-switched Yb:NaY(WO4)2 laser with acoustic-optic modulator

    Science.gov (United States)

    Zhang, Haikun; Xia, Wei; Song, Peng; Wang, Jing; Li, Xin

    2018-03-01

    A laser-diode-pumped actively Q-switched Yb:NaY(WO4)2 laser operating at around 1040 nm is presented for the first time with acoustic-optic modulator. The dependence of pulse width on incident pump power for different pulse repetition rates is measured. By considering the Guassian spatial distribution of the intracavity photon density and the initial population-inversion density as well as the longitudinal distribution of the photon density along the cavity axis and the turn off time of the acoustic-optic Q-switch, the coupled equations of the actively Q-switched Yb:NaY(WO4)2 laser are given. The coupled rate equations are used to simulate the Q-switched process of laser, and the numerical solutions agree with the experimental results.

  1. Continuous-wave and passively Q-switched Nd:YVO4 laser at 1085 nm

    Science.gov (United States)

    Lin, Hongyi; Liu, Hong; Huang, Xiaohua; Zhang, Jiyan

    2017-11-01

    An admirable and efficient Nd:YVO4 laser at 1085 nm is demonstrated with a compact 35 mm plano-plano cavity. A chosen narrow bandpass filter with high-transmittance (HT) coating at 1064 nm (T=96%) and optimized part-reflection (PR) coating at 1085 nm (T=15%) is used as the output coupler. In the continuous-wave (CW) regime, the maximum output power reaches 3110 mW at the pump power of 11.41 W. Based on a Cr:YAG crystal with initial-transmittance of 91%, the first passively Q-switched Nd:YVO4 laser at 1085 nm is achieved. When the pump power is changed from the threshold of 4.50 to 6.08 W, the dual-wavelength lines at 1064 and 1085 nm are generated simultaneously. However, at the pump power of above 6.08 W, the single-wavelength line at 1085 nm is achieved. The largest output power, the highest peak power, and the narrowest pulse width are 1615 mW, 878 W and 26.2 ns, respectively.

  2. Light and electron microscopic analysis of tattoos treated by Q-switched ruby laser

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, C.R.; Anderson, R.R.; Gange, R.W.; Michaud, N.A.; Flotte, T.J. (Massachusetts General Hospital, Boston (USA))

    1991-07-01

    Short-pulse laser exposures can be used to alter pigmented structures in tissue by selective photothermolysis. Potential mechanisms of human tattoo pigment lightening with Q-switched ruby laser were explored by light and electron microscopy. Significant variation existed between and within tattoos. Electron microscopy of untreated tattoos revealed membrane-bound pigment granules, predominantly within fibroblasts and macrophages, and occasionally in mast cells. These granules contained pigment particles ranging from 2-in diameter. Immediately after exposure, dose-related injury was observed in cells containing pigment. Some pigment particles were smaller and lamellated. At fluences greater than or equal to 3 J/cm2, dermal vacuoles and homogenization of collagen bundles immediately adjacent to extracellular pigment were occasionally observed. A brisk neutrophilic infiltrate was apparent by 24 h. Eleven days later, the pigment was again intracellular. Half of the biopsies at 150 d revealed a mild persistent lymphocytic infiltrate. There was no fibrosis except for one case of clinical scarring. These findings confirm that short-pulse radiation can be used to selectively disrupt cells containing tattoo pigments. The physial alteration of pigment granules, redistribution, and elimination appear to account for clinical lightening of the tattoos.

  3. High-damage-resistant tungsten disulfide saturable absorber mirror for passively Q-switched fiber laser.

    Science.gov (United States)

    Chen, Hao; Chen, YuShan; Yin, Jinde; Zhang, Xuejun; Guo, Tuan; Yan, Peiguang

    2016-07-25

    In this paper, we demonstrate a high-damage-resistant tungsten disulfide saturable absorber mirror (WS2-SAM) fabricated by magnetron sputtering technique. The WS2-SAM has an all-fiber-integrated configuration and high-damage-resistant merit because the WS2 layer is protected by gold film so as to avoid being oxidized and destroyed at high pump power. Employing the WS2-SAM in an Erbium-doped fiber laser (EDFL) with linear cavity, the stable Q-switching operation is achieved at central wavelength of 1560 nm, with the repetition rates ranging from 29.5 kHz to 367.8 kHz and the pulse duration ranging from 1.269 μs to 154.9 ns. For the condition of the maximum pump power of 600 mW, the WS2-SAM still works stably with an output power of 25.2 mW, pulse energy of 68.5 nJ, and signal-noise-ratio of 42 dB. The proposed WS2-SAM configuration provides a promising solution for advanced pulsed fiber lasers with the characteristics of high damage resistance, high output energy, and wide tunable frequency.

  4. A study on the clinical characteristics of treating nevus of Ota by Q-switched Nd:YAG laser.

    Science.gov (United States)

    Yan, Liu; Di, Li; Weihua, Wang; Feng, Liu; Ruilian, Li; Jun, Zhou; Hui, Su; Zhaoxia, Ying; Weihui, Zeng

    2018-01-01

    The purpose of this study was to retrospectively analyze the clinical characteristics of treating nevus of Ota by Q-switched Nd:YAG laser in Laser Cosmetology Center of Department of Dermatology, the Second Hospital, Xi'an Jiaotong University. The data of 1168 patients of nevus of Ota were analyzed retrospectively, which included the correlation among lesion color, treatment sessions, sex, age, lesion types, and effect. The Q-switched (QS) Nd:YAG laser system had a higher number of treatment sessions which were positively associated with a better response to treatment. Other variables, including gender, age, the categorization of the lesion according to Tanino's classification, and the color of the lesion, were not associated with the response to treatment. The treatment of nevus of Ota with QS Nd:YAG laser is safe and effective, with rare complications.

  5. Generation of Q-Switched Mode-Locked Erbium-Doped Fiber Laser Operating in Dark Regime

    International Nuclear Information System (INIS)

    Tiu, Zian Cheak; Zarei, Arman; Ahmad, Harith; Harun, Sulaiman Wadi

    2016-01-01

    We demonstrate a stable Q-switched mode-locked erbium-doped fiber laser (EDFL) operating in dark regime based on the nonlinear polarization rotation technique. The EDFL produces a pulse train where the Q-switching envelope is formed by multiple dark pulses. The repetition rate of the Q-switched envelope can be increased from 0.96 kHz to 3.26 kHz, whereas the pulse width reduces from 211 μs to 86 μs. The highest pulse of 479 nJ is obtained at the pump power of 55 mW. It is also observed that the dark pulses inside the Q-switching envelope consist of two parts: square and trailing dark pulses. The shortest pulse width of the dark square pulse is obtained at 40.5 μs when the pump power is fixed at 145 mW. The repetition rate of trailing dark pulses can be increased from 27.62 kHz to 50 kHz as the pump power increases from 55 mW to 145 mW. (paper)

  6. Acousto-Optic Q-Switched Fiber Laser-Based Intra-Cavity Photoacoustic Spectroscopy for Trace Gas Detection

    Directory of Open Access Journals (Sweden)

    Qinduan Zhang

    2017-12-01

    Full Text Available We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency f0 = 5.3 kHz inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C2H2 to select the laser wavelength. The system achieved a linear response (R2 = 0.9941 in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times.

  7. Acousto-Optic Q-Switched Fiber Laser-Based Intra-Cavity Photoacoustic Spectroscopy for Trace Gas Detection.

    Science.gov (United States)

    Zhang, Qinduan; Chang, Jun; Wang, Qiang; Wang, Zongliang; Wang, Fupeng; Qin, Zengguang

    2017-12-25

    We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency f ₀ = 5.3 kHz) inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C₂H₂) to select the laser wavelength. The system achieved a linear response (R² = 0.9941) in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times.

  8. A Filmy Black-Phosphorus Polyimide Saturable Absorber for Q-Switched Operation in an Erbium-Doped Fiber Laser

    Directory of Open Access Journals (Sweden)

    Tianxian Feng

    2016-11-01

    Full Text Available We demonstrate an erbium-doped fiber laser passively Q-switched by a black-phosphorus polyimide film. The multi-layer black-phosphorus (BP nanosheets were prepared via a liquid exfoliation approach exploiting N-methylpyrrolidone as the dispersion liquid. By mixing the BP nanosheets with polyimide (PI, a piece of BP–PI film was obtained after evaporating the mixture in a petri dish. The BP–PI saturable absorber had a modulation depth of 0.47% and was inserted into an erbium-doped fiber laser to realize passive Q-switched operations. The repetition rate of the Q-switched laser increased from 5.73 kHz to 31.07 kHz when the laser pump was enhanced from 31.78 mW to 231.46 mW. Our results show that PI is an excellent host material to protect BP from oxidation, and the BP–PI film can act as a promising nonlinear optical device for laser applications.

  9. Switchable Q-switched and modelocked operation in ytterbium doped fiber laser under all-normal-dispersion configuration

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, Pranb K., E-mail: pkm@rrcat.gov.in; Gupta, Pradeep K.; Singh, Chandra Pal; Singh, Amarjeet; Sharma, Sunil K.; Bindra, Kushvinder S.; Oak, Shrikant M. [Solid State Laser Division, Raja Ramanna Center for Advanced Technology, Indore, M.P. 452013 (India)

    2015-03-15

    We have constructed an Yb-doped fiber laser in all-normal-dispersion configuration which can be independently operated in Q-switched or modelocked configuration with the help of a simple fiber optic ring resonator (FORR). In the presence of FORR, the laser operates in Q-switched mode producing stable pulses in the range of 1 μs-200 ns with repetition rate in the range of 45 kHz-82 kHz. On the other hand, the laser can be easily switched to mode-locked operation by disjoining the FORR loop producing train of ultrashort pulses of ∼5 ps duration (compressible to ∼150 fs) at ∼38 MHz repetition rate. The transmission characteristics of FORR in combination with the nonlinear polarization rotation for passive Q-switching operation is numerically investigated and experimentally verified. The laser can serve as a versatile seed source for power amplifier which can be easily configured for application in the fields that require different pulsed fiber lasers.

  10. Compact, Passively Q-Switched Nd:YAG Laser for the MESSENGER Mission to the Planet Mercury

    Science.gov (United States)

    Krebs, Danny J.; Novo-Gradac, Anne-Marie; Li, Steven X.; Lindauer, Steven J.; Afzal, Robert S.; Yu, Antony

    2004-01-01

    A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter (MLA) instrument which is an instrument on the MESSENGER mission to the planet Mercury. The laser achieves 5.4 percent efficiency with a near diffraction limited beam. It has passed all space flight environmental tests at system, instrument, and satellite integration. The laser design draws on a heritage of previous laser altimetry missions, specifically ISESAT and Mars Global Surveyor; but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury.

  11. Q-switched Yb3+:YAG laser using plasmonic Cu2-xSe quantum dots as saturable absorbers

    Science.gov (United States)

    Wang, Yimeng; Zhan, Yi; Lee, Sooho; Wang, Li; Zhang, Xinping

    2018-04-01

    Cu2-xSe quantum dots (QDs) were synthesized by organometallic synthesis methods. Due to heavy self-doping, the Cu2-xSe QDs exhibit particle plasmon resonance in the near-infrared. Transient absorption spectroscopic investigation revealed strong nonlinear optical absorption and bleaching performance of the QDs under femtosecond pulse excitation, which enabled the Cu2-xSe QDs to be excellent saturable absorbers and applied in Q-switched or mode-locked lasers. A passively Q-switched Yb3+:YAG solid-state laser at 1.03 μm was achieved by coating Cu2-xSe QDs as saturable absorbers onto one of the output coupler of the V-shaped linear cavity.

  12. Use of Q-switched alexandrite laser (755 nm, 100 nsec) for removal of traumatic tattoo of different origins.

    Science.gov (United States)

    Moreno-Arias, G A; Casals-Andreu, M; Camps-Fresneda, A

    1999-01-01

    Q-switched laser systems have been used for removal of tattoo-related carbon, graphite, and other particles. We assessed elimination of traumatic tattoos of different origin with Q-switched alexandrite laser in nine patients. Fluence threshold was determined and a spot test was made. Q-switched alexandrite laser, with a fluence range 4.5-8.0 J/cm(2) (mean, 7.16 +/- 1.18), was used at 4-5-week intervals. Total treatment ranged from 3-12 sessions (mean, 6.1 +/- 3.6 sessions). Double-pulse technique was used in black/black-bluish areas, but single-shot was applied to slate-gray pigment. More than 95% lightening was achieved in five patients after 5.2 +/- 2.3 sessions, and >75% lightening in six subjects after 6.1 +/- 3.1 sessions of treatment. Blacktop, surgical pen, and gravel tattoos presented a better response than gunpowder/fireworks tattoos (>95% vs. 68.7 +/- 23.9% clearance), or tattoos of unknown origin (>95% vs. 62.5 +/- 53% clearance). Epidermal splattering and pinpoint bleeding were observed in one case. No pigmentary alteration or scarring was seen. The Q-switched alexandrite laser is a useful system for removal of traumatic tattoos of diverse origin. The best response (>95% clearance) was achieved in blacktop, surgical pen, and gravel tattoos, although an acceptable degree of lightening may be obtained in tattoos due to gunpowder or fireworks. Copyright 1999 Wiley-Liss, Inc.

  13. Effects of Q-switched and long-pulsed 1064 nm Nd:YAG laser on enlarged facial pores.

    Science.gov (United States)

    Lee, Chang Nam; Kim, You Jeong; Lee, Hyun Seung; Kim, Hei Sung

    2009-12-01

    'Enlarged facial pore' is a subjective term, which is not clearly defined but often complained by many. A diverse range of treatments are used though evidence of efficacy remains largely anecdotal. We report a series of nine patients who underwent a split face trial with Q-switched 1064 nm Nd:YAG and long-pulsed 1064 nm Nd:YAG laser to treat enlarged facial pores.

  14. Microstructure and mechanical changes induced by Q-Switched pulse laser on human enamel with aim of caries prevention

    Science.gov (United States)

    Apsari, R.; Pratomo, D. A.; Hikmawati, D.; Bidin, N.

    2016-03-01

    This study was conducted to determine the effect of Q-Switched Nd: YAG laser energy dose to human enamel caries. The specifications of Q-Switched Nd: YAG laser as followed: wavelength of 1064 nm and 6 ns pulse width. Caries enamel samples taken from human teeth molars of 17-35 ages and the type of media caries. Energy doses used in this study were 723.65 mJ/cm2, 767.72 mJ/cm2, and 1065.515 mJ/cm2; 5 Hz repetition rate, and 20 second exposure time. Samples characterized the surface morphology and the percentage of constituent elements, especially calcium/phosphorus (Ca/P) with FESEM-EDAX. The fraction volume and crystallinity percentage of hydroxyapatite (HA) with XRD and hardness value using Vickers Microhardness Test. The results indicated that exposure of Q-Switched Nd:YAG laser on enamel caries resulting cracks, holes, and melt due to plasma production effects in the surface. Plasma production effect also resulted in micro properties such as percentage of Ca/P was close to normal, the fraction volume and crystallinity percentage of HA went up but did not change the crystal structure (in terms of the lattice structure). The hardness value also rose as linear as exposure energy dose caused by phototermal effect. Based on the results, Q-Switched Nd:YAG laser can be used as contactless drill dental caries replacement candidate with the additional therapy effect such as localized caries in order to avoid the spread, the ratio of Ca/P approaching healthy teeth, the fraction volume and crystallinity percentage of HA rose and established stronger teeth with peak energy dose 1065.515 mJ/cm2.

  15. Role of Q-switched ND:YAG laser in nevus of Ota: A study of 25 cases

    Directory of Open Access Journals (Sweden)

    Shivangi Sharma

    2011-01-01

    Full Text Available Background: Nevus of Ota is common condition in Indian patients. The condition is more common in females, with a male-female ratio of 1:4.8. Aim : To evaluate long-term efficacy safety and stability of Q-switched ND:YAG laser in treatment of Nevus of Ota. Design: 6 month follow-up of patients of Nevus of Ota, treated with Q-switched ND:YAG laser Materials and Methods : Twenty-five patients of Nevus of Ota were treated with Q-switched ND:YAG laser for a period of 1 year and 9 months; patient had fitzpatricks skin type 4 and 5; detailed history, clinical examination, ophthalmoscopy, and otoscopy was done in all cases; clinical photographs were taken before and after the completion of treatments. Six-month follow-up was done after the last session. Response to treatment was graded based on physician′s global assessment. Result : More than 70% improvement was seen in 15 patients (60%. Eight patients (32% had moderate and two patients (8% showed mild improvement.

  16. Double-Arched LD Array Stagger Pumped Electro-Optic Q-Switched Nd:YAG Laser without Water Cooling

    International Nuclear Information System (INIS)

    Xin-Yu, Chen; Guang-Yong, Jin; Yong-Ji, Yu; Chao, Wang; Da-Wei, Hao; Yi-Bo, Wang

    2010-01-01

    We report an experimental study on a double-arched LD array stagger pumped electro-optic Q-switched Nd:YAG laser without water cooling by using a convex-concave compensate resonator. Perfect matching of the gain field inside the rod and the fundamental mode of the cavity is made by this structure. When the repetition rate is 20 Hz, A maximum output energy at 1064 nm wavelength of 176 mJ (M 2 = 1.55) and 9.6 ns FWHM pulse width in fundamental mode Q-switch operation is obtained with LD injection current 120 A. The optical-optical conversion efficiency is 14.7%, the divergence angle of the output beam is about 1.8 mrad. (fundamental areas of phenomenology(including applications))

  17. Passively Q-switched microchip Er, Yb:YAl3(BO3)4 diode-pumped laser.

    Science.gov (United States)

    Kisel, V E; Gorbachenya, K N; Yasukevich, A S; Ivashko, A M; Kuleshov, N V; Maltsev, V V; Leonyuk, N I

    2012-07-01

    We report, for the first time to our knowledge, a diode-pumped cw and passively Q-switched microchip Er, Yb:YAl(3)(BO(3))(4) laser. A maximal output power of 800 mW at 1602 nm in the cw regime was obtained at an absorbed pump power of 7.7 W. By using Co(2+):MgAl(2)O(4) as a saturable absorber, a TEM(00)-mode Q-switched average output power of 315 mW was demonstrated at 1522 nm, with pulse duration of 5 ns and pulse energy of 5.25 μJ at a repetition rate of 60 kHz.

  18. Radially polarized and passively Q-switched Yb-doped fiber laser based on intracavity birefringent mode discrimination

    Science.gov (United States)

    Sun, Xuehuan; Wu, Yongxiao; Chen, Sanbin; Li, Jianlang

    2018-05-01

    In this paper, we demonstrated a passive Q-switched ytterbium-doped fiber laser with radially polarized beam emission by using a c-cut YVO4 birefringent crystal as the intracavity polarization discriminator, and a Cr4+:YAG crystal as the saturable absorber and output coupler. The maximum averaged laser power reached 3.89 W with a high slope efficiency of 66.5%. The laser pulse had a peak power of 161 W, 160 ns duration, and 151 kHz repetition rate at the absorbed pump power of 6.48 W. Such a radially polarized pulse would facilitate numerous applications.

  19. Laser based analysis using a passively Q-switched laser employing analysis electronics and a means for detecting atomic optical emission of the laser media

    Science.gov (United States)

    Woodruff, Steven D.; Mcintyre, Dustin L.

    2016-03-29

    A device for Laser based Analysis using a Passively Q-Switched Laser comprising an optical pumping source optically connected to a laser media. The laser media and a Q-switch are positioned between and optically connected to a high reflectivity mirror (HR) and an output coupler (OC) along an optical axis. The output coupler (OC) is optically connected to the output lens along the optical axis. A means for detecting atomic optical emission comprises a filter and a light detector. The optical filter is optically connected to the laser media and the optical detector. A control system is connected to the optical detector and the analysis electronics. The analysis electronics are optically connected to the output lens. The detection of the large scale laser output production triggers the control system to initiate the precise timing and data collection from the detector and analysis.

  20. Minocycline-induced hyperpigmentation: comparison of 3 Q-switched lasers to reverse its effects

    Directory of Open Access Journals (Sweden)

    Nisar MS

    2013-05-01

    Full Text Available Mahrukh S Nisar,1 Karthik Iyer,1 Robert T Brodell,2 Jenifer R Lloyd,3 Thuzar M Shin,3 Asad Ahmad4 1Northeast Ohio Medical University, Rootstown, OH, USA; 2Division of Dermatology, University of Mississippi Medical Center, Jackson, MS, USA; 3Case Western Reserve University School of Medicine, Cleveland, OH, USA; 4Northside Medical Center, Youngstown, OH, USA Abstract: Minocycline is a tetracycline derivative antibiotic commonly prescribed for acne, rosacea, and other inflammatory skin disorders. Minocycline turns black when oxidized, leading to discoloration of the skin, nails, bulbar conjunctiva, oral mucosa, teeth, bones, and thyroid gland. Hyperpigmentation has been reported after long-term minocycline therapy with at least 100 mg/day. Three types of minocycline-induced cutaneous hyperpigmentation can result. Type I is the most common, and is associated with blue-black discoloration in areas of previous inflammation and scarring. Type II most commonly affects the legs and is characterized by blue-gray pigmentation of previously normal skin. Type III is the least common and is characterized by diffuse muddy-brown discoloration predominantly on sun exposed skin. Minocycline-induced hyperpigmentation may be cosmetically disfiguring and prompt identification is essential. Without treatment, symptoms may take several months, to years to resolve, after discontinuation of the drug. However, the pigmentation may never completely disappear. In fact, there have been few reports of complete resolution associated with any therapeutic intervention. We report a case of a patient on long-term minocycline therapy utilized as an anti-inflammatory agent to control symptoms of rheumatoid arthritis, which led to minocycline-induced hyperpigmentation of the face. To remove the blue-gray cutaneous deposits, 3 Q-switched lasers (Neodymium: yttrium aluminum garnet (Nd:YAG 1064 nm, Alexandrite 755 nm, and Ruby 694 nm were used in test areas. The Alexandrite 755 nm

  1. Q-switched Nd:YAG/V:YAG microchip 1338 nm laser for laser-induced breakdown spectroscopy

    Science.gov (United States)

    Šulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

    2017-12-01

    Q-switched microchip laser emitting radiation at wavelength 1338nm was tested as a radiation source for laser induced breakdown spectroscopy (LIBS). This laser used sandwich crystal which combined in one piece the cooling part (undoped YAG crystal 4mm long), the active laser part (Nd:YAG crystal 12mm long), and the saturable absorber (V:YAG crystal 0.7mm long). The diameter of this crystal was 5 mm. The microchip resonator consisted of dielectric mirrors directly deposited on the monolith crystal surfaces. The pump mirror (HT @ 808 nm, HR @ 1.3 ¹m) was placed on the undoped YAG part. The output coupler (R = 90% @ 1338 nm) was placed on the V:YAG part. The fibre-coupled 808nm pumping laser diode was operating in pulsed regime (rep. rate 250 Hz, pulse width 300 ¹s, pulse energy 6 mJ). Using this pumping, stable and high reproducible Q-switched pulses were generated at wavelength 1338 nm. Pulse length was 6.2 ns (FWHM) and the mean output power was 33mW. The single pulse energy and peak power was 0.13mJ and 21kW, respectively. Laser was operating in fundamental TEM00 mode. The laser radiation was focused on a tested sample using single plano-convex lens (focal length 75 mm). The focal spot radius was 40 ¹m. The corresponding peak-power density was 0.83GW/cm2. The laser induced break-down was successfully reached and corresponding laser-induced plasma spectra were recorded for set of metallic elements (Cu, Ag, Au, In, Zn, Al, Fe, Ni, Cr) and alloys (Sn-Pb solder, duralumin, stainless-steel, brass). To record the spectra, StellarNet BLACK-Comet concave grating CCD-based spectrometer was used without any special collimation optics. Thanks to used laser wavelength far from the detector sensitivity, no special filtering was needed to overcome the CCD dazzling. The constructed laser could significantly improve repletion-rate of up-to-date LIBS devices.

  2. 36 W Q-switched Ho:YAG laser at 2097 nm pumped by a Tm fiber laser: evaluation of different Ho3+ doping concentrations

    Science.gov (United States)

    Antipov, O. L.; Eranov, I. D.; Kositsyn, R. I.

    2017-01-01

    A laser oscillator based on Ho:YAG crystal pumped by a Tm fiber laser with an acousto-optical Q-switch was optimized for maximum output power and pulse-to-pulse stability. Stable operation at 2097 nm in Q-switched mode is demonstrated, with pulse repetition rates from 10 to 30 kHz, and output power of 36 W (at 55 W of pump power at 1908 nm) in the good quality beam. The influence of Ho ion up-conversion and thermal lensing on the oscillation efficiency is discussed.

  3. Q-switched Erbium-doped fiber laser at 1600 nm for photoacoustic imaging application

    Energy Technology Data Exchange (ETDEWEB)

    Piao, Zhonglie [Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Beckman Laser Institute, Department of Biomedical Engineering, University of California, Irvine, California 92612 (United States); Zeng, Lvming; Chen, Zhongping, E-mail: z2chen@uci.edu, E-mail: ckim@pusan.ac.kr [Beckman Laser Institute, Department of Biomedical Engineering, University of California, Irvine, California 92612 (United States); Kim, Chang-Seok, E-mail: z2chen@uci.edu, E-mail: ckim@pusan.ac.kr [Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

    2016-04-04

    We present a nanosecond Q-switched Erbium-doped fiber (EDF) laser system operating at 1600 nm with a tunable repetition rate from 100 kHz to 1 MHz. A compact fiber coupled, acousto-optic modulator-based EDF ring cavity was used to generate a nanosecond seed laser at 1600 nm, and a double-cladding EDF based power amplifier was applied to achieve the maximum average power of 250 mW. In addition, 12 ns laser pulses with the maximum pulse energy of 2.4 μJ were obtained at 100 kHz. Furthermore, the Stokes shift by Raman scattering over a 25 km long fiber was measured, indicating that the laser can be potentially used to generate the high repetition rate pulses at the 1.7 μm region. Finally, we detected the photoacoustic signal from a human hair at 200 kHz repetition rate with a pulse energy of 1.2 μJ, which demonstrates that a Q-switched Er-doped fiber laser can be a promising light source for the high speed functional photoacoustic imaging.

  4. High peak power Q-switched Er:YAG laser with two polarizers and its ablation performance for hard dental tissues.

    Science.gov (United States)

    Yang, Jingwei; Wang, Li; Wu, Xianyou; Cheng, Tingqing; Jiang, Haihe

    2014-06-30

    An electro-optically Q-switched high-energy Er:YAG laser with two polarizers is proposed. By using two Al(2)O(3) polarizing plates and a LiNbO(3) crystal with Brewster angle, the polarization efficiency is significantly improved. As a result, 226 mJ pulse energy with 62 ns pulse width is achieved at the repetition rate of 3 Hz, the corresponding peak power is 3.6 MW. To our knowledge, such a high peak power has not been reported in literature. With our designed laser, in-vitro teeth were irradiated under Q-switched and free-running modes. Results of a laser ablation experiment on hard dental tissue with the high-peak-power laser demonstrates that the Q-switched Er:YAG laser has higher ablation precision and less thermal damage than the free-running Er:YAG laser.

  5. 2 and 3 µm passively Q-switched bulk pulse laser based on a MoS2/graphene heterojunction

    Science.gov (United States)

    Wang, Xihu; Xu, Jinlong; Sun, Yijian; Feng, Wendou; You, Zhenyu; Sun, Dunlu; Tu, Chaoyang

    2018-01-01

    We report for the first time that a MoS2/graphene heterojunction can behave as a saturable absorber to realize 2 and 3 µm passively Q-switched bulk lasers. This heterojunction is prepared through a facile hydrothermal method. For the 2 µm laser, a stable pulse is obtained with a pulse duration of 473 ns, output power of 553 mW, pulse energy of 5.267 µJ and repetition rate of 105 kHz. For the 3 µm laser, a pulse duration of 355 ns is observed with an average output power of 112 mW and pulse energy of 0.889 µJ. These results indicate the great potential of MoS2/graphene heterojunctions for realizing mid-infrared pulse lasers.

  6. Q-switched all-solid-state lasers and application in processing of thin-film solar cell

    Science.gov (United States)

    Liu, Liangqing; Wang, Feng

    2009-08-01

    Societal pressure to renewable clean energy is increasing which is expected to be used as part of an overall strategy to address global warming and oil crisis. Photovoltaic energy conversion devices are on a rapidly accelerating growth path driven by government, of which the costs and prices lower continuously. The next generation thin-film devices are considered to be more efficiency and greatly reduced silicon consumption, resulting in dramatically lower per unit fabrication costs. A key aspect of these devices is patterning large panels to create a monolithic array of series-interconnected cells to form a low current, high voltage module. This patterning is accomplished in three critical scribing processes called P1, P2, and P3. All-solid-state Q-switched lasers are the technology of choice for these processes, due to their advantages of compact configuration, high peak-value power, high repeat rate, excellent beam quality and stability, delivering the desired combination of high throughput and narrow, clean scribes. The end pumped all-solid-state lasers could achieve 1064nm IR resources with pulse width of nanoseconds adopting acoustic-optics Q-switch, shorter than 20ns. The repeat rate is up to 100kHz and the beam quality is close to diffraction limit. Based on this, 532nm green lasers, 355nm UV lasers and 266nm DUV lasers could be carried out through nonlinear frequency conversion. Different wave length lasers are chose to process selective materials. For example, 8-15 W IR lasers are used to scribe the TCO film (P1); 1-5 W green lasers are suitable for scribing the active semiconductor layers (P2) and the back contact layers (P3). Our company, Wuhan Lingyun Photo-electronic System Co. Ltd, has developed 20W IR and 5W green end-pumped Q-switched all-solid-state lasers for thin-film solar industry. Operating in high repeat rates, the speed of processing is up to 2.0 m/s.

  7. Fractional CO2 laser is as effective as Q-switched ruby laser for the initial treatment of a traumatic tattoo.

    Science.gov (United States)

    Seitz, Anna-Theresa; Grunewald, Sonja; Wagner, Justinus A; Simon, Jan C; Paasch, Uwe

    2014-12-01

    Q-switched laser treatments are considered the standard method for removing both regular and traumatic tattoos. Recently, the removal of tattoo ink using ablative fractional lasers has been reported. Ablative fractional CO2 laser and q-switched ruby laser treatments were used in a split-face mode to compare the safety and efficacy of the two types of laser in removing a traumatic tattoo caused by the explosion of a firework. A male patient suffering from a traumatic tattoo due to explosive deposits in his entire face was subjected to therapy. A series of eleven treatments were performed. The right side of the face was always treated using an ablative fractional CO2 laser, whereas the left side was treated only using a q-switched ruby laser. After a series of eleven treatments, the patient demonstrated a significant lightening on both sides of his traumatic tattoo, with no clinical difference. After the first six treatments, the patient displayed greater lightening on the right side of his face, whereas after another five treatments, the left side of the patient's face appeared lighter. No side effects were reported. In the initial stage of removing the traumatic tattoo, the ablative fractional laser treatment appeared to be as effective as the standard ruby laser therapy. However, from the 6th treatment onward, the ruby laser therapy was more effective. Although ablative fractional CO2 lasers have the potential to remove traumatic tattoos, they remain a second-line treatment option.

  8. Watt-level passively Q-switched double-cladding fiber laser based on graphene oxide saturable absorber.

    Science.gov (United States)

    Yu, Zhenhua; Song, Yanrong; Dong, Xinzheng; Li, Yanlin; Tian, Jinrong; Wang, Yonggang

    2013-10-10

    A watt-level passively Q-switched ytterbium-doped double-cladding fiber laser with a graphene oxide (GO) absorber was demonstrated. The structure of the GO saturable absorber mirror (GO-SAM) was of the sandwich type. A maximum output power of 1.8 W was obtained around a wavelength of 1044 nm. To the best of our knowledge, this is the highest output power in Q-switched fiber lasers based on a GO saturable absorber. The pure GO was protected from the oxygen in the air so that the damage threshold of the GO-SAM was effectively raised. The gain fiber was a D-shaped ytterbium-doped double-cladding fiber. The pulse repetition rates were tuned from 120 to 215 kHz with pump powers from 3.89 to 7.8 W. The maximum pulse energy was 8.37 μJ at a pulse width of 1.7 μs.

  9. Performance of continuous wave and acousto-optically Q-switched Tm, Ho: YAP laser pumped by diode laser

    Science.gov (United States)

    Li, Guoxing; Xie, Wenqiang; Yang, Xining; Zhang, Ziqiu; Zhang, Hongda; Zhang, Liang

    2018-02-01

    A two-end-pumped a-cut Tm(0.5%), Ho(0.5%):YAP laser output at 2119nm is reported under cryogenic temperature. The maximum output power reached to 7.76W with the incident pump power of 24.2W in CW mode. With the acousto-optically Q-switch, an average power of 7.3W can be obtained, when the pulse repetition frequency was 7.5 kHz. The corresponding optical-to-optical conversion efficiency was 30.2% and the slope efficiency was 31.4%. Then, the laser output characteristics in the repetition frequency of 7.5 kHz and 10kHz were researched. The output power, the optical-to-optical conversion efficiency and slope efficiency were increased with the increase of the repetition frequency. In the same repetition frequency, the pulse duration was decreasing with the growth of the incident pump power.

  10. Treatment of Laugier-Hunziker syndrome with the Q-switched alexandrite laser in 22 Chinese patients.

    Science.gov (United States)

    Zuo, Ya-Gang; Ma, Dong-Lai; Jin, Hong-Zhong; Liu, Yue-Hua; Wang, Hong-Wei; Sun, Qiu-Ning

    2010-03-01

    Laugier-Hunziker syndrome (LHS), a rare, acquired pigmentary disorder of the lips, oral mucosa, and fingers, is known to be an entirely benign disease with no systemic manifestations. In the past, the pigmentation has been treated efficiently in a few patients with the Q-switched neodymium: yttrium-aluminum-garnet (Nd:YAG) laser and the Q-switched alexandrite laser (QSAL). In order to evaluate the efficacy and safety of QSAL on Chinese patients of LHS, we treated 22 patients with QSAL in the past 5 years. Treatments were delivered on a bimonthly or trimonthly basis until the abnormal pigmentation totally disappeared. Patients were evaluated at each visit for evidence of dyspigmentation, scarring, or other untoward effects from the laser treatment. Our 22 subjects consisted of 18 females and 4 males with a mean age of 42.4 years. After only one session of laser treatment, the clearing on the lips was as follow: 18 (81.8%) excellent, 2 (9.1%) good, 1 (4.5%) fair and 1 (4.5%) poor. Eighteen patients (81.8%) with LHS, who had achieved excellent clearing after only one session of laser treatment, did not receive further treatment. Among the left four patients, three patients (13.6%) achieved complete results after three laser treatments. Only one patient required six sessions to achieve complete clearance. No scarring was noted after any of the treatments. The appearance of pigmentation on mucous membranes in a middle-aged patient without a significant family history for skin disorders should prompt consideration for the possible diagnosis of LHS. Our study has also demonstrated QSAL to be highly effective and safe in the treatment of LHS.

  11. High-energy azimuthally polarized laser beam generation from an actively Q-switched Nd:YAG laser with c-cut YVO4 crystal

    Science.gov (United States)

    Guo, Jing; Zhang, Baofu; Jiao, Zhongxing; He, Guangyuan; Wang, Biao

    2018-05-01

    A high-energy, azimuthally polarized (AP) and actively Q-switched Nd:YAG laser is demonstrated. The thermal bipolar lensing effect in the Nd:YAG laser rod is used as a polarization discriminator, and a c-cut YVO4 crystal is inserted into the laser cavity to increase the mode-selecting ability of the cavity for AP mode. The laser generated AP pulses with maximum pulse energy as high as 4.2 mJ. To the best of our knowledge, this is the highest pulse energy obtained from an actively Q-switched AP laser. The pulse energy remained higher than 1 mJ over a wide range of repetition rates from 5 kHz to 25 kHz.

  12. Comparison of two Q-switched lasers and a short-pulse erbium-doped yttrium aluminum garnet laser for treatment of cosmetic tattoos containing titanium and iron in an animal model.

    Science.gov (United States)

    Wang, Chia-Chen; Huang, Chuen-Lin; Yang, An-Hang; Chen, Chih-Kang; Lee, Shao-Chen; Leu, Fur-Jiang

    2010-11-01

    Cosmetic tattoos contain titanium and ferric oxide and darken through reduction after Q-switched laser irradiation. The optimal treatment for removing these pigments remains unknown. To compare the effects of two Q-switched lasers and a short-pulse erbium-doped yttrium aluminum garnet (SP Er:YAG) laser to remove cosmetic tattoos in an animal model. Rats were tattooed using white, flesh-colored, and brown inks (4 bands of each color) on their backs. For each color, one band was left untreated, and one each was treated with a Q-switched neodymium-doped YAG laser, a Q-switched alexandrite laser, and a SP Er:YAG laser every 3 weeks until the pigments were clear. The two Q-switched lasers were equally effective; all three pigments darkened initially and then resolved gradually. Up to 20, 18, and 10 sessions were required to remove white, flesh-colored, and brown tattoos, respectively. Only six sessions were required with the SP Er:YAG laser. Minimal scarring was observed with all lasers. Skin biopsies confirmed pigment granule fragmentation after Q-switched laser treatment and a decrease in the amount of pigment after SP Er:YAG laser treatment. The SP Er:YAG laser was superior to the Q-switched lasers for removing cosmetic tattoos. © 2010 by the American Society for Dermatologic Surgery, Inc.

  13. Diode-pumped passively Q-switched Nd:GdTaO4 laser based on tungsten disulfide nanosheets saturable absorber at 1066 nm

    Science.gov (United States)

    Li, M. X.; Jin, G. Y.; Li, Y.

    2018-05-01

    In this paper, we investigated the passively Q-switched Nd:GdTaO4 laser based on tungsten disulfide (WS2) saturable absorber (SA). The preparation method of WS2 SA was to attach the WS2-alcohol dispersion onto the quartz substrates. The diode-pumped passively Q-switched Nd:GdTaO4 laser operated at a central wavelength of 1066 nm. The stable pulse output could be obtained at the single pulse width of 560 ns. In a word, WS2 seems to be a suitable saturable absorber for solid state lasers.

  14. Photobiomodulation therapy on wound treatment subsequent to Q-switched Nd: YAG laser tattoo removal in rat model.

    Science.gov (United States)

    Imrigha, Nada Abusalah Almabrouk; Bidin, Noriah; Lau, Pik Suan; Musa, Nurfatin; Zakaria, Nurlaily; Krishnan, Ganesan

    2017-10-01

    Q-switched Nd: YAG laser is the most effective laser for tattoo removal. Photobiomodulation (PBM) therapy is an alternative method applied to accelerate the wound healing. This paper investigated the effects of PBM therapy using 808 nm diode laser on tattooed skin after laser tattoo removal. Forty-five rats were selected and tattooed with black ink on their dorsal, and then distributed into three groups. G0 was received non-laser irradiation. G1 was treated by laser tattoo removal using 1064 nm with energy density of 3.4 J/cm 2 without PBM therapy, while G2 was treated daily with PBM therapy using 808 nm diode laser of 5 J/cm 2 after a single session of laser tattoo removal. The effects of tattoo removal and healing progress of the wound were analyzed using histological studies. Findings showed 808 nm laser promotes the healing process through enhancing epithelialization and collagen deposition. Moreover, PBM therapy stimulated immune cells to improve phagocytosis process for removing the tattoo ink fragments effectively. The PBM therapy treated group was capable of improving the healing process and increasing the quality of skin following the laser tattoo removal. It was also found that stimulation of cellular function by PBM therapy increased tattoo clearance efficiency. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Q-switching and efficient harmonic generation from a single-mode LMA photonic bandgap rod fiber laser

    DEFF Research Database (Denmark)

    Laurila, Marko; Saby, Julien; Alkeskjold, Thomas T.

    2011-01-01

    We demonstrate a Single-Mode (SM) Large-Mode-Area (LMA) ytterbium-doped PCF rod fiber laser with stable and close to diffraction limited beam quality with 110W output power. Distributed-Mode-Filtering (DMF) elements integrated in the cladding of the rod fiber provide a robust spatial mode...... with a Mode-Field-Diameter (MFD) of 59 mu m. We further demonstrate high pulse energy Second-Harmonic-Generation (SHG) and Third Harmonic Generation (THG) using a simple Q-switched single-stage rod fiber laser cavity architecture reaching pulse energies up to 1mJ at 515nm and 0.5mJ at 343nm. (C) 2011 Optical...

  16. Highly efficient actively Q-switched Yb:LGGG laser generating 3.26 mJ of pulse energy

    Science.gov (United States)

    Li, Yanbin; Zhang, Jian; Zhao, Ruwei; Zhang, Baitao; He, Jingliang; Jia, Zhitai; Tao, Xutang

    2018-05-01

    An efficient acousto-optic Q-switched laser operation of Yb:(LuxGd1-x)3Ga5O12 (x = 0.062) (Yb:LGGG) crystal is demonstrated, producing stable pulses with repetition rate ranging from 1 to 20 kHz. Under the absorbed pump power of 8.75 W, the maximum average output power of 3.26 W is obtained at the pulse repletion rate of 1 kHz, corresponding to the slope efficiency as high as 52%. The pulse width of 14.5 ns is achieved with the pulse energy and peak power of 3.26 mJ and 225 kW, respectively. It indicates great potential of Yb:LGGG crystal for generating pulsed lasers.

  17. Passively Q-switched self-frequency-doubled Nd3+:GdCa4O(BO3)3 laser

    International Nuclear Information System (INIS)

    Zhang, Xingyu; Zhao, Shengzhi; Wang, Qingpu; Zhang, Shujun; Sun, Lianke; Liu, Xunmin; Zhang, Shaojun; Chen, Huanchu

    2001-01-01

    The performance of a flash-lamp-pumped self-frequency-doubled Nd 3+ :GdCa 4 O(BO 3 ) 3 (Nd:GdCOB) laser that is passively Q switched with Cr 4+ :YAG saturable absorbers is demonstrated. The maximum 0.53-μm pulse energy obtained is 2.6 mJ, and the maximum peak intensity is 15 MW/cm2. The dependence of the pulse characteristics on the orientation of the saturable absorber and on the cavity length is measured. Meanwhile, the transversal distribution of the intracavity photon density is taken into account in the rate equations for an intracavity frequency-doubled passively Q-switched laser, and the solutions are used to account for the behavior of the passively Q-switched Nd:GdCOB laser. [copyright] 2001 Optical Society of America

  18. Development of a compact vertical-cavity surface-emitting laser end-pumped actively Q-switched laser for laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuo; Chen, Rongzhang; Nelsen, Bryan; Chen, Kevin, E-mail: pec9@pitt.edu [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Liu, Lei; Huang, Xi; Lu, Yongfeng [Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)

    2016-03-15

    This paper reports the development of a compact and portable actively Q-switched Nd:YAG laser and its applications in laser-induced breakdown spectroscopy (LIBS). The laser was end-pumped by a vertical-cavity surface-emitting laser (VCSEL). The cavity lases at a wavelength of 1064 nm and produced pulses of 16 ns with a maximum pulse energy of 12.9 mJ. The laser exhibits a reliable performance in terms of pulse-to-pulse stability and timing jitter. The LIBS experiments were carried out using this laser on NIST standard alloy samples. Shot-to-shot LIBS signal stability, crater profile, time evolution of emission spectra, plasma electron density and temperature, and limits of detection were studied and reported in this paper. The test results demonstrate that the VCSEL-pumped solid-state laser is an effective and compact laser tool for laser remote sensing applications.

  19. All passive synchronized Q-switching of a quasi-three-level and a four-level Nd:YAG laser

    DEFF Research Database (Denmark)

    Cheng, Haynes Pak Hay; Tidemand-Lichtenberg, Peter; Jensen, Ole Bjarlin

    2010-01-01

    Using an all passive approach, synchronized Q-switching of two Nd:YAG lasers, at 946 nm and 1064 nm, is reported. Two laser crystals are used to avoid gain competition, and stable operation is reported for the first time. The pulse trains are synchronized over a wide range of pump powers...

  20. The simultaneous generation of soliton bunches and Q-switched-like pulses in a partially mode-locked fiber laser with a graphene saturable absorber

    Science.gov (United States)

    Wang, Zhenhong; Wang, Zhi; Liu, Yan-ge; He, Ruijing; Wang, Guangdou; Yang, Guang; Han, Simeng

    2018-05-01

    We experimentally report the coexistence of soliton bunches and Q-switched-like pulses in a partially mode-locked fiber laser with a microfiber-based graphene saturable absorber. The soliton bunches, like isolated spikes with extreme amplitude and ultrashort duration, randomly generate in the background of the Q-switched-like pulses. The soliton bunches have some pulse envelopes in which pulses operate at a fundamental repetition rate in the temporal domain. Further investigation shows that the composite pulses are highly correlated with the noise-like pulses. Our work can make a further contribution to enrich the understanding of the nonlinear dynamics in fiber lasers.

  1. Split-face comparison of intense pulsed light and nonablative 1,064-nm Q-switched laser in skin rejuvenation.

    Science.gov (United States)

    Huo, Meng-Hua; Wang, Yong-Qian; Yang, Xin

    2011-01-01

    Multiple nonablative skin rejuvenation techniques have been used to improve facial aging. To compare rejuvenation efficiency of intense pulsed light (IPL) with nonablative 1,064-nm Q-switched laser in Asian patients. Twelve female subjects were enrolled and received five sessions of treatments at 2-week intervals. A split-face study was performed, with IPL applied to the left side of the face and nonablative 1,064-nm Q-switched laser to the right side. All assessments showed significant skin rejuvenation. For the improvement of skin texture, pore size, and sebum secretion, similar efficiency from laser and IPL was observed. For lightening of skin tone and macula, the IPL was more efficient than the laser after the first treatment, although no further clinical improvement resulted after three treatments. The laser gradually lightened the skin tone and macula and was ultimately more efficient than the IPL after five treatments. A series of IPL and nonablative 1,064-nm Q-switched laser treatments were performed with similar efficiency and safety for the improvement in skin texture, pore size, and sebum secretion. IPL was faster, but nonablative 1,064-nm Q-switched laser was more effective in improving skin tone and macula. © 2010 by the American Society for Dermatologic Surgery, Inc.

  2. Nerve fiber layer (NFL) degeneration associated with acute q-switched laser exposure in the nonhuman primate

    Science.gov (United States)

    Zwick, Harry; Zuclich, Joseph A.; Stuck, Bruce E.; Gagliano, Donald A.; Lund, David J.; Glickman, Randolph D.

    1995-01-01

    We have evaluated acute laser retinal exposure in non-human primates using a Rodenstock scanning laser ophthalmoscope (SLO) equipped with spectral imaging laser sources at 488, 514, 633, and 780 nm. Confocal spectral imaging at each laser wavelength allowed evaluation of the image plane from deep within the retinal vascular layer to the more superficial nerve fiber layer in the presence and absence of the short wavelength absorption of the macular pigment. SLO angiography included both fluorescein and indocyanine green procedures to assess the extent of damage to the sensory retina, the retinal pigment epithelium (RPE), and the choroidal vasculature. All laser exposures in this experiment were from a Q-switched Neodymium laser source at an exposure level sufficient to produce vitreous hemorrhage. Confocal imaging of the nerve fiber layer revealed discrete optic nerve sector defects between the lesion site and the macula (retrograde degeneration) as well as between the lesion site and the optic disk (Wallerian degeneration). In multiple hemorrhagic exposures, lesions placed progressively distant from the macula or overlapping the macula formed bridging scars visible at deep retinal levels. Angiography revealed blood flow disturbance at the retina as well as at the choroidal vascular level. These data suggest that acute parafoveal laser retinal injury can involve both direct full thickness damage to the sensory and non-sensory retina and remote nerve fiber degeneration. Such injury has serious functional implications for both central and peripheral visual function.

  3. Simultaneous Q-switching and mode-locking in an intracavity frequency doubled diode-pumped Nd:YVO4 / KTP green laser with Cr4+:YAG

    International Nuclear Information System (INIS)

    Mukhopadhyay, P. K.; Ranganathan, K.; George, J.; Nathan, T. P. S.; Alsous, M. B.

    2007-01-01

    We report intracavity second harmonic (at 532 nm) generation in passively Q-switched mode-locked Nd: YVO4 laser. The width of a typical Q-switched envelope of the mode locked pulses for the green laser was around 65 ± 5 ns and the repetition rate for the mode locked pulses was 400 MHz. The intracavity frequency doubling significantly improves the depth of modulation of the mode locked pulses. The peak power of a single mode locked green pulse near the center of the Q-switched envelope was estimated to be more than 2kw and the average green power was 6 times higher than the CW green power at an incident diode pump power of 6W. (author)

  4. Severe unexpected adverse effects after permanent eye makeup and their management by Q-switched Nd:YAG laser.

    Science.gov (United States)

    Goldman, Alberto; Wollina, Uwe

    2014-01-01

    Permanent makeup is a cosmetic tattoo that is used to enhance one's appearance, and which has become more popular among middle-aged and elderly women. A couple of benefits seem to be associated with permanent tattoos in the elderly: saving time (wake up with makeup); poor eyesight (difficult to apply makeup); and saving money. On the other hand, cosmetic tattoos bear the same risks as other tattoo procedures. We report on fading and unintended hyperpigmentation after tattooing on eyebrows and eyelids, and discuss the scientific and anatomical background behind the possible cause. Dermatochalasis may be a possible risk factor for excessive unwanted discolorations. Q-switched neodymium-doped yttrium aluminum garnet laser is an appropriate and safe therapeutic tool that can manage such adverse effects. Consumer protection warrants better information and education of the risks of cosmetic tattoos - in particular, for elderly women.

  5. On the densification and hydration of CaCO3 particles by Q-switched laser pulses in water

    Science.gov (United States)

    Lin, Peng-Wen; Wu, Chao-Hsien; Zheng, Yuyuan; Chen, Shuei-Yuan; Shen, Pouyan

    2013-09-01

    Calcite powders subjected to Q-switched laser pulses in water were characterized by X-ray/electron diffraction and optical spectroscopy to have a significant internal compressive stress (up to ca. 1.5 GPa) with accompanied transformation into defective calcite II and hydrates. The defective calcite II particles were (0 1 0), (0 0 1), (0 1¯ 1), (0 1 3) and (0 1¯ 3) faceted with 2×(0 2 0)II commensurate superstructure and tended to hydrate epitaxially as monohydrocalcite co-existing with ikaite (CaCO3·6H2O) with extensive cleavages and amorphous calcium carbonate with porous structure. The colloidal suspension containing the densified calcite polymorphs and hydrates showed two UV-visible absorptions corresponding to a minimum band gap of ca. 5 and 3 eV, respectively.

  6. Dynamical modeling and experiment for an intra-cavity optical parametric oscillator pumped by a Q-switched self-mode-locking laser

    Science.gov (United States)

    Wang, Jing; Liu, Nianqiao; Song, Peng; Zhang, Haikun

    2016-11-01

    The rate-equation-based model for the Q-switched mode-locking (QML) intra-cavity OPO (IOPO) is developed, which includes the behavior of the fundamental laser. The intensity fluctuation mechanism of the fundamental laser is first introduced into the dynamics of a mode-locking OPO. In the derived model, the OPO nonlinear conversion is considered as a loss for the fundamental laser and thus the QML signal profile originates from the QML fundamental laser. The rate equations are solved by a digital computer for the case of an IOPO pumped by an electro-optic (EO) Q-switched self-mode-locking fundamental laser. The simulated results for the temporal shape with 20 kHz EO repetition and 11.25 W pump power, the signal average power, the Q-switched pulsewidth and the Q-switched pulse energy are obtained from the rate equations. The signal trace and output power from an EO QML Nd3+: GdVO4/KTA IOPO are experimentally measured. The theoretical values from the rate equations agree with the experimental results well. The developed model explains the behavior, which is helpful to system optimization.

  7. A retrospective analysis of the influencing factors and complications of Q-switched lasers in tattoo removal in China.

    Science.gov (United States)

    Zhang, Mengli; Gong, Xiangdong; Lin, Tong; Wu, Qiuju; Ge, Yiping; Huang, Yuqing; Ge, LiYu

    2018-04-01

    Q-switched (QS) lasers are the gold standard for tattoo removal. The purpose of the present study was to gain a more comprehensive understanding of the factors that influence the efficacy of QS lasers and their associated complications in the removal of tattoos in China. Clinical data of 266 patients were analyzed retrospectively. The tattoo clearance rate was evaluated using the 4-point scale. The Cox regression model was applied to analyze the factors that affected the efficacy of QS lasers in tattoo removal. In addition, treatment-related adverse reactions were analyzed. The results showed that several variables had a statistically significant effect (p tattoo removal treatment, including the patients' age, the tattoo's age, type, color, or ink density and the number of treatments. A variety of adverse responses occurred during the laser treatment. The overall incidence of adverse responses was approximately 24.06%, including pigmentation, hypopigmentation, bulla formation, allergic reactions, and skin texture changes or hypertrophic scarring. Some factors may influence the efficacy of QS lasers in the treatment of tattoos and certain adverse reactions may occur during this process.

  8. Passively Q-switched mode-locked Nd3+:LuVO4 laser by LT-GaAs saturable absorber

    International Nuclear Information System (INIS)

    Li, M; Zhao, S; Li, Y; Yang, K; Li, G; Li, D; An, J; Li, T; Yu, Z

    2009-01-01

    By using LT-GaAs as saturable absorber, we have demonstrated the stable Q-switched and mode-locked (QML) Nd:LuVO 4 laser run in a Z-type folded cavity. Nearly 100% modulation depth of mode locking can be obtained as long as the pump power reaches the oscillation threshold. The repetition rate of the passively Q-switched pulse envelops ranges from 37.5 to 139 kHz as the pump power increased from 1.7 to 8.2 W. The mode-locked pulse inside the Q-switched envelop has an estimated pulse width of about 220 ps and a repetition rate of 111 MHz. Under an incident pump power of 8.2 W, the highest pulse energy of 6 μJ of each Q-switched envelope, and the highest peak power about 2.73 kW of Q-switched mode-locked pulses can be obtained

  9. Diode-pumped continuous-wave and passively Q-switched Nd:GdLuAG laser at 1443.9 nm

    Science.gov (United States)

    Wu, Qianwen; Liu, Zhaojun; Zhang, Sasa; Cong, Zhenghua; Guan, Chen; Xue, Feng; Chen, Hui; Huang, Qingjie; Xu, Xiaodong; Xu, Jun; Qin, Zengguang

    2017-12-01

    We investigated the 1443.9 nm laser characteristics of Nd:GdLuAG crystal. Diode-end-pumping configuration was employed under both continuous-wave (CW) and passively Q-switched operations. For CW operation, the maximum average output power was 1.36 W with a slope efficiency of 15%. By using a V3+:YAG crystal as the saturable absorber, we obtained the maximum average output power of 164 mW under Q-switched operation. The corresponding pulse energy was 29.3 μJ and pulse duration was 59 ns.

  10. The regeneration of thermal wound on mice skin (Mus Musculus) after Q-Switch Nd: YAG laser irradiation for cancer therapy candidate

    Science.gov (United States)

    Apsari, R.; Nahdliyatun, E.; Winarni, D.

    2017-09-01

    The aims of this study are to investigate the regeneration of mice skin tissue (Mus Musculus) irradiated by Q-Switch Nd: YAG laser and morphological change due to Q-Switch Nd: YAG laser irradiation compared to conventional heating (hairdryer). The 2-3 month of twenty-seven mice were used for experimental animals. Mice were incised in the dorsum by the damage effect of laser energy dose (therapeutic dose) of 29.5 J/cm2 with 10 seconds of exposure time, 10 Hz of repetition rate, and 100 pulses of the given single pulse energy. The mice skin tissue was injuried by hairdryer to get burned effect. Mice were divided into three groups, Group I (control) were not treated by anything, Group II were treated by Q-Switch Nd: YAG laser irradiation and sacrificed on (0, 1, 3, 5) days, and Group III were treated by hairdryer then sacrificed on (0, 1, 3, 5) days. Pathology examination showed that the energy of 29,5 J/cm2 dose produced the hole effect (ablation) through the hypodermic layer caused by optical breakdown and collagen coagulation. Thus, the 60 °C temperature of burn showed coagulation necrosis because piknosis discovered in the injured area. The regeneration process showed that the mice skin tissue's ability to regenerate was irradiated by fast laser because of the focus of Q-Switch Nd: YAG laser. It was showed by the scab releases on third day and completely reepithelialization formation on the fifth day. The collagen fibers distribution was same as normal skin tissue on day 5 and so did angiogenesis. Therefore, Q-Switch Nd: YAG laser can be applied for problems of dermatology medical therapies, especially melasma, nevus of ota and tatto therapy. For skin cancer therapy application, energy dose of unregenerated skin tissue is chosen because the death expected effect is permanent.

  11. Effects of adding metals to MoS2 in a ytterbium doped Q-switched fiber laser

    Science.gov (United States)

    Khaleque, Abdul; Liu, Liming

    2018-03-01

    Molybdenum disulfide (MoS2) is widely used in lubricants, metallic alloys and in electronic and optical components. It is also used as saturable absorbers (SAs) in lasers (e.g. fiber lasers): a simple deposition of MoS2 on the fiber end can create a saturable absorber without the necessity of extensive alignment of the optical beam. In this article, we study the effects of adding different metals (Cr, Au, and Al) to MoS2 in a ytterbium (Yb)-doped Q-switched fiber laser. Experimental results show that the addition of a thin layer of gold and aluminium can reduce pulse durations to about 5.8 μs and 8.5 μs, respectively, compared with pure MoS2 with pulse duration of 12 μs. Experimental analysis of the combined metal and MoS2 based composite SAs can be useful in fiber laser applications where it may also find applications in medical, three dimensional (3D) active imaging and dental applications.

  12. High speed ink aggregates are ejected from tattoos during Q-switched Nd:YAG laser treatments.

    Science.gov (United States)

    Murphy, Michael J

    2018-03-25

    Dark material has been observed embedded within glass slides following Q-switched Nd:YAG laser treatment of tattoos. It appears that these fragments are ejected at high speed from the skin during the treatment. Light microscopic analysis of the slides reveals aggregates of dark fragmented material, presumably tattoo ink, with evidence of fractured/melted glass. Photomicrographs reveal that the sizes of these aggregates are in the range 12 μm to 0.5 mm. Tattoo ink fragments were clearly observed on the surface and embedded within glass slides. Surface aggregates were observed as a fine dust and were easily washed off while deeper fragments remained in situ. The embedded fragments were not visible to the unaided eye. Some fragments appeared to have melted yielding an "insect-like" appearance. These were found to be located between approximately 0.2 and 1 mm deep in the glass. Given the particle masses and kinetic energies attained by some of these aggregates their velocities, when leaving the skin, may be hundreds to thousands of metres per second. However, the masses of the aggregates are minuscule meaning that laser operators may be subjected to these high-speed aggregates without their knowledge. These high-speed fragments of ink may pose a contamination risk to laser operators. Lasers Surg. Med. 9999:1-7, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  13. End-pumped Nd:YAG Q-switched laser with high energy and narrow pulse for glass carving

    Science.gov (United States)

    Ling, Ming; Jin, Guang-yong; Tan, Xue-chun; Wu, Zhi-chao; Liang, Zhu

    2009-05-01

    In order to raise the accuracy of glass carving and improve deep cutting, a novel diode end-pumed solid-state laser is researched. Selecting proper volume of laser crytal, one continue wave laser diode which longitudinally pumped Nd:YAG crystal is performed and an applied optics coupling system is designed with self focusing.Computing with ray trace software and MATLAB software, the best parameter is obtained, so pumping beam is coupled efficiently to Nd:YAG.Used a Cr4+:YAG crystal with the singnal transmission of 82% and a line plane-concave cavity, nanosecond narrow pulse is gotten. After two thermal-electrical coolers kept the laser to work at constant temperature instead of water cooling, the volume of laser is markedly reduced. The method of thermal-electrical cooling could increase the system efficiency,achieve the effect of low mode output.Experimental results indicate that the maximum laser output energy in 1064 nm is 118mJ,pulse width is 5 ns, conversion efficiency from light to light is 15.7% under the condition of the incident power of 5 W and the diameter of the output laser spot is less than 1 mm. This end-pumped Nd:YAG Q-switched laser with the light output of high quality and long life, which has 0.01 mm accuracy after lens focusing can satisfy the glass carving with higher precision, rapid speed as well as easy control. It can be used in carving all kinds of glass and replace current CO2 laser.

  14. Ultra-Stable, New Generation Q-Switched Monolithic Laser Cleaners for Fine Art Conservation

    Science.gov (United States)

    Brioschi, F.; Salvadeo, P.

    The increasing use of laser cleaners in fine art conservation boosts the demand on improvements of the laser performances. More power and more wavelengths are required by the current applications, while laser should be more reliable, rugged and compact. The characteristics and performances of a new generation of laser cleaners are presented as a result of a dedicated research and development program.

  15. Computational model of dual q-switching and lasing processes of the pulsed Cr4+:YAG laser pumped by Nd-glass laser

    International Nuclear Information System (INIS)

    Abdul Ghani, B.; Hammadi, M.

    2007-01-01

    A mathematical model describing the absorption and oscillation processes of intracavity Cr 4+ : YAG crystal pumped by Nd-glass laser has been developed, in order to describe the temporal behavior of laser-absorber system. The model has been assumed that the Cr 4+ ions excited to a higher level by excited state absorption, followed by relaxation directly to the upper laser level through fast channel, and indirectly through slow proposed intermediate channel at different lifetimes. The model offers simple kinetic mechanisms for pulsed solid state lasers and also the influence of the variations of the laser input parameters (pumping rate, maximum amplification coefficient and loss coefficient) on the output pulse characteristics of the passive Q-switched Nd-glass and pulsed Cr 4+ : YAG lasers. The model estimates the temporal behavior of the population densities of different levels and laser beam densities as well as predicts the nanosecond output laser pulses of passive Q-switched Nd-glass laser and pulsed Cr 4+ : YAG laser. The calculated results are in good agreement with the available experimental and theoretical data in the literature. (author)

  16. Clinical and histological responses of congenital melanocytic nevi after single treatment with Q-switched lasers

    NARCIS (Netherlands)

    Grevelink, JM; vanLeeuwen, RL; Anderson, RR; Byers, HR

    Background: Laser irradiation of congenital melanocytic nevi is a controversial treatment. Recurrence of lesions after laser treatment appears to be the rule, and the effects of laser irradiation on cellular biological behavior and the possible mutagenic responses of nevomelanocytes that have

  17. Comparison of Q-switched Nd:YAG laser alone versus its combination with ultrapulse CO2 laser for the treatment of black tattoo.

    Science.gov (United States)

    Vanarase, Mithila; Gautam, Ram Krishan; Arora, Pooja; Bajaj, Sonali; Meena, Neha; Khurana, Ananta

    2017-10-01

    Q-switched lasers are conventionally used for the treatment of black tattoo. However, they require multiple sittings, and the response may be slow due to competing epidermal pigment in dark skin. To compare the efficacy of Q-switched Nd:YAG laser alone with its combination with ultrapulse CO 2 for the removal of black tattoo. Sixty patients with black tattoo were randomized into two groups viz., group A and group B. Group A was treated with QS Nd:YAG laser (1064 nm) alone, and group B received combination of ablative ultrapulse CO 2 followed by fixed-dose QS Nd:YAG laser (1064 nm), at 6-week interval for a maximum of 6 sittings. After each sitting, 3 independent physicians noted percentage of improvement that was evaluated using visual analogue scale (VAS) and grading system for tattoo ink lightening (TIL). Combination laser (group B) showed statistically significant improvement in mean VAS score in the last 2 noted visits as compared to 1st session (p tattoos, combination of ultrapulse CO 2 laser and QS Nd:YAG laser is superior to QS Nd:YAG laser alone.

  18. A Q-switched Ho:YAG laser with double anti-misalignment corner cubes pumped by a diode-pumped Tm:YLF laser

    Science.gov (United States)

    Wang, Y. P.; Dai, T. Y.; Wu, J.; Ju, Y. L.; Yao, B. Q.

    2018-06-01

    We report the acousto-optically Q-switched Ho:YAG laser with double anti-misalignment corner cubes pumped by a diode-pumped Tm:YLF laser. In the continuous-wave operation of Ho:YAG laser, the maximum s-polarized output power of 3.2 W at 2090.3 nm was obtained under the absorbed pump power of 12.9 W by rotating the fast axis of quarter-wave plate to change the output transmission of laser cavity. The corresponding optical-to-optical conversion efficiency was 24.8% and the slope efficiency was 55.7%. When one of the corner cubes was rotated to 11.8° around vertical direction or 6.7° around horizontal direction, the laser could still operate stably. For the Q-switched operation, the pulse energy of Ho:YAG laser was 9.9 mJ with a pulse width of 53 ns at the repetition rate of 100 Hz, resulting in a peak power of 186.8 kW. The beam quality factor M2 of Ho:YAG laser was 1.3.

  19. An in-vitro morphological study of Q-switched neodymium/YAG laser trabeculotomy.

    Science.gov (United States)

    Venkatesh, S; Lee, W R; Guthrie, S; Cruickshank, F R; Foulds, W S; Quigley, R J; Bailey, R T

    1986-02-01

    Laser trabeculotomies produced by directing a pulsed neodymium/YAG laser beam at specimens of human anterior chamber angle obtained post mortem or after enucleation were studied by light microscopy and by scanning and transmission electron microscopy to assess the dimensions of the openings created in the trabecular meshwork, their penetrance to the canal of Schlemm, and the extent or absence of laser induced cellular damage in immediately adjacent tissue. A pulse duration of 40-50 ns at energy levels of around 30 mJ was used and the laser cavity carefully tuned to give a Gaussian spatial mode pattern. Openings in the trabecular meshwork typically of 100 microns in diameter and penetrating through to the canal of Schlemm could be regularly created with only minimal damage to adjacent tissue as judged by transmission electron microscopy. The information so gained may be useful in determining the parameters required for successful laser trabeculotomy as a treatment for primary open-angle glaucoma.

  20. Bindi tattoo on forehead: success with modified R-20 technique using low fluence q-switched nd yag laser: a case report.

    Science.gov (United States)

    Zawar, Vijay; Sarda, Aarti; De, Abhishek

    2014-01-01

    Bindi tattoo on the forehead, is one of the cultural practice in Indian women from rural areas. Many patients are not pleased with the appearance of their tattoo and thus seek removal. The development of quality-switched lasers has revolutionized the removal of unwanted tattoos. However, despite multiple treatment sessions, the efficacy is often found to be limited. We herein report a case of green-blue bindi tattoo which failed to clear after 8 sessions of Q-switched Nd YAG laser. The tattoo significantly cleared with R-20 method using low fluence Q-switched Nd YAG Laser. R-20 technique seems to be an effective method of tattoo removal and might be a boon for patients who are reluctant to pursue laser treatment because of fear of expenditure, side effects and uncertainty of result. We report efficacy of R-20 technique for a bindi tattoo on forehead.

  1. Biostimulative effects of Nd:YAG Q-switch dye on normal human fibroblast cultures: study of a new chemosensitizing agent for the Nd:YAG laser

    International Nuclear Information System (INIS)

    Castro, D.J.; Saxton, R.E.; Fetterman, H.R.; Castro, D.J.; Ward, P.H.

    1987-01-01

    Kodak Q-switch II is a new chemical with an absorption maxima at 1051 nm, designed to be used as an Nd:YAG dye laser. The potential for this dye as a new chemosensitizing agent in the treatment of connective tissue diseases and wound healing with low energy Nd:YAG laser was examined. Two normal fibroblast cell lines were tested for sensitivity to various levels of this dye in vitro. These cells were exposed to Q-switch II dye at concentrations of 0.01, 0.1, 1, 10, 50, and 100 micrograms/ml for 1 and 24 hours. Cell viability was assessed by the trypan blue exclusion test. Cell duplication and DNA synthesis were measured by the incorporation of [ 3 H]-thymidine at 6 and 24 hours postexposure to Q-switch II dye. At concentrations up to 10 micrograms/ml, both cell lines tested showed no changes in cell viability. However, at concentrations equal or higher than 50 micrograms/ml, more than 40% of the fibroblasts incorporated trypan blue after 24 hours of exposure to this dye, indicating significant cell destruction. The results indicate that Q-switch II dye is nontoxic to normal human fibroblast cultures and showed significant biostimulative effects on cell duplication at concentrations equal to or lower than 10 micrograms/ml. Further studies will be required to determine the usefulness of Q-switch II dye as a new photochemosensitizing agent for potential biostimulation of wound healing and/or treatment of connective tissue diseases with the Nd:YAG laser (near infrared, 1060 nm) at nonthermal levels of energies

  2. In vitro effect of Q-switched Nd:YAG laser exposure on morphology, hydroxyapatite composition and microhardness properties of human dentin

    Directory of Open Access Journals (Sweden)

    Retna Apsari

    2011-12-01

    Full Text Available Background: A Q-switched Nd:YAG laser was employed as a source of ablation. The fundamental wavelength of the laser is 1064 nm, with pulse duration of 8 nanosecond operates with uniphase mode of TEM00. In the following experiments, dentin samples (without caries and plaque are exposed to pulse laser with Q-switching effect at various energy dose. Purpose: The aim of this study was to investigate the effect of laser ablation on dentin samples using Q-switched Nd:YAG laser exposure. Methods: The laser was operated in repetitive mode with frequency of 10 Hz. The energy dose of the laser was ranging from 13.9 J/cm2, 21.2 J/cm2 and 41.7 J/cm2. The target material comprised of human dentin. The laser was exposed in one mode with Q-switched Nd:YAG laser. Energy delivered to the target through free beam technique. The exposed human dentin was examined by using x-ray diffraction (XRD and fluoresence scanning electron microscopy for energy dispersive (FESEM-EDAX. Microhardness of human dentin were examined by using microhardness vickers test (MVT. Results: The result obtained showed that the composition of hydroxyapatite of the dentin after exposed by Q-switched Nd:YAG laser are 75.02% to 78.21%, with microhardness of 38.7 kgf/mm2 to 86.6 kgf/mm2. This indicated that exposed pulsed Nd:YAG laser on the human dentin attributed to the phototermal effect. The power density created by the Q-switched Nd:YAG laser enables the heat to produce optical breakdown (melting and hole associated with plasma formation and shock wave propagation, from energy dose of 21.2 J/cm2. From XRD analysis showed that the exposure of Nd:YAG laser did not involve in changing the crystal structure of the dentin, but due to photoablation effect. Conclusion: In conclusion, the application of Q-switched Nd:YAG laser as contactless drills in dentistry should be regarded as an alternative to the classical mechanical technique to improve the quality of the dentin treatment.Latar belakang

  3. Efficient in-band diode-pumped Q-switched solid state laser for methane detection, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop an efficient, tunable Q-switched SSL operating at a wavelength of 1651 nm with pulse energy >1 mJ at 2000 Hz repetition rate with in-band...

  4. Sclerosis and the Nd:YAG, Q-switched laser with multiple frequency for treatment of telangiectases, reticular veins, and residual pigmentation.

    Science.gov (United States)

    Cisneros, J L; Del Rio, R; Palou, J

    1998-10-01

    The combination of low concentrations of sclerosing solution and the Nd:YAG, Q-switched laser with multiple (quadruple) frequency provides good results in the treatment of telangiectases and reticular varicose veins of the lower extremities, as well as pigmentation that may appear during sclerotherapy. This paper is based on a series of patients with telangiectases and reticular veins who were treated with sclerotherapy and the Nd:YAG, Q-switched laser with quadruple frequency. Patients with telangiectases and reticular veins received two or three treatment sessions with polydocanol and the Nd:YAG, Q-switched laser with quadruple frequency. Then, they were assessed a clinical score corresponding to the level of improvement achieved. Residual hematic pigmentation lesions were also eliminated with the laser. Excellent improvement was evident in 90% of the patients with minimal residual lesions. The combined technique of sclerosing solution and the Nd:YAG laser with multiple frequency is a valid alternative for the elimination of telangiectases and reticular veins of the lower limbs. This technique has several advantages, such as the use of low concentrations of sclerosing solution, high patient acceptance levels due to minimal disturbances, and the fact that local anesthesia is unnecessary. Good results are obtained without complications and minimal residual pigmentation. These mild pigmentation can be treated with the Nd:YAG laser.

  5. Tunable Q-switched erbium doped fiber laser based on metal transition oxide saturable absorber and refractive index characteristic of multimode interference effects

    Science.gov (United States)

    Mohammed, D. Z.; Khaleel, Wurood Abdulkhaleq; Al-Janabi, A. H.

    2017-12-01

    Ferro-oxide (Fe3O4) nanoparticles were used as a saturable absorber (SA) for a passively Q-switched erbium doped fiber laser (EDFL) with ring cavity. The Q-switching operation was achieved at a pump threshold of 80 mW. The proposed fiber laser produces stable pulses train of repetition rate ranging from 25 kHz to 80 kHz as the pump power increases from threshold to 342 mW. The minimum recorded pulse width was 2.7 μs at 342 mW. The C-band tunability operation was performed using single mode-multimode-single mode fiber (SM-MM-SM) structure. The laser exhibited a total tuning range of 7 nm, maximum sensitivity of 106.9 nm, optical signal to noise ratio (OSNR) of 38 dB and 3-dB linewidth of 0.06 nm.

  6. Passively Q-switched ytterbium- and chromium-doped all-fiber laser

    Czech Academy of Sciences Publication Activity Database

    Dussardier, B.; Maria, J.; Peterka, Pavel

    2011-01-01

    Roč. 50, č. 25 (2011), E20-E23 ISSN 0003-6935 R&D Projects: GA MŠk(CZ) ME10119 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical fiber * fiber lasers * fiber amplifiers Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.703, year: 2010

  7. Generation of nanosecond laser pulses at a 2.2-MHz repetition rate by a cw diode-pumped passively Q-switched Nd3+:YVO4 laser

    International Nuclear Information System (INIS)

    Nghia, Nguyen T; Hao, Nguyen V; Orlovich, Valentin A; Hung, Nguyen D

    2011-01-01

    We report a new configuration of a high-repetition rate nanosecond laser based on a semiconductor saturable absorber mirror (SESAM). The SESAM is conventional technical solution for passive mode-locking at 1064 nm and simultaneously used as a highly reflecting mirror and a saturable absorber in a high-Q and short cavity of a cw diode-end-pumped a-cut Nd 3+ :YVO 4 laser. Two laser beams are coupled out from the cavity using an intracavity low-reflection thin splitter. The laser characteristics are investigated as functions of pump and resonator parameters. Using a 1.8-W cw pump laser diode at 808 nm, the passively Q-switched SESAMbased laser generates 22-ns pulses with an average power of 275 mW at a pulse repetition rate of 2250 kHz.

  8. Mass removal modes in the laser ablation of silicon by a Q-switched diode-pumped solid-state laser (DPSSL)

    International Nuclear Information System (INIS)

    Lim, Daniel J; Ki, Hyungson; Mazumder, Jyoti

    2006-01-01

    A fundamental study on the Q-switched diode-pumped solid-state laser interaction with silicon was performed both experimentally and numerically. Single pulse drilling experiments were conducted on N-type silicon wafers by varying the laser intensity from 10 8 -10 9 W cm -2 to investigate how the mass removal mechanism changes depending on the laser intensity. Hole width and depth were measured and surface morphology was studied using scanning electron microscopy. For the numerical model study, Ki et al's self-consistent continuous-wave laser drilling model (2001 J. Phys. D: Appl. Phys. 34 364-72) was modified to treat the solidification phenomenon between successive laser pulses. The model has the capabilities of simulating major interaction physics, such as melt flow, heat transfer, evaporation, homogeneous boiling, multiple reflections and surface evolution. This study presents some interesting results on how the mass removal mode changes as the laser intensity increases

  9. Retinal hemorrhage thresholds for Q-switched neodymium-Yag laser exposures

    Energy Technology Data Exchange (ETDEWEB)

    Blankenstein, M.F.; Zuclich, J.; Allen, R.G.; Davis, H.; Thomas, S.J.; Harrison, R.F.

    1986-07-01

    Thresholds for retinal vitreal and contained hemorrhages were determined for 1064 nm laser light at 30-nsec and 4-nsec pulsewidths. Rhesus monkeys received graded exposures from a neodymium-yag laser onto either the macular or extramacular region of the retina. Contained hemorrhages appeared as concentric ring structures with white punctate centers. The vitreal hemorrhage was characterized by the presence of choroidal blood in the vitreal chamber at the exposure site. The 30-nsec contained hemorrhage threshold (ED50) was 1.7 mJ on the macula and 2.1 mJ for an extramacular exposure. The 30-nsec vitreal hemorrhage macular threshold was 2.3 mJ, and the extramacular threshold was 6.6 mJ. The threshold for the 4-nsec pulsewidths to produce a hemorrhage (vitreal or contained) on the retina (macula or extramacular) was 340 microJ.

  10. Retinal-hemorrhage thresholds for Q-switched neodymium-YAG laser exposures

    Energy Technology Data Exchange (ETDEWEB)

    Blankenstein, M.F.; Zuclich; Allen, R.G.; Davis; Thomas, S.J.

    1986-07-01

    Thresholds for retinal vitreal and contained hemorrhages were determined for 1064-nm laser light at 30-ns and 4-ns pulsewidths. Rhesus monkeys received graded exposures from a neodymium-YAG laser onto either the macular or extramacular region of the retina. Contained hemorrhages appeared as concentric-ring structures with white punctuate centers. The vitreal hemorrhage was characterized by the presence of choroidal blood in the vitreal chamber at the exposure site. The 30-ns contained-hemorrhage threshold (ED50) was 1.7 mJ on the macula and 2.1 mJ for an extramacular exposure. The 30-ns vitreal-hemorrhage macular threshold was 2.3 mJ, and the extramacular threshold was 6.6 Mj. The threshold for the 4-ns pulse widths to produce a hemorrhage (vitreal or contained) on the retina (macula or extramacular) was 340 uJ.

  11. Q-switch Nd:YAG laser welding of AISI 304 stainless steel foils

    Energy Technology Data Exchange (ETDEWEB)

    P' ng, Danny [Laboratory for Lasers, MEMS and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States); Molian, Pal [Laboratory for Lasers, MEMS and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States)], E-mail: molian@iastate.edu

    2008-07-15

    Conventional fusion welding of stainless steel foils (<100 {mu}m thickness) used in computer disk, precision machinery and medical device applications suffer from excessive distortion, formation of discontinuities (pore, void and hot crack), uncontrolled melting (melt-drop through) and poor aesthetics. In this work, a 15 ns pulsed, 400 mJ Nd:YAG laser beam was utilized to overcome these barriers in seam welding of 60 {mu}m thin foil of AISI 304 stainless steel. Transmission electron microscopy was used to characterize the microstructures while hardness and tensile-shear tests were used to evaluate the strengths. Surface roughness was measured using a DekTak profilometer while porosity content was estimated using the light microscope. Results were compared against the data obtained from resistance seam welding. Laser welding, compared to resistance seam welding, required nearly three times less heat input and produced welds having 50% narrower seam, 15% less porosity, 25% stronger and improved surface aesthetics. In addition, there was no evidence of {delta}-ferrite in laser welds, supporting the absence of hot cracking unlike resistance welding.

  12. Cw and Q-switched Nd:NaLa(MoO4)2 laser noncritical to the temperature drift of the diode pump laser wavelength

    International Nuclear Information System (INIS)

    Ushakov, S N; Lis, Denis A; Subbotin, Kirill A; Romanyuk, V A; Shestakov, A V; Ryabochkina, P A; Shestakova, I A; Zharikov, Evgeny V

    2010-01-01

    Lasing in Nd:NaLa(MoO 4 ) 2 crystals is obtained without stabilisation of the diode pump wavelength. A dependence of the cw laser power (at a wavelength of 1059 nm) on the pump diode temperature is found within a range of 10-458C. It is shown that the variations in the diode temperature within this region change the lasing efficiency no more than by 30%. In the passive Q-switching regime, the experiments were performed under both pulsed and cw pumping. Upon pulsed pumping, the laser energy was 16 μJ at the output pulse duration of 11 ns. The laser wavelength was 1059 nm, as well as in the case of cw operation. Upon cw pumping with a power of 1.5 W, laser pulses were obtained with an energy of 15 μJ. (lasers)

  13. Dual-wavelength mid-infrared CW and Q-switched laser in diode end-pumped Tm,Ho:GdYTaO4 crystal

    Science.gov (United States)

    Wang, Beibei; Gao, Congcong; Dou, Renqin; Nie, Hongkun; Sun, Guihua; Liu, Wenpeng; Yu, Haijuan; Wang, Guoju; Zhang, Qingli; Lin, Xuechun; He, Jingliang; Wang, Wenjun; Zhang, Bingyuan

    2018-02-01

    Dual-wavelength continuous-wave and Q-switched lasers are demonstrated in a Tm,Ho:GdYTaO4 crystal under 790 nm laser diode end pumping for the first time to the best of our knowledge. The laser operates with a dual wavelength at 1949.677 nm and 2070 nm for continuous-wave with a spacing of about 120 nm. The maximum output power is 0.332 W with a pump power of 3 W. By using graphene as the saturable absorber, a passively Q-switched operation is performed with a dual-wavelength at 1950.323 nm and 2068.064 nm with a wavelength interval of about 118 nm. The maximum average output power of the Q-switched laser goes up to 200 mW with a minimum pulse duration of 1.2 µs and a maximum repetition rate of 34.72 kHz.

  14. Tunable continuous wave and passively Q-switched Nd:LuLiF4 laser with monolayer graphene as saturable absorber

    International Nuclear Information System (INIS)

    Wang, Feng; Luo, Jianjun; Li, Shixia; Li, Tao; Li, Ming

    2015-01-01

    Tunable continuous wave and passively Q-switched Nd:LuLiF 4 laser performances were demonstrated. Employing a 2 mm thick quartz plate as the birefringence filter, three continuous tuning ranges from 1045.2 to 1049.9 nm, 1051 to 1055.1 nm and 1072.1 to 1074.3 nm could be obtained. Q-switched laser operation was realized by using a monolayer graphene as a saturable absorber. At an incident pump power of 5.94 W, the maximum average output power was 669 mW with the pulse duration of 210 ns and the pulse repetition rate of 145 kHz at T = 10%. (paper)

  15. Effects of tattoo ink's absorption spectra and particle size on cosmetic tattoo treatment efficacy using Q-switched Nd:YAG laser.

    Science.gov (United States)

    Leu, Fur-Jiang; Huang, Chuen-Lin; Sue, Yuh-Mou; Lee, Shao-Chen; Wang, Chia-Chen

    2015-01-01

    The mechanisms responsible for variable responses of cosmetic tattoos to Q-switched laser removal treatment remain unclear. We sought to investigate the properties of tattoo inks that may affect the efficacy of laser-assisted tattoo removal. The absorption of white, brown, and black inks before and after Q-switched neodymium-doped yttrium aluminum garnet laser irradiation were analyzed by a reflectance measurement system. Rats were tattooed using the three inks and treated with the same laser for two sessions. Skin biopsies were taken from the treated and untreated sites. Black ink showed strong absorption, reduced after laser irradiation, over the entire spectrum. White ink had low absorption over the visible light spectrum, and brown ink had strong absorption at 400-550 nm wavelengths. White and brown inks turned dark after laser exposure, and the absorption of laser-darkened inks were intermediate between their original color and black ink. White, brown, and black tattoos in rat skin achieved poor, fair to good, and excellent responses to laser treatment, respectively. Transmission electron microscopy showed that white tattoo particles were the largest, brown were intermediate, and black were the smallest before laser. After laser treatment, white and brown tattoo particles were mixtures of large and small particles, while black particles showed overall reduction in number and size. Black tattoo ink's excellent response to Q-switched lasers was associated with its strong absorption and small particle size. White tattoo ink's poor response was associated with its poor absorption, even after laser darkening, and large particle size.

  16. Resonant photoacoustic detection of NO2 traces with a Q-switched green laser

    Science.gov (United States)

    Slezak, Verónica; Codnia, Jorge; Peuriot, Alejandro L.; Santiago, Guillermo

    2003-01-01

    Resonant photoacoustic detection of NO2 traces by means of a high repetition pulsed green laser is presented. The resonator is a cylindrical Pyrex glass cell with a measured Q factor 380 for the first radial mode in air at atmospheric pressure. The system is calibrated with known mixtures in dry air and a minimum detectable volume concentration of 50 parts in 109 is obtained (S/N=1). Its sensitivity allows one to detect and quantify NO2 traces in the exhaust gases of cars. Previously, the analysis of gas adsorption and desorption on the walls and of changes in the sample composition is carried out in order to minimize errors in the determination of NO2 content upon application of the extractive method. The efficiency of catalytic converters of several models of automobiles is studied and the NO2 concentration in samples from exhausts of different types of engine (gasoline, diesel, and methane gas) at idling operation are measured.

  17. Solitary pulse-on-demand production by optical injection locking of passively Q-switched InGaN diode laser near lasing threshold

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, X., E-mail: xi.zeng@csem.ch, E-mail: dmitri.boiko@csem.ch; Stadelmann, T.; Grossmann, S.; Hoogerwerf, A. C.; Boïko, D. L., E-mail: xi.zeng@csem.ch, E-mail: dmitri.boiko@csem.ch [Centre Suisse d' Electronique et de Microtechnique SA (CSEM), CH-2002 Neuchâtel (Switzerland); Sulmoni, L.; Lamy, J.-M.; Grandjean, N. [Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

    2015-02-16

    In this letter, we investigate the behavior of a Q-switched InGaN multi-section laser diode (MSLD) under optical injection from a continuous wave external cavity diode laser. We obtain solitary optical pulse generation when the slave MSLD is driven near free running threshold, and the peak output power is significantly enhanced with respect to free running configuration. When the slave laser is driven well above threshold, optical injection reduces the peak power. Using standard semiconductor laser rate equation model, we find that both power enhancement and suppression effects are the result of partial bleaching of the saturable absorber by externally injected photons.

  18. Complete resolution of minocycline pigmentation following a single treatment with non-ablative 1550-nm fractional resurfacing in combination with the 755-nm Q-switched alexandrite laser.

    Science.gov (United States)

    Vangipuram, Ramya K; DeLozier, Whitney L; Geddes, Elizabeth; Friedman, Paul M

    2016-03-01

    Pigmentation secondary to minocycline ingestion is an uncommon adverse event affecting 3.7-14.8% of treated individuals for which few effective therapies are available. Three patterns of minocycline pigmentation have a characteristic clinical and histological appearance. The pigment composition in each variety is different and occurs at varying skin depths. Accordingly, a tailored approach according to the type of minocycline pigmentation is crucial for treatment success. The purpose of this intervention was to evaluate the efficacy of non-ablative fractional photothermolysis in combination with the Q-switched alexandrite laser for the treatment of type I minocycline pigmentation on the face. A patient with type I minocycline pigmentation was treated with non-ablative 1550-nm fractional photothermolysis followed immediately by 755-nm Q-switched alexandrite laser and then observed clinically to determine the outcome of this modality. The patient was seen in clinic 1 month later following her single treatment session and 100% clearance of all blue facial pigment was observed. Non-ablative fractional photothermolysis in combination with the 755-nm Q-switched alexandrite laser should be considered for treatment of type I minocycline pigmentation. © 2015 Wiley Periodicals, Inc.

  19. Mo0.5W0.5S2 for Q-switched pulse generation in ytterbium-doped fiber laser

    Science.gov (United States)

    Wang, Junli; Chen, Lei; Dou, Chenxi; Yan, Haiting; Meng, Lingjie; Wei, Zhiyi

    2018-06-01

    In this work, we fabricate the Mo0.5W0.5S2 by microwave-assisted solvothermal method, and report the Q-switched Yb-doped fiber lasers (YDFL) using Mo0.5W0.5S2 polymer film and tapered fiber as the saturable absorbers (SAs). The modulation depth and saturable intensity of the film SA are 5.63% and 6.82 MW cm‑2. The shortest pulse duration and the maximum single pulse energy are 1.22 μs and 148.8 nJ for the film SA, 1.46 μs and 339 nJ for the fiber-taper SA. To the best of our knowledge, this is the first report on the Q-switched YDFL using Mo0.5W0.5S2 SAs.

  20. Passively Q-switched dual-wavelength thulium-doped fiber laser based on a multimode interference filter and a semiconductor saturable absorber

    Science.gov (United States)

    Wang, M.; Huang, Y. J.; Ruan, S. C.

    2018-04-01

    In this paper, we have demonstrated a theta cavity passively Q-switched dual-wavelength fiber laser based on a multimode interference filter and a semiconductor saturable absorber. Relying on the properties of the fiber theta cavity, the laser can operate unidirectionally without an optical isolator. A semiconductor saturable absorber played the role of passive Q-switch while a section of single-mode-multimode-single-mode fiber structure served as an multimode interference filter and was used for selecting the lasing wavelengths. By suitably manipulating the polarization controller, stable dual-wavelength Q-switched operation was obtained at ~1946.8 nm and ~1983.8 nm with maximum output power and minimum pulse duration of ~47 mW and ~762.5 ns, respectively. The pulse repetition rate can be tuned from ~20.2 kHz to ~79.7 kHz by increasing the pump power from ~2.12 W to ~5.4 W.

  1. Mid-infrared Fe2+:ZnSe semiconductor saturable absorber mirror for passively Q-switched Er3+-doped ZBLAN fiber laser

    Directory of Open Access Journals (Sweden)

    Shougui Ning

    2018-02-01

    Full Text Available A mid-infrared (mid-IR semiconductor saturable absorber mirror (SESAM based on Fe2+:ZnSe for passively Q-switched Er3+-doped ZBLAN fiber laser has been demonstrated. Fe2+:ZnSe SESAM was fabricated by electron beam evaporation method. Fe2+ was innovatively doped into the reflective Bragg stack, in which ZnSe layer served as both doped matrix and high refractive layer during the fabricating process. By using the Fe2+:ZnSe SESAM, stable passively Q-switched pulses with the minimum pulse width of 0.43 μs under a repetition rate of 160.82 kHz were obtained. The recorded maximum average output power of 873 mW with a peak power of 12.59 W and pulse energy of 5.43 μJ were achieved. The results demonstrated a new method for fabricating Fe2+:ZnSe SESAM, which can be used in compact mid-IR Q-switched fiber laser.

  2. Characterisation of the light pulses of a cavity dumped dye laser pumped by a cw mode-locked and q-switched Nd:YAG laser

    International Nuclear Information System (INIS)

    Geist, P.; Heisel, F.; Martz, A.; Miehe, J.A.; Miller, R.J.D.

    1984-01-01

    The frequency doubled pulses (of 532 nm) obtained, with the help of a KTP crystal, from those delivered by either a continuous wave mode-locked (100 MHz) or mode-locked Q-switched (0-1 KHz) Nd: YAG laser, are analyzed by means of a streak camera, operating in synchroscan or triggered mode. In the step-by-step measurements the pulse stability, concerning form and amplitude, is shown. In addition, measurements effectuated with synchronously pumped and cavity dumped dye laser (Rhodamine 6G), controlled by a Pockels cell, allows the obtention of stable and reproducible single pulses of 30 ps duration, 10 μJ energy and 500Hz frequency [fr

  3. Simulation of laser-tattoo pigment interaction in a tissue-mimicking phantom using Q-switched and long-pulsed lasers.

    Science.gov (United States)

    Ahn, K J; Kim, B J; Cho, S B

    2017-08-01

    Laser therapy is the treatment of choice in tattoo removal. However, the precise mechanisms of laser-tattoo pigment interactions remain to be evaluated. We evaluated the geometric patterns of laser-tattoo pigment particle interactions using a tattoo pigment-embedded tissue-mimicking (TM) phantom. 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. Most of the laser-tattoo interactions in the experimental conditions formed cocoon-shaped or oval photothermal and photoacoustic injury zones, which contained fragmented tattoo particles in various sizes depending on the conditions. In addition, a long-pulsed 755-nm alexandrite laser was used at a spot size of 6 mm and pulse widths of 3, 5, and 10 ms. The finer granular pattern of tattoo destruction was observed in TM phantoms treated with 3- and 5-ms pulse durations compared to those treated with a 10-ms pulse. We outlined various patterns of laser-tattoo pigment interactions in a tattoo-embedded TM phantom to predict macroscopic tattoo and surrounding tissue reactions after laser treatment for tattoo removal. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Tattoo removal in micropigs with low-energy pulses from a Q-switched Nd:YAG laser at 1064 nm

    Science.gov (United States)

    Hu, Xin-Hua; Wooden, W. A.; Cariveau, Mickael J.; Fang, Qiyin; Bradfield, J. F.; Kalmus, Gerhard W.; Vore, S. J.; Sun, Y.

    2001-05-01

    Treatment of pigmented lesions in skin with visible or near- infrared nanosecond (ns) laser pulses often causes significant collateral tissue damage because the current approach uses pulses with energy of 300 mJ or larger. Additionally, this requires large Q-switched laser systems. To overcome these disadvantages, we have investigated a different approach in delivering ns laser pulses for cutaneous lesion treatment. Tattoo removal in an animal model with a focused laser beam from a Q-switched Nd:YAG laser has been investigated in two Yucatan micropigs tattooed with blue, black, green and red pigments. The tattoos were treated with a focused beam of 12-ns pulses at 1064 nm, with different depth under the skin surface, while the micropig was translated to achieve an effect of single pulse per ablation site in the skin. With the pulse energy reduced to a range from 38 to 63 mJ, we found that nearly complete clearance was achieved for blue and black tattoos while clearance of red and green tattoos was incomplete. Analysis of the skin appearance suggested that the pulse energy can be decreased to below 20 mJ which may lead to further reduction of the collateral tissue damage and improve the clearance of red and green tattoos.

  5. Effect of laser beam conditioning on fabrication of clean micro-channel on stainless steel 316L using second harmonic of Q-switched Nd:YAG laser

    Science.gov (United States)

    Singh, Sanasam Sunderlal; Baruah, Prahlad Kr; Khare, Alika; Joshi, Shrikrishna N.

    2018-02-01

    Laser micromachining of metals for fabrication of micro-channels generate ridge formation along the edges accompanied by ripples along the channel bed. The ridge formation is due to the formation of interference pattern formed by back reflections from the beam splitter and other optical components involved before focusing on the work piece. This problem can be curtailed by using a suitable aperture or Iris diaphragm so as to cut the unwanted portion of the laser beam before illuminating the sample. This paper reports an experimental investigation on minimizing this problem by conditioning the laser beam using an Iris diaphragm and using optimum process parameters. In this work, systematic experiments have been carried out using the second harmonic of a Q-switched Nd:YAG laser to fabricate micro-channels. Initial experiments revealed that formation of ridges along the sides of micro-channel can easily be minimized with the help of Iris diaphragm. Further it is noted that a clean micro-channel of depth 43.39 μm, width up to 64.49 μm and of good surface quality with average surface roughness (Ra) value of 370 nm can be machined on stainless steel (SS) 316L by employing optimum process condition: laser beam energy of 30 mJ/pulse, 11 number of laser scans and scan speed of 169.54 μm/s with an opening of 4 mm diameter of Iris diaphragm in the path of the laser beam.

  6. Study on the pathogenesis of transient intraocular pressure after laser iridectomy with Krypton laser combined with Q-switched Nd:YAG laser

    Directory of Open Access Journals (Sweden)

    Zhi-Juan Pei

    2017-12-01

    Full Text Available AIM: To study the pathogenesis of transient intraocular pressure(IOPafter laser iridectomy with Krypton laser combined with Q-switched Nd:YAG laser. METHODS: Totally 42 healthy rabbits(84 eyesprovided by the Animal Experimental Center of our hospital were selected, including 18 female rabbits, 24 male rabbits, average weight 2.24±0.31kg, and they were randomly divided into 6 groups, 7 rats in each group(14 eyes. We observed the change of intraocular pressure after laser iridectomy surgery at 20min, 2, 6, 18, 24h and the nitric oxide(NO, malondialdehyde(MDA, superoxide dismutase(SOD, 6-keto-prostaglandin(6-keto-PGF1αand nitric oxide synthase(NOScontent in aqueous. RESULTS: There was no significant difference in intraocular pressure, NO, NOS, SOD, MAD and 6-keto- PGF1α before operation(P>0.05. The intraocular pressure increased after operation, and the difference was statistically significant(PP>0.05. The levels of NO, NOS and SOD in the aqueous humor of the two groups decreased 20min, 2 and 6h after the operation(PP>0.05. The levels of MDA and 6-keto-prostaglandin in the aqueous humor increased after the operation, and the difference was statistically significant at 20min, 2 and 6h after operation(PP>0.05.CONCLUSION: The increase of transient intraocular pressure after laser iridectomy may relate to the increase of malondialdehyde, 6-keto-prostaglandin content and the decrease of superoxide dismutase and nitric oxide in the aqueous humor after operation.

  7. Potential role of S100A8 in skin rejuvenation with the 1064-nm Q-switched Nd:YAG laser.

    Science.gov (United States)

    Qin, Yan; Qin, Xiaofeng; Xu, Peng; Zhi, Yuanting; Xia, Weili; Dang, Yongyan; Gu, Jun; Ye, Xiyun

    2018-04-01

    The 1064-nm Q-switched Nd:YAG laser is demonstrated to be effective for non-ablative skin rejuvenation, but the molecular mechanism by which dermis responses to laser-induced damage and initiates skin remodeling is still unclear. HaCaT cells and 3T3 skin fibroblasts were irradiated with the 1064-nm Q-switched Nd:YAG laser at the different doses. Then, cells were collected and lysed for PCR and Western blot analysis. Cell viability was detected by Cell Counting Kit-8 (CCK-8) before and after laser irradiation. The expressions of S100A8, advanced glycosylation end product-specific receptor (RAGE) and inflammatory cytokines in two cell lines were markedly upregulated after laser treatments. The PCR, Western blot, and ELISA analysis showed the significant increase of type I and III procollagen in the 3T3 cells treated with the 1064-nm laser. Interestingly, si S100A8 effectively inhibited the expression of cytokines and collagen, while S100A8 treatments significantly increased them. P-p38 and p-p65 levels were also elevated after the 1064-nm laser irradiation, which is positively related with S100A8. Cell viability and reactive oxygen species (ROS) levels were not changed, while the content of superoxidase dismutase (SOD) in two cells was increased after laser irradiation. Our results demonstrated that the overexpression of S100A8 induced by the 1064-nm laser irradiation triggered inflammatory reactions in skin cells. The inflammatory microenvironment and improvement of skin antioxidant capacity contribute to new collagen synthesis in the skin cells. Thus, S100A8 was required for laser-induced new collagen synthesis in skin cells. p38/MAPK and NF-κB signal pathways were involved in S100A8-mediated inflammatory reactions in response to laser irradiation.

  8. CW and AO Q-switched operation of a dual-crystal Tm, Ho:GdVO4 laser pumped by two diodes

    International Nuclear Information System (INIS)

    Li, L J; Bai, Y F; Liu, Y W; He, Z L; Wang, J; Yao, B Q; Zhou, S; Xing, M N

    2013-01-01

    Continuous wave (CW) mode and acousto-optic (AO) Q-switched mode operation of a dual-crystal Tm, Ho:GdVO 4 laser is reported. The dual-crystal Tm, Ho:GdVO 4 laser with output wavelength of 2.05 μm was pumped by two laser diodes (LDs). The Tm, Ho:GdVO 4 crystals were cooled by liquid nitrogen and pumped by two fiber-coupled LDs with a center output wavelength of 801.0 nm. A 20.5 W output power was obtained at a 255 mm physical cavity length in CW mode operation, and a 19.6 W average power was obtained at a pulse repetition frequency (PRF) of 10 kHz with a 19 ns pulse duration. Also, the efficiency loss of the laser is not more than 4.4% from CW mode to Q-switch mode, and the M 2 factor, which is measured by the traveling knife-edge method, does not exceed 1.2. (paper)

  9. Diode-Pumped Quasi-Three-Level Passively Q-Switched Nd:GGG Laser with a Codoped Nd,Cr:YAG Saturable Absorber

    International Nuclear Information System (INIS)

    Kun-Na, He; Chun-Qing, Gao; Zhi-Yi, Wei; Qi-Nan, Li; Zhi-Guo, Zhang; Hai-He, Jiang; Shao-Tang, Yin; Qing-Li, Zhang

    2009-01-01

    We demonstrate the first quasi-three-level passively Q-switched Nd:GGG laser at 937 nm using a Nd,Cr:YAG crystal as the saturable absorber. The dependences of the average output power, the repetition rate and the pulse width on the incident pump power are obtained. A maximum average output power of 1.18 W with repetition rate of 35 kHz and pulse width of 45 ns is achieved at an incident pump power of 18.3 W. The corresponding optical-to-optical and slope efficiencies are 6% and 10%, respectively

  10. Study of simultaneous q-switching and mode-locking in ND:YVO4 laser with Cr4+:YAG crystal

    International Nuclear Information System (INIS)

    Al-Sous, M. B.

    2009-01-01

    A numerical model of rate equations for a four-level solid-state laser with Cr 4+ :YAG saturable absorber including excited state absorption ESA is presented. The cavity is divided into a large number of disks and the model is solved for each disk and its local corresponding photon flux. The flux array is shifted for each recurrence simulating the movement of photons inside the cavity during the round trip. This simulator can describe the mode locking phenomenon and can be used to simulate the simultaneous mode locking and Q-switching with a saturable absorber. (author)

  11. Short-Pulse-Width Repetitively Q-Switched ~2.7-μm Er:Y2O3 Ceramic Laser

    Directory of Open Access Journals (Sweden)

    Xiaojing Ren

    2017-11-01

    Full Text Available A short-pulse-width repetitively Q-switched 2.7-μm Er:Y2O3 ceramic laser is demonstrated using a specially designed mechanical switch, a metal plate carved with slits of both slit-width and duty-cycle optimized. With a 20% transmission output coupler, stable pulse trains with durations (full-width at half-maximum, FWHM of 27–38 ns were generated with a repetition rate within the range of 0.26–4 kHz. The peak power at a 0.26 kHz repetition rate was ~3 kW.

  12. Study of simulations q-switching and mode-locking in Nd:YVO4 laser with Cr4+:YAG crystal

    International Nuclear Information System (INIS)

    Al-Sous, M. B.

    2007-12-01

    A numerical model of rate equations for a four-level solid-state laser with Cr 4+ :YAG saturable absorber including excited state absorption ESA is presented. The cavity is divided into a large number of disks and the model is solved for each disk and its local corresponding photon flux. The flux array is shifted for each recurrence simulating the movement of photons inside the cavity during the round trip. This simulator can describe the mode locking phenomenon and can be used to simulate the simultaneous mode locking and Q-switching with a saturable absorber.(author)

  13. The study of 670.7 nm red light generated by intracavity frequency doubling of a Q-switched Nd : YAlO3 laser

    International Nuclear Information System (INIS)

    Zhu Haiyong; Zhang Ge; Huang Chenghui; Wei Yong; Huang Lingxiong; Huang Yidong

    2009-01-01

    High-power 670.7 nm red light was obtained by intracavity frequency doubling of a Q-switched Nd : YAlO 3 (Nd : YAP) laser with a critical phase matching (θ = 85.9 0 , φ = 0 0 ) cut LBO. Experimental configurations using V-cavity and Z-cavity have been adopted for comparison. The highest output power of 19.7 W was achieved in the Z-cavity with optical-optical efficiency of 4%. Compared with the laser using an Nd : YAG crystal, the adoption of Nd : YAP simplified the laser system in the absence of a solid etalon and the Brewster plate. The output power stability of the red laser was investigated and the fluctuation was lower than 3% at the output power of 18 W an hour.

  14. Observation of Q-switching and mode-locking in two-section InAs/InP (100) quantum dot lasers around 1.55 mum.

    Science.gov (United States)

    Heck, Martijn J R; Bente, Erwin A J M; Smalbrugge, Barry; Oei, Yok-Siang; Smit, Meint K; Anantathanasarn, Sanguan; Nötzel, Richard

    2007-12-10

    First observation of passive mode-locking in two-section quantum-dot lasers operating at wavelengths around 1.55 mum is reported. Pulse generation at 4.6 GHz from a 9 mm long device is verified by background-free autocorrelation, RF-spectra and real-time oscilloscope traces. The output pulses are stretched in time and heavily up-chirped with a value of 20 ps/nm, contrary to what is normally observed in passively mode-locked semiconductor lasers. The complete output spectrum is shown to be coherent over 10 nm. From a 7 mm long device Q-switching is observed over a large operating regime. The lasers have been realized using a fabrication technology that is compatible with further photonic integration. This makes the laser a promising candidate for e.g. a mode-comb generator in a complex photonic chip.

  15. Spectral and power characteristics of a 5% Tm : KLu(WO4)2 Nm-cut minislab laser passively Q-switched by a Cr2+ : ZnSe crystal

    Science.gov (United States)

    Vatnik, S. M.; Vedin, I. A.; Kurbatov, P. F.; Smolina, E. A.; Pavlyuk, A. A.; Korostelin, Yu. V.; Skasyrsky, Ya. K.

    2017-12-01

    Laser characteristics of a 5%Tm : KLu(WO4)2 Nm-cut minislab laser passively Q-switched by a Cr2+ : ZnSe saturable absorber are presented. At a pump power of 21 W, the average laser power at a wavelength of 1.91 μm was 3.2 W (pulse duration 35 ns, pulse energy 0.3 mJ). The maximum slope efficiency of the laser in the Q-switched regime was 31%; the loss in power with respect to the cw regime did not exceed 17%. At pump powers above 15 W, the dependence of the output power in the Q-switched regime on the pump power considerably differed from linear, which was explained by the formation of a thermal lens in the saturable absorber volume. The experimental energies and durations of laser pulses well agree with the values calculated from rate equations.

  16. Effect of spot size and fluence on Q-switched alexandrite laser treatment for pigmentation in Asians: a randomized, double-blinded, split-face comparative trial.

    Science.gov (United States)

    Wang, Chia-Chen; Chen, Chih-Kang

    2012-10-01

    Q-switched laser treatment for pigment disorders commonly leads to postinflammatory hyperpigmentation (PIH) in Asians. To evaluate the effect of spot size and fluence on Q-switched alexandrite laser (QSAL) treatment for pigmentation in Asians. Ten patients with freckles, 18 with lentigines, and 8 with acquired bilateral nevus of Ota-like macules (ABNOM) received 1 session of QSAL treatment for a 3-mm spot on one cheek and a 4-mm spot on the other cheek. The lowest fluences to achieve a visible biologic effect were chosen. The patients with freckles experienced the highest improvement rate (83-84%), followed by those with lentigines (52%) and ABNOM (35%). Similar efficacy was observed for both cheeks (p > 0.05). PIH developed in 10% (1/10), 44% (8/18), and 75% (6/8) of the patients with freckles, lentigines, and ABNOM, respectively. The severity of PIH was lower in the 4-mm spot with a lower fluence than in the 3-mm spot with a higher fluence in patients with lentigines (p = 0.03), but not in those with freckles or ABNOM. Using a larger spot to achieve the same biologic effect at a lower fluence is associated with equal efficacy and less-severe PIH in patients with lentigines.

  17. Diode-pumped continuous-wave and passively Q-switched 1066 nm Nd:GYNbO4 laser

    Science.gov (United States)

    Ma, Yufei; Peng, Zhenfang; He, Ying; Li, Xudong; Yan, Renpeng; Yu, Xin; Zhang, Qingli; Ding, Shoujun; Sun, Dunlu

    2017-08-01

    A diode-pumped passively Q-switched 1066 nm laser with a novel Nd:Gd0.69Y0.3NbO4 mixed crystal was demonstrated for the first time to the best of our knowledge. In the continuous-wave (CW) operation, optimization selection of output couplers was carried out, and a maximum output power of 2.13 W was obtained when the plane mirror with transmission of 25% was chosen and the absorbed pump power was 10.5 W. The Cr4+:YAG passively Q-switched Nd:Gd0.69Y0.3NbO4 laser performance was investigated. At an absorbed pump power of 10.5 W, using Cr4+:YAG with initial transmission of 80%, the obtained minimum pulse width was 7.2 ns with the pulse repetition rate of 19 kHz. The single pulse energy and peak power were estimated to be 26.7 µJ and 3.7 kW, respectively.

  18. Black phosphorus saturable absorber for a diode-pumped passively Q-switched Er:CaF2 mid-infrared laser

    Science.gov (United States)

    Li, Chun; Liu, Jie; Guo, Zhinan; Zhang, Han; Ma, Weiwei; Wang, Jingya; Xu, Xiaodong; Su, Liangbi

    2018-01-01

    A multilayer black phosphorus, as a novel two dimensional saturable absorber, has superb saturable absorption properties for a Er:CaF2 solid-state pulse laser. The pulse laser is realized at mid-infrared region with the passively Q-switched technology by a diode-pumping. The high-quality black phosphorus saturable absorber is fabricated by liquid phase exfoliation method. The pulse laser generates the pulses operation with the pulse duration of 954.8 ns, the repetition rate of 41.93 kHz, the pulse energy of 4.25 μJ and the peak power of 4.45 W. Our work demonstrates that black phosphorus could be used as a kind of efficient mid-infrared region optical absorber for ultrafast photonics.

  19. An All-Fiber Gas Raman Light Source Based on a Hydrogen-Filled Hollow-Core Photonic Crystal Fiber Pumped with a Q-Switched Fiber Laser

    International Nuclear Information System (INIS)

    Chen Xiao-Dong; Mao Qing-He; Sun Qing; Zhao Jia-Sheng; Li Pan; Feng Su-Juan

    2011-01-01

    A gas Raman light source based on a H 2 -filled hollow-core photonic-crystal-fiber cell with a Q-switched fiber laser followed by a fiber amplifier as the Raman pump source is demonstrated. The Stokes frequency-shift lasing line is observed at 1135.7 nm with the Q-switched pump pulses at 1064.7 nm. Our experimental results show that the generated Stokes pulse is much narrower than the pump pulse, and the generated Stokes pulse duration is increased with the single pulse energy for the same duration pump pulses. For the 125 ns pump pulses with a repetition rate of 5 kHz, the Raman threshold pump energy and the conversion efficiency at the Raman threshold are 2.13 μJ and 9.82%. Moreover, by choosing narrower pump pulses, the Raman threshold pump energy may be reduced and the conversion efficiency may be improved. (fundamental areas of phenomenology(including applications))

  20. Continuous wave and AO Q-switch operation Tm,Ho:YAP laser pumped by a laser diode of 798 nm

    International Nuclear Information System (INIS)

    Li, L J; Yao, B Q; Song, C W; Wang, Y Z; Wang, Z G

    2009-01-01

    Continuous wave (CW) and acousto-optical (AO) Q-switch operation of Tm (5 at.%), Ho (0.3 at.%):YAP laser at 2.13 μm wavelength were reported in this paper. The Tm,Ho:YAP crystal was cooled by liquid nitrogen and double-end-pumped by a 14.2 W fiber-coupled laser diode at 798 nm. Different resonator lengths and output couplers for the pump power were tried. A maximum conversion efficiency of 31.3% and a maximum slope efficiency of 35.2% were acquired with CW output power of 4.45 W. Average power of 4.21 W was obtained at pulse repetition frequency (PRF) of 15 kHz, corresponding to an optical-to-optical conversion efficiency of 29.6% and a slope efficiency of 32.4%. The energy per pulse of 2.3 mJ in 64 ns was achieved at 1.5 kHz with the peak power of 35.8 kW

  1. Successful treatment of tattoo-induced pseudolymphoma with sequential ablative fractional resurfacing followed by Q-switched Nd: Yag 532 nm laser

    Directory of Open Access Journals (Sweden)

    Tan Siyun Lucinda

    2013-01-01

    Full Text Available Decorative tattooing has been linked with a range of complications, with pseudolymphoma being unusual and challenging to manage. We report a case of tattoo-induced pseudolymphoma, who failed treatment with potent topical and intralesional steroids. She responded well to sequential treatment with ablative fractional resurfacing (AFR followed by Q-Switched (QS Nd:YAG 532 nm laser. Interestingly, we managed to document the clearance of her tattoo pigments after laser treatments on histology and would like to highlight the use of special stains such as the Grocott′s Methenamine Silver (GMS stain as a useful method to assess the presence of tattoo pigment in cases where dense inflammatory infiltrates are present.

  2. Continuous-wave and acousto-optically Q-switched 1066 nm laser performance of a novel Nd:GdTaO4 crystal

    Science.gov (United States)

    Ma, Yufei; He, Ying; Peng, Zhenfang; Sun, Haiyue; Peng, Fang; Yan, Renpeng; Li, Xudong; Yu, Xin; Zhang, Qingli; Ding, Shoujun

    2018-05-01

    A diode-pumped acousto-optically (AO) Q-switched 1066 nm laser with a novel Nd:GdTaO4 crystal was demonstrated for the first time to the best of our knowledge. The optimization selection of output coupler was carried out in the continuous-wave (CW) operation. After that the pulsed Nd:GdTaO4 laser performances using different modulation repetition rates of 10 kHz and 20 kHz were investigated. At an absorbed pump power of 10 W and repetition rates of 10 kHz, the obtained minimum pulse width was 28 ns and the maximum peak power was 5.4 kW.

  3. Successful Treatment of Tattoo-Induced Pseudolymphoma with Sequential Ablative Fractional Resurfacing Followed by Q-Switched Nd: YAG 532 nm Laser

    Science.gov (United States)

    Lucinda, Tan Siyun; Hazel, Oon Hwee Boon; Joyce, Lee Siong Siong; Hon, Chua Sze

    2013-01-01

    Decorative tattooing has been linked with a range of complications, with pseudolymphoma being unusual and challenging to manage. We report a case of tattoo-induced pseudolymphoma, who failed treatment with potent topical and intralesional steroids. She responded well to sequential treatment with ablative fractional resurfacing (AFR) followed by Q-Switched (QS) Nd:YAG 532 nm laser. Interestingly, we managed to document the clearance of her tattoo pigments after laser treatments on histology and would like to highlight the use of special stains such as the Grocott's Methenamine Silver (GMS) stain as a useful method to assess the presence of tattoo pigment in cases where dense inflammatory infiltrates are present. PMID:24470721

  4. Efficacy of the Q-switched Neodymium: Yttrium Aluminum Garnet Laser in the Treatment of Blue-black Amateur and Professional Tattoos.

    Science.gov (United States)

    Lakshmi, Chembolli; Krishnaswamy, Gayathri

    2015-01-01

    Q-switched neodymium: yttrium aluminum garnet (Nd: YAG) laser at a wavelength of 1064 nm primarily targets dermal melanin and black tattoo ink. Recent studies have shown that this laser is effective in treating black tattoos. There are few studies conducted in India for the same. The aim was to assess the effectiveness of Q-switched Nd: YAG laser (QSNYL) in the treatment of blue-black tattoos following 3 treatment sessions. This study, a prospective interventional study included a total of 12 blue-black tattoos. Following informed consent for the procedure, as well as for photographs, a questionnaire was administered, and improvement perceived by the patient was recorded. In addition, global assessment score (GAS) by a blinded physician was also recorded. Photographs were taken at baseline and at every follow-up. Each patient underwent three treatment sessions with 1064 nm QSNYL at 4-6 weekly intervals. Fluences ranged from 1.8 to 9 J/cm(2). The follow-up was done monthly for 4 months from the first treatment session. The response was assessed by patient assessment (PA) and GAS by comparing photographs. After three treatment sessions, although no patient achieved clearance, most patients showed good response with few adverse effects. An average of 64.1% (GAS) and 54.2% (PA) improvement was observed in 12 tattoos. Tattoos more than 10-year-old showed quicker clearing than those less than 10-year-old. Amateur tattoos also showed a better response in comparison to professional tattoos. Totally, 1064 nm QSNYL is safe and effective for lightening blue-black tattoos in pigmented Indian skin. All patients achieved near complete clearance following the continuation of treatment (an average of six sessions) although this was spaced at longer intervals.

  5. Rapid, high-fluence multi-pass q-switched laser treatment of tattoos with a transparent perfluorodecalin-infused patch: A pilot study.

    Science.gov (United States)

    Biesman, Brian S; O'Neil, Michael P; Costner, Cara

    2015-10-01

    Perfluorodecalin (PFD) has previously been shown to rapidly dissipate the opaque, white micro-bubble layer formed after exposure of tattoos to Q-switched lasers [1]. The current pilot study was conducted to qualitatively determine if the use of a transparent PFD-infused silicone patch would result in more rapid clearance of tattoos than conventional through-air techniques. Black or dark blue tattoos were divided into two halves in a single-site IRB-approved study with 17 subjects with Fitzpatrick skin types I-III. One half of each tattoo served as its own control and was treated with one pass of a standard Q-switched Alexandrite laser (755 nm). The other half of the tattoo was treated directly through a transparent perfluorodecalin (PFD) infused patch (ON Light Sciences, Dublin, CA). The rapid whitening reduction effect of the Patch routinely allowed three to four laser passes in a total of approximately 5 minutes. Both sides were treated at highest tolerated fluence, but the optical clearing, index-matching, and epidermal protection properties of the PFD Patch allowed significantly higher fluence compared to the control side. Standard photographs were taken at baseline, immediately prior to treatment with the PFD Patch in place, and finally before and after each treatment session. Treatments were administered at 4- to 6-week intervals. In a majority of subjects (11 of 17), tattoos treated through a transparent PFD-infused patch showed more rapid tattoo clearance with higher patient and clinician satisfaction than conventional treatment. In no case did the control side fade faster than the PFD Patch side. No unanticipated adverse events were observed. Rapid multi-pass treatment of tattoos with highest tolerated fluence facilitated by a transparent PFD-infused patch clears tattoos more rapidly than conventional methods. © 2015 Wiley Periodicals, Inc.

  6. The influence of the Q-switched and free-running Er:YAG laser beam characteristics on the ablation of root canal dentine

    International Nuclear Information System (INIS)

    Papagiakoumou, Eirini; Papadopoulos, Dimitrios N.; Khabbaz, Marouan G.; Makropoulou, Mersini I.; Serafetinides, Alexander A.

    2004-01-01

    Laser based dental treatment is attractive to many researchers. Lasers in the 3 μm region, as the Er:YAG, are suitable especially for endodontic applications. In this study a pulsed free-running and Q-switched laser was used for the ablation experiments of root canal dentine. The laser beam was either directly focused on the dental tissue or delivered to it through an infrared fiber. For different spatial beam distributions, energies, number of pulses and both laser operations the quality characteristics (crater's shape formation, ablation efficiency and surface characteristics modification) were evaluated using scanning electron microscopy (SEM). The craters produced, generally, reflect the relevant beam profile. Inhomogeneous spatial beam profiles and short pulse duration result in cracks formation and lower tissue removal efficiency, while longer pulse durations cause hard dentine fusion. Any beam profile modification, due to laser characteristics variations and the specific delivering system properties, is directly reflected in the ablation crater shape and the tissue removal efficiency. Therefore, the laser parameters, as fluence, pulse repetition rate and number of pulses, have to be carefully adjusted in relation to the desirable result

  7. Combination of Q-switched and quasi long-pulsed 1064-nm Nd:YAG laser, non-ablative 1450-nm diode laser, and ablative 10 600-nm carbon dioxide fractional laser for enlarged pores.

    Science.gov (United States)

    Cho, Sung Bin; Noh, Seongmin; Lee, Sang Ju; Kang, Jin Moon; Kim, Young Koo; Lee, Ju Hee

    2010-07-01

    Currently, there is no gold standard for the treatment of enlarged facial pores. In this report, we describe a patient with enlarged nasal pores which were treated with a combination of a non-ablative 1450-nm diode laser, a Q-switched and quasi long-pulsed 1064-nm Nd:YAG laser, and an ablative 10 600-nm carbon dioxide fractional laser system. Four months after the final treatment, the condition of the patient's pores had markedly improved, and the patient was satisfied with the results.

  8. MoTe2 saturable absorber for passively Q-switched Ho,Pr:LiLuF4 laser at ∼3 μm

    Science.gov (United States)

    Yan, Zhengyu; Li, Tao; Zhao, Shengzhi; Yang, Kejian; Li, Dechun; Li, Guiqiu; Zhang, Shuaiyi; Gao, Zijing

    2018-03-01

    Multilayer molybdenum ditelluride (MoTe2) nanosheets were prepared by liquid-phase exfoliation (LPE) method. A YAG-based MoTe2 saturable absorption (SA) was consequently fabricated. The MoTe2-SA was employed in a passively Q-switched Ho,Pr:LiLuF4 laser at 2.95 μm. Under the absorbed pump power of 3.8 W, an average output power of 90 mW was achieved. The shortest pulse duration of 670 ns was generated with an output power of 73 mW and a repetition rate of 76.46 kHz, corresponding to a pulse energy of 0.95 μJ.

  9. Low-threshold, nanosecond, high-repetition-rate vortex pulses with controllable helicity generated in Cr,Nd:YAG self-Q-switched microchip laser

    Science.gov (United States)

    He, Hong-Sen; Chen, Zhen; Li, Hong-Bin; Dong, Jun

    2018-05-01

    A high repetition rate, nanosecond, pulsed optical vortex beam has been generated in a Cr,Nd:YAG self-Q-switched microchip laser pumped by the annular-beam formed with a hollow focus lens. The lasing threshold for vortex pulses is 0.9 W. A pulse width of 6.5 ns and a repetition rate of over 330 kHz have been achieved. The average output power of 1 W and the slope efficiency of 46.6% have been obtained. The helicity of the optical vortices has been controlled by adjusting the tilted angle between Cr,Nd:YAG crystal and output coupler. The work provides a new method for developing pulsed optical vortices for potential applications on quantum communication and optical trapping.

  10. Highly efficient, versatile, self-Q-switched, high-repetition-rate microchip laser generating Ince–Gaussian modes for optical trapping

    Energy Technology Data Exchange (ETDEWEB)

    Jun Dong; Yu He; Xiao Zhou; Shengchuang Bai [Department of Electronics Engineering, School of Information Science and Engineering, Xiamen, 361005 (China)

    2016-03-31

    Lasers operating in the Ince-Gaussian (IG) mode have potential applications for optical manipulation of microparticles and formation of optical vortices, as well as for optical trapping and optical tweezers. Versatile, self-Q-switched, high-peak-power, high-repetition-rate Cr, Nd:YAG microchip lasers operating in the IG mode are implemented under tilted, tightly focused laser-diode pumping. An average output power of over 2 W is obtained at an absorbed pump power of 6.4 W. The highest optical-to-optical efficiency of 33.2% is achieved at an absorbed pump power of 3.9 W. Laser pulses with a pulse energy of 7.5 μJ, pulse width of 3.5 ns and peak power of over 2 kW are obtained. A repetition rate up to 335 kHz is reached at an absorbed pump power of 5.8 W. Highly efficient, versatile, IG-mode lasers with a high repetition rate and a high peak power ensure a better flexibility in particle manipulation and optical trapping. (control of laser radiation parameters)

  11. Combined therapy using Q-switched ruby laser and bleaching treatment with tretinoin and hydroquinone for periorbital skin hyperpigmentation in Asians.

    Science.gov (United States)

    Momosawa, Akira; Kurita, Masakazu; Ozaki, Mine; Miyamoto, Shinpei; Kobayashi, Yo; Ban, Izumi; Harii, Kiyonori

    2008-01-01

    Periorbital skin hyperpigmentation, so-called dark circles, is of major concern for many people. However, only a few reports refer to the morbidity and treatment, and as far as the authors know, there are no reports of the condition in Asians. A total of 18 Japanese patients underwent combined therapy using Q-switched ruby laser to eliminate dermal pigmentation following topical bleaching treatment with tretinoin aqueous gel and hydroquinone ointment performed initially (6 weeks) to reduce epidermal melanin. Both steps were repeated two to four times until physical clearance of the pigmentation was confirmed and patient satisfaction was achieved. Skin biopsy was performed at baseline in each patient and at the end of treatment in three patients, all with informed consent. Clinical and histologic appearances of periorbital hyperpigmentation were evaluated and rated as excellent, good, fair, poor, or default. Seven of 18 patients (38.9 percent) showed excellent clearing after treatment and eight (44.4 percent) were rated good. Only one (5.6 percent) was rated fair and none was rated poor. Postinflammatory hyperpigmentation was observed in only two patients (11.1 percent). Histologic examination showed obvious epidermal hyperpigmentation in 10 specimens. Dermal pigmentation was observed in all specimens but was not considered to be melanocytosis. Remarkable reduction of dermal pigmentation was observed in the biopsy specimens of three patients after treatment. The new treatment protocol combining Q-switched ruby laser and topical bleaching treatment using tretinoin and hydroquinone is considered effective for improvement of periorbital skin hyperpigmentation, with a low incidence of postinflammatory hyperpigmentation.

  12. Graphene-PVA saturable absorber for generation of a wavelength-tunable passively Q-switched thulium-doped fiber laser in 2.0 µm

    Science.gov (United States)

    Ahmad, H.; Samion, M. Z.; Sharbirin, A. S.; Norizan, S. F.; Aidit, S. N.; Ismail, M. F.

    2018-05-01

    Graphene, a 2D material, has been used for generation of pulse lasers due to the presence of its various fascinating optical properties compared to other materials. Hence in this paper, we report the first demonstration of a thulium doped fiber laser with a wavelength-tunable, passive Q-switched output using a graphene-polyvinyl-alcohol composite film for operation in the 2.0 µm region. The proposed laser has a wavelength-tunable output spanning from 1932.0 nm to 1946.0 nm, giving a total tuning range of 14.0 nm. The generated pulse has a maximum repetition rate and average output power of 36.29 kHz and 0.394 mW at the maximum pump power of 130.87 mW, as well as a pulse width of 6.8 µs at this pump power. The generated pulses have a stable output, having a signal-to-noise ratio of 31.75 dB, and the laser output is stable when tested over a period of 60 min. The proposed laser would have multiple applications for operation near the 2.0 micron region, especially for bio-medical applications and range-finding.

  13. Electro-optic control of a PPLN-unpoled LiNbO3 boundary for low-voltage Q switching of an intracavity frequency-doubled Nd3+:YVO4 laser.

    Science.gov (United States)

    Torregrosa, A J; Maestre, H; Fernández-Pousa, C R; Pereda, J A; Capmany, J

    2009-08-01

    We present a simple technique to integrate an electro-optic Q switch in a periodically poled bulk lithium niobate crystal bounded by two unpoled (monodomain) regions. The technique exploits the high sensitivity to low applied electric fields of the total internal reflection condition in the periodic poled-unpoled boundary for the small grazing incidence angles associated with the diffraction of a focused Gaussian beam that propagates in the periodically poled region with its axis parallel to the boundary. When the arrangement is placed intracavity to a 1064 nm diode-pumped Nd(3+):YVO(4) laser, it performs simultaneously as a Q switch and as a second-harmonic generator, with Q switching starting at applied voltages as low as 1 V over a 500 microm thickness and with no additional optical elements.

  14. Enlarged pores treated with a combination of Q-switched and micropulsed 1064 nm Nd:YAG laser with and without topical carbon suspension: A simultaneous split-face trial

    OpenAIRE

    Chung, HJ; Goo, BC; Lee, HJ; Roh, MR; Chung, KY

    2011-01-01

    Background and aims: Enlarged facial pores remain one of the major cosmetic concerns among Asian females. This study attempted to assess and compare the efficacy of a combination of the Q-switched and quasi long-pulsed (micropulsed) Nd:YAG laser to reduce the size of the enlarged pores with and without an exogenous photoenhancer.

  15. Efficient continuous-wave, broadly tunable and passive Q-switching lasers based on a Tm3+:CaF2 crystal

    Science.gov (United States)

    Liu, Jingjing; Zhang, Cheng; Zu, Yuqian; Fan, Xiuwei; Liu, Jie; Guo, Xinsheng; Qian, Xiaobo; Su, Liangbi

    2018-04-01

    Laser operations in the continuous-wave as well as in the pulsed regime of a 4 at.% Tm3+:CaF2 crystal are reported. For the continuous-wave operation, a maximum average output power of 1.15 W was achieved, and the corresponding slope efficiency was more than 64%. A continuous tuning range of about 160 nm from 1877-2036 nm was achieved using a birefringent filter. Using Argentum nanorods as a saturable absorber, the significant pulsed operation of a passively Q-switched Tm3+:CaF2 laser was observed at 1935.4 nm for the first time, to the best of our knowledge. A maximum output power of 385 mW with 41.4 µJ pulse energy was obtained under an absorbed pump power of 2.04 W. The present results indicate that the Tm3+:CaF2 lasers could be promising laser sources to operate in the eye-safe spectral region.

  16. A Q-switched Ho:YAG laser assisted nanosecond time-resolved T-jump transient mid-IR absorbance spectroscopy with high sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Deyong; Li, Yunliang; Li, Hao; Weng, Yuxiang, E-mail: yxweng@iphy.ac.cn [Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wu, Xianyou [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, Qingxu [School of Physics and Optoelectronic Technology, Dalian University of Technology, No. 2, Linggong Road, Dalian 116023 (China)

    2015-05-15

    Knowledge of dynamical structure of protein is an important clue to understand its biological function in vivo. Temperature-jump (T-jump) time-resolved transient mid-IR absorbance spectroscopy is a powerful tool in elucidating the protein dynamical structures and the folding/unfolding kinetics of proteins in solution. A home-built setup of T-jump time-resolved transient mid-IR absorbance spectroscopy with high sensitivity is developed, which is composed of a Q-switched Cr, Tm, Ho:YAG laser with an output wavelength at 2.09 μm as the T-jump heating source, and a continuous working CO laser tunable from 1580 to 1980 cm{sup −1} as the IR probe. The results demonstrate that this system has a sensitivity of 1 × 10{sup −4} ΔOD for a single wavelength detection, and 2 × 10{sup −4} ΔOD for spectral detection in amide I′ region, as well as a temporal resolution of 20 ns. Moreover, the data quality coming from the CO laser is comparable to the one using the commercial quantum cascade laser.

  17. Mathematical solutions of rate equations of a laser-diode end-pumped passively Q-switched and mode locked Nd-laser with Cr4+:YAG polarized saturable absorber

    International Nuclear Information System (INIS)

    Abdul Ghani, B.; Hammadi, M.

    2012-01-01

    The intracavity frequency-doubling (IFD) of a simultaneous passively Q-switched mode-locked diode-pumped Nd 3 + - laser is studied with a polarized isotropic Cr 4 +: YAG saturable absorber. A general recurrence formula for the mode-locked pulses under the Q-switched envelope at fundamental wavelength has been reconstructed in order to analyze the temporal shape behavior of a single Q-switched envelope with mode-locking pulse trains. This formula has been derived taking into account the impact of the IFD and polarized Cr 4 +: YAG saturable absorber.The presented mathematical model describes the self-induced anisotropy appeared in the polarized Cr 4 +: YAG in the nonlinear stage of the giant pulse formation. For the anisotropic Nd 3 +: YVO 4 active medium, the generated polarized waves are assumed to be fixed through the lasing cycle. Besides, the maximum absorber initial transmission and the minimum mirror reflectivity values have been determined from the second threshold criterion. The calculated numerical results demonstrate the impact of the variation of the input laser parameters (rotational angle of the polarized crystal, absorber initial transmission and the output mirror reflectivity) on the characteristics of the output laser pulse (SH peak power, pulse width, pulse duration and shift pulse position of central mode). The calculated numerical results in this work is in good qualitative and quantitative agreement with the available experimental data reported in the references. (author)

  18. LD-pumped actively Q-switched c-cut Nd:GdVO4 self-Raman laser operating at 1166 and 1176 nm

    Science.gov (United States)

    Sun, Xinzhi; Zhang, Xihe; Li, Shutao; Dong, Yuan

    2017-12-01

    A laser diode pumped actively Q-switched c-cut Nd:GdVO4 self-Raman laser is experimentally investigated. Simultaneous pulse outputs at 1166 nm and 1176 nm corresponding to the Raman shifts of 807 and 882 cm-1 are acquired. At the pulse repetition frequency (PRF) of 20 kHz, the maximum output power is 103 mW at 1166 nm with the incident pump power of 2.31 W, while 1176 nm output power reaches 530 mW with the incident pump power of 4.11 W. The maximum output power of Raman laser is 570 mW with the incident pump power of 4.11 W and the PRF of 30 kHz. With the incident pump power of 3.67 W and the PRF of 30 kHz, the highest diode-to-Stokes optical conversion efficiency of 14.9% is obtained with the corresponding average output power of 547 mW.

  19. Efficient laser emission from cladding waveguide inscribed in Nd:GdVO(4) crystal by direct femtosecond laser writing.

    Science.gov (United States)

    Liu, Hongliang; Tan, Yang; Vázquez de Aldana, Javier R; Chen, Feng

    2014-08-01

    We report on the fabrication of depressed cladding waveguides in Nd:GdVO(4) laser crystal by using femtosecond laser inscription. The cross section of the structure is a circular shape with a diameter of 150 μm. Under the optical pump at 808 nm, the continuous wave (cw) as well as pulsed (Q-switched by graphene saturable absorber) waveguide lasing at 1064 nm has been realized, supporting guidance of both TE and TM polarizations. The maximum output power of 0.57 W was obtained in the cw regime, while the maximum pulse energy of the pulsed laser emissions was up to 19 nJ (corresponding to a maximum average output power of 0.33 W, at a resonant frequency of 18 MHz). The slope efficiencies achieved for the cw and pulsed Nd:GdVO(4) waveguide lasers were as high as 68% and 52%, respectively.

  20. Quasi-CW diode-pumped self-starting adaptive laser with self-Q-switched output.

    Science.gov (United States)

    Smith, G; Damzen, M J

    2007-05-14

    An investigation is made into a quasi-CW (QCW) diode-pumped holographic adaptive laser utilising an ultra high gain (approximately 10(4)) Nd:YVO(4) bounce amplifier. The laser produces pulses at 1064 nm with energy approximately 0.6 mJ, duration laser configuration, the output was amplified to obtain pulses of approximately 5.6 mJ energy, approximately 7 ns duration and approximately 1 MW peak power. The output spatial quality is also M(2)diode-pumped self-adaptive holographic lasers can provide a useful source of high peak power, short duration pulses with excellent spatial quality and narrow linewidth spectrum.

  1. Diode laser in-band pumped, efficient 1645 nm continuous-wave and Q-switched Er:YLuAG lasers with near-diffraction-limited beam quality

    International Nuclear Information System (INIS)

    Li, Jing; Yang, SuHui; He, Tao

    2014-01-01

    Fiber-like Er:YLuAG laser rods were tested for continuous-wave (CW) and Q-switched operation. Two narrow-band laser diodes emitting at 1532 nm were used as pump sources. The pump power was confined in the laser rods via total internal reflection. In CW mode, a maximum output power of 7.2 W was measured from a 30 mm long Er:YLuAG laser rod, corresponding to an optical–optical efficiency of 26% and a slope efficiency of 78%. Er:YLuAG and Er:YAG lasers were compared experimentally and exhibited comparable performance, while the measured central wavelength of the Er:YLuAG laser was 1644.75 nm, slightly longer than the central wavelength of the Er:YAG laser in the same experimental circumstances. In Q-switched mode, an output energy of 3.5 mJ was obtained from a 25 mm Er:YLuAG laser rod with a pulse duration of 100 ns and a pulse repetition frequency of 100 Hz. The pulsed output had near-diffraction-limited beam quality with M 2 values of 1.13 and 1.11 in the x and y directions, respectively. (letter)

  2. Treatment of tattoos with a 755-nm Q-switched alexandrite laser and novel 1064 nm and 532 nm Nd:YAG laser handpieces pumped by the alexandrite treatment beam.

    Science.gov (United States)

    Bernstein, Eric F; Bhawalkar, Jay; Clifford, Joan; Hsia, James

    2010-11-01

    Multi-colored and even black tattoos often require more than one wavelength to remove the target pigment. The authors report here a novel alexandrite laser with two Nd:YAG laser handpieces pumped by the alexandrite treatment beam enabling the delivery of three wavelengths from a single device. To describe and evaluate the effectiveness of a novel Q-switched laser-pumped laser for treating tattoos. Twenty tattoos in 14 subjects were treated at four-week intervals using a combination of available wavelengths (532, 755 and 1064 nm) as determined by the treating physician. Digital cross-polarized photographs were taken before treatment and two months following the fourth and final treatment. Photographs were evaluated by three physician observers blinded as to the treatment condition and rated for clearance by the following scale: 1 = > 95 percent, 2 = 76-95 percent, 3 = 51-75 percent, 4 = 26-50 percent and 5 = 0-25 percent clearance. The average clearance score was 3.1, in the 51-75 percent range, two months following four treatments. No scarring, hyper- or hypopigmentation was noted on post-treatment photographs or by the treating physician. The alexandrite and alexandrite-pumped 532 nm and 1064 nm Q-switched lasers are effective for removing decorative tattoos, and represents the first commercial laser with laser-pumped, laser handpieces.

  3. Treatment of melasma with low fluence, large spot size, 1064-nm Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser for the treatment of melasma in Fitzpatrick skin types II-IV.

    Science.gov (United States)

    Brown, Alia S; Hussain, Mussarat; Goldberg, David J

    2011-12-01

    Melasma is a common condition affecting over six million American women. Treatment of dermal or combined melasma is difficult and does not respond well to conventional topical therapies. Various light sources have been used recently in the treatment of melasma including fractionated ablative and non-ablative lasers as well as intense pulse light. We report the use of low fluence, large spot size Q-switched, Nd:Yag laser for the treatment of melasma in skin types II-IV.

  4. Efficient diode-end-pumped actively Q-switched Nd:YAG/SrWO4/KTP yellow laser.

    Science.gov (United States)

    Cong, Zhenhua; Zhang, Xingyu; Wang, Qingpu; Liu, Zhaojun; Li, Shutao; Chen, Xiaohan; Zhang, Xiaolei; Fan, Shuzhen; Zhang, Huaijin; Tao, Xutang

    2009-09-01

    An efficient intracavity frequency-doubled Raman laser was obtained by using an SrWO(4) Raman medium, an Nd:YAG ceramic gain medium, and a KTP frequency-doubling medium. Three laser cavities, including a two-mirror cavity, a three-mirror coupled cavity, and a folded cavity, were investigated. With the coupled cavity, a 2.93 W, 590 nm laser was obtained at an incident pump power of 16.2 W and a pulse repetition frequency of 20 kHz; the corresponding conversion efficiency was 18.1%. The highest conversion efficiency of 19.2% was obtained at an incident pump power of 14.1 W and a pulse repetition frequency of 15 kHz. The obtained maximum output power and conversion efficiency were much higher than the results previously obtained with intracavity frequency-doubled solid-state Raman lasers.

  5. A 9.61-W, b-cut Tm,Ho:YAP laser in Q-switched mode operation

    Science.gov (United States)

    Li, Guoxing; Yang, Xining; Zhang, Ziqiu; Zhang, Hongda; Zhang, Liang

    2018-02-01

    A high energy of b-cut Tm, Ho:YAlO3 laser is reported in the paper. The laser operated in acousto-optical Qswitched mode at 2.12 μm. The output average power of 9.61 W was achieved at the pulse repetition frequency of 10 kHz ,and the power of 11.6 W was acquired in continuous wave mode. Moreover, the energy per pulse of 0.961 mJ in 64.4 ns was acquired at 10 kHz with a 14.92-kW peak power.

  6. Stable polarization short pulse passively Q-switched monolithic microchip laser with [110] cut Cr4+:YAG

    International Nuclear Information System (INIS)

    Wang, Y; Gong, M; Yan, P; Huang, L; Li, D

    2009-01-01

    A monolithic Nd:YAG microchip laser with [110] cut Cr 4+ :YAG is presented. The output beam is linearly polarized with polarization ratio higher than 100:1. The polarization direction is stable, independent of pump power, crystal temperature, LD temperature. In single longitudinal mode operation, stable 259 ps pulses at 2.5 kHz with 82 kW peak power and diffraction limited beam mode are output. With a simple and compact one-pass Nd:YVO 4 amplifier, 144 kW peak power is achieved. Single longitudinal and fundamental transverse mode is kept after passing through the amplifier stage. The microchip laser can be operated in two longitudinal modes with two sets of output pulses by increasing the pump power

  7. Evanescent fields of laser written waveguides

    Science.gov (United States)

    Jukić, Dario; Pohl, Thomas; Götte, Jörg B.

    2015-03-01

    We investigate the evanescent field at the surface of laser written waveguides. The waveguides are written by a direct femtosecond laser writing process into fused silica, which is then sanded down to expose the guiding layer. These waveguides support eigenmodes which have an evanescent field reaching into the vacuum above the waveguide. We study the governing wave equations and present solution for the fundamental eigenmodes of the modified waveguides.

  8. Treatment of resistant tattoos using a new generation Q-switched Nd:YAG laser: influence of beam profile and spot size on clearance success.

    Science.gov (United States)

    Karsai, Syrus; Pfirrmann, Gudrun; Hammes, Stefan; Raulin, Christian

    2008-02-01

    Multiple treatments of resistant tattoos often result in fibrosis and visible textural changes that lessen response to subsequent treatments. The aim of this study is to evaluate the influence of beam profile and spot size on clearance rates and side effects in the setting of resistant tattoos. Thirty-six professional, black tattoos (32 patients) were treated unsuccessfully with a Q-switched Nd:YAG laser (MedLite C3, HoyaConBio Inc., Fremont, CA). Because of therapy resistance all tattoos were re-treated using a new generation Nd:YAG laser (MedLite C6, HoyaConBio Inc.). Maximum energy fluence (E (max)), mean energy fluence, mean spot size, level of clearance, side effects and beam profile (irradiance distribution) of both laser systems were assessed and evaluated in a retrospective study. All tattoos were previously treated with the C3 laser at 1,064 nm using a mean E(max) of 5.8+/-0.8 J/cm(2) (range 3.8-7.5 J/cm(2)) as compared with a mean E(max) of 6.4+/-1.6 J/cm(2) (range 3.2-9.0 J/cm(2)) during the C6 treatment course. Corresponding spot sizes were larger during C6 treatments as compared with C3 (5.0+/-0.9 and 3.6+/-0.2 mm, respectively). The C6 laser had a "flat top" and homogenous profile regardless of the spot size. For the C3 laser the beam shape was "Gaussian," and the homogeneity was reduced by numerous micro-spikes and micro-nadirs. After the C6 treatment course 33.3% of the tattoos showed clearance of grade 1 (0-25%), 16.7% of grade 2 (26-50%), 16.7% of grade 3 (51-75%), 30.5% of grade 4 (76-95%), 2.8% of grade 5 (96-100%). The total rate of side effects due to C6 treatment was 8.3% in all tattoos (hyperpigmentation 5.6%, hypopigmentation 2.7%, textural changes/scars 0%). This clinical study documents for the first time the impact of a 1,064-nm Nd:YAG laser with a more homogenous beam profile and a larger spot size on the management of resistant tattoos. Only a few treatment sessions were necessary to achieve an additional clearance with a low rate of

  9. Long-term evaluation of ink clearance in tattoos with different color intensity using the 1064-nm Q-switched Nd:YAG laser.

    Science.gov (United States)

    Mankowska, Agata; Kasprzak, Wojciech; Adamski, Zygmunt

    2015-12-01

    The aim of the study was to evaluate the efficacy of tattoo removal treatments using the 1064-nm Q-switched (QS) Nd:YAG laser. Today, QS lasers appear to be the most common, effective, and safest methods to treat unwanted markings. A total of 64 patients with 75 unwanted tattoos were enrolled in the study. Tattoo clearance was evaluated according to the color intensity - concentration of pigment: group I (34) - black; group II (41) - gray. Consideration included methods of tattooing and tattoo techniques. In group I, after the first treatment session the median of clearance was 30% (10-50%), while in group II, the median was 50% (40-70%). After the second treatment session, median in group I increased to 40% (30-50%). Median of group II increased to 70% (50-80%). The highest number of treatment in group I was 7. After that, the median grew to 75%, while the highest amount of treatment in group II was 5 and a median of 90% was achieved. Effects were dependent upon the amount of ink deposited in the tissue. Old amateur tattoos and tattoos containing small quantities of ink (technique: shading and lines) demonstrated the quickest and the most efficacious results. Tattoos with large quantities of ink, obtained by filling, required the greatest number of treatment sessions. The final outcome in tattoo clearing can only be assessed following treatment completion, which may in some cases take 2-3 years. Presumably, in some cases, complete clearance is impossible. © 2015 Wiley Periodicals, Inc.

  10. High-power actively Q-switched single-mode 1342 nm Nd:YVO4 ring laser, injection-locked by a cw single-frequency microchip laser.

    Science.gov (United States)

    Koch, Peter; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-30

    In this paper we report on the realization of a single-mode Q-switched Nd:YVO4 ring laser at 1342 nm. Unidirectional and single-mode operation of the ring laser is achieved by injection-locking with a continuous wave Nd:YVO4 microchip laser, emitting a single-frequency power of up to 40 mW. The ring laser provides a single-mode power of 13.9 W at 10 kHz pulse repetition frequency with a pulse duration of 18.2 ns and an excellent beam quality (M2 laser, a power of 8.7 W at 671 nm with a pulse duration of 14.8 ns and a beam propagation factor of M2 < 1.1 is obtained. The 671 nm radiation features a long-term spectral width of 75 MHz.

  11. Enlarged pores treated with a combination of Q-switched and micropulsed 1064 nm Nd:YAG laser with and without topical carbon suspension: A simultaneous split-face trial.

    Science.gov (United States)

    Chung, Hj; Goo, Bc; Lee, Hj; Roh, Mr; Chung, Ky

    2011-01-01

    Enlarged facial pores remain one of the major cosmetic concerns among Asian females. This study attempted to assess and compare the efficacy of a combination of the Q-switched and quasi long-pulsed (micropulsed) Nd:YAG laser to reduce the size of the enlarged pores with and without an exogenous photoenhancer. In twenty five female subjects mean age 34.04 yr and skin type II-IV, a carbon lotion as a photoenhancer was applied on one side of the face (Method 1) and the other side was used as the control (Method 2). The entire face was then treated with a single pass of the 1064 nm Nd:YAG laser in the micropulsed mode, pulse fluence and width of 2.3 J/cm(2) and 300 µsec, respectively. Multiple passes were then delivered in the Q-switched mode (2.5 J/cm(2) and 5 nsec). Three weeks after the final treatment, 75% of the subjects showed improvement with method 1 whereas 67% showed improvement with method 2. No adverse side effects were reported with either method. Although histological confirmation was not performed, we were able to prove both subjectively and objectively that the use of the combination of the micropulsed and Q-switched modes of the Nd:YAG laser was useful in reducing pore size, and that the photoenhancer improved the efficacy.

  12. Dielectric waveguide amplifiers and lasers

    NARCIS (Netherlands)

    Pollnau, Markus

    The performance of semiconductor amplifiers and lasers has made them the preferred choice for optical gain on a micro-chip. In the past few years, we have demonstrated that also rare-earth-ion-doped dielectric waveguides show remarkable performance, ranging from a small-signal gain per unit length

  13. Switching between the mode-locking and Q-switching modes in two-section QW lasers upon a change in the absorber properties due to the Stark effect

    Energy Technology Data Exchange (ETDEWEB)

    Gadzhiyev, I. M., E-mail: idris.intop@mail.ru; Buyalo, M. S. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Gubenko, A. E. [Innolume GmbH (Germany); Egorov, A. Yu.; Usikova, A. A.; Il’inskaya, N. D.; Lyutetskiy, A. V.; Zadiranov, Yu. M.; Portnoi, E. L. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2016-06-15

    The passive Q-switching and mode-locking modes are implemented in two-section lasers with three quantum wells. It is demonstrated that raising the reverse bias on the absorbing section changes its spectral and dynamic properties and, accordingly, leads to a change from the Q-switching mode to mode-locking. The pulse-repetition frequency in the mode-locking mode is 75 GHz, with the product of the pulse duration by the spectrum bandwidth being 0.49, which is close to the theoretical limit. It is shown that, in structures with three quantum wells, strong absorption at the lasing wavelength gives rise to a photocurrent across a section of the saturable absorber, which is sufficient for compensation of the applied bias.

  14. Switching between the mode-locking and Q-switching modes in two-section QW lasers upon a change in the absorber properties due to the Stark effect

    International Nuclear Information System (INIS)

    Gadzhiyev, I. M.; Buyalo, M. S.; Gubenko, A. E.; Egorov, A. Yu.; Usikova, A. A.; Il’inskaya, N. D.; Lyutetskiy, A. V.; Zadiranov, Yu. M.; Portnoi, E. L.

    2016-01-01

    The passive Q-switching and mode-locking modes are implemented in two-section lasers with three quantum wells. It is demonstrated that raising the reverse bias on the absorbing section changes its spectral and dynamic properties and, accordingly, leads to a change from the Q-switching mode to mode-locking. The pulse-repetition frequency in the mode-locking mode is 75 GHz, with the product of the pulse duration by the spectrum bandwidth being 0.49, which is close to the theoretical limit. It is shown that, in structures with three quantum wells, strong absorption at the lasing wavelength gives rise to a photocurrent across a section of the saturable absorber, which is sufficient for compensation of the applied bias.

  15. Q-switched Nd: YAG laser alone or with modified Jessner chemical peeling for treatment of mixed melasma in dark skin types: A comparative clinical, histopathological, and immunohistochemical study.

    Science.gov (United States)

    Saleh, Fatma; Moftah, Noha H; Abdel-Azim, Eman; Gharieb, Marwa G

    2017-10-22

    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. To compare efficacy of Q-switched Nd-YAG laser alone or with modified Jessner's peel in mixed melasma in dark skin. Nineteen patients with mixed melasma received 6 sessions of laser on left side of face and alternating laser and modified Jessner on right side. Evaluation was carried out clinically through modified melasma area and severity index at 1 month after last session. Using histopathological, immunohistochemical, and computerized morphometric analysis, objective evaluation of melanin particle surface area and MART-1-positive cells was performed for pre- and post-treated skin biopsies. There was significant clinical improvement on both sides of face (P  .05). At the sixth laser session on left side of face, ill-defined mottled hypopigmentation was observed in 21.05% of patients. Histopathologically, melanin particle surface area and number of MART-1-positive cells (total, epidermal, and dermal) were significantly decreased after two treatment modalities (P  .05). Low-fluence Q-switched Nd-YAG laser alone and with modified Jessner's peel are equally effective regimens for mixed melasma clinically, histopathologically, and immunohistochemically. However, combined method is preferred, especially in dark skin, for obtaining better cosmetic result with fewer side effects of multiple laser sessions and decreasing cost rate of laser. © 2017 Wiley Periodicals, Inc.

  16. Pulsed Laser Deposition: passive and active waveguides

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav; Flory, F.; Escoubas, L.

    2009-01-01

    Roč. 34, č. 4 (2009), s. 438-449 ISSN 0268-1900 R&D Projects: GA ČR GA202/06/0216 Institutional research plan: CEZ:AV0Z10100522 Keywords : PLD * pulsed laser deposition * laser ablation * passive waveguides * active waveguides * waveguide laser * sensors * thin films * butane detection Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.384, year: 2009

  17. Compact intra-cavity pumped low-threshold passively Q-switched Ho:Sc2SiO5 laser by a LD-pumped Tm:YAP laser at room temperature

    Science.gov (United States)

    Yang, Xiao-tao; Xie, Wen-qiang; Liu, Long; Li, Lin-jun

    2017-08-01

    A compact intra-cavity pumped low-threshold passively Q-switched (PQS) Ho:Sc2SiO5 (Ho:SSO) laser is reported for the first time. The Tm:YAlO3 (Tm:YAP) crystal and the Ho:SSO crystal are placed in the same laser cavity. A laser diode with a central wavelength of 793 nm is used to realize the output of the Ho:SSO laser. Both the continuous wave (CW) and PQS operation are investigated. A Cr2+:ZnSe is used as the saturable absorber in the PQS Ho:SSO laser. For the CW mode, the laser threshold is only 750 mW, which is 980 mW in the PQS mode. A maximum pulse energy of 699 µJ is primarily obtained, corresponding to the pulse width of 96 ns. The maximum repetition frequency is 1.46 kHz. The maximum pulse peak power can be calculated to be 7.28 kW. The beam quality factor M 2 is calculated to be 1.4 with the maximum output power.

  18. Waveguide based external cavity semiconductor lasers

    NARCIS (Netherlands)

    Oldenbeuving, Ruud; Klein, E.J.; Offerhaus, Herman L.; Lee, Christopher James; Verhaegen, M.; Boller, Klaus J.

    2012-01-01

    We report on progress of the project waveguide based external cavity semiconductor laser (WECSL) arrays. Here we present the latest results on our efforts to mode lock an array of tunable, external cavity semiconductor lasers.

  19. Passively Q-switched 1.6 µm Er:YAG laser with a γ-Ga2O3:Co-based glass-ceramics as a saturable absorber

    Science.gov (United States)

    Shi, Yang; Gao, Chunqing; Ye, Qing; Wang, Shuo; Wang, Qing; Gao, Mingwei; Loiko, Pavel; Skoptsov, Nikolai; Dymshits, Olga; Zhilin, Alexander; Zapalova, Svetlana; Tsenter, Marina; Vitkin, Vladimir; Mateos, Xavier; Yumashev, Konstantin

    2018-04-01

    A resonantly pumped passively Q-switched Er:YAG laser operating at 1.617 and 1.645 µm is reported with γ-Ga2O3:Co2+-based glass-ceramics (GCs) as a saturable absorber. The maximum average output power achieved from this laser was 273 mW; the highest pulse energy was 5.9 µJ, corresponding to a pulse duration of 3.0 µs at a repetition frequency of 31 kHz. To the best of our knowledge, this is the first time to use the γ-Ga2O3:Co2+-based GC as a passive Q-switcher for Er:YAG lasers and this is also the first time to obtain 1.617 µm and 1.645 µm pulses with a GC-based saturable absorber.

  20. Novel treatment of Hori′s nevus: A combination of fractional nonablative 2,940-nm Er:YAG and low-fluence 1,064-nm Q-switched Nd:YAG laser

    Directory of Open Access Journals (Sweden)

    Brian Wei Cheng Anthony Tian

    2015-01-01

    Full Text Available Objective: To demonstrate a combination laser therapy to treat Hori′s nevus. Design: A prospective study. Setting: A Singapore-based clinic. Participants: Five female patients, aged 30-46 years, with bilateral malar Hori′s nevus. Measurements: Photographs were taken before treatment and 1 month after laser treatment was completed. These were graded by three independent physicians. The patients were also asked to grade their treatment response subjectively. They were followed up for a total of 3 months after laser treatment to monitor recurrence. Materials and Methods: The fractional nonablative 2,940-nm Er:YAG laser with a fluence of 0.7 J/cm 2, spot size 12 mm, and frequency 15 Hz was used to perform a full-face single-pass treatment. Subsequently, a second pass and third pass over Hori′s nevi were done bilaterally till the clinical endpoint of skin whitening. The 1,064-nm Q-switched (QS Nd:YAG at a fluence of 2.0 J/cm 2 , frequency 2 Hz, and 4-mm spot size was used to deliver multiple passes over Hori′s nevus till erythema with mild petechiae appeared. We repeated the treatment once a week for 3 more consecutive weeks. Results: All five patients had above 80% improvement in their pigmentation and two (skin type III achieved complete 100% clearance. Based on the patients′ subjective assessments, all five of them expressed satisfaction and felt that their pigmentation had improved. There were no complications noted. Conclusion: The fractional nonablative 2940 nm Er:YAG laser and Q-switched 1064nm laser Nd:YAG combination is an effective and safe treatment for Hori′s nevus.

  1. Novel treatment of Hori's nevus: A combination of fractional nonablative 2,940-nm Er:YAG and low-fluence 1,064-nm Q-switched Nd:YAG laser.

    Science.gov (United States)

    Tian, Brian Wei Cheng Anthony

    2015-01-01

    To demonstrate a combination laser therapy to treat Hori's nevus. A prospective study. A Singapore-based clinic. Five female patients, aged 30-46 years, with bilateral malar Hori's nevus. Photographs were taken before treatment and 1 month after laser treatment was completed. These were graded by three independent physicians. The patients were also asked to grade their treatment response subjectively. They were followed up for a total of 3 months after laser treatment to monitor recurrence. The fractional nonablative 2,940-nm Er:YAG laser with a fluence of 0.7 J/cm(2), spot size 12 mm, and frequency 15 Hz was used to perform a full-face single-pass treatment. Subsequently, a second pass and third pass over Hori's nevi were done bilaterally till the clinical endpoint of skin whitening. The 1,064-nm Q-switched (QS) Nd:YAG at a fluence of 2.0 J/cm(2), frequency 2 Hz, and 4-mm spot size was used to deliver multiple passes over Hori's nevus till erythema with mild petechiae appeared. We repeated the treatment once a week for 3 more consecutive weeks. All five patients had above 80% improvement in their pigmentation and two (skin type III) achieved complete 100% clearance. Based on the patients' subjective assessments, all five of them expressed satisfaction and felt that their pigmentation had improved. There were no complications noted. The fractional nonablative 2940 nm Er:YAG laser and Q-switched 1064nm laser Nd:YAG combination is an effective and safe treatment for Hori's nevus.

  2. Low-Cost Real-Time Gas Monitoring Using a Laser Plasma Induced by a Third Harmonic Q-Switched Nd-YAG Laser

    Directory of Open Access Journals (Sweden)

    Syahrun Nur Abdulmadjid

    2005-11-01

    Full Text Available A gas plasma induced by a third harmonic Nd-YAG laser with relatively low pulsed energy (about 10 mJ has favorable characteristics for gas analysis due to its low background characteristics, nevertheless a high power fundamental Nd-YAG laser (100-200 mJ is widely used for laser gas breakdown spectroscopy. The air plasma can be used as a low-cost real-time gas monitoring system such that it can be used to detect the local absolute humidity, while a helium plasma can be used for gas analysis with a high level of sensitivity. A new technique using a helium plasma to improve laser ablation emission spectroscopy is proposed. Namely, the third harmonic Nd-YAG laser is focused at a point located some distance from the target in the 1-atm helium surrounding gas. By using this method, the ablated vapor from the target is excited through helium atoms in a metastable state in the helium plasma.

  3. A promising split-lesion technique for rapid tattoo removal using a novel sequential approach of a single sitting of pulsed CO(2) followed by Q-switched Nd: YAG laser (1064 nm).

    Science.gov (United States)

    Sardana, Kabir; Garg, Vijay K; Bansal, Shivani; Goel, Khushbu

    2013-12-01

    Laser tattoo removal conventionally uses Q-switched (QS) lasers, but they require multiple sittings, and the end results depend largely on the type of tattoo treated. In pigmented skin, due to the competing epidermal pigment results, laser results in tattoo are slow and inadequate. To evaluate the efficacy of a combined use of ultrapulse CO2 and QS Nd:YAG (1064 nm) laser in the treatment of tattoos in Indian skin. A split-lesion trial was carried out in five patients, with the left side of tattoos receiving the QS Nd:YAG (1064 nm) and the right side, a sequential combination of Up CO2 and QS Nd: YAG at 6 weeks interval with a maximum of six sittings. Outcome assessment was carried out by a blinded assessor using standardized photography. An assessment of physician improvement score, side-effects score, and patient satisfaction score was taken during and at the end of the study. There was a statistically significant improvement on the combination side(physician improvement score -3.7 vs. 1.87: P = 0.0019) which occurred earlier with fewer sittings (1.7 vs. 6). There was no statistically significant difference in the side effects. A combination of an Up CO2 laser with QS Nd: YAG laser is a promising tool for rapid and effective removal of blue-black/blue amateur tattoo in pigmented skin. © 2013 Wiley Periodicals, Inc.

  4. Efficient, space-based, PM 100W thulium fiber laser for pumping Q-switched 2μm Ho:YLF for global winds and carbon dioxide lidar

    Science.gov (United States)

    Engin, Doruk; Mathason, Brian; Storm, Mark

    2017-08-01

    Global wind measurements are critically needed to improve and extend NOAA weather forecasting that impacts U.S. economic activity such as agriculture crop production, as well as hurricane forecasting, flooding, and FEMA disaster planning.1 NASA and the 2007 National Research Council (NRC) Earth Science Decadal Study have also identified global wind measurements as critical for global change research. NASA has conducted aircraft-based wind lidar measurements using 2 um Ho:YLF lasers, which has shown that robust wind measurements can be made. Fibertek designed and demonstrated a high-efficiency, 100 W average power continuous wave (CW) 1940 nm thulium (Tm)- doped fiber laser bread-board system meeting all requirements for a NASA Earth Science spaceflight 2 μm Ho:YLF pump laser. Our preliminary design shows that it is possible to package the laser for high-reliability spaceflight operation in an ultra-compact 2″x8″x14″ size and weight <8.5 lbs. A spaceflight 100 W polarization maintaining (PM) Tm laser provides a path to space for a pulsed, Q-switched 2 μm Ho:YLF laser with 30-80 mJ/pulse range at 100-200 Hz repletion rates.

  5. Efficient continuous-wave and passively Q-switched pulse laser operations in a diffusion-bonded sapphire/Er:Yb:YAl3(BO3)4/sapphire composite crystal around 1.55 μm.

    Science.gov (United States)

    Chen, Yujin; Lin, Yanfu; Huang, Jianhua; Gong, Xinghong; Luo, Zundu; Huang, Yidong

    2018-01-08

    A composite crystal consisting of a 1.5-mm-thick Er:Yb:YAl 3 (BO 3 ) 4 crystal between two 1.2-mm-thick sapphire crystals was fabricated by the thermal diffusion bonding technique. Compared with a lone Er:Yb:YAl 3 (BO 3 ) 4 crystal measured under the identical experimental conditions, higher laser performances were demonstrated in the sapphire/Er:Yb:YAl 3 (BO 3 ) 4 /sapphire composite crystal due to the reduction of the thermal effects. End-pumped by a 976 nm laser diode in a hemispherical cavity, a 1.55 μm continuous-wave laser with a maximum output power of 1.75 W and a slope efficiency of 36% was obtained in the composite crystal when the incident pump power was 6.54 W. Passively Q-switched by a Co 2+ :MgAl 2 O 4 crystal, a 1.52 μm pulse laser with energy of 10 μJ and repetition frequency of 105 kHz was also realized in the composite crystal. Pulse width was 315 ns. The results show that the sapphire/Er:Yb:YAl 3 (BO 3 ) 4 /sapphire composite crystal is an excellent active element for 1.55 μm laser.

  6. Evaluation of frequency-doubled Q-switched Nd: YAG laser in the treatment of freckle%倍频Q开关掺钕钇铝石榴石激光治疗雀斑疗效观察

    Institute of Scientific and Technical Information of China (English)

    罗迪青; 张武军; 刘隽华; 张海燕; 何定阳

    2009-01-01

    目的 评估倍频Q开关掺钕钇铝石榴石激光治疗雀斑的疗效.方法 总结2004年10月至2007年8月间治疗的47例雀斑患者的资料及治疗后外涂丁卡因凝胶的效果.结果 治疗后6个月,47例患者中,治愈38例(80.9%),显效8例(17.0%),有效1例(2.1%),总有效率100%.1年后治愈率为100%.治疗后3个月时有15例(31.9%)出现色素沉着,但于9个月内全部消退.治疗后外涂丁卡因凝胶的起效时间为20~70 8,达到最大镇痛效果的时间为2~5 min,可以减轻疼痛70%~100%.结论 倍频Q开关Nd:YAG激光治疗雀斑有疗效好、不良反应少的优点.但可出现可逆性炎症后色素沉着.治疗后使用丁卡因凝胶,有较好的止痛效果.%Objective To evaluate the effects of Q-switched Nd: YAG laser in the treatment of freckle. Methods Fourty-seven cases treated by Q-switched Nd: YAG laser between October 2004 to August. 2007 were analyzed. The effects of post-laser treatment of tetracaine gel were evaluated. Results Of 47 cases, 38 were cured (80.9%), 8 were notablely improved (17.0%) and 1 was improved 6 months after treatment. The total efficient rate was 100%. All of them were cured 1 year after treatment. 15 cases had a postinflammatory hyperpigmentation 3 months after the laser treatment which disappeared in 9 months. Furthermore, when the tetracaine gel was used after the laser treatment, the onset time was 20 to 70 seconds, the time of the maxial decreased-pain was 2 to 5 minutes and the maximal decreased-pain was 70%~100%. Conclusions Frequency-doubled Q-switched Nd: YAG laser is an effective tool to treat freckles without any adverse effects. But some of the patients will have a reversible postin-flammatory hyperpigmentation. Tetracaine gel has a rapid and good effects on laser-induced pain when used immedi-ately after laser procedure.

  7. Split-face comparison of long-pulse-duration neodymium-doped yttrium aluminum garnet (Nd:YAG) 1,064-nm laser alone and combination long-pulse and Q-switched Nd:YAG 1,064-nm laser with carbon photoenhancer lotion for the treatment of enlarged pores in Asian women.

    Science.gov (United States)

    Wattanakrai, Penpun; Rojhirunsakool, Salinee; Pootongkam, Suwimon

    2010-11-01

    Long-pulse and Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 1,064-nm laser used for facial rejuvenation can improve pore size. Topical carbon has been used to enhance efficacy. To compare the efficacy and safety of a 1,064-nm long-pulse Nd:YAG laser alone with that of a combination Q-switched Nd:YAG laser with topical carbon lotion followed by long-pulse Nd:YAG to improve enlarged pores. Twenty Thai women randomly received five treatments with a long-pulse Nd:YAG laser on one facial half (LP side) and long-pulse Nd:YAG after carbon-assisted Q-switched Nd:YAG laser on the contralateral side (carbon QS+LP side) at 2-week intervals. Participants were evaluated using digital photography, complexion analysis, and a chromometer. There was significant decrease in pore counts of 35.5% and 33% from baseline on the carbon QS+LP and LP sides, respectively. Physician-evaluated pore size improvement was 67% on the carbon QS+LP sides and 60% on the LP sides. Chromometer measurement showed an increase in skin lightness index. There was no significant difference between the two treatments, although there were more adverse effects on the carbon QS+LP side. Long-pulse Nd:YAG 1,064-nm laser improves the appearance of facial pores and skin color. Adding carbon-assisted Q-switched Nd:YAG did not enhance the results but produced more side effects. © 2010 by the American Society for Dermatologic Surgery, Inc.

  8. The waveguide Free-Electron Laser. 14

    International Nuclear Information System (INIS)

    Walsh, J.E.

    1990-01-01

    The general characteristics of free-electron lasers (FELs) which employ a waveguiding structure to confine electromagnetic fields and to couple them to the electron beam is discussed. The mode structure of the basic parallel plate waveguide and its adaptation via quasi-optical techniques to FEL resonator design are considered in detail. A summary of the theory of FEL systems which depend intrinsically on a guide structure (micro-undulator, Cerenkov and metal-grating FELs) and a review of progress on waveguide FEL experiments are also presented. (author). 44 refs.; 16 figs

  9. Over 8 W high peak power UV laser with a high power Q-switched Nd:YVO4 oscillator and the compact extra-cavity sum-frequency mixing

    International Nuclear Information System (INIS)

    Yan, X P; Liu, Q; Gong, M; Wang, D S; Fu, X

    2009-01-01

    A 8.2 W UV laser was reported with the compact extra-cavity sum-frequency mixing. The IR fundamental frequency source was a high power and high beam quality Q-switched Nd:YVO 4 oscillator. 38 W fundamental frequency laser at 1064 nm was obtained at the pulse repetition rate of 450 kHz with the beam quality factors of M 2 x = 1.27, M 2 y = 1.21. The type I and type II phase-matched LBO crystals were used as the extra-cavity frequency doubling and mixing crystals respectively. At 38 kHz, 8.2 W UV laser at 355 nm was achieved with the pulse duration of 8 ns corresponding to the pulse peak power as high as 27 kW, and the optical-optical conversion efficiency from IR to UV was 25.6%. The output characteristics of the IR and the harmonic generations varying with the pulse repetition rate were also investigated detailedly

  10. Continuous-wave and passively Q-switched cryogenic Yb: KLu(WO.sub.4./sub.).sub.2./sub. laser

    Czech Academy of Sciences Publication Activity Database

    Navrátil, Petr; Jambunathan, Venkatesan; Paul David, Samuel; Yue, Fangxin; Serres, J.M.; Mateos, X.; Aguilo, M.; Diaz, F.; Griebner, U.; Petrov, V.; Lucianetti, Antonio; Mocek, Tomáš

    2017-01-01

    Roč. 25, č. 21 (2017), s. 25886-25893 ISSN 1094-4087 R&D Projects: GA MŠk LO1602; GA MŠk LM2015086 EU Projects: European Commission(XE) 739573 - HiLASE CoE Grant - others:OP VVV - HiLASE-CoE(XE) CZ.02.1.01/0.0/0.0/15_006/0000674 Institutional support: RVO:68378271 Keywords : diode-pumped lasers * laser materials Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 3.307, year: 2016

  11. Ultrafast Laser Fabrication of Bragg Waveguides in GLS Chalcogenide Glass

    Directory of Open Access Journals (Sweden)

    McMillen Ben

    2013-11-01

    Full Text Available We present work on the fabrication of Bragg waveguides in gallium-lanthanum-sulfide chalcogenide glass using an ultrafast laser. Waveguides were written with a single pass while modulating the writing beam. The spatial and temporal profile of the writing beam was ontrolled during waveguide fabrication in order to control the shape and size of the waveguide cross-section.

  12. Diode array pumped, non-linear mirror Q-switched and mode-locked

    Indian Academy of Sciences (India)

    A non-linear mirror consisting of a lithium triborate crystal and a dichroic output coupler are used to mode-lock (passively) an Nd : YVO4 laser, pumped by a diode laser array. The laser can operate both in cw mode-locked and simultaneously Q-switched and mode-locked (QML) regime. The peak power of the laser while ...

  13. High-power repetitively pulsed CO{sub 2} laser with mechanical Q-switching and its application to studies in aerodynamic installations

    Energy Technology Data Exchange (ETDEWEB)

    Malov, Aleksei N; Orishich, Anatolii M; Shulyat' ev, Viktor B [S.A. Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2011-11-30

    A new method for organising the repetitively pulsed regime of CO{sub 2} laser oscillation at the expense of a self-filtering resonator and two concave cylindrical mirrors with equal curvature in the intracavity modulator is considered. The studies of the energy and temporal characteristics of the laser radiation show that the constructed laser has high efficiency close to that of a cw laser. The mean and pulse power of 4.5 and 200 kW, respectively, are obtained. For a wide range of gas-dynamic characteristics the possibility of the optical breakdown in the supersonic wide-aperture air flow is demonstrated. The coefficient of absorption of laser radiation in optical breakdown plasma in a supersonic air flow is investigated and its value amounting to 60% is obtained. For the first time it is found that the threshold density of air, corresponding to the efficiency jump, is equal to 1.8 - 2 kg m{sup -3} and independent of the Mach number M = 1.7 - 3.7. (lasers)

  14. Laser generated soliton waveguides in photorefractive crystals

    International Nuclear Information System (INIS)

    Vlad, V.I.; Fazio, E.; Bertolotti, M.; Bosco, A.; Petris, A.

    2005-01-01

    Non-linear photo-excited processes using the photorefractive effect are revisited with emphasis on spatial soliton generation in special laser beam propagation conditions. The soliton beams can create reversible or irreversible single-mode waveguides in the propagating materials. The important features are the 3D orientation and graded index profile matched to the laser fundamental mode. Bright spatial solitons are theoretically demonstrated and experimentally observed for the propagation of c.w. and pulsed femtosecond laser beams in photorefractive materials such as Bi 12 SiO 20 (BSO) and lithium niobate crystals. Applications in high coupling efficiency, adaptive optical interconnections and photonic crystal production are possible

  15. 16.7 W 885 nm diode-side-pumped actively Q -switched Nd:YAG/YVO4 intracavity Raman laser at 1176 nm

    International Nuclear Information System (INIS)

    Jiang, Pengbo; Zhang, Guizhong; Liu, Jian; Ding, Xin; Sheng, Quan; Sun, Bing; Shi, Rui; Wu, Liang; Yao, Jianquan; Yu, Xuanyi; Wang, Rui

    2017-01-01

    We proposed and experimentally demonstrated the generation of high-power 1176 nm Stokes wave by frequency shifting of a 885 nm diode-side-pumped Nd:YAG laser using a YVO 4 crystal in a Z -shaped cavity configuration. Employing the 885 nm diode-side-pumped scheme and the Z -shaped cavity, for the first time to our knowledge, we realized the thermal management effectively, achieving excellent 1176 nm Stokes wave consequently. With an incident pump power of ∼190.0 W, a maximum average output power of 16.7 W was obtained at the pulse repetition frequency of 10 kHz. The pulse duration and spectrum linewidth of the Stokes wave at the maximum output power were 20.3 ns and ∼0.08 nm, respectively. (paper)

  16. Femtosecond laser written waveguides deep inside silicon.

    Science.gov (United States)

    Pavlov, I; Tokel, O; Pavlova, S; Kadan, V; Makey, G; Turnali, A; Yavuz, Ö; Ilday, F Ö

    2017-08-01

    Photonic devices that can guide, transfer, or modulate light are highly desired in electronics and integrated silicon (Si) photonics. Here, we demonstrate for the first time, to the best of our knowledge, the creation of optical waveguides deep inside Si using femtosecond pulses at a central wavelength of 1.5 μm. To this end, we use 350 fs long, 2 μJ pulses with a repetition rate of 250 kHz from an Er-doped fiber laser, which we focused inside Si to create permanent modifications of the crystal. The position of the beam is accurately controlled with pump-probe imaging during fabrication. Waveguides that were 5.5 mm in length and 20 μm in diameter were created by scanning the focal position along the beam propagation axis. The fabricated waveguides were characterized with a continuous-wave laser operating at 1.5 μm. The refractive index change inside the waveguide was measured with optical shadowgraphy, yielding a value of 6×10 -4 , and by direct light coupling and far-field imaging, yielding a value of 3.5×10 -4 . The formation mechanism of the modification is discussed.

  17. Q-switched nanosecond Nd3+:Ca(NbO3)2 crystalline self-Raman laser with single-step cascade SE (λSE = 1.0615 μm of 4F3/2 → 4I11/2 channel) → SRS (λSt1 = 1.1741 μm of ωSRS ≈ 904 cm-1 promotion vibration mode) wavelength conversion

    International Nuclear Information System (INIS)

    Kaminskii, A A; Dong, J; Ueda, K; Bettinelli, M; Grinberg, M; Jaque, D

    2009-01-01

    A passively Q-switched nanosecond Nd 3+ :Ca(NbO 3 ) 2 self-Raman laser with 0.808-μm laser-diode pumping has been demonstrated, operating by nonlinear cascaded scheme at converted wavelength of Nd 3+ one-micron stimulated emission

  18. Tungsten disulphide based all fiber Q-switching cylindrical-vector beam generation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.; Yan, K.; Zhou, Y. [Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026 (China); Xu, L. X., E-mail: xulixin@ustc.edu.cn; Gu, C. [Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026 (China); Haixi Collaborative Innovation Center for New Display Devices and Systems Integration, Fuzhou University, Fuzhou 350002 (China); Zhan, Q. W. [Electro-Optics Program, University of Dayton, Dayton, Ohio 45469 (United States)

    2015-11-09

    We proposed and demonstrated an all fiber passively Q-switching laser to generate cylindrical-vector beam, a two dimensional material, tungsten disulphide (WS{sub 2}), was adopted as a saturable absorber inside the laser cavity, while a few-mode fiber Bragg grating was used as a transverse mode-selective output coupler. The repetition rate of the Q-switching output pulses can be varied from 80 kHz to 120 kHz with a shortest duration of 958 ns. Attributed to the high damage threshold and polarization insensitivity of the WS{sub 2} based saturable absorber, the radially polarized beam and azimuthally polarized beam can be easily generated in the Q-switching fiber laser.

  19. Ti:Sapphire waveguide lasers

    NARCIS (Netherlands)

    Pollnau, Markus; Pashinin, P.P.; Grivas, C.; Laversenne, L.; Wilkinson, J.S.; Eason, R.W.; Shepherd, D.P.

    2007-01-01

    Titanium-doped sapphire is one of the most prominent laser materials and is appreciated for its excellent heat conductivity and broadband gain spectrum, allowing for a wide wavelength tunability and generation of ultrashort pulses. As one of the hardest materials, it can also serve as a model system

  20. 蛋白胶-罂粟碱复合体促进调Q Nd:YAG激光治疗后创面愈合的观察%Using Fibrin Glue Papaverine Complex to Promote Wounds Healing after Q-Switched Laser

    Institute of Scientific and Technical Information of China (English)

    朱玉; 李栋梁; 陈志勇; 谭强; 周业松

    2011-01-01

    目的 观察蛋白胶-罂粟碱复合体对调Q Nd:YAG激光治疗后创面愈合的促进作用.方法 太田痣患者50例,随机分为研究组和对照组,每组25例.以调Q Nd:YAG激光治疗后,分别应用蛋白胶-罂粟碱复合体或凡士林纱布覆盖创面,对比观察两组患者创面疼痛评分、止血时间及愈合时间.结果 研究组在创面疼痛评分、止血时间、创面愈合时间均优于对照组.结论 蛋白胶-罂粟碱复合体对调Q Nd:YAG激光治疗后的创面具有明显的减轻疼痛,促进愈合的作用.%Objective To observe the effects of using fibrin glue papaverine complex to promote wound healing after Q-switched laser therapy.Methods Fifty patients with nevus of Ota were randomly and equally assigned to two groupa: the study group applied fibrin glue papaverine complex and the control group applied vaseline gauze,and their wounds pain, hemostatic lime and healing time were compared.Results Covering wounds with glue papaverine complex after Q-switched laser was superior to the other therapy from aspects of pain alleviation, hemostatic time and healing time.Conclusions Covering wounds with glue papaverine complex after the treatment of Q-switched laser can alleviate the pain and accelerate the wound healing.

  1. Femtosecond laser inscribed cladding waveguide lasers in Nd:LiYF4 crystals

    Science.gov (United States)

    Li, Shi-Ling; Huang, Ze-Ping; Ye, Yong-Kai; Wang, Hai-Long

    2018-06-01

    Depressed circular cladding, buried waveguides were fabricated in Nd:LiYF4 crystals with an ultrafast Yb-doped fiber master-oscillator power amplifier laser. Waveguides were optimized by varying the laser writing conditions, such as pulse energy, focus depth, femtosecond laser polarization and scanning velocity. Under optical pump at 799 nm, cladding waveguides showed continuous-wave laser oscillation at 1047 nm. Single- and multi-transverse modes waveguide laser were realized by varying the waveguide diameter. The maximum output power in the 40 μm waveguide is ∼195 mW with a slope efficiency of 34.3%. The waveguide lasers with hexagonal and cubic cladding geometry were also realized.

  2. ytterbium- & erbium-doped silica for planar waveguide lasers & amplifiers

    DEFF Research Database (Denmark)

    Dyndgaard, Morten Glarborg

    2001-01-01

    The purpose of this work was to demonstrate ytterbium doped planar components and investigate the possibilities of making erbium/ytterbium codoped planar waveguides in germano-silica glass. Furthermore, tools for modelling lasers and erbium/ytterbium doped amplifiers. The planar waveguides were...

  3. Single-transverse-mode Ti:sapphire rib waveguide laser

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, Markus

    2005-01-01

    Laser operation of Ti:sapphire rib waveguides fabricated using photolithography and ion beam etching in pulsed laser deposited layers is reported. Polarized laser emission was observed at 792.5 nm with an absorbed pump power threshold of 265 mW, which is more than a factor of 2 lower in comparison

  4. Optically amplifying planar glass waveguides: Laser on a chip

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas

    with UV-light and that permanent Bragg-gratings can be induced. Planar waveguide lasers with integrated Bragg-gratings are manufactured and characterised. It is shown that linewidths below 125 kHz and output powers around 0.5 mW can be obtained, and that the manufactured lasers are resistant to mechanical...... lightwave circuits, as well as provide the gain medium for integrated planar waveguide lasers. The work and the obtained results are presented in this thesis: The manufacturing of silica thin films is described and it is shown that the refractive index of the films can be controlled by germanium co...... as well as thermal influence. A simple method for producing an array of planar waveguide lasers is presented and it is shown that the difference in output wavelength of the individual lasers can be controlled with great accuracy....

  5. Planar waveguide amplifiers and laser in erbium doped silica

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas; Kristensen, Martin

    1999-01-01

    with UV-light and that permanent Bragg-gratings can be induced. Planar waveguide lasers with integrated Bragg-gratings are manufactured and characterised. It is shown that linewidths below 125 kHz and output powers around 0.5 mW can be obtained, and that the manufactured lasers are resistant to mechanical...... lightwave circuits, as well as provide the gain medium for integrated planar waveguide lasers. The work and the obtained results are presented in this thesis: The manufacturing of silica thin films is described and it is shown that the refractive index o fthe films can be controlled by germanium co...... as well as thermal influence. A simple method for producing an array of planar waveguide lasers is presented and it is shown that the difference in output wavelength of the individual lasers can be controlled with great accuracy....

  6. All-fibre Q-switching YDFL operation with bismuth-doped fibre as saturable absorber

    Science.gov (United States)

    Muhammad, A. R.; Haris, H.; Arof, H.; Tan, S. J.; Ahmad, M. T.; Harun, S. W.

    2018-05-01

    We demonstrate the generation of a passively Q-switched ytterbium-doped fibre laser (YDFL) using a bismuth-doped fibre (BDF) as a solid-state fibre saturable absorber (FSA) in a ring cavity. The BDF used has a wide and low absorption band of 5 dB/m at the 1.0 μm region due to the ion transition of ? that occurs around the region. When introduced into a YDFL laser cavity, a stable Q-switched pulse operation was observed and the pulse repetition rate was proportional to the input pump power. It was limited to 72.99 kHz by the maximum power that the laser diode could supply. Meanwhile, the pulse width decreased from 12.22 to 4.85 μs as the pump power was increased from 215.6 to 475.6 mW. The finding suggests that BDF could be used as a potential SA for the development of robust, compact, efficient and low cost Q-switched fibre lasers operating at 1 micron region.

  7. Femtosecond laser inscribed cladding waveguides in Nd:YAG ceramics: fabrication, fluorescence imaging and laser performance.

    Science.gov (United States)

    Liu, Hongliang; Jia, Yuechen; Vázquez de Aldana, Javier Rodríguez; Jaque, Daniel; Chen, Feng

    2012-08-13

    We report on the fabrication of depressed cladding waveguide lasers in Nd:YAG (neodymium doped yttrium aluminum garnet, Nd:Y3Al5O12) ceramics microstructured by femtosecond laser pulses. Full control over the confined light spatial distribution is demonstrated by the fabrication of high contrast waveguides with hexagonal, circular and trapezoidal configurations. The confocal fluorescence measurements of the waveguides reveal that the original luminescence features of Nd3+ ions are well-preserved in the waveguide regions. Under optical pump at 808 nm, cladding waveguides showed continuous wave efficient laser oscillation. The maximum output power obtained at 1064.5 nm is ~181 mW with a slope efficiency as high as 44%, which suggests that the fabricated Nd:YAG ceramic waveguides are promising candidates for efficient integrated laser sources.

  8. Fabrication, operation, and applications of efficient dielectric waveguide lasers

    NARCIS (Netherlands)

    Pollnau, Markus; van Dalfsen, Koop; Bernhardi, Edward; Geskus, D.; Worhoff, Kerstin; de Ridder, R.M.; García Blanco, Sonia Maria

    This paper reviews our recent results on rare-earth-ion-doped integrated lasers. We have concentrated our efforts on crystalline potassium double tungstates and amorphous aluminum oxide. In the former material class we have demonstrated channel waveguide lasers based on Yb3+ doping, operating near 1

  9. Development of the RTP crystal applications for Q-switching operation and second harmonics generation

    International Nuclear Information System (INIS)

    Alnayli, R.Sh.

    2010-01-01

    Complete text of publication follows. A dialed theoretical studies on performances of the ideal RTP crystal for the electro optical applications as Q-switching laser operation and for nonlinear optics application as second harmonics generation are accomplished in this paper. Single or pair RTP crystal of excellent quality with dimensions 5 x 5 x 7.5 mm 3 have proposed as element model to combined Q-switching operation and frequency doublers for 1.06 μm wave length laser. In order to get and interpolate the optimum conditions to combined both of these operations by application this RTP model. The main am of this work was investigated the most influent parameters on the performance of the electro optical Q-switching laser operation such as, the voltage requirement, contrast and extinction ratios, the birefringence effective and withstand threshold on the other hand the influences of the ray walk off, thermal effective on the efficiency of the second harmonics generation as well are investigated. The results were satisfied for the goals of this paper.

  10. Nd:Ta2O5 rib waveguide lasers

    International Nuclear Information System (INIS)

    Unal, Bayram; Tai, C.-Y.; Shepherd, David P.; Wilkinson, James S.; Perney, Nicolas M.B.; Netti, M. Caterina; Parker, Gregory J.

    2005-01-01

    Ta 2 O 5 waveguides offer great potential for high-density active photonic crystal circuits and their combination with rare-earth dopants for active devices is of interest for increasing their potential functionality. To this end, neodymium-doped Ta 2 O 5 rib waveguide lasers have been fabricated on an oxidized silicon wafer by rf sputtering and argon ion-beam milling and laser action in this material has been demonstrated. Lasing was observed at wavelenghts between 1060 and 1080 nm and an absorbed pump power threshold of 87 mW was obtained

  11. Planar waveguide laser in Er/Al-doped germanosilicate

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas; Hübner, Jörg; Kristensen, Martin

    1999-01-01

    A singlemode DBR laser is demonstrated in an Er/Al-doped germanosilicate planar waveguide. 0.4 mW of output power has been obtained at 1.553 mu m using internal Bragg reflectors produced by UV-induced index modulations.......A singlemode DBR laser is demonstrated in an Er/Al-doped germanosilicate planar waveguide. 0.4 mW of output power has been obtained at 1.553 mu m using internal Bragg reflectors produced by UV-induced index modulations....

  12. Comparison of Small-Scale Actively and Passively Q-Switched Eye-Safe Intracavity Optical Parametric Oscillators at 1.57 μm

    International Nuclear Information System (INIS)

    Miao Jie-Guang; Pan Yu-Zhai; Qu Shi-Liang

    2012-01-01

    The first experimental comparison between the actively and passively Q-switched intracavity optical parametric oscillators (IOPOs) at 1.57 μm driven by a small-scale diode-pumped Nd:YVO 4 laser are thoroughly presented. It is found that the performances of the two types of IOPOs are complementary. The actively Q-switched IOPO features a shorter pulse duration, a higher peak power, and a superior power and pulse stability. However, in terms of compactness, operation threshold and conversion efficiency, passively Q-switched IOPOs are more attractive. It is further indicated that the passively Q-switched IOPO at 1.57μm is a promising and cost-effective eye-safe laser source, especially at the low and moderate output levels. In addition, instructional improvement measures for the two types of IOPOs are also summarized. (fundamental areas of phenomenology(including applications))

  13. Near-infrared lasers and self-frequency-doubling in Nd:YCOB cladding waveguides.

    Science.gov (United States)

    Ren, Yingying; Chen, Feng; Vázquez de Aldana, Javier R

    2013-05-06

    A design of cladding waveguides in Nd:YCOB nonlinear crystals is demonstrated in this work. Compact Fabry-Perot oscillation cavities are employed for waveguide laser generation at 1062 nm and self-frequency-doubling at 531 nm, under optical pump at 810 nm. The waveguide laser shows slope efficiency as high as 55% at 1062 nm. The SFD green waveguide laser emits at 531 nm with a maximum power of 100 μW.

  14. Femtosecond laser writing of waveguides in zinc phosphate glasses [Invited

    NARCIS (Netherlands)

    Fletcher, L.B.; Witcher, J.J.; Troy, N.; Reis, S.T.; Brow, R.K.; Martinez Vazquez, R.; Osellame, R.; Krol, D.M.

    2011-01-01

    We have studied the relationship between the initial glass composition and the structural changes associated with laser-induced refractive index modification in a series of Er-Yb doped and undoped zinc phosphate glasses. White light microscopy and waveguide experiments are used together with Raman

  15. A hybrid plasmonic waveguide terahertz quantum cascade laser

    Energy Technology Data Exchange (ETDEWEB)

    Degl' Innocenti, Riccardo, E-mail: rd448@cam.ac.uk; Shah, Yash D.; Wallis, Robert; Klimont, Adam; Ren, Yuan; Jessop, David S.; Beere, Harvey E.; Ritchie, David A. [Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2015-02-23

    We present the realization of a quantum cascade laser emitting at around 2.85 THz, based on a hybrid plasmonic waveguide with a low refractive index dielectric cladding. This hybrid waveguide design allows the performance of a double-metal waveguide to be retained, while improving the emission far-field. A set of lasers based on the same active region material were fabricated with different metal layer thicknesses. A detailed characterization of the performance of these lasers revealed that there is an optimal trade-off that yields the best far-field emission and the maximum temperature of operation. By exploiting the pure plasmonic mode of these waveguides, the standard operation conditions of a double-metal quantum cascade laser were retrieved, such that the maximum operating temperature of these devices is not affected by the process. These results pave the way to realizing a class of integrated devices working in the terahertz range which could be further exploited to fabricate terahertz on-chip circuitry.

  16. Guiding of laser pulses in plasma waveguides created by linearly-polarized femtosecond laser pulses

    OpenAIRE

    Lemos, N.; Cardoso, L.; Geada, J.; Figueira, G.; Albert, F.; Dias, J. M.

    2018-01-01

    We experimentally demonstrate that plasma waveguides produced with ultra-short laser pulses (sub-picosecond) in gas jets are capable of guiding high intensity laser pulses. This scheme has the unique ability of guiding a high-intensity laser pulse in a plasma waveguide created by the same laser system in the very simple and stable experimental setup. A hot plasma column was created by a femtosecond class laser that expands into an on-axis parabolic low density profile suitable to act as a wav...

  17. Monolithic micro-laser with KTP ridge waveguides for injection seeding high power lasers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This NASA Small Business Innovation Research Phase I project will develop a technique to greatly improve the direct coupling of a diode laser to an optical waveguide...

  18. Fluorescence imaging of lattice re-distribution on step-index direct laser written Nd:YAG waveguide lasers

    Energy Technology Data Exchange (ETDEWEB)

    Martínez de Mendívil, Jon; Pérez Delgado, Alberto; Lifante, Ginés; Jaque, Daniel [Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid 28049 (Spain); Ródenas, Airán [Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona 43007 (Spain); Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Benayas, Antonio, E-mail: antonio.benayas@emt.inrs.ca [Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid 28049 (Spain); Institut National de la Recherche Scientifique, Centre – Énergie Matériaux et Télécommunications, 1650, Boul. Lionel Boulet Varennes, Quebec J3X 1S2 (Canada); Aguiló, Magdalena; Diaz, Francesc [Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona 43007 (Spain); Kar, Ajoy K. [Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)

    2015-01-14

    The laser performance and crystalline micro-structural properties of near-infrared step-index channel waveguides fabricated inside Neodymium doped YAG laser ceramics by means of three-dimensional sub-picosecond pulse laser direct writing are reported. Fluorescence micro-mapping of the waveguide cross-sections reveals that an essential crystal lattice re-distribution has been induced after short pulse irradiation. Such lattice re-distribution is evidenced at the waveguide core corresponding to the laser written refractive index increased volume. The waveguides core surroundings also present diverse changes including slight lattice disorder and bi-axial strain fields. The step-index waveguide laser performance is compared with previous laser fabricated waveguides with a stress-optic guiding mechanism in absence of laser induced lattice re-distribution.

  19. Index-antiguided planar waveguide lasers with large mode area

    Science.gov (United States)

    Liu, Yuanye

    The on-going research and application interests with high power large-mode-area (LMA) waveguide lasers, especially in fiber geometry, at the beginning of this century drive the development of many novel waveguide designs. Index antiguiding, proposed by Siegman in 2003, is among one of them. The goal for index antiguiding is to introduce transversal modal loss with the relative simple waveguide design while maintain single transverse mode operation for good beam quality. The idea which is selectively support of fundamental mode is facilitated by involving certain level of signal regeneration inside the waveguide core. Since the modal loss is closed associated with waveguide design parameters such as core size and refractive index, the amount of gain inside the core provides active control of transverse modes inside index-antiguiding waveguide. For example, fundamental transverse mode inside such waveguide can be excited and propagate lossless when sufficient optical gain is provided. This often requires doped waveguide core and optical pumping at corresponding absorption band. However, the involvement of optical pumping also has its consequences. Phenomena such as thermal-optic effect and gain spatial hole-burning which are commonly found in bulk lasers request attention when scaling up output power with LMA index-antiguided waveguide amplifiers and resonators. In response, three key challenges of index-antiguided planar waveguide lasers, namely, guiding mechanism, power efficiency and transverse mode discrimination, are analyzed theoretically and experimentally in this dissertation. Experiments are based on two index-antiguided planar waveguide chips, whose core thickness are 220 microm and 400 microm respectively. The material of waveguide core is 1% Neodymium-doped Yttrium Aluminium garnet, or Nd:YAG while the cladding is made from Terbium Gallium garnet, or TGG. Due to the face pumping and limited pump power, it is found, with 220 microm-thick-core chip, that

  20. Laser cutting technology using water jet waveguide

    International Nuclear Information System (INIS)

    Akiba, Miyuki; Shiihara, Katsunori; Chida, Itaru

    2013-01-01

    Laser with water jet is examined to cut in-vessel structure. However, it is necessary to increase the break-up length of water jet to cut a thick plate. Therefore, the effects of the water jet parameter (water pressure, assist gas, laser power) on break-up length were investigated. It was found from observation results of water jet that the longest break-up length is about 135mm under condition of water pressure 40 MPa, laser power 30W and helium assist gas 1L/min. (author)

  1. Semiconductor ring lasers coupled by a single waveguide

    Science.gov (United States)

    Coomans, W.; Gelens, L.; Van der Sande, G.; Mezosi, G.; Sorel, M.; Danckaert, J.; Verschaffelt, G.

    2012-06-01

    We experimentally and theoretically study the characteristics of semiconductor ring lasers bidirectionally coupled by a single bus waveguide. This configuration has, e.g., been suggested for use as an optical memory and as an optical neural network motif. The main results are that the coupling can destabilize the state in which both rings lase in the same direction, and it brings to life a state with equal powers at both outputs. These are both undesirable for optical memory operation. Although the coupling between the rings is bidirectional, the destabilization occurs due to behavior similar to an optically injected laser system.

  2. Plasmonic Waveguide-Integrated Nanowire Laser

    DEFF Research Database (Denmark)

    Bermudez-Urena, Esteban; Tutuncuoglu, Gozde; Cuerda, Javier

    2017-01-01

    technologies. Despite significant advances in their fundamental aspects, the integration within scalable photonic circuitry remains challenging. Here we report on the realization of hybrid photonic devices consisting of nanowire lasers integrated with wafer-scale lithographically designed V-groove plasmonic......Next-generation optoelectronic devices and photonic circuitry will have to incorporate on-chip compatible nanolaser sources. Semiconductor nanowire lasers have emerged as strong candidates for integrated systems with applications ranging from ultrasensitive sensing to data communication...

  3. Plasmonic Waveguide-Integrated Nanowire Laser

    DEFF Research Database (Denmark)

    Bermudez-Urena, Esteban; Tutuncuoglu, Gozde; Cuerda, Javier

    2017-01-01

    Next-generation optoelectronic devices and photonic circuitry will have to incorporate on-chip compatible nanolaser sources. Semiconductor nanowire lasers have emerged as strong candidates for integrated systems with applications ranging from ultrasensitive sensing to data communication technolog......Next-generation optoelectronic devices and photonic circuitry will have to incorporate on-chip compatible nanolaser sources. Semiconductor nanowire lasers have emerged as strong candidates for integrated systems with applications ranging from ultrasensitive sensing to data communication...... technologies. Despite significant advances in their fundamental aspects, the integration within scalable photonic circuitry remains challenging. Here we report on the realization of hybrid photonic devices consisting of nanowire lasers integrated with wafer-scale lithographically designed V-groove plasmonic...

  4. Integration of quantum cascade lasers and passive waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Montoya, Juan, E-mail: juan.montoya@ll.mit.edu; Wang, Christine; Goyal, Anish; Creedon, Kevin; Connors, Michael; Daulton, Jeffrey; Donnelly, Joseph; Missaggia, Leo; Aleshire, Chris; Sanchez-Rubio, Antonio; Herzog, William [MIT Lincoln Laboratory, 244 Wood St, Lexington, Massachusetts 02420 (United States)

    2015-07-20

    We report on monolithic integration of active quantum cascade laser (QCL) materials with passive waveguides formed by using proton implantation. Proton implantation reduces the electron concentration in the QCL layers by creating deep levels that trap carriers. This strongly reduces the intersubband absorption and the free-carrier absorption in the gain region and surrounding layers, thus significantly reducing optical loss. We have measured loss as low as α = 0.33 cm{sup −1} in λ = 9.6 μm wavelength proton-implanted QCL material. We have also demonstrated lasing in active-passive integrated waveguides. This simple integration technique is anticipated to enable low-cost fabrication in infrared photonic integrated circuits in the mid-infrared (λ ∼ 3–16 μm)

  5. Integration of quantum cascade lasers and passive waveguides

    International Nuclear Information System (INIS)

    Montoya, Juan; Wang, Christine; Goyal, Anish; Creedon, Kevin; Connors, Michael; Daulton, Jeffrey; Donnelly, Joseph; Missaggia, Leo; Aleshire, Chris; Sanchez-Rubio, Antonio; Herzog, William

    2015-01-01

    We report on monolithic integration of active quantum cascade laser (QCL) materials with passive waveguides formed by using proton implantation. Proton implantation reduces the electron concentration in the QCL layers by creating deep levels that trap carriers. This strongly reduces the intersubband absorption and the free-carrier absorption in the gain region and surrounding layers, thus significantly reducing optical loss. We have measured loss as low as α = 0.33 cm −1 in λ = 9.6 μm wavelength proton-implanted QCL material. We have also demonstrated lasing in active-passive integrated waveguides. This simple integration technique is anticipated to enable low-cost fabrication in infrared photonic integrated circuits in the mid-infrared (λ ∼ 3–16 μm)

  6. SPECIAL ISSUE DEVOTED TO THE 25th ANNIVERSARY OF THE A.M. PROKHOROV GENERAL PHYSICS INSTITUTE: High-speed ablation of ultradeep channels by a phase-conjugate dynamically controlled passively Q-switched Nd:YAG laser

    Science.gov (United States)

    Basiev, T. T.; Garnov, S. V.; Klimentov, S. M.; Pivovarov, P. A.; Gavrilov, A. V.; Smetanin, S. N.; Solokhin, S. A.; Fedin, A. V.

    2007-10-01

    Parameters of high-speed ablation of ultradeep channels by controlled pulse trains from a single-mode phase-conjugate dynamic cavity Nd:YAG laser emitting 20-200-ns, 70-250-mJ pulses at a pulse repetition rate in a train of 40-250 kHz are studied. The optimal parameters of ablation are found, for which a long-lived region of a hot rarefied gas was maintained in the ultradeep channel, which suppressed the shielding action of the surface plasma. The control of the lasing process during ablation optimises not only the heating and plasma formation, but also the removal of the processed material in the pause between laser pulses. Adaptive regulation of lasing parameters during ablation made it possible to obtain ultradeep channels of length 8-27 mm and diameters 80-300 μm of the input and output holes in metals (aluminium, steel and Inconel 718 nickel superalloy) and ultrahard ceramics (Al2O3, AlN, SiC).

  7. Characterization of Bragg gratings in Al2O3 waveguides fabricated by focused ion beam milling and laser interference lithography

    NARCIS (Netherlands)

    Ay, F.; Bernhardi, Edward; Agazzi, L.; Bradley, J.; Worhoff, Kerstin; Pollnau, Markus; de Ridder, R.M.

    Optical grating cavities in Al2O3 channel waveguides were successfully defined by focused ion beam milling and laser interference lithography. Both methods are shown to be suitable for realizing resonant structures for on-chip waveguide lasers.

  8. Laser plant "Iguana" for transmyocardial revascularization based on kW-level waveguide CO2 laser

    Science.gov (United States)

    Panchenko, Vladislav Y.; Bockeria, L. A.; Berishvili, I. I.; Vasiltsov, Victor V.; Golubev, Vladimir S.; Ul'yanov, Valery A.

    2001-05-01

    For many years the Institute on Laser and Information Technologies RAN has been developing a concept of high-power industrial CO2 lasers with diffusion cooling of the working medium. The paper gives a description of the laser medical system Iguana for transmyocardial laser revascularization (TMLR) as an example of various applications of high-power waveguide CO2 lasers. The clinical results of the TMLR method application in surgical treatment are presented. The methods of determination of the time, when the laser beam passes through the demarcation line between myocardium tissue and blood, are discussed.

  9. A stable dual-wavelength Q-switch using a compact passive device containing photonics crystal fiber embedded with carbon platinum

    Science.gov (United States)

    Safaei, R.; Amiri, I. S.; Rezayi, M.; Ahmad, H.

    2018-01-01

    A compact fiber laser utilizing platinum nanoparticles doped on carbon (Pt/C) embedded in photonic crystal fiber capable of generating a stable Q-switch dual-wavelength is designed and verified. Stable Q-switch pulses, with a repetition rate of 73.6 kHz, pulse width of 1.45 µs and power of 3.8 nJ in two separated wavelengths of 1557.39 nm and 1558.86 nm at a pump power of 350 mW, have been obtained. This is a novel method for generating Q-switch dual-wavelength pulses using a well-protected component that introduces both a saturable absorber and Mach-Zehnder interferometer effects simultaneously in the laser cavity. Furthermore, to best of our knowledge, this is the first time that Pt/C nanoparticles have been used in a saturable absorber for optical pulse generation.

  10. Q-switching and mode-locking pulse generation with graphene oxide paper-based saturable absorber

    Directory of Open Access Journals (Sweden)

    Sulaiman Wadi Harun

    2015-06-01

    Full Text Available Q-switched and mode-locked erbium-doped fibre lasers (EDFLs are demonstrated by using non-conductive graphene oxide (GO paper as a saturable absorber (SA. A stable and self-starting Q-switched operation was achieved at 1534.4 nm by using a 0.8 m long erbium-doped fibre (EDF as a gain medium. The pulse repetition rate changed from 14.3 to 31.5 kHz, whereas the corresponding pulse width decreased from 32.8 to 13.8 µs as the pump power increased from 22 to 50.5 mW. A narrow spacing dual-wavelength Q-switched EDFL could also be realised by including a photonics crystal fibre and a tunable Bragg filter in the setup. It can operate at a maximum repetition rate of 31 kHz, with a pulse duration of 7.04 µs and pulse energy of 2.8 nJ. Another GOSA was used to realise mode-locked EDFL in a different cavity consisting of a 1.6 m long EDF in conjunction with 1480 nm pumping. The laser generated a soliton pulse train with a repetition rate of 15.62 MHz and pulse width of 870 fs. It is observed that the proposed fibre lasers have a low pulsing threshold pump power as well as a low damage threshold.

  11. UV laser-assisted fabrication of ridge waveguides in lithium niobate crystals

    OpenAIRE

    Sones, C.L.; Ying, C.Y.J.; Eason, R.W.; Mailis, S.; Ganguly, P.; Soergel, E.

    2010-01-01

    We present a UV laser-assisted method for the fabrication of ridge waveguides in lithium niobate. The UV laser irradiation step provides the refractive index change required for the vertical light confinement in the waveguide and also defines the ferroelectric domain pattern which produces the ridge structures after chemical etching.

  12. Infrared plasmonic nano-lasers based on Metal Insulator Metal waveguides

    NARCIS (Netherlands)

    Hill, M.T.

    2010-01-01

    We will present our latest results on metal-insulator-metal waveguide devices, in particular reducing the dimensions of devices and distributed feedback lasers. Also we will examine potential useful applications for metal nano-lasers.

  13. Concept of infrared laser particle accelerators with oversized DBR and HFB waveguides

    International Nuclear Information System (INIS)

    Arnesson, J.; Gnepf, S.; Nessi, M.; Woelfli, W.; Kneubuehl, F.K.

    1986-01-01

    We present an infrared-laser accelerator scheme which makes use of hollow oversized linear periodic and helical waveguide structures originally designed for distributed feedback (DFB) and helical feedback (HFB) lasers

  14. Fully integrated Q-switch for commercial high-power resonator with solitary XLMA-fiber

    Science.gov (United States)

    Lange, R.; Bachert, C.; Rehmann, G.; Weber, H.; Luxen, R.; Enns, H.; Schenk, M.; Hosdorf, S.; Marfels, S.; Bay, M.; Kösters, A.; Krause, V.; Giesberts, M.; Fitzau, O.; Hoffmann, H.-D.

    2018-02-01

    In surface processing applications the correlation of laser power to processing speed demands a further enhancement of the performance of short-pulsed laser sources with respect to the investment costs. The frequently applied concept of master oscillator power amplifier relies on a complex structure, parts of which are highly sensitive to back reflected amplified radiation. Aiming for a simpler, robust source using only a single ytterbium doped XLMA fiber in a q-switched resonator appears as promising design approach eliminating the need for subsequent amplification. This concept requires a high power-tolerant resonator which is provided by the multikilowatt laser platform of Laserline including directly water-cooled active fiber thermal management. Laserline GmbH and Fraunhofer Institute for Laser Technology joined their forces1 to upgrade standard high power laser sources for short-pulsed operation exceeding 1 kW of average power. Therefor a compact, modular qswitch has been developed. In this paper the implementation of a polarization independent q-switch into an off-the-shelf multi-kilowatt diodepumped continuous wave fiber source is shown. In this early step of implementation we demonstrated more than 1000 W of average power at pulse lengths below 50 ns FWHM and 7.5 mJ pulse energy. The M2 corresponds to 9.5. Reliability of the system is demonstrated based on measurements including temperature and stability records. We investigated the variation possibilities concerning pulse parameters and shape as well as upcoming challenges in power up-scaling.

  15. Low-loss optical waveguides in β-BBO crystal fabricated by femtosecond-laser writing

    Science.gov (United States)

    Li, Ziqi; Cheng, Chen; Romero, Carolina; Lu, Qingming; Vázquez de Aldana, Javier Rodríguez; Chen, Feng

    2017-11-01

    We report on the fabrication and characterization of β-BBO depressed cladding waveguides fabricated by femtosecond-laser writing with no significant changes in the waveguide lattice microstructure. The waveguiding properties and the propagation losses of the cladding structures are investigated, showing good transmission properties at wavelengths of 400 and 800 nm along TM polarization. The minimum propagation losses are measured to be as low as 0.19 dB/cm at wavelength of 800 nm. The well-preserved waveguide lattice microstructure and good guiding performances with low propagation losses suggest the potential applications of the cladding waveguides in β-BBO crystal as novel integrated photonic devices.

  16. Tubular depressed cladding waveguide laser realized in Yb: YAG by direct inscription of femtosecond laser

    International Nuclear Information System (INIS)

    Tang, Wenlong; Zhang, Wenfu; Liu, Xin; Liu, Shuang; Cheng, Guanghua; Stoian, Razvan

    2015-01-01

    We report on the fabrication of tubular depressed cladding waveguides in single crystalline Yb:YAG by the direct femtosecond laser writing technique. Full control over the confined light spatial distribution is demonstrated by the photoinscription of high index contrast waveguides with tubular configuration. Under optical pumping, highly efficient laser oscillation in depressed cladding waveguide at 1030 nm is demonstrated. The maximum output power obtained is 68 mW with a slope efficiency of 35% for an outcoupling transmission of 50%. A slope efficiency as high as 44% is realized when the coupling output ratio is 91% and a low lasing threshold of 70 mW is achieved with the output coupling mirror of 10%. (paper)

  17. Wavelength-tunable laser based on nonlinear dispersive-wave generation in a tapered optical waveguide

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a method and a wavelength tunable laser comprising a first laser source configured to emit a first optical pulse having a pump wavelength, the first optical pulse being emitted in a first longitudinal direction. Furthermore, the wavelength tunable laser comprises...... a waveguide extending in the first longitudinal direction, the waveguide having longitudinally varying phase matching conditions, the waveguide being configured to generate a second optical pulse with a centre wavelength upon receiving the first optical pulse, wherein the wavelength tunable laser...... is configured to tune the centre wavelength of the second optical pulse by varying at least one pulse property of the first optical pulse....

  18. Waveguides fabricated by femtosecond laser exploiting both depressed cladding and stress-induced guiding core.

    Science.gov (United States)

    Dong, Ming-Ming; Wang, Cheng-Wei; Wu, Zheng-Xiang; Zhang, Yang; Pan, Huai-Hai; Zhao, Quan-Zhong

    2013-07-01

    We report on the fabrication of stress-induced optical channel waveguides and waveguide splitters with laser-depressed cladding by femtosecond laser. The laser beam was focused into neodymium doped phosphate glass by an objective producing a destructive filament. By moving the sample along an enclosed routine in the horizontal plane followed by a minor descent less than the filament length in the vertical direction, a cylinder with rarified periphery and densified center region was fabricated. Lining up the segments in partially overlapping sequence enabled waveguiding therein. The refractive-index contrast, near- and far-field mode distribution and confocal microscope fluorescence image of the waveguide were obtained. 1-to-2, 1-to-3 and 1-to-4 splitters were also machined with adjustable splitting ratio. Compared with traditional femtosecond laser writing methods, waveguides prepared by this approach showed controllable mode conduction, strong field confinement, large numerical aperture, low propagation loss and intact core region.

  19. Low loss depressed cladding waveguide inscribed in YAG:Nd single crystal by femtosecond laser pulses.

    Science.gov (United States)

    Okhrimchuk, Andrey; Mezentsev, Vladimir; Shestakov, Alexander; Bennion, Ian

    2012-02-13

    A depressed cladding waveguide with record low loss of 0.12 dB/cm is inscribed in YAG:Nd(0.3at.%) crystal by femtosecond laser pulses with an elliptical beam waist. The waveguide is formed by a set of parallel tracks which constitute the depressed cladding. It is a key element for compact and efficient CW waveguide laser operating at 1064 nm and pumped by a multimode laser diode. Special attention is paid to mechanical stress resulting from the inscription process. Numerical calculation of mode distribution and propagation loss with the elasto-optical effect taken into account leads to the conclusion that the depressed cladding is a dominating factor in waveguide mode formation, while the mechanical stress only slightly distorts waveguide modes.

  20. Hybrid Coupling of Laser Light sources to Silicon (Oxy)Nitride Based Waveguides

    NARCIS (Netherlands)

    Krijger, A.J.T. de; Bekman, H.H.P.T.

    1997-01-01

    An efficient method was developed to couple a diode laser to a high contrast waveguides. The laserdiodes were mounted with sub-micron precision using a thermocompression mounting technique. An AlGaAs (λ = 850 nm) laserdiode was coupled to a SiON based slab waveguide (efficiency η EQ 25 - 30%) and to

  1. Bragg Grating Waveguide Array Ultrafast Laser Inscribed into the Cladding of a Flat Fiber

    Directory of Open Access Journals (Sweden)

    Beecher Stephen J.

    2013-11-01

    Full Text Available We report the fabrication and initial characterization of a waveguide sensor array in the cladding of a flat fiber. The sensor, designed to independently measure the strain on three Bragg grating waveguides, exploits the true three dimensional fabrication technology of ultrafast laser inscription by placing these gratings in a non-planar configuration.

  2. Light propagation studies on laser modified waveguides using scanning near-field optical microscopy

    DEFF Research Database (Denmark)

    Borrise, X.; Berini, Abadal Gabriel; Jimenez, D.

    2001-01-01

    By means of direct laser writing on Al, a new method to locally modify optical waveguides is proposed. This technique has been applied to silicon nitride waveguides, allowing modifications of the optical propagation along the guide. To study the formed structures, a scanning near-held optical mic...

  3. Cladding-like waveguide fabricated by cooperation of ultrafast laser writing and ion irradiation: characterization and laser generation.

    Science.gov (United States)

    Lv, Jinman; Shang, Zhen; Tan, Yang; Vázquez de Aldana, Javier Rodríguez; Chen, Feng

    2017-08-07

    We report the surface cladding-like waveguide fabricated by the cooperation of the ultrafast laser writing and the ion irradiation. The ultrafast laser writes tracks near the surface of the Nd:YAG crystal, constructing a semi-circle columnar structure with a decreased refractive index of - 0.00208. Then, the Nd:YAG crystal is irradiated by the Carbon ion beam, forming an enhanced-well in the semi-circle columnar with an increased refractive index of + 0.0024. Tracks and the enhanced-well consisted a surface cladding-like waveguide. Utilizing this cladding-like waveguide as the gain medium for the waveguide lasing, optimized characterizations were observed compared with the monolayer waveguide. This work demonstrates the refractive index of the Nd:YAG crystal can be well tailored by the cooperation of the ultrafast laser writing and the ion irradiation, which provides an convenient way to fabricate the complex and multilayered photonics devices.

  4. Optical study of planar waveguides based on oxidized porous silicon impregnated with laser dyes

    Energy Technology Data Exchange (ETDEWEB)

    Chouket, A. [Unite de recherche de Spectroscopie Raman, Departement de Physique, Faculte des Sciences de Tunis, Elmanar 2092, Tunis (Tunisia); Charrier, J. [Laboratoire d' Optronique CNRS-UMR FOTON 6082, Universite de Rennes 1, ENSSAT-6 rue de Kerampont, BP 80518, 22305 Lannion Cedex (France); Elhouichet, H. [Unite de recherche de Spectroscopie Raman, Departement de Physique, Faculte des Sciences de Tunis, Elmanar 2092, Tunis (Tunisia)], E-mail: habib.elhouichet@fst.rnu.tn; Oueslati, M. [Unite de recherche de Spectroscopie Raman, Departement de Physique, Faculte des Sciences de Tunis, Elmanar 2092, Tunis (Tunisia)

    2009-05-15

    Oxidized porous silicon optical planar waveguides were elaborated and impregnated with rhodamine B and rhodamine 6G. The waveguiding, absorption, and photoluminescence properties of these impregnated waveguides were studied. Successful impregnation of the structure with laser dyes is shown from photoluminescence and reflectivity measurements. Furthermore, the reflectivity spectra prove the homogenous incorporation of both dye molecules inside the pores of the matrices. The refractive indices of waveguide layers were determined before and after dye impregnation to indicate the conservation of guiding conditions. The optical losses in the visible wavelengths are studied as a function of dye concentration. The dye absorption is the main reason for these losses.

  5. Transverse Writing of Multimode Interference Waveguides inside Silica Glass by Femtosecond Laser Pulses

    International Nuclear Information System (INIS)

    Da-Yong, Liu; Yan, Li; Yan-Ping, Dou; Heng-Chang, Guo; Hong, Yang; Qi-Huang, Gong

    2008-01-01

    Multi-mode interference waveguides are fabricated inside silica glass by transverse writing geometry with femtosecond laser pulses. The influences of several writing and reading factors on the output mode are systematically studied. The experimental results of straight waveguides are in good agreement with the simulations by the beam propagation method. By integrating a straight waveguide with a bent waveguide, a 1 × 2 multi-mode splitter is formed and 2 × 3 lobes are observed in the output mode. (fundamental areas of phenomenology (including applications))

  6. Hybrid vertical-cavity laser with lateral emission into a silicon waveguide

    DEFF Research Database (Denmark)

    Park, Gyeong Cheol; Xue, Weiqi; Taghizadeh, Alireza

    2015-01-01

    into the waveguide integrated with the laser. This laser has the advantages of long-wavelength vertical-cavity surface-emitting lasers, such as low threshold and high side-mode suppression ratio, while allowing integration with silicon photonic circuits, and is fabricated using CMOS compatible processes. It has......We experimentally demonstrate an optically-pumped III-V/Si vertical-cavity laser with lateral emission into a silicon waveguide. This on-chip hybrid laser comprises a distributed Bragg reflector, a III-V active layer, and a high-contrast grating reflector, which simultaneously funnels light...

  7. Hollow core waveguide as mid-infrared laser modal beam filter

    Energy Technology Data Exchange (ETDEWEB)

    Patimisco, P.; Giglio, M.; Spagnolo, V. [Dipartimento Interateneo di Fisica, Università e Politecnico di Bari, CNR-IFN UOS BARI, Via Amendola 173, 70126 Bari (Italy); Sampaolo, A. [Dipartimento Interateneo di Fisica, Università e Politecnico di Bari, CNR-IFN UOS BARI, Via Amendola 173, 70126 Bari (Italy); Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005 (United States); Kriesel, J. M. [Opto-Knowledge Systems, Inc. (OKSI), 19805 Hamilton Ave., Torrance, California 90502-1341 (United States); Tittel, F. K. [Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005 (United States)

    2015-09-21

    A novel method for mid-IR laser beam mode cleaning employing hollow core waveguide as a modal filter element is reported. The influence of the input laser beam quality on fiber optical losses and output beam profile using a hollow core waveguide with 200 μm-bore size was investigated. Our results demonstrate that even when using a laser with a poor spatial profile, there will exist a minimum fiber length that allows transmission of only the Gaussian-like fundamental waveguide mode from the fiber, filtering out all the higher order modes. This essentially single mode output is preserved also when the waveguide is bent to a radius of curvature of 7.5 cm, which demonstrates that laser mode filtering can be realized even if a curved light path is required.

  8. Stressed waveguides with tubular depressed-cladding inscribed in phosphate glasses by femtosecond hollow laser beams.

    Science.gov (United States)

    Long, Xuewen; Bai, Jing; Zhao, Wei; Stoian, Razvan; Hui, Rongqing; Cheng, Guanghua

    2012-08-01

    We report on the single-step fabrication of stressed optical waveguides with tubular depressed-refractive-index cladding in phosphate glasses by the use of focused femtosecond hollow laser beams. Tubelike low index regions appear under direct exposure due to material rarefaction following expansion. Strained compacted zones emerged in domains neighboring the tubular track of lower refractive index, and waveguiding occurs mainly within the tube core fabricated by the engineered femtosecond laser beam. The refractive index profile of the optical waveguide was reconstructed from the measured transmitted near-field intensity.

  9. A rapid tattoo removal technique using a combination of pulsed Er:YAG and Q-Switched Nd:YAG in a split lesion protocol.

    Science.gov (United States)

    Sardana, Kabir; Ranjan, Rashmi; Kochhar, Atul M; Mahajan, Khushbu Goel; Garg, Vijay K

    2015-01-01

    Tattoo removal has evolved over the years and though Q-switched laser is the 'workhorse' laser, it invariably requires multiple sittings, which are dependent on numerous factors, including the skin colour, location of the tattoo, age of the tattoo, colour of pigment used, associated fibrosis and the kind of tattoo treated. Though ablative lasers, both pulsed CO2 and Er:YAG, have been used for recalcitrant tattoos, very few studies have been done comparing them with pigment-specific lasers. Our study was based on the premise that ablating the epidermis overlying the tattoo pigment with Er:YAG could help in gaining better access to the pigment which would enable the Q-switched laser to work effectively with less beam scattering. A study of rapid tattoo removal (RTR) technique using a combination of pulsed Er:YAG and Q-Switched Nd:YAG in a split lesion protocol. This prospective study was undertaken during 2010-13 at a laser Clinic in the Maulana Azad Medical College, New Delhi. A total of 10 patients were recruited, 5 of amateur tattoo and 5 of professional tattoo. After informed consent each tattoo was arbitrarily 'split' into two parts. One part was treated with QS Nd:YAG laser(1064 nm) and the other part with Er:YAG laser immediately followed by the QS Nd:YAG. The laser treatments were repeated at 6-week intervals until the tattoo pigment had cleared. On the combination side in subsequent sittings only the QS Nd:YAG was used, to minimize repetitive ablation. To ensure consistency in the intervention methods a trained dermatologist who was independent of the treatment delivery randomly rated 10% of the procedures. The mean improvement achieved by the Q-switched laser (2.93) was less than the combination laser (3.85) side (p = 0.001) and needed more sessions (3.8 vs. 1.6; p = 0.001). There was a statistically significant difference in the improvement on the combination side till the second session. On the combination side patients required a maximum of 2 sessions

  10. Heat accumulation during high repetition rate ultrafast laser interaction: Waveguide writing in borosilicate glass

    International Nuclear Information System (INIS)

    Zhang, Haibin; Eaton, Shane M; Li, Jianzhao; Herman, Peter R

    2007-01-01

    During high repetition rate (>200 kHz) ultrafast laser waveguide writing, visible heat modified zones surrounding the formed waveguide occur as a result of heat accumulation. The radii of the heat-modified zones increase with the laser net fluence, and were found to correlate with the formation of low-loss and cylindrically symmetric optical waveguides. A numerical thermal model based on the finite difference method is applied here to account for cumulative heating and diffusion effects. The model successfully shows that heat propagation and accumulation accurately predict the radius of the 'heat modified' zones observed in borosilicate glass waveguides formed across a wide range of laser exposure conditions. Such modelling promises better control of thermal effects for optimizing the fabrication and performance of three-dimensional optical devices in transparent materials

  11. Inscription of type I and depressed cladding waveguides in lithium niobate using a femtosecond laser.

    Science.gov (United States)

    Bhardwaj, S; Mittholiya, K; Bhatnagar, A; Bernard, R; Dharmadhikari, J A; Mathur, D; Dharmadhikari, A K

    2017-07-10

    We describe two types of waveguides (type I and depressed cladding) inscribed in lithium niobate using a variable repetition rate (200 kHz-25 MHz), 270 fs duration fiber laser. The type I modification-based waveguides have propagation losses in the range from 1.2 to 10 dB/cm at 1550 nm, depending on experimental parameters. These waveguides are not permanent; they deteriorate over time. Such deterioration of waveguides can be slowed down from 30 days to 100 days by pre-annealing the samples and by writing at a 720 kHz laser repetition rate. The propagation losses measured at 1550 nm show significant improvement for pre-annealed samples. The depressed cladding-inscribed waveguides are permanent, but the propagation loss depends on the number of damage tracks. A track separation of ∼1  μm between adjacent damage tracks yields the lowest propagation loss of 0.5 dB/cm at 1550 nm for a 40 μm diameter waveguide. We observe multimode guidance for sizes in the range of 20-80 μm in these waveguide structures at 1550 nm. Their crystalline nature is found to remain intact, as inferred from second-harmonic generation within the waveguide region.

  12. Optical lattice-like cladding waveguides by direct laser writing: fabrication, luminescence, and lasing.

    Science.gov (United States)

    Nie, Weijie; He, Ruiyun; Cheng, Chen; Rocha, Uéslen; Rodríguez Vázquez de Aldana, Javier; Jaque, Daniel; Chen, Feng

    2016-05-15

    We report on the fabrication of optical lattice-like waveguide structures in an Nd:YAP laser crystal by using direct femtosecond laser writing. With periodically arrayed laser-induced tracks, the waveguiding cores can be located in either the regions between the neighbored tracks or the central zone surrounded by a number of tracks as outer cladding. The polarization of the femtosecond laser pulses for the inscription has been found to play a critical role in the anisotropic guiding behaviors of the structures. The confocal photoluminescence investigations reveal different stress-induced modifications of the structures inscribed by different polarization of the femtosecond laser beam, which are considered to be responsible for the refractive index changes of the structures. Under optical pump at 808 nm, efficient waveguide lasing at ∼1  μm wavelength has been realized from the optical lattice-like structure, which exhibits potential applications as novel miniature light sources.

  13. Beam shaping of laser diode radiation by waveguides with arbitrary cladding geometry written with fs-laser radiation.

    Science.gov (United States)

    Beckmann, Dennis; Schnitzler, Daniel; Schaefer, Dagmar; Gottmann, Jens; Kelbassa, Ingomar

    2011-12-05

    Waveguides with arbitrary cross sections are written in the volume of Al(2)O(3)-crystals using tightly focused femtosecond laser radiation. Utilizing a scanning system with large numerical aperture, complex cladding geometries are realized with a precision around 0.5 µm and a scanning speed up to 100 mm/s. Individual beam and mode shaping of laser diode radiation is demonstrated by varying the design of the waveguide cladding. The influence of the writing parameters on the waveguide properties are investigated resulting in a numerical aperture of the waveguides in the range of 0.1. This direct laser writing technique enables optical devices which could possibly replace bulky beam shaping setups with an integrated solution.

  14. A microwave FEL [free electron laser] code using waveguide modes

    International Nuclear Information System (INIS)

    Byers, J.A.; Cohen, R.H.

    1987-08-01

    A free electron laser code, GFEL, is being developed for application to the LLNL tokamak current drive experiment, MTX. This single frequency code solves for the slowly varying complex field amplitude using the usual wiggler-averaged equations of existing codes, in particular FRED, except that it describes the fields by a 2D expansion in the rectangular waveguide modes, using coupling coefficients similar to those developed by Wurtele, which include effects of spatial variations in the fields seen by the wiggler motion of the particles. Our coefficients differ from those of Wurtele in two respects. First, we have found a missing √2γ/a/sub w/ factor in his C/sub z/; when corrected this increases the effect of the E/sub z/ field component and this in turn reduces the amplitude of the TM mode. Second, we have consistently retained all terms of second order in the wiggle amplitude. Both corrections are necessary for accurate computation. GFEL has the capability of following the TE/sub 0n/ and TE(M)/sub m1/ modes simultaneously. GFEL produces results nearly identical to those from FRED if the coupling coefficients are adjusted to equal those implied by the algorithm in FRED. Normally, the two codes produce results that are similar but different in detail due to the different treatment of modes higher than TE/sub 01/. 5 refs., 2 figs., 1 tab

  15. Selection of transverse modes in laser cavities containing waveguides and open parts

    International Nuclear Information System (INIS)

    Gurin, O V; Degtyarev, A V; Maslov, Vyacheslav A; Svich, V A; Tkachenko, V M; Topkov, A N

    2001-01-01

    The transverse modes of a submillimetre laser cavity that contains waveguides and open parts were studied theoretically and experimentally with the purpose of finding methods for mode selection. Two methods based on the filtering of the Fourier spectra of the waveguide modes and the use of their interference were substantiated numerically and realised in experiment. Special attention was paid to the mode selection in tunable lasers. Scaling laws allowing one to use the obtained results in a wide range of the cavity parameters and wavelengths are presented. (laser applications and other topics in quantum electronics)

  16. Femtosecond-laser inscribed double-cladding waveguides in Nd:YAG crystal: a promising prototype for integrated lasers.

    Science.gov (United States)

    Liu, Hongliang; Chen, Feng; Vázquez de Aldana, Javier R; Jaque, D

    2013-09-01

    We report on the design and implementation of a prototype of optical waveguides fabricated in Nd:YAG crystals by using femtosecond-laser irradiation. In this prototype, two concentric tubular structures with nearly circular cross sections of different diameters have been inscribed in the Nd:YAG crystals, generating double-cladding waveguides. Under 808 nm optical pumping, waveguide lasers have been realized in the double-cladding structures. Compared with single-cladding waveguides, the concentric tubular structures, benefiting from the large pump area of the outermost cladding, possess both superior laser performance and nearly single-mode beam profile in the inner cladding. Double-cladding waveguides of the same size were fabricated and coated by a thin optical film, and a maximum output power of 384 mW and a slope efficiency of 46.1% were obtained. Since the large diameters of the outer claddings are comparable with those of the optical fibers, this prototype paves a way to construct an integrated single-mode laser system with a direct fiber-waveguide configuration.

  17. Dramatic enhancement of XUV laser output using a multi-mode, gas-filled capillary waveguide

    Czech Academy of Sciences Publication Activity Database

    Mocek, Tomáš; McKenna, C.M.; Cros, B.; Sebban, S.; Spence, D.J.; Maynard, G.; Bettaibi, I.; Vorontsov, V.; Gonsavles, A.J.; Hooker, S.M.

    2005-01-01

    Roč. 71, 01 (2005), 013804/1-013804/5 ISSN 1050-2947 Grant - others:EU(XE) HPRI-1999-CT-00086; EU(XE) HPMF-CT-2002-01554 Institutional research plan: CEZ:AV0Z10100523 Keywords : waveguiding * x-ray laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.997, year: 2005

  18. On-chip microparticle detection and sizing using a dual-wavelength waveguide laser

    NARCIS (Netherlands)

    Bernhardi, Edward H.; van der Werf, Kees O; Hollink, Anton J F; Worhoff, Kerstin; De Ridder, Rene M.; Subramaniam, Vinod; Pollnau, Markus

    2013-01-01

    An integrated intra-laser-cavity microparticle sensor based on a dual-phase-shift, dual-wavelength distributed-feedback channel waveguide laser in Al2O3:Yb3+ is presented. Real-time detection and accurate size measurement of single microparticles with diameters ranging between 1 μm and 20 μm are

  19. On-chip microparticle detection and sizing using a dual-wavelength waveguide laser

    NARCIS (Netherlands)

    Bernhardi, Edward; van der Werf, Kees; Hollink, Anton; Worhoff, Kerstin; de Ridder, R.M.; Subramaniam, Vinod; Pollnau, Markus

    An integrated intra-laser-cavity microparticle sensor based on a dual-phase-shift, dual-wavelength distributed-feedback channel waveguide laser in ytterbium-doped aluminium oxide is presented. Single micro-particles with diameters ranging between 1 μm and 20 μm are detected.

  20. Integration of a terahertz quantum cascade laser with a hollow waveguide

    Science.gov (United States)

    Wanke, Michael C [Albuquerque, NM; Nordquist, Christopher D [Albuquerque, NM

    2012-07-03

    The present invention is directed to the integration of a quantum cascade laser with a hollow waveguide on a chip to improve both the beam pattern and manufacturability. By coupling the QCL output into a single-mode rectangular waveguide the radiation mode structure can be known and the propagation, manipulation, and broadcast of the QCL radiation can then be entirely controlled by well-established rectangular waveguide techniques. By controlling the impedance of the interface, enhanced functions, such as creating amplifiers, efficient coupling to external cavities, and increasing power output from metal-metal THz QCLs, are also enabled.

  1. Optical Cladding Waveguides in Dielectric Crystals Produced by Femtosecond Laser Inscription

    Directory of Open Access Journals (Sweden)

    Chen Feng

    2013-11-01

    Full Text Available In this work, the recent progress of our research on optical cladding waveguides in dielectric crystals produced by femtosecond laser inscription has been overviewed. With different scales at cross sections, the cladding waveguides support guidance from single mode to highly multi-modes, and work for wavelength till mid-infrared regimes. Applications of the fabricated cladding structures as new integrated light sources are introduced.

  2. Diffusion-cooled high-power single-mode waveguide CO2 laser for transmyocardial revascularization

    Science.gov (United States)

    Berishvili, I. I.; Bockeria, L. A.; Egorov, E. N.; Golubev, Vladimir S.; Galushkin, Michail G.; Kheliminsky, A. A.; Panchenko, Vladislav Y.; Roshin, A. P.; Sigaev, I. Y.; Vachromeeva, M. N.; Vasiltsov, Victor V.; Yoshina, V. I.; Zabelin, Alexandre M.; Zelenov, Evgenii V.

    1999-01-01

    The paper presents the results on investigations and development of multichannel waveguide CO2 laser with diffusion cooling of active medium excited by discharge of audio-frequency alternating current. The description of high-power single-mode CO2 laser with average beam power up to 1 kW is presented. The result of measurement of the laser basic parameters are offered, as well as the outcomes of performances of the laser head with long active zone, operating in waveguide mode. As an example of application of these laser, various capabilities a description of the developed medical system 'Genom' used in the transmyocardial laser revascularization (TMLR) procedure and clinical results of the possibilities of the TMLR in the surgical treatment are presented.

  3. Specific features of waveguide recombination in laser structures with asymmetric barrier layers

    Energy Technology Data Exchange (ETDEWEB)

    Polubavkina, Yu. S., E-mail: polubavkina@mail.ru; Zubov, F. I.; Moiseev, E. I.; Kryzhanovskaya, N. V.; Maximov, M. V. [Russian Academy of Sciences, St. Petersburg National Research Academic University (Russian Federation); Semenova, E. S.; Yvind, K. [Technical University of Denmark, DTU Fotonik (Denmark); Asryan, L. V. [Virginia Polytechnic Institute and State University (United States); Zhukov, A. E. [Russian Academy of Sciences, St. Petersburg National Research Academic University (Russian Federation)

    2017-02-15

    The spatial distribution of the intensity of the emission caused by recombination appearing at a high injection level (up to 30 kA/cm{sup 2}) in the waveguide layer of a GaAs/AlGaAs laser structure with GaInP and AlGaInAs asymmetric barrier layers is studied by means of near-field scanning optical microscopy. It is found that the waveguide luminescence in such a laser, which is on the whole less intense as compared to that observed in a similar laser without asymmetric barriers, is non-uniformly distributed in the waveguide, so that the distribution maximum is shifted closer to the p-type cladding layer. This can be attributed to the ability of the GaInP barrier adjoining the quantum well on the side of the n-type cladding layer to suppress the hole transport.

  4. Specific features of waveguide recombination in laser structures with asymmetric barrier layers

    DEFF Research Database (Denmark)

    Polubavkina, Yu; Zubov, F. I.; Moiseev, E.

    2017-01-01

    microscopy. It is found that the waveguide luminescence in such a laser, which is on the whole less intense as compared to that observed in a similar laser without asymmetric barriers, is non-uniformly distributed in the waveguide, so that the distribution maximum is shifted closer to the p-type cladding......The spatial distribution of the intensity of the emission caused by recombination appearing at a high injection level (up to 30 kA/cm2) in the waveguide layer of a GaAs/AlGaAs laser structure with GaInP and AlGaInAs asymmetric barrier layers is studied by means of near-field scanning optical...... layer. This can be attributed to the ability of the GaInP barrier adjoining the quantum well on the side of the n-type cladding layer to suppress the hole transport....

  5. Femtosecond laser-written double line waveguides in germanate and tellurite glasses

    Science.gov (United States)

    S. da Silva, Diego; Wetter, Niklaus U.; de Rossi, Wagner; Samad, Ricardo E.; Kassab, Luciana R. P.

    2018-02-01

    The authors report the fabrication and characterization of passive waveguides in GeO2-PbO and TeO2-ZnO glasses written with a femtosecond laser delivering pulses with 3μJ, 30μJ and 80fs at 4kHz repetition rate. Permanent refractive index change at the focus of the laser beam was obtained and waveguides were formed by two closely spaced laser written lines, where the light guiding occurs between them. The refractive index change at 632 nm is around 10-4 . The value of the propagation losses was around 2.0 dB/cm. The output mode profiles indicate multimodal guiding behavior. Raman measurements show structural modification of the glassy network. The results show that these materials are potential candidates for passive waveguides applications as low-loss optical components.

  6. Coherent beam combination of fiber lasers with a strongly confined waveguide: numerical model.

    Science.gov (United States)

    Tao, Rumao; Si, Lei; Ma, Yanxing; Zhou, Pu; Liu, Zejin

    2012-08-20

    Self-imaging properties of fiber lasers in a strongly confined waveguide (SCW) and their application in coherent beam combination (CBC) are studied theoretically. Analytical formulas are derived for the positions, amplitudes, and phases of the N images at the end of an SCW, which is important for quantitative analysis of waveguide CBC. The formulas are verified with experimental results and numerical simulation of a finite difference beam propagation method (BPM). The error of our analytical formulas is less than 6%, which can be reduced to less than 1.5% with Goos-Hahnchen penetration depth considered. Based on the theoretical model and BPM, we studied the combination of two laser beams based on an SCW. The effects of the waveguide refractive index and Gaussian beam waist are studied. We also simulated the CBC of nine and 16 fiber lasers, and a single beam without side lobes was achieved.

  7. Production and characterization of femtosecond laser-written double line waveguides in heavy metal oxide glasses

    Science.gov (United States)

    da Silva, Diego Silvério; Wetter, Niklaus Ursus; de Rossi, Wagner; Kassab, Luciana Reyes Pires; Samad, Ricardo Elgul

    2018-01-01

    We report the fabrication and characterization of double line waveguides directly written in tellurite and germanate glasses using a femtosecond laser delivering 30 μJ, 80 fs pulses at 4 kHz repetition rate. The double line waveguides produced presented internal losses inferior to 2.0 dB/cm. The output mode profile and the M2 measurements indicate multimodal guiding behavior. A better beam quality for the GeO2 - PbO waveguide was observed when compared with TeO2 - ZnO glass. Raman spectroscopy of the waveguides showed structural modification of the glassy network and indicates that a negative refractive index modification occurs at the focus of the laser beam, therefore allowing for light guiding in between two closely spaced laser written lines. The refractive index change at 632 nm is around 10-4, and the structural changes in the laser focal region of the writing, evaluated by Raman spectroscopy, corroborated our findings that these materials are potential candidates for optical waveguides and passive components. To the best of our knowledge, the two double line configuration demonstrated in the present work was not reported before for germanate or tellurite glasses.

  8. Propagation of a laser beam in a time-varying waveguide. [plasma heating for controlled fusion

    Science.gov (United States)

    Chapman, J. M.; Kevorkian, J.

    1978-01-01

    The propagation of an axisymmetric laser beam in a plasma column having a radially parabolic electron density distribution is reported. For the case of an axially uniform waveguide it is found that the basic characteristics of alternating focusing and defocusing beams are maintained. However, the intensity distribution is changed at the foci and outer-beam regions. The features of paraxial beam propagation are discussed with reference to axially varying waveguides. Laser plasma coupling is considered noting the case where laser heating produces a density distribution radially parabolic near the axis and the energy absorbed over the focal length of the plasma is small. It is found that: (1) beam-propagation stability is governed by the relative magnitude of the density fluctuations existing in the axial variation of the waveguides due to laser heating, and (2) for beam propagation in a time-varying waveguide, the global instability of the propagation is a function of the initial fluctuation growth rate as compared to the initial time rate of change in the radial curvature of the waveguide.

  9. Propagation of a laser beam in a time-varying waveguide

    International Nuclear Information System (INIS)

    Chapman, J.M.; Kevorkian, J.

    1978-01-01

    The propagation of an axisymmetric laser beam in a plasma column having a radially parabolic electron density distribution is examined. First, an extended paraxial procedure is developed for the case of an axially uniform waveguide. It is shown that the essential feature of an alternate focusing and defocusing beam is retained, but that the intensity distribution is cumulatively modified at the foci and at the outer portions of the beam as compared to that of the paraxial case. Second, some general features of paraxial beam propagation are examined for the case of axially varying waveguides. Finally, laser plasma coupling is examined for the case when laser heating generates a density distribution that is radially parabolic near the axis and when the energy absorbed over a focal length of a plasma lens is small. It is shown that stable or unstable beam propagation depends upon the relative magnitude of the density fluctuations which exist in the axial variation of the waveguides as a result of laser heating. When the fluctuations are small, the propagation is stable, and a simple algebraic expression is obtained which relates the beam diameter to the axially slow averaged variation in the waveguide. When the fluctuations are large, the propagation stability can be determined only by consistently combining plasma dynamics and beam propagation to interrelate the axial variation of the beam to that of the waveguide. In this case of beam propagation in a time-varying waveguide, it is shown that the global stability of the propagation depends upon the initial fluctuation growth rate compared to the initial time rate of change in the radial curvature of the waveguide

  10. Development of a high power HCN waveguide laser for plasma diagnostic

    International Nuclear Information System (INIS)

    Deng Zhongchao; Zhou Yan; Tang Yiwu; Yi Jiang; Gao Bingyi; Tian Chongli

    2007-06-01

    Both design and development of a high power cw HCN waveguide laser is described for multichannel FIR laser interferometer on the HL-2A divertor tokamak. The geometry parameters of stracture of the HCN laser are calculated according to scaling laws for cw 337 μm HCN waveguide laser offered by P. Belland et al. The designed value of output power of the laser that is more than 400 mW with discharge length of 5.6 m and 6.3 cm inner diameter of tube have been chosen in case of external loss of the cavity of 2%. At the same time, in order to get a laser system of stable output both of configuration and operating condition is discussed. In developed laser a hot LaB 6 cathode is employed to en- sure a stable discharge, the cavity mirrors are spaced using four invar rod of φ25 mm in diameter and an structure of adjusting machine for axially movable flat mirror in cavity has been also designed, and that it can be taken down many times without badly destroying alignment of the cavity etc.. A suit of pipes sys- tem of cw HCN laser is schemed out so that some experiments of operating parameter optimization can be done. The results of primary test of operating waveguide HCN laser are briefly showed. (authors)

  11. Low-Loss Hollow Waveguide Fibers for Mid-Infrared Quantum Cascade Laser Sensing Applications

    Directory of Open Access Journals (Sweden)

    James A. Harrington

    2013-01-01

    Full Text Available We report on single mode optical transmission of hollow core glass waveguides (HWG coupled with an external cavity mid-IR quantum cascade lasers (QCLs. The QCL mode results perfectly matched to the hybrid HE11 waveguide mode and the higher losses TE-like modes have efficiently suppressed by the deposited inner dielectric coating. Optical losses down to 0.44 dB/m and output beam divergence of ~5 mrad were measured. Using a HGW fiber with internal core size of 300 µm we obtained single mode laser transmission at 10.54 µm and successful employed it in a quartz enhanced photoacoustic gas sensor setup.

  12. UV waveguides light fabricated in fluoropolymer CYTOP by femtosecond laser direct writing.

    Science.gov (United States)

    Hanada, Yasutaka; Sugioka, Koji; Midorikawa, Katsumi

    2010-01-18

    We have fabricated optical waveguides inside the UV-transparent polymer, CYTOP, by femtosecond laser direct writing for propagating UV light in biochip applications. Femtosecond laser irradiation is estimated to increase the refractive index of CYTOP by 1.7 x 10(-3) due to partial bond breaking in CYTOP. The waveguide in CYTOP has propagation losses of 0.49, 0.77, and 0.91 dB/cm at wavelengths of 632.8, 355, and 266 nm, respectively.

  13. On Surface Losses in Direct Metal Laser Sintering Printed Millimeter and Submillimeter Waveguides

    Science.gov (United States)

    Holmberg, Max; Dancila, Dragos; Rydberg, Anders; Hjörvarsson, Björgvin; Jansson, Ulf; Marattukalam, Jithin James; Johansson, Niklas; Andersson, Joakim

    2018-06-01

    Different lengths of WR3 (220-330 GHz) and WR10 (75-110 GHz) waveguides are fabricated through direct metal laser sintering (DMLS). The losses in these waveguides are measured and modelled using the Huray surface roughness model. The losses in WR3 are around 0.3 dB/mm and in WR10 0.05 dB/mm. The Huray equation model is accounting relatively good for the attenuation in the WR10 waveguide but deviates more in the WR3 waveguide. The model is compared to finite element simulations of the losses assuming an approximate surface structure similar to the resulting one from the DMLS process.

  14. Absorption Spectroscopy in Hollow-Glass Waveguides Using Infrared Diode Lasers[4817-25

    International Nuclear Information System (INIS)

    Blake, Thomas A.; Kelly, James F.; Stewart, Timothy L.; Hartman, John S.; Sharpe, Steven W.; Sams, Robert L.; Alan Fried

    2002-01-01

    Near- and mid-infrared diode lasers combined with flexible, hollow waveguides hold the promise of light weight, field portable, fast response gas sensors. The advantages of using the waveguides compared to White or Herriott multireflection cells include a small gas volume, a high photon fill factor in the waveguide, which increases molecule-light interactions, and reduction or elimination of optical fringing, which usually sets the practical limit of detectivity in absorption spectroscopy. Though hollow waveguides have been commercially available for several years, relatively few results have been reported in the literature. We present here results from our laboratory where we have injected infrared laser light into straight and coiled lengths of hollow waveguides and performed direct and wavelength modulated absorption spectroscopy on nitrous oxide, ethylene, and nitric oxide. Using a 1 mm bore, 3 meter long coiled waveguide coated for the near infrared, nitrous oxide transitions near 6595 cm-1 were observed under flowing conditions. Signal-to-noise ratios on the order of 1500:1 with RMS noise equal to 2 X 10-5 were measured. In the mid-infrared light from either a 10.1 or 5.3 micron lead salt diode laser was injected into a three meter length of 1 mm bore hollow waveguide coated for the mid-infrared. The waveguide was coiled with one loop at a diameter of 52 cm. Ethylene transitions were observed in the vicinity of 985 cm-1 with a static fill of 0.2 Torr of pure ethylene in the waveguide and nitric oxide transitions were observed in the vicinity of 1906 cm-1 using either a flow or a static fill of 1 ppm NO in nitrogen. In direct absorption the NO transitions are observed to have a signal-to-noise of approximately 5:1 for transitions with absorbances on the order of 10-3. Using wavelength modulated techniques the signal-to-noise ratio improves at least an order of magnitude. These encouraging results indicate that waveguides can be used for in situ gas monitoring

  15. Integration of Quantum Cascade Lasers and Passive Waveguides

    Science.gov (United States)

    2015-06-01

    convenience, we can de - fine an effective mirror loss eαmLA = R referenced to the active region such that αm = ln(R) LA . This definition al- lows us to...the waveguide loss. The current density threshold de - pendence in a QCL may be expressed in terms of a mirror loss αm and waveguide loss αw as in Jth...M. Licht - ensteiger, C. Gatos, and H. Gatos, J. Appl. Phys. 51, 2659 (1980). 15O. Kim and W. Bonner, J. Electron. Mater. 12, 827 (1983). 16J

  16. Excitation of transversely excited CO2 waveguide lasers

    International Nuclear Information System (INIS)

    Wood II, O.R.; Smith, P.W.; Adams, C.R.; Maloney, P.J.

    1975-01-01

    Using a preionization scheme based on the Malter effect, small-signal gains >5%/cm at 10.6 μm have been produced in a 1-mm 2 -cross-section waveguide CO 2 amplifier at total operating pressures of 100--760 Torr. Comparisons are made between this preionization scheme and those using electron beams

  17. Optical spectroscopy in channel waveguides made in Nd:YAG crystals by femtosecond laser writing

    International Nuclear Information System (INIS)

    Torchia, G.A.; Mendez, C.; Roso, L.; Tocho, J.O.

    2008-01-01

    In this work, we present an optical characterization of channel waveguides fabricated by means of femtosecond laser writing on Nd:YAG substrates. These guiding structures show a refractive index increment of about 1x10 -3 which allows TE propagation. By pumping with a CW solid-state laser at 532 nm reaching the 2 G 9/2 and 4 G 7/2 manifolds of Nd 3+ ions, we have explored the emission band corresponding to 4 F 3/2 → 4 I 9/2 optical transitions (peaked at 890 nm). From data, we have found that emission showed similar characteristics for waveguide and bulk. On the other hand, the lifetime corresponding to the 4 F 3/2 metaestable level was determined to be 240 μs for bulk and waveguide. Summarizing, we have made suitable channel waveguides in Nd:YAG crystals, by fs interaction, with similar spectroscopic properties to those of the bulk, a fact that boosters the photonics application of these devices. For the first time to our knowledge, a direct index increment waveguide made by interaction with ultra-short intense pulses in YAG crystals has been performed. This fabrication procedure can be an efficient tool to make several optical circuits in active materials by means of the one-step, fast and low-cost processing

  18. Emission characteristics of laser and superluminescent diodes with a gradient-index waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Bazarov, A.E.; Garmash, I.A.; Goldobin, I.S.; Eliukhin, V.A.; Pak, G.T.

    1987-05-01

    A study is made of the emission characteristics of laser and superluminescent diodes with gradient-index waveguides based on Al(x)Ga(1-x)As solid solutions, operating in the CW mode at room temperature. The coupling coefficients for a single-mode fiber are 25 and 18 percent for laser and superluminescent diodes, respectively, when an interface device consisting of three microlenses is used. 6 references.

  19. Laser acceleration in vacuum with an open iris-loaded waveguide

    International Nuclear Information System (INIS)

    Xie, Ming

    1997-05-01

    An open iris-loaded waveguide structure is considered for laser acceleration of highly relativistic particle in vacuum. Complete characterization of all eigenmodes are given in analytical form for the structure. In particular the dominant radially polarized TM mode is evaluated in detail for laser acceleration. The entire parameter space is searched and it is found that below the laser damage threshold of the structure an acceleration gradient around 1 GV/m can be obtained over a phase slippage length of 10s of cm with TWs laser in the wavelength range from 1 to 10 μm

  20. Creating large second-order optical nonlinearity in optical waveguides written by femtosecond laser pulses in boro-aluminosilicate glass

    Science.gov (United States)

    An, Hong-Lin; Arriola, Alexander; Gross, Simon; Fuerbach, Alexander; Withford, Michael J.; Fleming, Simon

    2014-01-01

    The thermal poling technique was applied to optical waveguides embedded in a commercial boro-aluminosilicate glass, resulting in high levels of induced second-order optical nonlinearity. The waveguides were fabricated using the femtosecond laser direct-write technique, and thermally poled samples were characterized with second harmonic optical microscopy to reveal the distribution profile of the induced nonlinearity. It was found that, in contrast to fused silica, the presence of waveguides in boro-aluminosilicate glass led to an enhancement of the creation of the second-order nonlinearity, which is larger in the laser written waveguiding regions when compared to the un-modified substrate. The magnitude of the nonlinear coefficient d33 achieved in the core of the laser-written waveguides, up to 0.2 pm/V, was comparable to that in thermally poled fused silica, enabling the realization of compact integrated electro-optic devices in boro-aluminosilicate glasses.

  1. Linearly polarized intracavity passive Q-switched Yb-doped ...

    Indian Academy of Sciences (India)

    2014-02-14

    Feb 14, 2014 ... ytterbium-doped photonic crystal fibre laser with a Cr4+:YAG crystal ... average output power of 9.4 W with pulse duration of 64 ns and ... applications of nonlinear frequency shifting like frequency doubling and optical paramet-.

  2. Spontaneous emission and gain in a waveguide free-electron laser

    International Nuclear Information System (INIS)

    Golightly, W.J.; Ride, S.K.

    1991-01-01

    A free-electron laser enclosed in a waveguide of narrowly spaced parallel plates has been proposed as a compact, coherent source of far-infrared radiation. In this paper, the spontaneous emission and small-signal gain of such a device are analyzed. Maxwell's equations are solved for the fields of a relativistic electron beam passing through a linearly polarized undulator in the presence of a parallel-plane waveguide. The radiation intensity is resolved into its component waveguide modes for the fundamental frequency and for all harmonics. The intensity profile in a given harmonic mode is altered significantly when a parameter involving the undulator period, beam energy, and transverse dimension of the guide is such that the radiation group velocity is close to the electrons' axial velocity. The small-signal gain in the waveguide free-electron laser is calculated and related to the spontaneous emission. Near zero slip, the gain curve is significantly different from that of a free-space free-electron laser with the same parameters

  3. Single-step fabrication of stressed waveguides with tubular depressed-cladding in phosphate glasses using ultrafast vortex laser beams

    Directory of Open Access Journals (Sweden)

    Cheng Guanghua

    2013-11-01

    Full Text Available We report on the fabrication of the stressed optical waveguide with tubular depressed-refractive-index cladding in phosphate glasses by use of femtosecond vortex beam. Strained regions were emerged in domains surrounding the tubular track. Waveguiding occurs mainly within the tube induced by femtosecond laser.

  4. Broadband single-transverse-mode fluorescence sources based on ribs fabricated in pulsed laser deposited Ti: sapphire waveguides

    NARCIS (Netherlands)

    Grivas, C.; May-Smith, T.C.; Shepherd, D.P.; Eason, R.W.; Pollnau, Markus; Jelinek, M.

    2004-01-01

    Active rib waveguides with depths and widths varying from 3 to 5 μm and from 9 to 24 μm, respectively, have been structured by $Ar^{+}$-beam etching in pulsed laser deposited Ti:sapphire layers. Losses in the channel structures were essentially at the same levels as the unstructured planar waveguide

  5. Direct acceleration of electrons by a CO2 laser in a curved plasma waveguide

    CERN Document Server

    Yi, Longqing; Shen, Baifei

    2016-01-01

    Laser plasma interaction with micro-engineered targets at relativistic intensities has been greatly promoted by recent progress in the high contrast lasers and the manufacture of advanced micro- and nano-structures. This opens new possibilities for the physics of laser-matter interaction. Here we propose a novel approach that leverages the advantages of high-pressure CO 2 laser, laser-waveguide interaction, as well as micro-engineered plasma structure to accelerate electrons to peak energy greater than 1 GeV with narrow slice energy spread (~1%) and high overall efficiency. The acceleration gradient is 26 GV/m for a 1.3 TW CO2 laser system. The micro-bunching of a long electron beam leads to the generation of a chain of ultrashort electron bunches with the duration roughly equal to half-laser-cycle. These results open a way for developing a compact and economic electron source for diverse applications.

  6. 11-GHz waveguide Nd:YAG laser CW mode-locked with single-layer graphene.

    Science.gov (United States)

    Okhrimchuk, Andrey G; Obraztsov, Petr A

    2015-06-08

    We report stable, passive, continuous-wave (CW) mode-locking of a compact diode-pumped waveguide Nd:YAG laser with a single-layer graphene saturable absorber. The depressed cladding waveguide in the Nd:YAG crystal is fabricated with an ultrafast laser inscription method. The saturable absorber is formed by direct deposition of CVD single-layer graphene on the output coupler. The few millimeter-long cavity provides generation of 16-ps pulses with repetition rates in the GHz range (up to 11.3 GHz) and 12 mW average power. Stable CW mode-locking operation is achieved by controlling the group delay dispersion in the laser cavity with a Gires-Tournois interferometer.

  7. Heuristic modelling of laser written mid-infrared LiNbO3 stressed-cladding waveguides.

    Science.gov (United States)

    Nguyen, Huu-Dat; Ródenas, Airán; Vázquez de Aldana, Javier R; Martínez, Javier; Chen, Feng; Aguiló, Magdalena; Pujol, Maria Cinta; Díaz, Francesc

    2016-04-04

    Mid-infrared lithium niobate cladding waveguides have great potential in low-loss on-chip non-linear optical instruments such as mid-infrared spectrometers and frequency converters, but their three-dimensional femtosecond-laser fabrication is currently not well understood due to the complex interplay between achievable depressed index values and the stress-optic refractive index changes arising as a function of both laser fabrication parameters, and cladding arrangement. Moreover, both the stress-field anisotropy and the asymmetric shape of low-index tracks yield highly birefringent waveguides not useful for most applications where controlling and manipulating the polarization state of a light beam is crucial. To achieve true high performance devices a fundamental understanding on how these waveguides behave and how they can be ultimately optimized is required. In this work we employ a heuristic modelling approach based on the use of standard optical characterization data along with standard computational numerical methods to obtain a satisfactory approximate solution to the problem of designing realistic laser-written circuit building-blocks, such as straight waveguides, bends and evanescent splitters. We infer basic waveguide design parameters such as the complex index of refraction of laser-written tracks at 3.68 µm mid-infrared wavelengths, as well as the cross-sectional stress-optic index maps, obtaining an overall waveguide simulation that closely matches the measured mid-infrared waveguide properties in terms of anisotropy, mode field distributions and propagation losses. We then explore experimentally feasible waveguide designs in the search of a single-mode low-loss behaviour for both ordinary and extraordinary polarizations. We evaluate the overall losses of s-bend components unveiling the expected radiation bend losses of this type of waveguides, and finally showcase a prototype design of a low-loss evanescent splitter. Developing a realistic waveguide

  8. Improved Laser performance through Planar Waveguide Technology Development

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a laser technology development to improve efficiency and performance for a variety of science applications including: Lunar Ice, 2-Step Laser Tandem Mass...

  9. Development of a diamond waveguide sensor for sensitive protein analysis using IR quantum cascade lasers

    Science.gov (United States)

    Piron, P.; Vargas Catalan, E.; Haas, J.; Österlund, L.; Nikolajeff, F.; Andersson, P. O.; Bergström, J.; Mizaikoff, B.; Karlsson, M.

    2018-02-01

    Microfabricated diamond waveguides, between 5 and 20 μm thick, manufactured by chemical vapor deposition of diamond, followed by standard lithographic techniques and inductively coupled plasma etching of diamond, are used as bio-chemical sensors in the mid infrared domain: 5-11 μm. Infrared light, emitted from a broadly tunable quantum cascade laser with a wavelength resolution smaller than 20 nm, is coupled through the diamond waveguides for attenuated total reflection spectroscopy. The expected advantages of these waveguides are a high sensitivity due to the high number of internal reflections along the propagation direction, a high transmittance in the mid-IR domain, the bio-compatibility of diamond and the possibility of functionalizing the surface layer. The sensor will be used for analyzing different forms of proteins such as α-synuclein which is relevant in understanding the mechanism behind Parkinson's disease. The fabrication process of the waveguide, its characteristics and several geometries are introduced. The optical setup of the biosensor is described and our first measurements on two analytes to demonstrate the principle of the sensing method will be presented. Future use of this sensor includes the functionalization of the diamond waveguide sensor surface to be able to fish out alpha-synuclein from cerebrospinal fluid.

  10. Multilayer Slab Waveguide Distributed Feedback Dye Laser Sensors

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Smith, Cameron; Leung, M.

    2013-01-01

    of DFB lasers. Here, we present a simple yet precise model for calculating the emission wavelength of multilayer DFB lasers. We ¯nd that experimental and calculated wavelength values are in compelling agreement for hybrid nanoimprinted Ormocomp-TiO2 (doped with Pyrromethene 597) ¯rst order DFB lasers [2...

  11. Ge22As20Se58 glass ultrafast laser inscribed waveguides for mid-IR integrated optics

    DEFF Research Database (Denmark)

    Morris, James M.; Mackenzie, Mark D.; Petersen, Christian Rosenberg

    2018-01-01

    Ultrafast laser inscription has been used to produce channel waveguides in Ge22As20Se58 glass (GASIR-1, Umicore N.V). The mode field diameter and waveguide losses at 2.94 mu m were measured along with the waveguide dispersion in the 1 to 4.5 mu m range, which is used to estimate the zero-dispersi...... ultrafast laser inscribed waveguide devices in GASIR-1 for mid-IR integrated optics applications. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.......Ultrafast laser inscription has been used to produce channel waveguides in Ge22As20Se58 glass (GASIR-1, Umicore N.V). The mode field diameter and waveguide losses at 2.94 mu m were measured along with the waveguide dispersion in the 1 to 4.5 mu m range, which is used to estimate the zero......-dispersion wavelength. Z-scan measurements of bulk samples have also been performed to determine the nonlinear refractive index. Finally, midIR supercontinuum generation has been shown when pumping the waveguides with femtosecond pulses centered at 4.6 mu m. Supercontinuum spanning approximately 4 mu m from 2.5 to 6...

  12. Investigation of single lateral mode for 852nm diode lasers with ridge waveguide design

    Science.gov (United States)

    Liu, Chu; Guan, Baolu; Mi, Guoxin; Liao, Yiru; Liu, Zhenyang; Li, Jianjun; Xu, Chen

    2016-11-01

    852nm Narrow linewidth lasers can be widely used in the field of ultra-fine spectrum measurement, Cs atomic clock control, satellite and optical fiber communication and so on. Furthermore, the stability of the single lateral mode is a very important condition to guarantee the narrow linewidth lasers. Here we investigate experimentally the influence of the narrow ridge structure and asymmetrical waveguide design on the stability single lateral mode of an 852nm diode laser. According to the waveguide theoretical analysis, ridge mesa etch depth (Δη , related to the refractive index difference of parallel to the junction) and ridge mesa width (the narrower the more control force to low order mode) are the main elements for lateral modes. In this paper, we designed different structures to investigate and verify major factors for lateral mode by experiment, and to confirm our thought. Finally, the 5μm mesa ridge laser, 800nm etch depth, with groove structure obtains excellent steady single lateral mode output by 150mA operating current and 30°C temperature. The optical spectrum FWHM is 0.5nm and side mode suppression ratio is 27dBm with uncoated. The laser with 1mm cavity length showed the threshold current of 50mA, a lasing wavelength of λ = 852.6nm, slope efficiency of above 0.7mW/mA. We accomplished single lateral mode of ridge waveguide edge-emitting lasers which can also be used as a laser source in the ultra-narrow linewidth external cavity laser system.

  13. Selection of modes in transverse-mode waveguides for semiconductor lasers based on asymmetric heterostructures

    International Nuclear Information System (INIS)

    Slipchenko, S. O.; Bondarev, A. D.; Vinokurov, D. A.; Nikolaev, D. N.; Fetisova, N. V.; Sokolova, Z. N.; Pikhtin, N. A.; Tarasov, I. S.

    2009-01-01

    Asymmetric Al 0.3 Ga 0.7 As/GaAs/InGaAs heterostructures with a broadened waveguide produced by the method of MOCVD epitaxy are studied. It is established that the precision shift of the active region to one of the cladding layers ensures the generation of the chosen mode of high order in the transverse broadened waveguide. It is experimentally established that this shift brings about an increase in internal optical losses and a decrease in the internal quantum efficiency of stimulated emission. It is shown experimentally that the shift of the active region to the n-type cladding layer governs the sublinear form of the power-current characteristic for semiconductor lasers; in the case of a shift of the active region towards the p-type cladding layer, the laser diodes demonstrated a linear dependence of optical power on the pump current in the entire range of pump currents.

  14. Cascaded-focus laser writing of low-loss waveguides in polymers.

    Science.gov (United States)

    Pätzold, Welm M; Reinhardt, Carsten; Demircan, Ayhan; Morgner, Uwe

    2016-03-15

    Waveguide writing in poly (methyl methacrylate) (PMMA) with femtosecond laser radiation is presented. An adequate refractive index change is induced in the border area below the irradiated focal volume. It supports an almost symmetric fundamental mode with propagation losses down to 0.5  dB/cm, the lowest losses observed so far in this class of materials. The writing process with a cascaded focus is demonstrated to be highly reliable over a large parameter range.

  15. 970-nm ridge waveguide diode laser bars for high power DWBC systems

    Science.gov (United States)

    Wilkens, Martin; Erbert, Götz; Wenzel, Hans; Knigge, Andrea; Crump, Paul; Maaßdorf, Andre; Fricke, Jörg; Ressel, Peter; Strohmaier, Stephan; Schmidt, Berthold; Tränkle, Günther

    2018-02-01

    de lasers are key components in material processing laser systems. While mostly used as pump sources for solid state or fiber lasers, direct diode laser systems using dense wavelength multiplexing have come on the market in recent years. These systems are realized with broad area lasers typically, resulting in beam quality inferior to disk or fiber lasers. We will present recent results of highly efficient ridge waveguide (RW) lasers, developed for dense-wavelength-beamcombining (DWBC) laser systems expecting beam qualities comparable to solid state laser systems and higher power conversion efficiencies (PCE). The newly developed RW lasers are based on vertical structures with an extreme double asymmetric large optical cavity. Besides a low vertical divergence these structures are suitable for RW-lasers with (10 μm) broad ridges, emitting in a single mode with a good beam quality. The large stripe width enables a lateral divergence below 10° (95 % power content) and a high PCE by a comparably low series resistance. We present results of single emitters and small test arrays under different external feedback conditions. Single emitters can be tuned from 950 nm to 975 nm and reach 1 W optical power with more than 55 % PCE and a beam quality of M2 < 2 over the full wavelength range. The spectral width is below 30 pm FWHM. 5 emitter arrays were stabilized using the same setup. Up to now we reached 3 W optical power, limited by power supply, with 5 narrow spectral lines.

  16. Propagation of highly aberrated laser beams in nonquadratic plasma waveguides

    International Nuclear Information System (INIS)

    Feit, M.D.; Fleck, J.A. Jr.; Morris, J.R.

    1977-01-01

    The propagation of a laser beam in a plasma column several meters long with a realistic electron density distribution is examined. The electron density distribution is based on laser-beam heating at z=0, but is otherwise uncoupled to the laser beam. The aberrated nature of the resulting lenslike medium leads to essentially aperiodic beam properties, which contrast with the completely periodic properties of Gaussian beams propagating in quadratic lenslike media. The beam is nonetheless stably trapped. These aberrated-beam properties also help to stabilize the beam against axial variations in refractive index

  17. Modeling of mode-locked coupled-resonator optical waveguide lasers

    DEFF Research Database (Denmark)

    Agger, Christian; Skovgård, Troels Suhr; Gregersen, Niels

    2010-01-01

    Coupled-resonator optical waveguides made from coupled high-Q photonic crystal nanocavities are investigated for use as cavities in mode-locked lasers. Such devices show great potential in slowing down light and can serve to reduce the cavity length of a mode-locked laser. An explicit expression...... of the emerging pulse train. A range of tuning around this frequency allows for effective mode locking. Finally, noise is added to the generalized single-cavity eigenfrequencies in order to evaluate the effects of fabrication imperfections on the cold-cavity transmission properties and consequently on the locking...

  18. Waveguide formation by laser backwriting ablation of metals unto glass substrates

    International Nuclear Information System (INIS)

    Rangel-Rojo, R.; Castelo, A.; Flores-Arias, M. T.; Gomez-Reino, C.; Lopez-Gascon, C.; Fuente, G. F. de la

    2008-01-01

    In this work we present experimental results for the generation of channel waveguides by a laser backwriting technique using a nanosecond pulsed Nd:YAG laser working at 1064 nm. We present a characterization of the resulting refractive index profile, using the refracted near-field technique, together with a spatially resolved chemical analysis based on energy dispersive x-ray analysis(EDX). The EDX results confirm that metal ions are embedded in a region close to the substrate interface, up to about a 5 μm depth. We also present a discussion of the physical mechanisms that produce the profiles measured

  19. Waveguide formation by laser backwriting ablation of metals unto glass substrates

    Energy Technology Data Exchange (ETDEWEB)

    Rangel-Rojo, R [Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2732, Ensenada BC 22860 (Mexico); Castelo, A; Flores-Arias, M T; Gomez-Reino, C [GRIN Optics Group. Applied Physics Department, Escola Universitaria de Optica e Optometria, Universidad de Santiago de Compostela, Campus Sur s/n, E15782 Santiago de Compostela, Espana (Spain); Lopez-Gascon, C; Fuente, G F. de la [Instituto de Ciencia de Materiales de Aragon (U. Zaragoza-CSIC), Ma. de Luna 3, E50018 Zaragoza (Spain)

    2008-04-15

    In this work we present experimental results for the generation of channel waveguides by a laser backwriting technique using a nanosecond pulsed Nd:YAG laser working at 1064 nm. We present a characterization of the resulting refractive index profile, using the refracted near-field technique, together with a spatially resolved chemical analysis based on energy dispersive x-ray analysis(EDX). The EDX results confirm that metal ions are embedded in a region close to the substrate interface, up to about a 5 {mu}m depth. We also present a discussion of the physical mechanisms that produce the profiles measured.

  20. Broadband Optical Active Waveguides Written by Femtosecond Laser Pulses in Lithium Fluoride

    International Nuclear Information System (INIS)

    Chiamenti, Ismael; Costa, Larissa N. da; Kalinowski, Hypolito J.; Bonfigli, Francesca; Montereali, Rosa Maria; Gomes Anderson, S. L.

    2014-01-01

    Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 nm, to near-infrared, at 1550 nm. Visible photoluminescence spectra of the optically active F 2 and F 3 + color centers produced by the fs laser writing process were measured. The wavelength-dependent refractive index increase was estimated to be in the order of 10 −3 −10 −4 in the visible and near-infrared spectral intervals, which is consistent with the stable formation of point defects in LiF

  1. Broadband Optical Active Waveguides Written by Femtosecond Laser Pulses in Lithium Fluoride

    Science.gov (United States)

    Ismael, Chiamenti; Francesca, Bonfigli; Anderson, S. L. Gomes; Rosa, Maria Montereali; Larissa, N. da Costa; Hypolito, J. Kalinowski

    2014-01-01

    Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 nm, to near-infrared, at 1550 nm. Visible photoluminescence spectra of the optically active F2 and F3+ color centers produced by the fs laser writing process were measured. The wavelength-dependent refractive index increase was estimated to be in the order of 10-3-10-4 in the visible and near-infrared spectral intervals, which is consistent with the stable formation of point defects in LiF.

  2. A Helical Undulator Wave-guide Inverse Free-Electron Laser

    International Nuclear Information System (INIS)

    Rosenzweig, J.; Bodzin, N.; Frigola, P.; Musumeci, P.; Pellegrini, C.; Travish, G.; Joshi, C.; Tochitsky, S.

    2004-01-01

    With recent success in high gradient, high-energy gain IFEL experiments at the UCLA Neptune Laboratory, future experiments are now being contemplated. The Neptune IFEL was designed to use a tightly focused, highly diffracting, near-TW peak power 10 micron laser. This choice of laser focusing, driven by power-handling limitations of the optics near the interaction region, led to design and use of a very complex undulator, and to sensitivity to both laser misalignment and focusing errors. As these effects limited the performance of the IFEL experiment, a next generation experiment at Neptune has been studied which avoids the use of a highly diffractive laser beam through use of a waveguide. We discuss here the choice of low-loss waveguide, guided mode characteristics and likely power limitations. We also examine a preferred undulator design, which is chosen to be helical in order to maximize the acceleration achieved for a given power. With the limitations of these laser and undulator choices in mind, we show the expected performance of the IFEL using 1D simulations. Three-dimensional effects are examined, in the context of use of a solenoid for focusing and acceleration enhancement

  3. Fiber-Type Random Laser Based on a Cylindrical Waveguide with a Disordered Cladding Layer.

    Science.gov (United States)

    Zhang, Wei Li; Zheng, Meng Ya; Ma, Rui; Gong, Chao Yang; Yang, Zhao Ji; Peng, Gang Ding; Rao, Yun Jiang

    2016-05-25

    This letter reports a fiber-type random laser (RL) which is made from a capillary coated with a disordered layer at its internal surface and filled with a gain (laser dye) solution in the core region. This fiber-type optical structure, with the disordered layer providing randomly scattered light into the gain region and the cylindrical waveguide providing confinement of light, assists the formation of random lasing modes and enables a flexible and efficient way of making random lasers. We found that the RL is sensitive to laser dye concentration in the core region and there exists a fine exponential relationship between the lasing intensity and particle concentration in the gain solution. The proposed structure could be a fine platform of realizing random lasing and random lasing based sensing.

  4. Control of waveguide properties by tuning femtosecond laser induced compositional changes

    International Nuclear Information System (INIS)

    Hoyo, Jesús; Fernandez, Toney Teddy del; Siegel, Jan; Solis, Javier; Vazquez, Rebeca Martinez; Osellame, Roberto; Sotillo, Belén; Fernández, Paloma

    2014-01-01

    Local compositional changes induced by high repetition rate fs-laser irradiation can be used to produce high performance optical waveguides in phosphate-based glasses. The waveguide refractive index contrast is determined by the local concentration of La, which can be changed by the action of the writing laser pulses. In this work, we have investigated the degree of control that can be exerted using this waveguide writing mechanism over the cross-section of the guiding region, and the local refractive index and compositional changes induced. These variables can be smoothly controlled via processing parameters using the slit shaping technique with moderate Numerical Aperture (NA 0.68) writing optics. The combined use of X-ray microanalysis and near field refractive index profilometry evidences a neat linear correlation between local La content and refractive index increase over a broad Δn interval (>3 × 10 −2 ). This result further confirms the feasibility of generating efficient, integrated optics elements via spatially selective modification of the glass composition.

  5. Control of waveguide properties by tuning femtosecond laser induced compositional changes

    Energy Technology Data Exchange (ETDEWEB)

    Hoyo, Jesús; Fernandez, Toney Teddy del; Siegel, Jan; Solis, Javier, E-mail: j.solis@io.cfmac.csic.es [Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, 28006 Madrid (Spain); Vazquez, Rebeca Martinez; Osellame, Roberto [Instituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Sotillo, Belén; Fernández, Paloma [Depto. de Física de Materiales, Facultad de Físicas, Univ. Complutense, 28040 Madrid (Spain)

    2014-09-29

    Local compositional changes induced by high repetition rate fs-laser irradiation can be used to produce high performance optical waveguides in phosphate-based glasses. The waveguide refractive index contrast is determined by the local concentration of La, which can be changed by the action of the writing laser pulses. In this work, we have investigated the degree of control that can be exerted using this waveguide writing mechanism over the cross-section of the guiding region, and the local refractive index and compositional changes induced. These variables can be smoothly controlled via processing parameters using the slit shaping technique with moderate Numerical Aperture (NA 0.68) writing optics. The combined use of X-ray microanalysis and near field refractive index profilometry evidences a neat linear correlation between local La content and refractive index increase over a broad Δn interval (>3 × 10{sup −2}). This result further confirms the feasibility of generating efficient, integrated optics elements via spatially selective modification of the glass composition.

  6. Multi-wavelength laser based on an arrayed waveguide grating and Sagnac loop reflectors monolithically integrated on InP

    NARCIS (Netherlands)

    Muñoz, P.; García-Olcina, R.; Doménech, J.D.; Rius, M.; Capmany, J.; Chen, L.R.; Habib, C.; Leijtens, X.J.M.; Vries, de T.; Heck, M.J.R.; Augustin, L.M.; Nötzel, R.; Robbins, D.J.

    2010-01-01

    In this paper, a multi-wavelength laser monolithically integrated on InP is presented. A linear laser cavity is built between two integrated Sagnac loop reflectors, with an Arrayed Waveguide Grating (AWG) as frequency selective device, and Semiconductor Optical Amplifiers (SOA) as gain sections. The

  7. Direct femtosecond laser writing of buried infrared waveguides in chalcogenide glasses

    Science.gov (United States)

    Le Coq, D.; Bychkov, E.; Masselin, P.

    2016-02-01

    Direct laser writing technique is now widely used in particular in glass, to produce both passive and active photonic devices. This technique offers a real scientific opportunity to generate three-dimensional optical components and since chalcogenide glasses possess transparency properties from the visible up to mid-infrared range, they are of great interest. Moreover, they also have high optical non-linearity and high photo-sensitivity that make easy the inscription of refractive index modification. The understanding of the fundamental and physical processes induced by the laser pulses is the key to well-control the laser writing and consequently to realize integrated photonic devices. In this paper, we will focus on two different ways allowing infrared buried waveguide to be obtained. The first part will be devoted to a very original writing process based on a helical translation of the sample through the laser beam. In the second part, we will report on another original method based on both a filamentation phenomenon and a point by point technique. Finally, we will demonstrate that these two writing techniques are suitable for the design of single mode waveguide for wavelength ranging from the visible up to the infrared but also to fabricate optical components.

  8. Single scan femtosecond laser transverse writing of depressed cladding waveguides enabled by three-dimensional focal field engineering.

    Science.gov (United States)

    Zhang, Qian; Yang, Dong; Qi, Jia; Cheng, Ya; Gong, Qihuang; Li, Yan

    2017-06-12

    We report single scan transverse writing of depressed cladding waveguides inside ZBLAN glass with the longitudinally oriented annular ring-shaped focal intensity distribution of the femtosecond laser. The entire region of depressed cladding at the cross section, where a negative change of refraction index is induced, can be modified simultaneously with the ring-shaped focal intensity profile. The fabricated waveguides exhibit good single guided mode.

  9. Waveguide embedded plasmon laser with multiplexing and electrical modulation

    Science.gov (United States)

    Ma, Ren-min; Zhang, Xiang

    2017-08-29

    This disclosure provides systems, methods, and apparatus related to nanometer scale lasers. In one aspect, a device includes a substrate, a line of metal disposed on the substrate, an insulating material disposed on the line of metal, and a line of semiconductor material disposed on the substrate and the insulating material. The line of semiconductor material overlaying the line of metal, disposed on the insulating material, forms a plasmonic cavity.

  10. Passively Q-switched of EDFL employing multi-walled carbon nanotubes with diameter less than 8 nm as saturable absorber

    Directory of Open Access Journals (Sweden)

    Zuikafly Siti Nur Fatin

    2017-01-01

    Full Text Available The paper demonstrates passively Q-switched erbium-doped fiber laser implementing multiwalled carbon nanotubes (MWCNTs based saturable absorber. The paper is the first to report the use of the MWCNTs with diameter less than 8 nm as typically, the diameter used is 10 to 20 nm. The MWCNTs is incorporated with water soluble host polymer, polyvinyl alcohol (PVA to produce a MWCNTs polymer composite thin film which is then sandwiched between two fiber connectors. The fabricated SA is employed in the laser experimental setup in ring cavity. The Q-switching regime started at threshold pump power of 103 mW and increasable to 215 mW. The stable pulse train from 41.6 kHz to 76.92 kHz with maximum average output power and pulse energy of 0.17 mW and 3.39 nJ are produced. The shortest pulse width of 1.9 μs is obtained in the proposed experimental work, making it the lowest pulse width ever reported using MWCNTs-based saturable absorber.

  11. Metal-clad waveguide characterization for contact-based light transmission into tissue

    Science.gov (United States)

    Chininis, Jeffrey; Whiteside, Paul; Hunt, Heather K.

    2016-02-01

    As contemporary laser dermatology procedures, like tattoo removal and skin resurfacing, become more popular, the complications of their operation are also becoming more prevalent. Frequent incidences of over-exposure, ocular injury, and excessive thermal damage represent mounting concerns for those seeking such procedures; moreover, each of these problems is a direct consequence of the standard, free-space method of laser transmission predominantly used in clinical settings. Therefore, an alternative method of light transmission is needed to minimize these problems. Here, we demonstrate and characterize an alternative method that uses planar waveguides to deliver light into sample tissue via direct contact. To do this, slab substrates made from glass were clad in layers of titanium and silver, constraining the light within the waveguide along the waveguide's length. By creating active areas on the waveguide surface, the propagating light could then optically tunnel into the tissue sample, when the waveguide was brought into contact with the tissue. SEM and EDS were used to characterize the metal film thickness and deposition rates onto the glass substrates. Laser light from a Q-switched Nd:YAG source operating at 532nm was coupled into the waveguide and transmitted into samples of pig skin. The amount of light transmitted was measured using photoacoustics techniques, in conjunction with a photodiode and integrating sphere. Transmitting light into tissue in this manner effectively resolves or circumvents the complications caused by free-space propagation methods as it reduces the operating distance to 0, which prevents hazardous back-reflections and allows for the ready incorporation of contact cooling technologies.

  12. Bright X-ray source from a laser-driven micro-plasma-waveguide

    CERN Document Server

    Yi, Longqing

    2016-01-01

    Bright tunable x-ray sources have a number of applications in basic science, medicine and industry. The most powerful sources are synchrotrons, where relativistic electrons are circling in giant storage rings. In parallel, compact laser-plasma x-ray sources are being developed. Owing to the rapid progress in laser technology, very high-contrast femtosecond laser pulses of relativistic intensities become available. These pulses allow for interaction with micro-structured solid-density plasma without destroying the structure by parasitic pre-pulses. The high-contrast laser pulses as well as the manufacturing of materials at micro- and nano-scales open a new realm of possibilities for laser interaction with photonic materials at the relativistic intensities. Here we demonstrate, via numerical simulations, that when coupling with a readily available 1.8 Joule laser, a micro-plasma-waveguide (MPW) may serve as a novel compact x-ray source. Electrons are extracted from the walls by the laser field and form a dense ...

  13. Improving the beam quality of high-power laser diodes by introducing lateral periodicity into waveguides

    Science.gov (United States)

    Sobczak, Grzegorz; DÄ browska, ElŻbieta; Teodorczyk, Marian; Kalbarczyk, Joanna; MalÄ g, Andrzej

    2013-01-01

    Low quality of the optical beam emitted by high-power laser diodes is the main disadvantage of these devices. The two most important reasons are highly non-Gaussian beam profile with relatively wide divergence in the junction plane and the filamentation effect. Designing laser diode as an array of narrow, close to each other single-mode waveguides is one of the solutions to this problem. In such devices called phase locked arrays (PLA) there is no room for filaments formation. The consequence of optical coupling of many single-mode waveguides is the device emission in the form of few almost diffraction limited beams. Because of losses in regions between active stripes the PLA devices have, however, somewhat higher threshold current and lower slope efficiencies compared to wide-stripe devices of similar geometry. In this work the concept of the high-power laser diode resonator consisted of joined PLA and wide stripe segments is proposed. Resulting changes of electro-optical characteristics of PLA are discussed. The devices are based on the asymmetric heterostructure designed for improvement of the catastrophic optical damage threshold as well as thermal and electrical resistances. Due to reduced distance from the active layer to surface in this heterostructure, better stability of current (and gain) distribution with changing drive level is expected. This could lead to better stability of optical field distribution and supermodes control. The beam divergence reduction in the direction perpendicular of the junction plane has been also achieved.

  14. Laser-induced nonlinear crystalline waveguide on glass fiber format and diode-pumped second harmonic generation

    Science.gov (United States)

    Shi, Jindan; Feng, Xian

    2018-03-01

    We report a diode pumped self-frequency-doubled nonlinear crystalline waveguide on glass fiber. A ribbon fiber has been drawn on the glass composition of 50GeO2-25B2O3-25(La,Yb)2O3. Surface channel waveguides have been written on the surface of the ribbon fiber, using space-selective laser heating method with the assistance of a 244 nm CW UV laser. The Raman spectrum of the written area indicates that the waveguide is composed of structure-deformed nonlinear (La,Yb)BGeO5 crystal. The laser-induced surface wavy cracks have also been observed and the forming mechanism of the wavy cracks has been discussed. Efficient second harmonic generation has been observed from the laser-induced crystalline waveguide, using a 976 nm diode pump. 13 μW of 488 nm output has been observed from a 17 mm long waveguide with 26.0 mW of launched diode pump power, corresponding to a normalized conversion efficiency of 4.4%W-1.

  15. Tapered waveguide InGaAs/InGaAsP multiple-quantum-well lasers

    International Nuclear Information System (INIS)

    Koch, T.L.; Koren, U.; Eisentein, G.; Young, M.G.; Oron, M.; Giles, C.R.; Miller, B.I.

    1990-01-01

    The authors propose and demonstrate the application of ultra-thin etch-stop fabrication techniques to adiabatically expand the vertical optical mode size in 1.5 μm InGaAs/InGaAsP MQW lasers using a tapered-core passive intracavity waveguide structure. They achieve 30% differential quantum efficiency out the tapered facet, far-field FWHM of ∼ 12 degrees, and a butt-coupling efficiency into a cleaved fiber of - 4.2 dB, with - 1 dB alignment tolerances of ∼ ± 3 μM

  16. Modelling of a DBR laser based on Raman effect in a silicon-on-insulator rib waveguide

    International Nuclear Information System (INIS)

    De Leonardis, Francesco; Dimastrodonato, Valeria; Passaro, Vittorio M N

    2008-01-01

    In this paper, third-order nonlinearities in silicon-on-insulator rib waveguides are investigated to obtain complete modelling, describing the behaviour of a stimulated Raman scattering based laser. The simulations of a distributed Bragg reflector laser operation in a time domain allow for the first time to study in detail the dependence of threshold and output powers on different device parameters. Both continuous wave and pulsed laser operations are theoretically demonstrated, as well as their dependence on device parameters

  17. Femtosecond laser direct writing of gratings and waveguides in high quantum efficiency erbium-doped Baccarat glass

    International Nuclear Information System (INIS)

    Vishnubhatla, K C; Kumar, R Sai Santosh; Rao, D Narayana; Rao, S Venugopal; Osellame, R; Ramponi, R; Bhaktha, S N B; Mattarelli, M; Montagna, M; Turrell, S; Chiappini, A; Chiasera, A; Ferrari, M; Righini, G C

    2009-01-01

    The femtosecond laser direct writing technique was employed to inscribe gratings and waveguides in high quantum efficiency erbium-doped Baccarat glass. Using the butt coupling technique, a systematic study of waveguide loss with respect to input pulse energy and writing speed was performed to achieve the best waveguide with low propagation loss (PL). By pumping at 980 nm, we observed signal enhancement in these active waveguides in the telecom spectral region. The refractive index change was smooth and we estimated it to be ∼10 -3 . The high quantum efficiency (∼80%) and a best PL of ∼0.9 dB cm -1 combined with signal enhancement makes Baccarat glass a potential candidate for application in photonics.

  18. High slope efficiency and high refractive index change in direct-written Yb-doped waveguide lasers with depressed claddings.

    Science.gov (United States)

    Palmer, Guido; Gross, Simon; Fuerbach, Alexander; Lancaster, David G; Withford, Michael J

    2013-07-15

    We report the first Yb:ZBLAN and Yb:IOG10 waveguide lasers fabricated by the fs-laser direct-writing technique. Pulses from a Titanium-Sapphire laser oscillator with 5.1 MHz repetition rate were utilized to generate negative refractive index modifications in both glasses. Multiple modifications were aligned in a depressed cladding geometry to create a waveguide. For Yb:ZBLAN we demonstrate high laser slope efficiency of 84% with a maximum output power of 170 mW. By using Yb:IOG10 a laser performance of 25% slope efficiency and 72 mW output power was achieved and we measured a remarkably high refractive index change exceeding Δn = 2.3 × 10(-2).

  19. Suppression of parasitic oscillations in a core-doped ceramic Nd:YAG laser by Sm:YAG cladding.

    Science.gov (United States)

    Huss, Rafael; Wilhelm, Ralf; Kolleck, Christian; Neumann, Jörg; Kracht, Dietmar

    2010-06-07

    The onset of parasitic oscillations limits the extraction efficiency and therefore energy scaling of Q-switched lasers. A solid-state laser was end pumped with a fiber-coupled diode laser and operated in q-cw as well as in passively Q-switched operation. For Q-switched operation, we demonstrate the suppression of parasitic oscillations in a core-doped ceramic Nd:YAG laser by Sm:YAG cladding.

  20. 1.5  kW efficient CW Nd:YAG planar waveguide MOPA laser.

    Science.gov (United States)

    Wang, Juntao; Wu, Zhenhai; Su, Hua; Zhou, Tangjian; Lei, Jun; Lv, Wenqiang; He, Jing; Xu, Liu; Chen, Yuejian; Wang, Dan; Tong, Lixin; Hu, Hao; Gao, Qingsong; Tang, Chun

    2017-08-15

    In this Letter, we report a 1064 nm continuous wave Nd:YAG planar waveguide laser with an output power of 1544 W based on the structure of the master oscillator power amplification. A fiber laser is used as the master oscillator, and diode laser arrays are used as the pump source of the waveguide laser amplifier. The dimension of the waveguide is 1  mm (T)×10  mm (W)×60  mm (L), and the dual end oblique pumping is adopted with different angles. After a single-pass amplification, the power is scaled from 323 to 1544 W with the pump power of 2480 W, leading to an optical-to-optical efficiency of 49%. At the maximum output, the beam quality M 2 are measured to be 2.8 and 7.0 in the guided direction and the unguided direction, respectively. To the best of our knowledge, this is the highest output power of a Nd:YAG planar waveguide laser to date.

  1. Laser performance and modeling of RE3+:YAG double-clad crystalline fiber waveguides

    Science.gov (United States)

    Li, Da; Lee, Huai-Chuan; Meissner, Stephanie K.; Meissner, Helmuth E.

    2018-02-01

    We report on laser performance of ceramic Yb:YAG and single crystal Tm:YAG double-clad crystalline fiber waveguide (CFW) lasers towards the goal of demonstrating the design and manufacturing strategy of scaling to high output power. The laser component is a double-clad CFW, with RE3+:YAG (RE = Yb, Tm respectively) core, un-doped YAG inner cladding, and ceramic spinel or sapphire outer cladding. Laser performance of the CFW has been demonstrated with 53.6% slope efficiency and 27.5-W stable output power at 1030-nm for Yb:YAG CFW, and 31.6% slope efficiency and 46.7-W stable output power at 2019-nm for Tm:YAG CFW, respectively. Adhesive-Free Bond (AFB®) technology enables a designable refractive index difference between core and inner cladding, and designable core and inner cladding sizes, which are essential for single transverse mode CFW propagation. To guide further development of CFW designs, we present thermal modeling, power scaling and design of single transverse mode operation of double-clad CFWs and redefine the single-mode operation criterion for the double-clad structure design. The power scaling modeling of double-clad CFW shows that in order to achieve the maximum possible output power limited by the physical properties, including diode brightness, thermal lens effect, and simulated Brillion scattering, the length of waveguide is in the range of 0.5 2 meters. The length of an individual CFW is limited by single crystal growth and doping uniformity to about 100 to 200 mm lengths, and also by availability of starting crystals and manufacturing complexity. To overcome the limitation of CFW lengths, end-to-end proximity-coupling of CFWs is introduced.

  2. TE modes of UV-laser generated waveguides in a planar polymer chip of parabolic refractive index profile

    Science.gov (United States)

    Shams El-Din, M. A.

    2018-04-01

    The UV-laser lithographic method is used for the preparation of Polymeric integrated-optical waveguides in a planar polymer chip. The waveguide samples are irradiated by an excimer laser of wavelength 248 nm with different doses and with the same fluencies. The refractive index depth profile for the waveguides, in the first zone is found to have a parabolic shape and Gaussian shape in the second one that can be determined by Mach-Zehnder interferometer. Both the mode field distribution and the effective mode indices for the first zone only are determined by making use of the theoretical mode and the experimental data. It is found that the model field distribution is strongly dependent on the refractive indices for each zone.

  3. Ultra-photo-stable coherent random laser based on liquid waveguide gain channels doped with boehmite nanosheets

    Science.gov (United States)

    Zhang, Hua; Zhang, Hong; Yang, Chao; Dai, Jiangyun; Yin, Jiajia; Xue, Hongyan; Feng, Guoying; Zhou, Shouhuan

    2018-02-01

    Construction of ultra-photo-stable coherent random laser based on liquid waveguide gain channels doped with boehmite nanosheets has been demonstrated. An Al plate uniformly coated with boehmite nanosheets was prepared by an alkali-treatment method and used as a scattering surface for the coherent random laser. Microcavity may be formed between these boehmite nanosheets owing to the strong optical feedback induced by the multiple light scattering. Many sharp peaks are observed in the emission spectra, and their laser thresholds are different, which confirms the feedback mechanism is coherent. The linewidth of the main peak at 571.74 nm is 0.28 nm, and the threshold of the main peak is about 4.96 mJ/cm2. Due to the fluidity of liquid waveguide gain medium, the photostability of this coherent random laser is better than the conventional solid state dye random lasers. The emission direction is well constrained by the waveguide effect within a certain angular range (±30°). This kind of coherent random laser can be applied in optical fluid lasers and photonic devices.

  4. Femtosecond laser writing of new type of waveguides in silver containing glasses (Conference Presentation)

    Science.gov (United States)

    Abou Khalil, Alain; Bérubé, Jean-Philippe; Danto, Sylvain; Desmoulin, Jean-Charles; Cardinal, Thierry; Petit, Yannick G.; Canioni, Lionel; Vallée, Réal

    2017-03-01

    Femtosecond laser writing in glasses is a growing field of research and development in photonics, since it provides a versatile, robust and efficient approach to directly address 3D material structuring. Laser-glass interaction process has been studied for many years, especially the local changes of the refractive index that have been classified by three distinct types (types I, II and III, respectively). These refractive index modifications are widely used for the creation of photonics devices such as waveguides [1], couplers, photonic crystals to fabricate integrated optical functions in glasses for photonic applications as optical circuits or integrated sensors. Femtosecond laser writing in a home-developed silver containing zinc phosphate glasses induces the creation of fluorescent silver clusters distributed around the laser-glass interaction voxel [2]. In this paper, we introduce a new type of refractive index modification in glasses. It is based on the creation of these photo-induced silver clusters allowing a local change in the refractive index Δn = 5×10-3, which is sufficient for the creation of waveguides and photonics devices. The wave guiding process in our glasses along these structures with original geometry is demonstrated for wavelengths from visible to NIR [3], giving a promising access to integrated optical circuits in these silver containing glasses. Moreover, the characterization of the waveguides is presented, including their original geometry, the refractive index change, the mode profile, the estimation of propagation losses and a comparison with simulation results. 1. K. M. Davis, K. Miura, N. Sugimoto, and K. Hirao, Opt. Lett. 21, 1729-1731 (1996). 2. M. Bellec, A. Royon, K. Bourhis, J. Choi, B. Bousquet, M. Treguer, T. Cardinal, J.-J. Videau, M. Richardson, and L. Canioni, The Journal of Physical Chemistry C 114, 15584-15588 (2010). 3. S. Danto, F. Désévédavy, Y. Petit, J.-C. Desmoulin, A. Abou Khalil, C. Strutynski, M. Dussauze, F

  5. Influence of the electric field frequency on the performance of a RF excited CO2 waveguide laser

    NARCIS (Netherlands)

    Ochkin, V.N.; Witteman, W.J.; Ilukhin, B.I.; Kochetov, I.V.; Peters, P.J.M.; Udalov, Yu.B.; Tskhai, S.N.

    1996-01-01

    An analysis is presented of the effect of the RF frequency on the active media of CO2 waveguide lasers. It is found that the characteristics are improved with increasing RF frequency because the space charge sheath width decreases with increasing excitation frequency. We also found that the sheath

  6. The formation and optical properties of planar waveguide in laser crystal Nd:YGG by carbon ion implantation

    Science.gov (United States)

    Zhao, Jin-Hua; Qin, Xi-Feng; Wang, Feng-Xiang; Jiao, Yang; Guan, Jing; Fu, Gang

    2017-10-01

    As one kind of prominent laser crystal, Nd:Y3Ga5O12 (Nd:YGG) crystal has outstanding performance on laser excitation at multi-wavelength which have shown promising applications in optical communication field. In addition, Nd:YGG crystal has potential applications in medical field due to its ability of emit the laser at 1110 nm. Optical waveguide structure with high quality could improve the efficiency of laser emission. In this work, we fabricated the optical planar waveguide on Nd:YGG crystal by medium mass ion implantation which was convinced an effective method to realize a waveguide structure with superior optical properties. The sample is implanted by C ions at energy of 5.0 MeV with the fluence of 1 × 1015 ions/cm2. We researched the optical propagation properties in the Nd:YGG waveguide by end-face coupling and prism coupling method. The Nd ions fluorescent properties are obtained by a confocal micro-luminescence measurement. The fluorescent properties of Nd ions obtained good reservation after C ion implantation. Our work has reference value for the application of Nd:YGG crystal in the field of optical communication.

  7. Competition of Faraday rotation and birefringence in femtosecond laser direct written waveguides in magneto-optical glass.

    Science.gov (United States)

    Liu, Qiang; Gross, S; Dekker, P; Withford, M J; Steel, M J

    2014-11-17

    We consider the process of Faraday rotation in femtosecond laser direct-write waveguides. The birefringence commonly associated with such waveguides may be expected to impact the observable Faraday rotation. Here, we theoretically calculate and experimentally verify the competition between Faraday rotation and birefringence in two waveguides created by laser writing in a commercial magneto-optic glass. The magnetic field applied to induce Faraday rotation is nonuniform, and as a result, we find that the two effects can be clearly separated and used to accurately determine even weak birefringence. The birefringence in the waveguides was determined to be on the scale of Δn = 10(-6) to 10(-5). The reduction in Faraday rotation caused by birefringence of order Δn = 10(-6) was moderate and we obtained approximately 9° rotation in an 11 mm waveguide. In contrast, for birefringence of order 10(-5), a significant reduction in the polarization azimuth change was found and only 6° rotation was observed.

  8. Ultrafast laser writing of optical waveguides in ceramic Yb:YAG: a study of thermal and non-thermal regimes

    Energy Technology Data Exchange (ETDEWEB)

    Benayas, A.; Jaque, D. [Universidad Autonoma de Madrid, Departamento de Fisica de Materiales, Madrid (Spain); Silva, W.F.; Jacinto, C. [Universidade Federal de Alagoas, Grupo de Fotonica e Fluidos Complexos, Instituto de Fisica, Maceio, Alagoas (Brazil); Rodenas, A.; Thomsom, R.R.; Psaila, N.D.; Reid, D.T.; Kar, A.K. [Heriot-Watt University, School of Engineering and Physical Sciences, Edinburgh (United Kingdom); Vazquez de Aldana, J. [Universidad de Salamanca, Grupo de Optica, Departamento de Fisica Aplicada, Facultad de Ciencias Fisicas, Salamanca (Spain); Chen, F.; Tan, Y. [Shandong University, School of Physics, Jinan (China); Torchia, G.A. [CONICET-CIC, Centro de Investigaciones Opticas, La Plata (Argentina)

    2011-07-15

    We report the improvement of ultrafast laser written optical waveguides in Yb:YAG ceramics by tailoring the presence of heat accumulation effects. From a combination of ytterbium micro-luminescence and micro-Raman structural analysis, maps of lattice defects and stress fields have been obtained. We show how laser annealing can strongly reduce the concentration of defects and also reduce compressive stress, leading to an effective 50% reduction in the propagation losses and to more extended and symmetric propagation modes. (orig.)

  9. Second Harmonic Generation of Violet Light in Femtosecond-Laser-Inscribed BiB3O6 Cladding Waveguides

    Directory of Open Access Journals (Sweden)

    Jia Yuechen

    2013-11-01

    Full Text Available We report on the second harmonic generation of violet light of a nonlinear cladding waveguide in BiB3O6 crystal produced by femtosecond laser inscription. Under continuous-wave pump laser at 800 nm, the guided second harmonic wave at 400 nm with a conversion efficiency of ~0.32% has been realized through the Type I birefringence phase matching configuration.

  10. Highly efficient single-pass frequency doubling of a continuous-wave distributed feedback laser diode using a PPLN waveguide crystal at 488 nm.

    Science.gov (United States)

    Jechow, Andreas; Schedel, Marco; Stry, Sandra; Sacher, Joachim; Menzel, Ralf

    2007-10-15

    A continuous-wave distributed feedback diode laser emitting at 976 nm was frequency doubled by the use of a periodically poled lithium niobate waveguide crystal with a channel size of 3 microm x 5 microm and an interaction length of 10 mm. A laser to waveguide coupling efficiency of 75% could be achieved resulting in 304 mW of incident infrared light inside the waveguide. Blue laser light emission of 159 mW at 488 nm has been generated, which equals to a conversion efficiency of 52%. The resulting wall plug efficiency was 7.4%.

  11. Polarization of eigenmodes in laser diode waveguides on semipolar and nonpolar GaN

    Energy Technology Data Exchange (ETDEWEB)

    Rass, Jens; Vogt, Patrick [Institute of Solid State Physics, Technische Universitaet Berlin (Germany); Wernicke, Tim; Einfeldt, Sven; Weyers, Markus [Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Berlin (Germany); Scheibenzuber, Wolfgang G.; Schwarz, Ulrich T. [Department of Physics, Regensburg University (Germany); Kupec, Jan [Integrated Systems Laboratory, ETH Zurich (Switzerland); Witzigmann, Bernd [Computational Electronics and Photonics Group, University of Kassel (Germany); Kneissl, Michael [Institute of Solid State Physics, Technische Universitaet Berlin (Germany); Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Berlin (Germany)

    2010-02-15

    Recent calculations of the eigenmodes in waveguides grown on semipolar GaN suggest that the optical polarization of the emitted light as well as the optical gain depends on the orientation of the resonator. Our measurements on separate confinement heterostructures on semipolar (11 anti 22) and (10 anti 12) GaN show that for laser resonators along the semipolar [11 anti 2 anti 3 ] and [0 anti 111] directions (i.e. the projection of the c-axis onto the plane of growth) the threshold for amplified spontaneous emission is lower than for the nonpolar direction and that the stimulated emission is linearly polarized as TE mode. For the waveguide structures along the nonpolar [1 anti 100] or [11 anti 20] direction on the other hand, birefringence and anisotropy of the optical gain in the plane of growth leads not only to a higher threshold but also to a rotation of the optical polarization which is not any more TE- or TM-polarized but influenced by the ordinary and extraordinary refractive index of the material. We observe stimulated emission into a mode which is linearly polarized in extraordinarydirection nearly parallel to the c-axis. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Near-field microscopy of waveguide architectures of InGaN/GaN diode lasers

    Science.gov (United States)

    Friede, Sebastian; Tomm, Jens W.; Kühn, Sergei; Hoffmann, Veit; Wenzel, Hans; Weyers, Markus

    2016-11-01

    Waveguide (WG) architectures of 420 nm emitting InGaN/GaN diode lasers are analyzed by photoluminescence and photocurrent spectroscopy using a nearfield scanning optical microscope that scans along their front facets. The components of the ‘optical active cavity’, quantum wells, WGs, and cladding layers are individually inspected with a spatial resolution of ∼100 nm. Separate analysis of the p- and n-sections of the WG was achieved, and reveals defect levels in the p-part. Moreover, it is demonstrated that the homogeneity of the n-WG section directly affects the quantum wells that are grown on top of this layer. Substantially increased carrier capture efficiencies into InGaN/GaN-WGs compared to GaN-WGs are demonstrated.

  13. Novel O-band tunable fiber laser using an array waveguide grating

    International Nuclear Information System (INIS)

    Ahmad, H; Zulkifli, M Z; Latif, A A; Harun, S W

    2010-01-01

    A novel tunable fibre laser (TFL) operating in the ordinary band (O-band) of 1310 nm is proposed and demonstrated. The proposed TFL is developed using a 1×16 arrayed waveguide grating (AWG) as a slicing mechanism for the broadband amplified spontaneous emission (ASE) source and an optical channel selector (OCS) to provide the tunability. A semiconductor optical amplifier (SOA) with a centre wavelength of 1310 nm serves as the compact gain medium for the TFL and also as a broadband ASE source. The TFL has a tuning range of 1301.26 nm to 1311.18 nm with 9.92 nm span and a channel spacing of 0.7 nm. The measured output power is about –4 and –8 dBm and with a side node suppression ratio (SMSR) of 29 to 33 dB

  14. Device geometry considerations for ridge waveguide quantum dot mode-locked lasers

    International Nuclear Information System (INIS)

    Mee, J K; Raghunathan, R; Lester, L F; Wright, J B

    2014-01-01

    Quantum dot mode-locked lasers have emerged as a leading source for the efficient generation of high-quality optical pulses from a compact package, attracting considerable attention for support of multiple high-speed applications, owing to characteristics such as low noise operation and high pulse peak power, in addition to the ability to multiplex the output pulse train in temporal and frequency domains in order to obtain hundreds of GHz pulse repetition rates potentially operating at 1 Tbps. This topical review provides a detailed explanation into the primary advantages of quantum dots, identifying the key features that have made them superior to other material systems for passive mode-locking in semiconductor lasers. Following this account, the impact of the device's cavity geometry on the operational range of two-section, monolithic passively mode-locked lasers is investigated both experimentally and analytically. A model is described that predicts regimes of pulsed operation as a function of absorber length to gain length ratio. Experimental measurements of the pulse time-domain characteristics over a wide range of operating temperatures are found to be in excellent agreement with analytical predictions. The impact of ridge waveguide design on the operational range is also examined and the key dimensions that most strongly impact efficient operation are identified. (topical review)

  15. Heterogeneous integration of thin film compound semiconductor lasers and SU8 waveguides on SiO2/Si

    Science.gov (United States)

    Palit, Sabarni; Kirch, Jeremy; Mawst, Luke; Kuech, Thomas; Jokerst, Nan Marie

    2010-02-01

    We present the heterogeneous integration of a 3.8 μm thick InGaAs/GaAs edge emitting laser that was metal-metal bonded to SiO2/Si and end-fire coupled into a 2.8 μm thick tapered SU8 polymer waveguide integrated on the same substrate. The system was driven in pulsed mode and the waveguide output was captured on an IR imaging array to characterize the mode. The waveguide output was also coupled into a multimode fiber, and into an optical head and spectrum analyzer, indicating lasing at ~997 nm and a threshold current density of 250 A/cm2.

  16. Reducing Threshold of Multi Quantum Wells InGaN Laser Diode by Using InGaN/GaN Waveguide

    Science.gov (United States)

    Abdullah, Rafid A.; Ibrahim, Kamarulazizi

    2010-07-01

    ISE TCAD (Integrated System Engineering Technology Computer Aided Design) software simulation program has been utilized to help study the effect of using InGaN/GaN as a waveguide instead of conventional GaN waveguide for multi quantum wells violet InGaN laser diode (LD). Simulation results indicate that the threshold of the LD has been reduced by using InGaN/GaN waveguide where InGaN/GaN waveguide increases the optical confinement factor which leads to increase the confinement carriers at the active region of the LD.

  17. Waveguide and active region structure optimization for low-divergence InAs/InGaAs quantum dot comb lasers

    Science.gov (United States)

    Korenev, Vladimir V.; Savelyev, Artem V.; Zhukov, Alexey E.; Maximov, Mikhail V.; Omelchenko, Alexander V.

    2015-05-01

    Ways to improve beam divergence and energy consumption of quantum dot lasers emitting via the ground-state optical transitions by optimization of the key parameters of laser active region are discussed. It is shown that there exist an optimal cavity length, dispersion of inhomogeneous broadening and number of QD layers in active region allowing to obtain lasing spectrum of a given width at minimum injection current. The planar dielectric waveguide of the laser is optimized by analytical means for a better trade-off between high Γ-factor and low beam divergence.

  18. Characteristics of the Single-Longitudinal-Mode Planar-Waveguide External Cavity Diode Laser at 1064 nm

    Science.gov (United States)

    Numata, Kenji; Alalusi, Mazin; Stolpner, Lew; Margaritis, Georgios; Camp, Jordan; Krainak, Michael

    2014-01-01

    We describe the characteristics of the planar-waveguide external cavity diode laser (PW-ECL). To the best of our knowledge, it is the first butterfly-packaged 1064 nm semiconductor laser that is stable enough to be locked to an external frequency reference. We evaluated its performance from the viewpoint of precision experiments. Using a hyperfine absorption line of iodine, we suppressed its frequency noise by a factor of up to 104 at 10 mHz. The PWECL's compactness and low cost make it a candidate to replace traditional Nd:YAG nonplanar ring oscillators and fiber lasers in applications that require a single longitudinal mode.

  19. Efficient Second Harmonic Generation in 3D Nonlinear Optical-Lattice-Like Cladding Waveguide Splitters by Femtosecond Laser Inscription.

    Science.gov (United States)

    Nie, Weijie; Jia, Yuechen; Vázquez de Aldana, Javier R; Chen, Feng

    2016-02-29

    Integrated photonic devices with beam splitting function are intriguing for a broad range of photonic applications. Through optical-lattice-like cladding waveguide structures fabricated by direct femtosecond laser writing, the light propagation can be engineered via the track-confined refractive index profiles, achieving tailored output beam distributions. In this work, we report on the fabrication of 3D laser-written optical-lattice-like structures in a nonlinear KTP crystal to implement 1 × 4 beam splitting. Second harmonic generation (SHG) of green light through these nonlinear waveguide beam splitter structures provides the capability for the compact visible laser emitting devices. With Type II phase matching of the fundamental wavelength (@ 1064 nm) to second harmonic waves (@ 532 nm), the frequency doubling has been achieved through this three-dimensional beam splitter. Under 1064-nm continuous-wave fundamental-wavelength pump beam, guided-wave SHG at 532 nm are measured with the maximum power of 0.65 mW and 0.48 mW for waveguide splitters (0.67 mW and 0.51 mW for corresponding straight channel waveguides), corresponding to a SH conversion efficiency of approximately ~14.3%/W and 13.9%/W (11.2%/W, 11.3%/W for corresponding straight channel waveguides), respectively. This work paves a way to fabricate compact integrated nonlinear photonic devices in a single chip with beam dividing functions.

  20. Surface-Emitting Distributed Feedback Terahertz Quantum-Cascade Lasers in Metal-Metal Waveguides

    Science.gov (United States)

    Kumar, Sushil; Williams, Benjamin S.; Qin, Qi; Lee, Alan W. M.; Hu, Qing; Reno, John L.

    2007-01-01

    Single-mode surface-emitting distributed feedback terahertz quantumcascade lasers operating around 2.9 THz are developed in metal-metal waveguides. A combination of techniques including precise control of phase of reflection at the facets, and u e of metal on the sidewalls to eliminate higher-order lateral modes allow robust single-mode operation over a range of approximately 0.35 THz. Single-lobed far-field radiation pattern is obtained using a pi phase-shift in center of the second-order Bragg grating. A grating device operating at 2.93 THz lased up to 149 K in pulsed mode and a temperature tuning of 19 .7 GHz was observed from 5 K to 147 K. The same device lased up to 78 K in continuous-wave (cw) mode emitting more than 6 m W of cw power at 5 K. ln general, maximum temperature of pulsed operation for grating devices was within a few Kelvin of that of multi-mode Fabry-Perot ridge lasers

  1. Theoretical study of annealed proton-exchanged Nd $LiNbO_{3}$ channel waveguide lasers with variational method

    CERN Document Server

    De Long Zhang; Yuan Guo Xie; Guilan, Ding; Yuming, Cui; Cai He Chen

    2001-01-01

    The controllable fabrication parameters, including anneal time, initial exchange time, channel width, dependences of TM/sub 00/ mode size, corresponding effective refractive index, effective pump area, and coupling efficiency between pump and laser modes in z-cut annealed proton-exchanged (APE) Nd:LiNbO/sub 3/ channel waveguide lasers were studied by using variational method. The effect of channel width on the surface index increment and the waveguide depth was taken into account. The features of mode size and effective refractive index were summarized, discussed, and compared with previously published experimental results. The effective pump area, which is directly proportional to threshold pump power, increases strongly, slightly, and very slightly with the increase of anneal time, channel width, and initial exchange time, respectively. However, the coupling efficiency, which is directly proportional to slope efficiency, remains constant (around 0.82) no matter what changes made to these parameters. The var...

  2. GHz modulation enabled using large extinction ratio waveguide-modulator integrated with 404 nm GaN laser diode

    KAUST Repository

    Shen, Chao; Lee, Changmin; Ng, Tien Khee; Speck, James S.; Nakamura, Shuji; DenBaars, Steven P.; Alyamani, Ahmed Y.; Eldesouki, Munir M.; Ooi, Boon S.

    2017-01-01

    A 404-nm emitting InGaN-based laser diode with integrated-waveguide-modulator showing a large extinction ratio of 11.3 dB was demonstrated on semipolar (2021) plane GaN substrate. The device shows a low modulation voltage of −2.5 V and ∼ GHz −3 dB bandwidth, enabling 1.7 Gbps data transmission.

  3. GHz modulation enabled using large extinction ratio waveguide-modulator integrated with 404 nm GaN laser diode

    KAUST Repository

    Shen, Chao

    2017-01-30

    A 404-nm emitting InGaN-based laser diode with integrated-waveguide-modulator showing a large extinction ratio of 11.3 dB was demonstrated on semipolar (2021) plane GaN substrate. The device shows a low modulation voltage of −2.5 V and ∼ GHz −3 dB bandwidth, enabling 1.7 Gbps data transmission.

  4. High-Power Dual-End-Pumped Actively Q-Switched Ho:YAG Ceramic Laser

    Science.gov (United States)

    Duan, Xiao-Ming; Yuan, Jin-He; Yao, Bao-Quan; Dai, Tong-Yu; Li, Jiang; Pan, Yu-Bai

    2015-10-01

    Not Available Supported by the National Natural Science Foundation of China under Grant Nos 61308009, 61405047 and 50990301, the China Postdoctoral Science Foundation Funded Project under Grant No 2015T80339, the Fundamental Research Funds for the Central Universities under Grant No HIT.NSRIF.2015042, and the Science Fund for Outstanding Youths of Heilongjiang Province under Grant No JQ201310.

  5. Nonlinear dynamics of solitary and optically injected two-element laser arrays with four different waveguide structures: a numerical study.

    Science.gov (United States)

    Li, Nianqiang; Susanto, H; Cemlyn, B R; Henning, I D; Adams, M J

    2018-02-19

    We study the nonlinear dynamics of solitary and optically injected two-element laser arrays with a range of waveguide structures. The analysis is performed with a detailed direct numerical simulation, where high-resolution dynamic maps are generated to identify regions of dynamic instability in the parameter space of interest. Our combined one- and two-parameter bifurcation analysis uncovers globally diverse dynamical regimes (steady-state, oscillation, and chaos) in the solitary laser arrays, which are greatly influenced by static design waveguiding structures, the amplitude-phase coupling factor of the electric field, i.e. the linewidth-enhancement factor, as well as the control parameter, e.g. the pump rate. When external optical injection is introduced to one element of the arrays, we show that the whole system can be either injection-locked simultaneously or display rich, different dynamics outside the locking region. The effect of optical injection is to significantly modify the nature and the regions of nonlinear dynamics from those found in the solitary case. We also show similarities and differences (asymmetry) between the oscillation amplitude of the two elements of the array in specific well-defined regions, which hold for all the waveguiding structures considered. Our findings pave the way to a better understanding of dynamic instability in large arrays of lasers.

  6. A field-deployable compound-specific isotope analyzer based on quantum cascade laser and hollow waveguide

    Science.gov (United States)

    Wu, Sheng; Deev, Andrei

    2013-01-01

    A field deployable Compound Specific Isotope Analyzer (CSIA) coupled with capillary chromatogrpahy based on Quantum Cascade (QC) lasers and Hollow Waveguide (HWG) with precision and chemical resolution matching mature Mass Spectroscopy has been achieved in our laboratory. The system could realize 0.3 per mil accuracy for 12C/13C for a Gas Chromatography (GC) peak lasting as short as 5 seconds with carbon molar concentration in the GC peak less than 0.5%. Spectroscopic advantages of HWG when working with QC lasers, i.e. single mode transmission, noiseless measurement and small sample volume, are compared with traditional free space and multipass spectroscopy methods.

  7. Engineering design of the interaction waveguide for high-power accelerator-driven microwave free-electron lasers

    International Nuclear Information System (INIS)

    Hopkins, D.B.; Clay, H.W.; Stallard, B.W.; Throop, A.L.; Listvinsky, G.; Makowski, M.A.

    1989-01-01

    Linear induction accelerators (LIAs) operating at beam energies of a few million electron volts and currents of a few thousand amperes are suitable drivers for free-electron lasers (FELs). Such lasers are capable of producing gigawatts of peak power and megawatts of average power at microwave frequencies. Such devices are being studied as possible power sources for future high-gradient accelerators and are being constructed for plasma heating applications. At high power levels, the engineering design of the interaction waveguide presents a challenge. This paper discusses several concerns, including electrical breakdown and metal fatigue limits, choice of material, and choice of operating propagation mode. 13 refs., 3 figs

  8. Sub-nanosecond periodically poled lithium niobate optical parametric generator and amplifier pumped by an actively Q-switched diode-pumped Nd:YAG microlaser

    Science.gov (United States)

    Liu, L.; Wang, H. Y.; Ning, Y.; Shen, C.; Si, L.; Yang, Y.; Bao, Q. L.; Ren, G.

    2017-05-01

    A sub-nanosecond seeded optical parametric generator (OPG) based on magnesium oxide-doped periodically poled lithium niobate (MgO:PPLN) crystal is presented. Pumped by an actively Q-switched diode-pumped 1 kHz, 1064 nm, Nd:YAG microlaser and seeded with a low power distributed feedback (DFB) diode continuous-wave (CW) laser, the OPG generated an output energy of 41.4 µJ and 681 ps pulse duration for the signal at 1652.4 nm, achieving a quantum conversion efficiency of 61.2% and a slope efficiency of 41.8%. Signal tuning was achieved from 1651.0 to 1652.4 nm by tuning the seed-laser current. The FWHM of the signal spectrum was approximately from 35 nm to 0.5 nm by injection seed laser. The SHG doubled the frequency of OPG signal to produce a output energy of 12 µJ with the energy conversion efficiency of 29.0% and tunanble wavelength near 826 nm.

  9. Observation and investigation of narrow optical transitions of 167Er3+ ions in femtosecond laser printed waveguides in 7LiYF4 crystal

    Science.gov (United States)

    Minnegaliev, M. M.; Dyakonov, I. V.; Gerasimov, K. I.; Kalinkin, A. A.; Kulik, S. P.; Moiseev, S. A.; Saygin, M. Yu; Urmancheev, R. V.

    2018-04-01

    We produced optical waveguides in the 167Er3+:7 LiYF4 crystal with diameters ranging from 30 to 100 μm by using the depressed-cladding approach with femtosecond laser. Stationary and coherent spectroscopy was performed on the 809 nm optical transitions between the hyperfine sublevels of 4I15/2 and 4I9/2 multiplets of 167Er3+ ions both inside and outside of waveguides. It was found that the spectra of 167Er3+ were slightly broadened and shifted inside the waveguides compared to the bulk crystal spectra. We managed to observe a two-pulse photon echo on this transition and determined phase relaxation times for each waveguide. The experimental results show that the created crystal waveguides doped by rare-earth ions can be used in optical quantum memory and integrated quantum schemes.

  10. High-modulation-efficiency, integrated waveguide modulator-laser diode at 448 nm

    KAUST Repository

    Shen, Chao; Ng, Tien Khee; Leonard, John T.; Pourhashemi, Arash; Oubei, Hassan M.; Alias, Mohd Sharizal; Nakamura, Shuji; DenBaars, Steven P.; Speck, James S.; Alyamani, Ahmed Y.; Eldesouki, Munir M.; Ooi, Boon S.

    2016-01-01

    To date, solid-state lighting (SSL), visible light communication (VLC) and optical clock generation functionalities in the blue-green color regime have been demonstrated based on discrete devices, including light-emitting diodes, laser diodes, and transverse-transmission modulators. This work presents the first integrated waveguide modulator-laser diode (IWM-LD) at 448 nm, offering the advantages of small-footprint, high-speed, and low power-consumption. A high modulation efficiency of 2.68 dB/V, deriving from a large extinction ratio of 9.4 dB and a low operating voltage range of 3.5 V, was measured. The electroabsorption characteristics revealed that the modulation effect, as observed from the red-shifting of the absorption edge, was resulted from the external-field-induced quantum-confined-Stark-effect (QCSE). A comparative analysis of the photocurrent versus wavelength spectra in semipolar- and polar-plane InGaN/GaN quantum wells (QWs) confirmed that the IWM-LD based on semipolar (20¯2 ¯1) QWs was able to operate in a manner similar to other III-V materials typically used in optical telecommunications, due to the reduced piezoelectric field. Utilizing the integrated modulator, a -3dB bandwidth of ~1 GHz was measured, and a data rate of 1 Gbit/s was demonstrated using on-off keying (OOK) modulation. Our experimental investigation highlighted the advantage of implementing the IWM-LD on the same semipolar QW epitaxy in enabling a high-efficiency platform for SSL-VLC dual-functionalities.

  11. High-modulation-efficiency, integrated waveguide modulator-laser diode at 448 nm

    KAUST Repository

    Shen, Chao

    2016-01-25

    To date, solid-state lighting (SSL), visible light communication (VLC) and optical clock generation functionalities in the blue-green color regime have been demonstrated based on discrete devices, including light-emitting diodes, laser diodes, and transverse-transmission modulators. This work presents the first integrated waveguide modulator-laser diode (IWM-LD) at 448 nm, offering the advantages of small-footprint, high-speed, and low power-consumption. A high modulation efficiency of 2.68 dB/V, deriving from a large extinction ratio of 9.4 dB and a low operating voltage range of 3.5 V, was measured. The electroabsorption characteristics revealed that the modulation effect, as observed from the red-shifting of the absorption edge, was resulted from the external-field-induced quantum-confined-Stark-effect (QCSE). A comparative analysis of the photocurrent versus wavelength spectra in semipolar- and polar-plane InGaN/GaN quantum wells (QWs) confirmed that the IWM-LD based on semipolar (20¯2 ¯1) QWs was able to operate in a manner similar to other III-V materials typically used in optical telecommunications, due to the reduced piezoelectric field. Utilizing the integrated modulator, a -3dB bandwidth of ~1 GHz was measured, and a data rate of 1 Gbit/s was demonstrated using on-off keying (OOK) modulation. Our experimental investigation highlighted the advantage of implementing the IWM-LD on the same semipolar QW epitaxy in enabling a high-efficiency platform for SSL-VLC dual-functionalities.

  12. Generation of Bright, Spatially Coherent Soft X-Ray High Harmonics in a Hollow Waveguide Using Two-Color Synthesized Laser Pulses.

    Science.gov (United States)

    Jin, Cheng; Stein, Gregory J; Hong, Kyung-Han; Lin, C D

    2015-07-24

    We investigate the efficient generation of low-divergence high-order harmonics driven by waveform-optimized laser pulses in a gas-filled hollow waveguide. The drive waveform is obtained by synthesizing two-color laser pulses, optimized such that highest harmonic yields are emitted from each atom. Optimization of the gas pressure and waveguide configuration has enabled us to produce bright and spatially coherent harmonics extending from the extreme ultraviolet to soft x rays. Our study on the interplay among waveguide mode, atomic dispersion, and plasma effect uncovers how dynamic phase matching is accomplished and how an optimized waveform is maintained when optimal waveguide parameters (radius and length) and gas pressure are identified. Our analysis should help laboratory development in the generation of high-flux bright coherent soft x rays as tabletop light sources for applications.

  13. Short-cavity DBR laser using an InP/InGaAsP deep-ridge waveguide with vertical-groove gratings

    NARCIS (Netherlands)

    Segawa, T.; Docter, B.; Kakitsuka, T.; Matsuo, S.; Ishii, T.; Kawaguchi, Y.; Kondo, Y.; Karouta, F.; Smit, M.K.; Suzuki, H.

    2007-01-01

    A compact distributed Bragg reflector (DBR) laser was fabricated using an InP/InGaAsP deep-ridge waveguide with vertical-groove gratings. We achieved stable single-mode laser operation with an active length of only 25-µm with low threshold current.

  14. Extremely wide lasing bandwidth from InAs/InP quantumdash ridge-waveguide laser near 1.6 μm

    KAUST Repository

    Khan, Mohammed Zahed Mustafa; Ng, Tien Khee; Lee, Chisen; Bhattacharya, Pallab K.; Ooi, Boon S.

    2013-01-01

    We demonstrate an ultra-broad lasing bandwidth (-3dB) of > 50 nm utilizing InAs/InGaAlAs/InP quantum-dash ridge-waveguide laser using chirped AlGaInAs barrier layer thickness. Our device exhibits a recorded bandwidth and significant improvement of laser characteristics

  15. Efficient and ultra-narrow-linewidth integrated waveguide lasers in Al2O3:Yb and Al2O3:Er

    NARCIS (Netherlands)

    Bernhardi, Edward; van Wolferen, Hendricus A.G.M.; Worhoff, Kerstin; de Ridder, R.M.; Pollnau, Markus

    The ability to integrate Bragg grating structures with optical waveguides provides the opportunity to realize a variety of compact monolithic optical devices, such as distributed feedback (DFB) lasers, and distributed Bragg reflector (DBR) lasers. In this work, we report passive DBR cavities with

  16. An experimental analysis of the waveguide modes in a high-gain free-electron laser amplifier

    International Nuclear Information System (INIS)

    Anderson, B.R.

    1989-01-01

    The presence, growth, and interaction of transverse waveguide modes in high-gain free-electron laser (FEL) amplifiers has been observed and studied. Using the Electron Laser Facility at Lawrence Livermore National Laboratory, a 3 MeV, 800 A electron beam generated by the Experimental Test Accelerator was injected into a planar wiggler. Power was then extracted and measured in the fundamental (TE 01 ) an higher-order modes (Te 21 and TM 21 ) under various sets of operating conditions. Horizontal focusing through the wiggler was provided by external quadrupole magnets. There was no axial guide field. The input microwave signal for amplification was generated by a 100 kW magnetron operating at 34.6 Ghz. Power measurements were taken for both flat and tapered wigglers, for two sizes of waveguide, and for both flat and tapered wigglers, for two sizes of waveguide, and for both fundamental and higher mode injection. Mode content was determined by sampling the radiated signal at specific points in the radiation patter. For the flat wiggler and with the large waveguide (2.9 cm x 9.8 cm) the power in the higher modes was comparable to power in the fundamental. both exhibited gains greater than 30 dB/m prior to saturation and both reached powers in excess of 80 MW. Choice of injection mode had little effect on the operation of the system. Operation with the smaller guide (WR-229) provided much better mode selectivity. The fundamental mode continued to show optimum gain in excess of 30 dB/m while the higher-mode gain was of order 20 dB/m. As expected, power output increased significantly with the tapered wigglers. The relative mode content depended on the specific taper used

  17. Experimental and theoretical analysis of the dominant lateral waveguiding mechanism in 975 nm high power broad area diode lasers

    International Nuclear Information System (INIS)

    Crump, P; Böldicke, S; Schultz, C M; Ekhteraei, H; Wenzel, H; Erbert, G

    2012-01-01

    For maximum fibre-coupled power, high power broad area diode lasers must operate with small lateral far field angles at high continuous wave (CW) powers. However, these structures are laterally multi-moded, with low beam quality and wide emission angles. In order to experimentally determine the origin of the low beam quality, spectrally resolved near and far field measurements were performed for a diode laser with 50 µm stripe width. Within the range measured (CW optical output powers to 1.5 W) the laser is shown to operate in just six stable lateral modes, with spatially periodic profiles. Comparisons of the measured profiles with the results of two-dimensional modal simulation demonstrate that current-induced thermal lensing dominates the lateral waveguiding, in spite of the presence of both strong built-in index guiding and gain guiding. No evidence is seen for filamentation. Building on the diagnosis, proposals are presented for improvements to beam quality. (paper)

  18. UV laser-induced high resolution cleaving of Si wafers for micro-nano devices and polymeric waveguide characterization

    International Nuclear Information System (INIS)

    Casquel, R.; Holgado, M.; Garcia-Ballesteros, J.J.; Zinoviev, K.; Fernandez-Sanchez, C.; Sanza, F.J.; Molpeceres, C.; Laguna, M.F.; Llobera, A.; Ocana, J.L.; Dominguez, C.

    2011-01-01

    In this work we propose a method for cleaving silicon-based photonic chips by using a laser based micromachining system, consisting of a ND:YVO 4 laser emitting at 355 nm in nanosecond pulse regime and a micropositioning system. The laser makes grooved marks placed at the desired locations and directions where cleaves have to be initiated, and after several processing steps, a crack appears and propagate along the crystallographic planes of the silicon wafer. This allows cleavage of the chips automatically and with high positioning accuracy, and provides polished vertical facets with better quality than the obtained with other cleaving process, which eases the optical characterization of photonic devices. This method has been found to be particularly useful when cleaving small-sized chips, where manual cleaving is hard to perform; and also for polymeric waveguides, whose facets get damaged or even destroyed with polishing or manual cleaving processing. Influence of length of the grooved line and speed of processing is studied for a variety of silicon chips. An application for cleaving and characterizing sol-gel waveguides is presented. The total amount of light coupled is higher than when using any other procedure.

  19. UV laser-induced high resolution cleaving of Si wafers for micro-nano devices and polymeric waveguide characterization

    Energy Technology Data Exchange (ETDEWEB)

    Casquel, R., E-mail: rafael.casquel@upm.es [Centro Laser UPM, Universidad Politecnica de Madrid, Campus Sur UPM, 28031 Madrid (Spain); Holgado, M.; Garcia-Ballesteros, J.J. [Centro Laser UPM, Universidad Politecnica de Madrid, Campus Sur UPM, 28031 Madrid (Spain); Zinoviev, K.; Fernandez-Sanchez, C. [Instituto de Microelectronica de Barcelona, Centro Nacional de Microelectronica - CSIC, Campus Universidad Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Sanza, F.J.; Molpeceres, C.; Laguna, M.F. [Centro Laser UPM, Universidad Politecnica de Madrid, Campus Sur UPM, 28031 Madrid (Spain); Llobera, A. [Instituto de Microelectronica de Barcelona, Centro Nacional de Microelectronica - CSIC, Campus Universidad Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Ocana, J.L. [Centro Laser UPM, Universidad Politecnica de Madrid, Campus Sur UPM, 28031 Madrid (Spain); Dominguez, C. [Instituto de Microelectronica de Barcelona, Centro Nacional de Microelectronica - CSIC, Campus Universidad Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)

    2011-04-01

    In this work we propose a method for cleaving silicon-based photonic chips by using a laser based micromachining system, consisting of a ND:YVO{sub 4} laser emitting at 355 nm in nanosecond pulse regime and a micropositioning system. The laser makes grooved marks placed at the desired locations and directions where cleaves have to be initiated, and after several processing steps, a crack appears and propagate along the crystallographic planes of the silicon wafer. This allows cleavage of the chips automatically and with high positioning accuracy, and provides polished vertical facets with better quality than the obtained with other cleaving process, which eases the optical characterization of photonic devices. This method has been found to be particularly useful when cleaving small-sized chips, where manual cleaving is hard to perform; and also for polymeric waveguides, whose facets get damaged or even destroyed with polishing or manual cleaving processing. Influence of length of the grooved line and speed of processing is studied for a variety of silicon chips. An application for cleaving and characterizing sol-gel waveguides is presented. The total amount of light coupled is higher than when using any other procedure.

  20. Direct laser writing of a low-loss waveguide with independent control over the transverse dimension and the refractive index contrast between the core and the cladding.

    Science.gov (United States)

    Masselin, Pascal; Bychkov, Eugène; Coq, David Le

    2016-08-01

    In this Letter, we present the realization of a low-loss waveguide in a chalcogenide glass by direct laser writing technique in a particular configuration that allows the independent control over the diameter of the core and the magnitude of the refractive index contrast with the cladding. The waveguide is of multicore type and composed of 19 channels arranged on a hexagonal lattice. Each channel is obtained by stacking voxels of refractive index variation obtained by static exposure to femtosecond laser pulse burst. The distance between the channels can be used to vary the diameter of the waveguide, while the duration of laser burst controls the magnitude of the effective index and the propagation loss. We demonstrate that it can be reduced down to 0.11 dB/cm.

  1. Densification behavior, doping profile and planar waveguide laser performance of the tape casting YAG/Nd:YAG/YAG ceramics

    Science.gov (United States)

    Ge, Lin; Li, Jiang; Qu, Haiyun; Wang, Juntao; Liu, Jiao; Dai, Jiawei; Zhou, Zhiwei; Liu, Binglong; Kou, Huamin; Shi, Yun; Wang, Zheng; Pan, Yubai; Gao, Qingsong; Guo, Jingkun

    2016-10-01

    The sintering behavior and doping concentration profile of the planar waveguide YAG/Nd:YAG/YAG ceramics by the tape casting and solid-state reaction method were investigated on the basis of densification trajectory, microstructure evolution, and Nd3+ ions diffusion. The porosity of the green body by tape casting and cold isostatic pressing is about 38.6%. And the green bodies were consolidated from 1100 °C to 1800 °C for 0.5-20 h to study the densification and the doping diffusion behaviors. At the temperature higher than 1500 °C, pure YAG phase is formed, followed by the densification and grain growth process. With the increase of temperature, two sintering stages occur, corresponding to remarkable densification and significant grain growth, respectively. The mechanism controlling densification at 1550 °C is grain boundary diffusion. The diffusion of Nd3+ ions is more sensitive to temperature than the sintering time, and the minimum temperature required for the obvious diffusion of Nd3+ ions is higher than 1700 °C. Finally, planar waveguide YAG/1.5 at.%Nd:YAG/YAG transparent ceramics with in-line transmittance of 84.8% at 1064 nm were obtained by vacuum-sintering at 1780 °C for 30 h. The fluorescence lifetime of 4F3/2 state of Nd3+ in the specimen is about 259 μs. The prepared ceramic waveguide was tested in a laser amplifier and the laser pulse was amplificated from 87 mJ to 238 mJ, with the pump energy of 680 mJ.

  2. Low-loss 3D-laser-written mid-infrared LiNbO3 depressed-index cladding waveguides for both TE and TM polarizations.

    Science.gov (United States)

    Nguyen, Huu-Dat; Ródenas, Airán; Vázquez de Aldana, Javier R; Martín, Guillermo; Martínez, Javier; Aguiló, Magdalena; Pujol, Maria Cinta; Díaz, Francesc

    2017-02-20

    We report mid-infrared LiNbO3 depressed-index microstructured cladding waveguides fabricated by three-dimensional laser writing showing low propagation losses (~1.5 dB/cm) at 3.68 µm wavelength for both the transverse electric and magnetic polarized modes, a feature previously unachieved due to the strong anisotropic properties of this type of laser microstructured waveguides and which is of fundamental importance for many photonic applications. Using a heuristic modeling-testing iteration design approach which takes into account cladding induced stress-optic index changes, the fabricated cladding microstructure provides low-loss single mode operation for the mid-IR for both orthogonal polarizations. The dependence of the localized refractive index changes within the cladding microstructure with post-fabrication thermal annealing processes was also investigated, revealing its complex dependence of the laser induced refractive index changes on laser fabrication conditions and thermal post-processing steps. The waveguide modes properties and their dependence on thermal post-processing were numerically modeled and fitted to the experimental values by systematically varying three fundamental parameters of this type of waveguides: depressed refractive index values at sub-micron laser-written tracks, track size changes, and piezo-optic induced refractive index changes.

  3. A compact O-plus C-band switchable quad-wavelength fiber laser using arrayed waveguide grating

    International Nuclear Information System (INIS)

    Latif, A A; Zulkifli, M Z; Hassan, N A; Ahmad, H; Harun, S W; Ghani, Z A

    2010-01-01

    In this paper, a design of a quad-wavelength fiber laser (QWFL) operating in two different regions namely the O-band covering from 1302 nm to1317.4 nm and C-band from 1530.5 nm to 1548.0 nm is presented. Two different ASE sources from semiconductor optical amplifiers (SOAs) are used, one at 1310 nm and the other at1550 nm. By using a 1×24 channels arrayed waveguide grating (AWG) with 100 GHz interchannel spacing, the system is capable of generating 24 different wavelengths in more than 24 ways of quad-wavelength fiber laser with 0.6 nm and 0.8 nm of interval channel for O-band and C-band regions, respectively

  4. Active Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Ek, Sara

    This thesis deals with the fabrication and characterization of active photonic crystal waveguides, realized in III-V semiconductor material with embedded active layers. The platform offering active photonic crystal waveguides has many potential applications. One of these is a compact photonic...... due to photonic crystal dispersion. The observations are explained by the enhancement of net gain by light slow down. Another application based on active photonic crystal waveguides is micro lasers. Measurements on quantum dot micro laser cavities with different mirror configurations and photonic...

  5. Femtosecond laser microfabrication of optical waveguides in commercial microfluidic lab-on-a-chip

    NARCIS (Netherlands)

    Osellame, R.; Martinez-Vazquez, R.; Ramponi, R.; Cerullo, G.; Dongre, C.; Dekker, R.; Hoekstra, Hugo; Pollnau, Markus

    One of the main challenges of lab-on-a-chip technology is the on-chip integration of photonic functionalities by manufacturing optical waveguides for sensing biomolecules flowing in the microchannels. Such integrated approach has many advantages over traditional free-space optical sensing, such as

  6. Bragg-grating-based rare-earth-ion-doped channel waveguide lasers and their applications

    NARCIS (Netherlands)

    Bernhardi, Edward

    2012-01-01

    The research presented in this thesis concerns the investigation and development of Bragggrating-based integrated cavities for the rare-earth-ion-doped Al2O3 (aluminium oxide) waveguide platform, both from a theoretical and an experimental point of view, with the primary purpose of realizing

  7. Conductive graphene as passive saturable absorber with high instantaneous peak power and pulse energy in Q-switched regime

    Science.gov (United States)

    Zuikafly, Siti Nur Fatin; Khalifa, Ali; Ahmad, Fauzan; Shafie, Suhaidi; Harun, SulaimanWadi

    2018-06-01

    The Q-switched pulse regime is demonstrated by integrating conductive graphene as passive saturable absorber producing relatively high instantaneous peak power and pulse energy. The fabricated conductive graphene is investigated using Raman spectroscopy. The single wavelength Q-switching operates at 1558.28 nm at maximum input pump power of 151.47 mW. As the pump power is increased from threshold power of 51.6 mW to 151.47 mW, the pulse train repetition rate increases proportionally from 47.94 kHz to 67.8 kHz while the pulse width is reduced from 9.58 μs to 6.02 μs. The generated stable pulse produced maximum peak power and pulse energy of 32 mW and 206 nJ, respectively. The first beat node of the measured signal-to-noise ratio is about 62 dB indicating high pulse stability.

  8. Third-order optical nonlinearities in bulk and fs-laser inscribed waveguides in strengthened alkali aluminosilcate glass

    Science.gov (United States)

    Almeida, Gustavo F. B.; Almeida, Juliana M. P.; Martins, Renato J.; De Boni, Leonardo; Arnold, Craig B.; Mendonca, Cleber R.

    2018-01-01

    The development of advanced photonics devices requires materials with large optical nonlinearities, fast response times and high optical transparency, while at the same time allowing for the micro/nano-processing needed for integrated photonics. In this context, glasses have been receiving considerable attention given their relevant optical properties which can be specifically tailored by compositional control. Corning Gorilla® Glass (strengthened alkali aluminosilicate glass) is well-known for its use as a protective screen in mobile devices, and has attracted interest as a potential candidate for optical devices. Therefore, it is crucial not only to expand the knowledge on the fabrication of waveguides in Gorilla Glass under different regimes, but also to determine its nonlinear optical response, both using fs-laser pulses. Thus, this paper reports, for the first time, characterization of the third-order optical nonlinearities of Gorilla Glass, as well as linear and nonlinear characterization of waveguide written with femtosecond pulses under the low repetition rate regime (1 kHz).

  9. Changes induced in a ZnS:Cr-based electroluminescent waveguide structure by intrinsic near-infrared laser radiation

    International Nuclear Information System (INIS)

    Vlasenko, N. A.; Oleksenko, P. F.; Mukhlyo, M. A.; Veligura, L. I.

    2013-01-01

    The causes of changes that occur in a thin-film electroluminescent metal-insulator-semiconductor-insulator-metal waveguide structure based on ZnS:Cr (Cr concentration of ∼4 × 10 20 cm −3 ) upon lasing (λ ≈ 2.6 μm) and that induce lasing cessation are studied. It is established that lasing ceases because of light-scattering inhomogeneities formed in the structure and, hence, optical losses enhance. The origin of the inhomogeneities and the causes of their formation are clarified by studying the surface topology and the crystal structure of constituent layers of the samples before and after lasing. The studies are performed by means of atomic force microscopy and X-ray radiography. It is shown that a substantial increase in the sizes of grains on the surface of the structure is the manifestation of changes induced in the ZnS:Cr film by recrystallization. Recrystallization is initiated by local heating by absorbed laser radiation in existing Cr clusters and quickened by a strong electric field (>1 MV cm −1 ). The changes observed in the ZnS:Cr film are as follows: the textured growth of ZnS crystallites, an increase in the content of Cr clusters, and the appearance of some CrS and a rather high ZnO content. Some ways for improving the stability of lasing in the ZnS:Cr-based waveguide structures are proposed

  10. The role of the gas/plasma plume and self-focusing in a gas-filled capillary discharge waveguide for high-power laser-plasma applications

    CERN Document Server

    Ciocarlan, C.; Islam, M. R.; Ersfeld, B.; Abuazoum, S.; Wilson, R.; Aniculaesei, C.; Welsh, G. H.; Vieux, G.; Jaroszynski, D. A.; 10.1063/1.4822333

    2013-01-01

    The role of the gas/plasma plume at the entrance of a gas-filled capillary discharge plasma waveguide in increasing the laser intensity has been investigated. Distinction is made between neutral gas and hot plasma plumes that, respectively, develop before and after discharge breakdown. Time-averaged measurements show that the on-axis plasma density of a fully expanded plasma plume over this region is similar to that inside the waveguide. Above the critical power, relativistic and ponderomotive selffocusing lead to an increase in the intensity, which can be nearly a factor of 2 compared with the case without a plume. When used as a laser plasma wakefield accelerator, the enhancement of intensity can lead to prompt electron injection very close to the entrance of the waveguide. Self-focusing occurs within two Rayleigh lengths of the waveguide entrance plane in the region, where the laser beam is converging. Analytical theory and numerical simulations show that, for a density of 3.01018 cm3, the peak normalized...

  11. Semipolar III–nitride quantum well waveguide photodetector integrated with laser diode for on-chip photonic system

    KAUST Repository

    Shen, Chao

    2017-02-28

    A high-performance waveguide photodetector (WPD) integrated with a laser diode (LD) sharing the single InGaN/GaN quantum well active region is demonstrated on a semipolar GaN substrate. The photocurrent of the integrated WPD is effectively tuned by the emitted optical power from the LD. The responsivity ranges from 0.018 to 0.051 A/W with increasing reverse bias from 0 to 10 V. The WPD shows a large 3 dB modulation bandwidth of 230 MHz. The integrated device, being used for power monitoring and on-chip communication, paves the way towards the eventual realization of a III–nitride on-chip photonic system.

  12. Semipolar III–nitride quantum well waveguide photodetector integrated with laser diode for on-chip photonic system

    KAUST Repository

    Shen, Chao; Lee, Changmin; Stegenburgs, Edgars; Lerma, Jorge Holguin; Ng, Tien Khee; Nakamura, Shuji; DenBaars, Steven P.; Alyamani, Ahmed Y.; El-Desouki, Munir M.; Ooi, Boon S.

    2017-01-01

    A high-performance waveguide photodetector (WPD) integrated with a laser diode (LD) sharing the single InGaN/GaN quantum well active region is demonstrated on a semipolar GaN substrate. The photocurrent of the integrated WPD is effectively tuned by the emitted optical power from the LD. The responsivity ranges from 0.018 to 0.051 A/W with increasing reverse bias from 0 to 10 V. The WPD shows a large 3 dB modulation bandwidth of 230 MHz. The integrated device, being used for power monitoring and on-chip communication, paves the way towards the eventual realization of a III–nitride on-chip photonic system.

  13. Design and Development of Intracavity Optical Parametric Oscillator-based Eye Safe Laser Operating at 20 Hz without Forced Air Cooling

    OpenAIRE

    Atul Bhardwaj; Lalita Agrawal; A. K. Maini

    2013-01-01

    In this paper we report the design and development of an electro-optically Q-switched diode pumped Nd:YAG laser with intracavity optical parametric oscillator, generating ~ 5 ns laser pulses of ~8 mJ energy at eye safe wavelength of 1534 nm. A Z-shaped laser resonator has been designed with porro prism end reflector in Q-switch arm containing RTP Q-Switch and a suitably oriented waveplate. The gain arm consists of a Ø3 x 72 mm Nd: YAG laser rod, pumped from one side by 3 x 5 bar laser diode a...

  14. Improvements of the ruby laser oscillator system for laser scattering

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Kumagai, Katsuaki; Kawakami, Tomohide; Matoba, Tohru; Funahashi, Akimasa

    1978-10-01

    A ruby laser oscillator system is used to measure electron temperatures of the Tokamak plasmas(JFT-2 and JFT-2a). Improvements have been made of the laser oscillator to obtain the correct values. Described are the improvements and the damages of a ruby rod and a KD*P crystal for Q-switching by laser beam. Improvement are the linear Xe lamp replaced by a helical Xe lamp and in the electrical circuit for Q-switching. The damage of an optical component by a laser beam should be clarified from the damage data; the cause is not found yet. (author)

  15. Fully relativistic free-electron laser in a completely filled waveguide

    International Nuclear Information System (INIS)

    Farokhi, B.; Abdykian, A.

    2005-01-01

    An analysis of the azimuthally symmetrical, high frequency eigenmodes of a cylindrical metallic waveguide completely filled with a relativistic magnetized plasma is presented. A relativistic nonlinear wave equation is derived in a form which includes the coupling of EH and HE modes due to the finite axial magnetic field. Relativistic equations that permit calculation of the dispersion curves for four families of electromagnetic and electrostatic modes are derived. Numerical analysis is conducted to study the relativistic dispersion curves of various modes as a function of axial magnetic field B 0 . This treatment is shown that the dispersion curves dependent to γ in low frequency which is ignored in previous work. It is found that in drawn figures shown difference between relativistic and non-relativistic cases. The former each figure is treated for two orbit groups. This study is benefiting to facilities the development of devices for generation of high-power electromagnetic radiation, charged particle acceleration, and other applications of plasma waveguide. (author)

  16. Turnable Semiconductor Laser Spectroscopy in Hollow Optical Waveguides, Phase II SBIR

    Energy Technology Data Exchange (ETDEWEB)

    Gregory J. Fetzer, Ph.D.

    2001-12-24

    In this study a novel optical trace gas sensor based on a perforated hollow waveguide (PHW) was proposed. The sensor has been given the acronym ESHOW for Environmental Sensor using Hollow Optical Waveguides. Realizations of the sensor have demonstrated rapid response time (<2s), low minimum detection limits (typically around 3 x 10-5 absorbance). Operation of the PHW technology has been demonstrated in the near-infrared (NIR) and mid0infrared (MIR) regions of the spectrum. Simulation of sensor performance provided in depth understanding of the signals and signal processing required to provide high sensitivity yet retain rapid response to gas changes. A dedicated sensor electronics and software foundation were developed during the course of the Phase II effort. Commercial applications of the sensor are ambient air and continuous emissions monitoring, industrial process control and hazardous waste site monitoring. There are numerous other applications for such a sensor including medical diagnosis and treatment, breath analysis for legal purposes, water quality assessment, combustion diagnostics, and chemical process control. The successful completion of Phase II resulted in additional funding of instrument development by the Nations Institute of Heath through a Phase I SBIR grant and a strategic teaming relationship with a commercial manufacture of medical instrumentation. The purpose of the NIH grant and teaming relationship is to further develop the sensor to monitor NO in exhaled breath for the purposes of asthma diagnosis.

  17. Hollow waveguide cavity ringdown spectroscopy

    Science.gov (United States)

    Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

    2012-01-01

    Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

  18. New CO2 laser waveguide systems: advances in surgery of tracheal stenosis

    Science.gov (United States)

    Stasche, Norbert; Bernecker, Frank; Hoermann, Karl

    1996-01-01

    The carbon dioxide laser is a well established tool in the surgical treatment of laryngeal and tracheal stenosis. Usually the laser beam is applied by a microscope/micromanipulator device. Different types of rigid laryngoscopes and bronchoscopes provide access to nearly every area of larynx, trachea and main bronchi. In order to be treated with this equipment the target tissue has to be in a straight optical axis with the laser beam output at the micromanipulator. We report about one patient who presented with severe dyspnea due to granulation tissue directly below his left vocal cord. He was suffering from tracheomalacia for several years and was successfully treated by tracheostomy and a Montgomery's silicone T-tube as a stent. Then granulation tissue blocked the upper orifice of the Montgomery's T-tube. First removal by a carbon dioxide laser beam through the laryngoscope would have required sacrificing his intact left vocal cord. We removed the obstructing tissue by using the ArthroLaseTM System: the carbon dioxide laser beam was conducted through a 90 degree bent rigid probe, using the tracheostomy as an access. This ArthroLaseTM System was originally designed for arthroscopic surgery. In this special case however it successfully extends the use of the carbon dioxide laser in otolaryngology.

  19. Diode-laser pumping into the emitting level for efficient lasing of depressed cladding waveguides realized in Nd:YVO4 by the direct femtosecond-laser writing technique.

    Science.gov (United States)

    Pavel, Nicolaie; Salamu, Gabriela; Jipa, Florin; Zamfirescu, Marian

    2014-09-22

    Depressed cladding waveguides have been realized in Nd:YVO(4) employing direct writing technique with a femtosecond-laser beam. It was shown that the output performances of such laser devices are improved by the reduction of the quantum defect between the pump wavelength and the laser wavelength. Thus, under the classical pump at 808 nm (i.e. into the (4)F(5/2) level), a 100-μm diameter circular waveguide inscribed in a 0.7-at.% Nd:YVO(4) outputted 1.06-μm laser pulses with 3.0-mJ energy, at 0.30 optical efficiency and slope efficiency of 0.32. The pump at 880 nm (i.e.directly into the (4)F(3/2) emitting level) increased the pulse energy at 3.8 mJ and improved both optical efficiency and slope efficiency at 0.36 and 0.39, respectively. The same waveguide yielded continuous-wave 1.5-W output power at 1.06 μm under the pump at 880 nm. Laser emission at 1.34 μm was also improved using the pump into the (4)F(3/2) emitting level of Nd:YVO(4).

  20. Dynamics of a gain-switched distributed feedback ridge waveguide laser in nanoseconds time scale under very high current injection conditions.

    Science.gov (United States)

    Klehr, A; Wenzel, H; Brox, O; Schwertfeger, S; Staske, R; Erbert, G

    2013-02-11

    We present detailed experimental investigations of the temporal, spectral and spatial behavior of a gain-switched distributed feedback (DFB) laser emitting at a wavelength of 1064 nm. Gain-switching is achieved by injecting nearly rectangular shaped current pulses having a length of 50 ns and a very high amplitude up to 2.5 A. The repetition frequency is 200 kHz. The laser has a ridge waveguide (RW) for lateral waveguiding with a ridge width of 3 µm and a cavity length of 1.5 mm. Time resolved investigations show, depending on the amplitude of the current pulses, that the optical power exhibits different types of oscillatory behavior during the pulses, accompanied by changes in the lateral near field intensity profiles and optical spectra. Three different types of instabilities can be distinguished: mode beating with frequencies between 25 GHz and 30 GHz, switching between different lateral intensity profiles with a frequency of 0.4 GHz and self-sustained oscillations with a frequency of 4 GHz. The investigations are of great relevance for the utilization of gain-switched DFB-RW lasers as seed lasers for fiber laser systems and in other applications, which require a high optical power.

  1. Ammonia detection using hollow waveguide enhanced laser absorption spectroscopy based on a 9.56 μm quantum cascade laser

    Science.gov (United States)

    Li, Jinyi; Yang, Sen; Wang, Ruixue; Du, Zhenhui; Wei, Yingying

    2017-10-01

    Ammonia (NH3) is the most abundant alkalescency trace gas in the atmosphere having a foul odor, which is produced by both natural and anthropogenic sources. Chinese Emission Standard for Odor Pollutants has listed NH3 as one of the eight malodorous pollutants since 1993, specifying the emission concentration less than 1 mg/m3 (1.44ppmv). NH3 detection continuously from ppb to ppm levels is significant for protection of environmental atmosphere and safety of industrial and agricultural production. Tunable laser absorption spectroscopy (TLAS) is an increasingly important optical method for trace gas detection. TLAS do not require pretreatment and accumulation of the concentration of the analyzed sample, unlike, for example, more conventional methods such as mass spectrometry or gas chromatography. In addition, TLAS can provide high precision remote sensing capabilities, high sensitivities and fast response. Hollow waveguide (HWG) has recently emerged as a novel concept serving as an efficient optical waveguide and as a highly miniaturized gas cell. Among the main advantages of HWG gas cell compared with conventional multi-pass gas cells is the considerably decreased sample which facilitates gas exchanging. An ammonia sensor based on TLAS using a 5m HWG as the gas cell is report here. A 9.56μm, continuous-wave, distributed feed-back (DFB), room temperature quantum cascade laser (QCL), is employed as the optical source. The interference-free NH3 absorption line located at 1046.4cm-1 (λ 9556.6nm) is selected for detection by analyzing absorption spectrum from 1045-1047 cm-1 within the ν2 fundamental absorption band of ammonia. Direct absorption spectroscopy (DAS) technique is utilized and the measured spectral line is fitted by a simulation model by HITRAN database to obtain the NH3 concentration. The sensor performance is tested with standard gas and the result shows a 1σ minimum detectable concentration of ammonia is about 200 ppb with 1 sec time resolution

  2. Effect of optical waveguiding mechanism on the lasing action of chirped InAs/AlGaInAs/InP quantum dash lasers

    KAUST Repository

    Khan, Mohammed Zahed Mustafa

    2013-03-04

    We report on the atypical emission dynamics of InAs/AlGaInAs/InP quantum dash (Qdash) lasers employing varying AlGaInAs barrier thickness (multilayer-chirped structure). The analysis is carried out via fabry-perot (FP) ridge (RW) and stripe waveguide (SW) laser characterization corresponding to the index and gain guided waveguiding mechanisms, respectively, and at different current pulse width operations. The laser emissions are found to emerge from the size dispersion of the Qdash ensembles across the four Qdash-barrier stacks, and governed by their overlapping quasi-zero dimensional density of states (DOS). The spectral characteristics demonstrated prominent dependence on the waveguiding mechanism at quasi-continuous wave (QCW) operation (long pulse width). The RW geometry showed unusual spectral split in the emission spectra on increasing current injection while the SW geometry showed typical broadening of lasing spectra. These effects were attributed to the highly inhomogeneous active region, the nonequilibrium carrier distribution and the energy exchange between Qdash groups across the Qdash-barrier stacks. Furthermore, QCW operation showed a progressive red shift of emission spectra with injection current, resulted from active region heating and carrier depopulation, which was observed to be minimal in the short pulse width (SPW) operation. Our investigation sheds light on the device physics of chirped Qdash laser structure and provides guidelines for further optimization in obtaining broad-gain laser diodes. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  3. Analysis of waveguide architectures of InGaN/GaN diode lasers by nearfield optical microscopy

    Science.gov (United States)

    Friede, Sebastian; Tomm, Jens W.; Kühn, Sergei; Hoffmann, Veit; Wenzel, Hans

    2017-02-01

    Waveguide (WG) architectures of 420-nm emitting InAlGaN/GaN diode lasers are analyzed by photoluminescence (PL) and photocurrent (PC) spectroscopy using a nearfield scanning optical microscope (NSOM) for excitation and detection. The measurements with a spatial resolution of 100 nm are implemented by scanning the fiber tip along the unprepared front facets of standard devices. PL is collected by the fiber tip, whereas PCs are extracted from the contacts that are anyway present for power supply. The mechanisms of signal generation are addressed in detail. The components of the `optical active region', multiple quantum wells (MQW), WGs, and cladding layers are separately inspected. Even separate analysis of p- and n-sections of the WG become possible. Defect levels are detected in the p-part of the WG. Their presence is consistent with the doping by Mg. An increased efficiency of carrier capture into InGaN/GaN WGs compared to GaN WGs is observed. Thus, beyond the improved optical confinement, the electrical confinement is improved, as well. NSOM PL and PC at GaN based devices do not reach the clarity and spatial resolution for WG mode analysis as seen before for GaAs based devices. This is due to higher modal absorption and higher WG losses. NSOM based optical analysis turns out to be an efficient tool for analysis of single layers grown into InAlGaN/GaN diode laser structures, even if this analysis is done at a packaged ready-to-work device.

  4. Laser induced damage threshold on metallic surfaces during laser cleaning

    CSIR Research Space (South Africa)

    Labuschagne, K

    2005-07-01

    Full Text Available laser paint removal. Laser induced damage on 316L stainless steel was studied, with the target subjected to single and multiple pulse irradiations using a Q-switched Nd:YAG, with fluences between 0.15 and 11.8 J/cm2. Several different damage morphologies...

  5. Unstable propagation of a Gaussian laser beam in a plasma waveguide

    International Nuclear Information System (INIS)

    Feit, M.D.; Maiden, D.E.

    1976-01-01

    Laser heating of long magnetically confined plasma columns to fusion temperatures requires propagation of a trapped laser beam over considerable distances. The present paper employs the parabolic approximation to the wave equation to analyze the propagation of a Gaussian beam through a plasma with a parabolic transverse density profile. Although propagation is stable in the axially uniform case, exhibiting alternate focusing and defocusing of the beam, it is unstable to small axial perturbations of certain wavelengths. In particular, an exponentially growing beam radius results from perturbations at wavelengths near that associated with the alternate focusing and defocusing mentioned above

  6. Fiber‐free coupling between bulk laser beams and on‐chip polymer‐based multimode waveguides

    DEFF Research Database (Denmark)

    Jensen, Thomas Glasdam; Nielsen, Lars Bue; Kutter, Jörg Peter

    2011-01-01

    light from a bulk beam to on‐chip waveguides and back into a bulk beam again. Using this setup, as much as 20% of the light coming from the source can be retrieved after passing through the on‐chip waveguides. The proposed setup is based on a pin‐aided alignment system that makes it possible to change...

  7. The Theory for the Dielectric Slab Waveguide with Complex Refractive Index Applied to GaAs Lasers

    DEFF Research Database (Denmark)

    Buus, Jens

    1977-01-01

    In this paper we investigate the homogeneous dielectric slab waveguide in the case of complex dielectric constants. A method for calculating the field distribution in a dielectric waveguide with an arbitrary symmetrical variation in the refractive index is developed, and some of the results are p...

  8. Progress in metal-insulator-metal waveguide lasers at near-infrared wavelengths

    NARCIS (Netherlands)

    Marell, M.J.H.; Hill, M.T.

    2009-01-01

    Strong light con¯nement can be achieved in metallic cavities which can con¯ne light to volumes with dimensions considerably smaller than the wavelength of light. It was commonly believed, however, that the high losses in metals are prohibitive for laser peration in metallic nano-cavities. Recently

  9. The effect of asymmetric barrier layers in the waveguide region on power characteristics of QW lasers

    DEFF Research Database (Denmark)

    Zubov, F. I.; Zhukov, A. E.; Shernyakov, Yu M.

    2015-01-01

    Current-voltage and light-current characteristics of quantum-well lasers have been studied at high drive currents. The introduction of asymmetric barrier layers adjacent to the active region caused a significant suppression of the nonlinearity in the light-current characteristic and an increase...

  10. A DC excited waveguide multibeam CO2 laser using high frequency ...

    Indian Academy of Sciences (India)

    High power industrial multibeam CO2 lasers consist of a large number of closely packed ... by producing pre-ionization using an auxiliary high frequency pulsed ... of few kilowatts output power, multibeam technique is used [2]. .... gas mixture of CO2, N2 and He enters in each discharge tube individually from .... Commercial.

  11. Q-switched YAG laser vs. punch biopsy excision for iatrogenic radiation tattoo markers--a randomized controlled trial

    DEFF Research Database (Denmark)

    Bregnhøj, A; Haedersdal, M

    2010-01-01

    Ink markers are tattooed as landmarks before radiotherapy of breast cancer with the purpose of obtaining a precise radiation field. The black tattoo spots may cause potential psychological distress for the affected women.......Ink markers are tattooed as landmarks before radiotherapy of breast cancer with the purpose of obtaining a precise radiation field. The black tattoo spots may cause potential psychological distress for the affected women....

  12. Diode-Pumped, 2-Micron, Q-Switched Thulium: Y3Al5O12 (Tm:Yag) Microchip Laser

    Science.gov (United States)

    2011-05-01

    Estimating Beam Quality The beam parameter product ( BPP ), which is defined as the product of a beam’s divergence half-angle and its radius at the waist...is a figure of merit describing how well the beam can be focused to a small spot. The BPP of an ideal Gaussian beam is given by λ/π, where λ is the...beam’s wavelength. A second quantity, M2, also called the Gaussian beam parameter, is defined as the ratio of a measured BPP to an ideal BPP at

  13. A Mid-IR Optical Parametric Oscillator Pumped by an Actively Q-Switched Ho:YAG Ceramic Laser

    Science.gov (United States)

    Yuan, Jin-He; Duan, Xiao-Ming; Yao, Bao-Quan; Li, Jiang; Shen, Ying-Jie; Cui, Zheng; Dai, Tong-Yu; Pan, Yu-Bai

    2015-08-01

    Not Available Supported by the National Natural Science Foundation of China under Grant Nos 61308009, 61405047 and 50990301, the Fundamental Research Funds for the Central Universities under Grant Nos HIT.NSRIF.2014044 and HIT.NSRIF.2015042, and the Science Fund for Outstanding Youths of Heilongjiang Province under Grant No JQ201310.

  14. XPS and SIMS study of aluminium native oxide modifications induced by Q-switched Nd :YAG laser treatment

    CSIR Research Space (South Africa)

    Barnier, V

    2006-04-01

    Full Text Available with fluences between 0.7 and 1.7 J/cm2, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) revealed thermal oxidation with an increase of the oxide-layer thickness for 0.7–1.3 J/cm2. Above a threshold at about 1.3 J/cm2 the oxide...

  15. Nd:YAG Lasers Treating of Carious Lesion and Root Canal In Vitro

    Directory of Open Access Journals (Sweden)

    Danqing Xia

    2012-01-01

    Full Text Available Dental caries is a transmissible bacterial disease process, with cavities at the end, and caused by acids from bacterial metabolism. The essence of dental treatment is to clean and disinfect bacterial contamination from the tooth. In this work, we tried to demonstrate the cleaning and disinfecting effects of Nd:YAG laser irradiation on dental carious lesion and root canal in vitro. Acousto-optic Q-switched quasicontinuous and Cr3+:YAG crystal Q-switched pulse Nd:YAG lasers were employed to treat caries lesion and the root canal, respectively. Results showed that acousto-optic Q-switched quasicontinuous Nd:YAG laser irradiation and Cr3+:YAG crystal Q-switched pulse Nd:YAG laser irradiation could rapidly clean decayed material and bacterial contamination from dental carious lesion and the narrow tail end of root canal with minimally invasive in vitro, respectively. It was concluded that acousto-optic Q-switched quasicontinuous laser irradiation may be a rapid and effective alternative caries treatment, and Cr3+:YAG crystal Q-switched pulse Nd:YAG laser irradiation may be an effective method for canal cleaning and disinfecting during root canal therapy.

  16. High-power Yb- and Tm-doped double tungstate channel waveguide lasers

    NARCIS (Netherlands)

    van Dalfsen, Koop; Geskus, D.; Ay, F.; Worhoff, Kerstin; Aravazhi, S.; Pollnau, Markus

    The potassium double tungstates KGd(WO4)2, KY(WO4)2, and KLu(WO4)2 are excellent candidates for solid-state lasers because of their high refractive index of ~2.0-2.1, the large transition cross-sections of rare-earth (RE3+) ions doped into these hosts, and a reasonably large thermal conductivity of

  17. Ultrafast direct laser writing of cladding waveguides in the 0.8CaSiO{sub 3}-0.2Ca{sub 3}(PO{sub 4}){sub 2} eutectic glass doped with Nd{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Martínez de Mendívil, J., E-mail: jon.martinez@uam.es; Lifante, G. [Departamento de Física de Materiales, C-04, Facultad de Ciencias, Universidad Autónoma de Madrid, 28.049 Madrid (Spain); Sola, D.; Peña, J. I. [Departamento de Ciencia y Tecnología de Materiales y Fluidos, Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-CSIC, 50.018 Zaragoza (Spain); Vázquez de Aldana, J. R. [Grupo de Investigación en Microprocesado de Materiales con Láser, Departamento de Física Aplicada, Universidad de Salamanca, 37.008 Salamanca (Spain); Aza, A. H. de; Pena, P. [Instituto de Cerámica y Vidrio-CSIC, 28.049 Madrid (Spain)

    2015-01-28

    We report on tubular cladding optical waveguides fabricated in Neodymium doped Wollastonite-Tricalcium Phosphate glass in the eutectic composition. The glass samples were prepared by melting the eutectic powder mixture in a Pt-Rh crucible at 1600 °C and pouring it in a preheated brass mould. Afterwards, the glass was annealed to relieve the inner stresses. Cladding waveguides were fabricated by focusing beneath the sample surface using a pulsed Ti:sapphire laser with a pulsewidth of 120 fs working at 1 kHz. The optical properties of these waveguides have been assessed in terms of near-field intensity distribution and transmitted power, and these results have been compared to previously reported waveguides with double-line configuration. Optical properties have also been studied as function of the temperature. Heat treatments up to 700 °C were carried out to diminish colour centre losses where waveguide's modes and transmitted power were compared in order to establish the annealing temperature at which the optimal optical properties were reached. Laser experiments are in progress to evaluate the ability of the waveguides for 1064 nm laser light generation under 800 nm optical pumping.

  18. Status of 2 micron laser technology program

    Science.gov (United States)

    Storm, Mark

    1991-01-01

    The status of 2 micron lasers for windshear detection is described in viewgraph form Theoretical atmospheric and instrument system studies have demonstrated that the 2.1 micron Ho:YAG lasers can effectively measure wind speeds in both wet and dry conditions with accuracies of 1 m/sec. Two micron laser technology looks very promising in the near future, but several technical questions remain. The Ho:YAG laser would be small, compact, and efficient, requiring little or no maintenance. Since the Ho:YAG laser is laser diode pumped and has no moving part, the lifetime of this laser would be directly related to the diode laser lifetimes which can perform in excess of 10,000 hours. Efficiencies of 3 to 12 percent are expected, but laser demonstrations confirming the ability to Q-switch this laser are required. Coherent laser operation has been demonstrated for both the CW and Q-switched lasers.

  19. BeZnCdSe quantum-well ridge-waveguide laser diodes under low threshold room-temperature continuous-wave operation

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Jijun [Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China); Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Akimoto, Ryoichi, E-mail: r-akimoto@aist.go.jp [Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan)

    2015-10-19

    Low threshold current ridge-waveguide BeZnCdSe quantum-well laser diodes (LDs) have been developed by completely etching away the top p-type BeMgZnSe/ZnSe:N short-period superlattice cladding layer, which can suppress the leakage current that flows laterally outside of the electrode. The waveguide LDs are covered with a thick SiO{sub 2} layer and planarized with chemical-mechanical polishing and a reactive ion etching process. Room-temperature lasing under continuous-wave condition is achieved with the laser cavity formed by the cleaved waveguide facets coated with high-reflectivity dielectric films. For a 4 μm-wide green LD lasing around a wavelength of 535 nm, threshold current and voltage of 7.07 mA and 7.89 V are achieved for a cavity length of 300 μm, and the internal differential quantum efficiency, internal absorption loss, gain constant, and nominal transparency current density are estimated to be 27%, 4.09 cm{sup −1}, 29.92 (cm × μm)/kA and 6.35 kA/(cm{sup 2 }× μm), respectively. This compact device can realize a significantly improved performance with much lower threshold power consumption, which would benefit the potential application for ZnSe-based green LDs as light sources in full-color display and projector devices installed in consumer products such as pocket projectors.

  20. Laser induced breakdown spectroscopy in water | Boudjemai ...

    African Journals Online (AJOL)

    Sparks were generated in water by the focused beam of a Q-switched Nd:YAG laser Na and Cu aqueous solutions exhibited fluorescence signal on the decaying edge of plasma emission at their respective characteristic resonance lines. Potential of the laser plasma spectroscopy for in-situ pollution monitoring in natural ...

  1. Laser tattoo removal with preceding ablative fractional treatment

    Science.gov (United States)

    Cencič, Boris; Možina, Janez; Jezeršek, Matija

    2013-06-01

    A combined laser tattoo removal treatment, first the ablative fractional resurfacing (AFR) with an Er:YAG laser and then the q-switched (QSW) Nd:YAG laser treatment, was studied. Experiments show that significantly higher fluences can be used for the same tissue damage levels.

  2. Narrow ridge waveguide high power single mode 1.3-μm InAs/InGaAs ten-layer quantum dot lasers

    Directory of Open Access Journals (Sweden)

    Cao Q

    2007-01-01

    Full Text Available AbstractTen-layer InAs/In0.15Ga0.85As quantum dot (QD laser structures have been grown using molecular beam epitaxy (MBE on GaAs (001 substrate. Using the pulsed anodic oxidation technique, narrow (2 μm ridge waveguide (RWG InAs QD lasers have been fabricated. Under continuous wave operation, the InAs QD laser (2 × 2,000 μm2 delivered total output power of up to 272.6 mW at 10 °C at 1.3 μm. Under pulsed operation, where the device heating is greatly minimized, the InAs QD laser (2 × 2,000 μm2 delivered extremely high output power (both facets of up to 1.22 W at 20 °C, at high external differential quantum efficiency of 96%. Far field pattern measurement of the 2-μm RWG InAs QD lasers showed single lateral mode operation.

  3. Mid-infrared source with 0.2 J pulse energy based on nonlinear conversion of Q-switched pulses in ZnGeP2.

    Science.gov (United States)

    Haakestad, Magnus W; Fonnum, Helge; Lippert, Espen

    2014-04-07

    Mid-infrared (3-5 μm) pulses with high energy are produced using nonlinear conversion in a ZnGeP(2)-based master oscillator-power amplifier, pumped by a Q-switched cryogenic Ho:YLF oscillator. The master oscillator is based on an optical parametric oscillator with a V-shaped 3-mirror ring resonator, and the power amplifier is based on optical parametric amplification in large-aperture ZnGeP(2) crystals. Pulses with up to 212 mJ energy at 1 Hz repetition rate are obtained, with FWHM duration 15 ns and beam quality M(2) = 3.

  4. A widespread allergic reaction to black tattoo ink caused by laser treatment.

    Science.gov (United States)

    Bernstein, Eric F

    2015-02-01

    This is the first reported case of a local and widespread reaction in a 39 year old woman, to black tattoo ink, induced by Q-switched laser treatment. A 39 year old woman was treated with the Q-switched Nd:YAG laser for removal of a decorative tattoo of her lower back. Subsequent to laser treatment, a severe, widespread allergic reaction developed within and surrounding the treated tattoo. Tattoo reactions subsequent to laser treatment should be considered in addition to reactions to topical antibiotics or wound dressings, following laser treatment of tattoos. © 2015 Wiley Periodicals, Inc.

  5. Reflectivity of transient Bragg reflection gratings in fiber laser with laser-wavelength selfsweeping

    Czech Academy of Sciences Publication Activity Database

    Peterka, Pavel; Honzátko, Pavel; Koška, Pavel; Todorov, Filip; Aubrecht, Jan; Podrazký, Ondřej; Kašík, Ivan

    2014-01-01

    Roč. 22, č. 24 (2014), s. 30024-30031 ISSN 1094-4087 R&D Projects: GA ČR(CZ) GAP205/11/1840 Institutional support: RVO:67985882 Keywords : Ytterbium-doped fiber * Laser optics * Q switched lasers Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.488, year: 2014

  6. Development of frequency tunable Ti:sapphire laser and dye laser pumped by a pulsed Nd:YAG laser

    International Nuclear Information System (INIS)

    Yi, Jong Hoon; Horn, Roland; Wendt, K.

    2001-01-01

    We investigated lasing characteristics of two kinds of tunable laser, liquid dye laser and solid Ti:sapphire crystal laser, pumped by high pulse repetition rate Nd:YAG laser. Dye laser showed drastically reduced pulsewidth compared with that of pump laser and it also contained large amount of amplified spontaneous emission. Ti:sapphire laser showed also reduced pulsewidth. But, the laser conversion pump laser and Ti:sapphire laser pulse, we used a Brewster-cut Pockel's cell for Q-switching. The laser was frequency doubled by a type I BBO crystal outside of the cavity.

  7. Wave-guided optical waveguides

    DEFF Research Database (Denmark)

    Palima, Darwin; Bañas, Andrew Rafael; Vizsnyiczai, George

    2012-01-01

    This work primarily aims to fabricate and use two photon polymerization (2PP) microstructures capable of being optically manipulated into any arbitrary orientation. We have integrated optical waveguides into the structures and therefore have freestanding waveguides, which can be positioned anywhe...... bridge the diffraction barrier. This structure-mediated paradigm may be carried forward to open new possibilities for exploiting beams from far-field optics down to the subwavelength domain....

  8. Intense Plasma Waveguide Terahertz Sources for High-Field THz Probe Science with Ultrafast Lasers for Solid State Physics

    Science.gov (United States)

    2016-08-25

    Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a...Summary 2 1. Introduction 2. Two colour excitation of intense terahertz radiation in MOFs 2 3. Terahertz optical nonlinearities in...of 2- colour THz generation and propagation in waveguides that we have developed to evaluate fibre designs before fabrication is only one

  9. Highly efficient channel waveguide lasers at 1 µm and 2 µm in refractive-index-engineered potassium double tungstates

    NARCIS (Netherlands)

    van Dalfsen, Koop; Geskus, D.; García Blanco, Sonia Maria; Pollnau, Markus

    Epitaxial growth of rare-earth-ion-activated KY(1-x-y)Gd(x)Lu(y)(WO4)2 co-doped thin layers onto KY(WO4)2 substrates has enabled lattice-matched waveguides with high refractive-index contract and large variation of the active rare-earth-ion concentration. In Yb3+-activated micro-structured channel

  10. Progress on erbium-doped waveguide components

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Berendt, Martin Ole; Broeng, Jes

    1997-01-01

    The recent development in erbium-doped fiber amplifiers, and fiber lasers is reviewed. Also the latest results on planar erbium-doped waveguide amplifiers and high erbium concentration characterisation methods are presented...

  11. Increased epidermal laser fluence through simultaneous ultrasonic microporation

    Science.gov (United States)

    Whiteside, Paul J. D.; Chininis, Jeff A.; Schellenberg, Mason W.; Qian, Chenxi; Hunt, Heather K.

    2016-03-01

    Lasers have demonstrated widespread applicability in clinical dermatology as minimally invasive instruments that achieve photogenerated responses within tissue. However, before reaching its target, the incident light must first transmit through the surface layer of tissue, which is interspersed with chromophores (e.g. melanin) that preferentially absorb the light and may also generate negative tissue responses. These optical absorbers decrease the efficacy of the procedures. In order to ensure that the target receives a clinically relevant dose, most procedures simply increase the incident energy; however, this tends to exacerbate the negative complications of melanin absorption. Here, we present an alternative solution aimed at increasing epidermal energy uence while mitigating excess absorption by unintended targets. Our technique involves the combination of a waveguide-based contact transmission modality with simultaneous high-frequency ultrasonic pulsation, which alters the optical properties of the tissue through the agglomeration of dissolved gasses into micro-bubbles within the tissue. Doing so effectively creates optically transparent pathways for the light to transmit unobstructed through the tissue, resulting in an increase in forward scattering and a decrease in absorption. To demonstrate this, Q-switched nanosecond-pulsed laser light at 532nm was delivered into pig skin samples using custom glass waveguides clad in titanium and silver. Light transmission through the tissue was measured with a photodiode and integrating sphere for tissue with and without continuous ultrasonic pulsation at 510 kHz. The combination of these techniques has the potential to improve the efficiency of laser procedures while mitigating negative tissue effects caused by undesirable absorption.

  12. Refresher Course on Lasers and Applications in Chemical Processes

    Indian Academy of Sciences (India)

    lasers, modes of laser, mode locking, Q-switching, nonlinear optical materials, electro- optic and magneto-optic materials. It will also include laboratory demonstration experi- ments in selected areas of fluorescence and pump-probe methods. Teachers who wish to participate in the Refresher Course should submit their brief.

  13. Laser Surgeon, Client Education, and Satisfaction with Tattoo Removal

    DEFF Research Database (Denmark)

    Hutton Carlsen, Katrina; Esmann, Jørgen; Serup, Jørgen

    2017-01-01

    Studies of satisfaction with tattoo removal outcomes by laser, rated by clients themselves, including qualitative aspects, are sparse. We studied long-term results and client satisfaction with tattoo removal by Q-switched YAG laser. Client satisfaction is influenced by numerous factors: pretreatm...

  14. Reflectivity of transient Bragg reflection gratings in fiber laser with laser-wavelength self-sweeping: erratum

    Czech Academy of Sciences Publication Activity Database

    Peterka, Pavel; Honzátko, Pavel; Koška, Pavel; Todorov, Filip; Aubrecht, Jan; Podrazký, Ondřej; Kašík, Ivan

    2016-01-01

    Roč. 24, č. 14 (2016), s. 16222-16223 ISSN 1094-4087 R&D Projects: GA ČR(CZ) GA16-13306S Institutional support: RVO:67985882 Keywords : Ytterbium-doped fiber * Laser optics * Q switched lasers Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.307, year: 2016

  15. Ultra-high speed all-optical signal processing using silicon waveguides and a carbon nanotubes based mode-locked laser

    DEFF Research Database (Denmark)

    Ji, Hua

    This thesis concerns the use of nano-engineered silicon waveguides for ultra-high speed optical serial data signal processing. The fundamental nonlinear properties of nano-engineered silicon waveguides are characterized. Utilizing the nonlinear effect in nano-engineered silicon waveguides for dem...

  16. Broadband generation by multiple four-wave mixing process due to ASE Q-switching in high-power double-clad ytterbium-doped fiber amplifier

    Science.gov (United States)

    Chowdhury, Sourav D.; Shekhar, Nishant; Saha, Maitreyee; Sen, Ranjan; Pal, Mrinmay

    2014-11-01

    Broadband output from 1060nm to 1700nm and cascaded four-wave mixing generated red light pulsing is observed in a fiber amplifier set up consisting of a 5.5m double clad, double D shaped Ytterbium doped fiber, a single clad passive fiber for excess pump absorption and a splitter, both with and without a CW seed. Self-pulsing occurs from ASE due to passive Q-switching by saturable absorption effect of the active fiber and also depends on splice loss. The pulses generate broadband output by multiple four-wave mixing process with maximum broadening efficiency near 1300nm which is the zero dispersion wavelength for silica fiber. Pulses traveling both in forward and backward direction have enough peak power and energy to damage splice points and fiber components. When seeded the self-pulsing and broadband generation is often suppressed but again generate at increased pump powers.

  17. An apparatus comprising a waveguide-modulator and laser-diode and a method of manufacture thereof

    KAUST Repository

    Ooi, Boon S.; Shen, Chao; Ng, Tien Khee; Alyamani, Ahmed Y.; Eldesouki, Munir M.

    2017-01-01

    Example apparatuses are provided for simultaneous generation of high intensity light and modulated light signals at low modulation bias operating characteristics. An example apparatus includes a semipolar or nonpolar GaN-based substrate, a reverse- biased waveguide modulator section, and a forward-biased gain section based on InGaN/GaN quantum-well active regions, wherein the forward-biased gain section is grown on the semipolar or nonpolar GaN-based substrate. Methods of manufacturing the apparatuses described herein are also contemplated and described herein.

  18. An apparatus comprising a waveguide-modulator and laser-diode and a method of manufacture thereof

    KAUST Repository

    Ooi, Boon S.

    2017-04-13

    Example apparatuses are provided for simultaneous generation of high intensity light and modulated light signals at low modulation bias operating characteristics. An example apparatus includes a semipolar or nonpolar GaN-based substrate, a reverse- biased waveguide modulator section, and a forward-biased gain section based on InGaN/GaN quantum-well active regions, wherein the forward-biased gain section is grown on the semipolar or nonpolar GaN-based substrate. Methods of manufacturing the apparatuses described herein are also contemplated and described herein.

  19. Optical and structural properties of Pr:GGGcrystalline thin film waveguides grown by pulsed-laser deposition

    Czech Academy of Sciences Publication Activity Database

    Lančok, Ján; Garapon, C.; Jelínek, Miroslav; Mugnier, J.; Brenier, R.

    2005-01-01

    Roč. 81, - (2005), s. 1477-1483 ISSN 0947-8396 R&D Projects: GA ČR(CZ) GP106/01/D017 Grant - others:European Community- Marie Curie Fellowhip(XE) HP MF-CT-2001-01492; CLYME(FR) GEMPPM-UMR5510 CNRS-INSA Institutional research plan: CEZ:AV0Z10100522 Keywords : Pr: GGG * thin films * waveguide Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.990, year: 2005

  20. Fabrication of ultrafast laser written low-loss waveguides in flexible As₂S₃ chalcogenide glass tape.

    Science.gov (United States)

    Lapointe, Jerome; Ledemi, Yannick; Loranger, Sébastien; Iezzi, Victor Lambin; Soares de Lima Filho, Elton; Parent, Francois; Morency, Steeve; Messaddeq, Younes; Kashyap, Raman

    2016-01-15

    As2S3 glass has a unique combination of optical properties, such as wide transparency in the infrared region and a high nonlinear coefficient. Recently, intense research has been conducted to improve photonic devices using thin materials. In this Letter, highly uniform rectangular single-index and 2 dB/m loss step-index optical tapes have been drawn by the crucible technique. Low-loss (writing process in thin glass is also presented to facilitate a repeatable waveguide inscription recipe.

  1. Macroparticle acceleration by laser induced ablation pressure

    International Nuclear Information System (INIS)

    Burgess, M.D.J.; Motz, H.; Rumsby, P.T.

    1976-01-01

    In this paper it is shown that the theoretical scaling of plasma pressure is very closely obeyed using ordinary Q-switched laser pulses, resulting in velocities of over 2 x 10 4 cm s -1 . The problems associated with increasing this velocity whilst still not rupturing the pellet have also been examined and an experiment to determine the results described. (orig.) [de

  2. Evaluation of laser cleaning for the restoration of tarnished silver artifacts

    Energy Technology Data Exchange (ETDEWEB)

    Palomar, T., E-mail: t.palomar@csic.es [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Depto. de Conservação e Restauro and Research Unit VICARTE-Vidro e Cerâmica para as Artes, Campus de Caparica, FCT-UNL, Quinta da Torre, 2829-516 Caparica (Portugal); Oujja, M. [Instituto de Química Física Rocasolano (IQFR-CSIC), Serrano 119, 28006 Madrid (Spain); Llorente, I.; Ramírez Barat, B. [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Cañamares, M.V. [Instituto de Estructura de la Materia (IEM-CSIC), Serrano 121, 28006 Madrid (Spain); Cano, E. [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Castillejo, M. [Instituto de Química Física Rocasolano (IQFR-CSIC), Serrano 119, 28006 Madrid (Spain)

    2016-11-30

    Highlights: • Cyclic application of Q-switched Nd:YAG laser cleaning induces irreversible changes on pure silver. • Laser cleaning using Q-switched Nd:YAG laser at 1064 nm induces loss of material and color changes. • Laser cleaning using Q-switched Nd:YAG laser at 532 nm seems the most appropriate for cleaning sterling silver objects. - Abstract: In this study we evaluate the laser cleaning of tarnished pure and sterling silver substrates using a nanosecond Q-switched Nd:YAG laser at 1064, 532 and 266 nm. To assess the effects associated with cyclic laser cleaning treatments, several cycles of tarnishing followed by laser cleaning were applied on silver coupons that were characterized by gravimetry, colorimetry, scanning electron microscopy, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. According to the obtained results, none of the three wavelengths is recommended for laser cleaning of pure silver objects, while for sterling silver artifacts, the visible laser wavelength of 532 nm seems the most appropriate.

  3. COMPACT ATHERMAL OPTICAL WAVEGUIDE USING THERMAL EXPANSION AMPLIFICATION

    DEFF Research Database (Denmark)

    2001-01-01

    A method of temperature stabilising optical waveguides having positive thermal optical path length expansion, in particular fiber Bragg gratings or optical fiber DFB lasers or optical fiber DBR lasers, comprising affixing the optical waveguide to at least two points of a negative expanding fixture...

  4. Focused-ion-beam nano-structured rib channel waveguides in KY(WO4)2 for laser applications

    NARCIS (Netherlands)

    Gardillou, F.; Romanyuk, Y.E.; Pavius, M.; Borca, C.N.; Salathé, R.P.; Pollnau, Markus

    2006-01-01

    Bulk $KY(WO_4)_2$ (hereafter KYW) laser crystals doped with rare-earth ions are recognized to be among the most promising host materials for obtaining novel solid-state lasers. The rare-earth ions $RE^{3+}$ are easily incorporated in the KYW structure by replacing the $Y{3+}$ ions, resulting in a

  5. Newer Trends in Laser Tattoo Removal

    Science.gov (United States)

    Shah, Swapnil D; Aurangabadkar, Sanjeev J

    2015-01-01

    Q switched lasers are the current gold standard for laser tattoo removal. Though these systems are generally quite effective in clearing tattoos & have an established safety record, certain limitations exist while following the standard protocol. To overcome these limitation newer techniques such as multipass method, combination treatments with chemical agent and other laser have been introduced. These methods help in faster, less painful and complication free tattoo removal. PMID:25949019

  6. Newer trends in laser tattoo removal

    Directory of Open Access Journals (Sweden)

    Swapnil D Shah

    2015-01-01

    Full Text Available Q switched lasers are the current gold standard for laser tattoo removal. Though these systems are generally quite effective in clearing tattoos & have an established safety record, certain limitations exist while following the standard protocol. To overcome these limitation newer techniques such as multipass method, combination treatments with chemical agent and other laser have been introduced. These methods help in faster, less painful and complication free tattoo removal.

  7. All optical wavelength conversion and parametric amplification in Ti:PPLN channel waveguides for telecommunication applications

    Energy Technology Data Exchange (ETDEWEB)

    Nouroozi, Rahman

    2010-10-19

    conversion is based on a polarization maintaining fiber loop configuration. Since both polarization components can be converted in a contra-directional single-pass waveguide, differential group delay (DGD) equalization between them is automatically provided. With such polarization diversity scheme an error-free polarization insensitive conversion of 320 Gb/s differential quaternary phase shift keying (DQPSK) data with signal pulses of 1.4 ps width has been achieved using the packaged and pigtailed cSHG/DFG-based wavelength converter. No significant broadening or distortion of the converted data pulses was observed. This approach results in a tuneable output wavelength of the idler whereas the input signal wavelength can be kept fixed. In a 70 mm long Ti:PPLN channel guide a conversion efficiency of {proportional_to}-7.5 dB has been achieved by 80 mW (20 mW) of coupled pump (control) power level with less than {+-}0.5 dB of residual polarization dependence. The tuning range of the idler covers the whole Cband. However, in contrast to cSHG/DFG, pulse broadening of the converted signal will limit the data rate for cSFG/DFG. For sufficiently high pump power levels wavelength conversion by DFG is accompanied by significant optical parametric amplification (OPA) of the input signal. To increase the fundamental power handling flexibility and to avoid photorefractive effect, a low duty cycle Q-switched diode-pumped-solid-state (DPSS) laser has been used as the fundamental source. With 2.5 W of fundamental peak power {proportional_to}22 dB of signal gain has been measured. (orig.)

  8. Nonlinear optical localization in embedded chalcogenide waveguide arrays

    International Nuclear Information System (INIS)

    Li, Mingshan; Huang, Sheng; Wang, Qingqing; Chen, Kevin P.; Petek, Hrvoje

    2014-01-01

    We report the nonlinear optical localization in an embedded waveguide array fabricated in chalcogenide glass. The array, which consists of seven waveguides with circularly symmetric cross sections, is realized by ultrafast laser writing. Light propagation in the chalcogenide waveguide array is studied with near infrared laser pulses centered at 1040 nm. The peak intensity required for nonlinear localization for the 1-cm long waveguide array was 35.1 GW/cm 2 , using 10-nJ pulses with 300-fs pulse width, which is 70 times lower than that reported in fused silica waveguide arrays and with over 7 times shorter interaction distance. Results reported in this paper demonstrated that ultrafast laser writing is a viable tool to produce 3D all-optical switching waveguide circuits in chalcogenide glass

  9. The use of laser beams for plasma diagnostics

    International Nuclear Information System (INIS)

    Gex, J.P.; Jolas, A.; Launspach, J.; Schirmann, D.

    1975-01-01

    The optical properties of lasers allow them to be a promising source for plasma diagnosis. The Q-switched lasers provide the opportunity to make observations in a very short time interval down to a few picoseconds. The laser space and time coherence properties allow interferometric measurements of plasma electron densities. Thus in the experiments of laser-matter interactions, the radiation obtained by frequency conversion of the Nd: glass laser emission is used for density measurements (up to 10 20 cm -3 ) in small scale plasmas (approximately equal to 1mm). Owing to the monochromaticity and high intensity of the Q-switched laser radiation, density fluctuations and microscopic instabilities of the plasma can be studied by Thompson scattering measurements. Finally, some statistically isotropic media become birefringent under the action of the strong electrical field of the laser beam radiation. This effect can be used for laser pulse duration measurements in a range not exceeding a few picoseconds [fr

  10. Measurement of carrier lifetime and linewidth enhancement factor for 1.5- mu m ridge-waveguide laser amplifier

    DEFF Research Database (Denmark)

    Storkfelt, Niels; Mikkelsen, B.; Olesen, D. S.

    1991-01-01

    Semiconductor optical amplifiers are used for investigation of the effective carrier lifetime and the linewidth enhancement factor. Contrary to semiconductor lasers, semiconductor optical amplifiers allow measurement at high levels of injected carrier density. The carrier lifetime and the linewid...

  11. Enhanced high harmonic generation driven by high-intensity laser in argon gas-filled hollow core waveguide

    International Nuclear Information System (INIS)

    Cassou, Kevin; Daboussi, Sameh; Hort, Ondrej; Descamps, Dominique; Petit, Stephane; Mevel, Eric; Constant, Eric; Guilbaud, Oilvier; Kazamias, Sophie

    2014-01-01

    We show that a significant enhancement of the photon flux produced by high harmonic generation can be obtained through guided configuration at high laser intensity largely above the saturation intensity. We identify two regimes. At low pressure, we observe an intense second plateau in the high harmonic spectrum in argon. At relatively high pressure, complex interplay between strongly time-dependent ionization processes and propagation effects leads to important spectral broadening without loss of spectral brightness. We show that the relevant parameter for this physical process is the product of laser peak power by gas pressure. We compare source performances with high harmonic generation using a gas jet in loose focusing geometry and conclude that the source developed is a good candidate for injection devices such as seeded soft x-ray lasers or free electron lasers in the soft x-ray range. (authors)

  12. Stable narrow spacing dual-wavelength Q-switched graphene oxide embedded in a photonic crystal fiber

    International Nuclear Information System (INIS)

    Ahmad, H; Soltanian, M R K; Alimadad, M; Harun, S W

    2014-01-01

    An ultra-stable dual-wavelength saturable absorber based on a cladding-embedded commercial graphene oxide (GO) solution by capillary action in a solid core photonic crystal fiber (PCF) is demonstrated for the first time. The saturation absorption property is achieved through evanescent coupling between the guided light and the cladding-filled graphene layers. Stable spacing dual-wavelength fiber lasing is attained by controlling the polarization state of a simple 0.9 m long ring of highly doped Leikki Er80-8/125 erbium-doped fiber as the primary gain medium with PCF, polarization controller and tunable bandpass filter. Embedded GO is used to generate the desired pulsed output, and the laser is capable of generating pulses having a repetition rate of 24 kHz with an average output power and pulse energy of 0.167 mW and 8.98 nJ, respectively, at the maximum pump power of 220 mW. (paper)

  13. Ruby laser for treatment of tattoos: technical considerations affecting clinical use

    Science.gov (United States)

    Grove, Robert E.

    1990-06-01

    Recent clinical research on the use of ruby lasers for the treatment of tattoos and FIlk approval of a commercial system have renewed interest in this device. In this paper the principles of Q-switched ruby laser operation are reviewed, and potential sources of error in the estimation of delivered fluence are discussed.

  14. Sm 3+-doped polymer optical waveguide amplifiers

    Science.gov (United States)

    Huang, Lihui; Tsang, Kwokchu; Pun, Edwin Yue-Bun; Xu, Shiqing

    2010-04-01

    Trivalent samarium ion (Sm 3+) doped SU8 polymer materials were synthesized and characterized. Intense red emission at 645 nm was observed under UV laser light excitation. Spectroscopic investigations show that the doped materials are suitable for realizing planar optical waveguide amplifiers. About 100 μm wide multimode Sm 3+-doped SU8 channel waveguides were fabricated using a simple UV exposure process. At 250 mW, 351 nm UV pump power, a signal enhancement of ˜7.4 dB at 645 nm was obtained for a 15 mm long channel waveguide.

  15. Hollow cylindrical plasma filament waveguide with discontinuous finite thickness cladding

    International Nuclear Information System (INIS)

    Alshershby, Mostafa; Hao Zuoqiang; Lin Jingquan

    2013-01-01

    We have explored here a hollow cylindrical laser plasma multifilament waveguide with discontinuous finite thickness cladding, in which the separation between individual filaments is in the range of several millimeters and the waveguide cladding thickness is in the order of the microwave penetration depth. Such parameters give a closer representation of a realistic laser filament waveguide sustained by a long stable propagation of femtosecond (fs) laser pulses. We report how the waveguide losses depend on structural parameters like normalized plasma filament spacing, filament to filament distance or pitch, normal spatial frequency, and radius of the plasma filament. We found that for typical plasma parameters, the proposed waveguide can support guided modes of microwaves in extremely high frequency even with a cladding consisting of only one ring of plasma filaments. The loss of the microwave radiation is mainly caused by tunneling through the discontinuous finite cladding, i.e., confinement loss, and is weakly dependent on the plasma absorption. In addition, the analysis indicates that the propagation loss is fairly large compared with the loss of a plasma waveguide with a continuous infinite thickness cladding, while they are comparable when using a cladding contains more than one ring. Compared to free space propagation, this waveguide still presents a superior microwave transmission to some distance in the order of the filamentation length; thus, the laser plasma filaments waveguide may be a potential channel for transporting pulsed-modulated microwaves if ensuring a long and stable propagation of fs laser pulses.

  16. Quantum waveguides

    CERN Document Server

    Exner, Pavel

    2015-01-01

    This monograph explains the theory of quantum waveguides, that is, dynamics of quantum particles confined to regions in the form of tubes, layers, networks, etc. The focus is on relations between the confinement geometry on the one hand and the spectral and scattering properties of the corresponding quantum Hamiltonians on the other. Perturbations of such operators, in particular, by external fields are also considered. The volume provides a unique summary of twenty five years of research activity in this area and indicates ways in which the theory can develop further. The book is fairly self-contained. While it requires some broader mathematical physics background, all the basic concepts are properly explained and proofs of most theorems are given in detail, so there is no need for additional sources. Without a parallel in the literature, the monograph by Exner and Kovarik guides the reader through this new and exciting field.

  17. Random laser action in bovine semen

    Science.gov (United States)

    Smuk, Andrei; Lazaro, Edgar; Olson, Leif P.; Lawandy, N. M.

    2011-03-01

    Experiments using bovine semen reveal that the addition of a high-gain water soluble dye results in random laser action when excited by a Q-switched, frequency doubled, Nd:Yag laser. The data shows that the linewidth collapse of the emission is correlated to the sperm count of the individual samples, potentially making this a rapid, low sample volume approach to count determination.

  18. High accuracy 3-D laser radar

    DEFF Research Database (Denmark)

    Busck, Jens; Heiselberg, Henning

    2004-01-01

    We have developed a mono-static staring 3-D laser radar based on gated viewing with range accuracy below 1 m at 10 m and 1 cm at 100. We use a high sensitivity, fast, intensified CCD camera, and a Nd:Yag passively Q-switched 32.4 kHz pulsed green laser at 532 nm. The CCD has 752x582 pixels. Camera...

  19. New configurations for short-pulses high power solid-state lasers: conception and realization of highly doped waveguide amplifiers/lasers grown by liquid phase epitaxy and demonstration of Y2SiO5: Yb and Lu2SiO5: Yb femtosecond lasers

    International Nuclear Information System (INIS)

    Thibault, F.

    2006-04-01

    Yb-doped yttrium and lutetium ortho-silicates, Y 2 SiO 5 :Yb and Lu 2 SiO 5 :Yb respectively, exhibit spectroscopic properties favorable to an efficient laser operation in both high power cw and femtosecond regime. Their first diode-pumped femtosecond operation demonstration lead to exceptional performances in terms of output power and efficiency. In order to realize compact and efficient solid-state laser devices using those materials, we chose a configuration with an Yb-doped medium planar waveguide geometry, grown by liquid phase epitaxy, face-pumped by a single laser diode bar. The growth of highly doped Y 2 SiO 5 :Yb layers, within a large range of compositions and thicknesses, was demonstrated. The refractive index increase due to the substitution of the various dopants is analyzed. The layers spectroscopic properties are similar to the bulk ones, with an noticeably higher crystalline quality. The Yb ion lifetime evolution with respect to its doping shows up a particularly low decrease, proof of a low concentration of extrinsic quenching centers. The covered YSO:24%Yb waveguides exhibit lower than 0.3 dB/cm propagation losses, and provided up to 2.9 dB/cm net amplification at 1082 nm with a single mode output. The realization of the first diode-pumped monolithic cw waveguide lasers was also demonstrated. For a 4% output coupler, they provided up to 340 mW at 1082 nm with a 14% slope efficiency. (author)

  20. Control of ring lasers by means of coupled cavities

    DEFF Research Database (Denmark)

    Buchhave, Preben; Abitan, Haim; Tidemand-Lichtenberg, Peter

    2000-01-01

    Variable phase coupling to an external ring is used to control a unidirectional ring laser. The observed behavior of the coupled rings is explained theoretically. We have found experimentally that by quickly changing the phase of the feedback from the external ring it is possible to Q......-switch the ring laser. Also, at certain values of the phase of the feedback in the external ring, instabilities in the total system occur and oscillations arise in the ring laser....