WorldWideScience

Sample records for doped laser materials

  1. Spectroscopy of Nd-doped laser materials

    Science.gov (United States)

    George, Simi A.; Hayden, Joseph S.

    2014-02-01

    Laser design codes utilize laser properties provided by materials manufacturers for performance modeling. Large scale manufacturing of materials during compositional developments for a particular laser design is not economically feasible. Nevertheless, the laser properties derived from the available sample volumes must be reliable and reproducible. In recent years, as a result of the renewed interest in novel glasses for ultrafast laser applications, SCHOTT has developed improved measurements and methodologies for providing the most accurate information possible to laser scientists. Even though the J-O method is robust and time tested for the spectroscopic characterization of Nd3+, the accuracy of the results requires reliable measurements. This paper outlines the J-O approximation for manifold to manifold transitions, measurements needed, and some of the pitfalls to watch for during the collection of data for Nd-doped materials.

  2. Tetravalent chromium doped laser materials and NIR tunable lasers

    Science.gov (United States)

    Alfano, Robert R. (Inventor); Petricevic, Vladimir (Inventor); Bykov, Alexey (Inventor)

    2008-01-01

    A method is described to improve and produce purer Cr.sup.4+-doped laser materials and lasers with reduced co-incorporation of chromium in any other valence states, such as Cr.sup.3+, Cr.sup.2+, Cr.sup.5+, and Cr.sup.6+. The method includes: 1) certain crystals of olivine structure with large cation (Ca) in octahedral sites such as Cr.sup.4+:Ca.sub.2GeO.sub.4, Cr.sup.4+:Ca.sub.2SiO.sub.4, Cr.sup.4+:Ca.sub.2Ge.sub.xSi.sub.1-xO.sub.4 (where 0NIR laser applications.

  3. Terminal-level relaxation in ND-doped laser materials

    Energy Technology Data Exchange (ETDEWEB)

    Bibeau, C.; Payne, S.A.

    1996-06-01

    During the energy extraction of a 1-{mu}m pulse in a Nd-doped laser material, the Nd-ion population is transferred from the metastable {sup 4}F{sub 3/2} level into the terminal {sup 4}I{sub 11/2} level. The terminal-level lifetime, {tau}{sub 11/2}, is defined in this case as the time it takes the Nd-ion population to decay from the {sup 4}I{sub 11/2} level into the {sup 4}I{sub 9/2} ground state. Several experimental and theoretical approaches over the last three decades have been made to measure the terminal-level lifetime. However, an agreement in the results among the different approaches for a large sampling of laser materials has never been demonstrated. This article presents three independent methods (pump-probe, emission, and energy extraction) for measuring the terminal-level lifetime in Nd:phosphate glass LG-750. The authors find remarkable agreement among the data and determine the {tau}{sub 11/2} lifetime to be 253{+-}50 ps. They extend their studies to show that the results of the pump-probe and emission methods agree to within a factor of two for additional Nd-doped glases and crystals investigated, thus offering validation for the emission method, which is a simpler, indirect approach.

  4. Laser ceramics with rare-earth-doped anisotropic materials.

    Science.gov (United States)

    Akiyama, Jun; Sato, Yoichi; Taira, Takunori

    2010-11-01

    The fabrication of laser-grade anisotropic ceramics by a conventional sintering process is not possible owing to optical scattering at randomly oriented grain boundaries. In this Letter, we report the first (to our knowledge) realization of transparent anisotropic ceramics by using a new crystal orientation process based on large magnetic anisotropy induced by 4f electrons. By slip casting in a 1.4 T magnetic field and subsequent heat treatments, we could successfully fabricate laser-grade calcium fluorapatite ceramics with a loss coefficient of 1.5 cm(-1).

  5. Enhanced Laser Cooling of Rare-Earth-Ion-Doped Composite Material

    Institute of Scientific and Technical Information of China (English)

    JIA You-Hua; ZHONG Biao; JI Xian-Ming; YIN Jian-Ping

    2008-01-01

    We predict enhanced laser cooling performance of rare-earth-ions-doped glasses containing nanometre-sized ultrafine particles, which can be achieved by the enhancement of local field around rare earth ions, owing to the surface plasma resonance of small metallic particles. The influence of energy transfer between ions and the particle is theoretically discussed. Depending on the particle size and the ion emission quantum efficiency, the enhancement of the absorption is predicted. It is concluded that the absorption are greatly enhanced in these composite materials, the cooling power is increased as compared to the bulk material.

  6. Spectroscopic and crystal-field analysis of new Yb-doped laser materials

    Energy Technology Data Exchange (ETDEWEB)

    Haumesser, Paul-Henri; Gaume, Romain; Antic-Fidancev, Elisabeth; Vivien, Daniel; Viana, Bruno [Laboratoire de Chimie Appliquee de l' Etat Solide UMR 75 74, ENSCP, Paris (France)]. E-mail: viana@ext.jussieu.fr

    2001-06-11

    Crystal-field effects are very important as far as laser performances of Yb-doped materials are concerned. In order to simplify the interpretation of low-temperature spectra, two tools derived from a careful examination of crystal-field interaction are presented. Both approaches are successfully applied in the case of new Yb-doped materials, namely Ca{sub 3}Y{sub 2}(BO{sub 3}){sub 4} (CYB), Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4} (CaGB), Sr{sub 3}Y(BO{sub 3}){sub 3} (SrYBO), Ba{sub 3}Lu(BO{sub 3}){sub 3} (BLuB), Y{sub 2}SiO{sub 5} (YSO), Ca{sub 2}Al{sub 2}SiO{sub 7} (CAS) and SrY{sub 4}(SiO{sub 4}){sub 3}O (SYS). The {sup 2}F{sub 7/2} splitting is particularly large in these materials and favourable to a quasi-three-level laser operating scheme. Calculations performed using the point charge electrostatic model for these compounds and using a consistent set of effective atomic charges confirm the experimental results. This should permit to use this model in a predictive approach. (author)

  7. New Mid-IR Lasers Based on Rare-Earth-Doped Sulfide and Chloride Materials

    Energy Technology Data Exchange (ETDEWEB)

    Nostrand, M

    2000-09-01

    Applications in remote-sensing and military countermeasures have driven a need for compact, solid-state mid-IR lasers. Due to multi-phonon quenching, non-traditional hosts are needed to extend current solid-state, room-temperature lasing capabilities beyond {approx} 4 {micro}m. Traditional oxide and fluoride hosts have effective phonon energies in the neighborhood of 1000 cm{sup -1} and 500 cm{sup -1}, respectively. These phonons can effectively quench radiation above 2 and 4 {micro}m, respectively. Materials with lower effective phonon energies such as sulfides and chlorides are the logical candidates for mid-IR (4-10 {micro}m) operation. In this report, laser action is demonstrated in two such hosts, CaGa{sub 2}S{sub 4} and KPb{sub 2}Cl{sub 5}. The CaGa{sub 2}S{sub 4}:Dy{sup 3+} laser operating at 4.3 {micro}m represents the first sulfide laser operating beyond 2 {micro}m. The KPb{sub 2}Cl{sub 5}:Dy{sup 3+} laser operating at 2.4 {micro}m represents the first operation of a chloride-host laser in ambient conditions. Laser action is also reported for CaGa{sub 2}S{sub 4}:Dy{sup 3+} at 2.4 {micro}m, CaGa{sub 2}S{sub 4}:Dy{sup 3+} at 1.4 {micro}m, and KPb{sub 2}Cl{sub 5}:Nd{sup 3+} at 1.06 {micro}m. Both host materials have been fully characterized, including lifetimes, absorption and emission cross sections, radiative branching ratios, and radiative quantum efficiencies. Radiative branching ratios and radiative quantum efficiencies have been determined both by the Judd-Ofelt method (which is based on absorption measurements), and by a novel method described herein which is based on emission measurements. Modeling has been performed to predict laser performance, and a new method to determine emission cross section from slope efficiency and threshold data is developed. With the introduction and laser demonstration of rare-earth-doped CaGa{sub 2}S{sub 4} and KPb{sub 2}Cl{sub 5}, direct generation of mid-IR laser radiation in a solid-state host has been demonstrated. In

  8. Ceramic Laser Materials

    Directory of Open Access Journals (Sweden)

    Guillermo Villalobos

    2012-02-01

    Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

  9. Ceramic Laser Materials

    Science.gov (United States)

    Sanghera, Jasbinder; Kim, Woohong; Villalobos, Guillermo; Shaw, Brandon; Baker, Colin; Frantz, Jesse; Sadowski, Bryan; Aggarwal, Ishwar

    2012-01-01

    Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements. PMID:28817044

  10. Spectroscopic properties in Er3+-doped germanotellurite glasses and glass ceramics for mid-infrared laser materials

    Science.gov (United States)

    Kang, Shiliang; Xiao, Xiudi; Pan, Qiwen; Chen, Dongdan; Qiu, Jianrong; Dong, Guoping

    2017-03-01

    Transparent Er3+-doped germanotellurite glass ceramics (GCs) with variable Te/Ge ratio were prepared by controllable heat-treated process. X-ray diffraction (XRD) and transmission electron microscope (TEM) confirmed the formation of nanocrystals in glass matrix. Raman spectra were used to investigate the evolution of glass structure and photon energy. Fourier transform infrared (FTIR) spectra were introduced to characterize the change of hydroxyl group (OH‑) content. Enhanced 2.7 μm emission was achieved from Er3+-doped GCs upon excitation with a 980 nm laser diode (LD), and the influence of GeO2 concentration and heat-treated temperature on the spectroscopic properties were also discussed in detail. It is found that the present Er3+-doped GC possesses large stimulated emission cross section at around 2.7 μm (0.85 × 10‑20 cm2). The advantageous spectroscopic characteristics suggest that the obtained GC may be a promising material for mid-infrared fiber lasers.

  11. Spectroscopic properties in Er3+-doped germanotellurite glasses and glass ceramics for mid-infrared laser materials

    Science.gov (United States)

    Kang, Shiliang; Xiao, Xiudi; Pan, Qiwen; Chen, Dongdan; Qiu, Jianrong; Dong, Guoping

    2017-01-01

    Transparent Er3+-doped germanotellurite glass ceramics (GCs) with variable Te/Ge ratio were prepared by controllable heat-treated process. X-ray diffraction (XRD) and transmission electron microscope (TEM) confirmed the formation of nanocrystals in glass matrix. Raman spectra were used to investigate the evolution of glass structure and photon energy. Fourier transform infrared (FTIR) spectra were introduced to characterize the change of hydroxyl group (OH−) content. Enhanced 2.7 μm emission was achieved from Er3+-doped GCs upon excitation with a 980 nm laser diode (LD), and the influence of GeO2 concentration and heat-treated temperature on the spectroscopic properties were also discussed in detail. It is found that the present Er3+-doped GC possesses large stimulated emission cross section at around 2.7 μm (0.85 × 10−20 cm2). The advantageous spectroscopic characteristics suggest that the obtained GC may be a promising material for mid-infrared fiber lasers. PMID:28266570

  12. 1 400-1 500 nm,Different Material-doped Raman Fiber Lasers Pumped by Nd∶YVO4 Laser

    Institute of Scientific and Technical Information of China (English)

    MEI Jin-jie; LIU De-ming; WANG Ying; HUANG De-xiu

    2003-01-01

    Different material-doped Raman fiber lasers with very high efficiency operating in continuous-wave are presented.With 1 W Nd∶YVO4 laser pumping at wavelength of 1 342 nm,single mode output power of above 500 mW (optical-to-optical conversion efficiency of 50%) is simulated in the range of 1 400-1 500 nm.Using high-germanium,high-phosphate and high-borate silicate fibers as the gain medium,laser output at wavelengths of 1 420,1 450,1 480 and 1 495 nm can be achieved with different geometries,which are just as pumping C-band and L-band distributed Raman fiber amplifiers.

  13. Characterization of Tm{sup 3+} doped TNZL glass laser material

    Energy Technology Data Exchange (ETDEWEB)

    Lachheb, R. [Laboratoire Géoressources, Matériaux, Environnement et Changements Globaux, Faculty of Sciences of Sfax, Sfax University, 3018 Sfax (Tunisia); Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, 07743 Jena (Germany); Damak, K., E-mail: Kamel.Damak@fss.rnu.tn [Laboratory of Radio Analysis and Environment, Sfax University, ENIS, 3038 Sfax (Tunisia); Assadi, A.A. [Laboratoire Géoressources, Matériaux, Environnement et Changements Globaux, Faculty of Sciences of Sfax, Sfax University, 3018 Sfax (Tunisia); Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, 07743 Jena (Germany); Herrmann, A. [Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, 07743 Jena (Germany); Yousef, E. [Department of Physics, Faculty of Sciences, Al Azhar University, Assuit branch, Assuit (Egypt); Department of Physics, Faculty of Sciences, King Khalid University, P. O. Box 9004, Abha (Saudi Arabia); Rüssel, C. [Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, 07743 Jena (Germany); Maâlej, R. [Laboratoire Géoressources, Matériaux, Environnement et Changements Globaux, Faculty of Sciences of Sfax, Sfax University, 3018 Sfax (Tunisia)

    2015-05-15

    In this paper, a new tellurite glass (85TeO{sub 2}·5.0Nb{sub 2}O{sub 5}·5.0ZnO·5.0LiF) doped with 1 mol% Tm{sub 2}O{sub 3} was prepared by melt-quenching technique. Differential scanning calorimetry (DSC) measurements indicate a good thermal stability, X-ray diffraction patterns show no sign of crystallization. Precise refractive index measurements were performed on five different wavelengths by a prism spectrometer. The optical energy gap, the Sellmeier energy gap and the dispersion energy were estimated. Judd–Ofelt intensity parameters were evaluated in order to obtain electric and magnetic-dipole transition probabilities, branching ratios and radiative lifetimes of several excited states of Tm{sup 3+}. The classical McCumber theory was used to evaluate the emission cross-sections for the {sup 3}F{sub 4}→{sup 3}H{sub 6} transition at a wavelength of around 1.8 µm. The characteristics of down-conversion luminescence in the visible range were studied by exciting Tm{sup 3+} ions into the {sup 1}G{sub 4} level. Furthermore the structure of this glass was analyzed by Raman spectroscopy. - Highlights: • A new thermally stable tellurite glass (TNZL doped 1 mol% Tm{sup 3+}) was synthesized by a melt-quenching method. • A complete Judd–Ofelt spectroscopic evaluation of the TNZL:Tm glass is presented. • A high gain coefficient and emission cross section are obtained for Tm{sup 3+} in TNZL glass in the 1.8 μm region. • The TNZL:Tm glass would be a potential laser operation around 1.8 μm emission. • TNZL:Tm is a good candidate for generate a blue light for color display devices and light emitting diodes.

  14. Novel materials for laser refrigeration

    Science.gov (United States)

    Hehlen, Markus P.

    2009-02-01

    The status of optical refrigeration of rare-earth-doped solids is reviewed, and the various factors that limit the performance of current laser-cooling materials are discussed. Efficient optical refrigeration is possible in materials for which hωmax 100 ppb are believed to be the main reason for the limited laser-cooling performance in current materials. The many components of doped ZBLAN glass pose particular processing challenges. Binary fluoride glasses such as YF3-LiF are considered as alternatives to ZBLAN, and the crystalline system KPb2Cl5 :Dy3+ is identified as a prime candidate for high-efficiency laser cooling.

  15. Photo-physical Characterisation of Novel Organic Dye-doped Solid-state Laser Materials

    Institute of Scientific and Technical Information of China (English)

    A.Penzkofer; A.Tyagi; T.Susdorf; D.del; Agua; O.García; R.Sastre; A.Costela; I.García-Moreno

    2007-01-01

    1 Results The development of tuneable solid-state organic dye lasers is a subject of considerable interest and research activity.Compared to conventional liquid dye lasers they have the advantage of being free of solvent handling,having small size,and being easy to operate.For high-performance solid-state dye lasers highly photo-stable dyes with low quantum yield of triplet formation and low triplet-triplet absorption cross-section in the lasing wavelength region are required.For solid state dye lasers ...

  16. Cytotoxicity evaluation of dentin contacting materials with dentin barrier test device using erbium-doped yttrium, aluminum, and garnet laser-treated dentin.

    Science.gov (United States)

    Ülker, H E; Ülker, M; Botsalı, M S; Dündar, A; Acar, H

    2014-09-01

    The effect of dentin contacting materials on three-dimensional cultures of pulp-derived cells was evaluated in a dentin barrier test device using erbium-doped yttrium, aluminum, and garnet (Er:YAG) laser-treated dentin. The test materials (iBond(®), G-Bond™, and Vitrebond™) were applied on laser-treated or untreated dentin discs. After 24 h of exposure with perfusion of the test chamber, cell survival was evaluated by enzyme activity and related to a nontoxic control material. The mean values of control tissues were set to represent 100% viability. Data were analyzed using Kruskal-Wallis and Mann-Whitney U test. Vitrebond was the most toxic material for both laser-treated and untreated dentin. On untreated dentin, G-bond was cytotoxic to the pulp-derived cells (p 0.05). However, G-Bond and iBond were not cytotoxic when they were applied to Er:YAG laser-treated dentin (p > 0.05). Er:YAG laser treatment of dentin may protect the pulp cells from toxic substances of dentin contacting restorative materials; however, this effect is material related. Taking into consideration the limitations of this in vitro study, the Er:YAG laser treatment of dentin before restoration might be an option for decreasing the cytotoxic effects of the dental materials. Further research is required for clinical applications. © The Author(s) 2014.

  17. Superconducting doped topological materials

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Satoshi, E-mail: sasaki@sanken.osaka-u.ac.jp [Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Mizushima, Takeshi, E-mail: mizushima@mp.es.osaka-u.ac.jp [Department of Materials Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Department of Physics, Okayama University, Okayama 700-8530 (Japan)

    2015-07-15

    Highlights: • Studies on both normal- and SC-state properties of doped topological materials. • Odd-parity pairing systems with the time-reversal-invariance. • Robust superconductivity in the presence of nonmagnetic impurity scattering. • We propose experiments to identify the existence of Majorana fermions in these SCs. - Abstract: Recently, the search for Majorana fermions (MFs) has become one of the most important and exciting issues in condensed matter physics since such an exotic quasiparticle is expected to potentially give rise to unprecedented quantum phenomena whose functional properties will be used to develop future quantum technology. Theoretically, the MFs may reside in various types of topological superconductor materials that is characterized by the topologically protected gapless surface state which are essentially an Andreev bound state. Superconducting doped topological insulators and topological crystalline insulators are promising candidates to harbor the MFs. In this review, we discuss recent progress and understanding on the research of MFs based on time-reversal-invariant superconducting topological materials to deepen our understanding and have a better outlook on both the search for and realization of MFs in these systems. We also discuss some advantages of these bulk systems to realize MFs including remarkable superconducting robustness against nonmagnetic impurities.

  18. CO2-Doped Diamond: A Potential Solid-State CO2 Laser Material?

    Science.gov (United States)

    Tratt, D.

    1994-01-01

    This paper describes a novel concept for a solid-state CO subscript 2 laser medium which, by eschewing the gas-phase approach, may offer prospects for a compact, robust 9 - 11 (micro)m coherent source, coupled with the potentially superior frequency stability characteristics afforded by monolithic solid-state construction.

  19. Effects of erbium-and chromium-doped yttrium scandium gallium garnet and diode lasers on the surfaces of restorative dental materials: a scanning electron microscope study.

    Science.gov (United States)

    Hatipoglu, M; Barutcigil, C

    2015-01-01

    The aim of this study is to evaluate the potential effects of laser irradiation, which is commonly performed in periodontal surgery, on the surfaces of restorative materials. Five different restorative dental materials were used in this study, as follows: (1) Resin composite, (2) poly acid-modified resin composite (compomer), (3) conventional glass ionomer cement (GIC), (4) resin-modified glass ionomer cement (RMGIC), and (5) amalgam. Four cylindrical samples (8 mm diameter, 2 mm height) were prepared for each restorative material. In addition, four freshly extracted, sound human incisors teeth were selected. Two different laser systems commonly used in periodontal surgery were examined in this study: A 810 nm diode laser at a setting of 1 W with continuous-phase laser irradiation for 10 s, and an erbium-and chromium-doped yttrium scandium gallium garnet (Er, Cr: YSGG) laser at settings of 2.5 W, 3.25 W, and 4 W with 25 Hz laser irradiation for 10 s. Scanning electron microscopy (SEM) analysis was performed to evaluate the morphology and surface deformation of the restorative materials and tooth surfaces. According to the SEM images, the Er, Cr: YSGG laser causes irradiation markings that appear as demineralized surfaces on tooth samples. The Er, Cr: YSGG laser also caused deep defects on composite, compomer, and RMGIC surfaces because of its high power, and the ablation was deeper for these samples. High-magnification SEM images of GIC samples showed the melting and combustion effects of the Er, Cr: YSGG laser, which increased as the laser power was increased. In amalgam samples, neither laser left significant harmful effects at the lowest power setting. The diode laser did cause irradiation markings, but they were insignificant compared with those left by the Er, Cr: YSGG laser on the surfaces of the different materials and teeth. Within the limitations of this study, it can be concluded that Er, Cr: YSGG laser irradiation could cause distortions of the surfaces

  20. Optical and electrical characteristics of chromium- and iron-doped zinc selenide thin film and bulk materials for optically and electrically pumped lasers

    Science.gov (United States)

    Gallian, Andrew

    This work is devoted to evaluating new laser systems based upon chromium and iron doped ZnSe structures. These systems are based upon new materials and pumping schemes. These topics can be broken down into three major subgroups: new materials based upon Cr2+:ZnSe, Fe2+:ZnSe lasers and pump sources, and electrically pumped Cr2+:ZnSe systems. Both hot-pressed ceramic and thin film Cr2+:ZnSe samples were evaluated for their potential as laser gain media. This work entailed spectroscopic analysis of both their absorption and emission spectra as well as characterizing their lifetime of luminescence. For hot-pressed ceramic Cr2+:ZnSe the samples were tested in a laser cavity and proven to be the first laser system in the mid-IR to be demonstrated based upon hot-pressed Cr2+:ZnSe. Thin film Cr2+:ZnSe was determined to have different spectroscopic characteristics for luminescence compared to reference bulk samples. This difference is attributed to the location of all of the optical centers within a Fabry-Perot cavity formed by the film surface and the wafer on which it was deposited. Fe2+:ZnSe laser demonstration at room temperature is presented. This laser operates in a spectral region of great interest for spectroscopy. To develop this laser system new pumping systems were required. Such systems as passively Q-switched Er:YSGG and Stokes Stimulated Raman Scattering from a D2 cell are described in great depth. Electrically pumped Transition Metal 2+:II-VI systems are ideal for small portable spectroscopic and scientific tools. The elimination of an optical pump source removes many complications of other systems including, complications due to having a second laser. This work was approached by modeling electrically motivated transitions with sub-band optical excitation. Lasing of Cr 2+:ZnSe was achieved using a 532 nm pump source. This result, in combination with photo-current and photo-Hall measurements, led to the development of some theories explaining possible

  1. Lasers in materials science

    CERN Document Server

    Ossi, Paolo; Zhigilei, Leonid

    2014-01-01

    This book covers various aspects of lasers in materials science, including a comprehensive overview on basic principles of laser-materials interactions and applications enabled by pulsed laser systems.  The material is organized in a coherent way, providing the reader with a harmonic architecture. While systematically covering the major current and emerging areas of lasers processing applications, the Volume provides examples of targeted modification of material properties achieved through careful control of the processing conditions and laser irradiation parameters. Special emphasis is placed on specific strategies aimed at nanoscale control of material structure and properties to match the stringent requirements of modern applications.  Laser fabrication of novel nanomaterials, which expands to the domains of photonics, photovoltaics, sensing, and biomedical applications, is also discussed in the Volume. This book assembles chapters based on lectures delivered at the Venice International School on Lasers...

  2. Novel materials for laser refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Hehlen, Markus P [Los Alamos National Laboratory

    2009-01-01

    The status of optical refrigeration of rare-earth-doped solids is reviewed, and the various factors that limit the performance of current laser-cooling materials are discussed. Efficient optical refrigeration is possible in materials for which {Dirac_h}{omega}{sub max} < E{sub p}/8, where {Dirac_h}{omega}{sub max} is the maximum phonon energy of the host material and E{sub p} is the pump energy of the rare-earth dopant. Transition-metal and OH{sup -}impurities at levels >100 ppb are believed to be the main factors for the limited laser-cooling performance in current materials. The many components of doped ZBLAN glass pose particular processing challenges. Binary fluoride glasses such as YF{sub 3}-LiF are considered as alternatives to ZBLAN. The crystalline system KPb{sub 2}CI{sub 5} :Dy{sup 3+} is identified as a prime candidate for high-efficiency laser cooling.

  3. Ceramic laser materials

    Science.gov (United States)

    Ikesue, Akio; Aung, Yan Lin

    2008-12-01

    The word 'ceramics' is derived from the Greek keramos, meaning pottery and porcelain. The opaque and translucent cement and clay often used in tableware are not appropriate for optical applications because of the high content of optical scattering sources, that is, defects. Recently, scientists have shown that by eliminating the defects, a new, refined ceramic material - polycrystalline ceramic - can be produced. This advanced ceramic material offers practical laser generation and is anticipated to be a highly attractive alternative to conventional glass and single-crystal laser technologies in the future. Here we review the history of the development of ceramic lasers, the principle of laser generation based on this material, some typical results achieved with ceramic lasers so far, and discuss the potential future outlook for the field.

  4. Development of Ceramic Solid-State Laser Host Material

    Science.gov (United States)

    Prasad, Narasimha S.; Trivedi, Sudhir; Kutcher, Susan; Wang, Chen-Chia; Kim, Joo-Soo; Hommerich, Uwe; Shukla, Vijay; Sadangi, Rajendra

    2009-01-01

    Polycrystalline ceramic laser materials are gaining importance in the development of novel diode-pumped solid-state lasers. Compared to single-crystals, ceramic laser materials offer advantages in terms of ease of fabrication, shape, size, and control of dopant concentrations. Recently, we have developed Neodymium doped Yttria (Nd:Y2O3) as a solid-state ceramic laser material. A scalable production method was utilized to make spherical non agglomerated and monodisperse metastable ceramic powders of compositions that were used to fabricate polycrystalline ceramic material components. This processing technique allowed for higher doping concentrations without the segregation problems that are normally encountered in single crystalline growth. We have successfully fabricated undoped and Neodymium doped Yttria material up to 2" in diameter, Ytterbium doped Yttria, and erbium doped Yttria. We are also in the process of developing other sesquioxides such as scandium Oxide (Sc2O3) and Lutesium Oxide (Lu2O3) doped with Ytterbium, erbium and thulium dopants. In this paper, we present our initial results on the material, optical, and spectroscopic properties of the doped and undoped sesquioxide materials. Polycrystalline ceramic lasers have enormous potential applications including remote sensing, chem.-bio detection, and space exploration research. It is also potentially much less expensive to produce ceramic laser materials compared to their single crystalline counterparts because of the shorter fabrication time and the potential for mass production in large sizes.

  5. Gas Immersion Laser Doping for superconducting nanodevices

    Energy Technology Data Exchange (ETDEWEB)

    Chiodi, F. [Institut d’Electronique Fondamentale, CNRS-Université Paris-Sud, F-91405 Orsay (France); Grockowiak, A. [Institut Néel, CNRS, BP 166, F-38042 Grenoble (France); CEA, INAC, UMR-E9001/UJF, LATEQS, 17 Rue des Martyrs, F-38054 Grenoble (France); Duvauchelle, J.E. [CEA, INAC, UMR-E9001/UJF, LATEQS, 17 Rue des Martyrs, F-38054 Grenoble (France); Fossard, F. [Institut d’Electronique Fondamentale, CNRS-Université Paris-Sud, F-91405 Orsay (France); Lefloch, F. [CEA, INAC, UMR-E9001/UJF, LATEQS, 17 Rue des Martyrs, F-38054 Grenoble (France); Klein, T. [Institut Néel, CNRS, BP 166, F-38042 Grenoble (France); Marcenat, C. [CEA, INAC, UMR-E9001/UJF, LATEQS, 17 Rue des Martyrs, F-38054 Grenoble (France); Institut Néel, CNRS, BP 166, F-38042 Grenoble (France); Débarre, D. [Institut d’Electronique Fondamentale, CNRS-Université Paris-Sud, F-91405 Orsay (France)

    2014-05-01

    We have conceived and fabricated Superconductor/Normal metal/Superconductor Josephson junctions made entirely of boron doped Silicon. We have used Gas Immersion Laser Doping to fabricate SN bilayers with good ohmic interfaces and well controlled concentration and doping depth. Standard fabrication processes, optimised for silicon, were employed to nanostructure the bilayers without affecting their transport properties. The junctions thus fabricated are proximity superconducting and show well understood I–V characteristics. This research opens the road to all-silicon, non-dissipative, Josephson Field Effect Transistors.

  6. Ceramic Laser Materials

    Energy Technology Data Exchange (ETDEWEB)

    Soules, T F; Clapsaddle, B J; Landingham, R L; Schaffers, K I

    2005-02-15

    Transparent ceramic materials have several major advantages over single crystals in laser applications, not the least of which is the ability to make large aperture parts in a robust manufacturing process. After more than a decade of working on making transparent YAG:Nd, Japanese workers have recently succeeded in demonstrating samples that performed as laser gain media as well as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. We have established a good working relationship with Konoshima Ltd., the Japanese producer of the best ceramic laser materials, and have procured and evaluated slabs designed by us for use in our high-powered SSHCL. Our measurements indicate that these materials will work in the SSHCL, and we have nearly completed retrofitting the SSHCL with four of the largest transparent ceramic YAG:Nd slabs in existence. We have also begun our own effort to make this material and have produced samples with various degrees of transparency/translucency. We are in the process of carrying out an extensive design-of-experiments to establish the significant process variables for making transparent YAG. Finally because transparent ceramics afford much greater flexibility in the design of lasers, we have been exploring the potential for much larger apertures, new materials, for example for the Mercury laser, other designs for SSHL, such as, edge pumping designs, slabs with built in ASE suppression, etc. This work has just beginning.

  7. Laser processing of materials

    Indian Academy of Sciences (India)

    J Dutta Majumdar; I Manna

    2003-06-01

    Light amplification by stimulated emission of radiation (laser) is a coherent and monochromatic beam of electromagnetic radiation that can propagate in a straight line with negligible divergence and occur in a wide range of wavelength, energy/power and beam-modes/configurations. As a result, lasers find wide applications in the mundane to the most sophisticated devices, in commercial to purely scientific purposes, and in life-saving as well as life-threatening causes. In the present contribution, we provide an overview of the application of lasers for material processing. The processes covered are broadly divided into four major categories; namely, laser-assisted forming, joining, machining and surface engineering. Apart from briefly introducing the fundamentals of these operations, we present an updated review of the relevant literature to highlight the recent advances and open questions. We begin our discussion with the general applications of lasers, fundamentals of laser-matter interaction and classification of laser material processing. A major part of the discussion focuses on laser surface engineering that has attracted a good deal of attention from the scientific community for its technological significance and scientific challenges. In this regard, a special mention is made about laser surface vitrification or amorphization that remains a very attractive but unaccomplished proposition.

  8. Laser materials production

    Science.gov (United States)

    Gianinoni, I.; Musci, M.

    1985-09-01

    The characteristics and the perspectives of the new photochemical laser techniques for materials production will be briefly analysed and some recent experimental results both on large area deposition of thin films and on synthesis of powders will be reported. As an example of an IR laser process, the cw CO 2 laser-induced deposition of hydrogenated amorphous silicon will be described in some detail. The results of some UV experiments for semiconductor, metal and insulating film depositions will also be discussed. The features of the process for laser-driven synthesis of powders and the characteristics of the produced particles will be evidenced, and some of their technological applications will be outlined. The requirements of the laser sources suitable for this kind of applications are in general the same as in gas-phase laser chemistry, however it will be pointed out how some parameters are more significant for this specific use.

  9. Growth of doped silicon nanowires by pulsed laser deposition and their analysis by electron beam induced current imaging

    Energy Technology Data Exchange (ETDEWEB)

    Eisenhawer, B; Berger, A; Christiansen, S [Institute of Photonic Technology, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Zhang, D; Clavel, R [Laboratory of Robotic Systems, Ecole Polytechnique Federale de Lausanne (EPFL), Station 9, CH-1015 Lausanne (Switzerland); Michler, J, E-mail: bjoern.eisenhawer@ipht-jena.de [Mechanics of Materials and Nanostructures Laboratory, EMPA-Materials Science and Technology, Feuerwerkstrasse 39, CH-3602 Thun (Switzerland)

    2011-02-18

    Doped silicon nanowires (NWs) were epitaxially grown on silicon substrates by pulsed laser deposition following a vapour-liquid-solid process, in which dopants together with silicon atoms were introduced into the gas phase by laser ablation of lightly and highly doped silicon target material. p-n or p{sup ++}-p junctions located at the NW-silicon substrate interfaces were thus realized. To detect these junctions and visualize them the electron beam induced current technique and two-point probe current-voltage measurements were used, based on nanoprobing individual silicon NWs in a scanning electron microscope. Successful silicon NW doping by pulsed laser deposition of doped target material could experimentally be demonstrated. This doping strategy compared to the commonly used doping from the gas phase during chemical vapour deposition is evaluated essentially with a view to potentially overcoming the limitations of chemical vapour deposition doping, which shows doping inhomogeneities between the top and bottom of the NW as well as between the core and shell of NWs and structural lattice defects, especially when high doping levels are envisaged. The pulsed laser deposition doping technique yields homogeneously doped NWs and the doping level can be controlled by the choice of the target material. As a further benefit, this doping procedure does not require the use of poisonous gases and may be applied to grow not only silicon NWs but also other kinds of doped semiconductor NWs, e.g. group III nitrides or arsenides.

  10. Mirror reflectivity and doping considerations for high performance oxide-confined vertical cavity lasers

    Energy Technology Data Exchange (ETDEWEB)

    Geib, K.M.; Choquette, K.D.; Chui, H.C.; Hou, H.Q.; Hammons, B.E.

    1996-01-01

    We report the effects of mirror doping and reflectivity in 850 and 780 nm oxide-confined vertical cavity surface emitting lasers. Decreased doping throughout the n-type mirror produces significantly higher quantum efficiency, while the optimum reflectivity is dependent upon the gain material.

  11. Hybrid laser technology and doped biomaterials

    Science.gov (United States)

    Jelínek, Miroslav; Zemek, Josef; Remsa, Jan; Mikšovský, Jan; Kocourek, Tomáš; Písařík, Petr; Trávníčková, Martina; Filová, Elena; Bačáková, Lucie

    2017-09-01

    Hybrid laser-based technologies for deposition of new types of doped thin films are presented. The focus is on arrangements combining pulsed laser deposition (PLD) with magnetron sputtering (MS), and on the setup with two simultaneously running PLD systems (dual PLD). Advantages and disadvantages of both arrangements are discussed. Layers of different dopants concentration were prepared. Experience with deposition of chromium and titanium doped diamond-like carbon (DLC) films for potential coating of bone implants is presented. Properties of the layers prepared by both technologies are compared and discussed. The suitability of the layers for colonization with human bone marrow mesenchymal stem cells and human osteoblast-like cells, were also evaluated under in vitro conditions.

  12. Ion Doped Quantum Well Lasers

    Science.gov (United States)

    1993-04-01

    5 3 TGA analysis of {N[Si(CH3)312)3Er ................................. 5 4 Spectroscopic analysis of {N[Si(CH3)3]2)3Er...40o 56o 6oo TEMPERATURE (-C) Figure 3 TGA analysis of Er{NISi(CH3)3J]J 3 . CHEMICAL VAPOR DEPOSITION As the objective of this work is to dope A1GaAs...laO0 23633 47.870C 99.37% 1,14.84*C s00, • 95.212 173.75C 90.622 EI 800.77C 20- 60- 2o256. tC 0 i9o 360 460 560 600 TEMPERATURE (’C) Figure 3 TGA

  13. [Study on Spectral Characteristics of Two Kinds of Home-Made Novel Yb-Doped Fluoride Laser Crystals].

    Science.gov (United States)

    Xu, Wen-bin; Chai, Lu; Shi, Jun-kai; Song, You-jian; Hu, Ming-lie; Wang, Qing-yue; Su, Liang-bi; Jiang, Da-peng; Xu, Jun

    2015-09-01

    Yb-doped fluoride crystals are of important another Yb-doped laser materials besides Yb-doped oxide, which are becoming one of interests for developing tunable lasers and ultrafast lasers. In this paper, the systematic and contrastive experiments of the optical spectral characteristics are presented for two types of home-made novel Yb-doped fluoride laser crystals, namely, Yb-doped CaF2-SrF2 mixed crystal and co-doped Yb, Y:CaF2 single crystal. The fluorescent features of Yb-doped CaF2-SrF2 mixed crystal and co-doped Yb, Y:CaF2 single crystal are apparently different by the fluorescence experiment. The physical mechanism of these fluorescence spectra were analyzed and proposed. The influence of doping concentrations of active Yb(3+) ions or co-doping Y ions on the absorption of Yb-doped CaF2-SrF2 mixed crystal and co-doped Yb, Y:CaF2 single crystal was experimentally investigated, and the optimal values of doping concentrations of active Yb(3+) ions or co-doping Y ions in the two types of fluoride laser crystals were obtained. Continuous-wave laser operation for the two novel fluoride laser crystals has been achieved in three-mirror-folded resonator using a laser diode as the pump source. Therein, the laser operation for the co-doped Yb, Y:CaF2 crystal is demonstrated for the first time. For the two types of fluoride laser crystals (four samples), the input-output power relational curves, the optical slope efficiencies and the laser spectra were demonstrated by the laser experiments. By comparisons between the two types of fluoride laser crystals in the absorbability, fluorescence and laser spectra, laser threshold and slope efficiency of the continuous-wave laser operation, the results show that the best one of the four samples in spectral and laser characteristics is co-doped 3at%Yb, 6at% Y:CaF2 single crystal, which has an expected potential in the application. The research results provide available references for improving further laser performance of Yb-doped

  14. Tm3+/Yb3+ co-doped tellurite glass with silver nanoparticles for 1.85 μm band laser material

    Science.gov (United States)

    Huang, Bo; Zhou, Yaxun; Cheng, Pan; Zhou, Zizhong; Li, Jun; Jin, Wei

    2016-10-01

    Tm3+/Yb3+ co-doped tellurite glasses with different silver nanoparticles (Ag NPs) concentrations were prepared using the conventional melt-quenching technique and characterized by the UV/Vis/NIR absorption spectra, 1.85 μm band fluorescence emission spectra, transmission electron microscopy (TEM) images, differential scanning calorimeter (DSC) curves and X-ray diffraction (XRD) patterns to investigate the effects of Ag NPs on the 1.85 μm band spectroscopic properties of Tm3+ ions, thermal stability and structural nature of glass hosts. Under the excitation of 980 nm laser diode (LD), the 1.85 μm band fluorescence emission of Tm3+ ions enhances significantly in the presence of Ag NPs with average diameter of ∼8 nm and local surface Plasmon resonance (LSPR) band of ∼590 nm, which is mainly attributed to the increased local electric field induced by Ag NPs at the proximity of doped rare-earth ions on the basis of energy transfer from Yb3+ to Tm3+ ions. An improvement by about 110% of fluorescence intensity is observed in the Tm3+/Yb3+ co-doped tellurite glass containing 0.5 mol% amount of AgNO3 while the prepared glass samples possess good thermal stability and amorphous structural nature. Meanwhile, the Judd-Ofelt intensity parameters Ωt (t = 2,4,6), spontaneous radiative transition probabilities, fluorescence branching ratios and radiative lifetimes of relevant excited levels of Tm3+ ions were determined based on the Judd-Ofelt theory to reveal the enhanced effects of Ag NPs on the 1.85 μm band spectroscopic properties, and the energy transfer micro-parameters and phonon contribution ratios were calculated based on the non-resonant energy transfer theory to elucidate the energy transfer mechanism between Yb3+ and Tm3+ ions. The present results indicate that the prepared Tm3+/Yb3+ co-doped tellurite glass with an appropriate amount of Ag NPs is a promising lasing media applied for 1.85 μm band solid-state lasers and amplifiers.

  15. Nanocrystalline Cr(2+)-doped ZnSe nanowires laser.

    Science.gov (United States)

    Feng, Guoying; Yang, Chao; Zhou, Shouhuan

    2013-01-09

    By using femtosecond laser pulses to ablate microsized targets that are dispersed in liquid media, nanocrystalline Cr(2+)-doped ZnSe nanowires have been successfully fabricated for the first time. The phase and stoichiometries of the original materials are preserved while the sizes are reduced down to 30-120 nm for these nanowires. X-ray diffraction results show that the products are nanocrystalline ZnSe with cubic sphalerite structure. Scanning electron microscope results indicate that the products be ZnSe nanowires. The nanowires are usually 30-120 nm in diameter and several tens of micrometers in length. Photoluminescence of the nanocrystalline Cr(2+)-doped ZnSe nanowires shows strong emission at around 2000-2500 nm under excitation of 1300-2250 nm wavelength at room temperature. By using the Cr(2+)-doped ZnSe multiple nanowires as the gain medium, mid-infrared oscillation at 2194 nm has been established. The oscillation wavelength of the multiple nanowires laser is 150 nm shifted to shorter wavelengths in comparison with that of microsized powder random laser.

  16. Growth of arrays of Al-doped ZnO nanocones by pulsed laser deposition.

    Science.gov (United States)

    Sun, Ye; Addison, Katherine E; Ashfold, Michael N R

    2007-12-12

    Arrays of aligned Al-doped ZnO nanocones have been synthesized by pulsed laser deposition following excimer laser ablation of a ceramic ZnO target containing 2% Al(2)O(3) (by weight). The elemental composition, microstructural and optical properties of the products were examined by laser induced breakdown spectroscopy, electron microscopy, x-ray diffraction and room temperature photoluminescence measurements. The incident laser fluence was identified as a key parameter in nanocone formation. Their tapered morphologies and small tip diameters (approximately 5 nm) suggest that Al-doped ZnO nanocones could find application as field emitters and as a gas sensing material.

  17. New laser materials for laser diode pumping

    Science.gov (United States)

    Jenssen, H. P.

    1990-01-01

    The potential advantages of laser diode pumped solid state lasers are many with high overall efficiency being the most important. In order to realize these advantages, the solid state laser material needs to be optimized for diode laser pumping and for the particular application. In the case of the Nd laser, materials with a longer upper level radiative lifetime are desirable. This is because the laser diode is fundamentally a cw source, and to obtain high energy storage, a long integration time is necessary. Fluoride crystals are investigated as host materials for the Nd laser and also for IR laser transitions in other rare earths, such as the 2 micron Ho laser and the 3 micron Er laser. The approach is to investigate both known crystals, such as BaY2F8, as well as new crystals such as NaYF8. Emphasis is on the growth and spectroscopy of BaY2F8. These two efforts are parallel efforts. The growth effort is aimed at establishing conditions for obtaining large, high quality boules for laser samples. This requires numerous experimental growth runs; however, from these runs, samples suitable for spectroscopy become available.

  18. Laser machining of advanced materials

    CERN Document Server

    Dahotre, Narendra B

    2011-01-01

    Advanced materialsIntroductionApplicationsStructural ceramicsBiomaterials CompositesIntermetallicsMachining of advanced materials IntroductionFabrication techniquesMechanical machiningChemical Machining (CM)Electrical machiningRadiation machining Hybrid machiningLaser machiningIntroductionAbsorption of laser energy and multiple reflectionsThermal effectsLaser machining of structural ceramicsIntrodu

  19. Laser and nonlinear optical materials

    Energy Technology Data Exchange (ETDEWEB)

    De Shazer, L.G.

    1986-01-01

    This book contains 21 papers. Some of the titles are: Frequency conversion materials from a device perspective; Recent developments in area; Recent developments in barium borate; Growth of laser crystals at Airtron; Crystal growth and the future of solid state lasers; Faraday rotator materials for laser systems; and Mechanical properties of single crystal ceramics.

  20. Femtosecond Laser Crystallization of Boron-doped Amorphous Hydrogenated Silicon Films

    Directory of Open Access Journals (Sweden)

    P.D. Rybalko

    2016-10-01

    Full Text Available Crystallization of amorphous hydrogenated silicon films with femtosecond laser pulses is one of the promising ways to produce nanocrystalline silicon for photovoltaics. The structure of laser treated films is the most important factor determining materials' electric and photoelectric properties. In this work we investigated the effect of femtosecond laser irradiation of boron doped amorphous hydrogenated silicon films with different fluences on crystalline volume fraction and electrical properties of this material. A sharp increase of conductivity and essential decrease of activation energy of conductivity temperature dependences accompany the crystallization process. The results obtained are explained by increase of boron doping efficiency in crystalline phase of modified silicon film.

  1. Single-mode biological distributed feedback lasers based on vitamin B2 doped gelatin

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Maier-Flaig, F.; Lemmer, U.

    Biological second-order distributed feedback (DFB) lasers are presented. Riboflavin (vitamin B2) doped gelatin as active material is spin-coated onto nanoimprinted polymer with low refractive index. DFB grating periods of 368 nm and 384 nm yield laser emission at 543 nm and 562 nm, respectively....

  2. Single-mode biological distributed feedback lasers based on vitamin B2 doped gelatin

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Maier-Flaig, F.; Lemmer, U.

    Biological second-order distributed feedback (DFB) lasers are presented. Riboflavin (vitamin B2) doped gelatin as active material is spin-coated onto nanoimprinted polymer with low refractive index. DFB grating periods of 368 nm and 384 nm yield laser emission at 543 nm and 562 nm, respectively....

  3. Tungsten diselenide Q-switched erbium-doped fiber laser

    Science.gov (United States)

    Chen, Bohua; Zhang, Xiaoyan; Guo, Chaoshi; Wu, Kan; Chen, Jianping; Wang, Jun

    2016-08-01

    We report a tungsten diselenide (WSe2) polyvinyl alcohol (PVA)-based, saturable absorber and related experiment results of a Q-switched fiber laser. WSe2-PVA film is synthesized by liquid phase exfoliation method, and its saturable absorption is measured via a nonlinear transmission experiment. The result shows that WSe2-PVA saturable absorber has a modulation depth of 3.5%, which means it has potential for generating an ultrafast pulse laser. We apply this absorber into a ring-cavity erbium-doped fiber laser and obtain Q-switched pulses under appropriate pump power. Our work demonstrates the reliable nonlinear optical characteristics of WSe2 and the feasibility for this two-dimensional material to be applied in the field of nonlinear optics.

  4. Optimization of spectroscopic properties of ytterbium-doped laser glasses

    Institute of Scientific and Technical Information of China (English)

    姜淳[1; 张俊洲[2; 邓佩珍[3; 黄国松[4; 毛涵芬[5; 干福熹[6

    1999-01-01

    Four laser glasses with high emission cross sections are experimentally obtained. The laser performance parameters are determined from the spectroscopic parameters of these glasses and compared with those of developing laser glasses abroad. It is shown that Yb3--doped telluorogermanate, Yb3+-doped niobosilicate glasses have the highest emission cross section and gain coefficient, the smallest minimum pumping intensity and saturation pumping intensity, and the lowest minimum fraction of excited ions. Yb3+-doped borate glass follows just behind them. These glasses have some spectroscopic advantages over laser glasses developed recently elsewhere. Yb3+-doped phosphate glass is comparable to phosphate laser glass which had high emission cross section and was developed recently by HOYA Corporation in Japan.The domestic glasses with optimum spectroscopic properties may be promising candidates for applications in high-average power and high-peak power solid state lasers, especially laser for the ne

  5. Optical Waveguide Property of Nd-doped Laser Materials Ndx Y1-x A13(BO3) 4 and Nd∶MgO∶LiNbO3

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Lanthanide has attracted much attention in the field of optical communications in recent years. Some property analyses on optical waveguide of Nd-doped crystal NdxY1-xA13(BO3)4 and Nd∶MgO∶LiNbO3 are made in this paper, followed by introduction of the methods of experimentation and theoretical calculation for the planar optical waveguides. The refractive index profiles of the optical waveguides are analyzed. The above work offers useful information for study on new type materials for optical communications.

  6. Local doping of two-dimensional materials

    Science.gov (United States)

    Wong, Dillon; Velasco, Jr, Jairo; Ju, Long; Kahn, Salman; Lee, Juwon; Germany, Chad E.; Zettl, Alexander K.; Wang, Feng; Crommie, Michael F.

    2016-09-20

    This disclosure provides systems, methods, and apparatus related to locally doping two-dimensional (2D) materials. In one aspect, an assembly including a substrate, a first insulator disposed on the substrate, a second insulator disposed on the first insulator, and a 2D material disposed on the second insulator is formed. A first voltage is applied between the 2D material and the substrate. With the first voltage applied between the 2D material and the substrate, a second voltage is applied between the 2D material and a probe positioned proximate the 2D material. The second voltage between the 2D material and the probe is removed. The first voltage between the 2D material and the substrate is removed. A portion of the 2D material proximate the probe when the second voltage was applied has a different electron density compared to a remainder of the 2D material.

  7. New ytterbium-doped apatite crystals for flexible laser design

    Energy Technology Data Exchange (ETDEWEB)

    Payne, S.A.; DeLoach, L.D.; Smith, L.K.; Krupke, W.F. [Lawrence Livermore National Lab., CA (United States); Chai, B.H.T.; Loutts, G. [Univ. of Central Florida, Orlando, FL (United States). Center for Research and Education in Optics and Lasers

    1994-03-01

    A new class of Yb-lasers is summarized in this article. The apatite family of crystals has been found to impose favorable spectroscopic and laser properties on the Yb{sup 3+} activator ion. Crystals of Yb-doped Ca{sub 5}(PO{sub 4}){sub 3}F, Sr{sub 5}(PO{sub 4}){sub 3}F, Ca{sub x}Sr{sub 5{minus}x}(PO{sub 4}){sub 3}F, and Sr{sub 5}(VO{sub 4}){sub 3}F have been grown and investigated. Several useful laser crystals have been identified which offer a variety of fundamental laser parameters for designing diode-pumped systems. In general, this class of materials is characterized by high emission cross sections (3.6--13.1 {times} 10{sup {minus}20} cm{sup 2}), useful emission lifetimes (0.59--1.26 msec), a strong pump band ({sigma}{sub abs} = 2.0--10.0 {times} 10{sup {minus}20} cm{sup 2}) and pump and extraction wavelengths near 900 and 1,045 nm, respectively. Efficient lasing has been demonstrated for several of the members of this class of materials, and high optical quality crystals have been grown by the Czochralski method.

  8. Laser cutting plastic materials

    Energy Technology Data Exchange (ETDEWEB)

    Van Cleave, R.A.

    1980-08-01

    A 1000-watt CO/sub 2/ laser has been demonstrated as a reliable production machine tool for cutting of plastics, high strength reinforced composites, and other nonmetals. More than 40 different plastics have been laser cut, and the results are tabulated. Applications for laser cutting described include fiberglass-reinforced laminates, Kevlar/epoxy composites, fiberglass-reinforced phenolics, nylon/epoxy laminates, ceramics, and disposable tooling made from acrylic.

  9. Monolithic Rare Earth Doped PTR Glass Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The main goal of the project is to demonstrate the feasibility of a monolithic solid state laser on the basis of PTR glass co-doped with luminescent rare earth ions....

  10. Synchronous Chaos Generation in an ^-Doped Fiber Laser System

    National Research Council Canada - National Science Library

    Gomez-Pavon, L. C; Munoz-Pacheco, J. M; Luis-Ramos, A

    2015-01-01

    ...+ -doped fiber lasers is experimentally analyzed. Using a single amplitude modulator in the system, synchronous chaos generation is obtained at two different modulation frequencies, i.e., 10.38 and 3.85 MHz...

  11. Doping He droplets by laser ablation with a pulsed supersonic jet source

    Energy Technology Data Exchange (ETDEWEB)

    Katzy, R.; Singer, M.; Izadnia, S.; LaForge, A. C., E-mail: aaron.laforge@physik.uni-freiburg.de; Stienkemeier, F. [Physikalisches Institut, Universität Freiburg, 79104 Freiburg (Germany)

    2016-01-15

    Laser ablation offers the possibility to study a rich number of atoms, molecules, and clusters in the gas phase. By attaching laser ablated materials to helium nanodroplets, one can gain highly resolved spectra of isolated species in a cold, weakly perturbed system. Here, we present a new setup for doping pulsed helium nanodroplet beams by means of laser ablation. In comparison to more well-established techniques using a continuous nozzle, pulsed nozzles show significant differences in the doping efficiency depending on certain experimental parameters (e.g., position of the ablation plume with respect to the droplet formation, nozzle design, and expansion conditions). In particular, we demonstrate that when the ablation region overlaps with the droplet formation region, one also creates a supersonic beam of helium atoms seeded with the sample material. The processes are characterized using a surface ionization detector. The overall doping signal is compared to that of conventional oven cell doping showing very similar dependence on helium stagnation conditions, indicating a comparable doping process. Finally, the ablated material was spectroscopically studied via laser induced fluorescence.

  12. A unidirectional Er3+-doped fiber ring laser without isolator

    DEFF Research Database (Denmark)

    Shi, Yuan; Sejka, Milan; Poulsen, Ove

    1995-01-01

    An Er3+-doped fiber ring laser with unidirectional operation without optical isolator has been investigated for different cavity conditions. The fiber ring laser cavity is built in such a way that the optical fields propagating in the two directions suffer different losses. As a consequence, the ......, the laser oscillation appears in a quasi-unidirectional form. By incorporating a fiber pigtailed bandpass filter to enhance mode competition, a purely unidirectional tunable fiber ring laser is obtained with high efficiency and broad tunability...

  13. Measurement of the figure of merit of indigenously developed Nd-doped phosphate laser glass rods for use in high power lasers

    Indian Academy of Sciences (India)

    A P Kulkarni; S Jain; M P Kamath; A S Joshi; P A Naik; P D Gupta; K Annapurna; A K Mandal; B Karmakar; R Sen

    2014-01-01

    High energy, high power (HEHP) Nd:glass laser systems are used for inertial confinement fusion and equation of state (EOS) studies of materials at high temperature and pressure. A program has been undertaken for the indigenous development of Nd-doped phosphate laser glass rods and discs for HEHP lasers. In this paper, we report the characterization of the Nd-doped phosphate laser glass rods produced under this program and compare the indigenously developed laser glass to LHG-8 laser glass of M/s Hoya, Japan. We experimentally measured the values of the stimulated emission cross-section () and coefficient of intensity-dependent refractive index (2) and hence the figure of merit = /2 of the indigenous phosphate laser glass rods. This value of figure of merit is found comparable to the reported value of identically doped Nd:glass rods.

  14. Two-photon-induced internal modification of silicon by erbium-doped fiber laser.

    Science.gov (United States)

    Verburg, P C; Römer, G R B E; Huis In 't Veld, A J

    2014-09-08

    Three-dimensional bulk modification of dielectric materials by multiphoton absorption of laser pulses is a well-established technology. The use of multiphoton absorption to machine bulk silicon has been investigated by a number of authors using femtosecond laser sources. However, no modifications confined in bulk silicon, induced by multiphoton absorption, have been reported so far. Based on results from numerical simulations, we employed an erbium-doped fiber laser operating at a relatively long pulse duration of 3.5 nanoseconds and a wavelength of 1549 nm for this process. We found that these laser parameters are suitable to produce modifications at various depths inside crystalline silicon.

  15. Multiwavelength erbium-doped fiber laser exploiting intracavity polarization inhomogeneity

    Institute of Scientific and Technical Information of China (English)

    孙军强; 丘军林; 黄德修

    2000-01-01

    Simultaneous multiwavelength lasing is demonstrated exploiting intracavity polarization in-homogeneity in an erbium-doped fiber laser. Experiments indicate that polarization hole burning can be enhanced by the changes of optical MQW waveguide bias current and the polarization states in the laser cavity. Ten wavelengths with 0.9 nm spacing are generated at room temperature.

  16. Terahertz Raman laser based on silicon doped with phosphorus

    NARCIS (Netherlands)

    Pavlov, S. G.; Hubers, H. W.; Bottger, U.; Zhukavin, R. K.; Shastin, V. N.; Hovenier, J. N.; Redlich, B.; Abrosimov, N. V.; Riemann, H.

    2008-01-01

    Raman-type stimulated emission at frequencies between 5.0 and 5.2 THz as well as between 6.1 and 6.4 THz has been realized in silicon crystals doped by phosphorus donors. The Raman laser operates at around 5 K under optical excitation by a pulsed, frequency-tunable infrared free electron laser. The

  17. Multiwavelength erbium-doped fiber laser exploiting intracavity polarization inhomogeneity

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Simultaneous multiwavelength lasing is demonstrated exploiting intracavity polarization inhomogeneity in an erbium-doped fiber laser. Experiments indicate that polarization hole burning can be enhanced by the changes of optical MQW waveguide bias current and the polarization states in the laser cavity. Ten wavelengths with 0.9 nm spacing are generated at room temperature.

  18. Tungsten-doped thin film materials

    Science.gov (United States)

    Xiang, Xiao-Dong; Chang, Hauyee; Gao, Chen; Takeuchi, Ichiro; Schultz, Peter G.

    2003-12-09

    A dielectric thin film material for high frequency use, including use as a capacitor, and having a low dielectric loss factor is provided, the film comprising a composition of tungsten-doped barium strontium titanate of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3, where X is between about 0.5 and about 1.0. Also provided is a method for making a dielectric thin film of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3 and doped with W, where X is between about 0.5 and about 1.0, a substrate is provided, TiO.sub.2, the W dopant, Ba, and optionally Sr are deposited on the substrate, and the substrate containing TiO.sub.2, the W dopant, Ba, and optionally Sr is heated to form a low loss dielectric thin film.

  19. Laser-Material Interactions

    Science.gov (United States)

    1989-09-01

    from the spinner to the PL measurement setup, the time lapse before PL data collection being - 2-3 minutes. The deposition of sodium sulfide nano ...limitations of tsig u existing surface-emitting laser designs, particula .rly the I n this paper, we describe implementation of the novel i.diu; *high

  20. Laser annealed in-situ P-doped Ge for on-chip laser source applications (Conference Presentation)

    Science.gov (United States)

    Srinivasan, Ashwyn; Pantouvaki, Marianna; Shimura, Yosuke; Porret, Clement; Van Deun, Rik; Loo, Roger; Van Thourhout, Dries; Van Campenhout, Joris

    2016-05-01

    Realization of a monolithically integrated on-chip laser source remains the holy-grail of Silicon Photonics. Germanium (Ge) is a promising semiconductor for lasing applications when highly doped with Phosphorous (P) and or alloyed with Sn [1, 2]. P doping makes Ge a pseudo-direct band gap material and the emitted wavelengths are compatible with fiber-optic communication applications. However, in-situ P doping with Ge2H6 precursor allows a maximum active P concentration of 6×1019 cm-3 [3]. Even with such active P levels, n++ Ge is still an indirect band gap material and could result in very high threshold current densities. In this work, we demonstrate P-doped Ge layers with active n-type doping beyond 1020 cm-3, grown using Ge2H6 and PH3 and subsequently laser annealed, targeting power-efficient on-chip laser sources. The use of Ge2H6 precursors during the growth of P-doped Ge increases the active P concentration level to a record fully activated concentration of 1.3×1020 cm-3 when laser annealed with a fluence of 1.2 J/cm2. The material stack consisted of 200 nm thick P-doped Ge grown on an annealed 1 µm Ge buffer on Si. Ge:P epitaxy was performed with PH3 and Ge2H6 at 320oC. Low temperature growth enable Ge:P epitaxy far from thermodynamic equilibrium, resulting in an enhanced incorporation of P atoms [3]. At such high active P concentration, the n++ Ge layer is expected to be a pseudo-direct band gap material. The photoluminescence (PL) intensities for layers with highest active P concentration show an enhancement of 18× when compared to undoped Ge grown on Si as shown in Fig. 1 and Fig. 2. The layers were optically pumped with a 640 nm laser and an incident intensity of 410 mW/cm2. The PL was measured with a NIR spectrometer with a Hamamatsu R5509-72 NIR photomultiplier tube detector whose detectivity drops at 1620 nm. Due to high active P concentration, we expect band gap narrowing phenomena to push the PL peak to wavelengths beyond the detection limit

  1. Doped Titanium Dioxide Films Prepared by Pulsed Laser Deposition Method

    Directory of Open Access Journals (Sweden)

    Juguang Hu

    2012-01-01

    Full Text Available TiO2 was intensively researched especially for photocatalystic applications. The nitrogen-doped TiO2 films prepared by pulsed laser deposition (PLD method were reviewed, and some recent new experimental results were also presented in this paper. A new optical transmission method for evaluating the photocatalystic activity was presented. The main results are (1 PLD method is versatile for preparing oxide material or complex component films with excellent controllability and high reproducibility. (2 Anatase nitrogen-doped TiO2 films were prepared at room temperature, 200°C, and 400°C by PLD method using novel ceramic target of mixture of TiN and TiO2. UV/Vis spectra, AFM, Raman spectra, and photocatalystic activity for decomposition of methyl orange (MO tests showed that visible light response was improved at higher temperature. (3 The automatic, continuous optical transmission autorecorder method is suitable for detecting the photodecomposition dynamic process of organic compound.

  2. 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....

  3. Advances in Laser Cooling of Thulium-Doped Glass

    Science.gov (United States)

    2003-05-01

    conversion,’’ Appl. Phys. Lett. 75, 1258–1260 (1999). 21. L. Wetenkamp, G. F. West, and H. Tobben, ‘‘Optical proper- ties of rare earth-doped ZBLAN glasses ...properties of Tm31 in ZBLAN fluoride glass . Part 2. Judd-Ofelt parameters,’’ Phys. Chem. Glasses 36, 139–140 (1995). 38. M. J. Weber, ‘‘Laser excited...Advances in laser cooling of thulium-doped glass C. W. Hoyt, M. P. Hasselbeck, and M. Sheik-Bahae Department of Physics and Astronomy, University of

  4. Generating 2 micron continuous-wave ytterbium-doped fiber laser-based optical parametric effect

    Science.gov (United States)

    Paul, M. C.; Latiff, A. A.; Hisyam, M. B.; Rusdi, M. F. M.; Harun, S. W.

    2016-10-01

    We report an efficient method for generating a 2 micron laser based on an optical parametric oscillator (OPO). It uses a long piece of a newly developed double-clad ytterbium-doped fiber (YDF), which is obtained by doping multi-elements of ZrO2, CeO2 and CaO in a phospho-alumina-silica glass as a gain medium. The efficient 2 micron laser generation is successful due to the presence of partially crystalline Yb-doped ZrO2 nano-particles that serve as a nonlinear material in a linear cavity configuration and high watt-level pump power. Stable self-wavelength double lasing at 2122 nm with an efficiency of 7.15% is successfully recorded. At a maximum pump power of 4.1 W, the output power is about 201 mW.

  5. Laser-induced down-conversion parameters of singly and doubly doped ZnS phosphors

    Indian Academy of Sciences (India)

    H S Bhatti; Rajesh Sharma; N K Verma

    2005-09-01

    Singly and doubly doped ZnS phosphors have been synthesized using flux method. Laser-induced photoluminescence has been observed in ZnS-doped phosphors when these were excited by the pulsed UV N2 laser radiation. Due to down-conversion phenomenon, fast phosphorescence emission in the visible region is recorded in milliseconds time domain for ZnS:Mn while in the case of ZnS:Mn:killer (Fe, Co and Ni) the lifetime reduces to microseconds time domain. Experimentally observed luminescent emission parameters of excited states such as, lifetimes, trap-depth values and decay constants have been reported here at room temperature. The high efficiency and fast recombination times observed in doped ZnS phosphors make these materials very attractive for optoelectronic applications.

  6. Extracting physical properties of arbitrarily shaped laser-doped micro-scale areas in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, Martin, E-mail: mh@nus.edu.sg [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore, Singapore 117574 (Singapore); NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore, Singapore 117456 (Singapore); Kluska, Sven [Fraunhofer Institute for Solar Energy Systems (ISE), Heidenhofstr. 2, D-79110 Freiburg (Germany); Hameiri, Ziv; Hoex, Bram [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore, Singapore 117574 (Singapore); Aberle, Armin G. [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore, Singapore 117574 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore 117456 (Singapore)

    2013-12-23

    We present a method that allows the extraction of relevant physical properties such as sheet resistance and dopant profile from arbitrarily shaped laser-doped micro-scale areas formed in semiconductors with a focused pulsed laser beam. The key feature of the method is to use large laser-doped areas with an identical average number of laser pulses per area (laser pulse density) as the arbitrarily shaped areas. The method is verified using sheet resistance measurements on laser-doped silicon samples. Furthermore, the method is extended to doping with continuous-wave lasers by using the average number of passes per area or density of passes.

  7. The influence of oxygen partial pressure on material properties of Eu{sup 3+}-doped Y{sub 2}O{sub 2}S thin film deposited by Pulsed Laser Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ali, A.G., E-mail: aliag@qwa.ufs.ac.za [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Dejene, B.F. [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Swart, H.C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300 (South Africa)

    2016-01-01

    Eu{sup 3+}-doping has been of interest to improve the luminescent characteristics of thin-film phosphors. Y{sub 2}O{sub 2}S:Eu{sup 3+} films have been grown on Si (100) substrates by using a Pulsed Laser Deposition technique. The thin films grown under different oxygen deposition pressure conditions have been characterized using structural and luminescent measurements. The X-ray diffraction patterns showed mixed phases of cubic and hexagonal crystal structures. As the oxygen partial pressure increased, the crystallinity of the films improved. Further increase of the O{sub 2} pressure to 140 mtorr reduced the crystallinity of the film. Similarly, both scanning electron microscopy and Atomic Force Microscopy confirmed that an increase in O{sub 2} pressure affected the morphology of the films. The average band gap of the films calculated from diffuse reflectance spectra using the Kubelka–Munk function was about 4.75 eV. The photoluminescence measurements indicated red emission of Y{sub 2}O{sub 2}S:Eu{sup 3+} thin films with the most intense peak appearing at 619 nm, which is assigned to the {sup 5}D{sub 0}–{sup 7}F{sub 2} transition of Eu{sup 3+}. This most intense peak was totally quenched at higher O{sub 2} pressures. This phosphor may be a promising material for applications in the flat panel displays.

  8. Possibilities of Laser Processing of Paper Materials

    Science.gov (United States)

    Stepanov, Alexander; Saukkonen, Esa; Piili, Heidi

    Nowadays, lasers are applied in many industrial processes: the most developed technologies include such processes as laser welding, hybrid welding, laser cutting of steel, etc. In addition to laser processing of metallic materials, there are also many industrial applications of laser processing of non-metallic materials, like laser welding of polymers, laser marking of glass and laser cutting of wood-based materials. It is commonly known that laser beam is suitable for cutting of paper materials as well as all natural wood-fiber based materials. This study reveals the potential and gives overview of laser application in processing of paper materials. In 1990's laser technology increased its volume in papermaking industry; lasers at paper industry gained acceptance for different perforating and scoring applications. Nowadays, with reduction in the cost of equipment and development of laser technology (especially development of CO2 technology), laser processing of paper material has started to become more widely used and more efficient. However, there exists quite little published research results and reviews about laser processing of paper materials. In addition, forest industry products with pulp and paper products in particular are among major contributors for the Finnish economy with 20% share of total exports in the year 2013. This has been the standpoint of view and motivation for writing this literature review article: when there exists more published research work, knowledge of laser technology can be increased to apply it for processing of paper materials.

  9. Millisecond laser machining of transparent materials assisted by nanosecond laser.

    Science.gov (United States)

    Pan, Yunxiang; Zhang, Hongchao; Chen, Jun; Han, Bing; Shen, Zhonghua; Lu, Jian; Ni, Xiaowu

    2015-01-26

    A new form of double pulse composed of a nanosecond laser and a millisecond laser is proposed for laser machining transparent materials. To evaluate its advantages and disadvantages, experimental investigations are carried out and the corresponding results are compared with those of single millisecond laser. The mechanism is discussed from two aspects: material defects and effects of modifications induced by nanosecond laser on thermal stress field during millisecond laser irradiation. It is shown that the modifications of the sample generated by nanosecond laser improves the processing efficiency of subsequent millisecond laser, while limits the eventual size of modified region.

  10. Excimer laser doping technique for application in an integrated CdTe imaging device

    CERN Document Server

    Mochizuki, D; Aoki, T; Tomita, Y; Nihashi, T; Hatanaka, Y

    1999-01-01

    CdTe is an attractive semiconductor material for applications in solid-state high-energy X-ray and gamma-ray imaging systems because of its high absorption coefficient, large band gap, good mobility lifetime product of holes and stability at normal atmospheric conditions. We propose a new concept for fabricating an integrated CdTe with monolithic circuit configuration for two-dimensional imaging systems suitable for medical, research or industrial applications and operation at room temperature. A new doping technique has been recently developed that employs excimer laser radiation to diffuse impurity atoms into the semiconductor. Accordingly, heavily doped n- and p-type layers with resistivities less than 1 OMEGA cm can be formed on the high resistive CdTe crystals. We have further extended this technique for doping with spatial pattern. We will present the laser doping technique and various results thus obtained. Spatially patterned doping is demonstrated and we propose the use of these doping techniques for...

  11. High-power thulium-doped fiber laser in an all-fiber configuration

    Science.gov (United States)

    Baravets, Yauhen; Todorov, Filip; Honzatko, Pavel

    2016-12-01

    High-power Tm-doped fiber lasers are greatly suitable for various applications, such as material processing, medicine, environmental monitoring and topography. In this work we present an all-fiber narrowband CW laser in near fundamental mode operation based on a Tm-doped double-clad active fiber pumped by 793 nm laser diodes with a central wavelength stabilized at 2039 nm by a fiber Bragg grating. The achieved output power is 60 W with a slope efficiency of 46%. The measured beam quality factor is less than 1.4. Further increasing of the output power is possible using various power scaling techniques, for example, coherent combination of several Tm-doped fiber lasers. The developed fiber laser could be employed for welding, cutting and marking of thermoplastics in industry, minimally invasive surgery in medicine or sensors in lidar systems. Future improvements of thulium fiber lasers are possible due to the extremely wide gain-bandwidth of the active medium and the rapid growth of 2-μm fiber components production.

  12. Materials for high average power lasers

    Energy Technology Data Exchange (ETDEWEB)

    Marion, J.E.; Pertica, A.J.

    1989-01-01

    Unique materials properties requirements for solid state high average power (HAP) lasers dictate a materials development research program. A review of the desirable laser, optical and thermo-mechanical properties for HAP lasers precedes an assessment of the development status for crystalline and glass hosts optimized for HAP lasers. 24 refs., 7 figs., 1 tab.

  13. NEW ERBIUM DOPED ANTIMONY GLASSES FOR LASER AND GLASS AMPLIFICATION

    Directory of Open Access Journals (Sweden)

    B. Tioua

    2015-07-01

    Full Text Available Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses. In this poster will offer new doped erbium glasses synthesized in silicate crucibles were obtained in the combination Sb2O3-WO3-Na2O. Several properties are measured and correlated with glass compositions. The absorption spectral studies have been performed for erbium doped glasses. The intensities of various absorption bands of the doped glasses are measured and the Judd-Ofelt parameters have been computed. From the theory of Judd-Ofelt, various radiative properties, such as transition probability, branching ratio and radiative life time for various emission levels of these doped glasses have been determined and reported. These results confirm the ability of antimony glasses for glass amplification.

  14. NEW ERBIUM DOPED ANTIMONY GLASSES FOR LASER AND GLASS AMPLIFICATIONmplification

    Directory of Open Access Journals (Sweden)

    B. Tioua

    2012-06-01

    Full Text Available Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses. in this poster will offer new doped erbium glasses synthesized in silicate crucibles were obtained in the combination Sb2O3-WO3-Na2O. Several properties are measured and correlated with glass compositions. The absorption spectral studies have been performed for erbium doped glasses. The intensities of various absorption bands of the doped glasses are measured and the Judd-Ofelt parameters have been computed. From the theory of Judd-Ofelt, various radiative properties, such as transition probability, branching ratio and radiative life time for various emission levels of these doped glasses have been determined and reported. These results confirm the ability of antimony glasses for glass amplification.

  15. Fluorescence Properties of Fe2+- and Co2+-doped Hosts of CdMnTe Compositions as Potential Mid-Infrared Laser Materials

    Science.gov (United States)

    2011-09-01

    laser 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 22 19a. NAME OF RESPONSIBLE...are melt growth, physical vapor transport ( PVD ), and chemical vapor 3 transport (CVD). The melt growth technique is the preferred method of growing...parametric oscillator PVD physical vapor deposition RT room temperature Ti titanium TM transitional metal YAG yttrium aluminum garnet YLF

  16. Coherent combining in an Yb doped double core fiber laser

    CERN Document Server

    Boullet, Johan; Desfarges-Berthelemot, Agnès; Kermène, Vincent; Pagnoux, Dominique; Roy, Philippe; Dussardier, Bernard; Blanc, Wilfried; 10.1364/OL.30.001962

    2012-01-01

    Coherent combining is demonstrated in a clad pumped Yb doped double core fiber laser. A slope efficiency of more than 70 % is achieved with 96 % of the total output power on the fundamental mode of one of the two cores. This high combining efficiency is obtained when both cores are coupled via a biconical fused taper in a Michelson interferometer configuration.

  17. Controlling hyperchaos in erbium-doped fibre laser

    Institute of Scientific and Technical Information of China (English)

    张胜海; 沈柯

    2003-01-01

    The dual-ring erbium-doped fibre laser shows a hyperchaotic behaviour under some conditions. The hyperchaotic behaviour can be well controlled to enter into periodicity by modulating the pumping in one of the two rings. The period is different for different modulation index at the same modulation frequency, or for different modulation frequency at the same modulation index.

  18. 152 fs nanotube-mode-locked thulium-doped all-fiber laser

    Science.gov (United States)

    Wang, Jinzhang; Liang, Xiaoyan; Hu, Guohua; Zheng, Zhijian; Lin, Shenghua; Ouyang, Deqin; Wu, Xu; Yan, Peiguang; Ruan, Shuangchen; Sun, Zhipei; Hasan, Tawfique

    2016-07-01

    Ultrafast fiber lasers with broad bandwidth and short pulse duration have a variety of applications, such as ultrafast time-resolved spectroscopy and supercontinuum generation. We report a simple and compact all-fiber thulium-doped femtosecond laser mode-locked by carbon nanotubes. The oscillator operates in slightly normal cavity dispersion at 0.055 ps2, and delivers 152 fs pulses with 52.8 nm bandwidth and 0.19 nJ pulse energy. This is the shortest pulse duration and the widest spectral width demonstrated from Tm-doped all-fiber lasers based on 1 or 2 dimensional nanomaterials, underscoring their growing potential as versatile saturable absorber materials.

  19. Direct laser interference patterning of polystyrene films doped with azo dyes, using 355 nm laser light

    Energy Technology Data Exchange (ETDEWEB)

    Broglia, M.F. [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina); Saarland University, Department of Materials Science, Campus, D-66123 Saarbrücken (Germany); Suarez, S.; Soldera, F.; Mücklich, F. [Saarland University, Department of Materials Science, Campus, D-66123 Saarbrücken (Germany); Barbero, C.A.; Bellingeri, R.; Alustiza, F. [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina); Acevedo, D., E-mail: dacevedo@exa.unrc.edu.ar [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina)

    2014-05-01

    Highlights: • We describe the first use of Direct Laser Interference Patterning on PS at 355 nm. . • The structured areas of regular lines are produced in several square millimeters. • The method, Direct Laser Interference Patterning (DLIP) uses a single laser pulse. • DLIP is applied at room temperature and atmospheric pressure. • DLIP is easier to use than other lithographic techniques. • The topography contrasts with the usual Polystyrene ablation at lower wavelengths. - Abstract: The generation of line-like periodic patterns by direct laser interference patterning (DLIP) of polystyrene films (PS) at a wavelength of 355 nm has been investigated. No structuration is achieved in plain PS due to the weak absorption of the polymer at 355 nm. On the other hand, patterning is achieved on films doped (PSd) with an azo dye (2-anisidine → 2-anisidine) which is incorporated in the polymer solution used for film preparation. Periodic micro-structures are generated. DLIP on PSd results in the swelling of the surface at low fluences, while at high laser intensities it causes the ablation of the regions at the interference maxima positions. The results contrast with the usual process of DLIP on PS (at shorter wavelengths, like 266 nm) where only ablation is detected. The results suggest that decomposition of the azo dye is the driving force of the patterning which therefore differ from the patterning obtained when plain PS is irradiated with laser light able to be absorbed by the aromatic ring in PS (e.g. 266 nm). The biocompatibility of these materials and adhesion of cells was tested, the data from in vitro assays shows that fibroblast cells are attached and proliferate extensively on the PSd films.

  20. Laser And Nonlinear Optical Materials For Laser Remote Sensing

    Science.gov (United States)

    Barnes, Norman P.

    2005-01-01

    NASA remote sensing missions involving laser systems and their economic impact are outlined. Potential remote sensing missions include: green house gasses, tropospheric winds, ozone, water vapor, and ice cap thickness. Systems to perform these measurements use lanthanide series lasers and nonlinear devices including second harmonic generators and parametric oscillators. Demands these missions place on the laser and nonlinear optical materials are discussed from a materials point of view. Methods of designing new laser and nonlinear optical materials to meet these demands are presented.

  1. Single mode dye-doped polymer photonic crystal lasers

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Buss, Thomas; Smith, Cameron

    2010-01-01

    Dye-doped polymer photonic crystal (PhC) lasers fabricated by combined nanoimprint and photolithography are studied for their reproducibility and stability characteristics. We introduce a phase shift in the PhC lattice that substantially improves the yield of single wavelength emission. Single mode...... emission and reproducibility of laser characteristics are important if the lasers are to be mass produced in, e. g., optofluidic sensor chips. The fabrication yield is above 85% with highly reproducible wavelengths (within 0.5%), and the temperature dependence on the wavelength is found to be -0.045 or -0...

  2. Silver nanoprisms/silicone hybrid rubber materials and their optical limiting property to femtosecond laser

    Science.gov (United States)

    Li, Chunfang; Liu, Miao; Jiang, Nengkai; Wang, Chunlei; Lin, Weihong; Li, Dongxiang

    2017-08-01

    Optical limiters against femtosecond laser are essential for eye and sensor protection in optical processing system with femtosecond laser as light source. Anisotropic Ag nanoparticles are expected to develop into optical limiting materials for femtosecond laser pulses. Herein, silver nanoprisms are prepared and coated by silica layer, which are then doped into silicone rubber to obtain hybrid rubber sheets. The silver nanoprisms/silicone hybrid rubber sheets exhibit good optical limiting property to femtosecond laser mainly due to nonlinear optical absorption.

  3. Ultralow-threshold laser and blue shift cooperative luminescence in a Yb3+ doped silica microsphere

    Directory of Open Access Journals (Sweden)

    Yantang Huang

    2014-02-01

    Full Text Available An experimental investigation on ultralow threshold laser and blue shift cooperative luminescence (CL in a Yb3+ doped silica microsphere (YDSM with continuous-wave 976 nm laser diode pumping is reported. The experimental results show that the YDSM emits laser oscillation with ultralow threshold of 2.62 μW, and the laser spectrum is modulated by the microsphere morphology characteristics. In addition, blue emission of YDSM is also observed with the increase of pump power, which is supposed to be generated by CL of excited Yb ion-pairs with the absorption of 976 nm photons and Si-O vibration phonons, and the process is explained with an energy level diagram. This property of the blue shift CL with phonons absorption in the Yb3+doped microcavity makes it attractive for the application of laser cooling based on anti-Stokes fluorescence emission, if the Yb3+doped microcavity made from with low phonon energy host materials.

  4. Holmium-doped ZBLAN fiber lasers at 1.2 μm

    Science.gov (United States)

    Zhu, X.; Zong, J.; Norwood, R. A.; Chavez-Person, A.; Peyghambarian, N.; Prasad, N.

    2012-02-01

    Holmium (Ho3+)-doped ZBLAN glasses have been investigated for the purpose of achieving efficient fiber lasers at 1.2 μm. Because of the long lifetime of the upper laser level and the small phonon energy in Ho3+-doped ZBLAN glasses, strong fluorescence at 1.2 μm that usually cannot be observed in Ho-doped silica glass has been measured. Fluorescence of 1 mol%, 3 mol%, and 6 mol% Ho3+-doped ZBLAN glasses are reported. The effect of cerium and terbium ions on the emission of Ho3+-doped ZBLAN glass has also been studied. Obstacles to achieving an efficient Ho3+-doped ZBLAN laser are analyzed and discussed. In studies of a commercial Ho3+-doped ZBLAN fiber laser, it was found that the 3 μm four-energy-level laser can easily overwhelm the 1.2 μm laser, which is a three-energy-level system having the same upper laser level with the 3 μm laser. In order to effectively suppress the competiting 3 μm transition, advanced Ho3+-doped ZBLAN fiber has been designed and fabricated for 1.2 μm fiber lasers. Fiber lasers at 1.2 μm using the new Ho3+-doped ZBLAN fiber have been developed. Our experiments demonstrate that the new Ho3+-doped ZBLAN fiber is an efficient gain medium for lasers at 1.2 μm.

  5. 47-wavelength flat erbium-doped fiber ring laser with reduced operation power

    Institute of Scientific and Technical Information of China (English)

    Qing Wang; Yan Wang; Xiaoming Liu; Bingkun Zhou

    2005-01-01

    @@ A 47-wavelength flat erbium-doped fiber ring laser over whole C-band is experimentally achieved with only 21-dBm output power from erbium-doped fiber amplifier (EDFA). The spectrum flatness of the multiwavelength erbium-doped fiber laser (EDFL) is investigated.

  6. Direct laser interference patterning of polystyrene films doped with azo dyes, using 355 nm laser light

    Science.gov (United States)

    Broglia, M. F.; Suarez, S.; Soldera, F.; Mücklich, F.; Barbero, C. A.; Bellingeri, R.; Alustiza, F.; Acevedo, D.

    2014-05-01

    The generation of line-like periodic patterns by direct laser interference patterning (DLIP) of polystyrene films (PS) at a wavelength of 355 nm has been investigated. No structuration is achieved in plain PS due to the weak absorption of the polymer at 355 nm. On the other hand, patterning is achieved on films doped (PSd) with an azo dye (2-anisidine → 2-anisidine) which is incorporated in the polymer solution used for film preparation. Periodic micro-structures are generated. DLIP on PSd results in the swelling of the surface at low fluences, while at high laser intensities it causes the ablation of the regions at the interference maxima positions. The results contrast with the usual process of DLIP on PS (at shorter wavelengths, like 266 nm) where only ablation is detected. The results suggest that decomposition of the azo dye is the driving force of the patterning which therefore differ from the patterning obtained when plain PS is irradiated with laser light able to be absorbed by the aromatic ring in PS (e.g. 266 nm). The biocompatibility of these materials and adhesion of cells was tested, the data from in vitro assays shows that fibroblast cells are attached and proliferate extensively on the PSd films.

  7. Synchronization of chaotic oscillations in doped fiber ring lasers

    CERN Document Server

    Lewis, C T; Kennel, M B; Buhl, M; Illing, L; Lewis, Clifford Tureman; Abarbanel, Henry D I; Kennel, Matthew B; Buhl, Michael; Illing, Lucas

    1999-01-01

    We investigate synchronization and subsequently communication using chaotic rare-earth-doped fiber ring lasers, represented by a physically realistic model. The lasers are coupled by transmitting a fraction c of the circulating electric field in the transmitter and injecting it into the optical cavity of the receiver. We then analyze a coupling strategy which relies on modulation of the intensity of the light alone. This avoids problems associated with the polarization and phase of the laser light. We study synchronization as a function of the coupling strength and see excellent convergence, even with small coupling constants. We prove that in an open-loop configuration (c=1) synchronization is guaranteed due to the particular structure of our equations and of the injection method we use for these coupled laser systems. We also analyze the generalized synchronization of these model lasers when there is parameter mismatch between the transmitter and the receiver. We then address communicating information betwe...

  8. Pure and Sn-doped ZnO films produced by pulsed laser deposition

    DEFF Research Database (Denmark)

    Holmelund, E.; Schou, Jørgen; Tougaard, S.;

    2002-01-01

    A new technique, metronome doping, has been used for doping of films during pulsed laser deposition (PLD). This technique makes it possible to dope continuously during film growth with different concentrations of a dopant in one deposition sequence. Films of pure and doped ZnO have been produced...

  9. Measurement of product of solid state laser materials by an alternative method: Application to Nd3+ doped YVO4 crystal for $^{4}F_{3/2}→ {}^{4}I_{11/2}$ transition

    Indian Academy of Sciences (India)

    P K Mukhopadhyay; Jogy George; S K Sharma; Rakesh Kapoor; T P S Nathan

    2001-01-01

    In this paper an alternative approach for measurement of product for $^{4}F_{3/2}→ {}^{4}I_{11/2}$ transition of Nd3+ doped YVO4 crystal is reported. In this method a microchip laser is formed by keeping a small piece of the sample in plane–plane resonator and a diode laser (808 nm) is used for pumping. The pump power induced thermal lensing effect is used to make the cavity stable. The cavity mode area is estimated by measuring the thermal lens focal length at the threshold and the average pump area is measured by Gaussian fit to the intensity profiles of the pump beam. The value of product of Nd:YVO4 crystal obtained by this method is within 10% of the reported values. The advantage of this method is that it is a simple method for direct measurement of product of laser crystals.

  10. Hybrid Neodymium-doped passively Q-switched waveguide laser

    Energy Technology Data Exchange (ETDEWEB)

    Salas-Montiel, Rafael [IMEP-LAHC, 3 Parvis Louis Neel BP 257, 38016 Grenoble Cedex 1 (France); Bastard, Lionel [IMEP-LAHC, 3 Parvis Louis Neel BP 257, 38016 Grenoble Cedex 1 (France)], E-mail: lionel.bastard@minatec.inpg.fr; Grosa, Gregory; Broquin, Jean-Emmanuel [IMEP-LAHC, 3 Parvis Louis Neel BP 257, 38016 Grenoble Cedex 1 (France)

    2008-03-25

    In the mid 80s, the doping of optical fibers' core with rare earth atoms has been a major breakthrough in the field of optical telecommunications since it allowed the realization of in line optical amplifiers. However, erbium-doped fiber amplifiers are a few meters long and a huge effort has been made in order to realize compact and efficient active devices based on rare-earth-doped waveguides. For this purpose the use of phosphate glasses instead of silicate ones has been investigated because they allow a better solubility of the inserted rare earths. In this paper we present the realization of a hybrid Neodymium-doped passively Q-switched waveguide laser made by an ion-exchange on a Schott IOG-1 phosphate laser glass combined with the deposition of a bis(4-dimethylaminodithiobenzil)nickel (BDN) saturable absorber diluted in a cellulose acetate polymer cladding. In a first step, we present the continuous wave (CW) operation of the laser with an undoped cladding. We show that for a 3.5 {mu}m wide, 1.5 cm long waveguide realized by a silver-sodium ion-exchange, a 6 mW output has been achieved by creating a Fabry-Perot cavity with dielectric multilayers mirrors sticked to the chip facets. Then, the characterizations performed on the BDN-doped layers are presented. It is shown that a proper selection of the hybrid guiding condition and saturable absorber concentration entail a non-saturated excess absorption of 3.4 dB/cm. Finally, we present the results we obtained on the Q-switched behaviour of the laser. Indeed a repetition rate of 330 kHz is achieved for a pulse energy of 10 nJ and a peak power of 1 W.

  11. Erbium doped random fiber laser and fiber mixing effect

    OpenAIRE

    Yao, Can; Thévenaz, Luc; Brès, Camille Sophie

    2017-01-01

    We demonstrate an active random fiber laser by directly pumping a 100 m erbium-doped fiber at 980 nm wavelength, with a fiber loop mirror forming a half-open cavity. Random lasing with competing spectral modes in the range from 1535 nm to 1560 nm is achieved, with the maximum lasing slope efficiency around 10%. We also study the effect of combining a dispersion compensated fiber with the erbium-doped fiber. The kilometers long dispersion compensated fiber reduces the random lasing threshold a...

  12. Laser-assisted fabrication of materials

    CERN Document Server

    Manna, Indranil

    2013-01-01

    Laser assisted fabrication involves shaping of materials using laser as a source of heat. It can be achieved by removal of materials (laser assisted cutting, drilling, etc.), deformation (bending, extrusion), joining (welding, soldering) and addition of materials (surface cladding or direct laser cladding). This book on ´Laser assisted Fabrication’ is aimed at developing in-depth engineering concepts on various laser assisted macro and micro-fabrication techniques with the focus on application and a review of the engineering background of different micro/macro-fabrication techniques, thermal history of the treated zone and microstructural development and evolution of properties of the treated zone.

  13. 2.05 µm holmium-doped all-fiber laser diode-pumped at 1.125 µm

    Science.gov (United States)

    Kir'yanov, A. V.; Barmenkov, Y. O.; Villegas Garcia, I.

    2017-08-01

    We report a holmium-doped all-fiber laser oscillating at ~2.05 µm in continuous wave at direct in-core pumping by a 1.125 µm laser diode. Two types of home-made holmium-doped alumino-germano-silicate fiber (HDF), differentiated in the Ho3+ doping level, were fabricated to implement the laser, for revealing the effect of Ho3+ concentration upon the laser output. Firstly, the fibers were characterized thoroughly from the material and optical viewpoints. Then, laser action with both HDFs was assessed using the simplest Fabry-Perot cavity, assembled by a couple of spectrally adjusted fiber Bragg gratings, also made-in-house. In the best case, when using the lower-doped HDF of proper length (1.4 m), low threshold (~370 mW) and moderate slope efficiency (~13%) of ~2.05 µm lasing were obtained at 1.125 µm diode pumping. Long-term stability, high brightness, low noise, and purely CW operation are shown to be the laser’s attractive features. Yet, when utilizing the heavier-doped HDF, laser output is revealed to be overall worse, with a possible reason being the deteriorating Ho3+ concentration-related effects.

  14. Q-Switched Thulium-Doped Domestic Silica Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    HU Hui; DU Ge-Guo; YAN Pei-Guang; ZHAO Jun-Qing; GUO Chun-Yu; RUAN Shuang-Chen

    2011-01-01

    We report a cladding-pumped Tm3+-doped domestic silica fiber laser operated at 2μm and actively Q-switched with an acousto-optic modulator. Pulse trains are obtained as pumped by a 785nm laser diode. The maximum average output power is 1.27 W. Peak power up to 4.2 kW and pulse energy up to 840 μJ are obtained with the pulse duration of 200ns produced at a repetition rate of 1 kHz. The laser performance is studied under different repetition rates and pump powers. Lastly, we give some discussion.%@@ We report a cladding-pumped Tm3+-doped domestic silica fiber laser operated at 2pm and actively Q-switched with an acousto-optic modulator.Pulse trains are obtained as pumped by a 785nm laser diode.The maximum average output power is 1.27W.Peak power up to 4.2kW and pulse energy up to 840μJ are obtained with the pulse duration of 200ns produced at a repetition rate of 1 kHz.The laser performance is studied under different repetition rates and pump powers.Lastly, we give some discussion.

  15. Doping of germanium and silicon crystals with non-hydrogenic acceptors for far infrared lasers

    Science.gov (United States)

    Haller, Eugene E.; Brundermann, Erik

    2000-01-01

    A method for doping semiconductors used for far infrared lasers with non-hydrogenic acceptors having binding energies larger than the energy of the laser photons. Doping of germanium or silicon crystals with beryllium, zinc or copper. A far infrared laser comprising germanium crystals doped with double or triple acceptor dopants permitting the doped laser to be tuned continuously from 1 to 4 terahertz and to operate in continuous mode. A method for operating semiconductor hole population inversion lasers with a closed cycle refrigerator.

  16. Modeling of Laser Material Interactions

    Science.gov (United States)

    Garrison, Barbara

    2009-03-01

    Irradiation of a substrate by laser light initiates the complex chemical and physical process of ablation where large amounts of material are removed. Ablation has been successfully used in techniques such as nanolithography and LASIK surgery, however a fundamental understanding of the process is necessary in order to further optimize and develop applications. To accurately describe the ablation phenomenon, a model must take into account the multitude of events which occur when a laser irradiates a target including electronic excitation, bond cleavage, desorption of small molecules, ongoing chemical reactions, propagation of stress waves, and bulk ejection of material. A coarse grained molecular dynamics (MD) protocol with an embedded Monte Carlo (MC) scheme has been developed which effectively addresses each of these events during the simulation. Using the simulation technique, thermal and chemical excitation channels are separately studied with a model polymethyl methacrylate system. The effects of the irradiation parameters and reaction pathways on the process dynamics are investigated. The mechanism of ablation for thermal processes is governed by a critical number of bond breaks following the deposition of energy. For the case where an absorbed photon directly causes a bond scission, ablation occurs following the rapid chemical decomposition of material. The study provides insight into the influence of thermal and chemical processes in polymethyl methacrylate and facilitates greater understanding of the complex nature of polymer ablation.

  17. Tuning Optical Nonlinearity of Laser-Ablation-Synthesized Silicon Nanoparticles via Doping Concentration

    Directory of Open Access Journals (Sweden)

    Lianwei Chen

    2014-01-01

    Full Text Available Silicon nanoparticles at different doping concentrations are investigated for tuning their optical nonlinear performance. The silicon nanoparticles are synthesized from doped silicon wafers by pulsed laser ablation. Their dispersions in water are studied for both nonlinear absorption and nonlinear refraction properties. It is found that the optical nonlinear performance can be modified by the doping concentration. Nanoparticles at a higher doping concentration exhibit better saturable absorption performance for femtosecond laser pulse, which is ascribed to the free carrier absorption mechanism.

  18. Erbium - doped fiber laser systems: Routes to chaos

    Directory of Open Access Journals (Sweden)

    Rubežić Vesna

    2014-01-01

    Full Text Available Erbium-doped fiber laser systems exhibit a large variety of complex dynamical behaviors, bifurcations and attractors. In this paper, the chaotic behavior which can be achieved under certain conditions in a laser system with erbium-doped fiber, is discussed. The chaos in this system occurs through several standard scenarios. In this paper, the simulation sequence of quasiperiodic, intermittent and period-doubling scenario transitions to chaos is shown. Quasiperiodic and intermittent transitions to chaos are shown on the example system with a single ring. The electro-optical modulator was applied to the system for modulating the loss in the cavity. We used the sinusoidal and rectangular signals for modulation. Generation of chaos is achieved by changing the parameters of signal for modulation. Period-doubling transition to chaos is illustrated in a system with two rings. Simulation results are shown in the time domain and phase space.

  19. Hybrid ytterbium doped active medium for femtosecond lasers

    Science.gov (United States)

    Pestryakov, E. V.; Petrov, V. V.; Trunov, V. I.; Kirpichnikov, A. V.; Laptev, A. V.; Merzliakov, M. A.; Bagayev, S. N.; Matrosov, V. N.

    2007-04-01

    Hybrid laser medium on the base of the Yb:YVO4 and Yb:YAG (and Yb:KYW) crystals with overlapping broadband gain contours in common cavity was experimentally analyzed. On the absorption and fluorescence data at liquid helium temperature, excited states lifetimes the energy of electronic levels of ytterbium in vanadate crystalline hosts were calculated and the lasing parameters of broadband transitions of doped ions were studied. It has been shown that, this way of forming of the stationary regime of ultrashort pulses generation with duration in accordance with combined gain bandwidth in the laser with hybrid active medium is perspective.

  20. A 115-W Ytterbium-Doped Fibre Laser

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jun; WANG Zhi-Jiang; LOU Qi-Hong; KONG Ling-Feng; WU Zhong-Lin; XUE Dong; DONG Jing-Xing; WEI Yun-Rong; YE Zhen-Huan; ZHU Jian-Qiang

    2004-01-01

    @@ We report a highly efficient ytterbium-doped double-clad fibre laser, one-end pumped by a 975-nm diode stack source and generating up to 115.6 W of cw output power at 1.1 μm. The maximum optical-to-optical conversion efficiency with respect to the launched pump power is 79% at 65-W output power, and the overall slope efficiency is about 69%.

  1. Erbium-doped fiber lasers as deep-sea hydrophones

    Energy Technology Data Exchange (ETDEWEB)

    Bagnoli, P.E. [Dipartimento di Ingegneria dell' Informazione University of Pisa, Via Diotisalvi, Pisa 56100 (Italy); Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, Pisa 56127 (Italy); Beverini, N. [Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, Pisa 56127 (Italy); Dipartimento di Fisica ' E.Fermi' University of Pisa, Largo Pontecorvo 3, 56127 (Italy); Bouhadef, B. [Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, Pisa 56127 (Italy); Dipartimento di Fisica ' E.Fermi' University of Pisa, Largo Pontecorvo 3, 56127 (Italy); Castorina, E. [Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, Pisa 56127 (Italy); Dipartimento di Fisica ' E.Fermi' University of Pisa, Largo Pontecorvo 3, 56127 (Italy); Falchini, E. [Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, Pisa 56127 (Italy); Dipartimento di Fisica ' E.Fermi' University of Pisa, Largo Pontecorvo 3, 56127 (Italy); Falciai, R. [Istituto di Fisica Applicata ' Nello Carrara' , IFAC-CNR, Florence (Italy); Flaminio, V. [Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, Pisa 56127 (Italy); Dipartimento di Fisica ' E.Fermi' University of Pisa, Largo Pontecorvo 3, 56127 (Italy); Maccioni, E. [Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, Pisa 56127 (Italy) and Dipartimento di Fisica ' E.Fermi' University of Pisa, Largo Pontecorvo 3, 56127 (Italy)]. E-mail: maccioni@df.unipi.it; Morganti, M. [Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, Pisa 56127 (Italy); Dipartimento di Fisica ' E.Fermi' University of Pisa, Largo Pontecorvo 3, 56127 (Italy); Sorrentino, F. [Dipartimento di Fisica ' E.Fermi' University of Pisa, Largo Pontecorvo 3, 56127 (Italy); Stefani, F. [Dipartimento di Ingegneria dell' Informazione University of Pisa, Via Diotisalvi, Pisa 56100 (Italy); Trono, C. [Dipartimento di Fisica ' E.Fermi' University of Pisa, Largo Pontecorvo 3, 56127 (Italy); Istituto di Fisica Applicata ' Nello Carrara' , IFAC-CNR, Florence (Italy)

    2006-11-15

    The present work describes the development of a hydrophone prototype for deep-sea acoustic detection. The base-sensitive element is a single-mode erbium-doped fiber laser. The high sensitivity of these sensors makes them particularly suitable for a wide range of deep-sea acoustic applications, including geological and marine mammals surveys and above all as acoustic detectors in under-water telescopes for high-energy neutrinos.

  2. Effect of uniaxial stress on gallium, beryllium, and copper-doped germanium hole population inversion lasers

    Energy Technology Data Exchange (ETDEWEB)

    Chamberlin, Danielle Russell [Univ. of California, Berkeley, CA (United States)

    1998-05-01

    The effects of stress on germanium lasers doped with single, double, and triple acceptors have been investigated. The results can be explained quantitatively with theoretical calculations and can be attributed to specific changes in the energy levels of acceptors in germanium under stress. In contrast to previous measurements, gallium-doped Ge crystals show a decrease in lasing upon uniaxial stress. The decrease seen here is attributed to the decrease in heavy hole effective mass upon application of uniaxial stress, which results in a decreased population inversion. The discrepancy between this work and previous studies can be explained with the low compensation level of the material used here. Because the amount of ionized impurity scattering in low-compensated germanium lasers is small to begin with, the reduction in scattering with uniaxial stress does not play a significant role in changing the laser operation. Beryllium-doped germanium lasers operate based on a different mechanism of population inversion. In this material it is proposed that holes can transfer between bands by giving their energy to a neutral beryllium atom, raising the hole from the ground to a bound excited state. The free hole will then return to zero energy with some probability of entering the other band. The minimum and maximum E/B ratios for lasing change with uniaxial stress because of the change in effective mass and bound excited state energy. These limits have been calculated for the case of 300 bar [100] stress, and match very well with the observed data. This adds further credence to the proposed mechanism for population inversion in this material. In contrast to Be and Ga-doped lasers, copper-doped lasers under uniaxial stress show an increase in the range of E and B where lasing is seen. To understand this change the theoretical limits for population inversion based on both the optical phonon mechanism and the neutral acceptor mechanism have been calculated. The data are

  3. Rare-earth-ion-doped waveguide lasers on a silicon chip

    Science.gov (United States)

    Pollnau, Markus

    2015-03-01

    Rare-earth-ion-doped materials are of high interest as amplifiers and lasers in integrated optics. Their longer excited-state lifetimes and the weaker refractive-index change accompanied with rare-earth-ion excitation compared to electron-hole pairs in III-V semiconductors provide spatially and temporally stable optical gain, allowing for high-speed amplification and narrow-linewidth lasers. Amorphous Al2O3 deposited onto thermally oxidized silicon wafers offers the advantage of integration with silicon photonics and electronics. Layer deposition by RF reactive co-sputtering and micro-structuring by chlorine-based reactive-ion etching provide low-loss channel waveguides. With erbium doping, we improved the gain to 2 dB/cm at 1533 nm and a gain bandwidth of 80 nm. The gain is limited by migration-accelerated energy-transfer upconversion and a fast quenching process. Since stimulated emission is even faster than this quenching process, lasers are only affected in terms of their threshold, allowing us to demonstrate diode-pumped micro-ring, distributed-feedback (DFB), and distributed-Bragg-reflector (DBR) lasers in Al2O3:Er3+ and Al2O3:Yb3+ on a silicon chip. Surface-relief Bragg gratings were patterned by laser-interference lithography. Monolithic DFB and DBR cavities with Q-factors of 1.35×106 were realized. In an Er-doped DFB laser, single-longitudinal-mode operation at 1545 nm was achieved with a linewidth of 1.7 kHz, corresponding to a laser Q-factor of 1.14×1011. Yb-doped DFB and DBR lasers were demonstrated at 1020 nm with output powers of 55 mW and a slope efficiency of 67% versus launched pump power. A dual-phaseshift, dual-wavelength laser was achieved and a stable microwave signal at ~15 GHz was created via the heterodyne photo-detection of the two laser wavelengths.

  4. Spectroscopic characterization of iron-doped II-VI compounds for laser applications

    Science.gov (United States)

    Martinez, Alan

    The middle Infrared (mid-IR) region of the electromagnetic spectrum between 2 and 15 ?m has many features which are of interest to a variety of fields such as molecular spectroscopy, biomedical applications, industrial process control, oil prospecting, free-space communication and defense-related applications. Because of this, there is a demand for broadly tunable, laser sources operating over this spectral region which can be easily and inexpensively produced. II-VI semiconductor materials doped with transition metals (TM) such as Co 2+, Cr2+, or Fe2+ exhibit highly favorable spectroscopic characteristics for mid-IR laser applications. Among these TM dopants, Fe2+ has absorption and emission which extend the farthest into the longer wavelength portion of the mid-IR. Fe2+:II-VI crystals have been utilized as gain elements in laser systems broadly tunable over the 3-5.5 microm range [1] and as saturable absorbers to Q -switch [2] and mode-lock [3] laser cavities operating over the 2.7-3 microm. TM:II-VI laser gain elements can be fabricated inexpensively by means of post-growth thermal diffusion with large homogeneous dopant concentration and good optical quality[4,5]. The work outlined in this dissertation will focus on the spectroscopic characterization of TM-doped II-VI semiconductors. This work can be categorized into three major thrusts: 1) the development of novel laser materials, 2) improving and extending applications of TM:II-VI crystals as saturable absorbers, and 3) fabrication of laser active bulk crystals. Because current laser sources based on TM:II-VI materials do not cover the entire mid-IR spectral region, it is necessary to explore novel laser sources to extend available emissions toward longer wavelengths. The first objective of this dissertation is the spectroscopic characterization of novel ternary host crystals doped with Fe2+ ions. Using crystal field engineering, laser materials can be prepared with emissions placed in spectral regions not

  5. Study on Thermal Stability and Spectroscopic Properties of Nd3+ -Doped Phosphate Laser Glasses

    Institute of Scientific and Technical Information of China (English)

    Shi Qi; Lv Jingwen; Cheng Hong; Fu Xingguo; Sun Yu

    2004-01-01

    Fluorescence spectra, absorption spectra and thermal stability properties of Nd3 + -doped phosphate laser glasses were tested in this work. We calculated spectroscopic parameters of Nd3 + -doped phosphate laser glasses according to their absorption spectrum. Measuring and calculating linear thermal expansion coefficient, and analysising thermal stability of glasses show that this kind of Nd3 + -doped phosphate laser glasses has thermal expansion coefficient α = 38.75× 10 -7/℃ and optimal spectroscopic properties which extend application range of Nd +3-doped phosphate laser glasses.

  6. Optical, laser spectroscopic, and electrical characterization of transion metal doped zinc selenide and zinc sulfide nano-and-microcrystals

    Science.gov (United States)

    Kim, Changsu

    Middle-infrared lasers operating over a "molecular fingerprint" 2-15 mum spectral range are in great demand for a variety of applications. One of the best choices for lasing in the 2-5 mum spectral range is direct oscillation from divalent transition metal ions (TM2+: Cr 2+, Fe2+, Co2+)-doped wide bandgap II-VI semiconductor crystals. There are three major objectives in this dissertation: (1) Realize and study middle-infrared electroluminescence of n and p-type, Cr doped bulk ZnSe crystals. We have demonstrated a method of ZnSe crystals thermal-diffusion doping with donor (In, Zn, and Al) and acceptor (Cu, Ag, and N through CrN) impurities resulting in n and p-type conductivity of Cr:ZnSe. We are the first to our knowledge to obtain mid-IR electroluminescence in nominally p-type Cr:Ag:ZnSe, which could prove valuable for developing of novel mid-IR laser diodes. (2) En route to low dimensional gain material, develop simple method for making microscopic laser active Cr doped ZnSe, ZnS and CdSe powders, realize and study their laser spectroscopic characteristics. We have demonstrated a simple physical method of Cr2+:ZnSe, ZnS and CdSe powder fabrication with average sizes below ˜ 10mum and ˜1mum (eliminating stage of bulk crystal growth) and demonstrated first ever mid-IR random lasing on these powders under optical excitation. In addition, we have examine suspensions and polymer films impregnated with Cr:II-VI powders for random lasing in the mid-IR. The powder, suspension and polymer samples are fabricated and characterized through the measurement of photoluminescence (PL) spectra, PL kinetics, and lasing threshold energy. (3) En route to low dimensional gain material, develop method for making laser active Cr, Co, and Fe doped ZnSe and ZnS quantum dots (QD), realize and study their laser spectroscopic characteristics. We have demonstrated a novel method of TM doped II-VI QDs fabrication based on laser ablation in liquid and Ar environment. TM doped II-VI QDs

  7. Rare-earth-doped materials for applications in quantum information storage and signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Thiel, C.W., E-mail: thiel@physics.montana.ed [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Boettger, Thomas, E-mail: tbottger@usfca.ed [Department of Physics and Astronomy, University of San Francisco, 2130 Fulton St., San Francisco, CA 94117 (United States); Cone, R.L., E-mail: cone@montana.ed [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2011-03-15

    Realization of practical quantum memory and optical signal processing systems critically depends on suitable materials that offer specific combinations of properties. Solid-state materials such as rare-earth ions doped into dielectric crystals are one of the most promising candidates for several quantum information storage protocols, including quantum storage of single photons. This article provides an overview of rare-earth-doped material properties and summarizes some of the most promising materials studied in our laboratory and by other groups for applications in quantum information storage and for ultra-wide bandwidth signal processing. Understanding and controlling spectral diffusion in these materials, which ultimately limits the achievable performance of any quantum memory system, is also briefly reviewed. Applications in quantum information impose stringent requirements on laser phase and frequency stability, and employing a narrow spectral hole in the inhomogeneous absorption profile in these materials as a frequency reference can dramatically improve laser stability. We review our work on laser frequency and phase stabilization and report our recent results on using a narrow spectral hole as a passive dynamic spectral filter for laser phase noise suppression, which can dramatically narrow the laser linewidth with or without the requirement of active feedback. - Research highlights: Rare-earth materials offer key properties for quantum memory and signal processing. Physics and properties of rare-earth optical transitions in solids are reviewed. Details of 47 promising optical transitions are tabulated and compared. A new narrow-band dynamic filtering method using spectral hole burning is discussed. Results of successful passive laser phase noise suppression are presented.

  8. Synthesis and Optical Properties of Neodymium-Doped Lanthanum Fluoride Nano-Laser Materials%氟化镧掺钕纳米激光材料的制备及光学性能

    Institute of Scientific and Technical Information of China (English)

    崔晓霞; 高飞; 候超奇; 郭海涛; 王中跃; 韦玮; 彭波

    2013-01-01

    A new type of neodymium-doped lanthanum fluoride (LaF3 ∶ Nd) nanoparticles are synthesized by hydrothermal method.It exhibits hexagonal structure and a size of about 25 nm.A series of different concentrations of LaF3 ∶ Nd nanoparticles dispersion are prepared by ultrasonic technology.The visible-near-infrared spectra show that the dispersion with the optical path of 5 mm and neodymium ion concentration of 1 × 1020 cm-3 shows high transmittance of 85 % at 1053 nm.The lifetime of the La0.95 Nd0.05 F3 nanoparticles dispersion is 200 μs,compared with that of the powder,it is reduced by 3.8%.These results indicate that the LaF3 ∶Nd nanoparticles dispersion with low fluorescence quenching rate,high ion concentration and high transmittance is a kind of promising material used for high repetition rate,high-power and ultra short pulse liquid laser.%利用水热法制备了新型氟化镧掺钕(LaF3∶Nd)纳米材料,其结构为六方晶型,纳米尺寸在25 nm左右;利用超声波分散技术,制备成了一系列具有不同稀土分散浓度的纳米分散液.其钕离子浓度可达到1×1020 cm-3.可见-近红外透射光谱表明,对于5 mm光程的纳米分散液,其在1053 nm处的透射率大于85%,与掺钕透明陶瓷的透射率相当.荧光寿命测试结果显示,该稀土纳米材料(La0.9sNd0.05F3)在分散液中的寿命值为200 μs,与粉末相比,降低了3.8%,表明这种低荧光猝灭率、高离子浓度、高透射率的纳米分散液将是一种可用于高重复率、高功率、超短脉冲的流体激光工作物质.

  9. Laser-induced damage in optical materials

    CERN Document Server

    Ristau, Detlev

    2014-01-01

    Dedicated to users and developers of high-powered systems, Laser-Induced Damage in Optical Materials focuses on the research field of laser-induced damage and explores the significant and steady growth of applications for high-power lasers in the academic, industrial, and military arenas. Written by renowned experts in the field, this book concentrates on the major topics of laser-induced damage in optical materials and most specifically addresses research in laser damage that occurs in the bulk and on the surface or the coating of optical components. It considers key issues in the field of hi

  10. An Sb-doped p-type ZnO nanowire based random laser diode.

    Science.gov (United States)

    Bashar, Sunayna B; Suja, Mohammad; Morshed, Muhammad; Gao, Fan; Liu, Jianlin

    2016-02-12

    An electrically pumped Sb-doped ZnO nanowire/Ga-doped ZnO p-n homojunction random laser is demonstrated. Catalyst-free Sb-doped ZnO nanowires were grown on a Ga-doped ZnO thin film on a Si substrate by chemical vapor deposition. The morphology of the as-grown titled nanowires was observed by scanning electron microscopy. X-ray photoelectron spectroscopy results indicated the incorporation of Sb dopants. Shallow acceptor states of Sb-doped nanowires were confirmed by photoluminescence measurements. Current-voltage measurements of ZnO nanowire structures assembled from p- and n-type materials showed a typical p-n diode characteristic with a threshold voltage of about 7.5 V. Very good photoresponse was observed in the UV region operated at 0 V and different reverse biases. Random lasing behavior with a low-threshold current of around 10 mA was demonstrated at room temperature. The output power was 170 nW at 30 mA.

  11. Structural and Optical Properties of Eu Doped ZnO Nanorods prepared by Pulsed Laser Deposition

    KAUST Repository

    Alarawi, Abeer

    2014-06-23

    Nano structured wide band gap semiconductors have attracted attention of many researchers due to their potential electronic and optoelectronic applications. In this thesis, we report successful synthesis of well aligned Eu doped ZnO nano-rods prepared, for the first time to our knowledge, by pulsed laser deposition (PLD) without any catalyst. X-ray diffraction (XRD) patterns shows that these Eu doped ZnO nanorods are grown along the c-axis of ZnO wurtzite structure. We have studied the effect of the PLD growth conditions on forming vertically aligned Eu doped ZnO nanorods. The structural properties of the material are investigated using a -scanning electron microscope (SEM). The PLD parameters must be carefully controlled in order to obtain c-axis oriented ZnO nanorods on sapphire substrates, without the use of any catalyst. The experiments conducted in order to identify the optimal growth conditions confirmed that, by adjusting the target-substrate distance, substrate temperature, laser energy and deposition duration, the nanorod size could be successfully controlled. Most importantly, the results indicated that the photoluminescence (PL) properties reflect the quality of the ZnO nanorods. These parameters can change the material’s structure from one-dimensional to two-dimensional however the laser energy and frequency affect the size and the height of the nanorods; the xygen pressure changes the density of the nanorods.

  12. Enhanced Laser Cooling of Rare-Earth-Ion-Doped Glass Containing Nanometer-Sized Metallic Particles

    Institute of Scientific and Technical Information of China (English)

    JIA You-Hun; ZHONG Biao; YIN Jian-Ping

    2009-01-01

    The enhanced laser cooling performance of rare-earth-ions-doped glasses containing small particles is predicted. This is achieved by the enhancement of local field around rare earth ions, owing to the surface plasmon resonance of small metallic particles. The role of energy transfer between ions and the particle is theoretical discussed. Depending on the particle size and the ion emission quantum efficiency, the enhancement of the absorption and the fluorescence is predicted. Moreover, taking Yb3+-doped ZBLAN as example, the cooling power and heat-light converting efficiency are calculated. It is finally concluded that the absorption and the fluorescence are greatly enhanced in these composite materials, the cooling power is increased compared to the bulk material.

  13. Progress in the material development of LiCaAlF(6):Cr(3+) laser crystals

    Science.gov (United States)

    Shinn, M. D.; Chase, L. L.; Caird, J. A.; Payne, S. A.; Atherton, L. J.; Kway, W. L.

    1990-03-01

    High Cr(3+) doping levels, up to 8 mole percent, and low losses were obtained with the tunable solid-state laser material LiCaAlF(6):Cr(3+) (Cr:LiCAF). Measurements and calculations show that high pumping and extraction efficiencies are possible with the improved material.

  14. Laser processing and analysis of materials

    CERN Document Server

    Duley, W W

    1983-01-01

    It has often been said that the laser is a solution searching for a problem. The rapid development of laser technology over the past dozen years has led to the availability of reliable, industrially rated laser sources with a wide variety of output characteristics. This, in turn, has resulted in new laser applications as the laser becomes a familiar processing and analytical tool. The field of materials science, in particular, has become a fertile one for new laser applications. Laser annealing, alloying, cladding, and heat treating were all but unknown 10 years ago. Today, each is a separate, dynamic field of research activity with many of the early laboratory experiments resulting in the development of new industrial processing techniques using laser technology. Ten years ago, chemical processing was in its infancy awaiting, primarily, the development of reliable tunable laser sources. Now, with tunability over the entire spectrum from the vacuum ultraviolet to the far infrared, photo­ chemistry is undergo...

  15. Erbium-doped photonic crystal fiber chaotic laser

    Science.gov (United States)

    Martín, Juan C.; Used, Javier; Sánchez-Martín, José A.; Berdejo, Víctor; Vallés, Juan A.; Álvarez, José M.; Rebolledo, Miguel A.

    2011-09-01

    An erbium-doped photonic crystal fiber laser has been designed, constructed and characterized in order to examine the feasibility of this kind of devices for secure communications applications based on two identical chaotic lasers. Inclusion of a tailored photonic crystal fiber as active medium improves considerably the security of the device because it allows customization of the mode transversal profile, very influential on the laser dynamics and virtually impossible to be cloned by undesired listeners. The laser design has been facilitated by the combination of characterization procedures and models developed by us, which allow prediction of the most suitable laser features (losses, length of active fiber, etc.) to a given purpose (in our case, a laser that emits chaotically for a wide assortment of pump modulation conditions). The chaotic signals obtained have been characterized by means of topological analysis techniques. The underlying chaotic attractors found present topological structures belonging to classes of which very scarce experimental results have been reported. This fact is interesting from the point of view of the study of nonlinear systems and, besides, it is promising for secure communications: the stranger the signals, the more difficult for an eavesdropper to synthesize another system with similar dynamics.

  16. GPC Light Shaper for energy efficient laser materials processing

    DEFF Research Database (Denmark)

    Bañas, Andrew Rafael; Palima, Darwin; Villangca, Mark Jayson

    The biggest use of lasers is in materials processing. In manufacturing, lasers are used for cutting, drilling, marking and other machining processes. Similarly, lasers are important in microfabrication processes such as photolithography, direct laser writing, or ablation. Lasers are advantageous...

  17. Thermoelectric material comprising scandium doped zinc cadmium oxide

    DEFF Research Database (Denmark)

    2016-01-01

    There is presented a composition of scandium doped Zinc Cadmium Oxide with the general formula ZnzCdxScyO which the inventors have prepared, and for which material the inventors have made the insight that it is particularly advantageous as an n-type oxide material, such as particularly advantageous...

  18. Metal oxide charge transport material doped with organic molecules

    Science.gov (United States)

    Forrest, Stephen R.; Lassiter, Brian E.

    2016-08-30

    Doping metal oxide charge transport material with an organic molecule lowers electrical resistance while maintaining transparency and thus is optimal for use as charge transport materials in various organic optoelectronic devices such as organic photovoltaic devices and organic light emitting devices.

  19. Influence of wavelength on laser doping and laser-fired contact processes for c-Si solar cells

    Science.gov (United States)

    Molpeceres, Carlos; Sánchez-Aniorte, María. Isabel; Morales, Miguel; Muñoz, David; Martín, Isidro; Ortega, Pablo; Colina, Mónica; Voz, Cristóbal; Alcubilla, Ramón

    2012-10-01

    This work investigates the influence of the laser wavelength on laser doping (LD) and laser-fired contact (LFC) formation in solar cell structures. We compare the results obtained using the three first harmonics (corresponding to wavelengths of 1064 nm, 532 nm and 355 nm) of fully commercial solid state laser sources with pulse width in the ns range. The discussion is based on the impact on the morphology and electrical characteristics of test structures. In the case of LFC the study includes the influence of different passivation layers and the assessment of the process quality through electrical resistance measurements of an aluminium single LFC point for the different wavelengths. Values for the normalized LFC resistance far below 1.0 mΩcm2 have been obtained, with better results at shorter wavelengths. To assess the influence of the laser wavelength on LD we have created n+ regions into p-type c-Si wafers, using a dry LD approach to define punctual emitters. J-V characteristics show exponential trends at mid-injection for a broad parametric window in all wavelengths, with local ideality factors well below 1.5. In both processes the best results have been obtained using green (532 nm) and, specially, UV (355 nm). This indicates that to minimize the thermal damage in the material is a clear requisite to obtain the best electrical performance, thus indicating that UV laser shows better potential to be used in high efficiency solar cells.

  20. Characterization and laser performance of a new material: 2 at. % Nd:YAG grown by the Czochralski method.

    Science.gov (United States)

    L'huillier, Johannes A; Bitz, Gunter; Wesemann, Volker; von Loewis of Menar, Patric; Wallenstein, Richard; Borsutzky, Annette; Ackermann, Lothar; Dupré, Klaus; Rytz, Daniel; Vernay, Sophie

    2002-07-20

    We report on the optical quality and laser performance of Czochralski-grown 2-at. %-doped Nd:YAG. Using a diode pumped laser in an end pumped configuration, we compare the laser performance of this material with the performance of 1-at. %-doped Nd:YAG and 0.7-at. %-doped Nd:YVO4 crystals. Experimental results show the superior performance of 2-at. % Nd:YAG over Nd:YVO4. With a pump power of 25.7 W, a maximum output power of 12.3 W with a slope efficiency of 57% and an optical-to-optical efficiency of 48% were achieved.

  1. Femtosecond Laser Interaction with Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Roos, E; Benterou, J; Lee, R; Roeske, F; Stuart, B

    2002-03-25

    Femtosecond laser ablation shows promise in machining energetic materials into desired shapes with minimal thermal and mechanical effects to the remaining material. We will discuss the physical effects associated with machining energetic materials and assemblies containing energetic materials, based on experimental results. Interaction of ultra-short laser pulses with matter will produce high temperature plasma at high-pressure which results in the ablation of material. In the case of energetic material, which includes high explosives, propellants and pyrotechnics, this ablation process must be accomplished without coupling energy into the energetic material. Experiments were conducted in order to characterize and better understand the phenomena of femtosecond laser pulse ablation on a variety of explosives and propellants. Experimental data will be presented for laser fluence thresholds, machining rates, cutting depths and surface quality of the cuts.

  2. Laser applications in machining slab materials

    Science.gov (United States)

    Zhang, Xiaoping

    1990-10-01

    Since the invention of the laser back in 1960, laser technology has been extensively applied in many fields of science and technology. These has been a history of nearly two decades of using lasers as an energy source in machining materials, such as cutting, welding, ruling and boring, among other operations. With the development of flexible automation in production, the advantages of laser machining have has grown more and more obvious. The combination of laser technology and computer science further promotes the enhancement and upgrading of laser machining and related equipment. At present, many countries are building high quality laser equipment for machining slab materials, such as the Coherent and Spectra Physics corporations in the United States, the Trumpf Corporation in West Germany, the Amada Corporation in Japan, and the Bystronic Corporation in Switzerland, among other companies.

  3. Pulsed laser interference patterning of polyimide grating for dye-doped polymer laser

    Science.gov (United States)

    Kok, Soon Yie; Tou, Teck Yong; Yap, Seong Ling; Yap, Seong Shan

    2016-07-01

    Direct laser interference patterning of polyimide (PI) films was performed by using a pulsed 355-nm laser. At laser fluence of 0.4 J/cm2, gratings with spatial periods of 3.8 μm to 344 nm were created. The highest aspect ratio of the grating structure (0.8) was obtained for the 344-nm grating. An all-polymer dye laser was then fabricated by spin-coating a layer of disodium fluorescein (DF)-doped polyvinyl alcohol (PVA) film on bare and patterned PI substrate. Green laser emission was obtained when transversely pumped by a 355-nm laser. The lasing threshold reduced by ˜10 times for the sample with 344-nm grating while the laser intensity was ˜18 times higher. The enhancements are ascribed to the 344-nm grating structures, which act as an efficient distributed feedback resonator and distributed Bragg reflector grating for DF-doped PVA emitting at ˜563 nm, on top of being a passive light-trapping structures.

  4. Calculated and Experimental Research of Sheet Resistances of Laser-Doped Silicon Solar Cells

    Science.gov (United States)

    Li, Tao; Wang, Wen-Jing

    2015-02-01

    The calculated and experimental research of sheet resistances of crystalline silicon solar cells by dry laser doping is investigated. The nonlinear numerical model on laser melting of crystalline silicon and liquid-phase diffusion of phosphorus atoms by dry laser doping is analyzed by the finite difference method implemented in MATLAB. The melting period and melting depth of crystalline silicon as a function of laser energy density is achieved. The effective liquid-phase diffusion of phosphorus atoms in melting silicon by dry laser doping is confirmed by the rapid decrease of sheet resistances in experimental measurement. The plateau of sheet resistances is reached at around 15Ω/□. The calculated sheet resistances as a function of laser energy density is obtained and the calculated results are in good agreement with the corresponding experimental measurement. Due to the successful verification by comparison between experimental measurement and calculated results, the simulation results could be used to optimize the virtual laser doping parameters.

  5. High repetition rate Q-switched Er3+-doped fiber ring laser

    DEFF Research Database (Denmark)

    Sejka, Milan; Poulsen, Christian; Shi, Yuan

    1993-01-01

    In this paper we present for the first time Q switched Er-doped fibre laser utilising a ring Fabry-Perot cavity......In this paper we present for the first time Q switched Er-doped fibre laser utilising a ring Fabry-Perot cavity...

  6. Erbium Doped GaN Lasers by Optical Pumping

    Science.gov (United States)

    2016-07-13

    control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. Texas Technical University Box 41035 349 Admin Bldg Lubbock, TX 79409 -1035...obtained via growth by hydride vapor phase epitaxy (HVPE) in conjunction with a laser-lift-off (LLO) process . An Er doping level of 1.4 × 10^20 atoms/cm3...GPA to 4.0 (4.0 max scale): Number of graduating undergraduates funded by a DoD funded Center of Excellence grant for Education , Research and

  7. Development of laser materials processing and laser metrology techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol Jung; Chung, Chin Man; Kim, Jeong Mook; Kim, Min Suk; Kim, Kwang Suk; Baik, Sung Hoon; Kim, Seong Ouk; Park, Seung Kyu

    1997-09-01

    The applications of remote laser materials processing and metrology have been investigated in nuclear industry from the beginning of laser invention because they can reduce the risks of workers in the hostile environment by remote operation. The objective of this project is the development of laser material processing and metrology techniques for repairing and inspection to improve the safety of nuclear power plants. As to repairing, we developed our own laser sleeve welding head and innovative optical laser weld monitoring techniques to control the sleeve welding process. Furthermore, we designedand fabricated a 800 W Nd:YAG and a 150 W Excimer laser systems for high power laser materials processing in nuclear industry such as cladding and decontamination. As to inspection, we developed an ESPI and a laser triangulation 3-D profile measurement system for defect detection which can complement ECT and UT inspections. We also developed a scanning laser vibrometer for remote vibration measurement of large structures and tested its performance. (author). 58 refs., 16 tabs., 137 figs.

  8. Influence of laser doping on nanocrystalline ZnO thin films gas sensors

    Directory of Open Access Journals (Sweden)

    Yue Hou

    2017-08-01

    Full Text Available The effect of laser doping of Al on the gas sensing behavior of nanocrystalline ZnO thin films is reported. The doping of Al was carried out by the spin-coating of Al-precursors on nanocrystalline ZnO films followed by a pulsed laser irradiation. The laser-doped films were characterized as a function of laser power density by measuring the optical, structural, electrical, morphological and gas sensing properties of ZnO films. It was found that the laser doping process resulted in an increase of electrical conductivity of ZnO films. The performance of gas sensor was investigated for different concentrations of H2 and NH3 in the air. The results indicate that the laser doping process can be utilized to improve the sensor characteristics such as sensitivity and response time by optimization of laser power density. The optimum laser power is interpreted as the critical power level required to compete the effective doping versus developing the effective grain boundaries. Also, the selectivity of laser-doped ZnO sensors for H2 was studied for a likelihood practical gas mixture composed of H2, NH3 and CH4. It is found that these films can be optimized to develop H2 and NH3 sensors in PPM level with a higher selectivity over other reducing gases.

  9. Low-temperature micro-photoluminescence spectroscopy on laser-doped silicon with different surface conditions

    Science.gov (United States)

    Han, Young-Joon; Franklin, Evan; Fell, Andreas; Ernst, Marco; Nguyen, Hieu T.; Macdonald, Daniel

    2016-04-01

    Low-temperature micro-photoluminescence spectroscopy (μ-PLS) is applied to investigate shallow layers of laser-processed silicon for solar cell applications. Micron-scale measurement (with spatial resolution down to 1 μm) enables investigation of the fundamental impact of laser processing on the electronic properties of silicon as a function of position within the laser-processed region, and in particular at specific positions such as at the boundary/edge of processed and unprocessed regions. Low-temperature μ-PLS enables qualitative analysis of laser-processed regions by identifying PLS signals corresponding to both laser-induced doping and laser-induced damage. We show that the position of particular luminescence peaks can be attributed to band-gap narrowing corresponding to different levels of subsurface laser doping, which is achieved via multiple 248 nm nanosecond excimer laser pulses with fluences in the range 1.5-4 J/cm2 and using commercially available boron-rich spin-on-dopant precursor films. We demonstrate that characteristic defect PL spectra can be observed subsequent to laser doping, providing evidence of laser-induced crystal damage. The impact of laser parameters such as fluence and number of repeat pulses on laser-induced damage is also analyzed by observing the relative level of defect PL spectra and absolute luminescence intensity. Luminescence owing to laser-induced damage is observed to be considerably larger at the boundaries of laser-doped regions than at the centers, highlighting the significant role of the edges of laser-doped region on laser doping quality. Furthermore, by comparing the damage signal observed after laser processing of two different substrate surface conditions (chemically-mechanically polished and tetramethylammonium hydroxide etched), we show that wafer preparation can be an important factor impacting the quality of laser-processed silicon and solar cells.

  10. Laser Cutting of Different Materials

    Directory of Open Access Journals (Sweden)

    Kadir ÇAVDAR

    2013-08-01

    Full Text Available In this paper; in general potential developments and trends of a particular machining field by extensively evaluating present studies of laser beam machining have been discussed. As it is indicated below, technical literatures have been subsumed under five major headlines: Experimental studies, reviews, optimization researches of the cutting parameters, theoretical modelling studies of laser beam cutting and academic studies relating to laser cutting

  11. Synchronization of chaotic erbium-doped fibre lasers and its application in secure communication

    Institute of Scientific and Technical Information of China (English)

    Zhang Sheng-Hai; Shen Ke

    2004-01-01

    We have investigated the synchronization of chaotic duabring erbium-doped fibre lasers using the delay feedback injection scheme. Numerical simulation shows that two chaotic dual-ring erbium-doped fibre lasers can be well synchro nized if the strengths of delay feedback and injection are suitable. Even though the effects of the noises and the difference between the two lasers are considered, the twins can still reach good synchronization. Secure communication could be realized using the scheme of message-masking based on the synchronization of the chaotic dual-ring erbium-doped fibre lasers.

  12. Holographic recording in a doubly doped lithium niobate crystal with two wavelengths: a blue laser diode and a green laser

    Science.gov (United States)

    Komori, Yuichi; Ishii, Yukihiro

    2010-08-01

    A doubly-doped LiNbO3 (LN) crystal has been well used as a nonvolatile two-wavelength recording material. By using two levels of the crystal, two-kind holograms can be recorded on one crystal; a hologram is recorded with a 405-nm blue laser diode (LD) for a deep Mn level, and another hologram is with a 532-nm green laser for a shallow Fe level. The recording capacity doubles. A 780-nm LD is non-volatile reconstructing source since the LD line is insensitive to both levels. Multiplexed reconstructed images are demonstrated by using a sharp angular selectivity of a volume LN crystal keeping Bragg condition with spherical reconstructions.

  13. Advancing radiation balanced lasers (RBLs) in rare-earth (RE)-doped solids

    Energy Technology Data Exchange (ETDEWEB)

    Hehlen, Markus Peter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-21

    These slides cover the following topics: Mid-IR lasers in crystals using two-tone RBL (Single-dopant two-tone RBLs: Tm3+, Er3+, and Co-doped two-tone RBLs: (Yb3+, Nd3+) and (Ho3+, Tm3+); Advanced approaches to RBL crystals (Precursor purification, Micro-pulling-down crystal growth, and Bridgman crystal growth); Advanced approaches to RBL fibers (Materials for RBL glass fibers, Micro-structured fibers for RBL, and Fiber preform synthesis); and finally objectives.

  14. Planar waveguide amplifiers and laser in erbium doped silica

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas; Kristensen, Martin

    1999-01-01

    The objective of this work was to develop optically amplifying planar waveguides, using erbium-doped germano-silicate glass films deposited by PECVD (Plasma Enhanced Chemical Vapour Deposition). The waveguides should exhibit enough gain to be useful as optical amplifiers in integrated planar ligh...... 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.......The objective of this work was to develop optically amplifying planar waveguides, using erbium-doped germano-silicate glass films deposited by PECVD (Plasma Enhanced Chemical Vapour Deposition). The waveguides should exhibit enough gain to be useful as optical amplifiers in integrated planar...... fluorescence level. In addition the first measurement of the diffusion coefficient of erbim in silica is presented and it is shown that erbium rich precipitates are formed in areas of high erbium concentration. The manufacturing of planar waveguide structures using RIE (Reactive Ion Etching) is described...

  15. Laser Materials and Laser Spectroscopy - A Satellite Meeting of IQEC '88

    Science.gov (United States)

    Wang, Zhijiang; Zhang, Zhiming

    1989-03-01

    The Table of Contents for the book is as follows: * Laser Materials * Laser Site Spectroscopy of Transition Metal Ions in Glass * Spectroscopy of Chromium Doped Tunable Laser Materials * Spectroscopic Properties of Nd3+ Ions in LaMgAl11O19 Crystal * Spectral Study and 2.938 μm Laser Emission of Er3+ in the Y3Al5O12 Crystal * Raman-infrared Spectra and Radiationless Relaxation of Laser Crystal NdAl3(BO3)4 * A Study on HB and FLN in BaFCl0.5Br0.5:Sm2+ at 77K * Pair-pumped Upconversion Solid State Lasers * CW Upconversion Laser Action in Neodymium and Erbium doped Solids * Ultra-high Sensitive Upconversion Fluorescence of YbF3 Doped with Trace Tm3+ and Er3+ * The Growth and Properties of NYAB and EYAB Multifunctional Crystal * Study on Fluorescence and Laser Light of Er3+ in Glass * Growth and Properties of Single Crystal Fibers for Laser Materials * A Study on the Quality of Sapphire, Ruby and Ti3+ Doped Sapphire Grown by Temperature Gradient Technique (TGT) and Czochralski Technique (CZ) * The Measurement of Output Property of Ti3+ Al2O3 Laser Crystal * An Xα Study of the Laser Crystal MgF2 : V2+ * Q-switched NAB Laser * Miniature YAG Lasers * Study of High Efficiency {LiF}:{F}^-_2 Color Center Crystals * Study on the Formation Conditions and Optical Properties of (F2+)H Color Center in NaCl:OH- Crystals * Novel Spectroscopic Properties of {LiF}:{F}^+_3 - {F}_2 Mixed Color Centers Laser Crystals * Terraced Substrate Visible GaAlAs Semiconductor Lasers with a Large Optical Cavity * The Temperature Dependence of Gain Spectra, Threshold Current and Auger Recombination in InGaAsP-InP Double Heterojunction Laser diode * Time-resolved Photoluminescence and Energy Transfer of Bound Excitons in GaP:N Crystals * Optical Limiting with Semiconductors * A Critical Review of High-efficiency Crystals for Tunable Lasers * Parametric Scattering in β - BaB2O4 Crystal Induced by Picosecond Pulses * Generation of Picosecond Pulses at 193 nm by Frequency Mixing in β - BaB2O4

  16. Laser Materials Processing for NASA's Aerospace Structural Materials

    Science.gov (United States)

    Nagarathnam, Karthik; Hunyady, Thomas A.

    2001-01-01

    Lasers are useful for performing operations such as joining, machining, built-up freeform fabrication, and surface treatment. Due to the multifunctional nature of a single tool and the variety of materials that can be processed, these attributes are attractive in order to support long-term missions in space. However, current laser technology also has drawbacks for space-based applications. Specifically, size, power efficiency, lack of robustness, and problems processing highly reflective materials are all concerns. With the advent of recent breakthroughs in solidstate laser (e.g., diode-pumped lasers) and fiber optic technologies, the potential to perform multiple processing techniques in space has increased significantly. A review of the historical development of lasers from their infancy to the present will be used to show how these issues may be addressed. The review will also indicate where further development is necessary to realize a laser-based materials processing capability in space. The broad utility of laser beams in synthesizing various classes of engineering materials will be illustrated using state-of-the art processing maps for select lightweight alloys typically found on spacecraft. Both short- and long-term space missions will benefit from the development of a universal laser-based tool with low power consumption, improved process flexibility, compactness (e.g., miniaturization), robustness, and automation for maximum utility with a minimum of human interaction. The potential advantages of using lasers with suitable wavelength and beam properties for future space missions to the moon, Mars and beyond will be discussed. The laser processing experiments in the present report were performed using a diode pumped, pulsed/continuous wave Nd:YAG laser (50 W max average laser power), with a 1064 nm wavelength. The processed materials included Ti-6AI-4V, Al-2219 and Al-2090. For Phase I of this project, the laser process conditions were varied and optimized

  17. Functionally graded materials produced by laser cladding

    NARCIS (Netherlands)

    Pei, Y.T.; Hosson, J.Th.M. De

    2000-01-01

    AlSi40 functionally graded materials (FGMs) were produced by a one-step laser cladding process on cast Al-alloy substrate as a possible solution for interfacial problems often present in laser coatings. The microstructure of the FGMs consists of a large amount of silicon primary particles surrounded

  18. Functionally graded materials with laser cladding

    NARCIS (Netherlands)

    de Hosson, J.T.M.; Pei, Y.T.; Brebbia, CA

    2001-01-01

    Al-40 w/o Si functionally graded materials (FGMs) were produced by a onestep laser cladding process on cast Al-alloy substrate as a possible solution for interfacial problems often present in laser coatings. The microstructure of the FGMs consists of a large amount of silicon primary particles surro

  19. Functionally graded materials produced by laser cladding

    NARCIS (Netherlands)

    Pei, Y.T.; Hosson, J.Th.M. De

    2000-01-01

    AlSi40 functionally graded materials (FGMs) were produced by a one-step laser cladding process on cast Al-alloy substrate as a possible solution for interfacial problems often present in laser coatings. The microstructure of the FGMs consists of a large amount of silicon primary particles surrounded

  20. Functionally Graded Materials Produced by Laser Cladding

    NARCIS (Netherlands)

    Pei, Y.T.; Hosson, J.Th.M. De

    2000-01-01

    AlSi40 functionally graded materials (FGMs) were produced by a one-step laser cladding process on cast Al-alloy substrate as a possible solution for interfacial problems often present in laser coatings. The microstructure of the FGMs consists of a large amount of silicon primary particles surrounded

  1. Nonminimum Phase Behavior of Laser Material Processing

    NARCIS (Netherlands)

    Römer, G.R.B.E.; Weerkamp, N.P.; Meijer, J.; Postma, S.

    2001-01-01

    Optical sensors are increasingly applied in laser material processing to monitor and control the lasermaterial interaction zone. Dynamic models, relating the sensor signals (e.g. as temperature or molten area) to the process inputs (e.g. laser power or beam velocity), provide the basis for the desig

  2. Nanosecond laser ablation processes in aluminum-doped zinc-oxide for photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Canteli, D., E-mail: david.canteli@ciemat.es [Division de Energias Renovables, Energia Solar Fotovoltaica, CIEMAT, Avda. Complutense, 22, 28040 Madrid (Spain); Fernandez, S. [Division de Energias Renovables, Energia Solar Fotovoltaica, CIEMAT, Avda. Complutense, 22, 28040 Madrid (Spain); Molpeceres, C. [Centro Laser, Universidad Politecnica de Madrid, Ctra. de Valencia Km 7.3, 28031 Madrid (Spain); Torres, I.; Gandia, J.J. [Division de Energias Renovables, Energia Solar Fotovoltaica, CIEMAT, Avda. Complutense, 22, 28040 Madrid (Spain)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer A study of the ablation of AZO thin films deposited at different temperature conditions with nanosecond UV laser light for photovoltaic devices has been performed. Black-Right-Pointing-Pointer The ablation threshold of AZO thin films was measured and related with the absorption coefficient of the films at the laser wavelength, showing a direct correspondence. Black-Right-Pointing-Pointer A change in the material structure in the areas closest to the edges of laser grooves made in samples deposited at temperatures below 100 Degree-Sign C was observed and studied. - Abstract: Aiming to a future use in thin film solar modules, the processing of aluminum doped zinc oxide thin films with good optoelectronic properties with a nanosecond-pulsed ultraviolet laser has been studied. The ablation threshold fluence of the films has been determined and associated with the material properties. The ablation process has been optimized and grooves with good properties for photovoltaic devices have been obtained. The morphology of the ablated surfaces has been observed by confocal microscopy and its structure has been characterized by Raman spectroscopy. The influence of ablation parameters like focus distance, pulse energy and repetition frequency in the groove morphology has been studied with special attention to the thermal effects on the material structure.

  3. Optimization of the Laser Properties of Polymer Films Doped with N,N´-Bis(3-methylphenyl-N,N´-diphenylbenzidine

    Directory of Open Access Journals (Sweden)

    María A. Díaz-García

    2009-09-01

    Full Text Available This review compiles the work performed in the field of organic solid-state lasers with the hole-transporting organic molecule N,N´-bis(3-methylphenyl-N,N´-diphenylbenzidine system (TPD, in view of improving active laser material properties. The optimization of the amplified spontaneous emission characteristics, i.e., threshold, linewidth, emission wavelength and photostability, of polystyrene films doped with TPD in waveguide configuration has been achieved by investigating the influence of several materials parameters such as film thickness and TPD concentration. In addition, the influence in the emission properties of the inclusion of a second-order distributed feedback grating in the substrate is discussed.

  4. High Performance Large Mode-Area Ytterbium-doped Photonic Crystal Fiber for Fiber Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wei; Lu Peixiang [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074 (China); Li Shiyu; Wang Dongxiang, E-mail: chenwei@fiberhome.com.cn [State Key Laboratory of Optical Communication Technologies and Networks, Fiberhome Telecommunication Technologies Co. Ltd, 430074 (China)

    2011-02-01

    In this letter, large-mode-area double-cladding ytterbium-doped photonic crystal fiber was designed in theory and fabricated in practice. This fiber we have fabricated successfully has endless single mode operation performance and large inner-cladding numerical aperture of more than 0.75. The struts width between large air-holes in the outer-cladding is about 0.22 {mu}m. The photonic crystal fiber has a mode-area about 1465.7{mu}m{sup 2}. Due to the material being pure silica and air, such structures have excellent capacity to with-stand high temperature. The laser light can have very good beam quality, even diffraction-limited beam quality because of the single-mode core. This fabrication technical breakthrough of novelty high performance double-cladding ytterbium-doped photonic crystal fibers will give contributions to the high power fiber lasers and promote the progress of technology in the fields of high power lasers.

  5. Experimental study on all Yb-doped photonic crystal fiber laser

    Science.gov (United States)

    Fu, Jian; Hou, Zhiyun; Zhou, Guiyao; Zhao, Jingde; Zhang, Wei; Xia, Changming; Cang, Xuelong; Liu, Jiantao

    2017-02-01

    In this paper, we demonstrated an experiment of the all Yb-doped photonic crystal fiber laser using free space optical paths method. The experimental setup of all Yb-doped photonic crystal fiber laser is composed of the seed laser and the amplifier. The laser gain medium of the seed laser and the amplifier are the same Yb-doped photonic crystal fibers that are fabricated by non-chemical vapor deposition (Non-CVD) technology. The seed laser cavity is a Fabry-Perot cavity. The amplifier is pumped by back-end method. They are coupled each other by lens and dichroic mirrors on the optical table. The experimental results have a good reference value for the photonic crystal fiber laser research in the future.

  6. Widely tunable short-infrared thulium and holmium doped fluorozirconate waveguide chip lasers.

    Science.gov (United States)

    Lancaster, D G; Gross, S; Withford, M J; Monro, T M

    2014-10-20

    We report widely tunable (≈ 260 nm) Tm(3+) and Ho(3+) doped fluorozirconate (ZBLAN) glass waveguide extended cavity lasers with close to diffraction limited beam quality (M(2) ≈ 1.3). The waveguides are based on ultrafast laser inscribed depressed claddings. A Ti:sapphire laser pumped Tm(3+)-doped chip laser continuously tunes from 1725 nm to 1975 nm, and a Tm(3+)-sensitized Tm(3+):Ho(3+) chip laser displays tuning across both ions evidenced by a red enhanced tuning range of 1810 to 2053 nm. We also demonstrate a compact 790 nm diode laser pumped Tm(3+)-doped chip laser which tunes from 1750 nm to 1998 nm at a 14% incident slope efficiency, and a beam quality of M(2) ≈ 1.2 for a large mode-area waveguide with 70 µm core diameter.

  7. Multi-wavelength erbium-doped fiber laser using four-wave mixing effect in doped fiber

    Institute of Scientific and Technical Information of China (English)

    N.S.Shahabuddin; Z.Yusoff; H.Ahmad; S.W.Harun

    2011-01-01

    @@ We demonstrate a multi-wavelength erbium-doped fiber laser (EDFL) using erbium gain and four-wave mixing (FWM) effect in a piece of erbium-doped fiber (EDF) with high erbium ion concentration.The EDF has a pump absorption rate of 24.6 dB/m at 979 nm and is bi-directionally pumped by 980-nm laser diodes.FWM effect redistributes the energy of different oscillating lines and causes multi-wavelength operation.The laser generates more than 22 lines of optical comb with a line spacing of approximately 0.10 nm at the 1569-nm region using only 1.5-m-long EDF.%We demonstrate a multi wavelength erbium-doped fiber laser (EDFL) using erbium gain and four-wave mixing (FWM) effect in a piece of erbium-doped fiber (EDF) with high erbium ion concentration The EDF has a pump absorption rate of 24 6 dB/m at 979 nm and is bi-directionally pnmped by 980-nm laser diodes FWM effect redistributes the energy of different oscillating lines and causes multi-wavelength operation The laser generates more than 22 lines of optical comb with a line spacing of approximately 0.10 nm at the 1569-nm region using only 1.5-m-long EDF.

  8. Trends In Materials Processing With Laser Radiation

    Science.gov (United States)

    Herziger, G.; Kreutz, E. W.

    1989-04-01

    The objectives of reactive chemical and nonreactive thermal processing with laser radiation are outlined giving indication that processing with laser radiation is governed by a hierarchy of time constants originating from photon-matter interaction, phase transition dynamics, laser source excitation fluctuations,, and optical feedback in combination with the influence of beam delivery systems, processing/shielding gas flow configurations, robotics, production lines and environment. The minimization of losses by heat flow, reflection and transmission and the stringent need for quality assurance require as first approach the control of processing, which is mainly due to the capability of laser radiation source. The current status of laser radiation sources is reported giving information on the state of the art of processing with laser radiation in combination with subsequent demonstration of future trends and developments with respect to radiation sources, beam delivery, beam shaping, materials, processing and quality assurance.

  9. Trends in materials processsing with laser radiation

    Science.gov (United States)

    Herziger, Gerd; Kreutz, Ernst W.

    1989-03-01

    The objectives of reactive chemical and nonreactive thermal processing with laser radiation are outlined giving indication that processing with laser radiation is governed by a hierarchy of time constants originating from photon-matter interaction, phase transition dynamics, laser source excitation fluctuations, and optical feedback in combination with the influence of beam delivery systems, processing/shielding gas flow configurations, robotics, production lines and environment. The minimization of losses by heat flow, reflection and transmission and the stringent need for quality assurance require as first approach the control of processing, which is mainly due to the capability of laser radiation source. The current status of laser radiation sources is reported giving information on the state of the art of processing with laser radiation in combination with subsequent demonstration of future trends and developments with respect to radiation sources, beam delivery, beam shaping, materials, processing and quality assurance.

  10. PM567-Doped solid dye lasers based on PMMA

    Institute of Scientific and Technical Information of China (English)

    Li Xiao-Hui; Fan Rong-Wei; Xia Yuan-Qin; Liu Wei; Chen De-Ying

    2007-01-01

    Polymers are a kind of attractive hosts for laser dyes due to their high transparency in both pumping and lasing ranges and superior optical homogeneity. In this paper solid dye samples based on polymethyl methacrylate (PMMA)doped with different concentrations of 1, 3, 5, 7, 8 -pentamethyl-2, 6-diethylpyrromethene-BF2 (PM567) are prepaed.The absorption, fluorescence and lasing spectra of the samples are obtained. Wide absorption and fluorescence bands are obtained and a red shift of the maxima of the lasing emission spectra is observed. With the second-harmonic generation of Q-switched Nd:YAG laser (532 nm, ~20 ns) pumping the samples longitudinally, the slope efficiencies of the samples are obtained. There is an optimal dye concentration for the highest slope efficiency when the pumping energy is lower than some typical value (~250 m J), and the highest slope efficiency 35.6% is obtained in the sample with a dye concentration of 2 × 10-4 mol/L. Pumping the samples at a rate of 10Hz with a pulse energy as high as 200 mJ (the fluence is 0.2J/cm2), the output energy drops to one-half of its initial value after approximate 15500 pulses and the normalized photostability is 5.17GJ/mol. A kind of solid dye laser which could have some applications is built.

  11. Study on the characteristics of erbium-doped waveguide ring laser

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A theoretical model of the erbium-doped waveguide ring laser is established according to the theory of erbium-doped waveguide amplifier and the transmission matrix of waveguide directional coupler. The influence of bend radius, coupling coefficient and doped erbium ion concentration on the characteristics of waveguide ring laser is investigated. It is shown that due to the co-action of waveguide bend loss and other relevant loss there is an optimal bend radius which can provide simultaneously low threshold pumping power and high laser light output power. As one part of the resonator’s loss, the laser light coupling coefficient of directional coupler has an impact on the laser property. The analysis indicates that the laser achieves the high output power when the coupling coefficient is about 0.2. The threshold pumping power is the minimum when the doped erbium ion concentration is 0.85×1026 m-3. Increasing the concentration of doped erbium ions will enhance the output power of laser light as long as the concentration doesn’t introduce remarkable up-conversion effect. The results give a good theoretical basis for the design and fabrication of erbium-doped waveguide ring laser devices.

  12. Temperature Sensor Using a Multiwavelength Erbium-Doped Fiber Ring Laser

    Directory of Open Access Journals (Sweden)

    Silvia Diaz

    2017-01-01

    Full Text Available A novel temperature sensor is presented based on a multiwavelength erbium-doped fiber ring laser. The laser is comprised of fiber Bragg grating reflectors as the oscillation wavelength selecting filters. The performance of the temperature sensor in terms of both wavelength and laser output power was investigated, as well as the application of this system for remote temperature measurements.

  13. Localized devitrifiation in Er{sup 3+}-doped strontium barium niobate glass by laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Haro-Gonzalez, P.; Martin, I.R.; Lahoz, F.; Gonzalez-Perez, S. [Universidad de La Laguna, Departamento de Fisica Fundamental, Electronica y Sistemas, La Laguna, Tenerife (Spain); Capuj, N.E. [Universidad de La Laguna, Departamento de Fisica Basica, La Laguna, Tenerife (Spain); Jaque, D. [Universidad Autonoma de Madrid, Departamento de Fisica de Materiales, Madrid (Spain)

    2008-12-15

    Localized devitrifiation in strontium barium niobate glass doped with Er{sup 3+} under laser irradiation has been carried out. The samples of this study have been fabricated by the melt quenching method and doped with 5% mol of Er{sup 3+}. A 1.5-W cw Ar laser was focused on the sample to obtain devitrifiation of the glass. Evidence of the changes induced by the Ar laser has been observed through the analysis of the photoluminescence of the Er{sup 3+} ions. The transitions corresponding to {sup 2}H{sub 11/2}{yields}{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}{yields}{sup 4}I{sub 15/2} and {sup 4}F{sub 9/2}{yields}{sup 4}I{sub 15/2} have been studied to analyze structure changes. Microluminescence measurements have been carried out to spatially select positions inside and outside the irradiated area. We have observed changes in the emission bands corresponding to these transitions. The emission bands from Er{sup 3+} ions in the irradiated zone show a resolved structure while they are broadened outside that area. These changes in the optical properties of the Er{sup 3+} ions indicate that the Ar-laser irradiation has produced a change in the local structure of the material. These results show that a localized devitrifiation has been produced after the laser action and the transition from glass to glass ceramic has been completed. (orig.)

  14. Laser-Material Interaction of Powerful Ultrashort Laser Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Komashko, A

    2003-01-06

    Laser-material interaction of powerful (up to a terawatt) ultrashort (several picoseconds or shorter) laser pulses and laser-induced effects were investigated theoretically in this dissertation. Since the ultrashort laser pulse (USLP) duration time is much smaller than the characteristic time of the hydrodynamic expansion and thermal diffusion, the interaction occurs at a solid-like material density with most of the light energy absorbed in a thin surface layer. Powerful USLP creates hot, high-pressure plasma, which is quickly ejected without significant energy diffusion into the bulk of the material, Thus collateral damage is reduced. These and other features make USLPs attractive for a variety of applications. The purpose of this dissertation was development of the physical models and numerical tools for improvement of our understanding of the process and as an aid in optimization of the USLP applications. The study is concentrated on two types of materials - simple metals (materials like aluminum or copper) and wide-bandgap dielectrics (fused silica, water). First, key physical phenomena of the ultrashort light interaction with metals and the models needed to describe it are presented. Then, employing one-dimensional plasma hydrodynamics code enhanced with models for laser energy deposition and material properties at low and moderate temperatures, light absorption was self-consistently simulated as a function of laser wavelength, pulse energy and length, angle of incidence and polarization. Next, material response on time scales much longer than the pulse duration was studied using the hydrocode and analytical models. These studies include examination of evolution of the pressure pulses, effects of the shock waves, material ablation and removal and three-dimensional dynamics of the ablation plume. Investigation of the interaction with wide-bandgap dielectrics was stimulated by the experimental studies of the USLP surface ablation of water (water is a model of

  15. Characterization of nonlinear saturation and mode-locking potential of ionically-doped colored glass filter for short-pulse fiber lasers.

    Science.gov (United States)

    Zhang, M; Kelleher, E J R; Popov, S V; Taylor, J R

    2013-05-20

    The nonlinear saturable absorption of an ionically-doped colored glass filter is measured directly using a Z-scan technique. For the first time, we demonstrate the potential of this material as a saturable asborber in fiber lasers. We achieve mode-locking of an ytterbium doped system. Mode-locking of cavities with all-positive and net-negative group velocity dispersion are demonstrated, achieving pulse durations of 60 ps and 4.1 ps, respectively. This inexpensive and optically robust material, with the potential for broadband operation, could surplant other saturable absorber devices in affordable mode-locked fiber lasers.

  16. Study of Doped ZnO Films Synthesized by Combining Vapor Gases and Pulsed Laser Deposition

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Lehoczky, Sandor L.; George, M. A.

    2000-01-01

    The properties and structure of the ZnO material are similar to those of the GaN. Since an excitonic binding energy of ZnO is about 60 meV, it has strong potential for excitonic lasing at the room temperature. This makes synthesizing ZnO films for applications attractive. However, there are several hurdles in fabricating electro-optical devices from ZnO. One of those is in growing doped p-type ZnO films. Although techniques have been developed for the doping of both p-type and n-type ZnO, this remains an area that can be improved. In this presentation, we will report the experimental results of using both thermal vapor and pulsed laser deposition to grow doped ZnO films. The films are deposited on (0001) sapphire, (001) Si and quartz substrates by ablating a ZnO target. The group III and V elements are introduced into the growth chamber using inner gases. Films are characterized by x-ray diffraction, scanning probe microscopy, energy dispersive spectroscopy, Auger electron spectroscopy, and electrical measurements. The full width at half maximum of theta rocking curves for epitaxial films is less than 0.5 deg. In textured films, it rises to several degrees. Film surface morphology reveals an island growth pattern, but the size and density of these islands vary with the composition of the reactive gases. The electrical resistivity also changes with the doped elements. The relationship between the doping elements, gas composition, and film properties will be discussed.

  17. Multiwavelength erbium-doped fiber laser based on graphene oxide.

    Science.gov (United States)

    Hao, Xia; Tong, Zhengrong; Zhao, Junfa; Cao, Ye; Li, Lan

    2014-07-10

    A multiwavelength erbium-doped fiber (EDF) laser based on graphene oxide (GO) has been proposed, to the best of our knowledge, for the first time, to generate an output of stable wavelengths. The structure mainly comprises a few layers of GO between two single-mode fibers incorporated into a capillary device and a Lyot comb filter. GO can show a good nonlinear optical effect, which is beneficial to suppress the mode competition caused by the EDF and stabilize the multiwavelength output. With assistance from the GO device, 11 stable simultaneous lasing signals with a power nonuniformity of about 1.5 dB are obtained. Wavelength spacing is about 0.42 nm and the linewidth of each wavelength is less than 0.07 nm.

  18. Chaos synchronization characteristics in erbium-doped fiber laser systems

    Science.gov (United States)

    Imai, Y.; Murakawa, H.; Imoto, T.

    2003-03-01

    Chaos synchronization characteristics in the master-slave and slave-slave systems with modulated erbium-doped fiber lasers are investigated numerically. We find that synchronization state of chaos becomes better, i.e., the correlation coefficient between the two outputs reaches unity, as the difference in the input power between the two subsystems decreases and is not dependent strongly upon the difference in the modulation index in both the master-slave and slave-slave systems. In the master-slave system, the highest correlation coefficient is attained at the smaller pump power and the larger modulation index in the slave subsystem than those in the master subsystem. On the other hand, the correlation coefficient equal to unity is achieved with the identical parameters in the slave 1 and 2 subsystems in the slave-slave system.

  19. Polysulfone as a scintillation material without doped fluorescent molecules

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hidehito, E-mail: hidehito@rri.kyoto-u.ac.jp [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kitamura, Hisashi [National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Sato, Nobuhiro; Kanayama, Masaya [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Shirakawa, Yoshiyuki [Kobe University, 1-1, Rokkodai, Nada, Kobe 657-8501 (Japan); Takahashi, Sentaro [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

    2015-10-11

    Scintillation materials made from un-doped aromatic ring polymers can be potentially used for radiation detection. Here we demonstrate that Polysulfone (PSU) works without doped fluorescent guest molecules, and thus broadens the choices available for radiation detection. The transparent PSU substrate (1.24 g/cm{sup 3}) significantly absorbs short-wavelength light below approximately 350 nm. Visible light absorption colours the substrate slightly yellow, and indigo blue fluorescence is emitted. The fluorescence maximum occurs at the intersection of the 340-nm excitation and 380-nm emission spectra; thus the emission is partially absorbed by the substrate. An effective refractive index of 1.70 is derived based on the wavelength dependence of the refractive indices and the emission spectrum. A peak caused by 976-keV internal-conversion electrons from a {sup 207}Bi radioactive source appears in the light yield distribution. The light yield is equivalent to that of poly (phenyl sulfone), which has a similar structure. Overall, un-doped PSU could be a component substrate in polymer blends and be used as an educational tool in radiation detection. - Highlights: • Polysulfone (PSU) is a scintillation material that does not require doping. • PSU is slightly yellow. • Indigo blue light with 380-nm emission maximum is emitted. • An effective refractive index of 1.70 was derived. • A peak caused by mono-energetic internal-conversion electrons appears in the light yield distribution.

  20. Spectroscopic and laser properties of Er{sup 3+} doped fluoro-phosphate glasses as promising candidates for broadband optical fiber lasers and amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Babu, S. [Department of Physics, Sri Venkateswara University, Tirupati 517 502, A.P. (India); Seshadri, M. [Institute of Physics, University of Campinas, UNICAMP, P.O. Box 6165, Campinas 13083-970 (Brazil); Reddy Prasad, V. [Department of Physics, Sri Venkateswara University, Tirupati 517 502, A.P. (India); Ratnakaram, Y.C., E-mail: ratnakaramsvu@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati 517 502, A.P. (India)

    2015-10-15

    Highlights: • Erbium doped different fluoro-phosphate glasses are prepared and characterized. • Spectroscopic properties have been determined using Judd–Ofelt and Mc-Cumber theory. • Prominent laser transition Er{sup 3+}:{sup 4}I{sub 13/2} → {sup 4}I{sub 15/2} is observed at 1.53 μm. - Abstract: Different fluoro-phosphate glasses doped with 0.5 mol% Er{sup 3+} doped are prepared by melt quenching method. Both structural and spectroscopic properties have been characterized in order to evaluate their potential as both laser source and amplifier materials. Optical absorption measurements are carried out and analyzed through Judd–Ofelt and Mc-Cumber theories where spectroscopic parameters such as intensity parameters Ω{sub l} (λ = 2,4,6), transition probabilities, radiative lifetimes, stimulated absorption cross-sections and emission cross-sections at 1.5 μm have been evaluated for Er{sup 3+} doped different fluorophosphate glasses. The various luminescence and gain properties are explained from photoluminescence studies. The decay curve analysis have been done for obtaining the decay time constants of Er{sup 3+} excited level {sup 4}I{sub 13/2} in all the fluoro-phosphate glasses. The obtained results of each glass matrix are compared with the equivalent parameters for several other host glasses. These fluoro-phosphate glasses are found to be suitable candidates for laser and amplifier applications.

  1. Laser induced damage in optical materials: 1989

    Science.gov (United States)

    Bennett, H. E.; Chase, L. L.; Guenther, A. H.; Newnam, B. E.; Soileau, M. J.

    1990-10-01

    The 21st Annual Symposium on Optical Materials for High Power Lasers was divided into sessions concerning Materials and Measurements, Mirrors and Surfaces, Thin Films, and, finally, Fundamental Mechanisms. As in previous years, the emphasis of the papers presented was directed toward new frontiers and new developments. Particular emphasis was given to materials for high power apparatus. The wavelength range of the prime interest included surface characterization, thin film substrate boundaries, and advances in fundamental laser matter threshold interactions and mechanisms. The scalling of damage thresholds with pulse duration, focal area, and wavelength was discussed in detail.

  2. Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials

    Energy Technology Data Exchange (ETDEWEB)

    Achatz, Philipp

    2009-05-15

    During this PhD project, the metal-insulator transition and superconductivity of highly boron-doped single crystal diamond and related materials have been investigated. The critical boron concentration n{sub c} for the metal-insulator transition was found to be the same as for the normal-superconductor transition. All metallic samples have been found to be superconducting and we were able to link the occurence of superconductivity to the proximity to the metal-insulator transition. For this purpose, a scaling law approach based on low temperature transport was proposed. Furthermore, we tried to study the nature of the superconductivity in highly boron doped single crystal diamond. Raman spectroscopy measurements on the isotopically substituted series suggest that the feature occuring at low wavenumbers ({approx} 500 cm{sup -1}) is the A1g vibrational mode associated with boron dimers. Usual Hall effect measurements yielded a puzzling situation in metallic boron-doped diamond samples, leading to carrier concentrations up to a factor 10 higher than the boron concentration determined by secondary ion mass spectroscopy (SIMS). The low temperature transport follows the one expected for a granular metal or insulator, depending on the interplay of intergranular and intragranular (tunneling) conductance. The metal-insulator transition takes place at a critical conductance g{sub c}. The granularity also influences significantly the superconducting properties by introducing the superconducting gap {delta} in the grain and Josephson coupling J between superconducting grains. A peak in magnetoresistance is observed which can be explained by superconducting fluctuations and the granularity of the system. Additionally we studied the low temperature transport of boron-doped Si samples grown by gas immersion laser doping, some of which yielded a superconducting transition at very low temperatures. Furthermore, preliminary results on the LO-phonon-plasmon coupling are shown for the

  3. Thermal lensing of laser materials

    Science.gov (United States)

    Davis, Mark J.; Hayden, Joseph S.

    2014-10-01

    This paper focuses on the three main effects that can induce wave-front distortion due to thermal lensing in laser gain media: 1) thermo-optic (dn/dT); 2) stress-optic; and 3) surface deformation (e.g., "end-bulging" of a laser rod). Considering the simple case of a side-pumped cylindrical rod which is air- or water-cooled along its length, the internal temperature distribution has long been known to assume a simple parabolic profile. Resulting from this are two induced refractive index variations due to thermo-optic and stress-optic effects that also assume a parabolic profile, but generally not of the same magnitude, nor even of the same sign. Finally, a small deformation on the rod ends can induce a small additional lensing contribution. We had two goals in this study: a) use finite-element simulations to verify the existing analytical expressions due to Koechner1 and Foster and Osterink; and b) apply them to glasses from the SCHOTT laser glass portfolio. The first goal was a reaction to more recent work by Chenais et al. who claimed Koechner made an error in his analysis with regard to thermal stress, throwing into doubt conclusions within studies since 1970 which made use of his equations. However, our re-analysis of their derivations, coupled with our FE modeling, confirmed that the Koechner and Foster and Osterink treatments are correct, and that Chenais et al. made mistakes in their derivation of the thermally-induced strain. Finally, for a nominal laser rod geometry, we compared the thermally-induced optical distortions in LG-680, LG-750, LG-760, LG-770, APG-1, and APG-2. While LG-750, -760, and -770 undergo considerable thermo-optic lensing, their stress-optic lensing is nearly of the same magnitude but of opposite sign, leading to a small total thermal lensing signature.

  4. Diamond: a material for laser spectroscopy

    Science.gov (United States)

    Castex, M. C.; Riedel, D.; Museur, L.; Chardonnet, Christian; Gicquel, Alix; Foulon, Francois; Borel, C.; Bergonzo, P.; Jany, C.

    1998-10-01

    Diamond polycrystalline films synthesized by chemical vapor deposition techniques present interesting feature for laser spectroscopy due to several advantages arising from their optical, electronic, thermal and mechanical properties. Their wide transmission band from the far IR to the UV make them attractive as optical devices for high-power laser beam. Moreover, with a wide band gap, a short carrier lifetime and a high damage threshold, diamond is an ideal semiconductor material for the fabrication of fast and solar blind VUV detectors. We report here results of laser studies performed with tow different objectives. With use of a pulsed VUV laser at 125 nm we have determined the photoconductive response of polycrystalline diamond detectors. With a CO2 laser we have investigated the polarization properties of auto-supported films having thicknesses smaller than the wavelength.

  5. Continuously Tunable Erbium-Doped Fiber Ring Laser Using Fiber Bragg Grating

    Directory of Open Access Journals (Sweden)

    S. W. Harun H. Ahmad and P. Poopalan

    2012-08-01

    Full Text Available An efficient tunable erbium-doped fiber (EDF ring laser utilizing a single fiber Bragg grating (FBG and an optical circulator is investigated. The laser demonstrates a threshold of 3.43 mW and a slope efficiency of 12.5%. Tunability of the fiber laser is obtained by thermal tuning of the FBG. Simultaneous temperature tuning demonstrates a 0.01 nm/oC variation in laser wavelength.Key Words:  Fiber Bragg grating, fiber laser, tunable laser, ring laser, thermal tuning

  6. Pulsed Laser Processing of Paper Materials

    Science.gov (United States)

    Schechtel, Florian; Reg, Yvonne; Zimmermann, Maik; Stocker, Thomas; Knorr, Fabian; Mann, Vincent; Roth, Stephan; Schmidt, Michael

    At present the trends in paper and packaging industries are the personalization of products and the use of novel high-tech materials. Laser processes as non-contact and flexible techniques seem to be the obvious choice to address those developments. In this paper we present a basic understanding of the occurring mechanisms of laser based engraving of different paper and paperboard materials, using a picosecond laser source at 1064 nm. The influences on the beam-paper-interaction of grammage, the composition of the paper matrix, as well as the paper inherent cellulose fibers were investigated. Here the ablation threshold of commercially available paper was determined and a matrix ablation effect under the 1064 nm radiation observed. These results were characterized and qualified mainly by means of laser scanning microscope (LSM) micrographs in combination with color-space analytics.

  7. Efficient high power 2 micron Tm3+-Doped Fiber Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of new Tm3+ doped germanate glass fibers for efficient high power 2 micron fiber lasers capable of generating an output power of...

  8. Graphene oxide mode-locked femtosecond erbium-doped fiber lasers

    National Research Council Canada - National Science Library

    Xu, Jia; Liu, Jiang; Wu, Sida; Yang, Quan-Hong; Wang, Pu

    2012-01-01

    We demonstrated the femtosecond erbium-doped all-fiber lasers mode-locked with graphene oxide, which can be conveniently obtained from natural graphite by simple oxidation and ultra-sonication process...

  9. Tunable Erbium-Doped Fiber Laser Based on Random Distributed Feedback

    National Research Council Canada - National Science Library

    Lulu Wang; Xinyong Dong; Shum, Perry Ping; Haibin Su

    2014-01-01

    A tunable erbium-doped fiber (EDF) laser based on random distributed feedback through backward Rayleigh scattering in a 20-km-long single-mode fiber and a tunable fiber Fabry-Perot interferometer filter is demonstrated...

  10. Active mode-locking via pump modulation in a Tm-doped fiber laser

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2016-10-01

    Full Text Available We propose and experimentally realize a new class of actively mode-locking technique using pump modulation for rare-earth doped fiber lasers. A Tm-doped fiber laser at 2 μm is mode-locked using the proposed active mode-locking via pump modulation technique. Low-threshold continuous-wave mode-locking is achieved with a transform-limited pulse width of 4.4 ps, a spectral bandwidth of 0.9 nm, and a repetition rate of 12.9 MHz. Second-harmonic mode-locking is also demonstrated by simply driving the pump current at an appropriate frequency. More importantly, we believe that this technique can be applied to mode-lock other rare-earth doped fiber laser systems such as erbium- and ytterbium-doped fiber lasers.

  11. Efficient High Power 2 micron Tm3+-Doped Fiber Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of new Tm3+ doped germanate glass fibers for efficient high power 2-micron fiber lasers capable of generating an output power of...

  12. A new bismuth-doped fibre laser, emitting in the range 1625 – 1775 nm

    Energy Technology Data Exchange (ETDEWEB)

    Dianov, E M; Firstov, S V; Alyshev, S V; Riumkin, K E; Shubin, A V; Medvedkov, O I; Mel' kumov, M A [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Khopin, V F; Gur' yanov, A N [G.G.Devyatykh Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

    2014-06-30

    CW lasing of a Bi-doped germanosilicate fibre in a wavelength range that covers the spectral region between the emission bands of Er and Tm fibre lasers has been demonstrated for the first time. (letters)

  13. Graphene thickness-dependent Er-doped Q-switched optical fiber laser

    Science.gov (United States)

    Wang, Xiaolong; Sang, Mei; Zhu, Pan; Liu, Ke; Yang, Tianxin

    2013-02-01

    A stable Q-switched laser is useful in the area of remote sensing, range finding, optical imaging, material processing, and fiber communications. With its excellent linear and nonlinear optical characteristics, graphene has been proven to be an attractive material to generate nanosecond, picosecond and femtosecond laser pulses. It has a lot of advantages, such as lower saturation intensity, larger saturable-absorption modulation depth, higher damage threshold, sub-picosecond recovery time and an ultrabroad wavelength-independent saturable-absorption range. In this paper, we demonstrate a graphene based Q-switched fiber laser. Graphene was deposited on the fiber interface by the optically driven deposition method. The thickness of the graphene can be controlled by changing depositing time. The compact Q-switched erbium-doped fiber laser based on graphene operated stably, and got Q-switched pulse sequences output with the repetition rate of 19KHz and the average power of 1.4mW when pump power is 40mW. Higher peak power, shorter pulse duration, and higher repetition rate could be achieved by adjusting the thickness of the graphene layer appropriately. Besides, the pulse duration and output power is proved to be a function of the pump power. The repetition rate of this fiber laser had a characteristic of monotonically increasing, near-linear with the changing of pump power. The stable Q-switching pulse output can be observed on the oscilloscope with differently specific repetition rate and pump power. Theory analysis of this fiber laser and further improvement methods is also studied combined with the experimental results.

  14. Single-frequency thulium-doped distributed-feedback fiber laser.

    Science.gov (United States)

    Agger, Søren; Povlsen, Jørn Hedegaard; Varming, Poul

    2004-07-01

    We have successfully demonstrated a single-frequency distributed-feedback (DFB) thulium-doped silica fiber laser emitting at a wavelength of 1735 nm. The laser cavity is less than 5 cm long and is formed by intracore UV-written Bragg gratings with a phase shift. The laser is pumped at 790 nm from a Ti:sapphire laser and has a threshold pump power of 59 mW. The laser has a maximum output power of 1 mW in a single-frequency, single-polarization radiation mode and is tunable over a few nanometers. To the best of the authors' knowledge, this is the first report of a single-frequency DFB fiber laser that uses thulium as the amplifying medium. The lasing wavelength is the longest demonstrated with DFB fiber lasers and yet is among the shortest obtained for thulium-doped silica fiber lasers.

  15. Single-frequency thulium-doped distributed-feedback fibre laser

    DEFF Research Database (Denmark)

    Agger, Søren; Povlsen, Jørn Hedegaard; Varming, Poul

    2004-01-01

    We have successfully demonstrated a single-frequency distributed-feedback (DFB) thulium-doped silica fiber laser emitting at a wavelength of 1735 nm. The laser cavity is less than 5 cm long and is formed by intracore UV-written Bragg gratings with a phase shift. The laser is pumped at 790 nm from...... that uses thulium as the amplifying medium. The lasing wavelength is the longest demonstrated with DFB fiber lasers and yet is among the shortest obtained for thulium-doped silica fiber lasers....... a Ti:sapphire laser and has a threshold pump power of 59 mW. The laser has a maximum output power of 1 mW in a singlefrequency, single-polarization radiation mode and is tunable over a few nanometers. To the best of the authors’ knowledge, this is the first report of a single-frequency DFB fiber laser...

  16. Electrically tunable Yb-doped fiber laser based on a liquid crystal photonic bandgap fiber device

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin; Scolari, Lara; Wei, Lei

    2010-01-01

    We demonstrate electrical tunability of a fiber laser using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a tunable liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate...... an all-spliced laser cavity based on the liquid crystal photonic bandgap fiber mounted on a silicon assembly, a pump/signal combiner with single-mode signal feed-through and an ytterbium-doped photonic crystal fiber. The laser cavity produces a single-mode output and is tuned in the range 1040-1065 nm...

  17. Multimode laser emission from dye-doped hollow polymer optical fibre

    Indian Academy of Sciences (India)

    C L Linslal; Jaison Peter; S Mathew; M Kailasnath

    2014-02-01

    Well-resolved multimode laser emission was observed for the first time from a freestanding microring cavity based on Rhodamine B dye-doped hollow polymer optical fibre by transverse pumping. Fibres with different diameters such as 180, 460, 640 and 800 m were fabricated from a dye-doped hollow polymer preform. A blueshift in the mode structure was observed with decrease in fibre diameter leading to wide range tunability of the laser emission.

  18. Ytterbium-doped Q-switched fiber laser based upon manganese dioxide (MnOsub>2sub>) saturable absorber.

    Science.gov (United States)

    Hattori, Haroldo T; Khaleque, Abdul; Liu, Liming; Greck, Michael R

    2016-11-10

    Manganese dioxide (MnOsub>2sub>) is an abundant material that is widely used in many devices, such as alkaline batteries. At infrared frequencies, MnOsub>2sub> is lossy and strongly absorbs light. These characteristics make MnOsub>2sub> a potential candidate as a low-cost saturable absorber in Q-switched lasers. In this paper, we examine the performance of MnOsub>2sub> as a saturable absorber in an ytterbium-doped Q-switched fiber laser: we show that it can produce pulses with durations ranging from 300 to 1800 ns.

  19. DBR and DFB Lasers in Neodymium- and Ytterbium-Doped Photothermorefractive Glasses

    Science.gov (United States)

    Ryasnyanskiy, Aleksandr; Vorobiev, N.; Smirnov, V.; Lumeau, J.; Glebov, A.; Mokhun, O..; Spiegelberg, Ch.; Krainak, Michael A.; Glebov, A.; Glebov, L.

    2014-01-01

    The first demonstration, to the best of our knowledge, of distributed Bragg reflector (DBR) and monolithic distributed feedback (DFB) lasers in photothermorefractive glass doped with rare-earth ions is reported. The lasers were produced by incorporation of the volume Bragg gratings into the laser gain elements. A monolithic single-frequency solid-state laser with a line width of 250 kHz and output power of 150 mW at 1066 nm is demonstrated.

  20. Femtosecond laser fabrication of waveguides in Rhodamine B-doped GPTS/TEOS-derived organic/silica monolithic xerogel

    Science.gov (United States)

    Ferreira, P. H. D.; Otuka, A. J. G.; Barbano, E. C.; Manoel, D. S.; De Vicente, F. S.; Vollet, D. R.; Donatti, D. A.; Misoguti, L.; Mendonça, C. R.

    2015-09-01

    This paper reports on the fabrication and characterization of waveguides inside of a dye doped-organic/inorganic bulk material using femtosecond laser microfabrication. Rhodamine B-doped GPTS/TEOS-derived organic/silica monolithic xerogels with excellent optical quality were prepared by sol-gel method. The influence of the dye concentration on the samples optical properties was also investigated in order to choose the proper one to be used for producing the waveguides. After investigation of parameters to fabrication in xerogels, such as, scan speed effects and pulse energy, we produced waveguides in bulks doped with 0.5 mmol/L of Rhodamine B. Propagation losses in the single mode waveguides, at 632.8 nm wavelength, were obtained.

  1. Femtosecond laser excitation of dielectric materials

    DEFF Research Database (Denmark)

    Wædegaard, Kristian Juncher; Balling, Peter; Frislev, Martin Thomas

    2012-01-01

    We report an approach to modeling the interaction between ultrashort laser pulses and dielectric materials. The model includes the excitation of carriers by the laser through strongfield excitation, collisional excitation, and absorption in the plasma consisting of conduction-band electrons formed...... during the pulse itself. It will be described how the model allows for a self-consistent description of material excitation and light propagation. The model is used to predict ablation depths and the optical properties of the sample. A comparison between the calculation and experimentally determined...

  2. Laser induced forward transfer of soft materials

    Science.gov (United States)

    Palla-Papavlu, A.; Dinca, V.; Luculescu, C.; Shaw-Stewart, J.; Nagel, M.; Lippert, T.; Dinescu, M.

    2010-12-01

    A strong research effort is presently aimed at patterning methodologies for obtaining controlled defined micrometric polymeric structures for a wide range of applications, including electronics, optoelectronics, sensors, medicine etc. Lasers have been identified as appropriate tools for processing of different materials, such as ceramics and metals, but also for soft, easily damageable materials (biological compounds and polymers). In this work we study the dynamics of laser induced forward transfer (LIFT) with a gap between the donor and the receiver substrates, which is the basis for possible applications that require multilayer depositions with high spatial resolution.

  3. Status of fiber lasers study of on ytterbium doped fiber laser and laser spectroscopy of doped fibers; Etat de l`art des lasers a fibre, etude d`un laser a fibre dopee ytterbium et spectroscopie laser de fibres dopees

    Energy Technology Data Exchange (ETDEWEB)

    Magne, S.

    1994-07-01

    This work shows all the advantages and drawbacks of the rare-earth-doped fiber lasers and fiber optical amplifiers, pointing out their potential use for instrumentation and optical fiber sensor technology. The theory of light propagation in optical fibers is presented in order to understand the manufacturing methods. A comparative study of preform surface and concentration analysis is performed. The gain behaviour is also thoroughly examined. A synthesis of all technological parameters of the fiber laser is then established and all technologies of the constituting integrated components are reviewed and compared. The experimental techniques mainly involve: site selective excitation tunability, cooperative luminescence, oxidation state changes induced by gamma irradiation, ytterbium-doped mono-mode continuous wave tunable three-level fiber laser. (TEC). 622 refs., 176 figs.

  4. Exploratory development on laser and optical materials. Final report 1 Dec 1972-15 Aug 1974

    Energy Technology Data Exchange (ETDEWEB)

    O' Hare, J.M.; Detrio, J.A.; Petty, R.D.; Yaney, P.P.

    1974-12-01

    Topics include analytical solid state material studies--(Theoretical and experimental investigations of the optical Stark spectra of rare earth ions, Judd-Ofelt theory, Quantum efficiencies); Laser materials evaluation; Studies of rare-earth doped CdF/sub 2/, SrF/sub 2/, and BaF/sub 2/--(Electroluminescence of semiconducting CdF/sub 2/, Analyses of the optical spectra of Gd/sup 3 +/ and Ce/sup 3 +/).

  5. Target dependent femtosecond laser plasma implantation dynamics in enabling silica for high density erbium doping

    Science.gov (United States)

    Chandrappan, Jayakrishnan; Murray, Matthew; Kakkar, Tarun; Petrik, Peter; Agocs, Emil; Zolnai, Zsolt; Steenson, D. P.; Jha, Animesh; Jose, Gin

    2015-09-01

    Chemical dissimilarity of tellurium oxide with silica glass increases phase separation and crystallization tendency when mixed and melted for making a glass. We report a novel technique for incorporating an Er3+-doped tellurite glass composition into silica substrates through a femtosecond (fs) laser generated plasma assisted process. The engineered material consequently exhibits the spectroscopic properties of Er3+-ions, which are unachievable in pure silica and implies this as an ideal material for integrated photonics platforms. Formation of a well-defined metastable and homogeneous glass structure with Er3+-ions in a silica network, modified with tellurite has been characterized using high-resolution cross-sectional transmission electron microscopy (HRTEM). The chemical and structural analyses using HRTEM, Rutherford backscattering spectrometry (RBS) and laser excitation techniques, confirm that such fs-laser plasma implanted glasses may be engineered for significantly higher concentration of Er3+-ions without clustering, validated by the record high lifetime-density product 0.96 × 1019 s.cm-3. Characterization of planar optical layers and photoluminescence emission spectra were undertaken to determine their thickness, refractive indices and photoluminescence properties, as a function of Er3+ concentration via different target glasses. The increased Er3+ content in the target glass enhance the refractive index and photoluminescence intensity of the modified silica layer whilst the lifetime and thickness decrease.

  6. Analysis of influence factors on 2 μm Tm3+-doped fiber laser output characteristics

    Science.gov (United States)

    Yu, Miao; Jin, Guang-yong; Wang, Ji

    2016-10-01

    The affecting factors of 2 μm Tm3+-doped fiber laser output characteristics were theoretical analyzed. On the basis of the energy level structure and optical absorption properties of Tm3+ ion, combining with the basic principle of Tm3+-doped fiber laser, and starting from the energy level structures and the cross relaxation processes of Tm3+ ion, the three pumping methods of Tm doped fiber laser (TDF) were analyzed and discussed. The influences of output characteristics by different influence factors were simulated. Based on optimization of the equations, for different fiber lengths, doping concentrations and pumping absorption coefficients and other influence factors, the laser output characteristics under different conditions were obtained and analyzed. Combination the simulation analysis, through the reasonable design and the selection of the optimum parameters of the laser system, the high laser output performance scan be achieved by improving the injection power and controlling of fiber coil diameter. The influences of different factors on the output characteristics were analyzed in the issue. The high laser output performances can be obtained and the laser loss was reduced by selecting the parameters of the laser system properly.

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

    Energy Technology Data Exchange (ETDEWEB)

    Anzueto S, G.; Estudillo A, M. [FIMEE, Campus Salamanca, Universidad de Guanajuato, Domicilio conocido, Comunidad de Palo Blanco, 36885, A.P. 215-A, Salamanca, Guanajuato (Mexico); Martinez R, A.; Torres G, I. [Centro de Investigaciones en Optica, Lomas del Bosque 115, 37150, Leon, Guanajuato (Mexico); Selvas A, R. [Facultad de Ciencias Fisico Matematicas, UANL, Cd. Universitaria, 66450, Nuevo Leon (Mexico)]. e-mail: gilberto.anzueto@gmail. com

    2008-07-01

    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 {approx}2.5 {mu}J was estimated and the repetition rate was measured in the range of 4-16 KHz. (Author)

  8. Fibre Laser At 589nm Using Pr+3 - Doped Fluoride Glass

    Science.gov (United States)

    2007-11-02

    range of Pr-doped fluoride glasses with the aim of identifying a suitable glass host for a 589 nm laser. Pr-doped fluorozirconate ZBLAN glass is known to...F 2 at 635 nm, which both originate from the 3P0 level and therefore compete. In ZBLAN glass the two peaks have equal strength. However, we found...4� Pr3÷ -doped fluoride glass for a 589 nm fibre laser University of Leeds Principal investigator: Dr Animesh Jha Final Report 1 July 1998 - 31

  9. The dawn of computer-assisted robotic osteotomy with ytterbium-doped fiber laser.

    Science.gov (United States)

    Sotsuka, Yohei; Nishimoto, Soh; Tsumano, Tomoko; Kawai, Kenichiro; Ishise, Hisako; Kakibuchi, Masao; Shimokita, Ryo; Yamauchi, Taisuke; Okihara, Shin-ichiro

    2014-05-01

    Currently, laser radiation is used routinely in medical applications. For infrared lasers, bone ablation and the healing process have been reported, but no laser systems are established and applied in clinical bone surgery. Furthermore, industrial laser applications utilize computer and robot assistance; medical laser radiations are still mostly conducted manually nowadays. The purpose of this study was to compare the histological appearance of bone ablation and healing response in rabbit radial bone osteotomy created by surgical saw and ytterbium-doped fiber laser controlled by a computer with use of nitrogen surface cooling spray. An Ytterbium (Yb)-doped fiber laser at a wavelength of 1,070 nm was guided by a computer-aided robotic system, with a spot size of 100 μm at a distance of approximately 80 mm from the surface. The output power of the laser was 60 W at the scanning speed of 20 mm/s scan using continuous wave system with nitrogen spray level 0.5 MPa (energy density, 3.8 × 10(4) W/cm(2)). Rabbits radial bone osteotomy was performed by an Yb-doped fiber laser and a surgical saw. Additionally, histological analyses of the osteotomy site were performed on day 0 and day 21. Yb-doped fiber laser osteotomy revealed a remarkable cutting efficiency. There were little signs of tissue damage to the muscle. Lased specimens have shown no delayed healing compared with the saw osteotomies. Computer-assisted robotic osteotomy with Yb-doped fiber laser was able to perform. In rabbit model, laser-induced osteotomy defects, compared to those by surgical saw, exhibited no delayed healing response.

  10. Accurate potential drop sheet resistance measurements of laser-doped areas in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, Martin, E-mail: mh.seris@gmail.com [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore 117574 (Singapore); NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore 117456 (Singapore); Kluska, Sven; Binder, Sebastian [Fraunhofer Institute for Solar Energy Systems (ISE), Heidenhofstrasse 2, D-79110 Freiburg (Germany); Hameiri, Ziv [The School of Photovoltaic and Renewable Energy Engineering, The University of New South Wales, Sydney NSW 2052 (Australia); Hoex, Bram [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore 117574 (Singapore); Aberle, Armin G. [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore 117574 (Singapore); NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore 117456 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117456 (Singapore)

    2014-10-07

    It is investigated how potential drop sheet resistance measurements of areas formed by laser-assisted doping in crystalline Si wafers are affected by typically occurring experimental factors like sample size, inhomogeneities, surface roughness, or coatings. Measurements are obtained with a collinear four point probe setup and a modified transfer length measurement setup to measure sheet resistances of laser-doped lines. Inhomogeneities in doping depth are observed from scanning electron microscope images and electron beam induced current measurements. It is observed that influences from sample size, inhomogeneities, surface roughness, and coatings can be neglected if certain preconditions are met. Guidelines are given on how to obtain accurate potential drop sheet resistance measurements on laser-doped regions.

  11. Progress in rare-earth-doped nanocrystalline glass-ceramics for laser cooling

    Science.gov (United States)

    Venkata Krishnaiah, Kummara; Ledemi, Yannick; Soares de Lima Filho, Elton; Loranger, Sebastien; Nemova, Galina; Messaddeq, Younes; Kashyap, Raman

    2016-03-01

    Laser cooling with anti-Stokes fluorescencewas predicted by Pringsheim in 1929, but for solids was only demonstrated in 1995. There are many difficulties which have hindered laser assisted cooling, principally the chemical purity of a sample and the availability of suitable hosts. Recent progress has seen the cooled temperature plummet to 93K in Yb:YLF. One of the challenges for laser cooling to become ubiquitous, is incorporating the rare-earthcooling ion in a more easily engineered material, rather than a pure crystalline host. Rare-earth-doped nanocrystalline glass-ceramics were first developed by Wang and Ohwaki for enhanced luminescence and mechanical properties compared to their parent glasses. Our work has focused on creating a nanocrystalline environment for the cooling ion, in an easy to engineer glass. The glasses with composition 30SiO2-15Al2O3-27CdF2-22PbF2-4YF3-2YbF3 (mol%), have been prepared by the conventional melt-quenching technique. By a simple post fabrication thermal treatment, the rare-earth ions are embedded in the crystalline phase within the glass matrix. Nanocrystals with various sizes and rare-earth concentrations have been fabricated and their photoluminescence properties assessed in detail. These materials show close to unity photoluminescence quantum yield (PLQY) when pumped above the band. However, they exhibit strong up-conversion into the blue, characteristic of Tm trace impurity whose presence was confirmed. The purification of the starting materials is underway to reduce the background loss to demonstrate laser cooling. Progress in the development of these nano-glass-ceramics and their experimental characterization will be discussed.

  12. Highly optimized tunable Er3+-doped single longitudinal mode fiber ring laser, experiment and model

    DEFF Research Database (Denmark)

    Poulsen, Christian; Sejka, Milan

    1993-01-01

    A continuous wave (CW) tunable diode-pumped Er3+-doped fiber ring laser, pumped by diode laser at wavelengths around 1480 nm, is discussed. Wavelength tuning range of 42 nm, maximum slope efficiency of 48% and output power of 14.4 mW have been achieved. Single longitudinal mode lasing...

  13. Mode-locked Pr3+-doped silica fiber laser with an external cavity

    DEFF Research Database (Denmark)

    Shi, Yuan; Poulsen, Christian; Sejka, Milan

    1994-01-01

    We present a Pr3+-doped silica-based fiber laser mode-locked by using a linear external cavity with a vibrating mirror. Stable laser pulses with a FWHM of less than 44 ps, peak power greater than 9 W, and repetition rate up to 100 MHz are obtained. The pulse width versus cavity mismatch ΔL and pump...

  14. Optimization of the gain in Yb3+-doped cubic laser crystals of 99.99% purity

    Institute of Scientific and Technical Information of China (English)

    Georges Boulon; Yannick Guyot; Akira Yoshikawa

    2009-01-01

    This was an outlook on the prediction of the infrared laser potentiality from concentration dependences of the 2F5/2 experimental decay time in Yb3+-doped solid-state crystals mainly on cubic crystals with 99.99% purity which could be extended to laser ceramics of the same composition.

  15. Linear polarization Yb3+-doped fiber laser with novel innerclad structures

    NARCIS (Netherlands)

    Martinez-Pinon, F.; Alvarez-Chavez, J.A.; Jaramillo-Vigueras, D.; Cruz-May, de la L.; Offerhaus, H.L.

    2008-01-01

    Results on high radiance Yb3+-doped fiber lasers with novel double innerclad structures (double-D clad and four hole) and polarized output at ≈1090 nm are presented. We have demonstrated >40% of the total output power being polarized, making the fiber laser suitable for LIDAR and second-harmonic gen

  16. Effect of Ultrashort Pulsed Laser and X-Ray Irradiation on Au~+ -Doped Glass

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Au nanoparticles were precipitated inside Au+-doped glass samples after irradiation by femtosecond laser or x-ray. Femtosecond laser and X-ray irradiation result in decreasing of anneal temperature and critical size for the precipitation of Au nanoparticles.

  17. Effect of Ultrashort Pulsed Laser and X-Ray Irradiation on Au+ -Doped Glass

    Institute of Scientific and Technical Information of China (English)

    Huidan Zeng; Jianrong Qiu; Xiongwei Jiang; Congshan Zhu; Fuxi Gan

    2003-01-01

    Au nanoparticles were precipitated inside Au+-doped glass samples after irradiation by femtosecond laser or x-ray. Femtosecond laser and X-ray irradiation result in decreasing of anneal temperature and critical size for the precipitation of Au nanoparticles.

  18. Linear polarization Yb3+-doped fiber laser with novel innerclad structures

    NARCIS (Netherlands)

    Martinez-Pinon, F.; Alvarez-Chavez, J.A.; Jaramillo Vigueras, D.; de la Cruz-May, L.; Offerhaus, Herman L.

    2008-01-01

    Results on high radiance Yb3+-doped fiber lasers with novel double innerclad structures (double-D clad and four hole) and polarized output at ≈1090 nm are presented. We have demonstrated >40% of the total output power being polarized, making the fiber laser suitable for LIDAR and second-harmonic gen

  19. Versatile Chromium-Doped Zinc Selenide Infrared Laser Sources

    Science.gov (United States)

    2010-05-01

    Erbium Doped Fiber Amplifiers ( EDFAs ). An EDFA is essentially a normal optical fiber waveguide that has been lightly doped with a rare-earth...element, namely erbium (possibly co-doped with ytterbium to increase the pumping efficiency and gain). In a typical EDFA , 980 nm photons are used to

  20. Group III-nitride lasers: a materials perspective

    Directory of Open Access Journals (Sweden)

    Matthew T. Hardy

    2011-09-01

    Full Text Available An overview of III-Nitride based laser diodes (LDs is presented focusing on the materials challenges in each phase of device development. We discuss early breakthroughs leading to the first commercial GaN LDs, covering crystal growth, p-type doping, and defect reduction. Additional device issues, such as polarization effects, strain, and index dispersion are addressed as they apply to the development of blue and green LDs for pico-projector applications. State of the art device results are highlighted. Devices grown on non-polar and semi-polar GaN substrates address many polarization related problems present in c-plane GaN growth. Device results, advantages, and limitations of various non-polar and semi-polar systems are discussed in terms of polarization properties, Indium incorporation, extended defect formation, and critical thickness. A brief description of challenges and progress in UV LDs is also presented.

  1. Optical bistability in erbium-doped yttrium aluminum garnet crystal combined with a laser diode.

    Science.gov (United States)

    Maeda, Y

    1994-01-10

    Optical bistability was observed in a simple structure of an injection laser diode combined with an erbium-doped yttrium aluminum garnet crystal. Since a hysteresis characteristic exists in the relationship between the wavelength and the injection current of a laser diode, an optical memory function capable of holding the output status is confirmed. In addition, an optical signal inversion was caused by the decrease of transmission of the erbium-doped yttrium aluminum garnet crystal against the red shift (principally mode hopping) of the laser diode. It is suggested that the switching time of this phenomenon is the time necessary for a mode hopping by current injection.

  2. Ca2+-Doped CeBr3 Scintillating Materials

    Energy Technology Data Exchange (ETDEWEB)

    Guss, Paul [NSTec; Foster, Michael E. [SNL; Wong, Bryan M. [SNL; Doty, F. Patrick [SNL; Shah, Kanai [RMD; Squillante, Michael R. [RMD; Shirwadkar, Urmila [RMD; Hawrami, Rastgo [RMD; Tower, Josh [RMD; Yuan, Ding [NSTec

    2014-01-01

    Despite the outstanding scintillation performance characteristics of cerium tribromide (CeBr3) and cerium-activated lanthanum tribromide, their commercial availability and application are limited due to the difficulties of growing large, crack-free single crystals from these fragile materials. This investigation employed aliovalent doping to increase crystal strength while maintaining the optical properties of the crystal. One divalent dopant (Ca2+) was used as a dopant to strengthen CeBr3 without negatively impacting scintillation performance. Ingots containing nominal concentrations of 1.9% of the Ca2+ dopant were grown. Preliminary scintillation measurements are presented for this aliovalently doped scintillator. Ca2+-doped CeBr3 exhibited little or no change in the peak fluorescence emission for 371 nm optical excitation for CeBr3. The structural, electronic, and optical properties of CeBr3 crystals were studied using the density functional theory within the generalized gradient approximation. The calculated lattice parameters are in good agreement with the experimental data. The energy band structures and density of states were obtained. The optical properties of CeBr3, including the dielectric function, were calculated.

  3. Black phosphorus based saturable absorber for Nd-ion doped pulsed solid state laser operation

    Science.gov (United States)

    Han, S.; Zhang, F.; Wang, M.; Wang, L.; Zhou, Y.; Wang, Z.; Xu, X.

    2016-12-01

    In this paper, the use of black phosphorus (BP) as a saturable absorber in a Q-switched Nd-ion doped solid state laser is presented. Few layers of BP in isopropyl alcohol are obtained by liquid phase exfoliation. The BP nanosheets with thicknesses in the range of 15-20 nm are deposited onto a K9 glass substrate. By inserting the BP nanosheets into a diode pumped Nd-ion doped solid state laser, stable Q-switched lasing at 0.9, 1.06, 1.3 μm is obtained. Using this approach, we have achieved a short pulse duration down to 219 ns, a high pulse energy of up to 6.5 μJ, and the corresponding peak power of 30 W. Our results show that the BP saturable absorber functions well in a Nd-ion doped solid state laser for pulsed laser generation.

  4. 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.

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

    Science.gov (United States)

    Feng, Tianxian; Mao, Dong; Cui, Xiaoqi; Li, Mingkun; Song, Kun; Jiang, Biqiang; Lu, Hua; Quan, Wangmin

    2016-11-11

    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.

  6. Laser ablation of a polysilane material

    Science.gov (United States)

    Hansen, S. G.; Robitaille, T. E.

    1987-08-01

    The laser ablation properties of a (50%)-isopropyl methyl-(50%)-n-propyl methyl silane copolymer are examined. Both 193- and 248-nm-pulsed excimer laser radiation cleanly and completely remove this material in vacuum above certain energy thresholds (30 and 50 mJ/cm2, respectively). Under these conditions the ablation properties are quite similar to those reported for typical organic polymers. Below threshold, ablation is less efficient and becomes increasingly inefficient as irradiation continues due to spectral bleaching. In the presence of air, material removal is incomplete even for high-energy densities and long exposures. The ablation rate is shown to be independent of substrate material both above and below threshold.

  7. Direct laser writing of topographic features in semiconductor-doped glass

    Science.gov (United States)

    Smuk, Andrei Y.

    2000-11-01

    Patterning of glass and silica surfaces is important for a number of modern technologies, which depend on these materials for manufacturing of both final products, such as optics, and prototypes for casting and molding. Among the fields that require glass processing on microscopic scale are optics (lenses and arrays, diffractive/holographic elements, waveguides), biotechnology (capillary electrophoresis chips and biochemical libraries) and magnetic media (landing zones for magnetic heads). Currently, standard non-laser techniques for glass surface patterning require complex multi-step processes, such as photolithography. Work carried out at Brown has shown that semiconductor- doped glasses (SDG) allow a single-step patterning process using low power continuous-wave visible lasers. SDG are composite materials, which consist of semiconductor crystallites embedded into glass matrix. In this study, borosilicate glasses doped with CdSxSe1-x nanocrystals were used. Exposure of these materials to a low-power above- the-energy gap laser beam leads to local softening, and subsequent expansion and rapid solidification of the exposed volume, resulting in a nearly spherical topographic feature on the surface. The effects of the incident power, beam configuration, and the exposure time on the formation and final parameters of the microlens were studied. Based on the numerical simulation of the temperature distribution produced by the absorbed Gaussian beam, and the ideas of viscous flow at the temperatures around the glass transition point, a model of lens formation is suggested. The light intensity distribution in the near-field of the growing lens is shown to have a significant effect on the final lens height. Fabrication of dense arrays of microlenses is shown, and the thermal and structural interactions between the neighboring lenses were also studied. Two-dimensional continuous-profile topographic features are achieved by exposure of the moving substrates to the writing

  8. Electrical characterization of gadolinia doped ceria films grown by pulsed laser deposition

    DEFF Research Database (Denmark)

    Rodrigo, Katarzyna Agnieszka; Heiroth, Sebastian; Lundberg, Mats

    2010-01-01

    Electrical characterization of 10 mol% gadolinia doped ceria (CGO10) films of different thicknesses prepared on MgO(100) substrates by pulsed laser deposition is presented. Dense, polycrystalline and textured films characterized by fine grains (grain sizes ... thickness. The conductivity of the nanocrystalline films is lower (7.0×10−4 S/cm for the 20-nm film and 3.6×10−3 S/cm for the 435-nm film, both at 500°C) than that of microcrystalline, bulk samples ( S/cm at 500°C). The activation energy for the conduction is found to be 0.83 eV for the bulk material, while...

  9. Laser refrigeration of rare-earth doped sodium-yttrium-fluoride nanowires

    Science.gov (United States)

    Zhou, Xuezhe; Roder, Paden B.; Smith, Bennett E.; Pauzauskie, Peter J.

    2017-02-01

    Hexagonal sodium yttrium fluoride (β-NaYF4) crystals are currently being studied for a wide range of applications including color displays, solar cells, photocatalysis, and bio-imagβing. β-NaYF4 has also been predicted to be a promising host material for laser refrigeration of solids. However, due to challenges with growing Czochralski β- NaYF4 single-crystals, laser refrigeration of bulk β-NaYF4 has not yet been achieved6. Recently hydrothermal processing has been reported to produce Yb-doped β-NaYF4 nanowires (NWs) that undergo laser refrigeration during single-beam optical trapping experiments in heavy water. The local refrigeration of the individual nanowire is quantified through the analysis of its Brownian motion through the analysis of forward scattered light that is focused onto a quadrant photodiode. The individual β-NaYF4 nanowires show maximum local cooling of 9°C below ambient conditions. Here we present the emission lifetime for the 4S3/2 - 4I15/2 transition for Er(III) ions in Yb/Er-codoped -NaYF4 NW ensembles was measured to be (220 +/- 6) μs using a an electron multiplying charge coupled device (EMCCD) as a detector with high spatial resolution. This lifetime is consistent with values reported in the literature.

  10. Mechanism of Spatiotemporal Distribution of Laser Ablated Materials

    Institute of Scientific and Technical Information of China (English)

    XU Rong-Qing; CUI Yi-Ping; LU Jian; NI Xiao-Wu

    2009-01-01

    Interaction between subsequent laser and ablated materials in laser processing changes the laser spatiotemporal distribution and has influences on the efficiency and quality of laser processing. The theoretical and experimental researches on transportation behayiour of ablated materials are provided. It is shown that the velocity distribution of ablated materials is determined by ablation mechanism. The transportation behaviour of ablated materials is controlled by diffusion mechanism and light field force during laser pulse duration while it is only determined by diffusion mechanism when the laser pulse terminates. In addition, the spatiotemporal distribution of ablated materials is presented.

  11. Laser-Doping through Anodic Aluminium Oxide Layers for Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Pei Hsuan Doris Lu

    2015-01-01

    Full Text Available This paper demonstrates that silicon can be locally doped with aluminium to form localised p+ surface regions by laser-doping through anodic aluminium oxide (AAO layers formed on the silicon surface. The resulting p+ regions can extend more than 10 μm into the silicon and the electrically active p-type dopant concentration exceeds 1020 cm−3 for the first 6-7 μm of the formed p+ region. Anodic aluminium oxide layers can be doped with other impurities, such as boron and phosphorus, by anodising in electrolytes containing the extrinsic impurities in ionic form. The ions become trapped in the formed anodic oxide during anodisation, therefore enabling the impurity to be introduced into the silicon, with aluminium, during laser-doping. This codoping process can be used to create very heavily doped surface layers which can reduce contact resistance on metallisation, whilst the deeper doping achieved by the intrinsic aluminium may act to shield the surface from minority carriers. laser-doping through AAO layers can be performed without introducing any voids in the silicon or fumes which may be harmful to human health.

  12. Using Si-doped diamond plate of sandwich type for spatial profiling of laser beam

    Science.gov (United States)

    Shershulin, V. A.; Samoylenko, S. R.; Sedov, V. S.; Kudryavtsev, O. S.; Ralchenko, V. G.; Nozhkina, A. V.; Vlasov, I. I.; Konov, V. I.

    2017-02-01

    We demonstrated a laser beam profiling method based on imaging of the laser induced photoluminescence of a transparent single-crystal diamond plate. The luminescence at 738 nm is caused by silicon-vacancy color centers formed in the epitaxial diamond film by its doping with Si during CVD growth of the film. The on-line beam monitor was tested for a cw laser emitting at 660 nm wavelength.

  13. Dispersion-managed dark solitons in erbium-doped fiber lasers

    OpenAIRE

    Zhang, Han; Tang, Dingyuan; Tlidi, Mustapha; Zhao, Luming; Wu,Xuan

    2010-01-01

    We report on the observation of dispersion-managed (DM) dark soliton emission in a net-normal dispersion erbium-doped fiber laser. We found experimentally that dispersion management could not only reduce the pump threshold for the dark soliton formation in a fiber laser, but also stabilize the single dark soliton evolution in the cavity. Numerical simulations have also confirmed the DM dark soliton formation in a fiber laser.

  14. Er-doped fiber ring laser gyroscopes operating in continuous waves

    Institute of Scientific and Technical Information of China (English)

    Jingren Qian; Jue Su; Xuxu Wang; Bing Zhu

    2007-01-01

    A direction related polarizer was inserted into a ring laser cavity to eliminate one of the two eigen-modes as well as spatial hole burning of the gain medium in a bidirectional Er-doped fiber ring laser. Thus, a fiber ring laser gyroscope (FRLG) operating in continuous wave was demonstrated. A beat signal of over 30-dB noise was observed and a good inear relation between the beat frequency shift and cavity rotation rate was obtained.

  15. Picosecond laser bonding of highly dissimilar materials

    Science.gov (United States)

    Carter, Richard M.; Troughton, Michael; Chen, Jianyong; Elder, Ian; Thomson, Robert R.; Lamb, Robert A.; Esser, M. J. Daniel; Hand, Duncan P.

    2016-10-01

    We report on recent progress in developing an industrially relevant, robust technique to bond dissimilar materials through ultra-fast microwelding. This technique is based on the use of a 5.9ps, 400kHz Trumpf laser operating at 1030nm. Tight focusing of the laser radiation at, or around, the interface between two materials allows for simultaneous absorption in both. This absorption rapidly, and locally, heats the material forming plasma from both materials. With suitable surface preparation this plasma can be confined to the interface region where it mixes, cools and forms a weld between the two materials. The use of ps pulses results in a short interaction time. This enables a bond to form whilst limiting the heat affected zone (HAZ) to a region of only a few hundred micrometres across. This small scale allows for the bonding of materials with highly dissimilar thermal properties, and in particular coefficients of thermal expansion e.g. glass-metal bonding. We report on our results for a range of material combinations including, Al-Bk7, Al-SiO2 and Nd:YAG-AlSi. Emphasis will be laid on the technical requirements for bonding including the required surface preparation of the two materials and on the laser parameters required. The quality of the resultant bonds are characterized through shear force measurements (where strengths equal to and exceeding equivalent adhesives will be presented). The lifetime of the welds is also discussed, paying particular attention to the results of thermal cycling tests.

  16. Generation of a 650 nm - 2000 nm Laser Frequency Comb based on an Erbium-Doped Fiber Laser

    CERN Document Server

    Ycas, Gabriel; Diddams, Scott A

    2012-01-01

    We present a laser frequency comb based upon a 250 MHz mode-locked erbium-doped fiber laser that spans more than 300 terahertz of bandwidth, from 660 nm to 2000 nm. The system generates 1.2 nJ, 70 fs pulses at 1050 nm by amplifying the 1580 nm laser light in Er:fiber, followed by nonlinear broadening to 1050 nm and amplification in Yb:fiber. Extension of the frequency comb into the visible is achieved by supercontinuum generation from the 1050 nm light. Comb coherence is verified with cascaded f-2f interferometry and comparison to a frequency stabilized laser.

  17. Spectroscopic analyses of trivalent rare-earth ions doped in different host materials

    Science.gov (United States)

    Chandrasekharan, Sreerenjini

    2011-12-01

    Trivalent rare-earth (RE3+) ions of 4f n electronic configurations are found to possess potential applications in the field of optoelectronic and biophotonic technologies owing to their unique optical properties. They have been used as optical activators in a large number of solid-state laser host materials due to their rich energy level structure. This work focuses on the spectroscopic study of two RE 3+ ions, namely, trivalent erbium and neodymium (Er3+ and Nd3+, respectively), embedded in some important single crystal and nanocrystalline host materials including yttrium orthoaluminate (YAlO3), erbium oxide (Er2O3), yttrium oxide (Y2O3) and a combined host system of Y2O 3 and a vinyl polymer named Polymethyl Methacrylate (PMMA). Each one of these host materials are known to be unique for their characteristic properties such as chemical durability, thermal stability, optical clarity, wide band gaps, biocompatibility, and success as phosphors in various optoelectronic devices. The complete material characterization has been performed through morphology analyses using advanced microscopy techniques and spectroscopic analyses of the characteristic absorption and emission spectra by applying phenomenological crystal-field splitting and Judd-Ofelt techniques. The important spectroscopic parameters such as line strengths, radiative decay rates, and branching ratios have been obtained for the intermanifold transitions from the upper multiplets to the corresponding lower-lying multiplet manifolds 2S+1LJ of RE3+ ions doped in various host systems. Using the radiative decay rates, radiative life times are obtained and the experimental analyses of the fluorescent spectra yield the measured lifetimes of emitting metastable states. Finally, the results are compared with the previously published set of values for the same ions doped in similar type of host systems. Detailed analyses of the spectroscopic properties show that the studied systems RE3+ doped single crystals and

  18. Short Tm3+-doped fiber lasers with watt-level output near 2 μm

    Institute of Scientific and Technical Information of China (English)

    Yulong Tang; Yong Yang; Xiaojin Cheng; Jianqiu Xu

    2008-01-01

    High-power operation of diode-pumped fiber lasers at wavelength near 2μm are demonstrated with short length of heavily Tm3+-doped silica glass fibers. With 7-cm long fiber, a laser at near 2 μm is obtained with the threshold of 135 mW, maximum output power of 1.09 W, and slope efficiency of 9.6% with respect to the launched power from a laser diode at 790 nm. The output stability of this fiber laser is within 5%.The dependence of the performance of fiber lasers on the operation temperature and cavity configuration parameters is also investigated.

  19. Single-frequency, single-polarization ytterbium-doped fiber laser by self-injection locking

    Institute of Scientific and Technical Information of China (English)

    Anting Wang(王安廷); Hai Ming(明海); Feng Li(李锋); Lixin Xu(许立新); Liang Lü(吕亮); Huaqiao Gui(桂华侨); Jing Huang(黄晶); Jianping Xie(谢建平)

    2004-01-01

    We demonstrated a stable single-frequency, single-polarization operation of ytterbium-doped fiber laser. As a novel practical method to realize single-polarization operation of fiber distributed Bragg reflector (DBR)laser, we proposed self-injection locking (SIL) with an active fiber ring feedback cavity. The laser has high output power exceeding 15 mW, wavelength of 1053.20 nm, and side-mode suppression ratio greater than 60 dB. The SIL fiber laser shows the improvements in output power and side-mode suppression compared with the fiber DBR laser. No mode-hopping is observed within 2 hours.

  20. Dynamics of an erbium-doped fiber laser with pump modulation: theory and experiment

    Science.gov (United States)

    Pisarchik, Alexander N.; Kir'yanov, Alexander V.; Barmenkov, Yuri O.; Jaimes-Reátegui, Rider

    2005-10-01

    We study in detail the complex dynamics of an erbium-doped fiber laser that has been subjected to harmonic modulation of a diode pump laser. We introduce a novel laser model that describes perfectly all experimentally observed features. The model is generalized to a nonlinear oscillator. The coexistence of different periodic and chaotic regimes and their relation to subharmonics and higher harmonics of the relaxation oscillation frequency of the laser are demonstrated with codimensional-one and codimensional-two bifurcation diagrams in parameter space of the modulation frequency and amplitude. The phase difference between the laser response and the pump modulation is also investigated.

  1. Synthesis of phthalocyanine doped sol-gel materials

    Science.gov (United States)

    Dunn, Bruce

    1993-01-01

    The synthesis of sol-gel silica materials doped with three different types of metallophthalocyanines has been studied. Homogeneous materials of good optical quality were prepared and the first optical limiting measurements of dyes in sol-gel hosts were carried out. The properties of these solid state limiters are similar to limiters based on phthalocyanine (Pc) in solution. Sol-gel silica materials containing copper, tin and germanium phthalocyanines were investigated. The initial step in all cases was to prepare silica sols by the sonogel method using tetramethoxy silane (TMOS), HCl and distilled water. Thereafter, the synthesis depended upon the specific Pc and its solubility characteristics. Copper phthalocyanine tetrasulfonic acid tetra sodium salt (CuPc4S) is soluble in water and various doping levels (1 x 10 (exp -4) M to 1 x 10 (exp -5) M) were added to the sol. The group IV Pc's, SnPc(OSi(n-hexyl)3)2 and GePc(OSi(n-hexyl)3)2, are insoluble in water and the process was changed accordingly. In these cases, the compounds were dissolved in THF and then added to the sol. The Pc concentration in the sol was 2 x 10(exp -5)M. The samples were then aged and dried in the standard method of making xerogel monoliths. Comparative nanosecond optical limiting experiments were performed on silica xerogels that were doped with the different metallophthalocyanines. The ratio of the net excited state absorption cross section (sigma(sub e)) to the ground state cross section (sigma(sub g)) is an important figure of merit that is used to characterize these materials. By this standard the SnPc sample exhibits the best limiting for the Pc doped sol-gel materials. Its cross section ratio of 19 compares favorably with the value of 22 that was measured in toluene. The GePc materials appear to not be as useful as those containing SnPc. The GePc doped solids exhibit a higher onset energy (2.5 mj and lower cross section ratio, 7. The CuPc4S sol-gel material has a still lower cross

  2. Emitter formation using laser doping technique on n- and p-type c-Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    López, G., E-mail: gema.lopez@upc.edu; Ortega, P.; Colina, M.; Voz, C.; Martín, I.; Morales-Vilches, A.; Orpella, A.; Alcubilla, R.

    2015-05-01

    Highlights: • We use laser doping technique to create highly-doped regions. • Dielectric layers are used as both passivating layer and dopant source. • The high quality of the junctions makes laser doping technique using dielectric layers as dopant source suitable for solar cells applications. - Abstract: In this work laser doping technique is used to create highly-doped regions defined in a point-like structure to form n+/p and p+/n junctions applying a pulsed Nd-YAG 1064 nm laser in the nanosecond regime. In particular, phosphorous-doped silicon carbide stacks (a-SiC{sub x}/a-Si:H (n-type)) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) and aluminum oxide (Al{sub 2}O{sub 3}) layers deposited by atomic layer deposition (ALD) on 2 ± 0.5 Ω cm p- and n-type FZ c-Si substrates respectively are used as dopant sources. Laser power and number of pulses per spot are explored to obtain the optimal electrical behavior of the formed junctions. To assess the quality of the p+ and n+ regions, the junctions are electrically contacted and characterized by means of dark J–V measurements. Additionally, a diluted HF treatment previous to front metallization has been explored in order to know its impact on the junction quality. The results show that fine tuning of the energy pulse is critical while the number of pulses has minor effect. In general the different HF treatments have no impact in the diode electrical behavior except for an increase of the leakage current in n+/p junctions. The high electrical quality of the junctions makes laser doping, using dielectric layers as dopant source, suitable for solar cell applications. Particularly, a potential open circuit voltage of 0.64 V (1 sun) is expected for a finished solar cell.

  3. Cavity-enhanced laser cooling of solid-state materials in a standing-wave cavity

    Institute of Scientific and Technical Information of China (English)

    Youhua Jia; Biao Zhong; Jianping Yin

    2008-01-01

    We propose a new method to cool the Yba+-doped ZBLANP glass in a standing-wave cavity. There are two advantages of this cavity-enhanced technique: the pumping power is greatly enhanced and the absorption of the cooling material is greatly increased. We introduce the basic principle of the cavity-enhanced laser cooling and discuss the cooling effect of a solid-state material in a cavity. From the theoretical study, it is found that the laser cooling effect is strongly dependent on the reflectivity of the cavity mirrors, the length of the solid material, the surface scattering of the material, and so on. Some optimal parameters for efficient laser cooling are obtained.

  4. Comparison of ion exchange and cw CO2 laser treatment of Nd-doped phosphate laser glass

    Science.gov (United States)

    Hui, Gong; Chengfu, Li

    1996-05-01

    In recent years, the effect of laser pre-irradiation and ion exchange on glasses surface were widely carried out to stabilize their damage thresholds. But comparison of ion exchange and CW CO2 laser treatment is never studied, this paper is devoted to the investigation of this question. Nd-doped phosphate laser glasses were heated with CW CO2 laser radiation and were strengthened by ion exchange. Laser damage thresholds of the surface were measured with 1064 nm 10 ns pulses focused to small spots irradiation. Both ion exchange treatment and CW CO2 laser treatment result in residual compress stress occurred at surface, peak-to- volley and microcracks decreased in surface appearance, and damage thresholds of surfaces increased by a factor of over 2. Polariscope, reflected optical microscope and atomic force microscope are used for stress, damage morphologies and surface topography analysis on glass surface. It is shown that laser condition mechanism is consistent with ion exchange treatment mechanism.

  5. In-volume waveguides by fs-laser direct writing in rare-earth-doped fluoride glass and phosphate glass

    Science.gov (United States)

    Esser, D.; Wortmann, D.; Gottmann, J.

    2009-02-01

    Refractive index modifications are fabricated in the volume of rare-earth-doped glass materials namely Er- and Pr-doped ZBLAN (a fluoride glass consisting of ZrF4, BaF2, LaF3, AlF3, NaF), an Er-doped nano-crystalline glass-ceramic and Yb- and Er-doped phosphate glass IOG. Femtosecond laser radiation (τ=500fs, λ=1045nm, f=0.1-5MHz) from an Ybfiber laser is focused with a microscope objective in the volume of the glass materials and scanned below the surface with different scan velocities and pulse energies. Non-linear absorption processes like multiphoton- and avalanche absorption lead to localized density changes and the formation of color centers. The refractive index change is localized to the focal volume of the laser radiation and therefore, a precise control of the modified volume is possible. The width of the written structures is analyzed by transmission light microscopy and additionally with the quantitative phase microscopy (QPm) software to determine the refractive index distribution perpendicular to a waveguide. Structures larger than 50μm in width are generated at high repetition rates due to heat accumulation effects. In addition, the fabricated waveguides are investigated by far-field measurements of the guided light to determine their numerical apertures. Using interference microscopy the refractive index distribution of waveguide cross-sections in phosphate glass IOG is determined. Several regions with an alternating refractive index change are observed whose size depend on the applied pulse energies and scan velocities.

  6. Ultrafast laser spectroscopy in complex solid state materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tianqi [Iowa State Univ., Ames, IA (United States)

    2014-12-01

    This thesis summarizes my work on applying the ultrafast laser spectroscopy to the complex solid state materials. It shows that the ultrafast laser pulse can coherently control the material properties in the femtosecond time scale. And the ultrafast laser spectroscopy can be employed as a dynamical method for revealing the fundamental physical problems in the complex material systems.

  7. Rare-earth-ion-doped ultra-narrow-linewidth lasers on a silicon chip and applications to intra-laser-cavity optical sensing

    NARCIS (Netherlands)

    Bernhardi, Edward; de Ridder, R.M.; Worhoff, Kerstin; Pollnau, Markus

    We report on diode-pumped distributed-feedback (DFB) and distributed-Bragg-reflector (DBR) channel waveguide lasers in Er-doped and Yb-doped Al2O3 on standard thermally oxidized silicon substrates. Uniform surface-relief Bragg gratings were patterned by laser-interference lithography and etched into

  8. Rare-earth-ion-doped ultra-narrow-linewidth lasers on a silicon chip and applications to intra-laser-cavity optical sensing

    NARCIS (Netherlands)

    Bernhardi, E.H.; Ridder, de R.M.; Wörhoff, K.; Pollnau, M.

    2013-01-01

    We report on diode-pumped distributed-feedback (DFB) and distributed-Bragg-reflector (DBR) channel waveguide lasers in Er-doped and Yb-doped Al2O3 on standard thermally oxidized silicon substrates. Uniform surface-relief Bragg gratings were patterned by laser-interference lithography and etched into

  9. Passively Q-switched and mode-locked erbium doped fiber laser based on N-doped graphene saturable absorber

    Science.gov (United States)

    Ahmad, H.; Aidit, S. N.; Ooi, S. I.; Rezayi, M.; Tiu, Z. C.

    2017-10-01

    A passively Q-switched and mode-locked erbium-doped fiber laser based on a nitrogen-doped graphene saturable absorber is demonstrated. The N-doped graphene based saturable absorber has a modulation depth of 37.88% and a saturation intensity of 0.016 73 MW cm‑2. By integrating the N-doped graphene saturable absorber into the laser cavity, a stable Q-switched operation with a centre wavelength of 1561.1 nm is obtained with a pulse energy of up to 29.0 nJ. As the pump power increases, the Q-switching operation transits into a mode-locking operation. The mode-locking operation is achieved with a centre wavelength of 1560 nm, a pulse width of 0.98 ps, a repetition rate of 28.5 MHz and a signal to noise ratio of up to 40 dB in the RF spectrum.

  10. Absorption of some powder materials to YAG laser

    Institute of Scientific and Technical Information of China (English)

    SHAOT.M.; LINX.C.; ZHOUM.

    2001-01-01

    Laser powder alloying is widely used for tribological applications. As one of the key pa-rameters , absorptivity of powder materials to laser plays an important role in the processing. Themeasurement of laser absorptivity is essential for absorptivity research. In present work, lumpedmethod based on heat transfer is established for laser absorptivity measurement. The absorptivityof some powder materials as Cu, Fe, Al, NiO, Al2O3, ZrO2, SiC, to YAG laser, are investigated.The results show that the absorptivity of powder materials to YAG laser is generally larger thanthat of bulk materials.

  11. Pulsed laser deposited Al-doped ZnO thin films for optical applications

    Directory of Open Access Journals (Sweden)

    Gurpreet Kaur

    2015-02-01

    Full Text Available Highly transparent and conducting Al-doped ZnO (Al:ZnO thin films were grown on glass substrates using pulsed laser deposition technique. The profound effect of film thickness on the structural, optical and electrical properties of Al:ZnO thin films was observed. The X-ray diffraction depicts c-axis, plane (002 oriented thin films with hexagonal wurtzite crystal structure. Al-doping in ZnO introduces a compressive stress in the films which increase with the film thickness. AFM images reveal the columnar grain formation with low surface roughness. The versatile optical properties of Al:ZnO thin films are important for applications such as transparent electromagnetic interference (EMI shielding materials and solar cells. The obtained optical band gap (3.2–3.08 eV was found to be less than pure ZnO (3.37 eV films. The lowering in the band gap in Al:ZnO thin films could be attributed to band edge bending phenomena. The photoluminescence spectra gives sharp visible emission peaks, enables Al:ZnO thin films for light emitting devices (LEDs applications. The current–voltage (I–V measurements show the ohmic behavior of the films with resistivity (ρ~10−3 Ω cm.

  12. CONTROL OF LASER RADIATION PARAMETERS: Passive laser Q switches made of glass doped with oxidised nanoparticles of copper selenide

    Science.gov (United States)

    Yumashev, K. V.

    2000-01-01

    Passive Q switching of Nd3+:YAG (λ = 1060 nm) and YAlO3:Nd3+ (1340 nm) lasers, as well as of an Er3+ (1540 nm) glass laser was realised by using glass doped with oxidised nanoparticles of copper selenide. Nonlinear optical properties of the nanoparticles (radius of 25 nm) in a glass matrix were studied by the picosecond absorption spectroscopy technique.

  13. Pulsed Nd: YAG laser drilling of aerospace materials (Ti-6Al-4V)

    Science.gov (United States)

    Bahar, N. D.; Marimuthu, S.; Yahya, W. J.

    2016-10-01

    This paper studies the influence of Nd:YAG (neodymium-doped yttrium aluminium garnet) laser process parameters on laser drilled hole quality. Ti-6Al-4V of 1 mm and 3 mm thickness were used as the workpiece substrate. The principal findings are mainly based on minimising the taper angle in laser drilled holes, reducing the heat affected zone and reducing the production of spatter. Identification of key process variables associated with laser drilling process is accomplished by trial experimentation. Using the identified key process variables, further experiments were then performed with the assistance of statistical design of experiment (DOE) to find the interaction and individual effects of various laser process parameters on laser drilled hole quality. The lowest taper angle of 1.8 degrees was achieved with use of nitrogen as the assist gas. Furthermore, from the laser process observations, it was found that laser power significantly affects the quality of the laser drilled hole. Increase in laser power would increase the hole size and result in more spatter on the entry hole surfaces. The nozzle focus position substantially influenced the laser drilled hole size. The amount of spatter deposits increased with decrease in the nozzle offset. Increase in laser frequency significantly increased the exit diameter, which resulted in smaller taper angle. Number of pulse required to drill through a workpiece depends on the material properties and physical properties of the material. For 1mm Ti-6Al-4V, a minimum of two pulses was required to successfully removed the material during drilling and a minimum of 4 pulses was required to drill through the same material with 3mm thickness.

  14. The generation of Q-switched erbium-doped fiber laser using black phosphorus saturable absorber with 8% modulation depth

    Science.gov (United States)

    Fauziah, C. M.; Rosol, A. H. A.; Latiff, A. A.; Harun, S. W.

    2017-06-01

    We report a generation of the Q-switched laser operating in 1.55-micron region by using black phosphorus (BP) as a saturable absorber (SA). A 980-nm laser diode was pumped into Erbium-doped fiber (EDF) gain medium in ring cavity configuration. The BP-based SA was prepared by mechanically exfoliating the BP crystal using scotch tape. The obtained BP-tape SA has a modulation depth of 8 %. To realize a Q-switching operation, a small piece of the tape is then integrated into between two fiber ferrule tips. A stable Q-switching operation started at 40 mW. The maximum repetition rate obtainable at 28.57 kHz, with pulse width of 5.35 μs. This finding shows the BP is one of the promising material to work as an SA for pulsed laser generation.

  15. Design and analysis of doped left-handed materials

    Institute of Scientific and Technical Information of China (English)

    Zhang Hong-Xin; Bao Yong-Fang; Lü Ying-Hua; Chen Tian-Ming; Wang Hai-Xia

    2008-01-01

    We devise three sorts of doped left-handed materials (DLHMs) by introducing inductors and capacitors into the traditional left-handed material (LHM) as heterogeneous elements.Some new properties are presented through finitedifference time-domain (FDTD) simulations.On the one hand,the resonance in the traditional LHM is weakened and the original pass band is narrowed by introducing inductors.On the other hand,the original pass band of the LHM can be shifted and a new pass band can be generated by introducing capacitors.When capacitors and inductors are introduced simultaneously,the resonance of traditional LHM is somewhat weakened and the number of original pass bands as well as its bandwidth can be changed.

  16. Stability of short, single-mode erbium-doped fiber lasers

    Energy Technology Data Exchange (ETDEWEB)

    Svalgaard, M.; Gilbert, S.L. [National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80303 (United States)

    1997-07-01

    We conducted a detailed study of the stability of short, erbium-doped fiber lasers fabricated with two UV-induced Bragg gratings written into the doped fiber. We find that the relative intensity noise of single-longitudinal-mode fiber grating lasers is approximately 3 orders of magnitude lower than that of a single-frequency 1.523-{mu}m helium-neon laser. The frequency noise spectrum contains few resonances, none of which exceeds 0.6 kHz/Hz{sup 1/2} rms; the integrated rms frequency noise from 50 Hz to 63 kHz is 36 kHz. We also demonstrate a simple method for monitoring the laser power and number of oscillating modes during laser fabrication. {copyright} 1997 Optical Society of America

  17. Laser materials based on transition metal ions

    Science.gov (United States)

    Moncorgé, Richard

    2017-01-01

    The purpose of this presentation is to review the spectroscopic properties of the main laser materials based on transition metal ions which lead to noticeable laser performance at room temperature and, for very few cases, because of unique properties, when they are operated at cryogenic temperatures. The description also includes the materials which are currently being used as saturable absorbers for passive-Q-switching of a variety of other near- and mid-infrared solid state lasers. A substantial part of the article is devoted first to the description of the energy levels and of the absorption and emission transitions of the transition metal ions in various types of environments by using the well-known Tanabe-Sugano diagrams. It is shown in particular how these diagrams can be used along with other theoretical considerations to understand and describe the spectroscopic properties of ions sitting in crystal field environments of near-octahedral or near-tetrahedral symmetry. The second part is then dedicated to the description (positions and intensities) of the main absorption and emission features which characterize the different types of materials.

  18. Numerical analysis of multiwavelength erbium-doped fiber ring laser exploiting four-wave mixing.

    Science.gov (United States)

    Xu, Xiaochuan; Yao, Yong; Chen, Deying

    2008-08-04

    In this paper, a model is proposed to study the behavior of four-wave mixing assisted multiwavelength erbium doped fiber ring laser based on the theoretical model of the multiple FWM processes and Gile's theory of erbium-doped fiber. It is demonstrated that the mode competition can be effectively suppressed through FWM. The effect of phase matching, the nonlinear coefficient, the power in the cavity and the length of the nonlinear medium on output spectrum uniformity are also investigated.

  19. Dy{sup 3+}-doped Ga–Sb–S chalcogenide glasses for mid-infrared lasers

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Mingjie [Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, Jiangsu 221116 (China); Yang, Anping, E-mail: apyang@jsnu.edu.cn [Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, Jiangsu 221116 (China); Peng, Yuefeng [Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Zhang, Bin; Ren, He; Guo, Wei; Yang, Yan; Zhai, Chengcheng; Wang, Yuwei; Yang, Zhiyong; Tang, Dingyuan [Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, Jiangsu 221116 (China)

    2015-10-15

    Highlights: • Novel Ga–Sb–S chalcogenide glasses doped with Dy{sup 3+} ions were synthesized. • The glasses show good thermal stability and excellent infrared transparency. • The glasses show low phonon energy and intense mid-infrared emissions. • The mid-infrared emissions have high quantum efficiency. • The mid-infrared emissions have large stimulated emission cross sections. - Abstract: Novel Ga–Sb–S chalcogenide glasses doped with different amount of Dy{sup 3+} ions were prepared. Their thermal stability, optical properties, and mid-infrared (MIR) emission properties were investigated. The glasses show good thermal stability, excellent infrared transparency, very low phonon energy (∼306 cm{sup −1}), and intense emissions centered at 2.95, 3.59, 4.17 and 4.40 μm. Three Judd–Ofelt intensity parameters (Ω{sub 2} = 8.51 × 10{sup −20} cm{sup 2}, Ω{sub 4} = 2.09 × 10{sup −20} cm{sup 2}, and Ω{sub 6} = 1.60 × 10{sup −20} cm{sup 2}) are obtained, and the related radiative transition properties are evaluated. The high quantum efficiencies and large stimulated emission cross sections of the MIR emissions (88.10% and 1.11 × 10{sup −20} cm{sup 2} for 2.95 μm emission, 75.90% and 0.38 × 10{sup −20} cm{sup 2} for 4.40 μm emission, respectively) in the Dy{sup 3+}-doped Ga–Sb–S glasses make them promising gain materials for the MIR lasers.

  20. yb3+-Doped Double-Clad Fibre Laser Pumped by Rectangular Inner Cladding

    Institute of Scientific and Technical Information of China (English)

    宁鼎; 李乙刚; 黄榜才; 孙建军; 吕可诚; 袁树忠; 董孝义

    2001-01-01

    A novel Yb3+-doped double-clad silica fibre with rectangular inner cladding was designed and developed by using the modified chemical vapour deposition process, solution-doping and optical machining all together. The dimensions of the inner cladding are 100 × 70 μm, and Yb3+-doped concentration in the core is about 0.24 wt. %. The operation of the fibre laser pumped by inner cladding is reported. The threshold of the laser is 34mW.When the pump power launched is 141mW, the laser output is 84mW at the wavelength 1075.6nm, and the slope efficiency is 77%.

  1. Breaking the low phonon energy barrier for laser cooling in rare-earth doped hosts

    Science.gov (United States)

    Nemova, Galina; Kashyap, Raman

    2011-03-01

    A new approach to cool rare earth doped solids with optical super-radiance (SR) is presented. SR is the coherent, sharply directed spontaneous emission of photons by a system excited with a pulsed laser. We consider an Yb3+ doped ZBLAN sample pumped at the wavelength 1015nm with a rectangular pulsed source with a power of ~700W and duration of 20ns. The intensity of the SR is proportional to the square of the number of excited ions. This unique feature of SR permits an increase in the rate of the cooling process in comparison with the traditional laser cooling of the rare earth doped solids with anti-Stokes spontaneous incoherent radiation (fluorescence). This scheme overcomes the limitation of using only low phonon energy glasses for laser cooling.

  2. Laser damage resistant anti-reflection microstructures for mid-infrared metal-ion doped ZnSe gain media

    Science.gov (United States)

    Hobbs, Douglas S.; MacLeod, Bruce D.; Sabatino, Ernest; Mirov, Sergey B.; Martyshkin, Dmitri V.

    2012-11-01

    Power scaling of mid-infrared laser systems based on chromium and iron doped zinc selenide (ZnSe) and zinc sulfide (ZnS) crystals is being advanced through the integration of surface relief anti-reflection microstructures (ARMs) etched directly in the facets of the laser gain media. In this study, a new ARMs texture fabrication process is demonstrated for polycrystalline ZnSe and ZnS material that results in a significant increase in pulsed laser damage resistance combined with an average reflection loss of less than 0.5% over the wavelength range of 1.9-3.0μm. The process was utilized to fabricate ARMs in chromium-doped zinc selenide (Cr2+:ZnSe) materials supplied by IPG Photonics and standardized pulsed laser induced damage threshold (LiDT) measurements at a wavelength of 2.09μm were made using the commercial testing services of Spica Technologies. It was found that the pulsed LiDT of ARMs etched in ZnSe and Cr2+:ZnSe can match or even exceed the level of a well-polished surface, a survivability that is many times higher than an equivalent performance broad-band thin-film AR coating. The results also indicate that the ARMs plasma etch process may find use as a post-polish damage mitigation technique similar to the chemical immersion used to double the damage resistance of fused silica optics. ARMs etched in Cr2+:ZnSe were also evaluated by IPG Photonics for survivability under continuous wave (CW) laser operation at a pump laser wavelength of 1.94μm. Catastrophic damage occurred between power levels of 400-500 kilowatt per square centimeter for both as polished and ARMs textured samples indicating no reduction in CW damage resistance attributable to surface effects.

  3. Passively Q-switched ytterbium-doped ScBO3 laser with black phosphorus saturable absorber

    Science.gov (United States)

    Lu, Dazhi; Pan, Zhongben; Zhang, Rui; Xu, Tianxiang; Yang, Ruilong; Yang, Bingchao; Liu, Zhongyuan; Yu, Haohai; Zhang, Huaijin; Wang, Jiyang

    2016-08-01

    We demonstrate a passively Q-switched Yb3+-doped ScBO3 bulk laser using a black phosphorous (BP) saturable absorber, a two-dimensional semiconductor. The response spectra of BP show that it is suitable as a universal switcher in the spectral range from the visible to midinfrared band. Considering the saturable absorption properties of BP and emission properties of Yb3+-doped crystals, the passively Q-switched bulk laser pulses were realized with the Yb3+:ScBO3 crystal as a gain material and a fabricated BP sample as a Q-switcher. Because of the large energy storage capacity of Yb3+:ScBO3, the maximum output energy is obtained to be 1.4 μJ, which is comparable with the previous reported maximum energy of graphene Q-switched lasers. The obtained results identify the potential capability of BP as a pulse modulator in bulk lasers, and BP plays an increasingly important role in a wide range of its applications, including photonics and optoelectronics.

  4. Laser-Doping through Anodic Aluminium Oxide Layers for Silicon Solar Cells

    OpenAIRE

    2015-01-01

    This paper demonstrates that silicon can be locally doped with aluminium to form localised p+ surface regions by laser-doping through anodic aluminium oxide (AAO) layers formed on the silicon surface. The resulting p+ regions can extend more than 10 μm into the silicon and the electrically active p-type dopant concentration exceeds 1020 cm−3 for the first 6-7 μm of the formed p+ region. Anodic aluminium oxide layers can be doped with other impurities, such as boron and phosphorus, by anodisin...

  5. Laser-excited photoemission spectroscopy study of superconducting boron-doped diamond

    Directory of Open Access Journals (Sweden)

    K. Ishizaka, R. Eguchi, S. Tsuda, T. Kiss, T. Shimojima, T. Yokoya, S. Shin, T. Togashi, S. Watanabe, C.-T. Chen, C.Q. Zhang, Y. Takano, M. Nagao, I. Sakaguchi, T. Takenouchi and H. Kawarada

    2006-01-01

    Full Text Available We have investigated the low-energy electronic state of boron-doped diamond thin film by the laser-excited photoemission spectroscopy. A clear Fermi-edge is observed for samples doped above the semiconductor–metal boundary, together with the characteristic structures at 150×n meV possibly due to the strong electron–lattice coupling effect. In addition, for the superconducting sample, we observed a shift of the leading edge below Tc indicative of a superconducting gap opening. We discuss the electron–lattice coupling and the superconductivity in doped diamond.

  6. Erbium-doped integrated waveguide amplifiers and lasers

    NARCIS (Netherlands)

    Bradley, J.; Pollnau, Markus

    Erbium-doped fiber devices have been extraordinarily successful due to their broad optical gain around 1.5–1.6 μm. Er-doped fiber amplifiers enable efficient, stable amplification of high-speed, wavelength-division-multiplexed signals, thus continue to dominate as part of the backbone of longhaul

  7. Ba-DOPED ZnO MATERIALS: A DFT SIMULATION TO INVESTIGATE THE DOPING EFFECT ON FERROELECTRICITY

    Directory of Open Access Journals (Sweden)

    Luis H. da S. Lacerda

    2016-04-01

    Full Text Available ZnO is a semiconductor material largely employed in the development of several electronic and optical devices due to its unique electronic, optical, piezo-, ferroelectric and structural properties. This study evaluates the properties of Ba-doped wurtzite-ZnO using quantum mechanical simulations based on the Density Functional Theory (DFT allied to hybrid functional B3LYP. The Ba-doping caused increase in lattice parameters and slight distortions at the unit cell angle in a wurtzite structure. In addition, the doping process presented decrease in the band-gap (Eg at low percentages suggesting band-gap engineering. For low doping amounts, the wavelength characteristic was observed in the visible range; whereas, for middle and high doping amounts, the wavelength belongs to the Ultraviolet range. The Ba atoms also influence the ferroelectric property, which is improved linearly with the doping amount, except for doping at 100% or wurtzite-BaO. The ferroelectric results indicate the ZnO:Ba is an strong option to replace perovskite materials in ferroelectric and flash-type memory devices.

  8. Impurities good and bad: Doped cluster nanoplasmas in intense laser fields and characterization of impurity level

    Indian Academy of Sciences (India)

    J Jha; M Krishnamurthy

    2010-12-01

    Doping of cluster-based targets can bring out considerable modifications in the evolution of the nanoplasma formed from clusters in intense laser fields. The consequence could be either an increase or, a decrease (depending upon the properties and proportion of the dopant) in the emission of the resulting charge particles or photons from nanoplasma. As we can control the percentage of CS2 in the doped Ar-CS2 cluster, we can have argon-doped CS2 cluster (when argon constitutes about 10–40%) and CS2-doped argon cluster (when fraction of CS2 is 10–40%). In the experimental studies of electron spectra and X-ray emission from pristine Ar ( ≤ 25, 000) and doped Ar-CS2 clusters at laser intensities of about 1015 W cm-2, it is observed that there is more than an order of magnitude enhancement in those emissions in doped Ar-CS2 clusters than in the former case. Conversely, a significant reduction in those emissions was found in the latter case. Such observations signify the importance of characterization of these targets. In this direction, we demonstrate a simple method for the characterization of doping level based on the Rayleigh scattering measurements.

  9. Yb3+-Doped Double-Clad Fibre Laser Based on Fibre Bragg Grating

    Institute of Scientific and Technical Information of China (English)

    范万德; 付圣贵; 张强; 宁鼎; 李丽君; 王志; 袁树忠; 董孝义

    2003-01-01

    A novel Yb3+-doped double-clad fibre laser based on a double-clad fibre Bragg grating is presented. The fibre Bragg grating, as the output mirror, has been formed in Yb3+-doped double-clad fibre with the phase-mask method. When the input pump power is 2.8 W, the maximum laser output power is 570mW, with < 0.2 nm in line-width at the wavelength of 1.058μm, over 40dB signal-to-noise ratio and 24% slope efficiency.

  10. Widely tunable erbium-doped fiber laser based on multimode interference effect.

    Science.gov (United States)

    Castillo-Guzman, A; Antonio-Lopez, J E; Selvas-Aguilar, R; May-Arrioja, D A; Estudillo-Ayala, J; LiKamWa, P

    2010-01-18

    A widely tunable erbium-doped all-fiber laser has been demonstrated. The tunable mechanism is based on a novel tunable filter using multimode interference effects (MMI). The tunable MMI filter was applied to fabricate a tunable erbium-doped fiber laser via a standard ring cavity. A tuning range of 60 nm was obtained, ranging from 1549 nm to 1609 nm, with a signal to noise ratio of 40 dB. The tunable MMI filter mechanism is very simple and inexpensive, but also quite efficient as a wavelength tunable filter.

  11. Multi-wavelength erbium-doped fiber laser based on random distributed feedback

    Science.gov (United States)

    Liu, Yuanyang; Dong, Xinyong; Jiang, Meng; Yu, Xia; Shum, Ping

    2016-09-01

    We experimentally demonstrated a multi-wavelength erbium-doped fiber laser based on random distributed feedback via a 20-km-long single-mode fiber together with a Sagnac loop mirror. The number of channels can be modulated from 2 to 8 at room temperature when the pump power is changed from 30 to 180 mW, indicating that wavelength competition caused by homogenous gain broadening of erbium-doped fiber is significantly suppressed. Other advantages of the laser include low cost, low-threshold pump power and simple fabrication.

  12. Highly stable and efficient erbium-doped 2.8 microm all fiber laser.

    Science.gov (United States)

    Bernier, Martin; Faucher, Dominic; Caron, Nicolas; Vallée, Réal

    2009-09-14

    We demonstrate the efficient and stable CW laser operation at 2.824 microm of a diode-pumped erbium-doped fluoride fiber laser employing an intracore fiber Bragg grating high reflector. An output power of 5 W and an optical-to-optical conversion efficiency of 32% are reported. The temporal and spectral stability of the laser represent a significant improvement over previous work. This report paves the way to the commercialization of compact and stable fiber lasers for spectroscopic and medical applications.

  13. Multi-wavelength hybrid gain fiber ring laser based on Raman and erbium-doped fiber

    Institute of Scientific and Technical Information of China (English)

    Shan Qin; Yongbo Tang; Daru Chen

    2006-01-01

    A stable and uniform multi-wavelength fiber laser based on the hybrid gain of a dispersion compensating fiber as the Raman gain medium and an erbium-doped fiber (EDF) is introduced. The gain competition effects in the fiber Raman amplification (FRA) and EDF amplification are analyzed and compared experimentaUy. The FRA gain mechanism can suppress the gain competition effectively and make the present multi-wavelength laser stable at room temperature. The hybrid gain medium can also increase the lasing bandwidth compared with a pure EDF laser, and improve the power conversion efficiency compared with a pure fiber Raman laser.

  14. Effect of High Z material on the performance of an air-breathing laser ablation thruster

    Science.gov (United States)

    Shimamura, Kohei; Kiyono, Inoru; Yokota, Ippei; Ozaki, Naoto; Yokota, Shigeru

    2016-09-01

    A Laser propulsion, such as a Lightcraft, is a candidate for the low cost transportation system between the ground to space instead of the chemical rocket. Using the shock wave induced by focusing laser beam on the ablator in air, the huge fuel is unnecessary to generate the thrust. In this study, the high-Z material was doped into the polystyrene to emphasize the ionization effect in air. We evaluate the intensity of the bremsstrahlung radiation, the plasma parameter, and the thrust performance.

  15. High-power Yb-doped continuous-wave and pulsed fibre lasers

    Indian Academy of Sciences (India)

    B N Upadhyaya

    2014-01-01

    High-power laser generation using Yb-doped double-clad fibres with conversion efficiencies in excess of 80% have attracted much attention during the last decade due to their inherent advantages in terms of very high efficiency, no misalignment due to in-built intracore fibre Bragg gratings, low thermal problems due to large surface to volume ratio, diffraction-limited beam quality, compactness, reliability and fibre-optic beam delivery. Yb-doped fibres can also provide a wide emission band from ∼1010 nm to ∼1170 nm, which makes it a versatile laser medium to realize continuous-wave (CW), Q-switched short pulse, and mode-locked ultrashort pulse generation for various applications. In this article, a review of Yb-doped CW and pulsed fibre lasers along with our study on self-pulsing dynamics in CW fibre lasers to find its role in high-power fibre laser development and the physical mechanisms involved in its generation has been described. A study on the generation of high-power CWfibre laser of 165Woutput power and generation of high peak power nanosecond pulses from acousto-optic Q-switched fibre laser has also been presented.

  16. Scandium-doped zinc cadmium oxide as a new stable n-type oxide thermoelectric material

    DEFF Research Database (Denmark)

    Han, Li; Christensen, Dennis Valbjørn; Bhowmik, Arghya

    2016-01-01

    Scandium-doped zinc cadmium oxide (Sc-doped ZnCdO) is proposed as a new n-type oxide thermoelectric material. The material is sintered in air to maintain the oxygen stoichiometry and avoid instability issues. The successful alloying of CdO with ZnO at a molar ratio of 1 : 9 significantly reduced...

  17. Dynamics of an erbium-doped fiber laser subjected to harmonic modulation of a diode pump laser

    Science.gov (United States)

    Pisarchik, Alexander N.; Kir'yanov, Alexander V.; Barmenkov, Yuri O.; Reategui, R. J.

    2004-10-01

    An erbium-doped fiber laser is shown to operate as a bistable or multistable nonlinear system under harmonic modulation of the diode pump laser. Phase- and frequency-dependent states are demonstrated both experimentally and in numerical simulations through codimensional-one and codimensional-two bifurcation diagrams in the parameter space of the modulation frequency and amplitude. In particular, generalized bistability results in doubling of saddle-node bifurcation lines where different coexisting attractors born. The laser model describes well all experimental features.

  18. Novel intra-cavity self-organization coherent erbium-doped fiber laser

    Institute of Scientific and Technical Information of China (English)

    JIA Xiu-jie; LIU Feng-nian; FU Sheng-gui; ZHANG Jian; LIU Yan-ge; GUO Zhan-cheng; YUAN Shu-zhong; KAI Gui-yun; DONG Xiao-yi

    2007-01-01

    A novel all-fiber self-organization coherent Erbium-doped fiber laser is proposed and demonstrated. The laser system is composed of two independent lasers. When each of the two branch lasers operates independently, the output power is 10.41 mW and 8.69 mW respectively. By adjusting a polarization controller (PC), the two lasers achieve coherent coupling,and the output power is 24.4 mW, which is more than two times that the single laser yields. Furthermore, we bring forward and discuss the factor estimating the effect of coherent combination-coherent coupling factor. The value of growth factor to evaluate the effect of coherent combining is 1.27. The coherent fiber laser has the advantages of simple structure, high efficiency and single frequency, which conduce to coherent coupling easily.

  19. Dynamics of the guest-host orientational interaction in dye-doped liquid-crystalline materials.

    Science.gov (United States)

    Truong, Thai V; Xu, Lei; Shen, Y R

    2005-11-01

    We present a comprehensive study on the dynamics of laser-induced molecular reorientation in a dye-doped liquid crystalline (LC) medium that exhibits significant enhancement of the optical Kerr nonlinearity due to guest-host interaction. Using various techniques, we separately characterized the dynamical responses of the relevant molecular species present in the medium following photoexcitation and, thus, were able to follow the transient process in which photoexcitation of the dye molecules exert through guest-host interaction a net torque on the host LC material, leading to the observed enhanced optical Kerr nonlinearity. Experimental results agree quantitatively with the time-dependent theory based on a mean-field model of the guest-host interaction.

  20. Degradation of optical properties of a film-type single-wall carbon nanotubes saturable absorber (SWNT-SA) with an Er-doped all-fiber laser.

    Science.gov (United States)

    Ryu, Sung Yoon; Kim, Kyung-Soo; Kim, Jungwon; Kim, Soohyun

    2012-06-04

    Single-wall carbon nanotubes (SWNTs) are promising materials for saturable absorbers (SAs) in mode-locked lasers. However it has been widely recognized that the degradation of optical properties of film-type SWNTs used in femtosecond mode-locked lasers limits the achievable long-term stability of such lasers. In this paper, we study the degradation of optical properties of SWNT-SA fabricated as sandwich type using HiPCO SWNTs with an Er-doped all-fiber laser. The thresholds of laser pump power are examined to avoid the damage of the SWNT-SA. Based on the proposed analysis, it is shown that all-fiber laser pulses of 300 fs pulse width, 3.85 mW average output power, 211.7 MW/cm² peak intensity and 69.9 MHz repetition rate can be reliably generated without any significant damage to the SWNT-SA film.

  1. Laser-shocked energetic materials with metal additives: evaluation of chemistry and detonation performance.

    Science.gov (United States)

    Gottfried, Jennifer L; Bukowski, Eric J

    2017-01-20

    A focused, nanosecond-pulsed laser has been used to ablate, atomize, ionize, and excite milligram quantities of metal-doped energetic materials that undergo exothermic reactions in the laser-induced plasma. The subsequent shock wave expansion in the air above the sample has been monitored using high-speed schlieren imaging in a recently developed technique, laser-induced air shock from energetic materials (LASEM). The method enables the estimation of detonation velocities based on the measured laser-induced air-shock velocities and has previously been demonstrated for organic military explosives. Here, the LASEM technique has been extended to explosive formulations with metal additives. A comparison of the measured laser-induced air-shock velocities for TNT, RDX, DNTF, and LLM-172 doped with Al or B to the detonation velocities predicted by the thermochemical code CHEETAH for inert or active metal participation demonstrates that LASEM has potential for predicting the early time (<10  μs) participation of metal additives in detonation events. The LASEM results show that while Al is mostly inert at early times in the detonation event (confirmed from large-scale detonation testing), B is active-and reducing the amount of hydrogen present during the early chemical reactions increases the resulting estimated detonation velocities.

  2. Photoactive Nanomaterials Inspired by Nature: LTL Zeolite Doped with Laser Dyes as Artificial Light Harvesting Systems

    Directory of Open Access Journals (Sweden)

    Leire Gartzia-Rivero

    2017-05-01

    Full Text Available The herein reported work describes the development of hierarchically-organized fluorescent nanomaterials inspired by plant antenna systems. These hybrid materials are based on nanostructured zeolitic materials (LTL zeolite doped with laser dyes, which implies a synergism between organic and inorganic moieties. The non-interconnected channeled structure and pore dimensions (7.1 Å of the inorganic host are ideal to order and align the allocated fluorophores inside, inferring also high thermal and chemical stability. These artificial antennae harvest a broad range of chromatic radiation and convert it into predominant red-edge or alternatively white-light emission, just choosing the right dye combination and concentration ratio to modulate the efficiency of the ongoing energy transfer hops. A further degree of organization can be achieved by functionalizing the channel entrances of LTL zeolite with specific tailor-made (stopcock molecules via a covalent linkage. These molecules plug the channels to avoid the leakage of the guest molecules absorbed inside, as well as connect the inner space of the zeolite with the outside thanks to energy transfer processes, making the coupling of the material with external devices easier.

  3. Practical Method for engineering Erbium-doped fiber lasers from step-like pulse excitations

    Energy Technology Data Exchange (ETDEWEB)

    Causado-Buelvas, J D; Gomez-Cardona, N D; Torres, P, E-mail: jdcausad@unal.edu.co [Escuela de fisica, Universidad Nacional de Colombia-sede Medellin A.A.3840, Medellin (Colombia)

    2011-01-01

    A simple method, known as 'easy points', has been applied to the characterization of Erbium-doped fibers, aiming for the engineering of fiber lasers. Using low- optical-power flattop pulse excitations it has been possible to determine both the attenuation coefficients and the intrinsic saturation powers of doped single-mode fibers at 980 and 1550 nm. Laser systems have been projected for which the optimal fiber length and output power have been determined as a function of the input power. Ring and linear laser cavities have been set up, and the characteristics of the output laser have been obtained and compared with the theoretical predictions based on the 'easy points' parameters.

  4. Erbium-doped all-fiber laser at 2.94 microm.

    Science.gov (United States)

    Faucher, Dominic; Bernier, Martin; Caron, Nicolas; Vallée, Réal

    2009-11-01

    We report what we believe is the first demonstration of laser emission at 2.94 microm in an erbium-doped fluoride fiber laser. The low-loss all-fiber Fabry-Perot laser cavity was formed by two fiber Bragg gratings of 90% and 15% reflectivities in a 6.6 m, 7 mol.% Er-doped double-clad fiber. A maximum cw output power of 5.2 W was measured, which is to our knowledge the highest reported to date for a diode-pumped laser at this wavelength. A coreless endcap was fused at the output fiber end to prevent its deterioration at high output powers. Our results, including the slope efficiency of 26.6% with respect to launched pump power, suggest that erbium could be a better alternative than holmium in the search for a replacement for the flashlamp-pumped Er:YAG at 2.94 microm.

  5. Dynamics expansion of laser produced plasma with different materials in magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Rabia Qindeel; Noriah Bte Bidin; Yaacob Mat daud [Laser Technology Laboratory, Physics Department, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia)], E-mail: plasmaqindeel@yahoo.com

    2008-12-01

    The dynamics expansion of the plasma generated by laser ablation of different materials has been investigated. The dynamics and confinement of laser generated plasma plumes are expanding across variable magnetic fields. A Q-switched neodymium-doped yttrium aluminum garnet laser with 1064 nm, 8 ns pulse width and 0.125 J laser energy was used to generate plasma that was allowed to expand across variable magnetic within 0.1 - 0.8 T. The expansions of laser-produced plasma of different materials are characterized by using constant laser power. CCD video camera was used to visualize and record the activities in the focal region. The plasma plume length, width and area were measured by using Matrox Inpector 2.1 and video Test 0.5 software. Spectrums of plasma beam from different materials are studied via spectrometer. The results show that the plasma generated by aluminum target is the largest than Brass and copper. The optical radiation from laser generated plasma beam spectrums are obtained in the range of UV to visible light.

  6. Rugosity and hardness determination in obsidianus lapis for the design of an Yb3+-doped fiber laser

    Science.gov (United States)

    Alvarez-Chavez, J. A.; Aguilar-Morales, A. I.; Perez-Sanchez, G. G.; Morales-Ramirez, A. J.

    2015-01-01

    Obsidianus lapis is a volcanic rock that has been worked into tools for cutting or weaponry by Teotihuacan people for hundreds of years. Currently, it is used in jewelry or for house decorative items such as elaborated sculptures. From the physico-chemical properties point of view, obsidianus lapis is considered a glass as its composition is 80% silicon dioxide. In México, there are different kinds of obsidianus lapis which are classified according to its colour: rainbow, black, brown, red, silver, golden and snowflake. The traditional grinding process for working with obsidianus lapis includes fixed grinders and sandpaper for the polishing process, where the craftsman grinds the rock manually for obtaining a variety of shapes. Laser processing of natural stones is a relatively new area. We propose the use of an Yb3+-doped fibre laser for cutting and ablating obsidianus lapis into spherical, rectangular and oval shapes. By means of a theoretical analysis of roughness and hardness, which affect the different surfaces and final shapes, and by considering the changes in material temperature during laser interaction, this work will focus on parameter determination such as: laser fluence, incidence angle, laser average power and peak pulse energy, from the proposed Q-switched fibre laser design. Full optical, hardness and rugosity, initial and final characterization will be included in the presentation.

  7. Single-frequency, single-polarization holmium-doped ZBLAN fiber laser

    Science.gov (United States)

    Zhu, X.; Zong, J.; Miller, A.; Wiersma, K.; Norwood, R. A.; Prasad, N. S.; Chavez-Pirson, A.; Peyghambarian, N.

    2013-02-01

    We present the performance of a single frequency, single-polarization holmium (Ho3+)-doped ZBLAN (ZrF4-BaF2-LaF3- AlF3-NaF) fiber laser at 1200 nm. This distributed Bragg reflector (DBR) fiber laser was developed by splicing a 22 mm long highly Ho3+-doped ZBLAN fiber to a pair of silica fiber Bragg gratings (FBG). The successful fusion splicing of silica fiber to ZBLAN fiber, with their very different melting temperatures, was accomplished by using NP Photonics proprietary splicing technique. The 3 mol% Ho3+-doped ZBLAN fiber had a core diameter of 6.5 μm and a cladding diameter of 125 μm. The threshold of this laser was seen to be about 260 mW, and when the pump power was 520 mW, the output power was about 10 mW. The efficiency of the 1200 nm single-frequency fiber laser, i.e. the ratio of the output power to the launched pump power, was about 3.8%. The linewidth of the 1200 nm single-frequency fiber laser was estimated to be about 100 kHz by comparing the measured frequency noise of the 1200 nm single-frequency fiber laser with that of 1 μm NP Photonics single-frequency fiber lasers whose linewidths have been measured to be in the 1- 10 kHz range. The relative intensity noise of this DBR all-fiber laser was measured to be 19 dB. Due to its low phonon energy and long radiative lifetimes, rare-earth-doped ZBLAN allows various transitions that are typically terminated in silica glass, resulting in ultraviolet, visible, and infrared rare-earth doped ZBLAN lasers. Therefore, our results highlight the exciting prospect that the accessible wavelength range of single-frequency DBR fiber lasers can be expanded significantly by using rare-earth-doped ZBLAN fibers.

  8. Nonlinear resonance phenomena of a doped fibre laser under cavity-loss modulation: Experimental demonstrations

    Indian Academy of Sciences (India)

    A Ghosh; B K Goswami; R Vijaya

    2010-11-01

    Our experiments with an erbium-doped fibre ring laser (CW, single transverse mode and multiaxial mode) with an intracavity LiNbO3 electro-optic modulator (EOM) display the characteristic features of a nonlinear oscillator (e.g., harmonic and period-2 sub-harmonic resonances) when the EOM driver voltage is modulated periodically. Harmonic resonance leads to period-1 bistability and hysteresis. Inside the period-2 sub-harmonic resonance region, the laser exhibits Feigenbaum sequence and generalized bistability.

  9. A compact single-polarization erbium-doped fiber laser by exploiting vernier effect

    Institute of Scientific and Technical Information of China (English)

    Xiangqiao Mao; Fengping Yan; Yongjun Fu; Lin Wang; Jian Peng; Lisong Liu; Shuisheng Jian

    2009-01-01

    @@ A compact single-polarization fiber laser with fiber Bragg gratings inscripted in a polarization-maintaining erbium-doped germanosilicate fiber is demonstrated experimentally.The single-wavelength and single-polarization regime of our studied laser is achieved by applying a radial stress upon one of two gratings and stretching the other one axially to adjust the reflection peak match.Two single-wavelength and single-polarization lasing lines are realized respectively with fine power stability.

  10. Self-similar erbium-doped fiber laser with large normal dispersion.

    Science.gov (United States)

    Liu, Hui; Liu, Zhanwei; Lamb, Erin S; Wise, Frank

    2014-02-15

    We report a large normal dispersion erbium-doped fiber laser with self-similar pulse evolution in the gain fiber. The cavity is stabilized by the local nonlinear attractor in the gain fiber through the use of a narrow filter. Experimental results are accounted for by numerical simulations. This laser produces 3.5 nJ pulses, which can be dechirped to 70 fs with an external grating pair.

  11. Observation of central wavelength dynamics in erbium-doped fiber ring laser.

    Science.gov (United States)

    Xu, Huiwen; Lei, Dajun; Wen, Shuangchun; Fu, Xiquan; Zhang, Jinggui; Shao, Yufeng; Zhang, Lifu; Zhang, Hua; Fan, Dianyuan

    2008-05-12

    We report on the observation of central wavelength dynamics in an erbium-doped fiber ring laser by using the nonlinear polarization rotating technique. The evolution of central wavelength with the laser operation state was observed experimentally. Numerical simulations confirmed the experimental observation and further demonstrated that the dynamics of wavelength evolution is due to the combined effects of fiber birefringence, fiber nonlinearity, and cavity filter.

  12. Large energy mode locking of an erbium-doped fiber laser with atomic layer graphene.

    Science.gov (United States)

    Zhang, H; Tang, D Y; Zhao, L M; Bao, Q L; Loh, K P

    2009-09-28

    We report on large energy pulse generation in an erbium-doped fiber laser passively mode-locked with atomic layer graphene. Stable mode locked pulses with single pulse energy up to 7.3 nJ and pulse width of 415 fs have been directly generated from the laser. Our results show that atomic layer graphene could be a promising saturable absorber for large energy mode locking.

  13. Self-similar erbium-doped fiber laser with large normal dispersion

    OpenAIRE

    Liu, Hui; Liu, Zhanwei; Lamb, Erin S.; Wise, Frank

    2014-01-01

    We report a large normal dispersion erbium-doped fiber laser with self-similar pulse evolution in the gain fiber. The cavity is stabilized by the local nonlinear attractor in the gain fiber through the use of a narrow filter. Experimental results are accounted for by numerical simulations. This laser produces 3.5 nJ pulses, which can be dechirped to 70 fs with an external grating pair.

  14. Dissipative soliton resonance in an all-normal-dispersion erbium-doped fiber laser.

    Science.gov (United States)

    Wu, X; Tang, D Y; Zhang, H; Zhao, L M

    2009-03-30

    We report on the generation of 281.2 nJ mode locked pulses directly from an erbium-doped fiber laser mode-locked with the nonlinear polarization rotation technique. We show that apart from the conventional dissipative soliton operation, an all-normal-dispersion fiber laser can also emit square-profile dissipative solitons whose energy could increase to a very large value without pulse breaking.

  15. A 980 nm pseudomorphic single quantum well laser for pumping erbium-doped optical fiber amplifiers

    Science.gov (United States)

    Larsson, A.; Forouhar, S.; Cody, J.; Lang, R. J.; Andrekson, P. A.

    1990-01-01

    The authors have fabricated ridge waveguide pseudomorphic InGaAs/GaAs/AlGaAs GRIN-SCH SQW (graded-index separate-confinement-heterostructure single-quantum-well) lasers, emitting at 980 nm, with a maximum output power of 240 mW from one facet and a 22 percent coupling efficiency into a 1.55-micron single-mode optical fiber. These lasers satisfy the requirements on efficient and compact pump sources for Er3+-doped fiber amplifiers.

  16. Laser Induced Modification of the Optical Properties of Nano-ZnO Doped PVC Films

    OpenAIRE

    Hamad, Tagreed K.; Yusop, Rahimi M.; Wasan A. Al-Taa’y; Bashar Abdullah; Emad Yousif

    2014-01-01

    The effect of continuous CO2 laser radiation on the optical properties of pure polyvinyl chloride and doped of ZnO nanoparticles with two different concentrations (10, 15%) has been investigated. All samples were prepared using casting method at room temperature. Optical properties (absorption, transmission, absorption coefficient, extinction coefficient, refractive index, and optical conductivity) of all films after CO2 laser irradiated have been studied as a function of the wavelength in th...

  17. Ultrafast lasers--reliable tools for advanced materials processing

    National Research Council Canada - National Science Library

    Koji Sugioka; Ya Cheng

    2014-01-01

      The unique characteristics of ultrafast lasers, such as picosecond and femtosecond lasers, have opened up new avenues in materials processing that employ ultrashort pulse widths and extremely high peak intensities...

  18. Laser Additive Manufacturing of Magnetic Materials

    Science.gov (United States)

    Mikler, C. V.; Chaudhary, V.; Borkar, T.; Soni, V.; Jaeger, D.; Chen, X.; Contieri, R.; Ramanujan, R. V.; Banerjee, R.

    2017-03-01

    While laser additive manufacturing is becoming increasingly important in the context of next-generation manufacturing technologies, most current research efforts focus on optimizing process parameters for the processing of mature alloys for structural applications (primarily stainless steels, titanium base, and nickel base alloys) from pre-alloyed powder feedstocks to achieve properties superior to conventionally processed counterparts. However, laser additive manufacturing or processing can also be applied to functional materials. This article focuses on the use of directed energy deposition-based additive manufacturing technologies, such as the laser engineered net shaping (LENS™) process, to deposit magnetic alloys. Three case studies are presented: Fe-30 at.%Ni, permalloys of the type Ni-Fe-V and Ni-Fe-Mo, and Fe-Si-B-Cu-Nb (derived from Finemet) alloys. All these alloys have been processed from a blend of elemental powders used as the feedstock, and their resultant microstructures, phase formation, and magnetic properties are discussed in this paper. Although these alloys were produced from a blend of elemental powders, they exhibited relatively uniform microstructures and comparable magnetic properties to those of their conventionally processed counterparts.

  19. Research on cathode material of Li-ion battery by yttrium doping

    Institute of Scientific and Technical Information of China (English)

    TIAN Yanwen; KANG Xiaoxue; LIU Liying; XU Chaqing; QU Tao

    2008-01-01

    Modification of LiFePO4, LiMn2O4 and Li1+xV3O8 by doping yttrium was investigated. The influences of doping Y on structure, morphology and electrochemical performance of cathode materials were investigated systematically. The results indicated that the mechanisms of Y doping in three cathode materials were different, so the influences on the material performance were different. The crystal structure of the three materials was not changed by Y doping. However, the crystal parameters were influenced. The crystal parameters of LiMn2O4 became smaller, and the interlayer distance of (100) crystal plane of Li1+xV3O8 was lengthened after Y doping. The grain size of Y-doped LiFePO4 became smaller and grain morphology became more regular than that of undoped LiFePO4. It indicated that Y doping had no influence on crystal particle and morphology of LiMn2O4. The morphology of Li1+xV3O8 became irregular and its size became larger with the increase of Y. For LiFePO4 and Li1+xV3O8, both the initial discharge capacities and the cyclic performance were improved by Y doping. For LiMn2O4, the cyclic performance became better and the initial discharge capacities declined with increasing Y doping.

  20. Band gap narrowing models tested on low recombination phosphorus laser doped silicon

    Science.gov (United States)

    Dahlinger, Morris; Carstens, Kai

    2016-10-01

    This manuscript discusses bandgap narrowing models for highly phosphorus doped silicon. We simulate the recombination current pre-factor J0,phos in PC1Dmod 6.2 of measured doping profiles and apply the theoretical band gap narrowing model of Schenk [J. Appl. Phys. 84, 3684 (1998)] and an empirical band gap narrowing model of Yan and Cuevas [J. Appl. Phys. 114, 044508 (2013)]. The recombination current pre-factor of unpassivated and passivated samples measured by the photo conductance measurement and simulated J0,phos agrees well, when the band gap narrowing model of Yan and Cuevas is applied. With the band gap narrowing model of Schenk, the simulation cannot reproduce the measured J0,phos. Furthermore, the recombination current pre-factor of our phosphorus laser doped silicon samples are comparable with furnace diffused samples. There is no indication of recombination active defects, thus no laser induced defects in the diffused volume.

  1. Tunable erbium-doped microbubble laser fabricated by sol-gel coating

    CERN Document Server

    Yang, Yong; Kasumie, Sho; Xu, Linhua; Ward, Jonathan; Yang, Lan; Chormaic, Síle Nic

    2016-01-01

    In this work, we show that the application of a sol-gel coating renders a microbubble whispering gallery resonator into an active device. During the fabrication of the resonator, a thin layer of erbium-doped sol-gel is applied to a tapered microcapillary, then a microbubble with a wall thickness of 1.3 $\\mu$m is formed with the rare earth diffused into its walls. The doped microbubble is pumped at 980 nm and lasing in the emission band of the Er$^{3+}$ ions with a wavelength of 1535 nm is observed. The laser wavelength can be tuned by aerostatic pressure tuning of the whispering gallery modes of the microbubble. Up to 240 pm tuning is observed with 2 bar of applied pressure. It is shown that the doped microbubble could be used as a compact, tunable laser source. The lasing microbubble can also be used to improve sensing capabilities in optofluidic sensing applications.

  2. Parametric studies on the nanosecond laser micromachining of the materials

    Science.gov (United States)

    Tański, M.; Mizeraczyk, J.

    2016-12-01

    In this paper the results of an experimental studies on nanosecond laser micromachining of selected materials are presented. Tested materials were thin plates made of aluminium, silicon, stainless steel (AISI 304) and copper. Micromachining of those materials was carried out using a solid state laser with second harmonic generation λ = 532 nm and a pulse width of τ = 45 ns. The effect of laser drilling using single laser pulse and a burst of laser pulses, as well as laser cutting was studied. The influence of laser fluence on the diameter and morphology of a post ablation holes drilled with a single laser pulse was investigated. The ablation fluence threshold (Fth) of tested materials was experimentally determined. Also the drilling rate (average depth per single laser pulse) of holes drilled with a burst of laser pulses was determined for all tested materials. The studies of laser cutting process revealed that a groove depth increases with increasing average laser power and decreasing cutting speed. It was also found that depth of the laser cut grooves is a linear function of number of repetition of a cut. The quantitative influence of those parameters on the groove depth was investigated.

  3. Pulsed laser deposition of aluminum-doped ZnO films at 355 nm

    DEFF Research Database (Denmark)

    Holmelund, E.; Schou, Jørgen; Thestrup Nielsen, Birgitte;

    2004-01-01

    Conducting, transparent films of aluminium-doped ZnO (AZO) have been produced at the laser wavelength 355 nm. The most critical property, the electric resistivity, is up to a factor of 8 above that for films produced at shorter wavelengths. In contrast, the transmission of visible light through...

  4. Analysis of New Q-switched Erbium Doped Fiber Laser Based on Fiber Grating Loop Mirror

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An all-fiber wavelength selective Q-switching modulator based on fiber grating loop mirror is proposed. A newly configured Q-switched erbium doped fiber laser using this all-fiber modulator is numerically analyzed taking into account the effects of the spontaneous emission.

  5. Switchable random laser from dye-doped polymer dispersed liquid crystal waveguides

    NARCIS (Netherlands)

    Xiao, Shumin; Song, Qinghai; Wang, Feng; Liu, Liying; Liu, Jianhua; Xu, Lei

    2007-01-01

    A dye-doped polymer-dispersed liquid crystal (PDLC) film has been fabricated for random lasing action. In this PDLC film, the sizes of most liquid crystal (LC) droplets ranged from 200 to 500 nm. When the sample is optically pumped, ultrahigh Q (>10 000) lasing modes and a collimated laser beam can

  6. Power distribution in Yb3+-doped double-cladding fiber laser

    Institute of Scientific and Technical Information of China (English)

    Qiang Zhang(张强); Jianquan Yao(姚建铨); Peng Wang(王鹏); Jianing Zhou(周佳凝); Yuanqin Xia(夏元钦); Baigang Zhang(张百钢)

    2004-01-01

    The distribution of pump light and signal light in Yb3+-doped double-cladding fiber laser is analyzed based on a rate equation model.Numerical simulation results are obtained.The numerical solution of the rate equation is shown to be in excellent agreement with the experimental data.

  7. Energy recycling versus lifetime quenching in erbium-doped 3-µm fiber lasers

    NARCIS (Netherlands)

    Pollnau, Markus; Jackson, Stuart D.

    Based on recently published spectroscopic measurements of the relevant energy-transfer parameters, we performed a detailed analysis of the population mechanisms and the characteristics of the output from Er3+-singly-doped and Er3+, Pr3+-codoped ZBLAN fiber lasers operating at 3 um, for various Er3+

  8. Coherence and anticoherence resonance in high-concentration erbium-doped fiber laser

    OpenAIRE

    Sergeyev, Sergey; O'Mahoney, Kieran; Popov, Sergei; Friberg, Ari T.

    2010-01-01

    We report an experimental study of low-frequency (~10 kHz) self-pulsing of the output intensity in a high- concentration erbium-doped fiber laser. We suggest that the fast intensity fluctuations caused by multimode and polarization instabilities play the role of an external noise source, leading to low-frequency auto-oscillations through a coherence resonance scenario.

  9. Saturation of the 2.71 µm laser output in erbium doped ZBLAN fibers

    NARCIS (Netherlands)

    Bedö, S.; Pollnau, Markus; Lüthy, W.; Weber, H.P.

    1995-01-01

    The saturation of the 2.71 μm laser output power has been investigated in an erbium doped ZBLAN single-mode fiber with an Er3+ concentration of 5000 ppm mol. The bleaching of the ground state, the absorption coefficient at the pump wavelength and the fluorescence intensities over a wide wavelength

  10. Locking of self-oscillation frequency by pump modulation in an erbium-doped fiber laser

    Science.gov (United States)

    Pisarchik, A. N.; Barmenkov, Yu. O.

    2005-10-01

    Frequency locking of self-oscillations in a diode-pumped erbium-doped fiber laser by external modulation of the diode current is studied experimentally. The coexistence of locking and unlocking regimes is detected. The condition for onset of the bistability and dependences of the frequency detuning on the modulation frequency and amplitude are established. Transitions to torus-chaos are also demonstrated.

  11. Multiphoton upconversion process in Tm 3+ doped ZBLAN glass by CW laser irradiation

    Science.gov (United States)

    Li, Jianfu; Wang, Xiaoli; Jiang, Zhankui

    2009-11-01

    Blue, even ultraviolet emissions and very strong red emissions have been observed in ZBLAN glass doped with Tm 3+ under 800 nm CW laser excitation. The red emissions were demonstrated to be of sequential two-photon process, while the ultraviolet emissions be of three-photon process, according to the intensity dependence.

  12. High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser

    Science.gov (United States)

    Jin, Xiaoxi; Du, Xueyuan; Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Wang, Xiaolin; Liu, Zejin

    2016-07-01

    We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153 nm with the output power exceeding 18 W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173 nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173 nm random distributed feedback fiber laser as pump laser is a feasible and promising scheme to achieve high-power emission of long-wavelength Tm-doped fiber laser. The output power of this Tm-doped fiber laser could be further improved by optimizing the length of active fiber, reflectivity of FBGs, increasing optical efficiency of pump laser and using better temperature management. We also compared the operation of 2153 nm Tm-doped fiber lasers pumped with 793 nm laser diodes, and the maximum output powers were limited to ~2 W by strong amplified spontaneous emission and parasitic oscillation in the range of 1900-2000 nm.

  13. Clad-pumped Er-nanoparticle-doped fiber laser (Conference Presentation)

    Science.gov (United States)

    Baker, Colin C.; Friebele, E. Joseph; Rhonehouse, Daniel L.; Marcheschi, Barbara A.; Peele, John R.; Kim, Woohong; Sanghera, Jasbinder S.; Zhang, Jun; Chen, Youming; Pattnaik, Radha K.; Dubinskii, Mark

    2017-03-01

    Erbium-doped fiber lasers are attractive for directed energy weapons applications because they operate in a wavelength region that is both eye-safer and a window of high atmospheric transmission. For these applications a clad-pumped design is desirable, but the Er absorption must be high because of the areal dilution of the doped core vs. the pump cladding. High Er concentrations typically lead to Er ion clustering, resulting in quenching and upconversion. Nanoparticle (NP) doping of the core overcomes these problems by physically surrounding the Er ions with a cage of Al and O in the NP, which keeps them separated to minimize excited state energy transfer. A significant issue is obtaining high Er concentrations without the NP agglomeration that degrades the optical properties of the fiber core. We have developed the process for synthesizing stable Er-NP suspension which have been used to fabricate EDFs with Er concentrations >90 dB/m at 1532 nm. Matched clad fibers have been evaluated in a core-pumped MOPA with pump and signal wavelengths of 1475 and 1560 nm, respectively, and efficiencies of 72% with respect to absorbed pump have been obtained. We have fabricated both NP- and solution-doped double clad fibers, which have been measured in a clad-pumped laser testbed using a 1532 nm pump. The 1595 nm laser efficiency of the NP-doped fiber was 47.7%, which is high enough for what is believed to be the first laser experiment with the cladding pumped, NP-doped fiber. Further improvements are likely with a shaped cladding and new low-index polymer coatings with lower absorption in the 1500 - 1600 nm range.

  14. Laser-shocked energetic materials with metal additives: evaluation of detonation performance

    Science.gov (United States)

    Gottfried, Jennifer; Bukowski, Eric

    A focused, nanosecond-pulsed laser with sufficient energy to exceed the breakdown threshold of a material generates a laser-induced plasma with high peak temperatures, pressures, and shock velocities. Depending on the laser parameters and material properties, nanograms to micrograms of material is ablated, atomized, ionized and excited in the laser-induced plasma. The subsequent shock wave expansion into the air above the sample has been monitored using high-speed schlieren imaging in a recently developed technique, laser-induced air shock from energetic materials (LASEM). The estimated detonation velocities using LASEM agree well with published experimental values. A comparison of the measured shock velocities for various energetic materials including RDX, DNTF, and LLM-172 doped with Al or B to the detonation velocities predicted by CHEETAH for inert or active metal participation demonstrates that LASEM has potential for predicting the early time participation of metal additives in detonation events. The LASEM results show that reducing the amount of hydrogen present in B formulations increases the resulting detonation velocities

  15. FY 1980 Report on Dye Laser Materials

    Science.gov (United States)

    1981-02-01

    by block number) Dye Lasers Laser Dyes Tunable Lasers Photodegradation Rhodamine Dyes 20. ABSTRACT (Continue n resld* it necesiry and Identify by block...limited usefulness as a portable military device because of the photodegradation of the dye solution. Although there have been state-of-the-art reviews...on laser dyes , 1𔃼 the photodegradation of laser dyes ,3 and dye lasers, 4- 6 only authors from, or funded by, military organizations have given strict

  16. Mechanical characterization of hydroxyapatite, thermoelectric materials and doped ceria

    Science.gov (United States)

    Fan, Xiaofeng

    For a variety of applications of brittle ceramic materials, porosity plays a critical role structurally and/or functionally, such as in engineered bone scaffolds, thermoelectric materials and in solid oxide fuel cells. The presence of porosity will affect the mechanical properties, which are essential to the design and application of porous brittle materials. In this study, the mechanical property versus microstructure relations for bioceramics, thermoelectric (TE) materials and solid oxide fuel cells were investigated. For the bioceramic material hydroxyapatite (HA), the Young's modulus was measured using resonant ultrasound spectroscopy (RUS) as a function of (i) porosity and (ii) microcracking damage state. The fracture strength was measured as a function of porosity using biaxial flexure testing, and the distribution of the fracture strength was studied by Weibull analysis. For the natural mineral tetrahedrite based solid solution thermoelectric material (Cu10Zn2As4S13 - Cu 12Sb4S13), the elastic moduli, hardness and fracture toughness were studied as a function of (i) composition and (ii) ball milling time. For ZiNiSn, a thermoelectric half-Heusler compound, the elastic modulus---porosity and hardness---porosity relations were examined. For the solid oxide fuel cell material, gadolina doped ceria (GDC), the elastic moduli including Young's modulus, shear modulus, bulk modulus and Poisson's ratio were measured by RUS as a function of porosity. The hardness was evaluated by Vickers indentation technique as a function of porosity. The results of the mechanical property versus microstructure relations obtained in this study are of great importance for the design and fabrication of reliable components with service life and a safety factor. The Weibull modulus, which is a measure of the scatter in fracture strength, is the gauge of the mechanical reliability. The elastic moduli and Poisson's ratio are needed in analytical or numerical models of the thermal and

  17. Fatigue mechanism of yttrium-doped hafnium oxide ferroelectric thin films fabricated by pulsed laser deposition.

    Science.gov (United States)

    Huang, Fei; Chen, Xing; Liang, Xiao; Qin, Jun; Zhang, Yan; Huang, Taixing; Wang, Zhuo; Peng, Bo; Zhou, Peiheng; Lu, Haipeng; Zhang, Li; Deng, Longjiang; Liu, Ming; Liu, Qi; Tian, He; Bi, Lei

    2017-02-01

    Owing to their prominent stability and CMOS compatibility, HfO2-based ferroelectric films have attracted great attention as promising candidates for ferroelectric random-access memory applications. A major reliability issue for HfO2 based ferroelectric devices is fatigue. So far, there have been a few studies on the fatigue mechanism of this material. Here, we report a systematic study of the fatigue mechanism of yttrium-doped hafnium oxide (HYO) ferroelectric thin films deposited by pulsed laser deposition. The influence of pulse width, pulse amplitude and temperature on the fatigue behavior of HYO during field cycling is studied. The temperature dependent conduction mechanism is characterized after different fatigue cycles. Domain wall pinning caused by carrier injection at shallow defect centers is found to be the major fatigue mechanism of this material. The fatigued device can fully recover to the fatigue-free state after being heated at 90 °C for 30 min, confirming the shallow trap characteristic of the domain wall pinning defects.

  18. Exploiting nonlinear properties of pure and Sn-doped Bi2Te2Se for passive Q-switching of all-polarization maintaining ytterbium- and erbium-doped fiber lasers.

    Science.gov (United States)

    Bogusławski, Jakub; Kowalczyk, Maciej; Iwanowski, Przemysław; Hruban, Andrzej; Diduszko, Ryszard; Piotrowski, Kazimierz; Dybko, Krzysztof; Wojciechowski, Tomasz; Aleszkiewicz, Marta; Sotor, Jarosław

    2017-08-07

    Due to their broadband nonlinear optical properties, low-dimensional materials are widely used for pulse generation in fiber and solid-state lasers. Here we demonstrate novel materials, Bi2Te2Se (BTS) and Sn-doped Bi2Te2Se (BSTS), which can be used as a universal saturable absorbers for distinct spectral regimes. The material was mechanically exfoliated from a bulk single-crystal and deposited onto a side-polished fiber. We have performed characterization of the fabricated devices and employed them in polarization-maintaining ytterbium- and erbium-doped fiber lasers. This enabled us to obtain self-starting passively Q-switched regime at 1 µm and 1.56 µm. The oscillators emitted stable, linearly polarized radiation with the highest single pulse energy approaching 692 nJ. Both lasers are characterized by the best performance observed in all-polarization maintaining Q-switched fiber lasers with recently investigated new saturable absorbers, which was enabled by a very high damage threshold of the devices. This demonstrates the great potential of the investigated materials for the ultrafast photonics community.

  19. Laser direct writing of modulation-doped nanowire p/n junctions

    Science.gov (United States)

    Nam, Woongsik; Mitchell, James I.; Xu, Xianfan

    2016-12-01

    We demonstrate a single-step, laser-based technique to fabricate axial modulation-doped silicon nanowires. Our method is based on laser-direct-write chemical vapor deposition and has the capability to fabricate nanowires as small as 60 nm, which is far below the diffraction limit of the laser wavelength of 395 nm, with precise control of nanowire position, length, and orientation. By switching dopant gases during nanowire writing, p-n junction nanowires are produced. The p-n junction nanowires are fabricated into multifinger devices with parallel metal contacts and electrically tested to demonstrate diode characteristics.

  20. Synchronously pumped picosecond all-fibre Raman laser based on phosphorus-doped silica fibre.

    Science.gov (United States)

    Kobtsev, Sergey; Kukarin, Sergey; Kokhanovskiy, Alexey

    2015-07-13

    Reported for the first time is picosecond-range pulse generation in an all-fibre Raman laser based on P₂O₅-doped silica fibre. Employment of phosphor-silicate fibre made possible single-cascade spectral transformation of pumping pulses at 1084 nm into 270-ps long Raman laser pulses at 1270 nm. The highest observed fraction of the Stokes component radiation at 1270 nm in the total output of the Raman laser amounted to 30%. The identified optimal duration of the input pulses at which the amount of Stokes component radiation in a ~16-m long phosphorus-based Raman fibre converter reaches its maximum was 140-180 ps.

  1. Wideband multiwavelength erbium-doped fiber ring laser with frequency shifted feedback

    Science.gov (United States)

    Kim, Seung Kwan; Chu, Moo Jung; Lee, Jong Hyun

    2001-04-01

    Wideband multiwavelength erbium-doped fiber ring lasers with frequency shifted feedback are described. The use of an intra-cavity gain flattening filter (GFF) was proposed in order to increase the lasing spectral bandwidth, leading to a demonstration of 34 lasing wavelengths in 28 nm bandwidth in C-band. The GFF induced spectral output power fluctuation is discussed. Multiwavelength operation was also demonstrated for the first time in L-band, where wideband laser operation was obtained without a GFF. Optical bistability and Kerr effect induced pulsation were determined to be limiting factors to stable operation range in this kind of multiwavelength lasers.

  2. Side-pumped short rectangular Nd-doped phosphate glass fiber lasers

    Institute of Scientific and Technical Information of China (English)

    Yulong Tang; Yong Yang; Jianqiu Xu

    2008-01-01

    Watt-level short fiber lasers side-pumped through fiber-to-waveguide couplers are demonstrated. The fiber lasers are fabricated from Nd-doped phosphate glass with large numerical aperture of 0.2 and rectangular cross section of 1.5 × 0.5 (mm). Single transverse mode output is achieved by the gain-guiding effect. Average power of 1 W is generated from a 4.0-cm-long fiber laser with a slope efficiency of 10%.

  3. Single frequency 1083nm ytterbium doped fiber master oscillator power amplifier laser.

    Science.gov (United States)

    Huang, Shenghong; Qin, Guanshi; Shirakawa, Akira; Musha, Mitsuru; Ueda, Ken-Ichi

    2005-09-05

    Single frequency 1083nm ytterbium fiber master oscillator power amplifier system was demonstrated. The oscillator was a linear fiber cavity with loop mirror filter and polarization controller. The loop mirror with unpumped ytterbium fiber as a narrow bandwidth filter discriminated and selected laser longitudinal modes efficiently. Spatial hole burning effect was restrained by adjusting polarization controller appropriately in the linear cavity. The amplifier was 5 m ytterbium doped fiber pumped by 976nm pigtail coupled laser diode. The linewidth of the single frequency laser was about 2 KHz. Output power up to 177 mW was produced under the launched pump power of 332 mW.

  4. Optimization of erbium-doped actively Q-switched fiber laser implemented in symmetric configuration

    OpenAIRE

    Kolpakov, Stanislav A.; Sergeyev, Sergey; Mou, Chengbo; Neil T. Gordon; Zhou, Kaiming

    2014-01-01

    We report the results of an experimental study aimed at improving the performance of actively Q-switched fiber lasers. Unlike generic design schemes employing photonic crystal fibers, largemodal diameter fibers or double-clad fibers, we demonstrate a high-power, actively Q-switched laser based on standard com- munication erbium doped fibers with peak irradiance beyond the state-of-the-art at 3.1 GW/cm2 . The laser had 2.2 kW peak power, 15.5 ns pulse duration and 36.8 µJ pulse energy. We have...

  5. Smart Q-switching for single-pulse generation in an erbium-doped fiber laser.

    Science.gov (United States)

    Escalante-Zarate, Luis; Barmenkov, Yuri O; Kolpakov, Stanislav A; Cruz, José L; Andrés, Miguel V

    2012-02-13

    In this paper, we report an active Q-switching of an erbium-doped fiber laser with special modulation functions and novel laser geometry. We experimentally demonstrate that using such a smart Q-switch approach, Q-switch ripple-free pulses with Gaussian-like shape and 17.3 ns width can be easily obtained. The idea behind the smart Q-switch is to suppress one of two laser waves contra-propagating along the fiber cavity, which arises after Q-cell opening, and to eliminate the minor sub-pulses.

  6. Ultrafast pulse generation from erbium-doped fiber laser modulated by hybrid organic-inorganic halide perovskites

    Science.gov (United States)

    Jiang, Guobao; Miao, Lili; Yi, Jun; Huang, Bin; Peng, Wei; Zou, Yanhong; Huang, Huihui; Hu, Wei; Zhao, Chujun; Wen, Shuangchun

    2017-04-01

    We report the nonlinear optical responses of organic-inorganic halide perovskite CH3NH3PbI3 and its application in ultrafast pulse generation from an erbium-doped fiber laser in the optical communication band. By adopting the Z-scan technique, the third-order nonlinear optical responses of the organic-inorganic halide perovskites have been characterized. An ultrafast optical pulse with a pulse width of 661 fs centered at a wavelength of 1555 nm has been delivered via the nonlinear optical material introduced into the fiber laser cavity. Our experimental results confirm that the organic-inorganic halide perovskite possesses obvious third-order nonlinear optical responses in the C-band window and manifests its application potential in nonlinear optoelectronic devices.

  7. 73-nm tuning of a double-clad Yb3+-doped fiber laser based on a hybrid array

    NARCIS (Netherlands)

    Alvarez-Chavez, J.A.; Martinez-Rios, A.; Torres-Gomez, I.; Gonzalez-Garcia, A.; Offerhaus, H.L.

    2008-01-01

    We report on a wide wavelength tuning in a double-clad ytterbium-doped fiber laser. The laser cavity consists of an array of broadband high-reflection fiber Bragg gratings and a bulk grating as the output coupler and wavelength selection element. The proposed fiber laser configuration combines a low

  8. Measurement of thermal lensing in end-pumped Yb-doped yttrium vanadate crystal and sesquioxide laser ceramics

    Science.gov (United States)

    Pestryakov, E. V.; Petrov, V. V.; Trunov, V. I.; Kirpichnikov, A. V.; Merzliakov, M. A.; Laptev, A. V.; Polyakov, K. V.

    2011-02-01

    The results of theoretical and experimental study of thermal lensing in diode-pumped Yb:YVO4 laser crystal, Yb:Y2O3 and Yb:Sc2O3 laser ceramics are presented. Shown, that influence of thermo-lensing effect is necessary to consider for creation of effective high-intensity femtosecond Yb-doped laser systems.

  9. An efficient low-noise single-frequency 1033 nm Yb3+-doped MOPA phosphate fiber laser system

    Science.gov (United States)

    Deng, Huaqiu; Chen, Dan; Zhao, Qilai; Yang, Changsheng; Zhang, Yuanfei; Zhang, Yuning; Feng, Zhouming; Yang, Zhongmin; Xu, Shanhui

    2017-06-01

    An efficient low-noise, single-frequency 1033 nm master oscillator power amplifier (MOPA) Yb3+-doped phosphate fiber (YPF) laser system is demonstrated. A maximal output power of 612 mW with a laser linewidth of 65 dB and relative intensity noise (RIN) of laser system has applications in the fields of optical frequency standards and beam combining.

  10. EFFECT OF UV LASER ON SPECTRAL PROPERTIES OF BORATE GLASSES DOPED WITH COPPER CHLORIDE NANOCRYSTALS

    Directory of Open Access Journals (Sweden)

    A. N. Babkina

    2017-01-01

    Full Text Available We present the results of the pulsed ultraviolet laser effect on the spectral properties of the potassium-aluminium-borate glasses doped with the copper chloride nanocrystals with the average size of 3.1-6.3 nm. We have studied the changes of the exciton absorption spectra of the CuCl nanocrystals induced by different duration of the laser exposure. The results show the possibility of the laser-induced crystallization and growth of the nanocrystals. For the first time the effect of the irreversible photochromism has been obtained in the potassium-aluminium-borate glasses doped with the copper chloride nanocrystals. The effect is associated with the formation of the temperature stable Cu0n colloidal color centers.

  11. Optical Features of Spherical Gold Nanoparticle-Doped Solid-State Dye Laser Medium

    Science.gov (United States)

    Hoa, D. Q.; Lien, N. T. H.; Duong, V. T. T.; Duong, V.; An, N. T. M.

    2016-05-01

    The development of a new laser medium based on gold nanoparticle/dye-doped polymethylmethacrylate (PMMA) has been investigated. In particular, gold nanoparticles with small (16 nm diameter) spherical shape strongly influenced the absorption and fluorescence emission spectra of [2-[2-[4-(dimethylamino)phenyl]ethenyl]-6-methyl-4 H-pyran-4-ylidene]-propanedinitrile (DCM) laser dye. Fluorescence quenching and enhancement of DCM emission were observed for various concentrations of gold nanoparticles (GNPs). Fluorescence intensity enhancement was recorded for the sample containing 1.5 × 1010 par/mL GNPs and doped with 3 × 10-5 mol/L DCM. Thermal photodegradation was significantly decreased by using low pump energy for laser emission.

  12. High power operation of cladding pumped holmium-doped silica fibre lasers.

    Science.gov (United States)

    Hemming, Alexander; Bennetts, Shayne; Simakov, Nikita; Davidson, Alan; Haub, John; Carter, Adrian

    2013-02-25

    We report the highest power operation of a resonantly cladding-pumped, holmium-doped silica fibre laser. The cladding pumped all-glass fibre utilises a fluorine doped glass layer to provide low loss cladding guidance of the 1.95 µm pump radiation. The operation of both single mode and large-mode area fibre lasers was demonstrated, with up to 140 W of output power achieved. A slope efficiency of 59% versus launched pump power was demonstrated. The free running emission was measured to be 2.12-2.15 µm demonstrating the potential of this architecture to address the long wavelength operation of silica based fibre lasers with high efficiency.

  13. Hybrid mode-locked erbium-doped all-fiber soliton laser with a distributed polarizer.

    Science.gov (United States)

    Chernykh, D S; Krylov, A A; Levchenko, A E; Grebenyukov, V V; Arutunyan, N R; Pozharov, A S; Obraztsova, E D; Dianov, E M

    2014-10-10

    A soliton-type erbium-doped all-fiber ring laser hybrid mode-locked with a co-action of arc-discharge single-walled carbon nanotubes (SWCNTs) and nonlinear polarization evolution (NPE) is demonstrated. For the first time, to the best of our knowledge, boron nitride-doped SWCNTs were used as a saturable absorber for passive mode-locking initiation. Moreover, the NPE was introduced through the implementation of the short-segment polarizing fiber. Owing to the NPE action in the laser cavity, significant pulse length shortening as well as pulse stability improvement were observed as compared with a SWCNTs-only mode-locked laser. The shortest achieved pulse width of near transform-limited solitons was 222 fs at the output average power of 9.1 mW and 45.5 MHz repetition frequency, corresponding to the 0.17 nJ pulse energy.

  14. Monolithic Rare Earth Doped PTR Glass Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of airborne and spaceborne laser systems dictates a number of extremely challenging requirements for such fine optical devices. These requirements...

  15. Materials for diode pumped solid state lasers

    Science.gov (United States)

    Chase, L. L.; Davis, L. E.; Krupke, W. F.; Payne, S. A.

    1991-07-01

    The advantages of semiconductor diode lasers and laser arrays as pump sources for solid state lasers are reviewed. The properties that are desirable in solid state laser media for various diode pumping applications are discussed, and the characteristics of several promising media are summarized.

  16. Highly efficient cascaded P-doped Raman fiber laser pumped by Nd:YVO4 solid-state laser

    Institute of Scientific and Technical Information of China (English)

    Chaohong Huang; Zhiping Cai; Zhengqian Luo; Wencai Huang; Huiying Xu; Chenchun Ye

    2008-01-01

    A highly efficient cascaded P-doped Raman fiber laser (RFL) pumped by a 1064-nm continuous wave (CW) Nd:YVO4 solid-state laser is reported. 1.15-W CW output power at 1484 nm is obtained while the input pump power is 4 W, corresponding to the power conversion efficiency of 28.8%. The threshold pump power for the second-order Stokes radiation is 1.13 W. The slope efficiency is as high as 42.6%. The experimental results are in good agreement with theoretical ones. Furthermore, the power instability of the P-doped RFL at 1484 nm in an hour is observed to be less than 5%.

  17. Optical properties of ion beam modified waveguide materials doped with erbium and silver

    NARCIS (Netherlands)

    Strohhöfer, C. (Christof)

    2002-01-01

    In the first part of this thesis we investigate codoping of erbium-doped waveguide materials with different ions in order to increase the efficiency of erbium-doped optical amplifiers. Codoping with ytterbium can overcome the limitations due to the small absorption cross section of Er3+ in Al2O3 at

  18. Effect of cryogenic temperature on spectroscopic and laser properties of Er, Yb-doped potassium-lanthanum phosphate glass

    Science.gov (United States)

    Švejkar, Richard; Šulc, Jan; Němec, Michal; Jelínková, Helena; Nitsch, Karel; Cihlář, Antonín.; Král, Robert; Nejezchleb, Karel; Nikl, Martin

    2017-05-01

    Glass matrix doped with rare-earth ions is a promising laser active medium for high power laser systems. Due to amorphous structure of glasses the absorption and emission spectra lines are broader in comparison with crystalline materials thus pumping radiation can be absorbed efficiently, moreover much broader gain bandwidth is suitable for generation of ultra-short pulses. Another advantage of the glass matrix is the possibility to fabricate large volume ingots and simultaneously preservation of sufficient optical quality. The lower thermal conductivity of glasses can be compensated by geometry of the active medium for instance shaped into fibres or discs. We present temperature dependence of spectroscopic and laser properties of newly developed Er, Yb - doped potassium-lanthanum phosphate glass, which is appropriate for generation of radiation at 1.53 μm. The sample of Er,Yb:KLaP glassy mixture was cut into disc shape with dimensions of 2.5 mm (thickness) and 5 mm (diameter) and its faces were polished plan-parallelly without being anti-reflection coated. The temperature dependence of the transmission and emission spectra Er,Yb:KLaP together with the fluorescence decay time were measured the temperature range from 80 to 400 K. The fluorescence lifetime of manifold 4I13/2 (upper laser level) prolonged and the intensity of up-conversion radiation decreased with decreasing temperature. The longitudinal excitation of Er,Yb:KLaP was carried out by a fibre-coupled laser diode (pulse duration 2 ms, repetition rate 10 Hz, pump wavelength 969 nm). Laser resonator was hemispherical, with flat pumping mirror (HR @ 1.5 μm) and spherical output coupler (R = 98 % @ 1.5 - 1.6 μm). The Er,Yb:KLaP glass laser properties were investigated in the temperature range 80 - 300 K. The highest slope efficiency with respect to absorbed pumped power was 6.1 % at 80 K. The maximum output of peak amplitude power was 0.71 W at 80 K, i.e. 1.2 times higher than at 300 K. Tunability of laser

  19. Laser additive manufacturing of high-performance materials

    CERN Document Server

    Gu, Dongdong

    2015-01-01

    This book entitled “Laser Additive Manufacturing of High-Performance Materials” covers the specific aspects of laser additive manufacturing of high-performance new materials components based on an unconventional materials incremental manufacturing philosophy, in terms of materials design and preparation, process control and optimization, and theories of physical and chemical metallurgy. This book describes the capabilities and characteristics of the development of new metallic materials components by laser additive manufacturing process, including nanostructured materials, in situ composite materials, particle reinforced metal matrix composites, etc. The topics presented in this book, similar as laser additive manufacturing technology itself, show a significant interdisciplinary feature, integrating laser technology, materials science, metallurgical engineering, and mechanical engineering. This is a book for researchers, students, practicing engineers, and manufacturing industry professionals interested i...

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

    DEFF Research Database (Denmark)

    Dyndgaard, Morten Glarborg

    2001-01-01

    fabricated using plasma enhanced chemical vapor deposition (PECVD) and reactive ion etching (RIE). These processes and the control of the film composition is discussed. Ytterbium doped planar waveguides are demonstrated, and it is shown that codoping with aluminium has a positive influence...

  1. Functionally graded materials produced with high power lasers

    NARCIS (Netherlands)

    de Hosson, J.T.M.; Pei, Y.T.; Kumar, A; Chung, YW; Moore, JJ; Doll, GL; Yatsui, K; Misra, DS

    2002-01-01

    With a well-controlled laser melt injection (LMI) process, for the first time the feasibility is demonstrated to produce SiC particles (SiCp) reinforced Ti6Al4V functionally graded materials (FGMs). SiCp are injected just behind the laser beam into the extended part of the laser melt pool that is fo

  2. Interfacial adhesion of laser clad functionally graded materials

    NARCIS (Netherlands)

    Ocelik, V.; Pei, Y.T.; de Hosson, J.T.M.; Popoola, O; Dahotre, NB; Midea, SJ; Kopech, HM

    2003-01-01

    Two functionally graded coatings were prepared by different laser surface engineering techniques. Laser cladding of AlSi40 powder leads to the formation of functionally graded material (FGM) coating on AI-Si cast alloy substrate. Mapping of strain fields near the laser clad track using the digital i

  3. Energy enhancer for mask based laser materials processing

    DEFF Research Database (Denmark)

    Bastue, Jens; Olsen, Flemmming Ove

    1996-01-01

    A device capable of drastically improving the energy efficiency of present mask based laser materials processing systems is presented. Good accordance between experiments and simulations for a TEA-CO2 laser system designed for laser marking has been demonstrated. The energy efficiency may...

  4. Reconfigurable Solid-state Dye-doped Polymer Ring Resonator Lasers

    Science.gov (United States)

    Chandrahalim, Hengky; Fan, Xudong

    2015-01-01

    This paper presents wavelength configurable on-chip solid-state ring lasers fabricated by a single-mask standard lithography. The single- and coupled-ring resonator hosts were fabricated on a fused-silica wafer and filled with 3,3′-Diethyloxacarbocyanine iodide (CY3), Rhodamine 6G (R6G), and 3,3′-Diethylthiadicarbocyanine iodide (CY5)-doped polymer as the reconfigurable gain media. The recorded lasing threshold was ~220 nJ/mm2 per pulse for the single-ring resonator laser with R6G, marking the lowest threshold shown by solid-state dye-doped polymer lasers fabricated with a standard lithography process on a chip. A single-mode lasing from a coupled-ring resonator system with the lasing threshold of ~360 nJ/mm2 per pulse was also demonstrated through the Vernier effect. The renewability of the dye-doped polymer was examined by removing and redepositing the dye-doped polymer on the same resonator hosts for multiple cycles. We recorded consistent emissions from the devices for all trials, suggesting the feasibility of employing this technology for numerous photonic and biochemical sensing applications that entail for sustainable, reconfigurable, and low lasing threshold coherent light sources on a chip. PMID:26674508

  5. Laser Densification and Doping of Sol-Gel Glasses

    Science.gov (United States)

    1992-02-29

    meeting, Keswick, Aug. 1990. 4. A. Charlton, M. A. Meneses -Nava, D. J. Shaw and T. A. King "Gel-silica lasers and optics", Proc. 4th OGAMM meeting, 105...I. T. McKinnie, M. A. Meneses -Nava and T. A. King "A tunable visible solid state laser" J. Mod. Opt. 39, 1992.

  6. Single-frequency Yb-doped fiber laser with distributed feedback based on a random FBG

    Science.gov (United States)

    Abdullina, S. R.; Vlasov, A. A.; Lobach, I. A.; Belai, O. V.; Shapiro, D. A.; Babin, S. A.

    2016-07-01

    Single-frequency operation of a 1.03 μm fiber laser with random distributed feedback (RDFB) is demonstrated. The laser cavity is based on a 4 cm long fiber Bragg grating (FBG) consisting of 10 homogeneous subgratings with random phase and amplitude of refractive index modulation inscribed in a polarization maintaining (PM) Yb-doped fiber. Such RDFB laser generates single longitudinal mode with output power up to 25 mW, which is 3.5 times higher than that for a DFB laser based on regular π-shifted FBG of the same length in the same fiber. The single-frequency linewidth is measured to be  <100 kHz in both cases. The observed difference of the DFB and RDFB lasers is confirmed by numerical simulation showing different longitudinal distribution of intra-cavity radiation in these cases, analogous to those in the experiment.

  7. 70-fs mode-locked erbium-doped fiber laser with topological insulator.

    Science.gov (United States)

    Liu, Wenjun; Pang, Lihui; Han, Hainian; Tian, Wenlong; Chen, Hao; Lei, Ming; Yan, Peiguang; Wei, Zhiyi

    2016-01-27

    Femtosecond optical pulses have applications in optical communication, astronomical frequency combs, and laser spectroscopy. Here, a hybrid mode-locked erbium-doped fiber (EDF) laser with topological insulator (TI) is proposed, for the first time to our best knowledge. The pulsed laser deposition (PLD) method is employed to fabricate the fiber-taper TI saturable absorber (TISA). By virtue of the fiber-taper TISA, the hybrid EDF laser is passively mode-locked using the nonlinear polarization evolution (NPE), and emits 70 fs pulses at 1542 nm, whose 3 dB spectral width is 63 nm with a repetition rate and transfer efficiency of 95.4 MHz and 14.12%, respectively. Our experiments indicate that the proposed hybrid mode-locked EDF lasers have better performance to achieve shorter pulses with higher power and lower mode-locking threshold in the future.

  8. Suppression of thermal frequency noise in erbium-doped fiber random lasers.

    Science.gov (United States)

    Saxena, Bhavaye; Bao, Xiaoyi; Chen, Liang

    2014-02-15

    Frequency and intensity noise are characterized for erbium-doped fiber (EDF) random lasers based on Rayleigh distributed feedback mechanism. We propose a theoretical model for the frequency noise of such random lasers using the property of random phase modulations from multiple scattering points in ultralong fibers. We find that the Rayleigh feedback suppresses the noise at higher frequencies by introducing a Lorentzian envelope over the thermal frequency noise of a long fiber cavity. The theoretical model and measured frequency noise agree quantitatively with two fitting parameters. The random laser exhibits a noise level of 6  Hz²/Hz at 2 kHz, which is lower than what is found in conventional narrow-linewidth EDF fiber lasers and nonplanar ring laser oscillators (NPROs) by a factor of 166 and 2, respectively. The frequency noise has a minimum value for an optimum length of the Rayleigh scattering fiber.

  9. Switchable dual-wavelength erbium-doped fiber laser with a tilted fiber grating

    Institute of Scientific and Technical Information of China (English)

    JIN Long; KAI Gui-yun; XU Ling-ling; LIU Bo; ZHANG Jian; LIU Yan-ge; YUAN Shu-zhong; DONG Xiao-yi

    2007-01-01

    A dual-wavelength erbium doped fiber laser with a tilted fiber Bragg grating and photonic crystal fiber is proposed and demonstrated. In the laser,a 2W EDFA provides gain for all the laser lines; the highly nonlinear photonic crystal fiber introduces dynamic energy transfer between the two wavelengths caused by four wave mixing effect,so that a stable dualwavelength oscillation at room temperature is implemented. Different switching modes can be achieved by adjusting the lateral offset between the fiber grating and the guiding single mode fiber or by varying the state of polarization in the laser cavity. The maximum of output power of the laser has reached 314 mW.

  10. High Efficiency Mask Based Laser Materials Processing with TEA-CO2 - and Excimer Laser

    DEFF Research Database (Denmark)

    Bastue, Jens; Olsen, Flemmming Ove

    1997-01-01

    In general, mask based laser materials processing techniques suffer from a very low energy efficiency. We have developed a simple device called an energy enhancer, which is capable of increasing the energy efficiency of typical mask based laser materials processing systems. A short review...... line marking with TEA-CO2 laser of high speed canning lines. The second one is manufactured for marking or microdrilling with excimer laser....

  11. Near-infrared emission character of Tm3+-doped heavy metal tellurite glasses for optical amplifiers and 1.8 µm infrared laser

    Science.gov (United States)

    Lin, Hai; Wang, Xueying; Lin, Lin; Li, Changmin; Yang, Dianlai; Tanabe, Setsuhisa

    2007-06-01

    Intense 1.8 µm and efficient 1.47 µm infrared emissions have been recorded in Tm3+-doped alkali-barium-bismuth-tellurite (LKBBT) glasses with lower phonon energies under the excitation of a 792 nm diode laser. The maximum emission cross-sections for the 1.8 and 1.47 µm emission bands are derived to be 6.643 × 10-21 and 3.551 × 10-21 cm2 and the peak values are obviously higher than those in Tm3+-doped ZBLAN fluoride and TBSN tellurite glasses, respectively. In low concentration doping, the full-widths at half-maximum (FWHMs) of the two emission bands are 206 nm and 109 nm, respectively, and peak intensity ratio between them is about 2. When the doping concentration increases to 1 wt%, the peak intensity ratio exceeds 7 and the quantum efficiency of 3H4 level is only 64.6% due to the cross-relaxation process [3H4, 3H6] → [3F4, 3F4], which benefits to achieve powerful 1.8 µm emission. The efficient and broad 1.8 and 1.47 µm infrared emission bands indicate that Tm3+-doped LKBBT glasses are suitable materials in developing S- and U-band amplifiers and 1.8 µm infrared laser.

  12. Synthesis Of Materials With Infrared And Ultraviolet Lasers

    Science.gov (United States)

    Lyman, John L.

    1989-05-01

    This paper discusses three divergent examples of synthesis of materials with lasers. The three techniques are: (1) Infrared (CO2) laser synthesis of silane (SiH4) from disilane (Si2H6); (2) Excimer (ArF) laser production of fine silicon powders from methyl-and chlorosubstituted silanes; and, (3) Excimer (KrF) laser production of fine metallic powders by laser ablation. The mechanism for each process is discussed along with some conclusions about the features of the laser radiation that enable each application.

  13. Phosphate-core silica-clad Er/Yb-doped optical fiber and cladding pumped laser.

    Science.gov (United States)

    Egorova, O N; Semjonov, S L; Velmiskin, V V; Yatsenko, Yu P; Sverchkov, S E; Galagan, B I; Denker, B I; Dianov, E M

    2014-04-07

    We present a composite optical fiber with a Er/Yb co-doped phosphate-glass core in a silica glass cladding as well as cladding pumped laser. The fabrication process, optical properties, and lasing parameters are described. The slope efficiency under 980 nm cladding pumping reached 39% with respect to the absorbed pump power and 28% with respect to the coupled pump power. Due to high doping level of the phosphate core optimal length was several times shorter than that of silica core fibers.

  14. UV Laser Induced Transmission Change of Pure and Doped Silica Glass

    Institute of Scientific and Technical Information of China (English)

    XIE Junlin; DENG Tao; LUO Jie; BAN Qingrong

    2008-01-01

    Pure and F,GeO2-doped silica glass cut from fiber preforms prepared by plasma assisted chemical vapor deposition(PCVD) were investigated by ultraviolet absorption spectroscopy.The ultraviolet absorption characteristics of these glasses were also studied after UV laser irradiation and heating treatment.It was found that absorption band near 240 nm assigned to GODC was found both in GeO2-doped and F-GeO2 co-doped silica glass,but absorption intensity of the latter was lower than that of the former.It's because F can react with GODC and GeE' simultaneously and reduce their concentration.After irradiation,UV absorption change of F-GeO2 co-doped silica glass was weaker than that of GeO2-doped silica glass,it thus can be concluded that introduction of F could depress the UV absorption of GeO2-doped silica core effectively.

  15. Cr:ZnSe guided wave lasers and materials

    Science.gov (United States)

    McDaniel, Sean; Lancaster, Adam; Stites, Ronald; Thorburn, Fiona; Kar, Ajoy; Cook, Gary

    2017-02-01

    We describe a variety of technological advances in the development of efficient, powerful, and continuously tunable Cr:ZnSe lasers operating in the 2.3-2.7 μm spectral region. This includes the development of compact "single chip" waveguide Cr:ZnSe lasers, waveguide mode-locked Cr:ZnSe lasers, and the creation of homogeneously broadened laser material.

  16. Spectroscopic and luminescence characteristics of erbium doped TNZL glass for lasing materials

    Energy Technology Data Exchange (ETDEWEB)

    Assadi, A.A. [Laboratoire Géoressources, Matériaux, Environnement et Changements Globaux, Faculty of Sciences of Sfax, Sfax University, 3018 Sfax (Tunisia); Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, 07743 Jena (Germany); Damak, K., E-mail: Kamel.Damak@fss.rnu.tn [Laboratory of Radio Analysis and Environment, Sfax University, ENIS 3038 Sfax (Tunisia); Lachheb, R. [Laboratoire Géoressources, Matériaux, Environnement et Changements Globaux, Faculty of Sciences of Sfax, Sfax University, 3018 Sfax (Tunisia); Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, 07743 Jena (Germany); Herrmann, A. [Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, 07743 Jena (Germany); Yousef, E. [Department of Physics, Faculty of Sciences, Al Azhar University, Assuit Branch, Assuit (Egypt); Department of Physics, Faculty of Sciences, King Khalid University, P.O. Box 9004, Abha (Saudi Arabia); Rüssel, C. [Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, 07743 Jena (Germany); Maâlej, R. [Laboratoire Géoressources, Matériaux, Environnement et Changements Globaux, Faculty of Sciences of Sfax, Sfax University, 3018 Sfax (Tunisia)

    2015-01-25

    Highlights: • A new thermally stable tellurite glass (TNZL:Er) was synthesized by melt-quenching method. • A complete Judd–Ofelt spectroscopic evaluation of the TNZL:Er glass is presented. • A high gain coefficient and emission cross section are obtained in the 1.53 μm region. • The TNZL:Er glass would be a potential laser operation around 1.53 μm emission as well as to generate green light in color display devices. - Abstract: Rare earth-doped tellurite glasses are very attractive materials for laser and photonic applications, such as optical amplifiers. They have a good glass stability which leads to an enhancement of the radiative transition. In the present study, a new transparent bulk glass with the composition 85TeO{sub 2}–5Nb{sub 2}O{sub 5}–5ZnO–5LiF doped with 1% Er{sub 2}O{sub 3} (TNZL doped with Er{sup 3+}) was prepared by using the conventional melt-quenching method. The thermal stability and the crystallization behavior of the glass were investigated using Differential Scanning Calorimetry (DSC), X-ray diffraction and Raman spectroscopy. Furthermore, UV–vis–NIR spectra were determined. From these Judd–Ofelt parameters, Ω{sub k} (k = 2, 4, 6) of Er{sup 3+} were evaluated. The oscillator strength type transition probabilities, spectroscopic quality factors, branching ratio and radiative lifetimes of several excited states of Er{sup 3+} were predicted using intensity Judd–Ofelt parameters. The down conversion, up conversion and near infrared luminescence of the Er{sup 3+} ions in TNZL glass were investigated. Green and red emissions corresponding to ({sup 2}H{sub 11/2}, {sup 4}S{sub 3/2}) → {sup 4}I{sub 15/2} and {sup 4}F{sub 9/2} → {sup 4}I{sub 15/2} transitions were observed.

  17. Luminescence quenching in rare-earth-ion-doped $Al_2O_3$ lasers and its influence on relaxation oscillation frequency

    NARCIS (Netherlands)

    Agazzi, L.; Bernhardi, E.H.; Wörhoff, K.; Pollnau, M.

    2012-01-01

    The impact of luminescence quenching on rare-earth-ion doped lasers is investigated, and we show that the expression for the relaxation oscillation frequency needs to be modified to take the quenching properly into account.

  18. Luminescence quenching in rare-earth-ion-doped Al2O3 lasers and its influence on relaxation oscillation frequency

    NARCIS (Netherlands)

    Agazzi, L.; Bernhardi, Edward; Worhoff, Kerstin; Pollnau, Markus

    The impact of luminescence quenching on rare-earth-ion doped lasers is investigated, and we show that the expression for the relaxation oscillation frequency needs to be modified to take the quenching properly into account.

  19. Modelling the interaction of molecular hydrogen with lithium-doped hydrogen storage materials

    Science.gov (United States)

    Kolmann, Stephen J.; Chan, Bun; Jordan, Meredith J. T.

    2008-12-01

    Density functional theory (DFT) and ab initio methods are used to investigate the interaction of one, two and three hydrogen molecules with Li +-doped benzene, a model for lithium-doped carbon-based and metal organic framework materials. M05-2X is found to be the best DFT method considered, reproducing MP2 and CCSD(T) H 2 binding energies to Li +-doped benzene. The M05-2X results also agree with H 2 binding energies previously obtained in an extended model of Li atom-doped MOF-5. These calculations suggest H 2 binding in Li-doped materials is, primarily, a local interaction, implying that model compounds can be used to describe these systems.

  20. Vanderbilt free electron laser project in biomedical and materials research

    Science.gov (United States)

    Haglund, Richard F.; Tolk, N. H.

    1988-06-01

    The Medical Free Electron Laser Program was awarded to develop, construct and operate a free-electron laser facility dedicated to biomedical and materials studies, with particular emphases on: fundamental studies of absorption and localization of electromagnetic energy on and near material surfaces, especially through electronic and other selective, non-statistical processes; non-thermal photon-materials interactions (e.g., electronic bond-breaking or vibrational energy transfer) in physical and biological materials as well as in long-wavelength biopolymer dynamics; development of FEL-based methods to study drug action and to characterize biomolecular properties and metabolic processes in biomembranes; clinical applications in otolaryngology, neurosurgery, ophthalmology and radiology stressing the use of the laser for selective laser-tissue, laser-cellular and laser-molecule interactions in both therapeutic and diagnostic modalities.

  1. Wear behaviour of laser melted an ion implanted materials.

    NARCIS (Netherlands)

    Beurs, Hans de

    1988-01-01

    The emphasis in this thesis is on the development of wear resistant materials by laser melting. Furthermore, the principle aim is to search for the dislocation characteristics common to the wear process in heterogeneous materials. ... Zie: Summary

  2. Laser and nonlinear optical materials: SPIE volume 681

    Energy Technology Data Exchange (ETDEWEB)

    De Shazer, L.G.

    1987-01-01

    This book contains papers arranged under the following session headings: Nonlinear optical crystals; Laser host crystals; Electro-optic and magneto-optic materials; and Characterization of optical materials.

  3. XRD Analysis on the Fluorescence Material of Sm Doped Si-Ca-Mg System

    Institute of Scientific and Technical Information of China (English)

    HUANG Qing-Ming

    2007-01-01

    Fluorescence material of Sm doped Si-Ca-Mg system was synthesized by using the method of solid phase reaction at high temperature. The phase composition and crystal structure of this material were analyzed with XRD method for its composition and the existence form of Sm atom. We aimed to exactly determine the phase composition of this fluorescence material and the doping position and environment of rare-earth Sm atom in the system because these factors have significant effects on the properties. The analytical results show that the Sm atoms dope in Ca2O26Si6Sm8 lattice in the form of atomic site-occupation in three different space positions with different occupancy rates. Therefore, based on the XRD analytical results, the fluorescence material of Sm doped Si-Ca-Mg system with high performance can be synthesized.

  4. Large Mode Area Yb-Doped Photonic Bandgap Fiber Lasers

    Science.gov (United States)

    2015-02-08

    effective area of 1450 ?m2 was fabricated using the stack and draw technique (Figure 1). The microstructures in the cladding are comprised of germanium...doped silica. A low refractive index polymer coating provides a numerical aperture of 0.46 for pumping purposes. 1. REPORT DATE (DD-MM-YYYY) 4...and a calculated effective area of 1450 ?m2 was fabricated using the stack and draw technique (Figure 1). The microstructures in the cladding are

  5. Pulsed laser annealing of highly doped Ge:Sb layers deposited on different substrates

    Science.gov (United States)

    Batalov, R. I.; Bayazitov, R. M.; Faizrakhmanov, I. A.; Lyadov, N. M.; Shustov, V. A.; Ivlev, G. D.

    2016-10-01

    Germanium (Ge) is a promising material for micro- and optoelectronics to produce high speed field-effect transistors, photodetectors, light-emitting diodes and lasers. For such applications tensile-strained and/or highly n-doped Ge layers are needed. The authors have performed the formation of such layers by ion-beam sputtering of composite Sb/Ge target, deposition of thin amorphous Ge:Sb films (~200 nm thick) on different substrates (c-Si, c-Al2O3, α-SiO2) followed by pulsed laser annealing (PLA) for their crystallization and Sb dopant activation. Structural, electrical and optical characterization of Ge:Sb films was carried out using scanning electron microscopy, x-ray diffraction, micro-Raman spectroscopy, secondary ion mass spectrometry methods and by measuring sheet resistance, carrier concentration and photoluminescence. The obtained polycrystalline n-Ge:Sb layers (N Sb ~ 1 at.%) are characterized by increased values of tensile strain (up to 1%) and homogenious Sb dopant distribution within layer thickness. The electrical measurements at 300 K revealed the low sheet resistance (up to 40 Ω/□) and extremely high electron concentration (up to 5.5  ×  1020 cm-3) in Ge:Sb/SiO2 samples that indicated full electrical activation of Sb dopant on SiO2 substrate. The increased values of tensile strain and electron concentration of Ge:Sb films on α-SiO2 are explained by low values of thermal conductivity and thermal expansion coefficients of quartz substrate.

  6. Laser Processing of High-Tech Materials at High Irradiance.

    Science.gov (United States)

    1987-05-13

    CHARGED PARTICLES (Electrons, Ions, Plasma) * "PHOTONS LASER IMPULSE VAPOR SPALLATION CRATER SHOCK WAVE THERMAL WAVE Fig. I - Interaction of a high...metals. 2ŗ𔃾 Shaping includes drilling , cutting, bending, laser assisted machining (turning and milling) and direct laser machining. Joining includes...induces a tensile stress which can be sufficient to exceed the material’s strength. This dynamic fracture of material is called spallation . Although

  7. Design of erbium doped double clad ZBLAN Fibre laser

    Science.gov (United States)

    Oladeji, A.; Phillips, A.; Lamrini, S.; Scholle, K.; Fuhrberg, P.; Seddon, A. B.; Benson, T. M.; Sujecki, S.

    2015-06-01

    A high powered octagonal double clad ZBLAN (33 μm/330 μm, NA=0.13) glass fibre for mid-infrared light generation is studied using a one dimensional rate equation model. The fibre laser design employs the concept of cascade lasing and includes up-conversion phenomena. The results obtained demonstrate that efficient cascade lasing may be achieved in practice without the need for fibre grating fabrication, as a sufficient level of feedback for laser action is provided by Fresnel light reflection at ZBLAN glass fibre air interfaces. Further enhancement of the laser efficiency can be achieved by terminating one of the fibre ends with a mirror. Simulation results show that the laser operation with 20 W of pump power at 0.98 μm wavelength can be achieved at 2.75 μm operating wavelength with Er3+ ion concentrations of 60,000 ppm.

  8. Laser Processing of Materials Fundamentals, Applications and Developments

    CERN Document Server

    Schaaf, Peter

    2010-01-01

    Laser materials processing has made tremendous progress and is now at the forefront of industrial and medical applications. The book describes recent advances in smart and nanoscaled materials going well beyond the traditional cutting and welding applications. As no analytical methods are described the examples are really going into the details of what nowadways is possible by employing lasers for sophisticated materials processing giving rise to achievements not possible by conventional materials processing.

  9. A Polarization Controlled Switchable Multiwavelength Erbium-Doped Fibre Laser

    Institute of Scientific and Technical Information of China (English)

    冯新焕; 刘艳格; 孙磊; 袁树忠; 开桂云; 董孝义

    2004-01-01

    A polarization controlled switchable multiwavelength erbium-dopedfibre laser with overlapping cavities is proposed. The wavelengths are specified by two Bragg gratings in polarization-maintaining PANDA fibre. The proposed laser can be designed to be operated in stable four-wavelength or wavelength switching modes only by simple adjustment of two polarization controllers. For wavelength switching, four single-wavelength, six dualwavelength, and four three-wavelength operations have been obtained. The minimum wavelength spacing is only about 0.4 nm.

  10. Liquid Contact Luminescence from Semiconductor Laser Materials

    Science.gov (United States)

    1997-01-09

    Luminescence - Diagnostic As a diagnostic tool, LCL can provide much useful information about the quality of the epitaxial wafer prior to laser fabrication . In...diagnostic tool, LCL can provide a variety of useful information about the quality of the epitaxial wafer prior to laser fabrication . Temporal...the quality of the epitaxial laser wafer prior to laser fabrication . It is a quick, inexpensive, and non- destructive process that measures a variety

  11. Multiphysical Simulation of Laser Material Processing

    Science.gov (United States)

    Otto, Andreas; Koch, Holger; Vazquez, Rodrigo Gomez

    Within this paper a multiphysical simulation model is presented that is capable for simulating a wide range of laser processes like e.g. laser beam welding, brazing, cutting, drilling or ablation. Some important aspects of the model are explained more in detail and results from test cases are compared with analytical solutions revealing the high accuracy of the model. Finally exemplary results from process simulations on laser beam remote cutting of steel and laser beam scribing of silicon wafers are given.

  12. Comparative physical, chemical and biological assessment of simple and titanium-doped ovine dentine-derived hydroxyapatite coatings fabricated by pulsed laser deposition

    Science.gov (United States)

    Duta, L.; Mihailescu, N.; Popescu, A. C.; Luculescu, C. R.; Mihailescu, I. N.; Çetin, G.; Gunduz, O.; Oktar, F. N.; Popa, A. C.; Kuncser, A.; Besleaga, C.; Stan, G. E.

    2017-08-01

    We report on the synthesis by Pulsed Laser Deposition of simple and Ti doped hydroxyapatite thin films of biological (ovine dentine) origin. Detailed physical, chemical, mechanical and biological investigations were performed. Morphological examination of films showed a surface composed of spheroidal particulates, of micronic size. Compositional analyses pointed to the presence of typical natural doping elements of bone, along with a slight non-stoichiometry of the deposited films. Structural investigations proved the monophasic hydroxyapatite nature of both simple and Ti doped films. Ti doping of biological hydroxyapatite induced an overall downgrade of the films crystallinity together with an increase of the films roughness. It is to be emphasized that bonding strength values measured at film/Ti substrate interface were superior to the minimum value imposed by International Standards regulating the load-bearing implant coatings. In vitro tests on Ti doped structures, compared to simple ones, revealed excellent biocompatibility in human mesenchymal stem cell cultures, a higher proliferation rate and a good cytocompatibility. The obtained results aim to elucidate the overall positive role of Ti doping on the hydroxyapatite films performance, and demonstrate the possibility to use this novel type of coatings as feasible materials for future implantology applications.

  13. Highly doped InP as a low loss plasmonic material for mid-IR region

    DEFF Research Database (Denmark)

    Panah, Mohammad Esmail Aryaee; Takayama, Osamu; Morozov, S. V.

    2016-01-01

    We study plasmonic properties of highly doped InP in the mid-infrared (IR) range. InP was grown by metal-organic vapor phase epitaxy (MOVPE) with the growth conditions optimized to achieve high free electron concentrations by doping with silicon. The permittivity of the grown material was found...... by the excitation of surface plasmon-polaritons in a periodically structured epilayer. Characterization shows good agreement between the theory and experimental results and confirms that highly doped InP is an effective plasmonic material aiming it for applications in the mid-IR wavelength range....

  14. Fullerene-doped porous glasses

    Science.gov (United States)

    Joshi, M. P.; Kukreja, L. M.; Rustagi, K. C.

    We report the doping of C60 in porous glass by diffusion in solution phase at room temperature. The presence of C60 in the doped porous glass was confirmed spectroscopically. We also report the changes in optical absorption spectrum and intensity-dependent transmission of 30 ns laser pulses at 527 nm in these materials.

  15. Fullerene-doped porous glasses

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, M.P. [Center for Adv. Technol., Indore (India). Nonlinear Optics Group; Kukreja, L.M. [Center for Adv. Technol., Indore (India). Nonlinear Optics Group; Rustagi, K.C. [Center for Adv. Technol., Indore (India). Nonlinear Optics Group

    1997-07-01

    We report the doping of C{sub 60} in porous glass by diffusion in solution phase at room temperature. The presence of C{sub 60} in the doped porous glass was confirmed spectroscopically. We also report the changes in optical absorption spectrum and intensity-dependent transmission of 30 ns laser pulses at 527 nm in these materials. (orig.)

  16. Red luminescence of Eu{sup 3+} doped ZnO nanoparticles fabricated by laser ablation in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Katsuki, Daichi; Sato, Toshiyuki; Suzuki, Ryoji; Nanai, Yasushi; Okuno, Tsuyoshi [University of Electro-Communications, Department of Engineering Science, Tokyo (Japan); Kimura, Seiji [University of Electro-Communications, Center for Instrumental Analysis, Tokyo (Japan)

    2012-08-15

    Fabrication of Eu{sup 3+}-doped ZnO nanoparticles by laser ablation in liquid medium is reported. Sintered disks made of mixed powders of ZnO and Eu{sub 2}O{sub 3} are used for targets, and surfactant of sodium dodecyl sulfate or LiOH is included in solution. Round-shaped nanoparticles with the diameter of 5{proportional_to}30 nm are synthesized. When the ZnO host is photoexcited, broad green photoluminescence (PL) of oxygen vacancies in the ZnO host as well as red PL of Eu{sup 3+} is observed at room temperature. The red PL peak of Eu{sup 3+} included in the ZnO host lattice is different from that of the source material of Eu{sub 2}O{sub 3}. Energy transfer from the ZnO host to Eu{sup 3+} is demonstrated in site-selectively excited PL spectra and its excitation spectra. This result shows that the liquid-phase laser ablation is useful for doping active centers into nanoparticles. (orig.)

  17. Solid-like ablation propulsion generation in nanosecond pulsed laser interaction with carbon-doped glycerol

    Science.gov (United States)

    Zheng, Zhi-Yuan; Zhang, Si-Qi; Liang, Tian; Qi, Jing; Tang, Wei-Chong; Xiao, Ke; Gao, Lu; Gao, Hua; Zhang, Zi-Li

    2017-03-01

    A solid-like propellant of carbon-doped glycerol ablated by a nanosecond pulsed laser is investigated. The results show that the specific impulse increases with increasing carbon content, and a maximum value of 228 s is obtained. The high specific impulse is attributed to the low ablated mass loss that occurs at high carbon content. More importantly, with increasing carbon content, the properties of the doped glycerol approach to those of a solid. These results indicate that propulsion at the required coupling coefficient and specific impulse can be realized by doping a liquid propellant with an absorber. Project supported by the Fundamental Research Funds for the Central Universities, China (Grant Nos. 53200859165 and 2562010050).

  18. State-of-the-art of laser materials processing; Saikin no laser kakono genjo

    Energy Technology Data Exchange (ETDEWEB)

    Kutsuna, M. [Nagoya University, Nagoya (Japan)

    1999-12-31

    The use of laser in the field of materials processing is stated. For the processing of materials, devices have been developed for CO2 laser, YAG (Yttrium Aluminum Garnet) laser, excimer laser, and semiconductor laser. A 45kW output CO2 laser device and a 10kW YAG laser device are already on the market, and research and development is in progress for processes still higher in efficiency. The welding of 30-40mm thick steel slabs is already in actual use, with the aid of a 45kW CO2 laser device. In the field of cutting, a 6kW device has come into use in ship building and bridge construction and in steel frame fabrication. The progress of YAG laser development is remarkable, and a flexible manufacturing system has been constructed using 0.6mm diameter optical fibers. The system is about to be utilized in the automobile industry etc. Diode laser devices capable of 2.5kW have been developed in Germany and America, which will be installed on robot arm tips for application to 3-dimensional laser processing. Kawasaki Heavy Industries, Ltd., has developed a 10kW chemical iodine laser, which is a YAG device excited by a laser diode. Described in the text are the characteristics of laser-aided processing, kinds of laser-aided processing, applications in industrial fields, etc. (NEDO)

  19. Study of mechanism of strengthening materials with laser shock processing

    Institute of Scientific and Technical Information of China (English)

    郭大浩; 吴鸿兴; 王声波; 洪昕; 王劼; 戴宇生; 夏小平; 张永康; 张宏; 唐亚新; 余承业

    1999-01-01

    The material of surface layer absorbs the energy of laser and produces plasma, when the high power laser radiates the surface of material. The plasma blows up and produces an intense shock wave. When the surface of material is covered with a confining medium and an absorptive coating layer, the shock wave can be strengthened greatly. There-fore a huge momentum is exerted on the surface of material. There is a plastic deformation layer in the material when the shock stress exceeds the dynamic yield strength of material. Due to the residual compressive stress, the high density of dislocation in the plastic layer, the anti-fatigue life of material is prolonged.

  20. High-efficiency Tm-doped yttrium aluminum garnet laser pumped with a wavelength-locked laser diode

    Science.gov (United States)

    Huang, H. Z.; Huang, J. H.; Liu, H. G.; Dai, S. T.; Weng, W.; Zheng, H.; Ge, Y.; Li, J. H.; Deng, J.; Yang, X.; Lin, W. X.

    2016-09-01

    We first demonstrate a high-efficiency composite Tm-doped yttrium aluminum garnet laser end-pumped with a narrow-linewidth laser diode, which was locked at a wavelength of 784.9 nm with volume Bragg gratings. The locked pump wavelength was experimentally determined by the excitation peak, which was also the absorption peak of a 3.5 at.% Tm:YAG crystal around 785 nm, for the improvement of laser efficiency under high-intensity pumping. Under an absorbed pump power of 24.64 W, a maximum output power of 11.12 W at 2018 nm was obtained, corresponding to an optical to optical conversion efficiency of 45.1% and a slope efficiency of 52.4%.

  1. Thermal degradation of ultrabroad bismuth NIR luminescence in bismuth-doped tantalum germanate laser glasses.

    Science.gov (United States)

    Wang, Liping; Zhao, Yanqi; Xu, Shanhui; Peng, Mingying

    2016-04-01

    Because of ultra-broadband luminescence in 1000-1700 nm and consequent applications in fiber amplifier and lasers in the new spectral range where traditional rare earth cannot work, bismuth-doped laser glasses have received rising interest recently. For long-term practical application, thermal degradation must be considered for the glasses. This, however, has seldom been investigated. Here we report the thermal degradation of bismuth-doped germanate glass. Heating and cooling cycle experiments at high temperature reveal strong dependence of the thermal degradation on glass compositions. Bismuth and tantalum lead to the reversible degradation, while lithium can produce permanent irreversible degradation. The degradation becomes worse as lithium content increases in the glass. Absorption spectra show this is due to partial oxidation of bismuth near-infrared emission center. Surprisingly, we notice the emission of bismuth exhibits blueshift, rather than redshift at a higher temperature, and the blueshift can be suppressed by increasing the lithium content.

  2. A Room-Temperature Multiwavelength Erbium-Doped Fibre Laser by Exploiting Polarization Hole Burning

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao; DONG Xiao-Yi; XIONG Ling-Yun; DOU Qing-Ying; LI Yao; YU Ling; LIU Yan-Ge; LIU Li-Hui; YUAN Shu-Zhong; KAI Gui-Yun

    2005-01-01

    @@ Multiwavelength operation of a linear cavity erbium-doped fibre laser (EDFL) is proposed and demonstrated. A 3-dB fibre loop mirror and a high birefringence (HiBi) fibre loop mirror are utilized as the cavity reflectors. By utilizing the wavelength-dependent polarization rotation induced by the HiBi fibre loop mirror and by using a fibre polarizer to control the intracavity polarization state, the polarization states of different wavelengths arediversified. Therefore, the polarization hole burning (PHB) effect has been greatly enhanced and the homogeneous broadening of erbium-doped fibre is suppressed to a large extent. By simply tuning a polarization controller, we experimentally obtained simultaneous lasing of four and five wavelengths with wavelength spacing of ~1.8nm and less than 2nm at room temperature, respectively. The repeated scans show that all of these lasers have good stability.

  3. Highly stable graphene-assisted tunable dual-wavelength erbium-doped fiber laser.

    Science.gov (United States)

    Ahmad, Harith; Latif, Amirah Abdul; Abdul Khudus, Muhammad Imran Mustafa; Zulkifli, Ahmad Zarif; Zulkifli, Mohd Zamani; Thambiratnam, Kavintheran; Harun, Sulaiman Wadi

    2013-02-01

    A highly stable tunable dual-wavelength fiber laser (TDWFL) using graphene as a means to generate a highly stable output is proposed and generated. The TDWFL comprises a 1 m long, highly doped erbium-doped fiber (EDF) acting as the linear gain medium, with a 24-channel arrayed waveguide grating acting as a wavelength slicer as well as a tuning mechanism to generate different wavelength pairs. The tuned wavelength pairs can range from 0.8 to 18.2 nm. A few layers of graphene are incorporated into the laser cavity to induce the four-wave-mixing effect, which stabilizes the dual-wavelength output by suppressing the mode competition that arises as a result of homogenous broadening in the EDF.

  4. C-band wavelength-swept single-longitudinalmode erbium-doped fiber ring laser.

    Science.gov (United States)

    Zhang, Kang; Kang, Jin U

    2008-09-01

    A wavelength-swept single-longitudinal-mode erbium-doped fiber ring laser capable of operating at sweeping frequency in the order of a few kHz is designed and demonstrated by using a fiber Fabry-Perot tunable filter and a Sagnac loop incorporated with a 3.5-meter unpumped erbium-doped fiber. The laser operates in continuous-wave (CW) mode and can sweep approximately 45 nm over the entire C-band (1520nm-1570nm) window with linewidth less than 0.7 kHz. The optimum wavelength sweeping frequency in order to achieve the best output power stability was found to be approximately20Hz with sweeping-induced power fluctuation of only 0.1%.

  5. Ultra High p-doping Material Research for GaN Based Light Emitters

    Energy Technology Data Exchange (ETDEWEB)

    Vladimir Dmitriev

    2007-06-30

    The main goal of the Project is to investigate doping mechanisms in p-type GaN and AlGaN and controllably fabricate ultra high doped p-GaN materials and epitaxial structures. Highly doped p-type GaN-based materials with low electrical resistivity and abrupt doping profiles are of great importance for efficient light emitters for solid state lighting (SSL) applications. Cost-effective hydride vapor phase epitaxial (HVPE) technology was proposed to investigate and develop p-GaN materials for SSL. High p-type doping is required to improve (i) carrier injection efficiency in light emitting p-n junctions that will result in increasing of light emitting efficiency, (ii) current spreading in light emitting structures that will improve external quantum efficiency, and (iii) parameters of Ohmic contacts to reduce operating voltage and tolerate higher forward currents needed for the high output power operation of light emitters. Highly doped p-type GaN layers and AlGaN/GaN heterostructures with low electrical resistivity will lead to novel device and contact metallization designs for high-power high efficiency GaN-based light emitters. Overall, highly doped p-GaN is a key element to develop light emitting devices for the DOE SSL program. The project was focused on material research for highly doped p-type GaN materials and device structures for applications in high performance light emitters for general illumination P-GaN and p-AlGaN layers and multi-layer structures were grown by HVPE and investigated in terms of surface morphology and structure, doping concentrations and profiles, optical, electrical, and structural properties. Tasks of the project were successfully accomplished. Highly doped GaN materials with p-type conductivity were fabricated. As-grown GaN layers had concentration N{sub a}-N{sub d} as high as 3 x 10{sup 19} cm{sup -3}. Mechanisms of doping were investigated and results of material studies were reported at several International conferences providing

  6. Cutting of nonmetallic materials using Nd:YAG laser beam

    Institute of Scientific and Technical Information of China (English)

    Bashir Ahmed Tahir; Rashid Ahmed; M. G. B. Ashiq; Afaq Ahmed; M. A. Saeed

    2012-01-01

    This study deals with Nd:YAG laser cutting nonmetallic materials,which is one of the most important and popular industrial applications of laser.The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed.For approximate cutting depth,a theoretical study is conducted in terms of material property and cutting speed.Results show a nonlinear relation between the cutting depth and input energy.There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s.An extra energy is utilized in the deep cutting.It is inferred that as the laser power increases,cutting depth increases.The experimental outcomes are in good agreement with theoretical results.This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting,scribing,trimming,engraving,and marking nonmetallic materials.

  7. Gas-self-filter-based erbium-doped fiber loop laser for gas detection.

    Science.gov (United States)

    Guo, Kaikai; Lou, Xiutao; Yan, Chunsheng; Mei, Liang

    2014-08-01

    An erbium-doped fiber (EDF) loop laser, based on a gas-self-filter (GSF), is developed with single or multiple wavelength emission. The GSF is a type of Mach-Zehnder interferometer with a gas cell in one arm. By matching the destructive wavelength of the interferometer with the gas absorption line, the self-filtering function is achieved. A GSF-based multi-wavelength laser with a side-mode suppression ratio of ~50  dB is performed. As an example, C₂H₂ gas is detected using a single-wavelength GSF-based laser with correlation spectroscopy, and a good linearity of the measurement is obtained. The present laser has the potential advantage for multiple gas detection, e.g., being free of wavelength calibration.

  8. Switchable multiwavelength fiber laser using erbium-doped twin-core fiber and nonlinear polarization rotation

    Science.gov (United States)

    Lian, Yudong; Ren, Guobin; Zhu, Bofeng; Gao, Yixiao; Jian, Wei; Ren, Wenhua; Jian, Shuisheng

    2017-05-01

    We propose and demonstrate a switchable multiwavelength fiber laser using erbium-doped twin-core fiber (ED-TCF) and nonlinear polarization rotation (NPR). The number switchability of lasing wavelengths being switched from 1 to 4 and wavelength location switchability could be achieved simultaneously in the proposed configuration with a wavelength spacing of 1.1 nm and an optical signal to noise ratio (OSNR) larger than 43 dB. The output laser powers at different wavelengths are nearly the same with a fluctuation less than 2 dB. The proposed fiber laser shows good stability with wavelength shift within 0.01 nm and peak power fluctuation less than 5 dB. The proposed fiber laser has the advantages of simple structure and stable operation.

  9. Submicrojoule femtosecond erbium-doped fibre laser for the generation of dispersive waves at submicron wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Kotov, L V [Moscow Institute of Physics and Technology (State University), Dolgoprudnyi, Moscow Region (Russian Federation); Koptev, M Yu; Anashkina, E A; Muravyev, S V; Andrianov, A V; Kim, A V [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation); Bubnov, M M; Likhachev, M E [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Ignat' ev, A D [' ' FORC - Photonics' ' Group, Moscow (Russian Federation); Lipatov, D S; Gur' yanov, A N [G.G.Devyatykh Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

    2014-05-30

    We have demonstrated a femtosecond erbium-doped fibre laser system built in the master oscillator/power amplifier (MOPA) approach. The final amplifier stage utilises a specially designed large mode area active fibre cladding-pumped by multimode laser diodes. The system is capable of generating submicrojoule pulses at a wavelength near 1.6 μm. We have obtained 530-fs pulses with an energy of 400 nJ. The output of the system can be converted to wavelengths shorter than 1 μm through the generation of dispersive waves in passive nonlinear fibre. We have obtained ultra-short 7-nJ pulses with a spectral width of ∼100 nm and a centre wavelength of 0.9 μm, which can be used as a seed signal in parametric amplifiers in designing petawatt laser systems. (lasers)

  10. Blue surface-emitting distributed feedback lasers based on TPD-doped films.

    Science.gov (United States)

    Calzado, Eva M; Villalvilla, Jose M; Boj, Pedro G; Quintana, Jose A; Postigo, Pablo A; Díaz-García, María A

    2010-01-20

    Single-mode second-order distributed feedback (DFB) lasers with low threshold, based on polystyrene films doped with 30 wt. % of the hole-transporting organic molecule N,N'-bis (3-methylphenyl)-N,N'-diphenylbenzidine (TPD) are reported. The laser emission wavelength was tuned between 415 and 427 nm by film thickness variation. The effectiveness of the DFB grating in improving the laser performance is evidenced by the observation of linewidths and laser thresholds lower than those of the amplified spontaneous emission characteristics shown by films without gratings. The use of holographic lithography as the technique for grating recording has allowed us to prepare large samples in a fast, versatile, and simple manner.

  11. Proton acceleration using doped Argon plasma density gradient interacting with relativistic CO2 -laser pulse

    Science.gov (United States)

    Sahai, Aakash; Ettlinger, Oliver; Hicks, George; Ditter, Emma-Jane; Najmudin, Zulfikar

    2016-10-01

    We investigate proton and light-ion acceleration driven by the interaction of relativistic CO2 laser pulses with overdense Argon or other heavy-ion gas targets doped with lighter-ion species. Optically shaping the gas targets allows tuning of the pre-plasma scale-length from a few to several laser wavelengths, allowing the laser to efficiently drive a propagating snowplow through the bunching in the electron density. Preliminary PIC-based modeling shows that the lighter-ion species is accelerated even without any significant motion of the heavier ions which is a signature of the Relativistically Induced Transparency Acceleration mechanism. Some outlines of possible experiments at the TW CO2 laser at the Accelerator Test Facility at Brookhaven National Laboratory are presented.

  12. Femtosecond laser-induced color change and filamentation in Ag+-doped silicate glass

    Institute of Scientific and Technical Information of China (English)

    Haiyi Sun; Fei He; Jian Xu; Yang Liao; Ya Cheng; Zhizhan Xu; Xiongwei Jiang; Ye Dai

    2009-01-01

    We investigate the influence of multiple filamentation (MF) on the micromachining in Ag+-doped silicate glass irradiated by a 1-kHz femtosecond laser. The thresholds of MF and color change (CC) are measured for both linearly and circularly polarized laser beams. The results demonstrate that the thresholds of MF and CC are very close. The thresholds of CC and MF for circular polarization increase by ~1.4 times compared with linear polarization. Circular polarization can suppress the number of filaments to some extent compared with linear polarization. However, it is difficult to obtain CC without any filamentation if circular polarization technique is used alone.

  13. Poor fluorinated graphene sheets carboxymethylcellulose polymer composite mode locker for erbium doped fiber laser

    Science.gov (United States)

    Mou, Chengbo; Arif, Raz; Lobach, Anatoly S.; Khudyakov, Dmitry V.; Spitsina, Nataliya G.; Kazakov, Valery A.; Turitsyn, Sergei; Rozhin, Aleksey

    2015-02-01

    We report poor fluorinated graphene sheets produced by thermal exfoliation embedding in carboxymethylcellulose polymer composite (GCMC) as an efficient mode locker for erbium doped fiber laser. Two GCMC mode lockers with different concentration have been fabricated. The GCMC based mode locked fiber laser shows stable soliton output pulse shaping with repetition rate of 28.5 MHz and output power of 5.5 mW was achieved with the high concentration GCMC, while a slightly higher output power of 6.9 mW was obtained using the low concentration GCMC mode locker.

  14. Widely tunable Tm-doped mode-locked all-fiber laser

    Science.gov (United States)

    Yan, Zhiyu; Sun, Biao; Li, Xiaohui; Luo, Jiaqi; Shum, Perry Ping; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2016-06-01

    We demonstrated a widely tunable Tm-doped mode-locked all-fiber laser, with the widest tunable range of 136 nm, from 1842 to 1978 nm. Nonlinear polarization evolution (NPE) technique is employed to enable mode-locking and the wavelength-tunable operation. The widely tunable range attributes to the NPE-induced transmission modulation and bidirectional pumping mechanism. Such kind of tunable mode-locked laser can find various applications in optical communications, spectroscopy, time-resolved measurement, and among others.

  15. Switchable and spacing-tunable dual-wavelength erbium-doped fibre lasers

    Institute of Scientific and Technical Information of China (English)

    Feng Xin-Huan; Liu Yan-Ge; Sun Lei; Yuan Shu-Zhong; Kai Gui-Yun; Dong Xiao-Yi

    2005-01-01

    Two switchable and spacing-tunable dual-wavelength linear cavity erbium-doped fibre lasers are demonstrated experimentally. One of them utilizes a Bragg grating in polarization-maintained PANDA fibre and the other uses a Bragg grating in standard single mode fibre for wavelength selection. Both exploit the birefringence characteristics of the FBG induced by transverse strain. The proposed lasers can be made to operate in stable dual-wavelength or switch between two wavelengths at room temperature just by simple adjustment of a polarization controller. Transverse strain loading on the FBG allows the wavelength spacing to be controlled.

  16. Poor fluorinated graphene sheets carboxymethylcellulose polymer composite mode locker for erbium doped fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Mou, Chengbo, E-mail: mouc1@aston.ac.uk, E-mail: a.rozhin@aston.ac.uk; Turitsyn, Sergei; Rozhin, Aleksey, E-mail: mouc1@aston.ac.uk, E-mail: a.rozhin@aston.ac.uk [Aston Institute of Photonic Technologies, Aston University, Aston Triangle, Birmingham B4 7ET (United Kingdom); Arif, Raz [Aston Institute of Photonic Technologies, Aston University, Aston Triangle, Birmingham B4 7ET (United Kingdom); Physics Department, Faculty of Science, University of Sulaimani, Sulaimani, Kurdistan Region (Iraq); Lobach, Anatoly S.; Spitsina, Nataliya G. [Institute of Problems of Chemical Physics RAS, Ac. Semenov Av. 1, Chernogolovka, Moscow Region 142432 (Russian Federation); Khudyakov, Dmitry V. [Institute of Problems of Chemical Physics RAS, Ac. Semenov Av. 1, Chernogolovka, Moscow Region 142432 (Russian Federation); Physics Instrumentation Center of the Institute of General Physics A.M. Prokhorov Russian Academy of Sciences, Troitsk, Moscow Region 142190 (Russian Federation); Kazakov, Valery A. [Keldysh Center, Onezhskaya 8, Moscow 125438 (Russian Federation)

    2015-02-09

    We report poor fluorinated graphene sheets produced by thermal exfoliation embedding in carboxymethylcellulose polymer composite (GCMC) as an efficient mode locker for erbium doped fiber laser. Two GCMC mode lockers with different concentration have been fabricated. The GCMC based mode locked fiber laser shows stable soliton output pulse shaping with repetition rate of 28.5 MHz and output power of 5.5 mW was achieved with the high concentration GCMC, while a slightly higher output power of 6.9 mW was obtained using the low concentration GCMC mode locker.

  17. GHz high power Yb-doped picosecond fiber laser and supercontinuum generation.

    Science.gov (United States)

    Gao, Jing; Ge, Tingwu; Li, Wuyi; Kuang, Hongshen; Wang, Zhiyong

    2014-12-20

    We demonstrated a 97 W all-fiber picosecond master oscillator power amplifier seeding by an actively harmonic mode-locked Yb-doped fiber laser. The laser seed pulse duration was 7.7 ps at a 1.223 GHz repetition rate with a central wavelength of 1062 nm. In addition, by launching the amplified pulses into a 5 m long photonic crystal fiber, we obtained a 41.8 W supercontinuum covering the wavelength from 600 to 1700 nm with a 10 dB bandwidth of 1040 nm.

  18. Pulsed Laser Deposition of Er doped tellurite films on large area

    Energy Technology Data Exchange (ETDEWEB)

    Bouazaoui, M [Laboratoire PhLAM, UMR 8523, Groupe Photonique, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France); Capoen, B [Laboratoire PhLAM, UMR 8523, Groupe Photonique, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France); Caricato, A P [L3 group, Dipartimento di Fisica, Lecce, Via Arnesano, 73100 Lecce (Italy); Chiasera, A [CNR-IFN, CSMFO group, via Sommarive 14, 38100 Povo-Trento (Italy); Fazzi, A [L3 group, Dipartimento di Fisica, Lecce, Via Arnesano, 73100 Lecce (Italy); Ferrari, M [CNR-IFN, CSMFO group, via Sommarive 14, 38100 Povo-Trento (Italy); Leggieri, G [L3 group, Dipartimento di Fisica, Lecce, Via Arnesano, 73100 Lecce (Italy); Martino, M [L3 group, Dipartimento di Fisica, Lecce, Via Arnesano, 73100 Lecce (Italy); Mattarelli, M [Physics Department, CSMFO group, via Sommarive 14, 38100 Povo-Trento (Italy); Montagna, M [Physics Department, CSMFO group, via Sommarive 14, 38100 Povo-Trento (Italy); Romano, F [L3 group, Dipartimento di Fisica, Lecce, Via Arnesano, 73100 Lecce (Italy); Tunno, T [L3 group, Dipartimento di Fisica, Lecce, Via Arnesano, 73100 Lecce (Italy); Turrel, S [Universite des Sciences et Technologies de Lille, Laboratoire de Spectrochimie Infrarouge et Raman, LASIR - UMR 8516 du CNRS - Bat C5 - 59655 - Villeneuve d' Ascq cedex (France); Vishnubhatla, K [Physics Department, CSMFO group, via Sommarive 14, 38100 Povo-Trento (Italy)

    2007-04-15

    Thin films of Er{sup 3+}-doped tungsten tellurite glass have been prepared by the pulsed laser deposition technique using an ArF excimer laser. The depositions were performed at different O{sub 2} pressure (5, 10 Pa) and at different substrate temperatures (RT, 100deg. C and 200deg. C). The composition and the optical properties of the deposited films, such as transmission, dispersion curves of refraction index and extinction coefficient, and film thickness were studied for the different deposition parameters. Transparent films at the highest substrate temperature were obtained only for a higher oxygen pressure with respect to the RT conditions.

  19. Multi-wavelength laser generation with Bismuthbased Erbium-doped fiber.

    Science.gov (United States)

    Ahmad, H; Shahi, S; Harun, S W

    2009-01-05

    A multi-wavelength laser comb is demonstrated using a nonlinear effect in a backward pumped Bismuth-based Erbium-doped fiber (Bi-EDF) for the first time. It uses a ring cavity resonator scheme containing a 215 cm long highly nonlinear Bi-EDF, optical isolators, polarisation controller and 10 dB output coupler. The laser generates more than 10 lines of optical comb with a line spacing of approximately 0.41 nm at 1615.5 nm region using 146 mW of 1480 nm pump power.

  20. Figure-eight actively-passively mode-locked erbium-doped fiber laser

    Science.gov (United States)

    Wang, Zhaoying; Yu, Zhenhong; Ge, Chunfeng; Zhang, Ruifeng; Jia, Dongfang; Li, Shichen

    2003-03-01

    The advantages of using nonlinear optical loop mirror (NOLM) to compress pulse with slight amplitude fluctuation and reflected energy loss are analyzed in theory. Experimentally the NOLM is placed in an actively mode-locked erbium-doped fiber ring laser to form a figure-eight actively and passively modelocked fiber laser. 12 ps mode-locked pulses centered at 1.543 ?m were obtained with the modulation frequency of 2.498748700 GHz. 3.715 mW output power is achieved with 50 mW pump power.

  1. Linearly polarized intracavity passive Q-switched Yb-doped photonic crystal fibre laser

    Indian Academy of Sciences (India)

    Usha Chakravarty; Antony Kuruvilla; Rajpal Singh; B N Upadhyay; K S Bindra; S M Oak

    2014-02-01

    In this paper we report linearly polarized high average power passive Q-switched ytterbium-doped photonic crystal fibre laser with a Cr4+:YAG crystal as a saturable absorber. An average output power of 9.4 W with pulse duration of 64 ns and pulse repetition rate of 57.4 kHz with a slope efficiency of 52% was achieved. Measured polarization extinction ratio (PER) of the Q-switched laser output was 10.5 dB.

  2. Dual Wavelength High Power Double-Clad Ytterbium-Doped Fiber Laser

    Science.gov (United States)

    Moghaddam, M. R. A.; Harun, S. W.; Shahi, S.; Ahmad, H.

    A dual wavelength high power double-clad erbium/ytterbium-doped fiber laser with a narrowest spacing of 0.4 nm and a M2 value of close to unity is presented in the region of 1565 nm. This result can be realized with a significant improvement of the mode competition problem using a loop mirror as a comb filter. The wavelength region can also be varied using polarization controllers in the loop mirror. This dual-wavelength fiber laser with side mode suppression ratio (SMSR) of 40 dB is quite stable, and the output power variance is as low as 0.46 dB.

  3. Passive harmonic mode locked all-normal-dispersion Yb-doped fibre lasers

    Institute of Scientific and Technical Information of China (English)

    Kong Ling-Jie; Xiao Xiao-Sheng; Yang Chang-Xi

    2011-01-01

    Passive harmonic mode-locking of dissipative solitons is demonstrated in all-normal dispersion Yb-doped fibre lasers. A difference equation model of the mode-locked fibre lasers is adopted to simulate the intra-cavity nonlinear dynamics. Hysteresis phenomena around the mode-locking threshold, and the effect of introducing linear phase bias are discussed. The passive harmonic mode-locking as one kind of multipulsing operations is revealed. Moreover, the simulation shows the bistability between multipulsing and single-pulse or period multiplication.

  4. Emitter formation using laser doping technique on n- and p-type c-Si substrates

    Science.gov (United States)

    López, G.; Ortega, P.; Colina, M.; Voz, C.; Martín, I.; Morales-Vilches, A.; Orpella, A.; Alcubilla, R.

    2015-05-01

    In this work laser doping technique is used to create highly-doped regions defined in a point-like structure to form n+/p and p+/n junctions applying a pulsed Nd-YAG 1064 nm laser in the nanosecond regime. In particular, phosphorous-doped silicon carbide stacks (a-SiCx/a-Si:H (n-type)) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) and aluminum oxide (Al2O3) layers deposited by atomic layer deposition (ALD) on 2 ± 0.5 Ω cm p- and n-type FZ c-Si substrates respectively are used as dopant sources. Laser power and number of pulses per spot are explored to obtain the optimal electrical behavior of the formed junctions. To assess the quality of the p+ and n+ regions, the junctions are electrically contacted and characterized by means of dark J-V measurements. Additionally, a diluted HF treatment previous to front metallization has been explored in order to know its impact on the junction quality. The results show that fine tuning of the energy pulse is critical while the number of pulses has minor effect. In general the different HF treatments have no impact in the diode electrical behavior except for an increase of the leakage current in n+/p junctions. The high electrical quality of the junctions makes laser doping, using dielectric layers as dopant source, suitable for solar cell applications. Particularly, a potential open circuit voltage of 0.64 V (1 sun) is expected for a finished solar cell.

  5. Power scaling of a picosecond vortex laser based on a stressed Yb-doped fiber amplifier.

    Science.gov (United States)

    Koyama, Mio; Hirose, Tetsuya; Okida, Masahito; Miyamoto, Katsuhiko; Omatsu, Takashige

    2011-01-17

    Power scaling of a picosecond vortex laser based on a stressed Yb-doped fiber amplifier is analyzed. An output power of 25 W was obtained for 53 W of pumping, with a peak power of 37 kW. Frequency doubling of the vortex output was demonstrated using a nonlinear PPSLT crystal. A second-harmonic output power of up to 1.5 W was measured at a fundamental power of 11.2 W.

  6. On the growth of gadolinia-doped ceria by pulsed laser deposition

    DEFF Research Database (Denmark)

    Pryds, Nini; Rodrigo, Katarzyna Agnieszka; Linderoth, Søren

    2009-01-01

    gadolinia doped ceria (GDC), an electrolytematerial, likely to replace the traditional yttria-stabilised zirconia (YSZ) for low temperature applications. GDC films were grown on a single crystal Si by pulsed laser deposition (PLD). The microstructure of the films as a function of growth time has been...... studied. We have found that the mean grain size increases with film thickness h as h2/5, in agreement with theoretical results....

  7. Different polarization dynamic states in a vector Yb-doped fiber laser.

    Science.gov (United States)

    Li, Xingliang; Zhang, Shumin; Han, Huiyun; Han, Mengmeng; Zhang, Huaxing; Zhao, Luming; Wen, Fang; Yang, Zhenjun

    2015-04-20

    Different polarization dynamic states in an unidirectional, vector, Yb-doped fiber ring laser have been observed. A rich variety of dynamic states, including group velocity locked polarization domains and their splitting into regularly distributed multiple domains, polarization locked square pulses and their harmonic mode locking counterparts, and dissipative soliton resonances have all been observed with different operating parameters. We have also shown experimentally details of the conditions under which polarization-domain-wall dark pulses and bright square pulses form.

  8. Tunable multiwavelength erbium-doped fiber laser based on an in-line Mach Zehnder interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Han, Young-Geun [Hanyang University, Seoul (Korea, Republic of)

    2010-12-15

    A tunable multiwavelength erbium-doped fiber laser based on an in-line Mach Zehnder interferometer is proposed and experimentally demonstrated. The in-line Mach Zehnder interferometer is realized by using cascaded long-period fiber gratings. The long-period fiber gratings can couple the guided core mode to several cladding modes. If two identical long-period fiber gratings are concatenated, an interference pattern can be generated, which results from an interaction of the core and the cladding modes in the second long-period fiber grating. Therefore, a simple multichannel filter based on an in-line Mach Zehnder interferometer can be realized. The wavelength spacing of the proposed multichannel filter is controlled by the number of long-period fiber gratings. We apply the proposed multichannel fiber to the generation of a multiwavelength erbium-doped fiber laser with a tunability on the order of the wavelength spacing. An erbium-doped fiber amplifier is implemented as a gain medium. The gain competition of erbium ions is suppressed by soaking the erbium-doped fiber in liquid nitrogen. The power fluctuation of the proposed multiwavelength fiber laser is measured to be less than 0.5 dB. A high-quality multiwavelength output with a high extinction ratio of more than 40 dB is achieved. The wavelength spacing of the proposed multiwavelength fiber laser is controlled by increasing the number of long-period fiber gratings. The wavelength spacing is changed from 0.8 nm to 1.6 nm discretely.

  9. High power wavelength-defined all-fiber Yb3+-doped double clad fiber laser

    Institute of Scientific and Technical Information of China (English)

    Hongxin Su(苏红新); Kecheng Lü(吕可诚); Peiguang Yan(闫培光); Yigang Li(李乙钢); Xiaoyi Dong(董孝义)

    2003-01-01

    An all-fiber Yb3+-doped double-clad fiber laser using FBGs as cavity mirrors is investigated in this paper.Continuous-wave (CW) output power of 1.18 W with defined wavelength at 1.06 μm and narrow line-widthof less than 0.1 nm is obtained. The slope efficiency and the maximum optical-to-optical efficiency of laseroutput are 68% and 51%, respectively, with respect to absorbed pump power.

  10. High-power Yb- and Tm-doped double tungstate channel waveguide lasers

    NARCIS (Netherlands)

    Dalfsen, van K.; Geskus, D.; Ay, F.; Wörhoff, K.; Aravazhi, S.; Pollnau, M.

    2011-01-01

    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

  11. All-fiber broad-range self-sweeping Yb-doped fiber laser

    Science.gov (United States)

    Lobach, Ivan A.; Kablukov, Sergey A.; Podivilov, Evgeniy V.; Babin, Sergey A.

    2012-02-01

    The effect of broad-range self-sweeping in Yb-doped fiber laser has been demonstrated experimentally for the first time. The self-sweeping effect is observed in an all-fiber laser configuration with a double-clad Yb-doped fiber and a cavity formed by a broad-band fiber loop mirror and Fresnel reflection from one cleaved end. The sweep range is limited by the width of the broad-band reflector and reaches up to 16nm. It is found that the self-sweeping effect is related to selfpulsations. So the sweep rate is increased with an increase in pump power and is decreased with increasing cavity length. RF and optical spectra (linewidth is measured to be not more than 100 MHz) show that during the evolution of a single pulse a small number of longitudinal modes take a part in lasing. Based on these results we propose a model describing dynamics of the laser frequency. The model is based on the spatial hole burning effect and the gain saturation in Yb laser transition, and takes into account self-pulsations of the laser. Theoretical estimation for pulse to pulse change of lasing frequency is in good agreement with experimental data.

  12. Multiwavelength narrow linewidth erbium-doped fiber laser based on FP-LDs.

    Science.gov (United States)

    Zhang, Aiqin; Jin, Yanbing; Feng, Xinhuan; Zhou, Jingjuan; Li, Zhaohui; Guan, Bai-Ou

    2013-07-15

    In this paper, we propose and demonstrate a technique to realize multiwavelength operation in erbium-doped fiber lasers (EDFLs) by inserting two Fabry Pérot laser diodes (FP-LDs) in the laser cavity respectively in cascaded and parallel way. The FP-LDs not only act as wavelength selection elements, but also offer optical gain or loss for the operation wavelengths in the laser cavity. The gains or losses for the oscillation wavelengths obtained from FP-LDs differ with adjustment of the driving current of the FP-LDs. Thus, the utilization of the FP-LDs in the laser cavity can introduce wavelength dependent gain or loss which can effectively suppress the competition caused by the homogeneous gain broadening of the erbium-doped fiber (EDF). As a result, 16-wavelength and 20-wavelength operation with a wavelength-spacing of 1.25 nm has been achieved respectively in the cascaded and parallel FP-LDs based EDFL schemes. The measured power fluctuation of each wavelength is smaller than 0.4dB for both EDFLs. Furthermore, the injection locking of the FP-LDs ensures a narrow linewidth of the EDFL output and the linewidth is estimated to be narrower than 100 MHz for the cascaded scheme based EDFL.

  13. Gamma-ray-induced damage and recovery behavior in an erbium-doped fiber laser

    Science.gov (United States)

    Bussjager, Rebecca J.; Hayduk, Michael J.; Johns, Steven T.; Taylor, Linda R.; Taylor, Edward W.

    2002-01-01

    Erbium-doped fiber lasers (EDFLs) may soon find applications in space as high bit rate optical communication systems and photonic analog-to-digital converters (ADCs). The rapid advancement in digital signal processing systems has led to an increased interest in the direct digitization of high- frequency analog signals. The potential high bandwidth, reduced weight, and reduced power requirements makes photonics an attractive technology for wide-band signal conversion as well as for use in space-based platforms. It is anticipated that photonic ADCs will be able to operate at sampling rates and resolutions far greater than current electronic ADCs. The high repetition rates and narrow pulse widths produced by EDFLs allow for high-speed impulse sampling of analog signals thus making it a vital component of a photonic ADC. In this paper we report on the in situ gamma-ray irradiation of an actively mode-locked EDFL operating at 1530 nm. The onset, growth and extent of ionization induced damage under time-resolved operational conditions is presented. The laser consisted of approximately 3 meters of erbium-doped fiber pumped by a laser diode operating at 980 nm. The picosecond pulses produced by the laser were initiated and controlled by a Mach-Zehnder lithium niobate electro-optic modulator. The active mode-locking element allowed for the precise timing control of the laser repetition rate which is critical in high-speed optical networking systems as well as in photonic ADCs.

  14. Study of the amplified spontaneous emission in a dye-doped biopolymer-based material

    Energy Technology Data Exchange (ETDEWEB)

    Mysliwiec, J; Sznitko, L; Miniewicz, A [Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology, Wyb.Wyspianskiego 27, 50-370 Wroclaw (Poland); Kajzar, F; Sahraoui, B, E-mail: jaroslaw.mysliwiec@pwr.wroc.p [Laboratoire POMA CNRS FRE 2988, Universite d' Angers, 2 Bd Lavoisier, 49 045 Angers (France)

    2009-04-21

    In this paper we investigate the amplified spontaneous emission (ASE) phenomenon in the system based on a dye dissolved in a modified deoxyribonucleic acid (DNA). The system consisted of a biopolymeric matrix made of DNA blended with cationic surfactant molecule cetyltrimethyl-ammonium chloride (CTMA) and doped with a well-known rhodamine (Rh 6G) laser dye. Thin films of the DNA-CTMA : Rh6G were excited at {lambda} = 532 nm wavelength with 8 ns laser pulses. We report on ASE intensity as a function of the laser power, dependence of polarization state of the excitation beam, ASE gain and temporal stability of the signal for the investigated system.

  15. Transient Infrared Measurement of Laser Absorption Properties of Porous Materials

    Directory of Open Access Journals (Sweden)

    Marynowicz Andrzej

    2016-06-01

    Full Text Available The infrared thermography measurements of porous building materials have become more frequent in recent years. Many accompanying techniques for the thermal field generation have been developed, including one based on laser radiation. This work presents a simple optimization technique for estimation of the laser beam absorption for selected porous building materials, namely clinker brick and cement mortar. The transient temperature measurements were performed with the use of infrared camera during laser-induced heating-up of the samples’ surfaces. As the results, the absorbed fractions of the incident laser beam together with its shape parameter are reported.

  16. Transient Infrared Measurement of Laser Absorption Properties of Porous Materials

    Science.gov (United States)

    Marynowicz, Andrzej

    2016-06-01

    The infrared thermography measurements of porous building materials have become more frequent in recent years. Many accompanying techniques for the thermal field generation have been developed, including one based on laser radiation. This work presents a simple optimization technique for estimation of the laser beam absorption for selected porous building materials, namely clinker brick and cement mortar. The transient temperature measurements were performed with the use of infrared camera during laser-induced heating-up of the samples' surfaces. As the results, the absorbed fractions of the incident laser beam together with its shape parameter are reported.

  17. Material Processing Laser Systems For Manufacturing

    Science.gov (United States)

    Taeusch, David R.; Ruselowski, John M.

    1986-11-01

    Raycon Corporation is a builder of quality machine tools. Combining this with applications expertise to produce high technology production machinery systems using EDM, lasers and other processing methods to solve our customers' production problems is our product. The company has several standard laser machine systems which can be constructed from standard building blocks. The number of axes and travel, the controller requirements, and the required laser type, size and manufacturer are discussed with our customers, and the system to meet their needs is decided upon. These requirements are then built into a processing system for manufacturing use. Several of these systems which are in the field are described, and their purposes and how they accomplish their task are explained. Also, types of YAG and C02 lasers available are described and their optimum use explained. Some specific examples of type versus applications are: YAG low-divergence lasers for trepanning heat-resistant alloys for jet engine turbines; YAG oscillator-amplifier lasers for percussion drilling of cooling holes in jet engine turbine blades; and several special laser machine systems for processing automotive parts are discussed. A few words on laser safety are included to allay some common fears concerning the use of laser technology in the factory environment.

  18. Effect of Moisture Content of Paper Material on Laser Cutting

    Science.gov (United States)

    Stepanov, Alexander; Saukkonen, Esa; Piili, Heidi; Salminen, Antti

    Laser technology has been used in industrial processes for several decades. The most advanced development and implementation took place in laser welding and cutting of metals in automotive and ship building industries. However, there is high potential to apply laser processing to other materials in various industrial fields. One of these potential fields could be paper industry to fulfill the demand for high quality, fast and reliable cutting technology. Difficulties in industrial application of laser cutting for paper industry are associated to lack of basic information, awareness of technology and its application possibilities. Nowadays possibilities of using laser cutting for paper materials are widened and high automation level of equipment has made this technology more interesting for manufacturing processes. Promising area of laser cutting application at paper making machines is longitudinal cutting of paper web (edge trimming). There are few locations at a paper making machine where edge trimming is usually done: wet press section, calender or rewinder. Paper web is characterized with different moisture content at different points of the paper making machine. The objective of this study was to investigate the effect of moisture content of paper material on laser cutting parameters. Effect of moisture content on cellulose fibers, laser absorption and energy needed for cutting is described as well. Laser cutting tests were carried out using CO2 laser.

  19. High Power Lasers And Their Application In Materials Processing

    Science.gov (United States)

    Bohn, W. L.

    1985-02-01

    The idea of using a laser for materials processing is more than 20 years old. Although the concept of a non-contact method for processing with a beam of light has been pursued with great interest and enthusiasm, the practical use of laser beam processing was slow to develop. The lasers available in the 1960's were fragile and of relatively low power. In the 1970's lasers in the multi-kilowatt range were developed but the problem of laser acceptance by the customer had to be overcome. Today, reliable Nd-Yag and CO2-lasers are available and laser processing is a fast growing market. An additional boost is expected with the development of the next generation of lasers and with increased knowledge of the physical phenomena that underlie laser material processing. This paper will review latest developments in laser technology and laser-workpiece interaction with special emphasis on the impact of high speed photography on the research work in these areas.

  20. The influence of Fe doping on the surface topography of GaN epitaxial material

    Science.gov (United States)

    Lei, Cui; Haibo, Yin; Lijuan, Jiang; Quan, Wang; Chun, Feng; Hongling, Xiao; Cuimei, Wang; Jiamin, Gong; Bo, Zhang; Baiquan, Li; Xiaoliang, Wang; Zhanguo, Wang

    2015-10-01

    Fe doping is an effective method to obtain high resistivity GaN epitaxial material. But in some cases, Fe doping could result in serious deterioration of the GaN material surface topography, which will affect the electrical properties of two dimensional electron gas (2DEG) in HEMT device. In this paper, the influence of Fe doping on the surface topography of GaN epitaxial material is studied. The results of experiments indicate that the surface topography of Fe-doped GaN epitaxial material can be effectively improved and the resistivity could be increased after increasing the growth rate of GaN materials. The GaN material with good surface topography can be manufactured when the Fe doping concentration is 9 × 1019 cm-3. High resistivity GaN epitaxial material which is 1 × 109 Ω·cm is achieved. Project supported by the Knowledge Innovation Engineering of the Chinese Academy of Sciences (No. YYY-0701-02), the National Natural Science Foundation of China (Nos. 61204017, 61334002), the State Key Development Program for Basic Research of China, and the National Science and Technology Major Project.

  1. Lead Telluride Doped with Au as a Very Promising Material for Thermoelectric Applications

    Directory of Open Access Journals (Sweden)

    Pantelija M. Nikolic

    2015-01-01

    Full Text Available PbTe single crystals doped with monovalent Au or Cu were grown using the Bridgman method. Far infrared reflectivity spectra were measured at room temperature for all samples and plasma minima were registered. These experimental spectra were numerically analyzed and optical parameters were calculated. All the samples of PbTe doped with Au or Cu were of the “n” type. The properties of these compositions were analyzed and compared with PbTe containing other dopants. The samples of PbTe doped with only 3.3 at% Au were the best among the PbTe + Au samples having the lowest plasma frequency and the highest mobility of free carriers-electrons, while PbTe doped with Cu was the opposite. Samples with the lowest Cu concentration of 0.23 at% Cu had the best properties. Thermal diffusivity and electronic transport properties of the same PbTe doped samples were also investigated using a photoacoustic (PA method with the transmission detection configuration. The results obtained with the far infrared and photoacoustic characterization of PbTe doped samples were compared and discussed. Both methods confirmed that when PbTe was doped with 3.3 at% Au, thermoelectric and electrical properties of this doped semiconductor were both significantly improved, so Au as a dopant in PbTe could be used as a new high quality thermoelectric material.

  2. Terahertz generation and detection using femtosecond mode-locked Yb-doped fiber laser

    Science.gov (United States)

    Kong, Moon Sik; Kim, Ji Su; Han, Sang-Pil; Kim, Namje; Moon, Ki Won; Park, Kyung Hyun; Jeon, Min Yong

    2016-02-01

    We successfully demonstrate a THz generation using an ytterbium (Yb)-doped mode-locked femtosecond fiber laser and a home-made low-temperature grown (LTG) InGaAs Photoconductive antenna (PCA) module for THz Time-domain spectroscopy (TDS) systems. The Yb-doped fiber ring laser consists of a pump laser diode (PLD), a wavelength division multiplexer (WDM) coupler, a single-mode fiber (SMF), a 25 cm-long highly Yb-doped fiber, two collimators, two quarter wave plates (QWPs), a half-wave plate (HWP), a 10 nm broadband band pass filter, an isolator, and a polarizing beam splitter (PBS). In order to achieve the passively mode-locked optical short pulse, the nonlinear polarization rotation (NPR) effect is used. The achieved center wavelength and the 3 dB bandwidth of the modelocked fiber laser are 1.03 μm and ~ 15.6 nm, respectively. It has 175 fs duration after pulse compression with 66.2 MHz repetition rate. The average output power of mode-locked laser has more than 275 mW. The LTG-InGaAs PCA modules are used as the emitter and receiver in order to achieve the THz radiation. The PCA modules comprise a hyper-hemispherical Si lens and a log-spiral antenna-integrated LTG-InGaAs PCA chip electronically contacted on a printed circuit board (PCB). An excitation optical average pumping and probing power were ~ 6.3 mW and 5 mW, respectively. The free-space distance between the emitter and the receiver in the THz-TDS system was 70 mm. The spectrum of the THz radiation is achieved higher than 1.5 THz.

  3. Laser processing for manufacturing nanocarbon materials

    Science.gov (United States)

    Van, Hai Hoang

    CNTs have been considered as the excellent candidate to revolutionize a broad range of applications. There have been many method developed to manipulate the chemistry and the structure of CNTs. Laser with non-contact treatment capability exhibits many processing advantages, including solid-state treatment, extremely fast processing rate, and high processing resolution. In addition, the outstanding monochromatic, coherent, and directional beam generates the powerful energy absorption and the resultant extreme processing conditions. In my research, a unique laser scanning method was developed to process CNTs, controlling the oxidation and the graphitization. The achieved controllability of this method was applied to address the important issues of the current CNT processing methods for three applications. The controllable oxidation of CNTs by laser scanning method was applied to cut CNT films to produce high-performance cathodes for FE devices. The production method includes two important self-developed techniques to produce the cold cathodes: the production of highly oriented and uniformly distributed CNT sheets and the precise laser trimming process. Laser cutting is the unique method to produce the cathodes with remarkable features, including ultrathin freestanding structure (~200 nm), greatly high aspect ratio, hybrid CNT-GNR emitter arrays, even emitter separation, and directional emitter alignment. This unique cathode structure was unachievable by other methods. The developed FE devices successfully solved the screening effect issue encounter by current FE devices. The laser-control oxidation method was further developed to sequentially remove graphitic walls of CNTs. The laser oxidation process was directed to occur along the CNT axes by the laser scanning direction. Additionally, the oxidation was further assisted by the curvature stress and the thermal expansion of the graphitic nanotubes, ultimately opening (namely unzipping) the tubular structure to

  4. Planar waveguide amplifiers and laser in erbium doped silica

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas; Kristensen, Martin

    1999-01-01

    The objective of this work was to develop optically amplifying planar waveguides, using erbium-doped germano-silicate glass films deposited by PECVD (Plasma Enhanced Chemical Vapour Deposition). The waveguides should exhibit enough gain to be useful as optical amplifiers in integrated planar...... fluorescence level. In addition the first measurement of the diffusion coefficient of erbim in silica is presented and it is shown that erbium rich precipitates are formed in areas of high erbium concentration. The manufacturing of planar waveguide structures using RIE (Reactive Ion Etching) is described...... and it is shown that sidewall roughness resulting from micro masking by non-volatile reaction products can be minimised through a careful choice of etching parameters. This results in low propagation loss for the fabricated waveguides. It is shown that the achievable population inversion depends on the eribum...

  5. Laser Cutting of Materials of Various Thicknesses

    Directory of Open Access Journals (Sweden)

    Martin Grepl

    2012-01-01

    Full Text Available Thise paper deals with the application of laser technology and optimizing the parameters for cutting nickel alloy. The theoretical part of the paper describes various types of lasers, their principles and usage. The experimental part focuses on optimizing the section parameteres of Haynes 718 alloy using a CO2 gas laser. This alloy is employed in the production of components for the aircraft industry. The experiment was performed on the Wibro Delta laser system designed for sizable parts. The actual section is measured with respect to its quality and any accompanying side effects that occur during the process. In this case, laser output and cutting speed were the parameters with most influence on the final cut. The summary explains the results achieved in a metallographic laboratory.

  6. Rare-Earth Doped Photonic Crystal Fibre Lasers and Amplifiers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.

    2005-01-01

    In this thesis, a theoretical and numerical study of the use of rare-earthdoped photonic crystal fibres as optical amplifiers and lasers, has been performed. Photonic crystal fibres or microstructured optical fibres is a new kind of optical fibre in which the cladding region typically consist...... of a periodic microstructure, resulting in a fibre with very different properties compared to conventional optical fibres. The properties of photonic crystals fibres are described, with focus on the advantages this technology provides compared to conventional fibres, within the area of optical amplification....... The thesis also presents the basic properties of optical amplification, and describes the numerical model developed to model the behaviour of lasers and amplifiers based on photonic crystal fibres. The developed numerical tools are then used to investigate specific applications of photonic crystal fibres...

  7. Nitrogen-Doped Carbon Nanotube and Graphene Materials for Oxygen Reduction Reactions

    Directory of Open Access Journals (Sweden)

    Qiliang Wei

    2015-09-01

    Full Text Available Nitrogen-doped carbon materials, including nitrogen-doped carbon nanotubes (NCNTs and nitrogen-doped graphene (NG, have attracted increasing attention for oxygen reduction reaction (ORR in metal-air batteries and fuel cell applications, due to their optimal properties including excellent electronic conductivity, 4e− transfer and superb mechanical properties. Here, the recent progress of NCNTs- and NG-based catalysts for ORR is reviewed. Firstly, the general preparation routes of these two N-doped carbon-allotropes are introduced briefly, and then a special emphasis is placed on the developments of both NCNTs and NG as promising metal-free catalysts and/or catalyst support materials for ORR. All these efficient ORR electrocatalysts feature a low cost, high durability and excellent performance, and are thus the key factors in accelerating the widespread commercialization of metal-air battery and fuel cell technologies.

  8. Iron-Doped Zinc Selenide: Spectroscopy and Laser Development

    Science.gov (United States)

    2014-03-27

    3 PRF pulse repetition frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 DPSS diode ...4800 300 2006 Akimov [24] SC ZnSe GS 370 µJ 3950–5050 300 2006 Gallian [25] PC ZnSe GS — 4450 300 2008 Il’ichev [26] PC ZnSe Superluminescence ∼ 1 mJ... diode -pumped solid-state (DPSS) Er:YAG laser modules emitting at 2937 nm with 1.5 W of CW output power are now available [32]. Using beam combination

  9. Towards manipulating relativistic laser pulses with 3D printed materials

    CERN Document Server

    Ji, L L; Pukhov, A; Freeman, R R; Akli, K U

    2015-01-01

    Efficient coupling of intense laser pulses to solid-density matter is critical to many applications including ion acceleration for cancer therapy. At relativistic intensities, the focus has been mainly on investigating various laser beams irradiating initially flat interfaces with little or no control over the interaction. Here, we propose a novel approach that leverages recent advancements in 3D direct laser writing (DLW) of materials and high contrast lasers to manipulate the laser-matter interactions on the micro-scales. We demonstrate, via simulations, that usable intensities >10^23Wcm^(-2) could be achieved with current tabletop lasers coupled to 3D printed plasma lenses. We show that these plasma optical elements act not only as a lens to focus laser light, but also as an electromagnetic guide for secondary particle beams. These results open new paths to engineering light-matter interactions at ultra-relativistic intensities.

  10. Improvements in laser flare removal for particle image velocimetry using fluorescent dye-doped particles

    Science.gov (United States)

    Petrosky, B. J.; Lowe, K. T.; Danehy, P. M.; Wohl, C. J.; Tiemsin, P. I.

    2015-11-01

    Laser flare, or scattering of laser light from a surface, can often be a major issue in particle image velocimetry (PIV) involving solid boundaries in the flow or a gas-liquid interface. The use of fluorescent light from dye-doped particles has been demonstrated in water applications, but reproducing the technique in an airflow is more difficult due to particle size constraints and safety concerns. The following work presents fluorescent Kiton Red 620 (KR620)-doped polystyrene latex microspheres as a solution to this issue. The particles are small and narrowly distributed, with a mean diameter of 0.87 μ \\text{m} and diameter distribution standard deviation of 0.30 μ \\text{m} . Furthermore, the KR620 dye exhibits much lower toxicity than other common fluorescent dyes, and would be safe to use in large flow facilities. The fluorescent signal from the particles is measured on average to be 320  ±  10 times weaker than the Mie scattering signal from the particles. This reduction in signal is counterbalanced by greatly enhanced contrast via optical rejection of the incident laser wavelength. Fluorescent PIV with these particles is shown to eliminate laser flare near surfaces, allowing for velocity measurements as close as 100 μ \\text{m} to the surface. In one case, fluorescent PIV led to velocity vector validation rates more than 20 times that of the Mie scattering results in the boundary layer region of an angled surface.

  11. High-sensitivity sucrose erbium-doped fiber ring laser sensor

    Science.gov (United States)

    Khaleel, Wurood Abdulkhaleq; Al-Janabi, Abdul Hadi M.

    2017-02-01

    We investigate a high-sensitivity sucrose sensor based on a standard erbium-doped fiber ring laser incorporating a coreless fiber (CF). A single-mode-coreless-single mode (SCS) structure with a very low insertion loss has been constructed. The SCS fiber structure performed dual function as an intracavity fiber filter and/or a sensing element. The gain medium (erbium-doped fiber) is pumped by a 975-nm wavelength fiber coupled diode laser. Laser emission around 1537 nm with -2 dBm peak output power is obtained when a CF in SCS structure has a diameter of 125 μm. The 3-dB line-width of the laser is <0.14 nm, which is beneficial to high precision sensing. The sucrose concentration varied from 0% to 60%, and the relationship between the lasing wavelength and the sucrose concentration exhibited linear behavior (R2=0.996), with sensitivity of 0.16 nm/% was obtained. To improve the measurement sensitivity, the CF is etched by hydrofluoric acid. The splice joint of etched CF with SMF is a taper, which improves its sensitivity to sucrose changes. An average sensitivity of 0.57 nm/% and a high signal-to-noise ratio of 50 dB make the proposed sensor suitable for potential applications.

  12. A femtosecond Yb-doped fiber laser with generalized vector vortex beams output (Conference Presentation)

    Science.gov (United States)

    Huo, Tiancheng; Qi, Li; Zhang, Buyun; Chen, Zhongping

    2017-03-01

    Light carries both spin and orbital angular momentum (OAM) and the superpositions of these two dynamical properties have found many applications. Many techniques exist to create such light sources but none allow their creation at the femtosecond fiber laser. Here we report on a novel mode-locked Ytterbium-doped fiber laser that generates femtosecond pulses with generalized vector vortex states. The controlled generation of such pulses such as azimuthally and radially polarized light with definite orbital angular momentum modes are demonstrated. A unidirectional ring cavity constructed with the Yb-doped fiber placed at the end of the fiber section to reduces unnecessary nonlinear effects is employed for self-starting operation. Pairs of diffraction gratings are used for compensating the normal group velocity dispersion of the fiber and other elements. Mode-locked operation is achieved based on nonlinear polarization evolution, which is mainly implemented with the single mode fiber, the bulk wave plates and the variable spiral plates (q-plate with topological charge q=0.5). The conversion from spin angular momentum to the OAM and reverse inside the laser cavity are realized by means of a quarter-wave plate and a q-plate so that the polarization control was mapped to OAM mode control. The fiber laser is diode pumped by a wavelength-division multiplexing coupler, which leads to excellent stability and portability.

  13. Influence of Zn Doping on Novel Cathode Material LiFePO4

    Institute of Scientific and Technical Information of China (English)

    H. Liu; C. Li; Q. Cao; H.P. Zhang; Y.P. Wu; H.Q. Wu

    2005-01-01

    @@ 1Introduction The novel cathode material LiFePO4 for lithium ion battery is considered as the substitute of LiCoO2 because of its high theoretical capacity, environmental benignancy and inexpensive cost[1,2]. But it is restricted by its low conductivity, the traditional ways to improve are carbon coating[3,4] and heteroatom doping[5-7].In this paper, we introduced the Zn as heteroatom and investigated the improvement by Zn doping.

  14. Laser -Based Joining of Metallic and Non-metallic Materials

    Science.gov (United States)

    Padmanabham, G.; Shanmugarajan, B.

    Laser as a high intensity heat source can be effectively used for joining of materials by fusion welding and brazing in autogenous or in hybrid modes. In autogenous mode, welding is done in conduction , deep penetration , and keyhole mode. However, due to inherently high energy density available from a laser source, autogenous keyhole welding is the most popular laser welding mode. But, it has certain limitations like need for extremely good joint fit-up, formation of very hard welds in steel , keyhole instability, loss of alloying elements, etc. To overcome these limitations, innovative variants such as laser-arc hybrid welding , induction-assisted welding , dual beam welding , etc., have been developed. Using laser heat, brazing can be performed by melting a filler to fill the joints, without melting the base materials. Accomplishing laser-based joining as mentioned above requires appropriate choice of laser source, beam delivery system, processing head with appropriate optics and accessories. Basic principles of various laser-based joining processes, laser system technology, process parameters, metallurgical effects on different base materials, joint performance, and applications are explained in this chapter.

  15. Ultrafast Laser Dynamics and Interactions in Complex Materials

    Science.gov (United States)

    Patz, Aaron Edward

    The work described in this thesis underscores specific examples of using an ultrafast laser as a materials research tool for studying condensed matter physics in complex materials. The majority of materials studied fall into the iron-pnictide class of unconventional superconductors, which exhibit a multitude of phases that appear to be dependent on each other, or the magnetic semiconductor, GaMnAs. In my work I show various ultrafast laser techniques for studying these complex materials in order to decouple the different properties in the time-domain and gain information about the underlying physics governing the material properties.

  16. Functionally graded materials produced with high power lasers

    NARCIS (Netherlands)

    De Hosson, JTM; Ocelík, Vašek; Chandra, T; Torralba, JM; Sakai, T

    2003-01-01

    In this keynote paper two examples will be present of functionally graded materials produced with high power Nd:YAG lasers. In particular the conditions for a successful Laser Melt Injection (LMI) of SiC and WC particles into the melt pool of A18Si and Ti6Al4V alloys are presented. The formation of

  17. Lanthanide doped ceria thin films as possible counter electrode materials in electrochromic devices

    CERN Document Server

    Hartridge, A

    2000-01-01

    suitability of these thin films as counter electrodes in electrochromic devices. The final chapter then turns to the electrochemical insertion of lithium into these materials using cyclic voltammetry. All films studied enabled the reversible insertion of lithium with varying potentials and charge capacities without the loss of transmission of light common to other potential counter electrode materials. Certain compositions however, comprising ceria doped with Dy, Y, Nd and Pr, allowed enough lithium insertion (charge capacity) to fulfil the requirements of counter electrode materials in electrochromic devices. These materials are therefore worthy of further study. Crystalline solid solutions of lanthanide doped ceria have long been known for their high ionic conductivity and as such have found applications as oxygen sensors and in solid oxide fuel cells. With advances in preparative techniques over the years, thin films of ceria doped with zirconia and titania have been studied and found to possess the necess...

  18. Pulsed laser deposition and thermoelectric properties of In-and Yb-doped CoSb3 skutterudite thin films

    KAUST Repository

    Sarath Kumar, S. R.

    2011-07-29

    In-and Yb-doped CoSb3 thin films were prepared by pulsed laser deposition. Process optimization studies revealed that a very narrow process window exists for the growth of single-phase skutterudite films. The electrical conductivity and Seebeck coefficient measured in the temperature range 300-700 K revealed an irreversible change on the first heating cycle in argon ambient, which is attributed to the enhanced surface roughness of the films or trace secondary phases. A power factor of 0.68 W m-1 K-1 was obtained at ∼700 K, which is nearly six times lower than that of bulk samples. This difference is attributed to grain boundary scattering that causes a drop in film conductivity. Copyright © Materials Research Society 2011.

  19. Glassy behavior in a one-dimensional continuous-wave erbium-doped random fiber laser

    Science.gov (United States)

    Gomes, Anderson S. L.; Lima, Bismarck C.; Pincheira, Pablo I. R.; Moura, André L.; Gagné, Mathieu; Raposo, Ernesto P.; de Araújo, Cid B.; Kashyap, Raman

    2016-07-01

    The photonic analog of the paramagnetic to spin-glass phase transition in disordered magnetic systems, signaled by the phenomenon of replica symmetry breaking, has been reported using random lasers as the photonic platform. We report here a demonstration of replica symmetry breaking in a one-dimensional photonic system consisting of an erbium-doped random fiber laser operating in the continuous-wave regime. The system is based on a unique random fiber grating system which plays the role of random scattering, providing the disordered feedback mechanism. The clear transition from a photonic paramagnetic to a photonic spin-glass phase, characterized by the Parisi overlap parameter, was verified and indicates the glassy random-fiber-laser behavior.

  20. Stable and high-performance multiwavelength erbium-doped fiber laser based on fiber delay interferometer

    Institute of Scientific and Technical Information of China (English)

    Shuang LIU; Junqiang SUN; Ping SHUM

    2009-01-01

    In this paper, we proposed a novel scheme to realize the multiwavelength erbium-doped fiber lasers. By adding a length of dispersion shifted fiber (DSF) in the ring cavity, we can suppress the cavity mode competition resulting from homogeneous line broadening (HLB) effect. In addition, a comb filter based on fiber delay inter-ferometer (DI) is used for frequency selecting. To enhance the extinction ratio while maintaining the free space range (FSR), the proposed isolator-assisted double-pass DI is utilized into the laser cavity, and a stable 7-wavelength simultaneous lasing spaced at 21.5GHz is accordingly achieved with an extinction ratio of higher than 40 dB. The lasers are stable with a maximum power fluctuation per channel of less than 0.6 dB during an hour test.

  1. Single- and dual-wavelength switchable linear polarized Yb(3+)-doped double-clad fiber laser.

    Science.gov (United States)

    Liu, Guanxiu; Feng, Dejun

    2015-05-10

    A single- and dual-wavelength switchable linear polarized Yb-doped double-clad fiber laser is proposed, in which the resonance cavity was composed of a fiber Bragg grating fabricated in a polarization-maintaining fiber and a dichromatic mirror with high reflectivity. The polarization hole burning is enhanced through selective polarization feedback by the polarization-maintaining fiber Bragg grating. The switchover of single and dual wavelengths is realized by tuning the rotation angle of a cubic polarization beam splitter that is inserted between the dichromatic mirror and the collimator in the cavity. The laser features wavelengths of 1070.08 and 1070.39 nm, output power of 1.0 W, signal to noise ratio of 45 dB, and slope efficiency of 34%, as well as a very narrow linewidth of 0.022 nm. The polarization characteristics are analyzed by measuring the laser power transmitted through a Glan-Thomson polarizer during rotation.

  2. Multi-coupler side-pumped Yb-doped double-clad fiber laser

    Institute of Scientific and Technical Information of China (English)

    Pan Ou(欧攀); Ping Yan(闫平); Mali Gong(巩马理); Wenlou Wei(韦文楼)

    2004-01-01

    The side-coupler of angle polished method, using angle-polished multimode fiber and optical adhesive, is used to efficiently pump an Yb-doped double-clad fiber laser. The maximum coupling efficiency of 78.6% is achieved by the side-coupler for a multimode fiber with a circular core of 200 μm and a double-clad fiber with a 350/400 μm D-shaped inner cladding. While laser diodes (LDs) with three side-couplers are simultaneously used as pump sources, maximum output power of 1.38 W and slope efficiency of 48.9% are demonstrated in the fiber laser system.

  3. Multi-coupler side-pumped Yb-doped double-clad fiber laser

    Institute of Scientific and Technical Information of China (English)

    欧攀; 闫平; 巩马理; 韦文楼

    2004-01-01

    The side-coupler of angle polished method, using angle-polished multimode fiber and optical adhesive, is used to efficiently pump an Yb-doped double-clad fiber laser. The maximum coupling efficiency of 78.6%is achieved by the side-coupler for a multimode fiber with a circular core of 200 μm and a double-clad fiber with a 350/400 μm D-shaped inner cladding. While laser diodes (LDs) with three side-couplers are simultaneously used as pump sources, maximum output power of 1.38 W and slope efficiency of 48.9% are demonstrated in the fiber laser system.

  4. Laser Induced Modification of the Optical Properties of Nano-ZnO Doped PVC Films

    Directory of Open Access Journals (Sweden)

    Tagreed K. Hamad

    2014-01-01

    Full Text Available The effect of continuous CO2 laser radiation on the optical properties of pure polyvinyl chloride and doped of ZnO nanoparticles with two different concentrations (10, 15% has been investigated. All samples were prepared using casting method at room temperature. Optical properties (absorption, transmission, absorption coefficient, extinction coefficient, refractive index, and optical conductivity of all films after CO2 laser irradiated have been studied as a function of the wavelength in the range (200–800 nm for three energies (300, 400 and 500 mJ. It has been found that the transmission, energy gap, and refractive index increase with increasing laser energy. The values of absorption, Urbach energy, absorption coefficient, extinction coefficient, and optical conductivity were decreased.

  5. Novel rib structures in Yb-doped KY(WO4)2 for laser applications

    NARCIS (Netherlands)

    Gardillou, F.; Borca, C.N.; Romanyuk, Y.E.; Hibert, C.; Salathé, R.P.; Pollnau, Markus

    2006-01-01

    We report for the first time, on the fabrication of flexible refractive-index-contrast rib waveguides based on Yb-doped $KY(WO_4)_2$ epilayers. These results pave the way for integrated optical circuits in this promising material.

  6. Ferromagnetism in Transition Metal Doped GaN and Related Materials

    Science.gov (United States)

    Abernathy, Cammy

    2005-03-01

    There is high current interest in the development of dilute magnetic semiconductor (DMS) materials exhibiting ferromagnetic behavior for spin-based light-emitting diodes, sensors, and transistors. Such materials are formed through the introduction of transition metal (TM) ions, such as Mn and Cr, into semiconductor hosts. Unfortunately many DMS materials, such as GaMnAs, have a relatively low magnetic ordering temperature ( 170 K for GaMnAs), which severely limits their usefulness. In the past few years, several groups have reported achieving ferromagnetism at room temperature in wide bandgap materials, such as GaMnN. This property makes these materials attractive for use as ultra-low-power switching elements, where the bit state of the device is determined through control of electron spin. Furthermore, these materials may also allow for the integration of photonic (laser and light-emitting diodes), electronic (field-effect and bipolar transistors) and magnetic (information storage) devices on a single substrate, leading to a new class of electronic devices that offer multi-purpose functionality. However, to realize such devices, several challenges remain. One concern to date has been the relatively low thermal stability of the III-Mn-N compounds. Doping with Cr in place of Mn, however, appears to greatly enhance the ability of the material to retain its magnetic properties even after annealing at temperatures up to 700C, easing the road to practical device fabrication. In addition, the ability to achieve magnetic behavior in a semi-insulating barrier material such as AlCrN opens new device possibilities. The most evident application of ferromagnetic AlN is as a ferromagnetic tunnel barrier, similar to EuS, but unlike EuS should allow for operation at room temperature. Growth of tunnel devices using Al-TM-N as a barrier and Ga-TM-N as a spin injector will be discussed. This work is supported by the Army Research Office under ARO-DAAD19-01-0-0701 and NSF under ECS

  7. Push-out bond strength of oval versus circular fiber posts irradiated by erbium-doped yttrium aluminum garnet laser.

    Science.gov (United States)

    Uzun, Ismail; Keskin, Cangül; Özsu, Damla; Güler, Buğra; Aydemir, Hikmet

    2016-09-01

    Fiber posts in conjunction with resin cements are widely used to provide retention in endodontically treated teeth. The bond strength of restorative materials to root canal dentin is an important issue for the long-term success of restorative procedures. The push-out test is widely used to measure the bonding between the post and radicular dentin. The purpose of this in vitro study was to evaluate the effect of erbium-doped yttrium aluminum garnet (Er-YAG) laser treatment of dentinal walls on the bond strength of circular and oval fiber posts luted in oval root canals. Forty mandibular premolar teeth were endodontically treated and restored with 2 different intracanal post systems. Push-out tests were performed and data were analyzed by using 2-way analysis of variance and post hoc Bonferroni tests. Laser pretreatment of dentinal walls resulted in higher push-out bond strength than that of the nonlasered groups (Pfiber posts showed significantly higher push-out bond strength values than those of circular fiber posts in the coronal region (P.05). The laser pretreatment with an oval ultrasonic tip of an oval fiber post system improved bonding to root canal dentin when compared with a circular post system with conventional preparation. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  8. Benefit of Rare-Earth "Smart Doping" and Material Nanostructuring for the Next Generation of Er-Doped Fibers

    Science.gov (United States)

    Savelii, Inna; Bigot, Laurent; Capoen, Bruno; Gonnet, Cedric; Chanéac, Corinne; Burova, Ekaterina; Pastouret, Alain; El-Hamzaoui, Hicham; Bouazaoui, Mohamed

    2017-03-01

    Erbium-doped fiber amplifiers (EDFAs) for harsh environments require to develop specific fabrication methods of Er 3+-doped fibers (EDFs) so as to limit the impact of radiation-induced absorption. In this context, a compromise has to be found between the concentration of Erbium and the glass composition. On the one hand, high concentration of Er 3+ ions helps to reduce the length of the EDF and hence the cumulated attenuation but generally leads to luminescence quenching mechanisms that limit the performances. On the other hand, so as to avoid such quenching effect, glass modifiers like Al 3+ or P 5+ ions are used in the fabrication of commercial EDFs but are not suitable for applications in harsh environment because these glass modifiers are precursors of radiation-induced structural defects and consequently of optical losses. In this work, we investigate the concept of smart doping via material nanostructuring as a way to fabricate more efficient optical devices. This approach aims at optimizing the glass composition of the fiber core in order to use the minimal content of glass modifiers needed to reach the suited level of performances for EDFA. Er 3+-doped alumina nanoparticles (NPs), as precursor of Er 3+ ions in the preform fabrication process, were used to control the environment of rare-earth ions and their optical properties. Structural and optical characterizations of NP-doped preforms and optical fibers drawn from such preforms demonstrate the interest of this approach for small concentrations of aluminum in comparison to similar glass compositions obtained by a conventional technique.

  9. Benefit of Rare-Earth "Smart Doping" and Material Nanostructuring for the Next Generation of Er-Doped Fibers.

    Science.gov (United States)

    Savelii, Inna; Bigot, Laurent; Capoen, Bruno; Gonnet, Cedric; Chanéac, Corinne; Burova, Ekaterina; Pastouret, Alain; El-Hamzaoui, Hicham; Bouazaoui, Mohamed

    2017-12-01

    Erbium-doped fiber amplifiers (EDFAs) for harsh environments require to develop specific fabrication methods of Er (3+)-doped fibers (EDFs) so as to limit the impact of radiation-induced absorption. In this context, a compromise has to be found between the concentration of Erbium and the glass composition. On the one hand, high concentration of Er (3+) ions helps to reduce the length of the EDF and hence the cumulated attenuation but generally leads to luminescence quenching mechanisms that limit the performances. On the other hand, so as to avoid such quenching effect, glass modifiers like Al (3+) or P (5+) ions are used in the fabrication of commercial EDFs but are not suitable for applications in harsh environment because these glass modifiers are precursors of radiation-induced structural defects and consequently of optical losses. In this work, we investigate the concept of smart doping via material nanostructuring as a way to fabricate more efficient optical devices. This approach aims at optimizing the glass composition of the fiber core in order to use the minimal content of glass modifiers needed to reach the suited level of performances for EDFA. Er (3+)-doped alumina nanoparticles (NPs), as precursor of Er (3+) ions in the preform fabrication process, were used to control the environment of rare-earth ions and their optical properties. Structural and optical characterizations of NP-doped preforms and optical fibers drawn from such preforms demonstrate the interest of this approach for small concentrations of aluminum in comparison to similar glass compositions obtained by a conventional technique.

  10. Laser scribing of fluorine doped tin oxide for serial interconnection of CdS/CdTe solar cells

    OpenAIRE

    2015-01-01

    In thin film PV-module production the scribing of transparent conducting oxides, like fluorine doped tin oxides thin films, is performed with serial interconnection of solar cells without the use of external wires. This scribing is usually carried out with infrared and ultraviolet lasers, while for the other films that complete the solar cell structure, the scribing is performed with visible laser light. Thus, the use of only one laser in all scribing steps in the monolithic interconnection p...

  11. Frequency locking of an erbium-doped fiber ring laser to an external fiber Fabry-Perot resonator

    OpenAIRE

    Park, Namkyoo; Dawson, Jay W.; Vahala, Kerry J.

    1993-01-01

    An all-fiber, single-frequency, erbium-doped ring laser has been frequency locked to a resonance peak of an external fiber Fabry-Perot resonator by the Pound-Drever technique. In addition, feedback to the mode selection filter in the laser resonator eliminates occasional mode hopping completely, resulting in frequency-locked, stable, single-frequency operation of the laser for periods of several hours.

  12. Dual wavelength erbium-doped fiber laser with a lateral pressure-tuned Hi-Bi fiber Bragg grating

    Institute of Scientific and Technical Information of China (English)

    Lingyun Xiong(熊凌云); Guiyun Kai(开桂云); Lei Sun(孙磊); Xinhuan Feng(冯新焕); Chunxian Xiao(肖纯贤); Yange Liu(刘艳格); Shuzhong Yuan(袁树忠); Xiaoyi Dong(董孝义)

    2004-01-01

    Tunable dual wavelength erbium-doped fiber laser (EDFL) with stable oscillation at room temperature is proposed and demonstrated. This laser utilizes a Bragg grating fabricated in a high birefringence fiber as the wavelength-selective component, and then achieves the stable dual wavelength oscillation by introducing the polarization hole burning effect. Furthermore, by applying lateral strain upon the fiber Bragg grating (FBG), the space of the laser dual wavelengths can be tuned continuously.

  13. Stable multi-wavelength erbium-doped fiber laser based on dispersion-shifted fiber and Sagnac loop filter

    Institute of Scientific and Technical Information of China (English)

    Ying Gao; Daru Chen; Shiming Gao

    2007-01-01

    @@ A multi-wavelength erbium-doped fiber laser (MEDFL) with simple line structure is experimentally demonstrated by using a Sagnac interferometer as a comb filter. It is shown that the multi-wavelength lasing is quite stable at room temperature due to the four-wave mixing (FWM) effect among different laser channels in the dispersion-shifted fiber cooperated in the laser cavity.

  14. Laser cutting of laminated sheet material: a modeling exercise

    NARCIS (Netherlands)

    Graaf, de R.F.; Meijer, J.

    1997-01-01

    Laser cutting has been investigated for a number of aluminum-synthetic laminates, newly developed materials for the aeronautic and automotive industry. The materials consist of alternating aluminum and synthetic layers. It is shown that these materials can be cut at rates comparable to those of homo

  15. Laser cutting of laminated sheet material: a modeling exercise

    NARCIS (Netherlands)

    de Graaf, R.F.; Meijer, J.

    1997-01-01

    Laser cutting has been investigated for a number of aluminum-synthetic laminates, newly developed materials for the aeronautic and automotive industry. The materials consist of alternating aluminum and synthetic layers. It is shown that these materials can be cut at rates comparable to those of

  16. Charged particle and laser irradiation of selected materials

    Energy Technology Data Exchange (ETDEWEB)

    Svendsen, W.E.

    1996-11-01

    The main topics of the present thesis are the processes governing electronic sputtering of insulators and laser ablation of metals and insulators. The sputtering yield for electron bombardment of solid deuterium was investigated using quartz crystal microbalances as the measuring technique. The sputtering yield was measured with varying electron energy and deuterium film thickness. Laser ablation measurements of silver and nickel were carried out using a Nd:YAG laser. The effect of various experimental parameters such as background gas pressure (Ar, N{sub 2}), position of quartz crystals with respect to target position and the optimal number of laser shots for carrying out the experiments were investigated. The deposition rate was measured with varying laser wavelength and laser fluence. The angular distribution of the ablated material was measured for silver as well. A theoretical model based on the thermal properties of laser interaction with metals was applied in the initial phase of ablation. For the non-thermal processes governing laser interaction with the ablated plasma plume, a model developed by Phipps and Dreyfus was used to interpret the results. Laser ablation measurements of water-ice were carried using a Nitrogen laser. Attempts were made to measure the deposition rate for various the laser wavelengths and energies. (au) 8 tabs., 49 ills., 77 refs.

  17. Laser irradiation of carbon-tungsten materials

    Science.gov (United States)

    Marcu, A.; Avotina, L.; Marin, A.; Lungu, C. P.; Grigorescu, C. E. A.; Demitri, N.; Ursescu, D.; Porosnicu, C.; Osiceanu, P.; Kizane, G.; Grigoriu, C.

    2014-09-01

    Carbon-tungsten layers deposited on graphite by thermionic vacuum arc (TVA) were directly irradiated with a femtosecond terawatt laser. The morphological and structural changes produced in the irradiated area by different numbers of pulses were systematically explored, both along the spots and in their depths. Although micro-Raman and Synchrotron-x-ray diffraction investigations have shown no carbide formation, they have shown the unexpected presence of embedded nano-diamonds in the areas irradiated with high fluencies. Scanning electron microscopy images show a cumulative effect of the laser pulses on the morphology through the ablation process. The micro-Raman spatial mapping signalled an increased percentage of sp3 carbon bonding in the areas irradiated with laser fluencies around the ablation threshold. In-depth x-ray photoelectron spectroscopy investigations suggested a weak cumulative effect on the percentage increase of the sp2-sp3 transitions with the number of laser pulses just for nanometric layer thicknesses.

  18. Femtosecond laser induced phenomena in transparent solid materials

    DEFF Research Database (Denmark)

    Tan, D.Z.; Sharafudeen, K.N.; Yue, Yuanzheng

    2016-01-01

    The interaction of intense femtosecond laser pulses with transparent materials is a topic that has caused great interest of scientists over the past two decades. It will continue to be a fascinating field in the coming years. This is because many challenging fundamental problems have not been...... solved, especially concerning the interaction of strong, ultra-short electromagnetic pulses with matter, and also because potential advanced technologies will emerge due to the impressive capability of the intense femtosecond laser to create new material structures and hence functionalities. When......–matter interaction, and fabricate various integrated micro-devices. In recent years we have witnessed exciting development in understanding and applying femtosecond laser induced phenomena in transparent materials. The interaction of femtosecond laser pulses with transparent materials relies on non...

  19. Morphology Characterization of Uranium Particles From Laser Ablated Uranium Materials

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In the study, metallic uranium and uranium dioxide material were ablated by laser beam in order to simulate the process of forming the uranium particles in pyrochemical process. The morphology characteristic of uranium particles and the surface of

  20. Short-pulse laser interactions with disordered materials and liquids

    Energy Technology Data Exchange (ETDEWEB)

    Phinney, L.M.; Goldman, C.H.; Longtin, J.P.; Tien, C.L. [Univ. of California, Berkeley, CA (United States)

    1995-12-31

    High-power, short-pulse lasers in the picosecond and subpicosecond range are utilized in an increasing number of technologies, including materials processing and diagnostics, micro-electronics and devices, and medicine. In these applications, the short-pulse radiation interacts with a wide range of media encompassing disordered materials and liquids. Examples of disordered materials include porous media, polymers, organic tissues, and amorphous forms of silicon, silicon nitride, and silicon dioxide. In order to accurately model, efficiently control, and optimize short-pulse, laser-material interactions, a thorough understanding of the energy transport mechanisms is necessary. Thus, fractals and percolation theory are used to analyze the anomalous diffusion regime in random media. In liquids, the thermal aspects of saturable and multiphoton absorption are examined. Finally, a novel application of short-pulse laser radiation to reduce surface adhesion forces in microstructures through short-pulse laser-induced water desorption is presented.

  1. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Enhanced Laser Cooling of Rare-Earth-Ion-Doped Glass Containing Nanometer-Sized Metallic Particles

    Science.gov (United States)

    Jia, You-Hua; Zhong, Biao; Yin, Jian-Ping

    2009-03-01

    The enhanced laser cooling performance of rare-earth-ions-doped glasses containing small particles is predicted. This is achieved by the enhancement of local field around rare earth ions, owing to the surface plasmon resonance of small metallic particles. The role of energy transfer between ions and the particle is theoretical discussed. Depending on the particle size and the ion emission quantum efficiency, the enhancement of the absorption and the fluorescence is predicted. Moreover, taking Yb3+ -doped ZBLAN as example, the cooling power and heat-light converting efficiency are calculated. It is finally concluded that the absorption and the fluorescence are greatly enhanced in these composite materials, the cooling power is increased compared to the bulk material.

  2. Development of continuous glass melting for production of Nd-doped phosphate glasses for the NIF and LMJ laser system

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J. H.; Ficini-Dorn, G.; Hawley-Fedder, R.; McLean, M. J.; Suratwala, T.; Trombert, J. H.

    1998-08-14

    The NIF and LMJ laser systems require about 3380 and 4752 Nd-doped laser glass slabs, respectively. Continuous laser glass melting and forming will be used for the first time to manufacture these slabs. Two vendors have been chosen to produce the glass: Hoya Corporation and Schott Glass Technologies. The laser glass melting systems that each of these two vendors have designed, built and tested are arguably the most advanced in the world. Production of the laser glass will begin on a pilot scale in the fall of 1999.

  3. Development of continuous glass melting for production of Nd-doped phosphate glasses for the NIF and LMJ laser systems

    Science.gov (United States)

    Campbell, Jack H.; McLean, M. J.; Hawley-Fedder, Ruth A.; Suratwala, Tayyab I.; Ficini-Dorn, G.; Trombert, Jean-Hugues

    1999-07-01

    The NIF and LMJ laser systems require about 3380 and 4752 Nd-doped laser glass slabs, respectively. Continuous laser glass melting and forming will be used for the first time to manufacture these slabs. Two vendors have been chosen to produce the glass: Hoya Corporation and Schott Glass Technologies. The laser glass melting systems that each of these two vendors have designed, built and tested are arguably the most advanced in the world. Production of the laser glass will begin on a pilot scale in the fall of 1998.

  4. Millisecond laser machining of transparent materials assisted by a nanosecond laser with different delays.

    Science.gov (United States)

    Pan, Yunxiang; Lv, Xueming; Zhang, Hongchao; Chen, Jun; Han, Bing; Shen, Zhonghua; Lu, Jian; Ni, Xiaowu

    2016-06-15

    A millisecond laser combined with a nanosecond laser was applied to machining transparent materials. The influences of delay between the two laser pulses on processing efficiencies and modified sizes were studied. In addition, a laser-supported combustion wave (LSCW) was captured during laser irradiation. An optimal delay corresponding to the highest processing efficiency was found for cone-shaped cavities. The modified size as well as the lifetime and intensity of the LSCW increased with the delay decreasing. Thermal cooperation effects of defects, overlapping effects of small modified sites, and thermal radiation from LSCW result in all the phenomena.

  5. Laser Spectroscopy Investigations of Materials for Solid State Laser Systems.

    Science.gov (United States)

    1988-02-01

    Experimental geometry for anisotropic self-diffraction expert. Permanent address: Departamento de Optics y Estructura de Is Materia, mints. e refers to the...the helium-neon laser and PMT is the photo- "Permanent address: Departamento de Optics y Estructura de Ia Materia, multiplier tube. The results are sent

  6. Transient Infrared Measurement of Laser Absorption Properties of Porous Materials

    OpenAIRE

    Marynowicz Andrzej

    2016-01-01

    The infrared thermography measurements of porous building materials have become more frequent in recent years. Many accompanying techniques for the thermal field generation have been developed, including one based on laser radiation. This work presents a simple optimization technique for estimation of the laser beam absorption for selected porous building materials, namely clinker brick and cement mortar. The transient temperature measurements were performed with the use of infrared camera du...

  7. Laser spectroscopy of gas confined in nanoporous materials

    CERN Document Server

    Svensson, Tomas

    2009-01-01

    We show that high-resolution laser spectroscopy can probe surface interactions of gas confined in nano-cavities of porous materials. We report on strong line broadening and unfamiliar lineshapes due to tight confinement, as well as signal enhancement due to multiple photon scattering. This new domain of laser spectroscopy constitute a challenge for the theory of collisions and spectroscopic lineshapes, and open for new ways of analyzing porous materials and processes taking place therein.

  8. Isolator-free switchable uni- and bidirectional hybrid mode-locked erbium-doped fiber laser.

    Science.gov (United States)

    Chernysheva, Maria; Araimi, Mohammed Al; Kbashi, Hani; Arif, Raz; Sergeyev, Sergey V; Rozhin, Aleksey

    2016-07-11

    An Erbium-doped fibre ring laser hybrid mode-locked with single-wall carbon nanotubes (SWNT) and nonlinear polarisation evolution (NPE) without an optical isolator has been investigated for various cavity conditions. Precise control of the state of polarisation (SOP) in the cavity ensures different losses for counter-propagating optical fields. As the result, the laser operates in quasi-unidirectional regime in both clockwise (CW) and counter-clockwise (CCW) directions with the emission strengths difference of the directions of 22 dB. Furthermore, by adjusting the net birefringence in the cavity, the laser can operate in a bidirectional generation. In this case, a laser pumped with 75 mW power at 980 nm generates almost identical 790 and 570 fs soliton pulses with an average power of 1.17 and 1.11 mW. The operation stability and pulse quality of the soliton pulses in both unidirectional regimes are highly competitive with those generated in conventional ring fibre lasers with isolator in the cavity. Demonstrated bidirectional laser operation can find vital applications in gyroscopes or precision rotation sensing technologies.

  9. Surface studies on benzophenone doped PDMS microstructures fabricated using KrF excimer laser direct write lithography

    Energy Technology Data Exchange (ETDEWEB)

    Kant, Madhushree Bute; Shinde, Shashikant D. [Department of Physics, University of Pune, Pune 411007 (India); Bodas, Dhananjay [Centre for Nanobioscience, Agharkar Research Institute, Agharkar road, Pune 411004 (India); Patil, K.R. [Center for Materials Characterization, National Chemical Laboratories, Pune 411008 (India); Sathe, V.G. [UGC DAE Inter University Consortium, Indore 452017 (India); Adhi, K.P. [Department of Physics, University of Pune, Pune 411007 (India); Gosavi, S.W., E-mail: swg@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411007 (India)

    2014-09-30

    Graphical abstract: - Highlights: • Use of KrF Laser micromachining for Lab-On-Chip applications at lower fluence. • Addition of Benzophenone in PDMS enhances its self development sensitivity. • Benzophenone helps efficient energy transfer for equal density of bond scissioning. • Correlation of chemical composition with laser dose and microstructure. • Microstructures with well defined clean sidewalls. - Abstract: This paper discusses microfabrication process for benzophenone doped polydimethylsiloxane (PDMS) using laser lithography. KrF excimer laser of 248 nm with 20 ns pulse width at repetition rate of 1 Hz was used for microfabrication of undoped and benzophenone doped PDMS. The doped-PDMS shows sensitivity below 365 nm, permitting processing under ambient light. The analysis of etch depth revealed that doped PDMS shows self developable sensitivity at lower fluence of ∼250 mJ/cm{sup 2}. The unexposed and exposed surface was studied using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and Scanning electron microscopy (SEM). Spectrocopic analysis indicated increase in C-O, C=O, Si-O{sub 3} and Si-O{sub 4} bonding at the expense of Si-C and Si-O{sub 2} bonds of PDMS. In case of laser exposed doped-PDMS, removal of benzophenone from probe depth of spectroscopy was observed. Whereas the surface morphology of exposed and unexposed doped-PDMS was observed to be same, indicating clean development of PDMS micropatterns. The present study indicates that addition of 3.0 wt.% benzophenone in PDMS enhance self development sensitivity of PDMS. The self developable results on doped-PDMS are quite encouraging for its potential use in point of care Lab-On-Chip applications, for fabricating micropatterns using direct write laser lithography technology.

  10. Two-photon–induced internal modification of silicon by erbium-doped fiber laser

    NARCIS (Netherlands)

    Verburg, P.C.; Römer, Gerardus Richardus, Bernardus, Engelina; Huis in 't Veld, Bert

    2014-01-01

    Three-dimensional bulk modification of dielectric materials by multiphoton absorption of laser pulses is a well-established technology. The use of multiphoton absorption to machine bulk silicon has been investigated by a number of authors using femtosecond laser sources. However, no modifications

  11. Computational dynamics of laser alloyed metallic materials for improved corrosion performance: computational dynamics of laser alloyed metallic materials

    CSIR Research Space (South Africa)

    Fatoba, OS

    2016-04-01

    Full Text Available Laser alloying is a material processing method which utilizes the high power density available from defocused laser beam to melt both metal coatings and a part of the underlying substrate. Since melting occur solitary at the surface, large...

  12. Crystal-Field Engineering of Solid-State Laser Materials

    Science.gov (United States)

    Henderson, Brian; Bartram, Ralph H.

    2005-08-01

    This book examines the underlying science and design of laser materials. It emphasizes the principles of crystal-field engineering and discusses the basic physical concepts that determine laser gain and nonlinear frequency conversion in optical crystals. Henderson and Bartram develop the predictive capabilities of crystal-field engineering to show how modification of the symmetry and composition of optical centers can improve laser performance. They also discuss applications of the principles of crystal-field engineering to a variety of optical crystals in relation to the performances of laser devices. This book will be of considerable interest to physical, chemical and material scientists and to engineers involved in the science and technology of solid state lasers.

  13. Material, Mechanical, and Tribological Characterization of Laser-Treated Surfaces

    Science.gov (United States)

    Yilbas, Bekir Sami; Kumar, Aditya; Bhushan, Bharat; Aleem, B. J. Abdul

    2014-10-01

    Laser treatment under nitrogen assisting gas environment of cobalt-nickel-chromium-tungsten-based superalloy and high-velocity oxygen-fuel thermal spray coating of nickel-chromium-based superalloy on carbon steel was carried out to improve mechanical and tribological properties. Superalloy surface was preprepared to include B4C particles at the surface prior to the laser treatment process. Material and morphological changes in the laser-treated samples were examined using scanning electron microscopy, energy-dispersive spectroscopy, and x-ray diffraction (XRD) analysis. Residual stresses present at the surface region of the laser-treated layer were determined from the XRD data. The microhardness of the laser-treated surface was measured by indentation tests. Fracture toughness of the coating surfaces before and after laser treatment were also measured using overload indentation tests. Macrowear and macrofriction characterization were carried out using pin-on-disk tests.

  14. Femtosecond laser pulse train interaction with dielectric materials

    CERN Document Server

    Caulier, O Dematteo; Chimier, B; Skupin, S; Bourgeade, A; Léger, C Javaux; Kling, R; Hönninger, C; Lopez, J; Tikhonchuk, V; Duchateau, G

    2015-01-01

    We investigate the interaction of trains of femtosecond microjoule laser pulses with dielectric materials by means of a multi-scale model. Our theoretical predictions are directly confronted with experimental observations in soda-lime glass. We show that due to the low heat conductivity, a significant fraction of the laser energy can be accumulated in the absorption region. Depending on the pulse repetition rate, the material can be heated to high temperatures even though the single pulse energy is too low to induce a significant material modification. Regions heated above the glass transition temperature in our simulations correspond very well to zones of permanent material modifications observed in the experiments.

  15. Femtosecond laser processing of fuel injectors - a materials processing evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, B C; Wynne, A

    2000-12-16

    Lawrence Livermore National Laboratory (LLNL) has developed a new laser-based machining technology that utilizes ultrashort-pulse (0.1-1.0 picosecond) lasers to cut materials with negligible generation of heat or shock. The ultrashort pulse laser, developed for the Department of Energy (Defense Programs) has numerous applications in operations requiring high precision machining. Due to the extremely short duration of the laser pulse, material removal occurs by a different physical mechanism than in conventional machining. As a result, any material (e.g., hardened steel, ceramics, diamond, silicon, etc.) can be machined with minimal heat-affected zone or damage to the remaining material. As a result of the threshold nature of the process, shaped holes, cuts, and textures can be achieved with simple beam shaping. Conventional laser tools used for cutting or high-precision machining (e.g., sculpting, drilling) use long laser pulses (10{sup -8} to over 1 sec) to remove material by heating it to the melting or boiling point (Figure 1.1a). This often results in significant damage to the remaining material and produces considerable slag (Figure 1.2a). With ultrashort laser pulses, material is removed by ionizing the material (Figure 1.1b). The ionized plasma expands away from the surface too quickly for significant energy transfer to the remaining material. This distinct mechanism produces extremely precise and clean-edged holes without melting or degrading the remaining material (Figures 1.2 and 1.3). Since only a very small amount of material ({approx} <0.5 microns) is removed per laser pulse, extremely precise machining can be achieved. High machining speed is achieved by operating the lasers at repetition rates up to 10,000 pulses per second. As a diagnostic, the character of the short-pulse laser produced plasma enables determination of the material being machined between pulses. This feature allows the machining of multilayer materials, metal on metal or metal on

  16. In vivo implantation of porous titanium alloy implants coated with magnesium-doped octacalcium phosphate and hydroxyapatite thin films using pulsed laser depostion.

    Science.gov (United States)

    Mróz, Waldemar; Budner, Bogusław; Syroka, Renata; Niedzielski, Kryspin; Golański, Grzegorz; Slósarczyk, Anna; Schwarze, Dieter; Douglas, Timothy E L

    2015-01-01

    The use of porous titanium-based implant materials for bone contact has been gaining ground in recent years. Selective laser melting (SLM) is a rapid prototyping method by which porous implants with highly defined external dimensions and internal architecture can be produced. The coating of porous implants produced by SLM with ceramic layers based on calcium phosphate (CaP) remains relatively unexplored, as does the doping of such coatings with magnesium (Mg) to promote bone formation. In this study, Mg-doped coatings of the CaP types octacalcium phosphate and hydroxyapatite (HA) were deposited on such porous implants using the pulsed laser deposition method. The coated implants were subsequently implanted in a rabbit femoral defect model for 6 months. Uncoated implants served as a reference material. Bone-implant contact and bone volume in the region of interest were evaluated by histopathological techniques using a tri-chromatographic Masson-Goldner staining method and by microcomputed tomography (µCT) analysis of the volume of interest in the vicinity of implants. Histopathological analysis revealed that all implant types integrated directly with surrounding bone with ingrowth of newly formed bone into the pores of the implants. Biocompatibility of all implant types was demonstrated by the absence of inflammatory infiltration by mononuclear cells (lymphocytes), neutrophils, and eosinophils. No osteoclastic or foreign body reaction was observed in the vicinity of the implants. µCT analysis revealed a significant increase in bone volume for implants coated with Mg-doped HA compared to uncoated implants.

  17. Nitrogen-doped carbons in Li-S batteries: materials design and electrochemical mechanism

    Directory of Open Access Journals (Sweden)

    Xia eLi

    2014-11-01

    Full Text Available Li-S batteries have been considered as next generation Li batteries due to their high theoretical energy density. Over the past few years, researchers have made significant efforts in breaking through critical bottlenecks which impede the commercialization of Li-S batteries. Beginning with a basic introduction to Li-S systems and their associated mechanism, this review will highlight the application of one specific carbon family, nitrogen-doped carbon materials in sulfur based cathodes. These materials will include nitrogen doped porous carbon, carbon nanotubes, nanofibers and graphene. The article will conclude with a summary of recent research efforts in this field as well as the future prospects for the use of nitrogen-doped carbon materials in Li-S batteries.

  18. Pulsed Laser Deposited Nickel Doped Zinc Oxide Thin Films: Structural and Optical Investigations

    Directory of Open Access Journals (Sweden)

    Tanveer A. Dar

    2013-05-01

    Full Text Available Structural and optical studies has been done on Nickel doped Zinc Oxide (NixZn1 – xO, x  0.03, 0.05 and 0.07 by weight thin films prepared by pulsed laser deposition technique. The films are characterized by X-ray diffraction, Uv-vis spectroscopy, X-ray photoelectron spectroscopy. We observed a slight red shift in the optical band gap in the NiZnO subsequent to Ni doping. This shift can be assigned due to the sp-d exchange interaction of Ni- d states with s and p-states of ZnO. Also X-ray photoelectron spectroscopy studies show that Ni has well substituted in + 2 oxidation state by replacing Zn2+.

  19. Synthesis and characterization of rare earth doped novel optical materials and their potential applications

    Science.gov (United States)

    Pokhrel, Madhab

    There are many application of photonic materials but selection of photonic materials are always constrained by number of factors such as cost, availability of materials, thermal and chemical stability, toxicity, size and more importantly ease of synthesis and processing along with the efficient emission. For example, quantum dots are efficient emitter but they are significantly toxic, whereas dyes are also efficient emitters but they are chemically unstable. On the other hand, display and LED requires the micron size particles but bio application requires the nano-sized particles. On the other hand, laser gain media requires the ceramics glass or single crystal not the nanoparticles. So, realization of practical optical systems critically depends on suitable materials that offer specific combinations of properties. Solid-state powders such as rare-earth ions doped nano and micron size phosphors are one of the most promising candidates for several photonic applications discussed above. In this dissertation, we investigate the upconversion (UC) fluorescence characteristics of rare earth (RE) doped M2O2S (M = Y, Gd, La) oxysulphide phosphors, for near-infrared to visible UC. Both nano and micron size phosphors were investigated depending on their applications of interest. This oxysulphide phosphor possesses several excellent properties such as chemical stability, low toxicity and can be easily mass produced at low cost. Mainly, Yb3+, Er3+, and Ho3+ were doped in the host lattice, resulting in bright red, green, blue and NIR emissions under 980 nm and 1550 nm excitation at various excitation power densities. Maximum UC quantum yields (QY) up to 6.2 %, 5.8%, and 4.6% were respectively achieved in Yb3+/Er3+ :La2O2S, Y2O2S, and Gd2O 2S. Comparisons have been made with respect to reported most efficient upconverting phosphors beta-NaYF4:20 % Yb/ 2% Er. We believe that present phosphors are the most efficient and lower excitation threshold upconverting phosphors at 980 and

  20. Early dynamics of guest-host interaction in dye-doped liquid crystalline materials.

    Science.gov (United States)

    Truong, Thai V; Xu, Lei; Shen, Y R

    2003-05-16

    We have studied in detail the early dynamics of laser-induced molecular reorientation in a dye-doped liquid crystalline (LC) medium that exhibits a significant enhancement of the optical Kerr nonlinearity due to guest-host interaction. Experimental results agree quantitatively with theory based on a model in which the anisotropic dye excitation helps reorient the LC molecules through a mean-field intermolecular interaction.

  1. 575 nm laser oscillation in Dy3+-doped waterproof fluoro-aluminate glass fiber pumped by violet GaN laser diodes

    Science.gov (United States)

    Fujimoto, Yasushi; Ishii, Osamu; Yamazaki, Masaaki

    2011-02-01

    We successfully drew a low-loss Dy-doped optical fiber (0.3dB/m at 532nm) of a waterproof fluoro-aluminate glass system and demonstrated yellow laser oscillation in the Dy3+-doped fluoride fiber pumped by a 398.8-nm GaN laser diode. The maximum output power was 10.3 mW and the slope efficiency was 17.1% at 575 nm. Since the fluoro-aluminate- glass system has a remarkable water resistance advantage compared to ZBLAN glass, Dy-doped fluoro-aluminate glass fiber is expected to contribute to making a solid-state yellow fiber laser with high chemical durability without a frequency doubling technique.

  2. Laser interaction with biological material mathematical modeling

    CERN Document Server

    Kulikov, Kirill

    2014-01-01

    This book covers the principles of laser interaction with biological cells and tissues of varying degrees of organization. The problems of biomedical diagnostics are considered. Scattering of laser irradiation of blood cells is modeled for biological structures (dermis, epidermis, vascular plexus). An analytic theory is provided which is based on solving the wave equation for the electromagnetic field. It allows the accurate analysis of interference effects arising from the partial superposition of scattered waves. Treated topics of mathematical modeling are: optical characterization of biological tissue with large-scale and small-scale inhomogeneities in the layers, heating blood vessel under laser irradiation incident on the outer surface of the skin and thermo-chemical denaturation of biological structures at the example of human skin.

  3. Material measurement method based on femtosecond laser plasma shock wave

    Science.gov (United States)

    Zhong, Dong; Li, Zhongming

    2017-03-01

    The acoustic emission signal of laser plasma shock wave, which comes into being when femtosecond laser ablates pure Cu, Fe, and Al target material, has been detected by using the fiber Fabry-Perot (F-P) acoustic emission sensing probe. The spectrum characters of the acoustic emission signals for three kinds of materials have been analyzed and studied by using Fourier transform. The results show that the frequencies of the acoustic emission signals detected from the three kinds of materials are different. Meanwhile, the frequencies are almost identical for the same materials under different ablation energies and detection ranges. Certainly, the amplitudes of the spectral character of the three materials show a fixed pattern. The experimental results and methods suggest a potential application of the plasma shock wave on-line measurement based on the femtosecond laser ablating target by using the fiber F-P acoustic emission sensor probe.

  4. Picosecond and femtosecond lasers for industrial material processing

    Science.gov (United States)

    Mayerhofer, R.; Serbin, J.; Deeg, F. W.

    2016-03-01

    Cold laser materials processing using ultra short pulsed lasers has become one of the most promising new technologies for high-precision cutting, ablation, drilling and marking of almost all types of material, without causing unwanted thermal damage to the part. These characteristics have opened up new application areas and materials for laser processing, allowing previously impossible features to be created and also reducing the amount of post-processing required to an absolute minimum, saving time and cost. However, short pulse widths are only one part of thee story for industrial manufacturing processes which focus on total costs and maximum productivity and production yield. Like every other production tool, ultra-short pulse lasers have too provide high quality results with maximum reliability. Robustness and global on-site support are vital factors, as well ass easy system integration.

  5. Efficient single-mode operation of a cladding-pumped ytterbium-doped helical-core fiber laser.

    Science.gov (United States)

    Wang, P; Cooper, L J; Sahu, J K; Clarkson, W A

    2006-01-15

    A novel approach to achieving robust single-spatial-mode operation of cladding-pumped fiber lasers with multimode cores is reported. The approach is based on the use of a fiber geometry in which the core has a helical trajectory within the inner cladding to suppress laser oscillation on higher-order modes. In a preliminary proof-of-principle study, efficient single-mode operation of a cladding-pumped ytterbium-doped helical-core fiber laser with a 30 microm diameter core and a numerical aperture of 0.087 has been demonstrated. The laser yielded 60.4 W of output at 1043 nm in a beam with M2 diode stack at 976 nm. The slope efficiency at pump powers well above threshold was approximately 84%, which compares favorably with the slope efficiencies achievable with conventional straight-core Yb-doped double-clad fiber lasers.

  6. A computational model for heterogeneous heating during pulsed laser irradiation of polymers doped with light-absorbing microparticles

    DEFF Research Database (Denmark)

    Marla, Deepak; Zhang, Yang; Jabbaribehnam, Mirmasoud

    2016-01-01

    Doping of polymers with light-absorbing microparticles to increase their optical properties is a commonly used pre-treatment technique in laser processing of polymers. The presence of these particles plays an important role during laser heating of the polymer that influences its surface...... characteristics. This work presents a study based on a computational model of laser heating of polymer doped with light-absorbing microparticles accounting for the heterogeneous nature of heating. The work aims at gaining a fundamental insight into the nature of the heating process and to understand the role...... of microparticles. The results suggest that apart from the laser intensity and pulse duration, the properties of the microparticles including their size and distribution also play an important role during the laser heating of polymers....

  7. Analysis of dual-end-pumped Nd3+-doped index-crossover gain guided-index antiguided fiber laser

    Science.gov (United States)

    Shen, Xiao; Wei, Wei; Zou, Hui; Zhang, Liaolin

    2016-05-01

    A dual-end pumped Nd3+-doped index-crossover gain guided-index antiguided (IGG-IAG) fiber laser is analyzed in theory. Pump light propagation and output laser characteristics are both explored by solving the related rate equations. Simulation results show that pump power confined in the IGG-IAG fiber core is larger and more uniform than that of the gain-guided and index-antiguided(GG-IAG) fiber, and the optimum fiber length and the output power of the IGG-IAG fiber laser are both larger than that of GG-IAG fiber laser. The relationship between threshold pump power and doped concentration, fiber length, fiber radius is researched respectively. The analysis results give out a method for the optimal design of the IGG-IAG fiber laser.

  8. Interaction of pulsed CO2 laser radiation with optical materials

    Science.gov (United States)

    Schmitt, Ruediger; Hugenschmidt, Manfred; Geiss, L.; Stechele, E.

    1995-03-01

    Pulsed high power CO2-laser irradiation can cause damage to optical materials. Some results obtained at ISL with a repetitively pulsed CO2-laser with pulse energies up to 24 J are presented in this paper. In production facilities with CO2-lasers, optics transmitting in the visible spectral range like glass or PMMA are used as protection windows against scattered light. These materials have small skin depths for electromagnetic waves at 10,6 micrometers , typically in the order of some micrometers , so the interaction takes place in thin surface layers. Under high power laser radiation the transparency of the optics is lowered. On the other hand infrared transmitting optics like KCl or ZnSe show a low intrinsic absorption for CO2-laser radiation. Theoretical estimations matching with the experimental observations showed, however, that strong heating occurs, if a thin layer of inhomogeneities, typically some micrometers thick, is included in the surrounding material with slightly higher absorption than the surrounding lowless material. Under these assumptions the thermally induced stress inside the materials can explain the experimentally observed mechanical damage. Besides these thermal damage effects mechanical momenta are transferred by pulsed laser radiation to the optics. Experimental results as obtained by a ballistic pendulum are reported.

  9. Low thermal budget n-type doping into Ge(001) surface using ultraviolet laser irradiation in phosphoric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Kouta, E-mail: ktakahas@alice.xtal.nagoya-u.ac.jp, E-mail: kurosawa@alice.xtal.nagoya-u.ac.jp; Sakashita, Mitsuo; Takeuchi, Wakana; Nakatsuka, Osamu [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Kurosawa, Masashi, E-mail: ktakahas@alice.xtal.nagoya-u.ac.jp, E-mail: kurosawa@alice.xtal.nagoya-u.ac.jp [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Institute of Materials and Systems for Sustainability, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Ikenoue, Hiroshi [Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Zaima, Shigeaki [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Institute of Materials and Systems for Sustainability, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2016-02-01

    We have investigated phosphorus (P) doping into Ge(001) surfaces by using ultraviolet laser irradiation in phosphoric acid solution at room temperature. We demonstrated that the diffusion depth of P in Ge and the concentration of electrically activated P can be controlled by the number of laser shots. Indeed, a high concentration of electrically activated P of 2.4 × 10{sup 19} cm{sup −3} was realized by 1000-times laser shots at a laser energy of 1.0 J/cm{sup 2}, which is comparable or better than the counterparts of conventional n-type doping using a high thermal budget over 600 °C. The generation current is dominant in the reverse bias condition for the laser-doped pn-junction diodes independent on the number of laser shots, thus indicating low-damage during the pn-junction formation. These results open up the possibility for applicable low thermal budget doping process for Ge-based devices fabricated on flexible substrates as well as Si electronics.

  10. Surface plasmon waveguides with gradually doped or NiAl intermetallic compound buried contact for terahertz quantum cascade lasers

    Science.gov (United States)

    Indjin, D.; Ikonić, Z.; Harrison, P.; Kelsall, R. W.

    2003-09-01

    Improved designs of surface plasmon waveguides for use in GaAs/AlGaAs terahertz quantum cascade lasers are presented. Modal losses and confinement factors are calculated for TM modes in metal-variably doped multilayer semiconductor and metal-intermetallic compound layer clad structures and compared with those obtained in recently realized metal-highly doped semiconductor clad layer structures. Considerable improvements of the mode confinement factors are predicted, and guidelines for choosing the confinement layer parameters are given.

  11. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials

    OpenAIRE

    2015-01-01

    Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase....

  12. The thickness design of unintentionally doped GaN interlayer matched with background doping level for InGaN-based laser diodes

    Directory of Open Access Journals (Sweden)

    P. Chen

    2016-03-01

    Full Text Available In order to reduce the internal optical loss of InGaN laser diodes, an unintentionally doped GaN (u-GaN interlayer is inserted between InGaN/GaN multiple quantum well active region and Al0.2Ga0.8N electron blocking layer. The thickness design of u-GaN interlayer matching up with background doping level for improving laser performance is studied. It is found that a suitably chosen u-GaN interlayer can well modulate the optical absorption loss and optical confinement factor. However, if the value of background doping concentration of u-GaN interlayer is too large, the output light power may decrease. The analysis of energy band diagram of a LD structure with 100 nm u-GaN interlayer shows that the width of n-side depletion region decreases when the background concentration increases, and may become even too small to cover whole MQW, resulting in a serious decrease of the output light power. It means that a suitable interlayer thickness design matching with the background doping level of u-GaN interlayer is significant for InGaN-based laser diodes.

  13. IGNITING SHS BY LASER AND ITS APPLICATION TO SELECTIVE LASER SINTERING OF METALLIC POWDER MATERIAL

    Institute of Scientific and Technical Information of China (English)

    Y.S.Shi; S.C.Chen; X.L.Lu; S.H.Huang

    2004-01-01

    How to directly fabricate metallic functional parts with selective laser sintering (SLS) process is a potential technique that scientists are researching. Existent problems during directly fabricating metal part by use of SLS are analyzed. For the sake of solving the problems, a new idea of adding self-propagating high-temperature synthesis (SHS) material into metallic powder material to form new type of SLS metallic powder material is put forward. This powder material can release controllable amount of heat during its interaction with the laser beam energy to reduce the requirement to laser power during directly sintering metallic part, to prolong the time of metallic liquid phase existing, and to improve the intensity and accuracy of SLS part. For this reason, SHS material's interaction with the C02 laser beam energy is researched, which proves that CO2 laser beam energy may instantly ignite SHS reaction. On the basis of the above-mentioned researches, the effect of sintering the metal powder material mixing SHS material with CO2 laser is also researched,which shows: there is an optimal blending ratio of various material in the new metallic powder material. Under the optimal blending ratio and SLS process parameters, this new metallic powder material can indeed release amount of heat and SHS reaction may be controlled within the laser sintering. This research result makes it possible that the metallic part is directly sintered with small C02 laser (less than 50W), which may greatly reduce the volume, cost and running expenditure of SLS machine, be propitious to application.

  14. VUV spectroscopy of nominally pure and rare-earth ions doped LiCaAIF6 single crystals as promising materials for 157 nm photolithography

    Science.gov (United States)

    Cefalas, Alkiviadis C.; Sarantopoulou, Evangelia; Kollia, Z.; Abdulsabirov, R. Y.; Korableva, S. L.; Naumov, A. K.; Semashko, V. V.; Kobe, S.; McGuiness, P. J.

    2002-07-01

    Recently it was found that birefringence is induced in CaF2 crystals when they are illuminated with laser light at 157 nm. Taking into consideration that CaF2 is the only optical material used in 157 nm photolithography today, the possibility to use new wide band gap fluoride crystals as optical elements for 157 nm photolithography, even those of non-cubic symmetry, should be considered. Additionally fluoride dielectric crystals with wide band gaps doped with trivalent rare-earth (RE) ions can be used as passive or active optical elements int eh VUV. For doped crystals, applications depend on the structure of the energy level pattern of the 4fn-15d electronic configuration and RE ion concentration. In this work we are exploiting the use of wide band gap fluoride dielectric crystals doped with RE ions. The laser induced fluorescence spectrum at 157 nm, and the absorption spectra of the LiCaAlF6 crystals, pure and doped with RE ions, were investigated in the VUV region of the spectrum. A new m4tehod for monitoring RE concentration in wide band gap fluoride crystals, that is based on vibrating sample magnetometer measurement is presented as well.

  15. Mathematical Modelling of Laser/Material Interactions.

    Science.gov (United States)

    1983-11-25

    translated to the model input. Even an experimental mode print can also be digitalised for the model. In trying to describe high order modes matliematically...4. Mazumder J. Steen W.M. "Welding of Ti 6al - 4V by continuous wave CO2 laser". Metal construction Sept. 1980 pp423 - 427. 5. Kogelnik H, Li.T Proc

  16. Treatment of dilated pores with 1410-nm fractional erbium-doped fiber laser.

    Science.gov (United States)

    Suh, Dong-Hye; Chang, Ka-Yeun; Lee, Sang-Jun; Song, Kye-Yong; Choi, Jeong Hwee; Shin, Min Kyung; Jeong, Ki-Heon

    2015-04-01

    Dilated pores can be an early sign of skin aging and are a significant cosmetic concern. The 1410-nm wavelength is optimal for superficial dermal treatments up to 650 μm deep. The aim of the present study was to evaluate the clinical effectiveness and safety of the fractional erbium-doped fiber 1410-nm laser in the treatment of dilated pores. Fifteen patients with dilated facial pores underwent three laser treatments at 3-week intervals. Posttreatment skin responses and side effects were assessed at treatment and follow-up visits by study physicians. Clinical effectiveness of treatment was assessed by both study physicians and patients 3 months after the final laser treatment using a quartile grading scale. Histological examination was performed using biopsy samples taken at baseline (pretreatment) and 3 months after the last treatment. This study showed that greater than 51 % improvement in dilated pores was demonstrated in 14 of 15 patients after three sessions of laser treatments. Improvements in skin texture, tone, and smoothness were reported in all patients. Treatment was well tolerated in all patients, with no unanticipated side effects. This study demonstrates that the 1410-nm fractional erbium fiber laser is effective and safe for treatment of dilated facial pores in Fitzpatrick skin types III-IV.

  17. Modelling of short-wavelength operation of Nd 3+ doped fluorozirconate glass fiber laser

    Science.gov (United States)

    Klimczak, M.; Witonski, P.; Ryter, A.; Piramidowicz, R.

    2006-03-01

    In this paper we analyze the threshold violet and ultra-violet laser operation in Nd 3+ doped ZBLAN fibers, using relatively fast and accurate method, based on measured spectroscopic parameters like fluorescence lifetimes and emissiod/absorption cross-sections spectra. Our approach, which is based on energy theorem and threshold field approximation, extends the model presented in [1] by taking into account the longitudinal and transverse field distribution of the fiber laser mode. Specifically, in this work we compare the efficiency of two possible laser pumping schemes: direct and two-photon excitation. The problem of laser resonator optimization is discussed by providing the analytical formulas for small signal gain in active fiber medium as a function of structure parameters i.e. the cavity geometry, distributed losses of the active medium, output power level and the mirror reflectivity. As the result of the carried-out optimizations we can determine the conditions for obtaining short-wavelength lasing in Nd:ZBLAN fiber laser with minimal threshold and maximal output power level.

  18. Pulse formation and characteristics of the cw mode-locked titanium-doped sapphire laser

    Science.gov (United States)

    Zschocke, Wolfgang; Stamm, Uwe; Heumann, Ernst; Ledig, Mario; Guenzel, Uwe; Kvapil, Jiri; Koselja, Michael P.; Kubelka, Jiri

    1991-10-01

    We report on measurements of transient and steady-state pulse characteristics of an acousto- optically mode-locked titanium-doped sapphire laser. During the pulse evolution, oscillations in the pulse width and pulse energy are found. A steady state is reached after about 40 to 60 microsecond(s) . The steady-state pulse width is strongly influenced by the mode-locking loss as well as the intracavity bandwidth. Shortest pulses of typically 15 ps are obtained. The experiment is compared with results of a simple computer simulation.

  19. Generating few-cycle pulses for nanoscale photoemission easily with an erbium-doped fiber laser.

    Science.gov (United States)

    Thomas, Sebastian; Holzwarth, Ronald; Hommelhoff, Peter

    2012-06-18

    We demonstrate a simple setup capable of generating four-cycle pulses at a center wavelength of 1700 nm for nanoscale photoemission. Pulses from an amplified erbium-doped fiber laser are spectrally broadened by propagation through a highly non-linear fiber. Subsequently, we exploit dispersion in two different types of glass to compress the pulses. The pulse length is estimated by measuring an interferometric autocorrelation trace and comparing it to a numerical simulation. We demonstrate highly non-linear photoemission of electrons from a nanometric tungsten tip in a hitherto unexplored pulse parameter range.

  20. Erbium-doped yttrium aluminium garnet ablative laser treatment for endogenous ochronosis.

    Science.gov (United States)

    Chaptini, Cassandra; Huilgol, Shyamala C

    2015-08-01

    Ochronosis is a rare disease characterised clinically by bluish-grey skin discolouration and histologically by yellow-brown pigment deposits in the dermis. It occurs in endogenous and exogenous forms. Endogenous ochronosis, also known as alkaptonuria, is an autosomal recessive disease of tyrosine metabolism, resulting in the accumulation and deposition of homogentisic acid in connective tissue. We report a case of facial endogenous ochronosis and coexistent photodamage, which was successfully treated with erbium-doped yttrium aluminium garnet laser resurfacing and deep focal point treatment to remove areas of residual deep pigment.

  1. Pulsed laser deposition of gadolinia doped ceria layers at moderate temperature – a seeding approach

    DEFF Research Database (Denmark)

    Rodrigo, Katarzyna Agnieszka; Heiroth, Sebastian; Pryds, Nini

    ), to the growth of dense, gas impermeable 10 mol% gadolinia-doped ceria (CGO10) solid electrolyte can be overcome by the seeding process. In order to evaluate the seed layer preparation, the effects of different thermal annealing treatments on the morphology, microstructure and surface roughness of ultrathin CGO...... the preparation of ultrathin seed layers in the first stage of the deposition process is often envisaged to control the growth and physical properties of the subsequent coating. This work suggests that the limitations of conventional pulsed laser deposition (PLD), performed at moderate temperature (400°C...

  2. Epitaxial growth of atomically flat gadolinia-doped ceria thin films by pulsed laser deposition

    DEFF Research Database (Denmark)

    Chen, Yunzhong; Pryds, Nini; Schou, Jørgen

    ), to the growth of dense, gas impermeable 10 mol% gadolinia-doped ceria (CGO10) solid electrolyte can be overcome by the seeding process. In order to evaluate the seed layer preparation, the effects of different thermal annealing treatments on the morphology, microstructure and surface roughness of ultrathin CGO...... the preparation of ultrathin seed layers in the first stage of the deposition process is often envisaged to control the growth and physical properties of the subsequent coating. This work suggests that the limitations of conventional pulsed laser deposition (PLD), performed at moderate temperature (400°C...

  3. Reverse horseshoe and spiral templates in an erbium-doped fiber laser

    Science.gov (United States)

    Used, Javier; Martín, Juan Carlos

    2009-04-01

    Time series obtained from the emission of an erbium-doped fiber ring laser with sine-wave pump modulation have been analyzed in order to determine the topological structure of the underlying chaotic attractor. With appropriate modulation conditions, topological structures not often observed in experimental systems have been found: the reverse horseshoe and the spiral template. The method employed for template determination is not conventional as it takes profit of the high dissipation of the system, which allows one to simplify dramatically the general procedure of analysis.

  4. A unidirectional multiwavelength erbium-doped fiber ring laser without isolator at room temperature

    Science.gov (United States)

    Sun, Guoyong; Qu, Ronghui; Yang, Jing; Wang, Xiangzhao; Fang, Zujie

    2005-01-01

    Highly uniform multiwavelength erbium-doped fiber ring laser with a sinusoidal phase modulator and line intervals of 0.45 nm is demonstrated. The flat and stable output distribution is realized by optimizing modulation voltage and frequency for the sine phase modulator. Simultaneous 30 lasing lines are obtained in power difference less than 2 dB. In addition, the implemented cavity structure can support unidirectional operation even without optical isolators. The power difference between clockwise and counterclockwise direction is higher than 20 dB, almost independent of pumping powers and lasing wavelengths in lasing operation.

  5. Sub-50-fs pulse generation from thulium-doped ZBLAN fiber laser oscillator.

    Science.gov (United States)

    Nomura, Yutaka; Fuji, Takao

    2014-05-19

    An ultrafast, passively mode-locked fiber laser oscillator has been realized using thulium-doped ZBLAN fibers. Very low dispersion of ZBLAN glass fibers enabled generation of pulses with broad spectra extending from 1730 nm to 2050 nm. Pulses are obtained with the average power of 13 mW at the repetition rate of 67.5 MHz when the pump power is 140 mW. The output pulses are compressed with a pair of SF10 prisms and their durations are measured with SHG FROG, from which we obtained the pulse duration as short as 45 fs.

  6. Controlling the stoichiometry and doping of semiconductor materials

    Science.gov (United States)

    Albin, David; Burst, James; Metzger, Wyatt; Duenow, Joel; Farrell, Stuart; Colegrove, Eric

    2016-08-16

    Methods for treating a semiconductor material are provided. According to an aspect of the invention, the method includes annealing the semiconductor material in the presence of a compound that includes a first element and a second element. The first element provides an overpressure to achieve a desired stoichiometry of the semiconductor material, and the second element provides a dopant to the semiconductor material.

  7. Solid state laser employing diamond having color centers as a laser active material

    Energy Technology Data Exchange (ETDEWEB)

    Rand, S.C.; De Shazer, L.G.

    1987-01-20

    A laser is described comprising: resonant cavity means for supporting coherent radiation; a diamond containing color centers as a laser active material; means for exciting the color centers to emit coherent radiation; and optical path means for providing an exit path for the radiation from the resonant cavity means.

  8. Review of selective laser melting: Materials and applications

    Energy Technology Data Exchange (ETDEWEB)

    Yap, C. Y., E-mail: cyap001@e.ntu.edu.sg [Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Block N3.1 - B2c - 01, Singapore 639798 (Singapore); Energy Research Institute @ NTU, Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, Block S2 - B3a - 01, Singapore 639798 (Singapore); Chua, C. K., E-mail: mckchua@ntu.edu.sg; Liu, Z. H., E-mail: azhliu@ntu.edu.sg; Zhang, D. Q., E-mail: zhangdq@ntu.edu.sg; Loh, L. E., E-mail: leloh1@e.ntu.edu.sg; Sing, S. L., E-mail: sing0011@e.ntu.edu.sg [Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Block N3.1 - B2c - 01, Singapore 639798 (Singapore); Dong, Z. L., E-mail: zldong@ntu.edu.sg [School of Materials Science & Engineering, Nanyang Technological University, 50 Nanyang Avenue, Block N4.1, Singapore 639798 (Singapore)

    2015-12-15

    Selective Laser Melting (SLM) is a particular rapid prototyping, 3D printing, or Additive Manufacturing (AM) technique designed to use high power-density laser to melt and fuse metallic powders. A component is built by selectively melting and fusing powders within and between layers. The SLM technique is also commonly known as direct selective laser sintering, LaserCusing, and direct metal laser sintering, and this technique has been proven to produce near net-shape parts up to 99.9% relative density. This enables the process to build near full density functional parts and has viable economic benefits. Recent developments of fibre optics and high-power laser have also enabled SLM to process different metallic materials, such as copper, aluminium, and tungsten. Similarly, this has also opened up research opportunities in SLM of ceramic and composite materials. The review presents the SLM process and some of the common physical phenomena associated with this AM technology. It then focuses on the following areas: (a) applications of SLM materials and (b) mechanical properties of SLM parts achieved in research publications. The review is not meant to put a ceiling on the capabilities of the SLM process but to enable readers to have an overview on the material properties achieved by the SLM process so far. Trends in research of SLM are also elaborated in the last section.

  9. Review of selective laser melting: Materials and applications

    Science.gov (United States)

    Yap, C. Y.; Chua, C. K.; Dong, Z. L.; Liu, Z. H.; Zhang, D. Q.; Loh, L. E.; Sing, S. L.

    2015-12-01

    Selective Laser Melting (SLM) is a particular rapid prototyping, 3D printing, or Additive Manufacturing (AM) technique designed to use high power-density laser to melt and fuse metallic powders. A component is built by selectively melting and fusing powders within and between layers. The SLM technique is also commonly known as direct selective laser sintering, LaserCusing, and direct metal laser sintering, and this technique has been proven to produce near net-shape parts up to 99.9% relative density. This enables the process to build near full density functional parts and has viable economic benefits. Recent developments of fibre optics and high-power laser have also enabled SLM to process different metallic materials, such as copper, aluminium, and tungsten. Similarly, this has also opened up research opportunities in SLM of ceramic and composite materials. The review presents the SLM process and some of the common physical phenomena associated with this AM technology. It then focuses on the following areas: (a) applications of SLM materials and (b) mechanical properties of SLM parts achieved in research publications. The review is not meant to put a ceiling on the capabilities of the SLM process but to enable readers to have an overview on the material properties achieved by the SLM process so far. Trends in research of SLM are also elaborated in the last section.

  10. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials.

    Science.gov (United States)

    Kamarulzaman, Norlida; Kasim, Muhd Firdaus; Rusdi, Roshidah

    2015-12-01

    Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase. UV-visible spectroscopy showed that materials in the nanostructured state exhibit band gap widening with respect to their micron state while for the doped compounds exhibited band gap narrowing both in the nano and micron states with respect to the pure ZnO materials. The degree of band gap change was dependent on the doped elements and crystallite size. X-ray photoelectron spectroscopy (XPS) revealed that there were shifts in the valence bands. From both UV-visible and XPS spectroscopy, it was found that the mechanism for band gap narrowing was due to the shifting of the valance band maximum and conduction band minimum of the materials. The mechanisms were different for different samples depending on the type of dopant and dimensional length scales of the crystallites.

  11. Near-infrared emission character of Tm{sup 3+}-doped heavy metal tellurite glasses for optical amplifiers and 1.8 {mu}m infrared laser

    Energy Technology Data Exchange (ETDEWEB)

    Lin Hai [Faculty of Chemical Engineering and Materials, Dalian Institute of Light Industry, Dalian 116034 (China); Wang Xueying [Faculty of Chemical Engineering and Materials, Dalian Institute of Light Industry, Dalian 116034 (China); Lin Lin [Dalian Medical University, Dalian 116027 (China); Li Changmin [Faculty of Chemical Engineering and Materials, Dalian Institute of Light Industry, Dalian 116034 (China); Yang Dianlai [Faculty of Chemical Engineering and Materials, Dalian Institute of Light Industry, Dalian 116034 (China); Tanabe, Setsuhisa [Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan)

    2007-06-21

    Intense 1.8 {mu}m and efficient 1.47 {mu}m infrared emissions have been recorded in Tm{sup 3+}-doped alkali-barium-bismuth-tellurite (LKBBT) glasses with lower phonon energies under the excitation of a 792 nm diode laser. The maximum emission cross-sections for the 1.8 and 1.47 {mu}m emission bands are derived to be 6.643 x 10{sup -21} and 3.551 x 10{sup -21} cm{sup 2} and the peak values are obviously higher than those in Tm{sup 3+}-doped ZBLAN fluoride and TBSN tellurite glasses, respectively. In low concentration doping, the full-widths at half-maximum (FWHMs) of the two emission bands are 206 nm and 109 nm, respectively, and peak intensity ratio between them is about 2. When the doping concentration increases to 1 wt%, the peak intensity ratio exceeds 7 and the quantum efficiency of {sup 3}H{sub 4} level is only 64.6% due to the cross-relaxation process [{sup 3}H{sub 4}, {sup 3}H{sub 6}] {yields} [{sup 3}F{sub 4}, {sup 3}F{sub 4}], which benefits to achieve powerful 1.8 {mu}m emission. The efficient and broad 1.8 and 1.47 {mu}m infrared emission bands indicate that Tm{sup 3+}-doped LKBBT glasses are suitable materials in developing S- and U-band amplifiers and 1.8 {mu}m infrared laser.

  12. Lanthanide doped ceria thin films as possible counter electrode materials in electrochromic devices

    Energy Technology Data Exchange (ETDEWEB)

    Hartridge, A

    2000-09-01

    Crystalline solid solutions of lanthanide doped ceria have long been known for their high ionic conductivity and as such have found applications as oxygen sensors and in solid oxide fuel cells. With advances in preparative techniques over the years, thin films of ceria doped with zirconia and titania have been studied and found to possess the necessary criteria to meet the requirements of counter electrode materials in solid state electrochromic devices. Existing preparative techniques however, have failed to produce thin films of lanthanide doped ceria for study of their optical and electrochemical properties. This thesis therefore presents in the first chapter, existing knowledge of these materials, a novel preparation technique developed as part of the thesis to prepare these materials as crystalline aqueous dispersions suitable for the preparation of quality thin films and the subsequent characterisation of sols and gels of these materials compared to the same materials prepared by conventional techniques. High-resolution transmission electron microscopy has also been used to assess the homogeneity of these nanocrystals on a nanoscale for the first time. The second chapter then discusses the optical properties of solids and thin films in general before using the crystalline sols produced in chapter 1 to fabricate thin films of these materials for the first time. The optical properties of these materials is then discussed in detail and the results show the optical suitability of these thin films as counter electrodes in electrochromic devices. The final chapter then turns to the electrochemical insertion of lithium into these materials using cyclic voltammetry. All films studied enabled the reversible insertion of lithium with varying potentials and charge capacities without the loss of transmission of light common to other potential counter electrode materials. Certain compositions however, comprising ceria doped with Dy, Y, Nd and Pr, allowed enough lithium

  13. Fe-Doped Polycrystalline CeO2 as Terahertz Optical Material

    Institute of Scientific and Technical Information of China (English)

    WEN Qi-Ye; ZHANG Huai-Wu; YANG Qing-Hui; LI Sheng; XU De-Gang; YAO Jian-Quan

    2009-01-01

    @@ Fe-doped CeO2 is synthesized by ceramic method and the effects of Fe doping on the structure and properties are characterized by ordinary methods and terahertz-time domain spectrometer (THz-TDS) technique. Our results show that pure CeO2 only has a small dielectric constant ε of 4, while a small amount of Fe (0.9 at.%) doping into CeO2 promotes densification and induces a large ε of 23. From the THz spectroscopy, it is found that for undoped CeO2 both the power absorption and the index of re[faction increase with frequency, while for Fe-doped CeO2 we measure a remarkable transparency together with a flat index curve. The absorption coefficient of Fe-doped CeO2 at frequency ranging from 0.2 to 1.8 THz is less than 0.35 cm-1, implying that Fe-doped CeO2 is a potential THz optical material.

  14. Magnetism in alkali-metal-doped wurtzite semiconductor materials controlled by strain engineering

    Science.gov (United States)

    Guo, J. H.; Li, T. H.; Liu, L. Z.; Hu, F. R.

    2016-09-01

    The study of the magnetism and optical properties of semiconductor materials by defect engineering has attracted much attention because of their potential uses in spintronic and optoelectronic devices. In this paper, first-principle calculations discloses that cationic vacancy formation energy of the doped wurtzite materials can be sharply decreased due to alkali metal dopants and shows that their magnetic properties strongly depend on defect and doping concentration. This effect can be ascribed to the volume change induced by foreign elements doped into the host system and atomic population's difference. The symmetric deformation induced by biaxial strain can further regulate this behavior. Our results suggest that the formation of cationic vacancy can be tailored by strain engineering and dopants incorporation.

  15. Negative permittivity of ZnO thin films prepared from aluminum and gallium doped ceramics via pulsed-laser deposition

    DEFF Research Database (Denmark)

    Bodea, M. A.; Sbarcea, G.; Naik, G. V.

    2013-01-01

    Aluminum and gallium doped zinc oxide thin films with negative dielectric permittivity in the near infrared spectral range are grown by pulsed laser deposition. Composite ceramics comprising ZnO and secondary phase Al2O3 or Ga2O3 are employed as targets for laser ablation. Films deposited on glass...... from dense and small-grained ceramic targets show optical transmission larger than 70 % in the visible and reveal an onset of metallic reflectivity in the near infrared at 1100 nm and a crossover to a negative real part of the permittivity at approximately 1500 nm. In comparison to noble metals, doped...

  16. Multiwavelength Erbium-doped fiber laser employing nonlinear polarization rotation in a symmetric nonlinear optical loop mirror.

    Science.gov (United States)

    Tian, Jiajun; Yao, Yong; Sun, Yunxu; Yu, Xuelian; Chen, Deying

    2009-08-17

    A new multiwavelength Erbium-doped fiber laser is proposed and demonstrated. The intensity-dependent loss induced by nonlinear polarization rotation in a power-symmetric nonlinear optical loop mirror (NOLM) suppresses the mode competition of an Erbium-doped fiber and ensures stable multiwavelength operation at room temperature. The polarization state and its evolution conditions for stable multiwavelength operation in the ring laser cavity are discussed. The number and spectra region of output wavelength can be controlled by adjusting the work states of NOLM. (c) 2009 Optical Society of America

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

    OpenAIRE

    Tianxian Feng; Dong Mao; Xiaoqi Cui; Mingkun Li; Kun Song; Biqiang Jiang; Hua Lu; Wangmin Quan

    2016-01-01

    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...

  18. A Continuously Tunable Erbium-Doped Fibre Laser Using Tunable Fibre Bragg Gratings and Optical Circulator

    Science.gov (United States)

    Liu, Peng; Yan, Feng-Ping; Li, Jian; Wang, Lin; Ning, Ti-Gang; Gong, Tao-Rong; Jian, Shui-Sheng

    2008-12-01

    A continuously tunable erbium-doped fibre laser (TEDFL) based on tunable fibre Bragger grating (TFBG) and a three-port optical circulator (OC) is proposed and demonstrated. The OC acts as a 100%-reflective mirror. A strain-induced uniform fibre Bragger grating (FBG) which functions as a partial-reflecting mirror is implemented in the linear cavity. By applying axial strain onto the TFBG, a continuously tunable lasing output can be realized. The wavelength tuning range covers approximately 7.00nm in C band (from 1543.6161 to 1550.3307nm). The side mode suppression ratio (SMSR) is better than 50 dB, and the 3 dB bandwidth of the laser is less than 0.01 nm. Moreover, an array waveguide grating (AWG) is inserted into the cavity for wavelength preselecting, and a 50 km transmission experiment was performed using our TEDFL at a 10Gb/s modulation rate.

  19. Ion-exchanged tapered-waveguide laser in neodymium-doped BK7 glass.

    Science.gov (United States)

    Hettrick, S J; Mackenzie, J I; Harris, R D; Wilkinson, J S; Shepherd, D P; Tropper, A C

    2000-10-01

    We report what is to our knowledge the first operation of a planar dielectric tapered-waveguide laser. The waveguide laser is fabricated by potassium-ion exchange in Nd(3+) -doped BK7 glass and consists of a single-mode channel waveguide of a few micrometers' width followed by a linear taper up to a broad region with a width of ~180microm . A slope efficiency of 42% is found both in the tapers and in standard channel waveguides fabricated upon the same substrate, indicating that the tapers and the channels have similar internal losses; hence the low-loss nature of the tapered beam expansion. The output from either end of the tapered structure is found to be nearly diffraction limited.

  20. Erbium-doped CW and Q-switched fiber ring laser with fiber grating Michelson interferometer

    Institute of Scientific and Technical Information of China (English)

    Anting Wang(王安廷); Meishu Xing(邢美术); Hai Ming(明海); Jianping Xie(谢建平); Lixin Xu(许立新); Wencai Huang(黄文财); Liang Lü(吕亮); Xiyao Chen(陈曦曜); Feng Li(李锋); Yunxia Wu(吴云霞)

    2003-01-01

    The band-pass characteristic of fiber grating Michelson interferometer is analyzed, which acts as both band-pass filter and Q-switch. An erbium-doped fiber ring laser based on fiber grating Michelson interferometer is implemented for producing single longitudinal mode CW operation with 5 MHz spectral linewidth and up to 6 mW output power. In Q-switched operation, stable fiber laser output pulses with repetition rate of 800 Hz, pulse width of 0.6μs, average power of 1.8 mW and peak power of 3.4 W are demonstrated. The peak power and average power of the Q-switched pulses are varied with the repetition rate.