bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of Electro-Optic Bi12SiO20 Thin Films Grown by Electron Cyclotron Resonance Plasma Sputtering
Authors: Nomura Koji , Ogawa Hisahito 
Published: March 2011

AbstractBi12SiO20 thin films have been prepared on glass and (0001) sapphire substrates by ECR plasma sputtering with a Bi and Si multitarget system. Polycrystalline thin films of δ-phase Bi12SiO20 have been obtained without any substrate heating. These films can be transformed into γ-phase Bi12SiO20 by heat treatment above 400°C in air and show a large photoconductivity in the range of 380–460 nm. Epitaxial thin films of γ-phase Bi12SiO20 have been obtained on (0001) sapphire substrates at the substrate temperature of 600δ during the sputtering process. Excellent quadratic electrooptic effects for these epitaxial thin films are successfully observed for the first time, and a spatial light modulator using this γ-phase Bi12SiO20 thin film has also been demonstrated. The details of the preparation, structure and some electrical and electrooptic properties of the Bi12SiO20 thin films are described.
Microstructural Evolution of Sol-Gel Derived PZT Thin Films
Authors: Hsueh Cheng-Chen , Mecartney Martha L. 
Published: March 2011

AbstractTransmission electron microscopy (TEM) was used to investigate the microstructural evolution of sol-gel derived ferroelectric PZT films. Aggregates of perovskite crystals nucleated and grew out of a pyrochlore matrix at 550°C. A dense, single-phase perovskite PZT film was obtained by fast firing the film at 650°C for 30 minutes. The grain size of this film was approximately 0.2-0.4 μm. Hot-stage TEM observed disappearance of ferroelectric domains as the temperature approaching 325°C.
Substrate Effects in In-Situ Growth of Perovskites by Pulsed Laser Deposition
Authors: Etzold K. F. , Roy R. A. , Saenger K. L. 
Published: March 2011

AbstractIn this study we report on in-situ growth of lead zirconate titanate (PbZr1-xTixO3, PZT) and strontium titanate (SrTiO3, STO) films by pulsed laser deposition at 248 nm. Films were deposited in an oxygen background at elevated temperatures on a variety of substrates including MgO(l00), Pt(100)/MgO(100), Pt(111)/MgO(111), Pt(110)/MgO(110), Pt(111)/SiO2/Si, and Pt(111)/glass.Deposited films were characterized by Rutherford Backscattering Spectroscopy (RBS), x-ray diffraction (XRD), and electrical (dielectric constant and leakage) measurements. A strong substrate dependence was found for both the fraction of pyrochlore (Pb2Zr2-xTixO7) phase in the PZT films, and the STO film dielectric constants. The origin of the substrate dependence is discussed with regard to nucleation and interface layer cffects, and the chemistry of the relevant materials.
Dielectric Constant and Hysteresis Loop Remanent Polarization from 100 Hz to 2 MHz for Thin Ferroelectric Films
Authors: Bennett K. W. , Brody P. S. , Rod B. J. , Cook L. P. , Schenck P. K. , Dey S. 
Published: March 2011

AbstractA modification of the standard Sawyer-Tower circuit method of displaying ferroelectric hysteresis allowed the technique to be extended to sinusoidal switching frequencies of 2 MHz. Using this method, probe station measurements of switched remanent polarization were made for two films: excimer-laser-deposited lead zirconate titanate (PZT) and sol-gel PZT. Switched remanent polarization and dielectric constant were measured as a function of frequency between 100 Hz and 2 MHz and as a function of elapsed switching cycles at the 1-MHz rate. Both films showed decreasing switched remanent polarization and dielectric constant with increasing frequencies. This effect is attributed to limitations in domain wall velocity.
Optical Characterization of Potassium Niobate Thin Film Planar Waveguides
Authors: Graettinger Thomas M. , Kingon A. I. 
Published: March 2011

AbstractInitial results of the waveguiding properties of KNbO3 thin films are presented. The refractive indices of epitaxial films deposited on single crystal magnesium oxide substrates have been measured. Additionally, these films have been used as the basis for modelling a potassium niobate thin film phase modulator. Results of the model are compared with existing technology.
IR Transmission Chalcogenide Glass Fibers
Authors: Yamagishi T. , Inagawa I. , Nishii J. 
Published: March 2011

ABSTRACTSeveral chalcogenide glass fibers with Teflon cladding and glass cladding were prepared for infrared optical application. A minimum transmission loss, at C02 laser wavelength, of 0.9 dB/m was attained in SeTel glass fiber. The CO and CO2 laser power transmission characteristics of fibers were investigated. Selenide and telluride glass fibers yielded damage thresholds lower than sulfide glass fiber because of their large temperature dependence of refractive index and transmission loss. Deliveries of 80 W of CO laser light in AsS glass fiber, and 10 W of CO2 laser light in GeSeTe glass fiber, were attained. An AsS fiber bundle of 8400 cores was prepared, which could deliver a clear thermal image below 100 °C. Prepared fibers were also found useful for low temperature monitoring and gas sensing in narrow or restricted spaces.
Plasma-Enhanced Chemical Vapor Deposition of ZrF4-Based Fluoride Glass Film and Oxygen Doping Effects on Glass Forming Ability
Authors: Fujiura K. , Nishida Y. , Kobayashi K. , Takahashi S. 
Published: March 2011

ABSTRACTZrF4-based binary glass film is synthesized for the first time by plasma-enhanced chemical vapor deposition (PCVD). The optical transmission spectrum is measured and the effects of oxygen doping on the glass forming ability are clarified. No absorption band caused by OH or other impurities is observed in the near IR region. Weak absorption bands attributed to defect centers are observed in the UV to visible region. The glass forming region in the ZrF4-BaF2 system is significantly improved by oxygen doping. Oxygen ions are distributed homogeneously in the fluoride glass film by PCVD and improve its stability against crystallization.
Optical Properties of ZrF4 Thin Film Formed by Vapour Phase Deposition
Authors: Kono Takao , Morita Shinzo , Goto Toshio , Nishiwaki Akira 
Published: March 2011

ABSTRACTZirconium fluoride (ZrF4 ) thin films were formed by plasma CVD and evaporation for thin-film optical wave guide. In the case of plasma CVD, ZrF4 compound was actually observed to be synthesized from the vapour of Zr and CF4 gas according to. ESCA measurement, even if the film contained impurities. As for evaporation, transparent and amorphous film was obtained and optical transmission loss was measured by scattering detection method, and the loss was calculated to be 9.5 dB/cm. But when only ZrF4 was deposited, thin film was tarnished to be white because of adsorption of moisture. Therefore, simultaneous evaporation of ZrF4 and BaF2 was performed and the charastaristic was stabilized.
Hydroxyl Formation in Silica Tubes and Layers due to Oxy–Hydrogen Flames
Authors: Kirchhof J. , Braun G. 
Published: March 2011

ABSTRACTA novel kind of hydroxyl formation during the processing of quartz glass tubes with oxy-hydrogen burners was found and studied in detail by high-resolution laser spectroscopy. The formation mechanism involving hydrogen penetration from the flame and following reactions is discussed.
Concentration and Hydroxyl Impurity Quenching of the 4I13/2–4I15/2 Luminescence in Er3+ Doped Sodium Silicate Glasses
Authors: Bruce Allan J. , Reed W. A. , Neeves A. E. , Copeland L. R. , Grodkiewicz W. H. , Lidgard A. 
Published: March 2011

ABSTRACTLifetimes for the 4I13/2–4I15/2 transition of excited Er3+ ions in sodium di-silicate glasses have been measured as a function of Er3+ concentration and glass melting conditions. Lifetimes in excess of 20 ms have been measured for Er3+ levels up to 1021 ions/cm3. For Er3+ levels above 5 × 1020 ions/cm3 high lifetimes are only observed in glasses with low −OH impurity levels. The results are consistent with a quenching mechanism incorporating energy transfer between Er3+ ions followed by non-radiative decay via Er3+ ions coupled to the −OH impurity phonons.
Excited-State-Absorption Cross Sections and Amplifier Modeling in the 1300-nm Region for Nd-Doped Glasses
Authors: Zemon S. , Pedersen B. , Lambert G. , Miniscalco W. J. , Hall B. T. , Folweiler R. C. , Thompson B. A. , Andrews L. J. 
Published: March 2011

ABSTRACTThe performance of Nd3+-doped fiber amplifiers is limited by strong excited state absorption (ESA) of the signal, even for fluorozirconate glasses where ESA prevents the important region below 1320 nm from being used. To quantify this and explore alternative host materials, ESA and stimulated-emission cross sections have been measured for a representative group of glass compositions. These parameters have been used in an accurate, fiber-amplifier model to provide the first quantitative comparisons of performance for Nd3+-doped glasses in the 1300-nm band as a function of host. A high-fluorine fluorophosphate is predicted to extend the short-wavelength boundary of the gain spectrum to 1295 nm but only at reduced gain levels and at the cost of having lower gains at longer wavelengths than fluorozirconates. A substantial increase in small-signal gain is predicted if the amplified spontaneous emission for the 1050-nm band is suppressed.
Luminescent Properties of Rare Earth Doped AlF3-Based Glasses
Authors: Copeland L. R. , Reed W. A. , Shahriari M. R. , Iqbal T. , Hajcak P. , Sigel G. H. 
Published: March 2011

ABSTRACTRare earth ions can easily be incorporated into fluoride glasses in moderate to large concentrations and, due to their low phonon energy, these glasses appear to have many advantages over oxide glasses as hosts for rare earth ions used in optical amplifiers and lasers. We have therefore investigated the optical properties of Pr3+, Pr3+/Yb3+ and Pr3+/Yb3+/Lu3+ doped bulk AIF3-based glass samples as a function of rare earth ion concentration. We find that the addition of 2 wt% of Yb increases the fluorescence of Pr3+ at 1.32 μm by a factor of 35 when excited with 488 nm radiation. The fluorescence intensity and excited state lifetimes are found to be comparable to those measured for Pr in a ZBLAN host. Since it has also been demonstrated that optical fibers drawn from AIF3-based glasses exhibit relatively low loss (< 0.05 dB/m) and posses superior chemical durability compared to other fluotide glasses, it is possible that AIF3 glasses may become the fluoride glass of choice for practical fiber laser and amplifier applications.
Efficient Erbium-Doped Fiber Amplifiers Pumped in the 800-nm Band
Authors: Pedersen B. , Zemon S. , Miniscalco W. J. 
Published: March 2011

ABSTRACTA comprehensive theoretical investigation of the 800-nm pump band for erbium-doped fiber amplifiers is presented. Both a silica and a fluorophosphate host are examined. To obtain the same amplification, the fluorophosphate requires 2–3 dB less pump power.
Optical Properties of Soot Remelted Silica Irradiated with Excimer Lasers
Authors: Matsumoto Yasutaka , Kuzuu Nobu , Murahara Masataka 
Published: March 2011

ABSTRACTCharacteristics of ArF laser induced luminescence, and absorption bands in soot remelted silica, before and after annealing in various atmospheres, were investigated. A soot remelted silica containing no OH has an absorption band at 5.1 eV which can be annealed out with H2, but an absorption band at 5.8 eV is induced by subsequent the ArF laser irradiation. In a soot remelted silica containing 50 ppm of OH, an emission band at 1.9 eV was induced by the ArF laser irradiation. The 1.9 eV band can be annealed out with He and H2, but, by annealing in H2, the 5.8 eV absorption band was induced by the ArF laser irradiation as in the case of the silica containing no OH.
Sol-Gel and RF Sputtering Thin Film Coatings for Fiber Optic Sensor Applications
Authors: Shahriari M. R. , Ding J. Y. , Wang C. M. , Lin C. H. , Sigel G. H. 
Published: March 2011

ABSTRACTThin film coating techniques appear to have many advantages over other techniques for immobilization and incorporation of chemical indicators to optical waveguides in developing dye based fiber optic chemical sensors. We have fabricated thin films of composites by using sol-gel and RF sputtering techniques. Different organic and inorganic indicators were immobilized in these films and incorporated into optical waveguides for sensor applications. A fiber optic pH sensor has been developed by introducing pH indicators into a silica matrix and coated as a thin film onto a porous glass fiber by a sol-gel technique. Also, a hydrogen gas fiber optic sensor has been developed by using a RF sputtered WO3/Pd coated porous optical fiber.
Active Waveguides in LiNbO3
Authors: Micheli M. P. De 
Published: March 2011

ABSTRACTIn Integrated Optics (10), LiNbO3 is a well known material, widely used to realize very efficient electro-optic integrated devices for telecommunications such as phase modulators, intensity modulators and directional couplers. But, with the availability of good quality rare earth doped material and the perfecting of a new waveguide fabrication technique, Proton Exchange (PE), a completely different set of active devices are now possible. The common factor of these devices is that they take advantage of the high optical power resistance of the PE waveguides, of the amplification due to the rare earths, and, of the electro-optic/nonlinear properties of the crystal. In this paper we shall present such devices we have demonstrated in collaboration with the Central Research Laboratory of Thomson CSF and the Ecole Nationale Supérieure de Physique de Marseille.:-an optically pumped CW amplifier in Nd:MgO:LiNbO3 offering up to 8 dB small signal gain at δ = 1.085μm-an optically pumped CW laser in Nd:MgO:LiNbO3 emitting 14 mW at X = 1.085μm with a slope efficiency of 34% and a threshold of 2.7 mW-an FM Mode-locked waveguide laser in Nd:MgO:LiNbO3 realized by electro-optically driving the laser at the cavity round-trip frequency emitting 8 ps pulses of 250 mW peak power with a 6.2 GHz repetition rate-a self doubled waveguide laser in Nd:MgO:LiNbO3 emitting some hundreds of μW in the blue (SHG of the pump and mixing the pump with the laser frequency) and the green (SHG of the laser wavelength).
Radiation-Hardened Optical Fibers for High Dosage Space Applications
Authors: Miller A. E. , Yan M. F. , Watson H. A. , Nelson K. T. 
Published: March 2011

ABSTRACTHydrogen doping of optical fibers has been examined as an approach to increase the radiation hardness of optical fibers for high dosage (107 rad) space applications. A systematic study has been performed on 4 types of optical fibers designed to operate at 1.31 and 1.55 μm and doped with up to 8200 ppm H2. For low dosages, the most significant reductions m radiation-induced losses were obtained with low H2 concentrations (<10 ppm). Spectral loss measurements for hydrogen-doped fibers containing GeO2 show a radiation-induced loss peak at 1.45 μm and a broad absorption band around 0.6–0.8 μm. These bands are not observed in the pure silica-core fibers.Fibers were fabricated to permanently trap 2.7 ppm H2 and the radiation-induced losses in these fibers are 35 to 85% that of the untreated fibers. Experimental data are used to delineate the γ-T-α operating limits which define the maximum gamma radiation (γ) dosages at different temperatures (T) while still meeting a requirement of α<150 dB/km. Among the four fiber types, hydrogen-doped silicacore fibers show the widest operating range and smallest radiation-induced loss for space applications. However, hydrogen-doped fibers with moderately high GeO2-doped core offer the best tradeoff between the bending and radiation-induced losses.
Dopants in LiNbO3: Lattice Site Location, Ion Implantation and Epitaxial Regrowth
Authors: Rebouta L. , Soares J. C. , Silva M. F. Da , Sanz-Garcia J. A. , Dieguez E. , Agullo-Lopez F. 
Published: March 2011

ABSTRACTIon-beam/channeling data for the lattice location of Ti, Hf, Er and Nd in LiNbO3 and LiNbO3: Mg are presented. These impurities are relevant in relation to waveguide and integrated optics devices. It is shown that co-doping with Mg markedly influences the lattice location observed in LiNbO3. The amorphization and recrystalization process following Hf implantation and annealing are also discussed.
Excimer Laser Induced 5.8 eV Absorption and 1.9 eV Emission Bands in Fused Silicas
Authors: Kuzuu Nobu , Matsumoto Yasutaka , Murahara Masataka 
Published: March 2011

ABSTRACTCharacteristics of ArF excimer laser induced 1.9 eV emission and 5.8 eV absorption bands in type III and soot remelted silicas were investigated. In a type III silica synthesized in a reducing condition, an absorption band at 5.8 eV band is induced. The creation of this band can be prevented by annealing in an atmosphere of He. In the soot remelted silicas with and without OH, the creation of the 5.8 eV band is strongly promoted by annealing in H2. An emission band at 1.9 eV is induced in a type III fused silica synthesized in an oxydizing condition and soot remelted silica containing OH. When annealing in He, creation of the 1.9 eV band is strongly promoted in the former but suppressed in the latter sample. This difference is derived from the difference of higher order structures between the type III and the soot remelted silicas.
Realization of SiO2-B2O3-TiO2 Waveguides and Reflectors on Si Substrates
Authors: Schneider Hartmut W. 
Published: March 2011

ABSTRACTTiO2-B2O3 doped silica single-mode waveguide arrays on silicon substrates were fabricated by flame hydrolysis soot deposition, glass consolidation and etching. CHF3 reactive ion etching is suitable for more than 15 μm deep vertical gap and reflector preparation. Minimum waveguide propagation loss values of (0.21±0.01) dB/cm were measured on 50 mm single-mode samples. Spectral measurements proved the absence OH absorption in the 850 to 1600 nm range and indicate scattering as the most important loss effect.
Photolithographic Imaging of Planar Optical Waveguides and Integrated Optic Devices onto Porous Silicate Glasses and Silica Sol-Gels
Authors: Mendoza Edgar A. , Gafney Harry D. 
Published: March 2011

ABSTRACTThe success of photonic switching depends on the development of materials capable of processing light signals without the interweaving conversion to electronic signals. The photodeposition of metal oxides onto porous Vycor glass and silica glass sol-gels produce changes in the index of refraction of the glass of the order of 0.1 to 0.001. Nonlinearities in transmission and refractive index allow the deposition of 1.0-10.0 μm width planar waveguides with attenuations of 0.6 dB/cm. This technique is being evaluated for the optical performance of couplers, dividers, and interferometers. Also 3-dimmensional interactive planar waveguide structures are being fabricated in silica sol-gel thin-films.
Photoinduced Second Harmonic Generation in Optical Fibers: Materials and Mechanisms
Authors: Krol D. M. , Simpson J. R. , DiGiovanni D. J. , Atkins R. M. , Lemaire P. J. , Nelson K. T. 
Published: March 2011

ABSTRACTPermanent X(2) gratings can be written in doped silica fibers by coherent irradiation with light at ω and 2ω. The X(2) gratings give rise to phase-matched second harmonic generation (SHG), i.e. subsequent irradiation of the prepared fiber with light at ω results in an output at 2ω. The efficiency with which the gratings can be written depends on the nature and concentration of defect states induced by dopants in the, glass. We present results for fibers doped with Ge and rare earth ions and discuss the implications of our results for the various mechanisms that have been proposed to explain photoinduced SHG in fibers.
Chemical Kinetics Applied to the Fatigue of Silica Fibers in Sodium Hydroxide Solutions
Authors: Inniss Daryl , Brownlow Darryl L. , Kurkjian Charles R. , Borges Lourdes R. 
Published: March 2011

ABSTRACTChemical kinetics is applied to the fatigue (stress assisted corrosion) of silica fibers in NaOH solutions. The thermodynamic parameters are determined and compared to measurements in water; the zero stress activation energy is the same for the two systems (∼25kcal/mol), but the activation volume in aqueous NaOH solutions is smaller (∼11cm3/mol) than that in water (∼27cm3/mol). The accelerated fatigue rate is dominated by a three decade decrease in the pre-exponential factor; it is shown that this decrease can be attributed to an increase in the entropy of the system.
Microstructural Properties of Fly Ashes from Oklahoma and Wyoming Coals and their Blends
Authors: Laguros Joakim G. , Gollahali S. R. 
Published: March 2011

ABSTRACTBlending of different types of coals is an economical method of utilizing locally available lower quality coals. Four blends of Wyoming/Oklahoma coal were prepared (100:0, 90:10, 75:25, 0:100) and burned in a laboratory furnace in a diffusion flame of a mixture of propane and nitrogen in air. Flame temperatures ranged from 1419 K for Oklahoma to 1626 K for Wyoming coal. The higher temperatures indicate better boiler utility, more oxidation, less free carbon, more and better quality fly ash. These observations conform well with the SEM evaluations which indicated that as the amount of Wyoming coal increased, the matrix contained densely populated glassy spherical particles. The SEM data on cured paste samples indicated that the Wyoming fly ash showed a better tendency to crystal (presumably ettringite) formation, followed by the blends of 90% Wyoming-10% Oklahoma and 75% Wyoming-25% Oklahoma. The least amount of crystal formation was observed in the fly ash of 100% Oklahoma coal. These effects are extremely pronounced in the early curing stages.
Polyphosphate Chain Stability in Magnesia-Polyphosphate Cements
Authors: Dimotakis E. D. , Klemperer W. G. , Young J. F. 
Published: March 2011

ABSTRACTPolyphosphates of the general formula NanH2PnO3n+1·H2O, n = 6, 15, 70, where n is the average degree of polymerization, have been synthesized and characterized by 31P NMR and HPLC. Aqueous solutions of these polyphosphates react at room temperature with magnesia to form cement pastes that harden to amorphous materials. The compressive strengths and porosities obtained are similar to those of MgO-(NH4)H2P3O10-H2O cements. Although polyphosphate chain length does not have a significant effect on the strength of the cement, 31P MAS-NMR spectroscopy showed that the degree of polyphosphate chain degradation decreases as the average degree of polymerization, n, increases.
DSP with Rutile Substituting for Microsilica
Authors: Aldridge Laurence. P. , Campbell Ross J. , Cassidy David J. 
Published: March 2011

ABSTRACTDSP is made from heavily superplasticized cement combined with microsilica and relatively small amounts of water. In this paper it is shown that substitution of fine-grained rutile for microsilica results in a workable DSP mix.A comparison of the TGAs, XRDs, SEMs, mercury intrusion porosimetry, and compressive strengths between the two DSP preparations is reported. The results indicate that the DSP made with rutile has very similar properties to DSP made with microsilica.
Microwave Characterization of Cement Hydration
Authors: Moukwa M. , Brodwin M. , Christo S. , Chang J. , Shah S.P. 
Published: March 2011

ABSTRACTConductivity and permittivity of cements were measured during the first 24 h hydration period at 10.0 GHz using front surface reflection methods. Data trends closely followed the hypothesis that the microwave results responded to the transition from free to bound water as hydration proceeded. The results were also compared to measured hydration curves and changes in the slope of the data versus time correlated well with characteristics regions of the hydration curve. The results establish the usefulness of microwave characterization for the study of chemistry and structure during the hydration period and may lead to a non destructive test method for cementitious materials during the early curing period.