Search results for "Lithium"
showing 10 items of 680 documents
Kinetics of Photorefractive Light Scattering in Stoichiometric LiNbO3Single Crystals Grown from Melt Containing 58.6 Mole% of Li2O
2011
A study of kinetics of photo-refractive light scattering in ostensibly pure stoichiometric LiNbO3 (Li/Nb = 1) single crystal grown from melt containing 58.6 mole% Li2O excited by laser radiation of 0.53 μm is reported. Asymmetry of the distribution of scattered light intensity is revealed and found to be a linear function of the intensity of the exciting radiation in the 35–160 mW range. Due to heating of the crystal, at farther increase of the radiation intensity the distribution of scattered light contracts.
Conoscopic Studies of Optical Homogeneity of the LiNbO3:Mg Crystals
2012
An essential modification of the method to observe large-scale conoscopic images is proposed. Divergent beam of wide-aperture radiation is formed by a diffuser placed before entrance of a lithium niobate crystal. The optical homogeneity of LiNbO3:Mg crystals is studied in a wide range of the admixture concentrations (0.01 – 5.5 mol.%). An inhomogeneous distribution of the admixture is found to increase with the admixture concentration being accompanied by growth bands, micro-defects, such as micro-domains, domain boundaries, and block structures particularly in parts of higher concentration gradients at the boundaries of the growth bands.
Structural and Optical Homogeneity in Lithium Niobate Crystals of Low Photorefractivity
2015
Comprehensive studies by Raman and photo-induced light scattering complemented by laser conoscopy and electron spectroscopy of structural and optical homogeneity of nominally pure and modified lithium niobate crystals are reported.
Surface Periodic Poling in Lithium Niobate and Lithium Tantalate
2005
Periodic Poling of Lithium Niobate crystals (PPLN) by means of electric field has revealed the best technique for finely tailoring PPLN structures and parameters, which play a central role in many current researches in the field of nonlinear integrated optics. Besides the most studied technique of bulk poling, recently a novel technique where domain inversion occurs just in a surface layer using photoresist or silica masks has been devised and studied. This surface periodic poling (SPP) approach is best suited when light is confined in a thin surface guiding layer or stripe, as in the case of optical waveguide devices. Also, we found that SPP respect to bulk poling offers two orders of magn…
Silica masks for improved surface poling of lithium niobate
2005
Surface periodic poling of congruent lithium niobate was performed with the aid of photolithographically defined silica masks. The latter helped improving the control of duty cycle in the periodic domain poling, with 50:50 mark-to-space ratios. The role of silica was ascertained by numerically solving the Poisson equation.
Optical, thermal, electrical, damage, and phase-matching properties of lithium selenoindate
2011
LiInSe2, a biaxial nonlinear crystal transparent from 0.54 to 10 µm, is successfully grown in large sizes with good optical quality. We summarize all characteristics and physical properties of LiInSe2 essential for nonlinear frequency conversion.
Characterization of LiFePO4/C Composite Thin Films Using Electrochemical Impedance Spectroscopy
2012
The composite LiFePO4/C thin films were prepared on steel substrate by radio frequency (RF) magnetron sputtering. Electrochemical properties of the obtained thin films were investigated by cyclic voltammetry charge-discharge measurements and electrochemical impedance spectroscopy (EIS). The films annealed at 550 °C exhibited a couple of redox peaks at 3.45 V vs. Li/Li + characteristic for the electrochemical lithium insertion/extraction in LiFePO4. At low current rate such composite thin film showed a discharge capacity of over 110 mAh g -1 . The dependence of charge transfer resistance, double layer capacitance and lithium diffusion coefficients on applied electrode potential were calculat…
Multi-Module vs. Single-Module concept: Comparison of thermomechanical performances for the DEMO Water-Cooled Lithium Lead breeding blanket
2018
Abstract Within the framework of EUROfusion R&D activity an intense research campaign has been performed at the University of Palermo, in close cooperation with ENEA labs and KIT, in order to compare the thermomechanical performances of the Back Supporting Structure (BSS) of Multi-Module and Single-Module concepts of DEMO Water-Cooled Lithium Lead breeding blanket (WCLL). To this purpose, detailed 3D models of the DEMO WCLL right inboard and central outboard segments, including detailed BSS and simplified First Wall and structures according to the two concepts, have been set-up. The study has been performed considering the Normal Operation and Central Major Disruption steady state loading s…
Surface Periodic Domain Engineering in Congruent Lithium Tantalate Crystals
2006
First experiments with the novel electric field Surface Periodic Poling technique have been carried out on Lithium Tantalate. Optimal poling parameters gave 50:50 mark-to-space ratio in the micron scale with good uniformity and high repeatability.
Mesoscopic structural organization in fluorinated pyrrolidinium-based room temperature ionic liquids
2019
Abstract In this contribution the microscopic and mesoscopic structural organization in a series of fluorinated room temperature ionic liquids, based on N-methyl-N-alkylpyrrolidinium cations and on bis(perfluoroalkylsulfonyl)imide anions, is investigated, using a synergy of experimental (X-ray and neutron scattering) and computational (Molecular Dynamics) techniques. The proposed ionic liquids are of high interest as electrolyte media for lithium battery applications. Together with information on their good ion transport properties in conjunction with low viscosity, we also describe the existence of nm-scale spatial organization induced by the segregation of fluorous moieties into domains. …