Search results for " niobate"

showing 10 items of 101 documents

<title>Optical characteristics of doped lithium niobate single crystals</title>

2003

Studing of the Raman spectra was established that an optical parameters of oxygen-polyhedral ferroelectric single crystals can be improved by increasing the degree of structural ordering of the cation sublattice along the polar axis by doping them. In this case the impurity ions with the ionic radii close to the radii of the main cations (Li+ and Nb5+) and charges intermediate between those of main cations (1<Z<5) in the area of rather low concentrations were shown to exert an ordering effect on the cation sublattice of a congruent lithium niobate single crystals. Moreover the crystal resistance to laser radiation is also observed to grow. It was determined that the effect of diminishing ph…

Materials scienceIonic radiusCondensed matter physicsDopingLithium niobatePhysics::OpticsMineralogychemistry.chemical_elementFerroelectricityIonCrystalCondensed Matter::Materials Sciencesymbols.namesakechemistry.chemical_compoundchemistryCondensed Matter::SuperconductivitysymbolsCondensed Matter::Strongly Correlated ElectronsLithiumRaman spectroscopySPIE Proceedings
researchProduct

Kinetics of Photorefractive Light Scattering in LiNbO3:Cu and LiNbO3:Zn Single Crystals

2011

Results of studies of the kinetics of photorefractive light scattering (PRLS) in optically nonlinear congruent single crystals of lithium niobate (LiNbO3, Li/Nb = 0.946) containing multivalent cation admixtures of Cu [0.015 mass %] (“photorefractive”) and Zn [0.5 mass %] (“non-photorefractive”) are reported. The shape of the PRLS indicatrix is found to be different in case of Cu and Zn admixtures. However, the angular widening of the indicatrix in both cases reaches its stationary value faster at higher laser radiation intensities. The PRLS is found to depend on the site of the ingot from which the samples are cut – an evidence of non-uniform distribution of defects with localised electrons…

Materials scienceKineticsLithium niobateAnalytical chemistryPhotorefractive effectElectronCondensed Matter PhysicsLaserLight scatteringElectronic Optical and Magnetic Materialslaw.inventionchemistry.chemical_compoundCrystallographychemistryControl and Systems EngineeringlawMaterials ChemistryCeramics and CompositesElectrical and Electronic EngineeringIngotSingle crystalIntegrated Ferroelectrics
researchProduct

Dielectric properties of PMN+2%Li 2 O at low frequencies

2012

The reported study is focused on effects of the admixture of lithium (2% Li2O) on the low-frequency dielectric response in lead magnesium niobate ceramics over the 100 -300 K range of temperature. The obtained results reveal an essential thermal broadening of the e′(ν) spectra specific to relaxor ferroelectrics. Dispersion Δe′ = e′1Hz-e′1kHz and values of e′′(ν) in lead magnesium niobate ceramics containing Li are well described by the Cole-Cole equation at temperatures below the e′(T) maximum. Based on the analysis of the experimental data admixture of lithium is suggested to promote formation of domains in lead magnesium niobate ceramics (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Materials scienceLead magnesium niobateAnalytical chemistryMineralogychemistry.chemical_elementDielectricCondensed Matter PhysicsDielectric responseSpectral linechemistryvisual_artvisual_art.visual_art_mediumLithiumCeramicDispersion (chemistry)physica status solidi c
researchProduct

Growth of Lithium Niobate Single Crystals from Granulated Charge

2011

Comparative studies of different techniques and the synthesis of single-phase granulated mixtures of high density essentially improving technical and economical parameters of lithium niobate single crystal technology are reported. Efficiency of using granulated mixtures of high density in growing lithium niobate single crystals is discussed.

Materials scienceLithium niobateAnalytical chemistryMineralogyHigh densityCharge (physics)Condensed Matter PhysicsElectronic Optical and Magnetic Materialschemistry.chemical_compoundchemistryControl and Systems EngineeringMaterials ChemistryCeramics and CompositesElectrical and Electronic EngineeringSingle crystalIntegrated Ferroelectrics
researchProduct

Modelling of Cluster Formation in Optically Nonlinear Lithium Niobate Crystal

2011

Modelling of qualitative processes at formation of energetically stable clusters of oxygen octahedrons in the ferroelectric phase of lithium niobate (LiNbO3) crystal is considered with respect to composition. The structure of clusters arranged along the direction of crystallographic axis Y is shown to be the most ordered. The least ordered structures occur in clusters arranged along Z axis in the direction of which the values of ratio R = Li/Nb are most scattered.

Materials scienceLithium niobateCondensed Matter PhysicsFerroelectricityElectronic Optical and Magnetic MaterialsCrystalNonlinear systemchemistry.chemical_compoundCrystallographyLithium niobate crystalchemistryControl and Systems EngineeringPhase (matter)Materials ChemistryCeramics and CompositesCluster (physics)Electrical and Electronic EngineeringIntegrated Ferroelectrics
researchProduct

The Cation Sublattice Ordering in the Ferroelectric LiNbO3:Zn Single Crystals

2014

It has been revealed for the first time by Raman spectroscopy that in LiNbO3:Zn crystal with Zn2+ concentration range 0.03–0.94 mol.% the ordering of the main doping cations and vacant octahedrons along the polar axis is better than in the undoped crystal of congruent composition. Thus, the configuration of oxygen octahedrons is closer to ideal. The line widths of the Raman spectra in this concentration range are narrower than in congruent LiNbO3 crystals and closer to the line width in stoichiometric crystals with the best known cation ordering. As far as Zn2+ concentration is small, the growth technique changes very slightly compared to the growth of the pure LiNbO3 crystals.

Materials scienceLithium niobateDopingCondensed Matter PhysicsFerroelectricityElectronic Optical and Magnetic MaterialsCrystalchemistry.chemical_compoundCrystallographysymbols.namesakechemistrysymbolsPolarRaman spectroscopyStoichiometryLine (formation)Ferroelectrics
researchProduct

Quadratic nonlinear optical parameters of 7% MgO-doped LiNbO3 crystal

2016

International audience; Pure and 7% MgO-doped lithium niobate (LiNbO3) single crystals were grown by the Czochralski technique. The shift of optical absorption edge in 7% MgO-doped crystal in direction of shorter wavelength compared to undoped crystal was observed. The second harmonic generation measurements of 7% MgO-doped LiNbO3 crystal were performed at room temperature by means of the rotational Maker fringe technique using Nd:YAG laser generating at 1064 nm in picoseconds regime. Experimentally obtained value of nonlinear optical coefficient d33 for 7% MgO-doped LiNbO3 was found to be less than for undoped crystal but higher than for 5% MgO-doped. I-type phase-matched second harmonic g…

Materials scienceLithium niobatePhysics::Optics02 engineering and technologyPhase matching01 natural scienceslaw.invention010309 opticsInorganic ChemistryCrystalchemistry.chemical_compoundCondensed Matter::Materials ScienceOpticslawCondensed Matter::Superconductivity0103 physical sciencesPhysics::Atomic and Molecular Clusters[CHIM]Chemical SciencesElectrical and Electronic EngineeringPhysical and Theoretical ChemistrySpectroscopybusiness.industryOrganic ChemistryDopingSecond-harmonic generationSecond harmonic generationLithium niobate021001 nanoscience & nanotechnologyLaserAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsWavelengthchemistryAbsorption edgePicosecondOptoelectronicsCondensed Matter::Strongly Correlated Electronsmaker fringes0210 nano-technologybusiness
researchProduct

MICRO- AND NANO-STRUCTURES OF NOMINALLY PURE STOICHIOMETRIC LITHIUM NIOBATE SINGLE CRYSTAL IN RAMAN SPECTRA

2009

ABSTRACT The authors show that bandwidths in Raman spectra of ferroelectric photo-refractive single crystals may depend on wavelength of laser radiation exciting the spectrum. Raman bands of lithium niobate single crystals are broader if the spectrum is excited by laser radiation in visible as compared with the spectrum excited by infrared laser radiation. Local microscopic structural heterogeneities of altered index of refraction are shown to appear in parts of the crystal under laser irradiation. Under visible radiation the structural heterogeneities provide additional contribution to broadening of Raman bands. Similar microscopic heterogeneities are practically absent at laser irradiatio…

Materials scienceLithium niobatePhysics::OpticsMolecular physicslaw.inventionCrystalchemistry.chemical_compoundsymbols.namesakeOpticslawMaterials ChemistryPhysics::Atomic PhysicsIrradiationElectrical and Electronic Engineeringbusiness.industryFar-infrared laserCondensed Matter PhysicsLaserFerroelectricityElectronic Optical and Magnetic MaterialschemistryControl and Systems EngineeringCeramics and CompositessymbolsbusinessRaman spectroscopySingle crystalIntegrated Ferroelectrics
researchProduct

Near-field scanning optical microscopy to study nanometric structural details of LiNbO3 Zn-diffused channel waveguides

2008

A near-field scanning optical microscope (NSOM) is used to perform structural and optical characterization of the surface layer after Zn diffusion in a channel waveguide fabricated on lithium niobate. A theoretical approach has been developed in order to extract refractive index contrast from NSOM optical transmission measurements (illumination configuration). As a result, different solid phases present on the sample surface can be identified, such as ZnO and ZnNb2O6. They appear like submicrometric crystallites aligned along the domain wall direction, whose origin can be ascribed to some strain relaxation mechanism during the annealing process after Zn diffusion. Jose.Canet-Ferrer@uv.es

Materials scienceLithium niobateRefractive indexGeneral Physics and AstronomyWaveguide (optics)law.inventionAnnealingchemistry.chemical_compoundAnnealing ; Crystallites ; Lithium compounds ; Nanostructured materials ; Near-field scanning optical microscopy ; Optical waveguides ; Refractive index ; StoichiometryOpticsOptical microscopelaw:FÍSICA [UNESCO]Refractive index contrastSurface layerNear-field scanning optical microscopyÓpticabusiness.industryUNESCO::FÍSICACrystallitesFísicaLithium compoundsNanostructured materialsStoichiometryOptical waveguideschemistryNear-field scanning optical microscopeCrystallitebusinessRefractive index
researchProduct

Continuous-wave backward frequency doubling in periodically poled lithium niobate

2010

We report on backward second-harmonic-generation in bulk periodically poled congruent lithium niobate with a 3.2 microns period. A tunable continuous-wave Ti:sapphire laser allowed us exciting two resonant quasi-phase-matching orders in the backward configuration. The resonances were also resolved by temperature tuning and interpolated with standard theory to extract relevant information on the sample.

Materials sciencePhysics and Astronomy (miscellaneous)business.industryNonlinear optics Parametric processes Backward frequency doublingLithium niobatePhysics::OpticsFOS: Physical sciencesLaserlaw.inventionchemistry.chemical_compoundOpticschemistrylawSapphireContinuous waveStandard theorybusinessRelevant informationPhysics - OpticsOptics (physics.optics)
researchProduct