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Optical Crystal (optical + crystal)

Distribution by Scientific Domains
Physics and Astronomy100%

Kinds of Optical Crystal

  • nonlinear optical crystal
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    Selected Abstracts

    Growth and properties of an organometallic nonlinear optical crystal: bis(isothiocyanato)-bis(4-methylpyridine)zinc(II) (Zn(SCN)2(C6H7N)2)

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2006
    L. Y. Zhu
    Abstract Bis(isothiocyanato)-bis(4-methylpyridine)zinc(II)(Zn(SCN)2(C6H7N)2), (abbreviated as ZBNC) single crystals of optical quality have been grown from acetone solution by the slow temperature-lowering method. Its solubilities at different temperatures in acetone were measured. The X-ray powder diffraction (XRPD) spectroscopy of ZBNC crystal was performed at room temperature. The second harmonic generation (SHG) efficiency was determined by powder technique of Kurtz and Perry using Nd:YAG laser, which is equivalent to KDP crystal. The thermal decomposition process was characterized by thermal gravity and differential thermal analysis (TG\DTA). The specific heat of the crystal is 1440.67 J/mol·K at 325 K. The IR spectrum was recorded in the 500,3500 cm,1 region, using KBr pellets on a Nicolet 170sx FT-IR spectrometer. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Trigonal Na3Li(MoO4)2·6H2O , a new many-phonon SRS molybdate crystal offering numerous nonlinear-laser interactions: several cascaded lasing (,(3),,(2)) effects and more than sesqui-octave Stokes and anti-Stokes comb generation under one-micron picosecond pumping

    LASER PHYSICS LETTERS, Issue 5 2009
    A.A. Kaminskii
    Abstract Trigonal Na3Li(MoO4)2·6H2O was found to be an attractive, simultaneously ,(2) - and ,(3) -active nonlinear optical crystal. We investigated its basic optical properties and observed several nonlinear effects, namely many-phonon SRS, almost twooctave Stokes and anti-Stokes lasing combs, SHG, THG, and efficient cascaded (,(3),,(2))-generation, as well as SRS arising from nonlinear interaction of two different ,(3) -active vibrations. All recorded nonlinear-lasing components were identified and attributed to SRS-promoting vibration modes. A short review of nonlinear-laser molybdates is given. (© 2009 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

    Tetragonal Ba2MgGe2O7 , a novel multifunctional optical crystal with numerous manifestations of nonlinear-laser effects: almost sesqui-octave Stokes and anti-Stokes combs and cascaded ,(3),,(2) lasing with involved second and third harmonic generation

    LASER PHYSICS LETTERS, Issue 12 2008
    A.A. Kaminskii
    Abstract Melilite-type Ba2MgGe2O7 was found to be an attractive, simultaneously ,(2) - and ,(3) -active nonlinear optical crystal. Under one-micron picosecond pumping we observed several manifestations of nonlinear interactions, namely almost sesqui-octave Stokes and anti-Stokes lasing combs, collinear and "Cherenkov"-type SHG, THG, SFG, and cascaded selfconversion ,(3),,(2) generation in the visible and UV range. All recorded lasing components were identified and attributed to a single SRS-promoting vibration mode ,SRS = 771.5 cm,1. A short review of melilite-type compounds is given. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

    Effect of different metal ions on structural, thermal, spectroscopic and optical properties of ATCC and ATMC single crystals

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2007
    R. Perumal
    Abstract A novel metal-organic coordination complex nonlinear optical crystals, tri-allylthiourea cadmium chloride [(CdCl2(AT)3] and tri-allylthiourea mercury chloride [(HgCl2(AT)3] abbreviated as ATCC, ATMC (AT is Allylthiourea i.e.,CH2=CHCH2NHCSNH2) has been synthesized and grown as single crystals. It was synthesized in deionised water and further recrystallized to improve its purity. Single crystals of the allylthiourea co-ordination complex nonlinear optical crystals tri allylthiourea cadmium chloride (ATCC) with dimensions of 14x14x10 mm3 and tri allylthiourea mercury chloride (ATMC) with dimensions of 15x15x12 mm3 were grown successfully from aqueous solution by solvent evaporation as well as by temperature lowering method. It exhibits powder SHG efficiencies higher than that of a well known organic NLO crystal Urea. The solubility of the as grown crystals was estimated from the aqueous solution and the effect of different metal ions on the grown crystals, structural, thermal, spectral and optical properties were analyzed. XRD studies the reveals the same structure of both materials. Influence of the different central metal (Cd and Hg) atoms, changing the thermal properties of the materials when NLO complexes formed with the common ligand allylthiourea. The metal co-ordination was confirmed form the spectroscopic analysis. From the UV transmittance studies, red shift was from the transparency cut-off wavelengths. The value is 285nm for ATCC is and is 335nm ATMC, Non-linear an optical study confirms the suitabilities of the as grown crystals for the non linear optical applications. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Equilibrium and growth shapes of crystals: how do they differ and why should we care?

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 4-5 2005
    Robert F. SekerkaArticle first published online: 15 MAR 200
    Abstract Since the death of Prof. Dr. Jan Czochralski nearly 50 years ago, crystals grown by the Czochralski method have increased remarkably in size and perfection, resulting today in the industrial production of silicon crystals about 30 cm in diameter and two meters in length. The Czochralski method is of great technological and economic importance for semiconductors and optical crystals. Over this same time period, there have been equally dramatic improvements in our theoretical understanding of crystal growth morphology. Today we can compute complex crystal growth shapes from robust models that reproduce most of the features and phenomena observed experimentally. We should care about this because it is likely to result in the development of powerful and economical design tools to enable future progress. Crystal growth morphology results from an interplay of crystallographic anisotropy and growth kinetics by means of interfacial processes and long-range transport. The equilibrium shape of a crystal results from minimizing its anisotropic surface free energy under the constraint of constant volume; it is given by the classical Wulff construction but can also be represented by an analytical formula based on the ,-vector formalism of Hoffman and Cahn. We now have analytic criteria for missing orientations (sharp corners or edges) on the equilibrium shape, both in two (classical) and three (new) dimensions. Crystals that grow under the control of interfacial kinetic processes tend asymptotically toward a "kinetic Wulff shape", the analogue of the Wulff shape, except it is based on the anisotropic interfacial kinetic coefficient. If it were not for long range transport, crystals would presumably nucleate with their equilibrium shape and then evolve toward their "kinetic Wulff shape". Allowing for long range transport leads to morphological instabilities on the scale of the geometric mean of a transport length (typically a diffusivity divided by the growth speed) and a capillary length (of the order of atomic dimensions). Resulting crystal growth shapes can be cellular or dendritic, but can also exhibit corners and facets related to the underlying crystallographic anisotropy. Within the last decade, powerful phase field models, based on a diffuse interface, have been used to treat simultaneously all of the above phenomena. Computed morphologies can exhibit cells, dendrites and facets, and the geometry of isotherms and isoconcentrates can also be determined. Results of such computations are illustrated in both two and three dimensions. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Ionic and electronic processes in non-linear optical crystals

    PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2005
    Igor N. Ogorodnikov
    Abstract The paper presents the results of a study of the formation and decay of lattice defects in nonlinear optical crystals of NH4H2PO4 (ADP), KH2PO4 (KDP), Li2B4O7 (LTB) and LiB3O5 (LBO) with a sublattice of mobile hydrogen (ADP, KDP) and lithium (LTB, LBO) cations. By means of the luminescent and absorption optical spectroscopy with (the) a nanosecond time resolution under excitation with an electron beam, it was revealed that the optical absorption of these crystals in the visible and UV spectral ranges is produced by optical hole-transitions from the local defect level to the valence band states. The valence band density of the states determines the optical absorption spectral profile, and the relaxation kinetics is rated by the interdefect radiationless tunnel recombination between the trapped hole center and the H0 and Li0 electron trapped centers. At 290 K, the H0 and Li0 centers are subject to thermally stimulated migration. All manifestations of a radiative recombination observed in these crystals are accounted for by the involvement of additional electronic and hole centers of a different nature in the recombination process. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]