Wyniki wyszukiwania - Biblioteka Nauki

1

Growth and study of nonlinear optical crystals at the Hungarian Academy of Sciences

100%

Földvári I. , Polgár K. , Péter A. , Beregi E. , Szaller Z.

Journal of Telecommunications and Information Technology

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2000

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tom nr 1-2

37-41

EN

The former Research Laboratory for Crystal Physics continues the growth and defect structure investigation of nonlinear optical single crystals in a new organization, as a part of the Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences. The aim of the activity is to prepare specific crystals for basic and applied research as well as for applications. We improve the quality or modify the properties of well known nonlinear oxide and borate crystals and develop new materials. The principle nonlinear optical crystals in our profile are the followings: Paratellurite (TeO2), congruent, Mg-doped and stoichiometric lithium niobate (LiNbO3), a variety of sillenite structured crystals (Bi12MeO20, Me=Si, Ge, Ti, etc.), bismuth tellurite (Bi2TeO5) and nonlinear borates (BBO-beta-BaB2O4, LBO-LiB3O5, LTB-Li2B4O7, CLBO-CsLiB6O10 and YAB-YAI3(BO3)4). Details of the crystal preparation and the major achievements are discussed in the paper.

2

The development of lec technology for GaAs single crystal growth from laboratory scale to mass production

80%

Jurisch M. , Eichler S.

Materiały Elektroniczne

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2003

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tom T. 31, nr 1-2

7-17

EN

Mass production of SI GaAs single crystals based on an advanced LEC growth process has been established during the last decade of the last century. Two key issues had to be solved : Scaling up of the growth equipment and carbon control. The progress in modelling of thermal heat transfer (radiation, conduction and turbulent convection) due to high computer power and advanced codes has made it possible to optizme the equipment and the processes in rather short time and at lower costs.

3

An efficient Monte Carlo Potts method for the grain growth simulation of single-phase systems

80%

Maazi N. , Lezzar B.

Computer Methods in Materials Science

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2020

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tom Vol. 20, No. 3

85--94

EN

The choice of the lattice sites to be reoriented in the Monte Carlo Potts algorithm for grain growth simulation is repeated in a non-homogeneous way. Therefore, some grains are favorably growing than others. This fact may seriously affect the simulation results. So a modified MC method is presented. Lattice sites are selected for reorientation one by one following their positions in the matrix in each Monte Carlo step (mcs). This approach ensures that the various selections of one lattice site within every mcs are eliminated, and no favorable growth of grains at the expense of others. The calculation time considerably decreases. The effect of real-time and physical temperature on the grain growth kinetics is discussed.

4

Solidification microstructure in a supercooled binary alloy

80%

Wang H. , Tang C. , An H. , Zhao Y.

Materials Science Poland

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2021

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tom Vol. 39, No. 3

383--394

EN

The maximum undercooling that has been achieved for Ni-Cu alloy, by using molten glass purification and cyclic super-heating technology, is 270 K. With the help of high-speed photography, the solidification front images of Ni-Cu alloy at various typical undercooling were obtained. Two grain refinements occurred in the range of 60 K< ΔT < 100 K and ΔT > 170 K, the solidification front became smoother, and the solidification position appeared randomly. With the increase of undercooling, the transition from solute diffusion to thermal diffusion leads to the transition from coarse dendrite to directional fine dendrite. At large undercooling, considerable stress is accumulated and some dislocations exist in the microstructure. However, the proportion of high-angle grain boundaries is as high as 89%, with twin boundaries of 13.6% and most strain-free structures, and the microhardness decreases sharply. This indicates that the accumulated stress at large undercooling causes the plastic strains in the microstructure, and in the later stage of recalescence, part of the plastic strains is dissipated by the system and acts as the driving force to promote the recrystallization of the microstructure.

5

Influence of L-threonine on the growth, structural, optical, mechanical and nonlinear optical properties of tartaric acid single crystal

80%

Thilakavathi G. , Arun Kumar R. , Gunasekaran V.

Materials Science Poland

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2018

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tom Vol. 36, No. 4

630--637

EN

Single crystals of pure and L-threonine added tartaric acid (LT/TA), organic nonlinear optical (NLO) materials were grown from their respective aqueous solution by slow evaporation method. The crystalline nature of the grown crystals was confirmed by powder X-ray diffraction analysis (XRD). UV-Vis-NIR absorption and transmission spectra revealed that the lower cut-off wavelength was around 281 nm and the crystals exhibited high transmission over visible and near IR region. The presence of the functional groups such as O–H, C–H, C–O, C=O in the grown crystals was confirmed by FT-IR analysis. CHN analysis was carried out to confirm the presence of L-threonine in the grown crystals. Microhardness study on the crystals revealed that the hardness number Hv increased with the applied load. The growth pattern of the crystals were analyzed through etching analysis from which the etch patterns in the shape of 'step-triangle' were observed. The second harmonic generation (SHG) properties of pure and L-threonine doped tartaric acid crystals were confirmed by Kurtz-Perry powder technique.

6

Morphology and the kinetics of the crystal growth

80%

Jakubczyk M. , Kopyciak G.

Prace Naukowe. Chemia i Ochrona Środowiska / Akademia im. Jana Długosza w Częstochowie

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2005

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tom Vol. 10

59--63

7

Growth of large SbSI crystals

80%

Szperlich P. , Toron B. , Nowak M. , Jesionek M. , Kepinska M. , Bogdanowicz W.

Materials Science Poland

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2014

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tom Vol. 32, No. 4

669--675

EN

In this paper a novel method of SbSI single crystals fabrication is presented. In this method a sonochemically prepared SbSI gel is used as an intermediate product in a vapour growth process. The main advantages of the presented technique are as follows. First, the SbSI gel source material has lower temperature of sublimation and allows to avoid explosions during SbSI synthesis (the sonochemical synthesis is free of any explosion hazard). Second, but not least, the grown SbSI single crystals have smaller ratio of longitudinal and lateral dimensions. The cross sections of the presented crystals are relatively large (they are up to 9 mm2 ). The crystals have been characterized by X-ray diffraction, angle-resolved optical spectroscopy, and diffusive reflectivity.

8

Synthesis of claw-like CuO and its catalytic activity in the thermal decomposition of ammonium perchlorate

80%

Wang J. , He S. , Li Z. , Jing X. , Zhang M.

Materials Science Poland

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2009

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tom Vol. 27, No. 2

501--507

EN

Claw-like CuO was prepared by solution process at 100 °C simply by using copper nitrate and hexamethylenetetramine for 3 h. The structure and morphology of resulting CuO powders were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. CuO nanocrystals were studied as an additive for promoting the thermal decomposition of ammonium perchlorate. With the addition of the claw-like CuO nanocrystals, thermal decomposition temperature of ammonium perchlorate decreased. CuO nanocrystals showed catalytic activity on the decomposition of ammonium perchlorate.

9

Growth and characterization of an NLO material - crystal of triglycine acetate

80%

Hussaini S. S. , Dhumane N. R. , Dongre V. G. , Shirsat M. D.

Materials Science Poland

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2009

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tom Vol. 27, No. 2

365--372

EN

Triglycine acetate (TGAc), a nonlinear optical material, has been synthesized. The second harmonic generation efficiency has been determined by Kurtz's powder test and it was found to be 1.55 times more than potassium dihydrogen phosphate. The solubility studies were carried out in the temperature range 30-55 °C. Single crystals of TGAc have been grown by slow evaporation of solution at 30 °C. The cell parameters were determined by the X-ray diffraction analysis. The UV-visible absorption spectra have been recorded to study the optical transmittance in the range from 200 nm to 800 nm. The Fourier transform infrared analysis identified various functional groups present in the material. The mass spectral analysis was carried out to measure the total molecular weight of the grown crystal. Using thermogravimetric analysis the thermal behaviour was studied.

10

Investigation on Nucleation Kinetics, Growth and Nonlinear Optical Properties of L-Cystine Hydrochloride Crystal

80%

Manivannan D. , Kirubavathi K. , Selvaraju K.

Acta Physica Polonica A

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2018

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tom 133

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nr 1

63-67

EN

The semiorganic nonlinear optical crystal of amino-carboxyl acid family, L-cystine hydrochloride (LCHCl) was successfully grown from its aqueous solution by the slow evaporation solution growth method. The solubility, metastable zone width and induction period were determined for the first time experimentally and there by the possibility of growing bulk crystals of LCHCl using deionized water as solvent. The induction period was recorded for the different supersaturation ratios (S=1.2, 1.3, 1.4, and 1.5), which reveals that the induction period of LCHCl decreases with increase in supersaturation. The nucleation kinetic parameters such as critical free energy, change of volume free energy, critical radius, number of molecules in the critical nucleus and nucleation rate have been evaluated for LCHCl crystals. The interfacial energy values of LCHCl were determined for different supersaturation ratio by means of varying temperatures. The single crystal X-ray diffraction gives the lattice parameters value of the grown crystals. The second harmonic generation efficiency was confirmed by the Kurtz-Perry powder method. The laser damage threshold energy of the grown crystal indicates that grown crystal has excellent resistance to laser radiation also compared with known other nonlinear optical crystals.

11

Crystal growth and characterisation of In-rich phases in Cu-In-Ga-Se system

80%

Filipowicz J. I. , Bacewicz R. , Wolska A.

Opto-Electronics Review

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2000

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tom Vol. 8, No. 4

372-374

EN

Technological parameters of crystal growth using Bridgman-Stockbarger method for some materials of Cu-In-Se and Cu-In-Ga-Se systems are presented. Single crystals as large as 1 cm³ have been grown. The composition variation along crystal ingots was determined by the microprobe analysis. A strong segregation effect is observed. Crystals with composition close to the compounds with nominal compositions Cu₂In₄Se₇, CuIn₃Se₅, CuIn₅Se₈, CuGa₃Se₅ and Cu(In₀.₈Ga₀.₂)₃Se₅ were identified. Photolumiscence spectra of the crystals from the Cu-In-Se system were measured and analysed in terms of quasi-donor-acceptor transitions.

12

Magnetic properties of manganese doped PrAlO3 monocrystalline fibres

80%

Guzik A. , Talik E. , Pajączkowska A. , Turczyński S. , Kusz J.

Materials Science Poland

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2014

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tom Vol. 32, No. 4

633--640

EN

Monocrystalline fibres of undoped PrAlO3 and PrAlO3:0.1 Mn, have been grown by the pulling-down method under nitrogen atmosphere. The as-grown crystal doped with Mn had a visible brown core surrounded by a green ring, whereas this effect was weaker for the undoped PrAlO3. A coloration of the brown core was caused by a presence of Pr4+ ions. The presence of the Pr4+ ions was confirmed by XPS and magnetic studies. The XPS chemical analysis showed the increased concentration of oxygen in the crystals with the brown core. The most probable valency of manganese is Mn4+. It is located in Al3+ sites.

13

Synthesis, growth and characterization of NaAl(SO4)·H2O triangular prism single crystal for inorganic NLO application

80%

Sakthi P. , Rajasekaran R. , Arun A.

Materials Science Poland

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2019

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tom Vol. 37, No. 2

142--148

EN

An inorganic coordination complex of single crystal containing sodium and aluminum (SA) was grown at room temperature by slow evaporation technique. The crystal was characterized using single crystal X-ray diffraction (XRD), FT-IR, UV-Vis, SHG, SEM, EDX and TG/DTA analyses. The size of the grown crystal was around 17 mm × 15 mm × 5 mm. Both optical and SEM photographs confirmed that the crystal is transparent with smooth surface. The XRD data showed that the crystal belongs to the BCC crystal structure. The crystal shows excellent transparency in the entire region of visible light (cut-off value is 339 cm−1 ). The dielectric constant as well as dielectric loss of the sample was calculated by varying frequencies at different temperatures and the presence of low dielectric loss proved that this crystal can be used for the NLO application.

14

Growth and optical properties of Nd:YVO₄ laser crystals

80%

Kaczmarek S. M. , Łukasiewicz T. , Giersz W. , Jabłoński R. , Jabczyński J. K. , Świrkowicz M. , Gałązka Z. , Drozdowski W. , Kwaśny M.

Opto-Electronics Review

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1999

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tom Vol. 7, No. 2

149-152

EN

Growth conditions for Nd:YVO₄ crystals and some optical properties are presented. The obtained Nd:YVO₄ crystal shows lower content of point defects and consequently, lower susceptibility to ionising radiation. ESR measurements show the presence of V ions in intersitial sites with another than 5t valency. Obtained by Czochralski method crystals reveal very good optical properties, some of which are better than for Nd:YAG.

15

YAG:V³⁺ : new passive Q-switch for lasers generating radiation within near infrared range

80%

Mierczyk Z. , Frukacz Z.

Opto-Electronics Review

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2000

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tom Vol. 8, No. 1

67-74

EN

The paper presents results of investigations on growth conditions of yttrium-aluminium garnet doped with trivalent vanadium YAG:V³⁺ ions and investigations of these crystals for their application in passive Q-switches of laser resonators generating radiation within near infrared range. Absorption spectra of the crystals were examined. It was sated that within a spectral range of 720-1500 nm there are three absorption bands with their maxima for the wavelengths of 822 nm, 1098 nm, and 1282 nm. For these maxima the crystal absorption is nonlinearly dependent on intensity of incident radiation, i.e., crystal is a saturable absorber. The process of reduction of V⁵⁺ and V⁴⁺ ions to V³⁺ ones was carried out by means of crystals heating what significantly increases concentration of V³⁺ ions that are responsible for nonlinear absorption. Saturation characteristics have been determined and modulation properties in the systerm of YAG:Nd laser, generating giant-pulses of wavelengths of 1064 nm and 1318 nm have been investigated. Detailed review of the literature and the results of hitherto carried out investigations have been also performed.

16

Crystal growth of the oxide fiber single crystal for optical applications

80%

Yoon D. H.

Opto-Electronics Review

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2004

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tom Vol. 12, No. 2

199-212

EN

Recently, certain materials have attracted attention for a new generation of high speed, efficient, multi-functional optical devices. Among these materials, small-diameter and long-length bulk crystals are of considerable interest for miniaturization and high efficiency. In particular, rod or fiber-like micro-single crystals have already received attention as attractive materials for a variety of electro-optical application, such as second harmonic generation (SHG), micro-laser sources or optical memory arrangements because of their extended interaction length and high optical intensity.

17

Synthesis and formation process of zirconium dioxide nanorods

80%

Pei L. Z. , Xie Y. K. , Pei Y. Q. , Yuan C. Z.

Materials Science Poland

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2013

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tom Vol. 31, No. 2

186--192

EN

Crystalline zirconium dioxide nanorods have been prepared by a simple hydrothermal process using zirconium hydroxide as the zirconium raw material. Zirconium dioxide nanorods are composed of monoclinic zirconium dioxide phase, which has been confirmed by the X-ray diffraction analysis. Electron microscopy observations show that the zirconium dioxide nanorods have a single crystal structure, with the rod diameter of less than 100 nm and length of 1 – 2 m. Hydrothermal temperature and reaction time play essential roles in the formation and growth of the zirconium dioxide nanorods. Nucleation and crystal growth process are proposed to explain the formation and growth of the zirconium dioxide nanorods.

18

Growth, characterization and optical properties of potassium iodide (KI) doped potassium hydrogen phthalate (KHP) single crystals for optoelectronic applications

80%

Raju R. K. , Beena P. , Jayanna H. S.

Materials Science Poland

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2019

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tom Vol. 37, No. 3

510--516

EN

Potassium iodide (KI) doped potassium hydrogen phthalate (KHP) single crystals were grown by slow evaporation technique using millipore water as a solvent. The grown single crystals were analyzed by powder X-ray diffraction and the analysis confirmed that KI-doped KHP crystallizes in orthorhombic system with space group Pca21. The functional groups were identified by FT-IR technique which showed slight shift in vibrational frequencies, indicating inclusion of dopant into the crystal lattice. The UV-Vis spectral studies revealed the optical transparency of the doped crystals in the entire visible region. The optical band gap values were estimated from Tauc plots. Kurtz-Perry powder test was employed for second harmonic generation efficiency studies of the grown crystals.

19

Growth and characterization of hexamethylenetetramine crystals grown from solution

80%

Babu B. , Chandrasekaran J. , Balaprabhakaran S.

Materials Science Poland

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2014

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tom Vol. 32, No. 2

164—170

EN

Organic nonlinear optical single crystals of hexamethylenetetramine (HMT; 10 × 10 × 5 mm3) were prepared by crystallization from methanol solution. The grown crystals were subjected to various characterization techniques such as single crystal XRD, powder XRD, UV-Vis and electrical studies. Single crystal XRD analysis confirmed the crystalline structure of the grown crystals. Their crystalline nature was also confirmed by powder XRD technique. The optical transmittance property was identified from UV-Vis spectrum. Dielectric measurements were performed as a function of frequency at different temperatures. DC conductivity and photoconductivity studies were also carried out for the crystal. The powder second harmonic generation efficiency (SHG) of the crystal was measured using Nd:YAG laser and the efficiency was found to be two times greater than that of potassium dihydrogen phosphate (KDP).

20

Investigation on optical, electrical and etching properties of 2-aminopyridinium 4-aminobenzoate: A phase matchable organic single crystal for optoelectronic device applications

70%

Chandra L. , Chandrasekaran J. , Perumal K. , Babu B. , Jayaramakrishnan V.

Materials Science Poland

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2017

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tom Vol. 35, No. 1

126--134

EN

NLO active 2-aminopyridinium 4-aminobenzoate (APAB) single crystals were successfully grown by the standard slow evaporation technique. The crystallinity of the grown crystals was analyzed through X-ray diffraction (XRD) measurements. Fourier transform infrared (FT-IR) spectroscopic studies were also performed for the identification of different modes present in the compound. The UV-Vis absorption and transmittance spectra were recorded for the grown crystal and the optical band gap was calculated. Birefringence and etching studies were also carried out. The dielectric study showed that the dielectric constant decreased with an increase in frequency. The photoconductivity study revealed its positive photoconducting nature. Theoretical HOMO LUMO investigations were also made for the crystal. The relative SHG efficiency of the material was investigated by the Kurtz and Perry powder technique. The phase matching property of the crystal was studied through the SHG dependence of average particle sizes.