Structural evolution and second harmonic properties of lithium niobate-tantalate nanocrystals embedded in a borate glass

Nano-crystals of LiNbxTa1 (-) O-x(3) were evolved by subjecting melt-quenched 1.5Li(2)O-2B(2)O(3)-xNb(2)O(5)-(1 - x)Ta2O5 glasses (where x = 0, 0.25, 0.5, 0.75 and 1.00) to a controlled 3-h isothermal heat treatment between 530 and 560 degrees C. Detailed X-ray diffraction and Raman spectral studies confirmed the formation of nano-crystalline LiNbxTa1 (-) O-x(3) along with a minor phase of ferroelectric and non-linear optic Li2B4O7. The sizes of the nanocrystals evolved in the glass were in the range of 19-37 nm for x = 0-0.75 and 23-45 nm for x = 1.00. Electron microscopic studies confirmed a transformation of the morphology of the nano-crystallites from dendritic star-shaped spherulites for x = 0 to rod-shaped structures for x = 1.00 brought about by a coalescence of crystallites. Broad Maker-fringe patterns (recorded at 532 nm) were obtained by subjecting the heat-treated glass plates to 1064 nm fundamental radiation. However, an effective second order non-linear optic coefficient, d(eff), of 0.45 pm/V, which is nearly 1.2 times the d(36) of KDP single crystal, was obtained for a 560 degrees C/3 h heat-treated glass of the representative composition x = 0.50 comprising 37 nm sized crystallites. (C) 2015 Elsevier B.V. All rights reserved.

Structural evolution and second harmonic properties of lithium niobate-tantalate nanocrystals embedded in a borate glass

Nano-crystals of LiNbxTa1 (-) O-x(3) were evolved by subjecting melt-quenched 1.5Li(2)O-2B(2)O(3)-xNb(2)O(5)-(1 - x)Ta2O5 glasses (where x = 0, 0.25, 0.5, 0.75 and 1.00) to a controlled 3-h isothermal heat treatment between 530 and 560 degrees C. Detailed X-ray diffraction and Raman spectral studies confirmed the formation of nano-crystalline LiNbxTa1 (-) O-x(3) along with a minor phase of ferroelectric and non-linear optic Li2B4O7. The sizes of the nanocrystals evolved in the glass were in the range of 19-37 nm for x = 0-0.75 and 23-45 nm for x = 1.00. Electron microscopic studies confirmed a transformation of the morphology of the nano-crystallites from dendritic star-shaped spherulites for x = 0 to rod-shaped structures for x = 1.00 brought about by a coalescence of crystallites. Broad Maker-fringe patterns (recorded at 532 nm) were obtained by subjecting the heat-treated glass plates to 1064 nm fundamental radiation. However, an effective second order non-linear optic coefficient, d(eff), of 0.45 pm/V, which is nearly 1.2 times the d(36) of KDP single crystal, was obtained for a 560 degrees C/3 h heat-treated glass of the representative composition x = 0.50 comprising 37 nm sized crystallites. (C) 2015 Elsevier B.V. All rights reserved.

Tensile properties of thermally exposed aluminium borate whisker reinforced 6061 aluminium alloy composite

The effect of thermal exposure on the tensile properties of aluminium borate whisker reinforced 6061 aluminium alloy composite was studied. The interfacial reaction was investigated by TEM and the mechanical properties were studied using tensile tests. The results indicated that the interfacial reaction had an influence on the mechanical properties of the composite, so that the maxima of Young’s modulus and ultimate tensile strength of the composite after exposure at 500?C for 10 h were obtained for the optimum degree of interfacial reaction. The yield strength,however, was not only affected by the interfacial state but also by many other factors.

Degenerated optical parametric chirped-pulse amplification with cesium lithium borate

A gain amplifier for degenerated optical parametric chirped-pulse amplification (OPCPA) with lithium triborate and cesium lithium borate (CLBO) crystals was demonstrated in a near-collinear configuration, The signal gain of the final energy amplifier with CLBO was similar to 6. After compression, the 123 fs pulse duration was obtained. Compared with potassium dihydrogen phosphate, it is confirmed that CLBO is more effective as a nonlinear crystal in a final power amplifier for terawatt or petawatt OPCPA systems. To our knowledge, this is the first demonstration of OPCPA with CLBO. (c) 2006 Optical Society of America.

Distribution of the microcrystallites generated in borate glass irradiated by femtosecond laser pulses

This paper deals with the distribution of generated microcrystallites in borate glass irradiated by 120 fs laser pulses at a central wavelength of 800 nm. Raman spectroscopy is used to investigate the distribution of the high and low temperature phases of barium metaborate crystals generated in the borate glass. In combination with a microexplosion model, bond-breaking induced by laser irradiation is served as the origin of the formation of BBO crystals. Depending on the laser fluence and cooling conditions, the distribution mechanisms have been discussed. (c) 2006 Elsevier B.V. All rights reserved.

Microstructure of the crystals generated in borate glass irradiated by femtosecond laser pulses

In this study, we examined the microstructure of crystals generated in borate glass by femtosecond laser irradiation (FSLI). The distribution of the high-temperature and low-temperature phases of barium metaborate crystals produced in the borate glass is analyzed using Raman spectroscopy. We then propose the possible mechanism for the generation of crystals in glass by FSLI.

Growth of beta barium borate (beta-BaB2O4) thin films on alpha barium borate (alpha-BaB2O4) substrates

Crystalline beta-BBO thin films have been successfully prepared on (001)-oriented Sr2+-doped alpha-BBO substrates using liquid phase epitaxy and pulsed laser deposition techniques. The films were characterized by X-ray diffraction and X-ray rocking curve (XRC). The present results manifest that the beta-BBO thin films grown on Sr2+-doped alpha-BBO substrates have larger degree of orientation f-value and smaller XRC FWHM than the ones grown on other reported substrates. Compared with other substrates, alpha-BBO has the same UV cutoff and the similar structure to beta-BBO. These results reveal that alpha-BBO single crystal may be a promising substrate proper to the growth of beta-BBO films. (c) 2005 Elsevier B.V. All rights reserved.

Infrared broadband emission of bismuth-doped barium-aluminum-borate glasses

We report near infrared broadband emission of bismuth-doped barium-aluminum-borate glasses. The broadband emission covers 1.3 mum window in optical telecommunication systems. And it possesses wide full width at half maximum (FWHM) of similar to 200nm and long lifetime as long as 350 mus. The luminescent properties are quite sensitive to glass compositions and excitation wavelengths. Based on energy matching conditions, we suggest that the infrared emission may be ascribed to P-3(1) --> P-3(0) transition of Bi+. The broad infrared emission characteristics of this material indicate that it might be a promising candidate for broadband optical fiber amplifiers and tunable lasers. (C) 2005 Optical Society of America.

Preparation of crystalline beta barium borate thin films on Sr2+-doped alpha barium borate substrates by liquid phase epitaxy

Thin films of beta barium borate have been prepared by liquid phase epitaxy on Si2+-doped alpha-BaB2O4 (alpha-BBO, the high temperature phase of barium berate) (001) and (110) substrates. The results of X-ray diffraction indicate that the films show highly (001) preferred orientation on (001)-oriented substrates while the films grown on (110) substrates are textured with (140) orientation. The crystallinity of these films was found to depend on growth temperature, rotation rate, dip time and orientation of substrate. Growth conditions were optimized to grow films with (001) orientation on (001) substrates reproducibly. The films show second harmonic generation of 400 nm light upon irradiation with 800 nm Ti: Sapphire femtosecond laser light. (c) 2005 Elsevier B.V. All rights reserved.

Thermal stress-induced birefringence in borate glass irradiated by femtosecond laser pulses

Thermal stress-induced birefringence in borate glass which has been irradiated by 800-nm femtosecond laser pulses is observed under cross-polarized light. Due to the high temperature and pressure formed in the focal volume, the material at the edge of the micro-modified region is compressed between the expanding region and the unheated one, then stress emerges. Raman spectroscopy is used to investigate the stress distribution in the micro-modified region and indicates the redistributions of density and refractive index by Raman peak shift. We suggest that this technique can develop waveguide polarizers and Fresnel zone plates in integrated optics.

Defects in LPE-grown beta-barium borate (beta-BaB2O4) thin films

Morphological defects in beta-barium borate (beta-BBO) thin films grown on Sr2+ -doped alpha-BBO substrates by liquid phase epitaxy (LPE) technique were studied by scanning electron micrograph (SEM), atomic force microscopy (AFM) and optical spectroscopy. The present results indicate that the main defects exit in beta-BBO thin films are microcracks and hollow structure. The formation of microcrack is due to the lattice mismatch and the difference of thermal expansion coefficients between substrate and film. The hollow structure might be caused during the combination of islands, which formed in the initial stage. (C) 2006 Elsevier GmbH. All rights reserved.

Tris(2,2 '-bipyridyl)ruthenium(II) electrochemiluminescent detection of coreactants containing aromatic diol group by the interaction between diol and borate anion

Previous studies show that aromatic diols inhibited Ru(bpy)(3)(2+) electrochemiluminescence (ECL), and all reported Ru(bpy)(3)(2+) ECL methods for the determination of aromatic diols-containing coreactants are based on inhibition of Ru(bpy)(3)(2+)/tripropylamine ECL. In this study, the interaction between diol and borate anion was exploited for Ru(bpy)(3)(2+) ECL detection of coreactants containing aromatic diol group using epinephrine as a model analyte. The interaction prevented from the inhibition of Ru(bpy)(3)(2+) ECL by aromatic diol group of epinephrine. As a result, epinephrine was successfully detected in the absence of tripropylamine simply by using borate buffer solution as the supporting electrolyte. Under the optimum conditions, the log of the ECL intensity increases linearly with the log of epinephrine concentrations over the concentration range of 1.0x10(-9)-1.0x10(-4) M. The detection limit is 5.0x10(-10) M at a signal-to-noise ratio of three. The proposed method exhibit wider dynamic range and better detection limit than that by inhibited Ru(bpy)(3)(2+) ECL method. The relative standard deviation for 14 consecutive determinations of 5 mu M epinephrine was 3.5%. The strategy by interaction with borate anion or boronate derivatives is promising for the determination of coreactants containing aromatic diol group or aromatic hydroxyl acid group. Such interaction can also be used to avoid interference from aromatic diols or aromatic hydroxyl acids.

Long lasting phosphorescence in Eu3+ and Ce3+ co-doped strontium borate glasses

Long lasting phosphorescence (LLP) was observed in Eu2+, Ce3+ co-doped strontium borate glasses prepared under the reducing atmosphere due to the emission of both Eu2+ and Ce3+. The methods of photoluminescence, thermoluminescence and phosphorescence were used to study the samples, and possible mechanism was suggested. The co-doping of Ce3+ ions poisoned the phosphorescence emission of Eu2+ because of the competition to obtain the trapped electron. The phosphorescence of Ce3+ in the sample decays more quickly than that of Eu2+, which is suggested for the reason that the emission energy of Ce3+ is higher or the distance between Ce3+ and electron traps of the glasses is longer.

Structure and non-linear optical properties of beta-barium borate

The non-linear optical (NLO) properties of crystalline beta-BaB2O4 (beta-barium borate, BBO) have been investigated from the chemical bond viewpoint. The contributions of each type of chemical bond to the total NLO coefficient have been quantitatively determined. The calculations indicate that the true space group of BBO is R3 rather than R3c.