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Optical Applications (optical + application)
Selected AbstractsSol,Gel Derived Nanocomposites for Optical ApplicationsADVANCED ENGINEERING MATERIALS, Issue 5 2010Peter W. de Oliveira This paper provides a selective description of the development of nanostructured materials and the fabrication of the devices for optical applications. Examples are interference coatings, refractive and diffractive lenses, and macro- and micro-GRIN (graded refractive index) optical elements. Hybrid materials containing nanoparticles are of particular interest for the production of optical elements because, by exploiting the intrinsic solid state properties of the nanoparticles, nanocomposites can be tailored to exhibit the desired properties. A particular advantage of wet chemical processing lies in its great flexibility for depositing functional coatings. [source] Clean and Flexible Modification Strategy for Carboxyl/Aldehyde-Functionalized Upconversion Nanoparticles and Their Optical ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Huan-Ping Zhou Abstract Rare-earth upconversion nanoparticles (UCNPs) exhibit great potential in luminescent biolabels and other multifunctional probes; however, their applications are limited by their low water solubility and the lack of binding groups. To address these problems, a clean and flexible strategy to modify hydrophobic monodisperse UCNPs into hydrophilic ones that are capped with functional groups is developed. The modification process is implemented by direct oxidation of oleic acid ligands with ozone under specific conditions, where the oleic acid (OA) ligands on the surface of the UCNPs can be converted into azelaic acid ligands (HOOC(CH2)7COOH) or azelaic aldehyde HOOC(CH2)7CHO, as is revealed by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) measurements. This oxidation process has no significant side-effects on the morphology, phase, composition, or luminescent properties of the UCNPs. Free carboxylic acid groups on the surface endow the UCNPs with good water solubility, while aldehyde groups at the surface provide binding sites for amino-containing molecules via Schiff-base condensation, such as 2-(4-aminophenylethylyl)-5-methoxy-2-(2-pyridyl)thiazole (MPTEA) and 2-aminoethanethiol hydrochloride (NH2CH2CH2SH·HCl, HEMA). A Ce4+ sensor is constructed based on the dual-emission arising from the different spectral responses of MPTEA and the UCNPs. Facilitated by the covalent linkage between the terminal aldehyde group on the UCNPs and the amino group in HEMA, a hybrid structure of UCNPs and Au NPs is fabricated. The effective coupling between the aldehyde group and the amino group suggests that these functionalized UCNPs have potential in combining other functional units for simultaneous biolabeling, or other optical applications. [source] One- and Two-Dimensionally Structured Polymer Networks in Liquid Crystals for Switchable Diffractive Optical Applications,ADVANCED FUNCTIONAL MATERIALS, Issue 12 2004P. Kossyrev Abstract We have created one- and two-dimensionally structured polymer networks dispersed in a liquid-crystal solvent using a holographic exposure technique. These structures have potential for electrically switchable, reverse-mode, polarization selective and non-selective diffractive optical elements. Using a simple phenomenological model to describe our diffraction measurements in conjunction with microscopic studies, we are able to estimate the structured polymer wall thickness as a function of monomer concentration. [source] Photoluminescent Nanoparticle Surfaces: The Potential of Alkaline Earth Oxides for Optical Applications,ADVANCED MATERIALS, Issue 24 2008Andreas Sternig The surfaces of alkaline earth oxides emit bright, colored light and have potential as thermally stable inorganic phosphors with adsorption-dependent optical properties. The doping of thermally stable MgO nanocubes with low-coordinated BaO surface elements (see figure) clearly demonstrates that chemical manipulation of the solid,gas interface provides an efficient means to adjust the optical properties of powders in controlled gas atmospheres. [source] Donor-Embedded Polybinaphthalenes for Nonlinear Optical Applications: Influence of the Incorporation of a Double BondMACROMOLECULAR RAPID COMMUNICATIONS, Issue 11 2005Guy Koeckelberghs Abstract Summary: In this paper two new donor-embedded polybinaphthalenes prepared by the Heck reaction are presented. By introducing a double bond in the polymer backbone, the supramolecular structure was altered in comparison with polymers without the double bond. Comparison between the CD/UV-Vis spectra of polymers, with and without the double bond (previously synthesized in our laboratory) proved this change in a supramolecular structure. The double bonds also allow crosslinking upon heat treatment. NLO experiments demonstrated a more stable nonlinearity over time depending on the degree of crosslinking. [source] Low-Driving-Voltage Electroluminescence in Perovskite FilmsADVANCED MATERIALS, Issue 36 2009Hiroshi Takashima Perovskite thin-film electroluminescence devices are prepared, opening up a new optical application of perovskite materials. With increasing driving voltage, the intensity of electroluminescence increases dramatically. High-quality red color is produced and the working voltage for whole-surface electroluminescence is as low as 10 V. [source] Vibrational, optical and microhardness studies of trimethoprim DL -malateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2009S. Franklin Abstract Trimethoprim malate, an organic crystal, has been synthesized using slow evaporation method from its aqueous solution. Structural, optical and the mechanical properties of the grown crystal have been investigated by various characterization techniques which include FTIR spectra, single crystal XRD, UV-Vis spectra and Vickers microhardness testing. The structure of the compound predicted by analysing the recorded FTIR spectrum compliments the structure determined using single crystal X-ray diffraction. Single crystal X-ray diffraction study reveals that the crystals are monoclinic [P21/c, a=12.9850 Å, b=9.3038 Å, c=15.6815 Å and ,=111.065°]. The UV-Vis spectrum exhibits maximum transparency (98%) for a wide range suggesting the suitability of the title compound for optical applications. The optical constants have been calculated and illustrated graphically. Microhardness tests have been performed on the cystal under study and the Vicker hardness number has been calculated. The work hardening coefficient is found to be 2.85 which suggest that the crystal belongs to the family of soft materials. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Sol,Gel Derived Nanocomposites for Optical ApplicationsADVANCED ENGINEERING MATERIALS, Issue 5 2010Peter W. de Oliveira This paper provides a selective description of the development of nanostructured materials and the fabrication of the devices for optical applications. Examples are interference coatings, refractive and diffractive lenses, and macro- and micro-GRIN (graded refractive index) optical elements. Hybrid materials containing nanoparticles are of particular interest for the production of optical elements because, by exploiting the intrinsic solid state properties of the nanoparticles, nanocomposites can be tailored to exhibit the desired properties. A particular advantage of wet chemical processing lies in its great flexibility for depositing functional coatings. [source] Clean and Flexible Modification Strategy for Carboxyl/Aldehyde-Functionalized Upconversion Nanoparticles and Their Optical ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Huan-Ping Zhou Abstract Rare-earth upconversion nanoparticles (UCNPs) exhibit great potential in luminescent biolabels and other multifunctional probes; however, their applications are limited by their low water solubility and the lack of binding groups. To address these problems, a clean and flexible strategy to modify hydrophobic monodisperse UCNPs into hydrophilic ones that are capped with functional groups is developed. The modification process is implemented by direct oxidation of oleic acid ligands with ozone under specific conditions, where the oleic acid (OA) ligands on the surface of the UCNPs can be converted into azelaic acid ligands (HOOC(CH2)7COOH) or azelaic aldehyde HOOC(CH2)7CHO, as is revealed by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) measurements. This oxidation process has no significant side-effects on the morphology, phase, composition, or luminescent properties of the UCNPs. Free carboxylic acid groups on the surface endow the UCNPs with good water solubility, while aldehyde groups at the surface provide binding sites for amino-containing molecules via Schiff-base condensation, such as 2-(4-aminophenylethylyl)-5-methoxy-2-(2-pyridyl)thiazole (MPTEA) and 2-aminoethanethiol hydrochloride (NH2CH2CH2SH·HCl, HEMA). A Ce4+ sensor is constructed based on the dual-emission arising from the different spectral responses of MPTEA and the UCNPs. Facilitated by the covalent linkage between the terminal aldehyde group on the UCNPs and the amino group in HEMA, a hybrid structure of UCNPs and Au NPs is fabricated. The effective coupling between the aldehyde group and the amino group suggests that these functionalized UCNPs have potential in combining other functional units for simultaneous biolabeling, or other optical applications. [source] Efficient Luminescence from Rare-Earth Fluoride Nanoparticles with Optically Functional Shells,ADVANCED FUNCTIONAL MATERIALS, Issue 7 2006M. Lezhnina Abstract Rare-earth fluorides are a class of materials with considerable potential in optical applications. Fluoride lattices typically permit high coordination numbers for the hosted rare-earth ions, and the high ionicity of the rare-earth-to-fluorine bond leads to a wide bandgap and very low vibrational energies. These factors make rare-earth fluorides very useful in optical applications employing vacuum ultraviolet and near-infrared excitation. The preparation of nanometer-sized particles has opened the door for new properties and devices if the performance of their macroscopic counterparts can be conserved in the nanometer regime. However, at small particle sizes, defect surface states and adhering water reduce the optical efficiency. These shortcomings can be reduced by applying protective shells around the luminescent cores, which can also be involved in the luminescent process. [source] Luminescent Soft Material: Two New Europium-Based Ionic LiquidsHELVETICA CHIMICA ACTA, Issue 11 2009Sifu Tang Abstract Two new Eu-based ionic liquid systems, [C4mim][DTSA],:,[Eu(DTSA)3] and 2[C4mim] [DTSA],:,[Eu(DTSA)3] were synthesized at 120° under inert conditions from 1-butyl-1-methylimidazolium ditoluenesulfonylamide ([C4mim][DTSA]). The identity and purity of the synthesized compounds were confirmed by elemental analysis, IR, Raman, and 1H-NMR spectroscopy. As they solidify below 100° as glasses they qualify as ionic liquids. Fluorescence measurements show that the materials exhibit a strong red luminescence of high color purity. Therefore, they have the potential to be used for optical applications such as in emission displays. [source] Synthesis and Optical Properties of Soluble Polyimide/Titania Hybrid Thin FilmsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 12 2006Chih-Ming Chang Abstract Summary: In this study high-refractive-index polyimide/titania hybrid optical thin films were successfully prepared using a sol-gel process combined with spin coating and multistep baking. The hybrid thin films were prepared from a soluble polyimide, a coupling agent, and a titania precursor. Transparent hybrid thin films can be obtained at TiO2 content as high as 40 wt.-%. The FE-SEM results suggest that the TiO2 particles in the hybrid thin films have diameters in the nanometer range. The thermal decomposition temperatures of the prepared hybrid materials are above those of the respective polyimide except for the highest TiO2 content hybrids. The refractive indices at 633 nm of the prepared hybrid thin films increase linearly from 1.66 to 1.82 with increasing TiO2 content. The excellent optical transparency, thermal stability, and tunable refractive index provide the potentials of the polyimide/titania hybrid thin films in optical applications. [source] SU8 photoresist as an etch mask for local deep anodic etching of siliconPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003V. V. Starkov Abstract For the formation of an ordered porous structure, the distance between two nearest neighbor pores cannot be more than a certain size, otherwise random nucleated pores arise spontaneously between ordered pores. The "proximity effect" does not allow the production of macropores with variable interpore distances on the surface of Si wafers. More precisely, it does not allow one to increase arbitrarily the distance between single pores, which is necessary, for example, in the manufacture of photovoltaic devices with improved radiation hardness. Moreover, for many electronic, electromechanical, and optical applications, it is highly desirable to pattern porous silicon in defined two- and three-dimensional geometrical layouts. The simplest solution to such problems is anodic etching through a photoresist mask. In the present work, results on deep anodic etching of silicon through a mask of SU8 photoresist are presented. [source] YIG thin films for magneto-optical and microwave applicationsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2004T. Boudiar Abstract Thin films of Yttrium Iron Garnet (YIG) are grown by radio frequency magnetron non reactive sputtering system on quartz and Gadolinium Gallium Garnet (GGG) for optical applications or alumina substrates for microwave applications. A post deposition annealing is needed to obtain the crystallization of YIG films and the magnetic properties which are correlated with the magneto-optical properties. Their crystallographic, morphologic and magnetic properties are explored. The variation of Faraday rotation is studied versus the wavelength. For both optical substrates, quartz and GGG, results are comparable with the literature for bulk material. A microwave isolator was realized with YIG thin film on alumina substrate in a coplanar configuration. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The new pentaborate Na3SrB5O10ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2008Li Wu Sodium strontium pentaborate, Na3SrB5O10, maintains the same, previously unobserved, structure type at 200, 250 and 293,K. The fundamental building units are anionic [B5O10]5, groups distorted from mm2 point symmetry. The Sr atoms are eightfold coordinated by O atoms, forming trigonal dodecahedra. The Na atoms appear in three crystallographically different environments. The present single-crystal results correct a previous report in which a monoclinic cell was deduced for this compound on the basis of powder diffraction data. The structure of the title compound is discussed in the crystalochemical context of other borates with the same formula type. Although the unit cell of the present compound is similar to that determined in a previous study of the analogous Ca-containing compound, this study demonstrates that the structures of the two are different. These novel alkali,alkaline earth borates are considered as potential host materials for optical applications (fluorescence materials or phosphors). [source] | ||||||||||||||||||||||||||||