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Measurement of the refractive index and attenuation length of liquid xenon for its scintillation light

Solovov, V. N.; Chepel, V.; Lopes, M. I.; Hitachi, A.; Marques, R. Ferreira; Policarpo, A. J. P. L.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
Relevância na Pesquisa
66.4%
The attenuation length and refractive index of liquid xenon for its intrinsic scintillation light ([lambda]=178 nm) have been measured in a single experiment. The value obtained for the attenuation length is 364±18 mm. The refractive index is found to be 1.69±0.02. Both values were measured at a temperature of 170±1 K.; http://www.sciencedirect.com/science/article/B6TJM-49J93GG-5/1/7efa40cf2d4dc7beeee408098a2b6cfb

Combination of guided mode and photometric optical metrology methods for precise determination of refractive index dispersion: application to polymer blend and ceramic thin films for gas sensors

Wood, Thomas; Le Rouzo, Judikaël; Flory, François; Coudray, Paul; Mastelaro, Valmor Roberto; Pelissari, Pedro; Zilio, Sérgio Carlos
Fonte: International Society for Optical Engineering - SPIE; Bellingham Publicador: International Society for Optical Engineering - SPIE; Bellingham
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.4%
Two optical techniques, m-lines and spectroscopic ellipsometry, are compared for their suitability for obtaining the wavelength and the temperature dispersion of the refractive index of thin-film layers used in gas detector devices. Two types of materials that are often integrated into gas sensors are studied: a polymer organic-inorganic blend deposited by spin coating typically used in near-infrared waveguides and the ceramic semiconductor SrTi1-xFexO3 (strontium titanate) doped with iron at concentrations x = 0.075 and 0.1 deposited by electron beam deposition. The refractive index dispersion obtained by m-lines and ellipsometry is compared, and the differences between the measured parameters for the two materials are discussed. The chromatic dispersion will be represented by a three-term Cauchy law. An intuitive method for verifying the measured indices using an integrating sphere and reflexion coefficient modeling techniques are also demonstrated. Thermo-optic coefficients in the order of -1 × 10-4/K for both materials are reported, and very low chromatic dispersions are also measured, thanks to the high sensitivity of the m-lines technique. The uniaxial anisotropic properties of the polymerblend films are measured and discussed in the case of the semiconductor films.; ANR; CAPES/COFECUB

Refractive index changes in photochromic SbPO4-WO3 glass by exposure to band-gap radiation

Ahlawat, Meenu; Vazquez, Gloria V.; Nalin, Marcelo; Messaddeq, Younes; Ribeiro, Sidney; Kashyap, Raman
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 2360-2362
ENG
Relevância na Pesquisa
66.4%
We report photoinduced photo-darkening in SbPO4-WO3 glass by exposure to 532 nm light with a power density of 143 mW/cm(2). The time of exposure was varied between 0 and 256 min following which visible photo-darkening, peaking at 850 nm was observed. Spectrophotometer measurement of absorption was performed for both treated and untreated regions of the sample. Time exposure to below band-gap light results in a single exponent Gaussian absorption function over an exceptionally wide range of wavelengths (500 nm-1600 nm), with a 1/e width of 647.5 nm. Kramers-Kronig transform of the change in the absorption indicates a negative local change in the refractive index. The dispersed refractive index change at 1550 nm, Delta n, is calculated to be similar to -5 x 10(-8). The peak absorption increases with time of exposure and the photo-darkening remains irreversible at room temperature. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

Temporal evolution of sulfated zirconia sol-gel during dip coating: Analysis of mass drainage with time-varying refractive index

Michels, A. F.; Menegotto, T.; Santilli, C. V.; Horowitz, F.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 5362-5367
ENG
Relevância na Pesquisa
66.4%
The formation of sulfated zirconia films from a sol-gel derived aqueous suspension is subjected to double-optical monitoring during batch dip coating. Interpretation of interferometric patterns, previously obscured by a variable refractive index, is now made possible by addition of its direct measurement by a polarimetric technique in real time. Significant sensitivity of the resulting physical thickness and refractive index curves (uncertainties of ±7 nm and ±0.005, respectively) to temporal film evolution is shown under different withdrawal speeds. As a first contribution to quantitative understanding of temporal film formation with varying nanostructure during dip coating, detailed analysis is directed to the stage of the process dominated by mass drainage, whose simple modeling with temporal t-1/2 dependence is verified experimentally. © 2006 Elsevier B.V. All rights reserved.

Evaluation of electrical conductivity, pH and refractive index as physico-chemical parameters for quality control of Aveloz homeopathic solutions

da Silva, Isabella de Oliveira; Harduim, Rafael Cardoso; Zacharias, Carlos Renato; Garcia, Sheila; Holandino, Carla
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 108-109
ENG
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66.51%
Euphorbia tirucalli Lineu (Aveloz) belongs to the family Euphorbiaceae and is used in the treatment of cancer and warts. Some studies have reported that phorbol esters are the active principles responsible for the antitumor activity of Aveloz. The production of these molecules occurs in greater quantity in May, during the morning. This study aimed to evaluate whether the physico-chemical parameters of Aveloz homeopathic aqueous solutions such as pH, electrical conductivity and refractive index change due to storage time. Such parameters were measured regularly for 180 days. All solutions were prepared according to the method of grinding with lactose and subsequent dissolution in aqueous medium, as described in the Brazilian Homeopathic Pharmacopoeia, using as starting point the Aveloz latex collected in May. Homeopathic aqueous solutions containing only lactose were also prepared and evaluated as a control group. The potencies that were analyzed for electrical conductivity, pH and refractive index were: 4cH, 7cH, 9cH, 12cH, 14cH, 15cH, 29cH, 30cH. As a result, we found out that there was only statistical difference (p=0.035) in electrical conductivity between the homeopathic solutions containing Aveloz and the homeopathic solutions without Aveloz...

Equivalences between refractive index and equilibrium water content of conventional and silicone hydrogel soft contact lenses from automated and manual refractometry

González-Méijome, José Manuel; López-Alemany, António; Lira, Madalena; Almeida, José B.; Oliveira, M. Elisabete; Parafita, Manuel A.
Fonte: Wiley InterScience Publicador: Wiley InterScience
Tipo: Artigo de Revista Científica
Publicado em /05/2006 ENG
Relevância na Pesquisa
66.55%
PURPOSE: The purpose of the present study was to develop mathematical relationships that allow obtaining equilibrium water content and refractive index of conventional and silicone hydrogel soft contact lenses from refractive index measures obtained with automated refractometry or equilibrium water content measures derived from manual refractometry, respectively. METHODS: Twelve HEMA-based hydrogels of different hydration and four siloxane-based polymers were assayed. A manual refractometer and a digital refractometer were used. Polynomial models obtained from the sucrose curves of equilibrium water content against refractive index and vice-versa were used either considering the whole range of sucrose concentrations (16-100% equilibrium water content) or a range confined to the equilibrium water content of current soft contact lenses ( approximately 20-80% equilibrium water content). RESULTS: Values of equilibrium water content measured with the Atago N-2E and those derived from the refractive index measurement with CLR 12-70 by the applications of sucrose-based models displayed a strong linear correlation (r(2) = 0.978). The same correlations were obtained when the models are applied to obtain refractive index values from the Atago N-2E and compared with those (values) given by the CLR 12-70 (r(2) = 0.978). No significantly different results are obtained between models derived from the whole range of the sucrose solution or the model limited to the normal range of soft contact lens hydration. CONCLUSIONS: Present results will have implications for future experimental and clinical research regarding normal hydration and dehydration experiments with hydrogel polymers...

The effect of lens wear on refractive index of conventional hydrogel and silicone-hydrogel contact lenses : a comparative study

Lira, Madalena; Santos, Lívia; Azeredo, Joana; Yebra-Pimentel Vilar, Eva; Oliveira, M. Elisabete
Fonte: Elsevier Ltd. Publicador: Elsevier Ltd.
Tipo: Artigo de Revista Científica
Publicado em /04/2008 ENG
Relevância na Pesquisa
66.5%
Purpose: The purpose of this work was to evaluate the ability of four silicone-hydrogel contact lenses (galyfilcon A, balafilcon A, lotrafilcon A and lotrafilcon B) to retain their equilibrium water content before and after wear, through measurements of refractive index and compare with that of a conventional disposable hydrogel contact lens (etafilcon A). Methods: The refractive indices of 115 contact lenses were measured using an automated refractometer (CLR 12-70, Index Instruments, Cambridge, U.K.) before and after a schedule of daily wear by 58 patients for 30 days in the case of silicone-hydrogel lenses and 15 days for the conventional contact lenses. Results: In the silicone-hydrogel contact lenses the changes on the refractive indices were not statistically significant, however after being worn the refractive index of the conventional etalfilcon A hydrogel contact lens increased significantly ( p < 0.001). Conclusion: The results presented here show that after being worn the silicone-hydrogel contact lens, show more capacity to retain or to reach their initial equilibrium water content than conventional hydrogel contact lenses. This suggests that the silicone-hydrogel contact lenses are less susceptible to spoilation over time maintaining its biocompatibility and contributing to the clinical success of lens performance.; Bausch & Lomb; Vision and Johnson & Johnson.

Surface roughness and refractive index changes in contact lens induced by lens care systems

Lira, Madalena; Franco, Sandra; Vazquez-Dorrio, José B.; Oliveira, M. Elisabete; Costa, Manuel F. M.
Fonte: LWW Publicador: LWW
Tipo: Artigo de Revista Científica
Publicado em /05/2014 ENG
Relevância na Pesquisa
66.3%
Purpose: The aim of this study was to analyze the influence of different lens care systems in surface roughness and refractive index (RI) of contact lenses (CL). This information provides us with a better understanding of how care solutions affect CL materials. Methods: Several CL and three commercially available and appropriate lens care solutions were used (two polyhexamethylene biguanide and one hydrogen peroxide care systems). Lenses were immersed in the lens care systems, and then measurements with CLR 12-70 digital automated refractometer and atomic force microscopy analysis on Tapping mode were recorded. The measurements were performed before and after the lenses were immersed in each care solution. Results: Significant changes were observed on the CL materials when exposed to lens care systems. All the materials changed, to a greater or lesser extent, their roughness and RI, after being immersed in the different solutions. The water content varied between 0% (Nelfilcon A in ReNu Multiplus, Senofilcon A in AOSEPT Plus, and Methafilcon A in Solocare Aqua) and 4.1% (Hilafilcon B in Solocare Aqua) The higher change in roughness was obtained with ReNu Multiplus in the lens Comfilcon A (with an increase of 27.2 nm) and Senofilcon A (with an increase of 16.7 nm). Conclusion: This study suggests that lens care systems play an important role in surface roughness and RI of CL.; Fundação para a Ciência e a Tecnologia (FCT)

Determination of refractive index contrast and surface contraction in waveguide channels using multiobjective genetic algorithm applied to spectroscopic ellipsometry

Fernandes, Vasco R.; Santos Vicente, Carlos Miguel; Pecoraro, Edison; Karpinsky, Dmitry; Kholkin, Andrei L.; Wada, Naoya; André, Paulo S.; Ferreira, Rute A. S.
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.55%
The application of spectroscopic ellipsometry for the characterization of UV-patterned channel waveguides to obtain the refractive index contrast and surface deformation profile is presented. Thin films were prepared with organic-inorganic di-ureasils hybrids modified with zirconium tetra-propoxide deposited in silica on silicon substrates. The channel waveguides were produced by direct writing using UV laser radiation. The refractive index contrast and the surface ablation induced by the UV optical signal were estimated by ellipsometry being 4.5 x 10(-3) and 30.5 nm, respectively. The deepness of the surface ablation due to the UV exposition was also estimated by atomic force microscopy measurements that pointed out a value of 31.0 +/- 1.0 nm, concordant with the ellipsometric calculations. The near-field intensity technique was used as a support for contextualizing the proposed ellipsometry method for the characterization of refractive index profiles. The estimated refractive index contrast (2.0 x 10(-3)) is in a good agreement with the refractive index contrast derived from ellipsometry.

Refractive index matching applied to fecal smear clearing

Ferreira,Cláudio S.
Fonte: Instituto de Medicina Tropical Publicador: Instituto de Medicina Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2005 EN
Relevância na Pesquisa
66.4%
Thick smears of human feces can be made adequate for identification of helminth eggs by means of refractive index matching. Although this effect can be obtained by simply spreading a fleck of feces on a microscope slide, a glycerol solution has been routinely used to this end. Aiming at practicability, a new quantitative technique has been developed. To enhance both sharpness and contrast of the images, a sucrose solution (refractive index = 1.49) is used, which reduces the effect of light-scattering particulates. To each slide a template-measured (38.5 mm³) fecal sample is transferred. Thus, egg counts and sensitivity evaluations are easily made.

Dimensions and refractive index estimates of deeply buried optical waveguides in Lithium Fluoride

Chiamenti,Ismael; Bonfigli,Francesca; Montereali,Rosa Maria; Kalinowski,Hypolito J.
Fonte: Sociedade Brasileira de Microondas e Optoeletrônica e Sociedade Brasileira de Eletromagnetismo Publicador: Sociedade Brasileira de Microondas e Optoeletrônica e Sociedade Brasileira de Eletromagnetismo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
66.51%
A recursive procedure is applied to the measured near-field profiles of buried optical waveguides recorded in a lithium fluoride (LiF) crystal by femtosecond laser pulses in order to estimate the core dimensions and the refractive index increase. Albeit the waveguides transversal section geometry is quite complex it is possible to obtain the horizontal and vertical widths and the average refractive index maximum increase assuming a simplified rectangular transversal section in the simulation. The procedure is validated by comparing the simulated results with the experimental near-field profiles and the maximum refractive index values of two commercial optical fibers. Typical dimensions of ~(8x10)µm² and refractive index changes of ~(2-10)x10-4 were obtained for the LiF waveguides at several wavelengths.

Interferometric fiber sensor using exposed core microstructured optical fiber for refractive index based biochemical sensing

Nguyen, L.V.; Warren-Smith, S.C.; Cooper, A.; Monro, T.M.
Fonte: SPIE Publicador: SPIE
Tipo: Conference paper
Publicado em //2014 EN
Relevância na Pesquisa
66.4%
We proposed and experimentally demonstrated an in-fiber interferometric-type sensor by splicing an exposed core microstructured optical fiber (ECF) with lead-in and lead-out single mode fibers (SMFs) for refractive index-based biochemical sensing applications. Due to the multimode characteristic of the ECF, several modes can be excited at the lead-in splicing point and, after propagating through the ECF section, arrive at the lead-out splicing point with different phases forming a multi-arm interference pattern in the transmission spectrum of the device. Two dominant modes were found be consistently excited by maximizing the butt coupling between ECF and SMFs. The interference fringes shifts differently upon applying liquids of different refractive index on the exposed side of the EC.; Linh Viet Nguyen, Stephen C. Warren-Smith, Alan Cooper, Tanya M. Monro

Photonic crystal slot nanobeam slow light waveguides for refractive index sensing

Wang, Bowen; Dündar, Mehmet A.; Nötzel, Richard; Karouta, Fouad; He, Sailing; van der Heijden, Rob W.
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.4%
We present the design, fabrication, and photoluminescence experiment of InGaAsP photonic crystal slot nanobeam slow light waveguides with embedded InAs quantum dots. The strong confinement of electric field in the slot region is confirmed by the measured record high sensitivity of 7 x 10 (2) nm per refractive index unit RIU to the refractive index change of the environment. A cavity, formed by locally deflecting the two beams toward each other, gives an even higher sensitivity of about 9x10(2) nm/RIU.; The authors acknowledge the support from the BrainBridge project ZJU-TU/e and Philips Research collaboration, AOARD, and the National Natural Science Foundation of China Grant No. 60907018.

TUNABLE AND HIGH REFRACTIVE INDEX POLYDIMETHYLSILOXANE POLYMERS FOR LABEL-FREE OPTICAL SENSING

Little, JESSAMYN
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
66.67%
There is a need for chemical sensors for monitoring volatile organic compounds (VOCs) in air. Acute and chronic inhalation of toxic VOCs can cause adverse health effects in humans, so monitoring these analytes is important for ensuring that their concentrations are maintained below maximum permissible levels. Chemical sensors using polydimethylsiloxane (PDMS) to extract VOCs with partial selectivity, coupled with label-free optical detection methods based on refractive index, can overcome the limitations of conventional VOC detection methods. A variety of tunable and high refractive index PDMS materials were developed by incorporating a range of titanium and zirconium concentrations (2.5 – 30 mol % and 2.5 – 15 mol %, respectively) using a simple sol-gel synthesis and by incorporating a range of titanium concentrations (2.5 – 10 mol %) into naphthyl-functionalized PDMS. These materials ranged in refractive index from 1.4023 ± 0.0002 to 1.5663 ± 0.0001 at 635 nm and 1.3942 ± 0.0003 to 1.5510 ± 0.0007 at 1550 nm. The ability to use tunable refractive index PDMS films to differentiate between m-xylene and cyclohexane was demonstrated by monitoring changes in refractive index and thickness following absorption of these analytes using a refractometer at 1550 nm. The sensitivity of the refractive index response to an analyte using a particular PDMS film was dependent upon the difference between the refractive index of the analyte and film...

Bend Loss in Silica Optical Fibre with Low Refractive Index Coating

Bulla, Douglas; Love, John
Fonte: Conference Organising Committee Publicador: Conference Organising Committee
Tipo: Conference paper
Relevância na Pesquisa
66.42%
Silica optical fibre, coated with low refractive index material, was characterized against bend losses. The fibre showed low bend loss compared with similar fibre coated with standard refractive index material, and with a standard SMF.

Abnormal Transmittance of Refractive-Index-Modified ZnO/Organic Hybrid Films

Tsuzuki, Takuya
Fonte: John Wiley & Sons Ltd. Publicador: John Wiley & Sons Ltd.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.4%
The refractive index of ZnO/organic nanocomposite films was modified in the range from 1.44 to 1.55, while maintaining high visible transparency. The transparency of the nanocomposite films showed an abnormal behaviour as a function of the loading level o

Complex nonlinear refractive index of DNA

Samoc, Marek; Samoc, Anna; Grote, James G
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.4%
Femtosecond Z-scan technique was used to determine the dispersion of the complex cubic nonlinear susceptibility (related to the nonlinear refractive index n2 and the two-photon absorption coefficient β2) of deoxyribonucleic acid (DNA) in the range of wav

Plasmonic Nanoparticles: Factors Controlling Refractive Index Sensitivity

Miller, Molly McBain
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 4534178 bytes; application/pdf
EN_US
Relevância na Pesquisa
66.4%
Plasmonic nanoparticles support surface plasmon resonances that are sensitive to the environment. Factors contributing to the refractive index sensitivity are explored systematically through simulation, theory, and experiment. Particles small with respect to the wavelength of light and with size parameters much less than 1 have optical properties accurately predicted by quasi-electrostatic theory while particles with larger size parameters necessitate electrodynamics. A theory is developed that captures the effects of geometry on the refractive index sensitivity with a single factor, plasmon band location, and, although based on electrostatic theory, well predicts the sensitivity of particles whose properties are beyond the electrostatic limit. This theory is validated by high quality simulations for compact particles with shape parameters approaching 1 and, therefore, electrodynamic in nature, as well as higher aspect ratio particles that are electrostatic. Experimentally observed optical spectra for nanorods immobilized on glass and subjected to changes in n of the medium are used to calculate the sensitivity of the particles, found to be well matched by a variation on the homogeneous plasmon band theory. The separate electrostatic and electrodynamic components of plasmon band width...

Modulation of refractive index in polymer composites: toward a synthetic bio-optic lens

Smith, Thomas; Wnek, Gary
Fonte: SPIE: Proceedings of SPIE Publicador: SPIE: Proceedings of SPIE
Tipo: Artigo de Revista Científica Formato: 38660 bytes; application/pdf
EN_US
Relevância na Pesquisa
66.46%
As an option in the creation of a synthetic bio-optic lens, we propose that spatial modulation of refractive index can be realized in polymer composites containing a colloidal ionophoric phase. The variation of refractive index could result from electric field induced orientation or polarization of the dispersed phase. Devices are envisioned in which the refractive index gradient will be controlled by variation of the local applied field with matrix-addressed microelectrode arrays. Of particular utility in the demonstration of this phenomena are ionophoric and ionomeric block copolymers containing poly(ethylene oxide), PEO, poly(acrylic acid), PAA, and poly(methylmethacrylate), PMMA, chain segments. Systems that will be discussed relative to the provision of options in the creation of a synthetic biooptic lens are: (1) Electric field induced polarization of electrorefractive moieties localized in nanoscopic, salt-doped PEO domains of PS-b-PEO composites and (2.) localized deformation of salt-doped elastomeric PDMS-b-PEO composites.; The authors acknowledge support for this work from the Defense Advanced Research Projects Agency (DARPA) – Grant No. MDA972-02-C-0052.

Homogeneidade de índices de refração aplicada ao clareamento de esfregaços de fezes; Refractive index matching applied to fecal smear clearing

Ferreira, Cláudio S.
Fonte: Universidade de São Paulo. Instituto de Medicina Tropical de São Paulo Publicador: Universidade de São Paulo. Instituto de Medicina Tropical de São Paulo
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/12/2005 ENG
Relevância na Pesquisa
66.4%
Os esfregaços espessos de fezes humanas podem tornar-se adequados para a identificação de ovos e larvas de helmintos por meio da busca de homogeneidade de índices de refração. Embora seja possível obter esse efeito por meio de simples espalhamento de um fragmento de fezes sobre uma lâmina de microscopia, uma solução de glicerol tem sido usada rotineiramente para este fim. Visando à praticabilidade, elaborou-se uma técnica quantitativa em que é usada uma solução de sacarose (Índice de refração = 1,49) para reduzir o efeito da difusão da luz produzido por material particulado. O volume da amostra fecal a examinar em uma lâmina corresponde ao da cavidade cilíndrica da placa medidora (38,5 mm²). Avaliações de sensibilidade e contagens de ovos tornam-se, portanto, de fácil execução.; Thick smears of human feces can be made adequate for identification of helminth eggs by means of refractive index matching. Although this effect can be obtained by simply spreading a fleck of feces on a microscope slide, a glycerol solution has been routinely used to this end. Aiming at practicability, a new quantitative technique has been developed. To enhance both sharpness and contrast of the images, a sucrose solution (refractive index = 1.49) is used...