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Aproximadamente 20 registro(s) hasta el momento: (journal)

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Recurso libre

Influences of recording geometry parameters on diffraction efficiency in bleached silver halide transmission holograms
Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	The experimental results of diffraction efficiency as a function of the geometrical disposition of recording beams in bleached silver halide transmission thick-holographic gratings are presented. Two variables have been used to relate these results with certain geometric parameters. These variables…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

Imaging in white light with a thick-phase transmission holographic doublet
Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	An afocal two-element holographic imaging system is presented. This system can be used to work in white light. The holographic optical elements (holographic lenses) are made as thick phase holograms on silver halide sensitized gelatin (SHSG) and they present a…
Fecha:	2009-01-30
Recurso:	RUA Docencia

Recurso libre

Calculation of the color matching functions of digital cameras from their complete spectral sensitivities
Martínez Verdú, Francisco Miguel - Pujol Ramo, Jaume - Capilla Perea, Pascual

Formato:	info:eu-repo/semantics/article
Enlaces:	We propose a new algorithm to obtain the color matching functions of any digital camera, with correct weights and white balance, from the relative scaling of their complete (3-D) spectral sensitivities obtained from real spectroradiometric data. Thanks to this algorithm,…
Fecha:	2007-09-11
Recurso:	RUA Docencia

Recurso libre

Efficiency of thick phase holograms in the presence of shear-type effects due to processing
Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	Based on the results of the coupled-wave theory the diffraction efficiency is calculated for thick phase transmission holographic gratings taking into account the chemical processing of the recording material. Three effects of processing are considered: variations in the average refractive…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

Color visualization system for near-infrared multispectral images
Vilaseca Ricart, Meritxell - Pujol Ramo, Jaume - Arjona Carbonell, Montserrat - Martínez Verdú, Francisco Miguel

Formato:	info:eu-repo/semantics/article
Enlaces:	The aim of this study is to develop a color visualization system for multispectral images in the near-infrared region (NIR, 800–1000 nm). Samples with the same color or appearance in the visible region, which are therefore indistinguishable to the human
Fecha:	2007-09-11
Recurso:	RUA Docencia

Recurso libre

Characterization of a digital camera as an absolute tristimulus colorimeter
Martínez Verdú, Francisco Miguel - Pujol Ramo, Jaume - Capilla Perea, Pascual

Formato:	info:eu-repo/semantics/article
Enlaces:	An algorithm is proposed for the spectral and colorimetric characterization of digital still cameras (DSC) which allows them to be used as tele-colorimeters with CIE–XYZ color output, in cd/m2. The spectral characterization consists in the calculation of the color-matching functions…
Fecha:	2007-09-11
Recurso:	RUA Docencia

Recurso libre

Corneal primary aberrations compensation by oblique light incidence
Espinosa Tomás, Julián - Mas Candela, David - Kasprzak, Henryk T.

Formato:	info:eu-repo/semantics/article
Enlaces:	The eye is not a centered system. The line of sight connects the fovea with the center of the pupil and is usually tilted in the temporal direction. Thus, off-axis optical aberrations, mainly coma and oblique astigmatism, are introduced at…
Fecha:	2009-09-04
Recurso:	RUA Docencia

Recurso libre

Weighted Zernike polynomial fitting in steep corneas sampled in Cartesian grid
Espinosa Tomás, Julián - Pérez Rodríguez, Jorge - Mas Candela, David - Illueca Contri, Carlos

Formato:	info:eu-repo/semantics/article
Enlaces:	Surfaces with radial structure do not fit well to squared detectors or sampling matrices. Cartesian grid sampling provides a different density of nodes in sectors. Zernike polynomials are a complete set of orthogonal polynomials defined on a unit disk often…
Fecha:	2011-02-21
Recurso:	RUA Docencia

Recurso libre

Number of discernible colors for color-deficient observers estimated from the MacAdam limits
Perales Romero, Esther - Martínez Verdú, Francisco Miguel - Maciel Linhares, João Manuel - Cardoso Nascimento, Sérgio Miguel

Formato:	info:eu-repo/semantics/article
Enlaces:	We estimated the number of colors perceived by color normal and color-deficient observers when looking at the theoretic limits of object-color stimuli. These limits, the optimal color stimuli, were computed for a color normal observer and CIE standard illuminant D65,…
Fecha:	2011-09-20
Recurso:	RUA Docencia

Recurso libre

10.

Overmodulation control in the optimization of a H-PDLC device with ethyl eosin as dye
Ortuño Sánchez, Manuel - Riquelme Morell, Marina - Gallego Rico, Sergi - Márquez Ruiz, Andrés - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	The response of a H-PDLC device is improved by means of a two-step method. First, component optimization—initiator system, crosslinker, and cosolvent—enables the diffraction efficiency of the hologram to be maximized. Second, the use of N-methyl-2-pyrrolidone in combination with N-vinyl-2-pyrrolidone prevents…
Fecha:	2013-12-04
Recurso:	RUA Docencia

Recurso libre

11.

Fixation-free bleached silver halide transmission holograms recorded on Slavich PFG-01 red sensitive plates
Neipp López, Cristian - Beronich, Emiliano - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	Bleaching is one of the most widely used techniques in the production of phase holograms of high quality on photographic emulsion, particularly in rehalogenating techniques without a fixation step. These techniques were very well understood when Agfa 8E75 HD emulsion…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

12.

Tensorial split-field finite-difference time-domain approach for second- and third-order nonlinear materials
Francés Monllor, Jorge - Tervo, Jani - Márquez Ruiz, Andrés

Formato:	info:eu-repo/semantics/article
Enlaces:	The split-field finite-difference time-domain (SF-FDTD) method for one-dimensionally periodic structures is extended to include the coefficient-tensor description of second- and third-order nonlinear-optical media. A set of nonlinear equations related to the split-field values of the electric field is established. An…
Fecha:	2013-09-06
Recurso:	RUA Docencia

Recurso libre

13.

Transformation of wavefront aberrations of holographic lenses for a general position of the exit pupil
Beléndez Vázquez, Augusto - Carretero López, Luis - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	Equations are derived for determining third-order wavefront aberrations in the plane of the exit pupil from the known aberration in the plane of a holographic lens. Using the transformation equations of wavefront aberration when the plane of the exit pupil…
Fecha:	2009-01-30
Recurso:	RUA Docencia

Recurso libre

14.

Model for analyzing the effects of processing on recording material in thick holograms
Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	A new model to describe the influences of chemical processing on thick holograms is presented. The model is based on three hypotheses about the behaviour of holographic recording material during processing. Thickness variations and shear-type effects that are due to…
Fecha:	2009-01-22
Recurso:	RUA Docencia

Recurso libre

15.

Thick phase holographic gratings recorded on BB-640 and PFG-01 silver halide materials
Neipp López, Cristian - Márquez Ruiz, Andrés - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	Photographic emulsions are still widely used to record holographic optical elements. In particular, if high diffraction efficiencies are needed, phase volume holograms are preferably recorded on these emulsions. Two particular techniques producing high-quality volume phase holograms are fixation-free rehalogenating bleaching…
Fecha:	2009-01-30
Recurso:	RUA Docencia

Recurso libre

16.

Birefringence of cellotape: Jones representation and experimental analysis
Beléndez Vázquez, Augusto - Fernández Varó, Elena - Francés Monllor, Jorge - Neipp López, Cristian

Formato:	info:eu-repo/semantics/article
Enlaces:	In this paper we analyze a simple experiment to study the effects of polarized light. A simple optical system composed of a polarizer, a retarder (cellotape) and an analyzer is used to study the effect on the polarization state of…
Fecha:	2010-03-22
Recurso:	RUA Docencia

Recurso libre

17.

Hybrid ternary modulation applied to multiplexing holograms in photopolymers for data page storage
Fernández Varó, Elena - Márquez Ruiz, Andrés - Gallego Rico, Sergi - Fuentes Rosillo, Rosa - García Llopis, Celia - Pascual Villalobos, Inmaculada

Formato:	info:eu-repo/semantics/article
Enlaces:	Holographic data storage is a new optical technology, which allows an important number of bits to be stored in a recording material. In this paper, holographic data pages were stored in a polyvinyl alcohol/acrylamide (AA) photopolymer layer, using a peristrophic…
Fecha:	2011-07-18
Recurso:	RUA Docencia

Recurso libre

18.

Development of a unified FDTD-FEM library for electromagnetic analysis with CPU and GPU computing
Francés Monllor, Jorge - Bleda Pérez, Sergio - Gallego Rico, Sergi - Neipp López, Cristian - Márquez Ruiz, Andrés - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	The present paper describes an optimized C++ library for the study of electromagnetics. The implementation is based on the Finite-Difference Time-Domain method for transient analysis, and the Finite Element Method for electrostatics. Both methods share the same core and are…
Fecha:	2013-05-07
Recurso:	RUA Docencia

Recurso libre

19.

First-harmonic diffusion-based model applied to a polyvinyl-alcohol–acrylamide-based photopolymer
Neipp López, Cristian - Gallego Rico, Sergi - Ortuño Sánchez, Manuel - Márquez Ruiz, Andrés - Álvarez López, Mariela Lázara - Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada

Formato:	info:eu-repo/semantics/article
Enlaces:	The photopolymerization diffusion models give accurate comprehension of the mechanism of hologram formation inside photopolymer materials. Although several models have been proposed, these models share the common assumption that there is an interplay between the processes of monomer polymerization and…
Fecha:	2009-01-22
Recurso:	RUA Docencia

Recurso libre

20.

Temporal response and first order volume changes during grating formation in photopolymers
Kelly, John V. - Gleeson, Michael R. - Close, Ciara E. - O'Neill, Feidhlim T. - Sheridan, John T. - Gallego Rico, Sergi - Neipp López, Cristian

Formato:	info:eu-repo/semantics/article
Enlaces:	We examine the evolution of the refractive index modulation when recording gratings in an acrylamide based photopolymer. A nonlocal diffusion model is used to predict theoretically the grating evolution. The model has been developed to account for both nonlocal spatial…
Fecha:	2009-02-13
Recurso:	RUA Docencia