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Aproximadamente 22 registro(s) hasta el momento: (journal)

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Recurso libre

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

Retinal image quality assessment through a visual similarity index
Pérez Rodríguez, Jorge - Espinosa Tomás, Julián - Vázquez Ferri, Carmen - Mas Candela, David

Formato:	info:eu-repo/semantics/article
Enlaces:	Retinal image quality is commonly analyzed through parameters inherited from instrumental optics. These parameters are defined for ‘good optics’ so they are hard to translate into visual quality metrics. Instead of using point or artificial functions, we propose a quality…
Fecha:	2013-05-13
Recurso:	RUA Docencia

Recurso libre

Refractive analysis of the human cornea through propagated fields
Illueca Contri, Carlos - Mas Candela, David - Pérez Rodríguez, Jorge - Pons Moreno, Álvaro Máximo - Artigas Verde, José María

Formato:	info:eu-repo/semantics/article
Enlaces:	A new technique for analysing the optical quality of the human cornea is presented. Corneal maps are obtained through keratographies and then converted into phase maps. The propagated fields generated from this surface are plotted and studied. It is shown…
Fecha:	2007-10-16
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

Propagation and phase reconstruction of ocular wavefronts with SAR techniques
Rouarch, Jessica - Espinosa Tomás, Julián - Miret Marí, Juan José - Mas Candela, David - Pérez Rodríguez, Jorge - Illueca Contri, Carlos

Formato:	info:eu-repo/semantics/preprint
Enlaces:	In this communication, we report a new method to determine the wavefront aberration function of personalized eyes. We obtain corneal surface data and axial lengths for different eyes. With these data, we construct a diffractive model of a human eye,…
Fecha:	2008-03-06
Recurso:	RUA Docencia

Recurso libre

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

Blinking kinematics description through non-invasive measurement
Pérez Rodríguez, Jorge - Espinosa Tomás, Julián - Doménech Amigot, Begoña - Mas Candela, David - Illueca Contri, Carlos

Formato:	info:eu-repo/semantics/article
Enlaces:	Spontaneous eye blinking is a complex process, which implies the joint actions of the eyelid muscles and the eye globe. These actions provoke the eyelid closure and simultaneous eye retraction into the orbit. Recently, the authors presented a non-invasive technique…
Fecha:	2011-02-16
Recurso:	RUA Docencia

Recurso libre

Diffuse-object holograms in silver halide sensitized gelatin
Fimia Gil, Antonio - Pascual Villalobos, Inmaculada - Carretero López, Luis - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	This paper deals with diffuse-object holograms recorded in silver halide sensitized gelatin. Both the diffraction efficiency and the signal-to-noise ratio when reconstruction is done with different wavelengths are measured. The experimental results we obtained show that new theoretical models for…
Fecha:	2009-02-03
Recurso:	RUA Docencia

Recurso libre

Geometrical Optics and Riemannian Geometry
Carretero López, Luis - Mateos Álvarez, Felipe - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	The methods of differential geometry are used with the assumption that rays of light follow geodesic trajectories in a space whose metric is determined by the refraction index. Keeping this in mind, we show that these hypotheses are equivalent to…
Fecha:	2009-03-20
Recurso:	RUA Docencia

Recurso libre

10.

Axial irradiance and entropy of holographic optical elements under illumination with quasi-monochromatic light
Carretero López, Luis - Beléndez Vázquez, Augusto - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	The chromatic sensitivity of holographic optical elements for use in optical interconnect systems is quantified using an entropy merit function. The influence of broad-band illumination on axial irradiance and intensity is studied showing that the best imaging point obtained with…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

11.

Method for the characterization of hologram processing
Bányász, Istvan - Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	A novel method for the characterization of the processing of both absorption and phase holograms is proposed. Differently from the previous models, the square root of the diffraction efficiency of the processed hologram was directly related to the amplitude of…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

12.

Comparison of nonlinear characteristics of phase holograms processed by various combinations of developers and bleaching agents
Bányász, Istvan - Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	Optical densities before bleaching and final Lin curves of planewave phase holograms recorded in Agfa—Gevaert 8E75HD emulsions were measured for various combinations of developers (AAC, Pyrogallol and Catechol) and bleaching agents (R-9 and EDTA). To characterize the processing, the square…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

13.

Bleached silver halide volume holograms recorded on Slavich PFG-01 emulsion: the influence of the developer
Neipp López, Cristian - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	Bleached holograms are one of the most interesting techniques used to produce phase holograms of high quality on photographic emulsions. Of particular interest is the method of fixation-free rehalogenating bleaching. In this paper we will study the influence of the…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

14.

Stabilization of volume gratings recorded in polyvinyl alcohol-acrylamide photopolymers with diffraction efficiencies higher than 90%
Gallego Rico, Sergi - Neipp López, Cristian - Ortuño Sánchez, Manuel - Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada

Formato:	info:eu-repo/semantics/article
Enlaces:	Obtaining holographic volume gratings with high diffraction efficiencies that can be used under white light has been a serious problem for the polyvinyl alcohol-acrylamide-based photopolymers developed by other researchers. In this paper we propose to eliminate the residual monomer in…
Fecha:	2009-02-03
Recurso:	RUA Docencia

Recurso libre

15.

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

16.

Diffractive and interferometric methods to characterize photopolymers with liquid crystal molecules as holographic recording material
Gallego Rico, Sergi - Márquez Ruiz, Andrés - Ortuño Sánchez, Manuel - Francés Monllor, Jorge - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	We present two methods, interferometry at the zero spatial frequency limit and analysis of diffracted orders for very low spatial frequency gratings, to characterize photopolymers with dispersed nematic liquid crystals. These methods provide us with real time information about the…
Fecha:	2012-07-04
Recurso:	RUA Docencia

Recurso libre

17.

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

18.

Theoretical and experimental analysis of overmodulation effects in volume holograms recorded on BB-640 emulsions
Neipp López, Cristian - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	Kogelnik's coupled-wave theory has provided a well-established basis for understanding how light propagates inside a volume hologram, giving an accurate approximation of the diffraction efficiency in this type of hologram. In this paper we elaborate on some aspects of the…
Fecha:	2009-01-30
Recurso:	RUA Docencia

Recurso libre

19.

New theoretical matrix formula for intraocular lens calculation using the optimal bending factor
Fimia Gil, Antonio - Alió y Sanz, Jorge L. - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	By applying Gaussian optics we propose a new matrix formula model for intraocular lens (IOL) calculation that yields not only IOL optical power for a particular eye but also an evaluation of the bending factor of different IOL optical designs.…
Fecha:	2009-01-29
Recurso:	RUA Docencia

Recurso libre

20.

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

21.

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

22.

Some activities on educational technology innovation in Physics, optics and telecommunications
Arribas Garde, Enrique - Beléndez Vázquez, Augusto - Nájera López, Alberto - Márquez Ruiz, Andrés - Villalba Montoya, José Manuel - Gallego Rico, Sergi - Ortuño Sánchez, Manuel - Francés Monllor, Jorge - Álvarez López, Mariela Lázara - Neipp López, Cristian - Pascual Villalobos, Inmaculada

Formato:	info:eu-repo/semantics/article
Enlaces:	The use of innovative technologies in education offers new possibilities that complement classroom teaching and may also help to improve the quality of education, enabling students to actively participate in the learning process. With this in mind, in 2009 the…
Fecha:	2012-10-01
Recurso:	RUA Docencia