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Aproximadamente 41 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

Optical surface reconstruction technique through combination of zonal and modal fitting
Espinosa Tomás, Julián - Mas Candela, David - Pérez Rodríguez, Jorge - Illueca Contri, Carlos

Formato:	info:eu-repo/semantics/article
Enlaces:	Videokeratometers and Scheimpflug cameras permit accurate estimation of corneal surfaces. From height data it is possible to adjust analytical surfaces that will be later used for aberration calculation. Zernike polynomials are often used as adjusting polynomials, but they have shown…
Fecha:	2010-05-03
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

Copying low spatial frequency holograms in silver halide emulsions: the influence of the bleach bath
Márquez Ruiz, Andrés - Pascual Villalobos, Inmaculada - Fimia Gil, Antonio - Beléndez Vázquez, Augusto - Campos Coloma, Juan - Yzuel Giménez, María Josefa

Formato:	info:eu-repo/semantics/article
Enlaces:	We present an available and low cost technique for the production of binary-phase diffractive optical elements designed by digital methods. We produce binary-amplitude holograms making use of a high-resolution graphic device. They are used as binary masks which are copied…
Fecha:	2009-05-20
Recurso:	RUA Docencia

Recurso libre

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

Colorimetric and spectral evaluation of the optical anisotropy of metallic and pearlescent samples
Chorro Calderón, Elísabet - Perales Romero, Esther - Martínez Verdú, Francisco Miguel - Campos Acosta, Joaquín - Pons Aglio, Alicia

Formato:	info:eu-repo/semantics/article
Enlaces:	The visual and optical anisotropies of metallic and pearlescent samples have been evaluated using a multi-gonio-spectrophotometer and by adapting a gonio-template over the instrument aperture for measuring the relative spectral reflectance factor when the sample is rotated around an axis…
Fecha:	2010-02-04
Recurso:	RUA Docencia

Recurso libre

Copying low spatial frequency diffraction gratings in photopolymer as phase holograms
Pascual Villalobos, Inmaculada - Márquez Ruiz, Andrés - Beléndez Vázquez, Augusto - Fimia Gil, Antonio - Campos Coloma, Juan - Yzuel Giménez, María Josefa

Formato:	info:eu-repo/semantics/article
Enlaces:	Photopolymers are studied as holographic recording materials for recording computer-generated phase holograms. The recording was performed using a holographic copying process, in which the master is produced by means of a high resolution graphic device. To our knowledge it is…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

Angular responses of the first diffracted order in over-modulated volume diffraction gratings
Neipp López, Cristian - Álvarez López, Mariela Lázara - Gallego Rico, Sergi - Ortuño Sánchez, Manuel - Sheridan, John T. - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	Kogelnik's coupled-wave (CW) theory has been used for decades to predict the diffraction efficiency of volume diffraction gratings. Although this theory has been applied with success to volume diffraction gratings recorded under a great variety of experimental conditions, its predictions…
Fecha:	2009-02-03
Recurso:	RUA Docencia

Recurso libre

The computation and statistical analysis of aberrational diffraction patterns in holographic optical elements
Carretero López, Luis - Fimia Gil, Antonio - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	Three numerical methods for calculating the point spread function for holographic optical elements in the presence of aberrations are analyzed. The starting point for the analytical formulation of the diffraction theory of aberrations for holographic optical elements is the Fresnel-Kirchhoff…
Fecha:	2009-01-30
Recurso:	RUA Docencia

Recurso libre

10.

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

11.

High-efficiency silver-halide sensitized gelatin holograms with low absorption and scatter
Beléndez Vázquez, Augusto - Neipp López, Cristian - Flores, Marcos - Pascual Villalobos, Inmaculada

Formato:	info:eu-repo/semantics/article
Enlaces:	We report for the first time the results of a comparative performance study of silver-halide sensitized gelatin (SHSG) holograms recorded in the familiar Agfa 8E75 HD plates and the new BB-640 plates manufactured by Holographic Recording Technologies. High diffraction efficiency…
Fecha:	2009-02-03
Recurso:	RUA Docencia

Recurso libre

12.

The influence of the procedure on the dynamic range of bleached silver halide emulsions
Neipp López, Cristian - Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada

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. Using Kogelnik's coupled-wave theory we shall obtain information about the…
Fecha:	2009-02-03
Recurso:	RUA Docencia

Recurso libre

13.

Statistical model for noise gratings recorded in volume holograms
Carretero López, Luis - Fimia Gil, Antonio - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	A statistical model is used to study the formation of noise gratings in holograms and the mechanism that causes radiation scattering in them. The theoretical model presented describes noise scattering in terms of diffraction due to the high number of…
Fecha:	2009-02-03
Recurso:	RUA Docencia

Recurso libre

14.

Nonlinear response of photopolymers for holography: copolymerization process
Fimia Gil, Antonio - Carretero López, Luis - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	A model is proposed which allows us to obtain the diffraction efficiency of photopolymeric materials with a nonlinear response to the refraction index, using the equations on the evolution of copolymerization reactions as a base. The photochemical material being analysed…
Fecha:	2009-02-03
Recurso:	RUA Docencia

Recurso libre

15.

Fresnel diffraction in a theoretical eye: a fractional Fourier transform approach
Pons Moreno, Álvaro Máximo - Lorente Velázquez, Amalia - Illueca Contri, Carlos - Mas Candela, David - Artigas Verde, José María

Formato:	info:eu-repo/semantics/article
Enlaces:	In this work, we have applied the fractional Fourier transform to obtain the Fresnel diffraction patterns in a theoretical eye. The FRT approach to Fresnel diffraction is easily implemented in a Gullstrand-Emsley theoretical eye, and it allows us to obtain…
Fecha:	2007-10-16
Recurso:	RUA Docencia

Recurso libre

16.

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

17.

Computation and visualization of the MacAdam limits for any lightness, hue angle, and light source
Martínez Verdú, Francisco Miguel - Perales Romero, Esther - Chorro Calderón, Elísabet - Fez Saiz, Dolores de - Viqueira Pérez, Valentín - Gilabert Pérez, Eduardo

Formato:	info:eu-repo/semantics/article
Enlaces:	We present a systematic algorithm capable of searching for optimal colors for any lightness L* (between 0 and 100), any illuminant (D65, F2, F7, F11, etc.), and any light source reported by CIE. Color solids are graphed in some color…
Fecha:	2007-07-11
Recurso:	RUA Docencia

Recurso libre

18.

Custom designed dynamic videokeratometer
Mas Candela, David - Kowalska, Malgorzata A. - Espinosa Tomás, Julián - Kasprzak, Henryk T.

Formato:	info:eu-repo/semantics/article
Enlaces:	The human eye is a complex dynamic system that undergoes fine rotations and deformations. Usually information about the eye globe deformation and micromovements are averaged and lost when using commercial measuring devices, although they provide important information about the eye’s…
Fecha:	2010-02-25
Recurso:	RUA Docencia

Recurso libre

19.

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

20.

Influence of the gaze-stabilizing eye movements on the quality of the retinal image of the human eye
Pons Moreno, Álvaro Máximo - Lorente Velázquez, Amalia - Illueca Contri, Carlos - Artigas Verde, José María - Felipe Marcet, Adelina

Formato:	info:eu-repo/semantics/article
Enlaces:	In this work we have studied the influence of the gaze stabilizing movements of the eye on the quality of the retinal image of the human eye obtained by double pass methods. The results obtained agree with the expected differences…
Fecha:	2007-10-16
Recurso:	RUA Docencia

Recurso libre

21.

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

22.

Silver halide sensitized gelatin holograms in Slavich PFG-01 red-sensitive emulsion
Beléndez Vázquez, Augusto - Neipp López, Cristian - Pascual Villalobos, Inmaculada

Formato:	info:eu-repo/semantics/article
Enlaces:	Silver halide sensitized gelatin (SHSG) is an interesting technique for the production of holographic optical elements. It combines the high sensitivity of photographic emulsions with the well-known low scattering and high diffraction efficiency corresponding to dichromated gelatin. In this paper…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

23.

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

24.

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

25.

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

26.

Corneal aberrometric and refractive performance of 2 intrastromal corneal ring segment models in early and moderate ectatic disease
Piñero Llorens, David Pablo - Alió y Sanz, Jorge L. - El Kady, Bassam - Pascual Villalobos, Inmaculada

Formato:	info:eu-repo/semantics/article
Enlaces:	Purpose: To evaluate and compare visual, refractive, and corneal aberrometric outcomes after implantation of 2 types of intrastromal corneal ring segments (ICRS) in eyes with early to moderate ectatic disease. Settings: Vissum Corporation-Instituto Oftalmológico de Alicante, Alicante, Spain. Methods: This…
Fecha:	2010-02-15
Recurso:	RUA Docencia

Recurso libre

27.

Holographic optical elements in the presence of spherical aberration and focus error: some remarks on imaging quality
Beléndez Vázquez, Augusto - Carretero López, Luis - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	When aberrations are small, it is possible to use wave aberration variance to obtain the position of the best image plane in both conventional and holographic optical systems. However, when aberrations increase, this measurement is not sufficient and it does…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

28.

High-efficiency volume holograms recording on acrylamide and N,N'methylene-bis-acrylamide photopolymer with pulsed laser
Gallego Rico, Sergi - Ortuño Sánchez, Manuel - García Llopis, Celia - Neipp López, Cristian - Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada

Formato:	info:eu-repo/semantics/article
Enlaces:	In order to achieve a better understanding of the mechanisms of hologram formation and higher diffraction efficiencies in volume gratings stored in acrylamide based photopolymers, a crosslinker (N,N'methylene-bis-acrylamide) has been incorporated in the photopolymer to record holograms by pulsed laser…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

29.

Effect of the glass substrate on the efficiency of the different orders that propagate in a transmission sinusoidal diffraction grating
Neipp López, Cristian - Sheridan, John T. - Márquez Ruiz, Andrés - Gallego Rico, Sergi - Ortuño Sánchez, Manuel - Beléndez Vázquez, Augusto - Pascual Villalobos, Inmaculada

Formato:	info:eu-repo/semantics/article
Enlaces:	In this work we study the effect of the glass substrate on the efficiencies of the different orders that propagate inside a transmission sinusoidal diffraction grating. Holographic optical elements are usually recorded on a photosensitive medium deposited on to a…
Fecha:	2009-02-02
Recurso:	RUA Docencia

Recurso libre

30.

Complete algorithm for the calculation light patterns inside the ocular media
Pérez Rodríguez, Jorge - Mas Candela, David - Illueca Contri, Carlos - Miret Marí, Juan José - Vázquez Ferri, Carmen - Hernández Poveda, Consuelo

Formato:	info:eu-repo/semantics/article
Enlaces:	Realistic mathematical models are of great importance for studying the optical performance of the human eye. Light propagation algorithms provide robust methods to calculate field distributions inside a homogeneous medium, and thus they can be applied to the study of…
Fecha:	2007-10-08
Recurso:	RUA Docencia

Recurso libre

31.

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

32.

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

33.

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

34.

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

35.

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

36.

Noise gratings in thick-phase holographic lenses
Beléndez Vázquez, Augusto - Fuentes Rosillo, Rosa - Fimia Gil, Antonio

Formato:	info:eu-repo/semantics/article
Enlaces:	An experimental analysis of noise gratings in holographic lenses is presented. Lenses are recorded as thick-phase holograms in bleached silver halide emulsion. The authors calculated noise grating efficiency by using the diffraction efficiency in points across a lens diameter. They…
Fecha:	2009-01-30
Recurso:	RUA Docencia

Recurso libre

37.

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

38.

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

39.

Mixed phase-amplitude holographic gratings recorded in bleached silver halide materials
Neipp López, Cristian - Pascual Villalobos, Carolina - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	The coupled wave theory of Kogelnik has given a well-established basis for the comprehension of how light propagates inside a volume hologram. This theory gives a good approximation for the diffraction efficiency of both volume phase holograms and volume absorption…
Fecha:	2009-01-30
Recurso:	RUA Docencia

Recurso libre

40.

Comparative study of bleaches applied to BB-640 plates
Neipp López, Cristian - Condeza, Shirley - Campos, Ana María - Pascual Villalobos, Inmaculada - Beléndez Vázquez, Augusto

Formato:	info:eu-repo/semantics/article
Enlaces:	The use of bleaching techniques is perhaps one of the most popular methods of creating phase holograms from holographic emulsions. In this paper we will study the influence of the different experimental conditions on the refractive index modulation created inside…
Fecha:	2009-01-30
Recurso:	RUA Docencia

Recurso libre

41.

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