Mr. Roberto Fernández Profile

Roberto Fernández

Optics Researcher at Univ de Alicante

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Author

Publications (13)

Proceedings Article | 1 April 2020 Presentation + Paper

3-dimensional modelling of the DOEs formation in PVA/AA photopolymers

R. Fernández, S. Gallego, A. Márquez, J. Francés, C. Neipp, D. Puerto, E. Calzado, I. Pascual, A. Beléndez

Proceedings Volume 11367, 113671E (2020) https://doi.org/10.1117/12.2555692

KEYWORDS: 3D modeling, Diffractive optical elements, Axicons, Diffusion, Polymerization, Photopolymers, Liquid crystal on silicon, Lenses, Refractive index, Spatial frequencies

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Proceedings Article | 7 September 2018 Paper

Anamorphic characterization of a PA-LCoS based holographic data storage system

Francisco J. Martínez-Guardiola, Andrés Márquez, Eva Calzado, Roberto Fernández, Cristian Neipp, Manuel Ortuño, Inmaculada Pascual, Sergi Gallego

Proceedings Volume 10751, 1075112 (2018) https://doi.org/10.1117/12.2321276

KEYWORDS: Image resolution, Holographic data storage systems, CCD cameras, Error analysis, Liquid crystal on silicon, Statistical analysis, Image filtering, Binary data, Image retrieval, Beam splitters

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Proceedings Article | 24 August 2017 Paper

Diffractive lenses in biocompatible photopolymers using LCoS

Roberto Fernández, Sergi Gallego, Víctor Navarro-Fuster, Manuel Ortuño, Andrés Márquez, C. Neipp, Augusto Beléndez, Inmaculada Pascual

Proceedings Volume 10395, 103951D (2017) https://doi.org/10.1117/12.2273840

KEYWORDS: Photopolymers, Liquid crystal on silicon, Modulation, Lenses, LCDs, Spatial light modulators, Diffractive optical elements, Optical properties, Image processing, Optical recording

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The improving of the technology related to the Spatial Light Modulators (SLM), which can be used to modulate the wavefront of a light beam in many different applications in Optics and Photonics, has widespread their use in many new ways. In particular, the continue miniaturization of the pixel size let them be used as a master for Diffractive Optical Elements(DOE) recording applications. One of these displays isthe parallel-addressed liquid crystal on silicon (PA-LCoS) microdisplay, which offers easily the possibility of phase-only modulation without coupled amplitude modulation, but can be use also as an amplitude master just rotating the angles of two polarizers. Together with the DOEs, the optic recording material is also one of the crucial componentsin the system. Photoresist has been used classically for this purpose. Recently some works provide results of the incorporation of photopolymers, initially used for holographic recording, to fabricate DOEs. Among photopolymers, polyvinil alcohol/acrylamide (PVA/AA) materials have been studied firstly due to the accurate control of their optical properties and the ease of fabrication. Nevertheless, this kind of photopolymer presents a high level of toxicity due mainly to the monomer, acrylamide. In this sense, we made efforts to search alternative “green” photopolymers, one of these is called “Biophotopol”. This material presents good optical properties; although, it has two principal drawbacks: its refractive index modulation is lower than the PVA/AA one and the dye used presents very low absorption at 532 nm. In order to solve these problems for recording spherical diffractive lenses, in the present work we have explored different possibilities. On the first place, we have modified the fabrication technique of the solid layer to achieve thicker samples, on the second place, we have introduced a biocompatible crosslinker monomer. These two actions provide us a higher value of the phase modulation capability. On the third place, we have modified the dye to record DOE’s with the wavelength of 532 nm and obtain a direct comparison with the results obtained with PVA/AA materials.

Proceedings Article | 15 May 2017 Presentation + Paper

Shrinkage measurement for holographic recording materials

R. Fernández, S. Gallego, A. Márquez, J. Francés, V. Navarro Fuster, C. Neipp, M. Ortuño, A. Beléndez, I. Pascual

Proceedings Volume 10233, 102330C (2017) https://doi.org/10.1117/12.2265180

KEYWORDS: Diffraction, Holography, Photopolymers, Holographic materials, Liquid crystals, Holography applications, Nanoparticles, Molecules, Thin films, LCDs, Holograms

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Proceedings Article | 15 May 2017 Paper

Multiplexed holograms recorded in a low toxicity Biophotopol photopolymer

Víctor Navarro-Fuster, Manuel Ortuño, Sergi Gallego, Roberto Fernández, Francisco Martínez-Guardiola, Andrés Márquez, Inmaculada Pascual

Proceedings Volume 10233, 102331O (2017) https://doi.org/10.1117/12.2264903

KEYWORDS: Humidity, Argon ion lasers, Holography, Diffraction, Multiplexing, Diffraction gratings, Holograms, Toxicity, Holographic materials, Holographic optical elements, Sensors, Photonics

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Proceedings Article | 14 September 2016 Paper

Influence of the spatial frequency on the diffractive optical elements fabrication in PDLCs

R. Fernández, S. Fenoll, S. Gallego, A. Márquez, J. Francés, V. Navarro Fuster, A. Beléndez, I. Pascual

Proceedings Volume 9970, 997019 (2016) https://doi.org/10.1117/12.2236302

KEYWORDS: Spatial frequencies, Diffractive optical elements, Liquid crystals, Holography, Photopolymers, Liquid crystal on silicon, Diffraction, Diffraction gratings, Molecules, Composites

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Proceedings Article | 14 September 2016 Paper

PVA/AA photopolymers and PA-LCoS devices combined for holographic data storage

Andrés Márquez, Francisco Martínez, Roberto Fernández, Sergi Gallego, Mariela Álvarez, Inmaculada Pascual, Augusto Beléndez

Proceedings Volume 9970, 997008 (2016) https://doi.org/10.1117/12.2236113

KEYWORDS: Holography, Photopolymers, Modulation, Spatial light modulators, Binary data, Holographic data storage systems, Data storage, Liquid crystal on silicon, Phase shift keying, Polarizers

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Proceedings Article | 27 April 2016 Paper

Cylindrical diffractive lenses recorded on PVA/AA photopolymers

R. Fernández, S. Gallego, A. Márquez, V. Navarro-Fuster, J. Francés, C. Neipp, A. Beléndez, I. Pascual

Proceedings Volume 9889, 988918 (2016) https://doi.org/10.1117/12.2227076

KEYWORDS: Photopolymers, Diffractive optical elements, Lenses, Optical simulations, Holography, Liquid crystal on silicon, Cylindrical lenses, Optical recording, Data storage, Waveguides, Photopolymers, Diffractive optical elements, CCD cameras, Modulation, Refractive index, Liquids

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Proceedings Article | 9 September 2015 Paper

Study of the index matching for different photopolymers

Roberto Fernández, Sergi Gallego, Andrés Márquez, Manuel Ortuño, Stephan Marini, Inmaculada Pascual, Augusto Beléndez

Proceedings Volume 9598, 95980A (2015) https://doi.org/10.1117/12.2188349

KEYWORDS: Liquids, Photopolymers, Refractive index, Diffusion, LCDs, Diffractive optical elements, Sodium, Polymers, Polymerization, Modulation

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Proceedings Article | 19 September 2014 Paper

Influence of the photopolymer properties in the fabrication of diffractive optical elements

Sergi Gallego, Roberto Fernández, Andrés Márquez, Francisco Martínez, Cristian Neipp, Manuel Ortuño, Jorge Francés, Augusto Beléndez, Inmaculada Pascual

Proceedings Volume 9216, 921619 (2014) https://doi.org/10.1117/12.2060990

KEYWORDS: Polymers, Diffractive optical elements, Refractive index, Diffusion, Holography, Binary data, Absorption, Signal attenuation, Ions, Optical components

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Proceedings Article | 22 August 2014 Paper

Influence of a bleaching post-exposure treatment in the performance of H-PDLC devices with high electric conductivity

Manuel Ortuño, Andrés Márquez, Sergi Gallego, Roberto Fernandez, Víctor Navarro-Fuster, Augusto Beléndez, Inmaculada Pascual

Proceedings Volume 9286, 92865C (2014) https://doi.org/10.1117/12.2063540

KEYWORDS: Liquid crystals, Electro optics, Diffraction, Holography, Polymers, Diffraction gratings, Molecules, Holograms, Glasses, Ions

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Proceedings Article | 1 May 2014 Paper

Influence of the set-up on the recording of diffractive optical elements into photopolymers

S. Gallego, R. Fernández, A. Márquez, C. Neipp, A. Beléndez, I. Pascual

Proceedings Volume 9131, 91311H (2014) https://doi.org/10.1117/12.2051709

KEYWORDS: LCDs, Diffractive optical elements, Visibility, Photopolymers, Linear filtering, Modulation, Refractive index, Image filtering, Holography, Video

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Proceedings Article | 26 September 2013 Paper

Analysis of the fabrication of diffractive optical elements in photopolymers

S. Gallego, A. Márquez, R. Fernández, Á. Piera, F. Martínez-Gaurdioloa, M. Ortuño, J. Francés, A. Beléndez, I. Pascual

Proceedings Volume 8855, 88550V (2013) https://doi.org/10.1117/12.2023861

KEYWORDS: Photopolymers, Diffractive optical elements, Linear filtering, Diffusion, LCDs, Refractive index, Optical filters, Polymers, Binary data, Spatial frequencies

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Showing 5 of 13 publications

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