Search

Your search keyword '"Ramírez, Manuel G."' showing total 39 results
Start Over Author "Ramírez, Manuel G."
39 results on '"Ramírez, Manuel G."'

4. High-performance liquid chromatography and UV-visible measurements to optimize the storage of volume holograms in hydrogels

Author

Berramdane, Kheloud, primary, Ramírez, Manuel G., additional, Lucio, Maria Isabel, additional, Bañuls, Maria Jose, additional, Maquieira, Angel, additional, Cárdenas, Daniel, additional, Nieto-Rodríguez, Belén, additional, Morales-Vidal, Marta, additional, Ortuño, Manuel, additional, and Pascual, Inmaculada, additional

Published
2023
Full Text
View/download PDF

21. Storage Optimization of Transmission Holographic Gratings in Photohydrogels

Author

Berramdane, Kheloud, Lucío, María Isabel, Ramírez, Manuel G., Navarro-Fuster, Víctor, Bañuls, María-José, Maquieira, Ángel, Morales-Vidal, Marta, Beléndez, Augusto, and Pascual, Inmaculada

Abstract

The development and optimization of holographic materials represent a great challenge today. These materials must be synthesized according to the characteristics that are desirable in photonic devices whose application is the object of investigation. In certain holographic sensors and biosensors, it is essential that the recording material be stable in liquid media. Furthermore, the holographic gratings stored in them must have temporal and structural stability, so that they can act as transducers of the analytical signal. Therefore, it is essential to optimize its storage in terms of the chemical composition of the material and the optical parameters of recording. This work focuses on the study of the storage optimization of unslanted transmission volume phase holograms in photohydrogels based on acrylamide and N,N’-methylenebis(acrylamide). Hydrogel matrices, also composed of acrylamide and N,N’-methylenebis(acrylamide), with different degrees of cross-linking were used and analyzed by scanning electron microscopy and UV–visible spectroscopy. The best results in terms of diffraction efficiency were reached for hydrogel matrices with an acrylamide/N,N’-methylenebis(acrylamide) molar ratio between 19.9 and 26. This relationship was also optimized in the incubator solution used to incorporate the components necessary for the formation of the holograms in the hydrogel matrices. The maximum diffraction efficiency, about 35%, was achieved when using an incubation solution with an acrylamide/N,N’-methylenebis(acrylamide) molar ratio of 4.35. The influence of the physical thickness of the hydrogel layers, the intensity, and the exposure time on the diffraction efficiency was also investigated and optimized. In addition, the behavior of the hologram was analyzed after a washing stage with PBST. A simple model that considered the effects of bending and attenuation of holographic gratings was proposed and used to obtain the optical parameters of the holograms.

Published
2024
Full Text
View/download PDF

28. Holographic Lenses in an Environment-Friendly Photopolymer.

Author

Lloret, Tomás, Navarro-Fuster, Víctor, Ramírez, Manuel G., Ortuño, Manuel, Neipp, Cristian, Beléndez, Augusto, and Pascual, Inmaculada

Subjects
HOLOGRAPHIC gratings, PHOTOPOLYMERS, PHASE transitions, IMAGE processing, IMAGE quality analysis, WAVELENGTHS
Abstract

In this paper, we theoretically and experimentally evaluated the quality of volume phase transmission lenses stored in an environmentally friendly photopolymer. Holographic lenses (HLs) were obtained using symmetrical and asymmetrical experimental setups with the same positive and negative focal length and pupil diameter. The image quality was evaluated from the calculation of the modulation transfer function (MTF) by capturing the point spread function (PSF) with a charge-coupled device (CCD). A maximum frequency of 14 L/mm, reaching an MTF value of 0.1, was obtained for a negative asymmetrically recorded HL, evaluated at 473 nm wavelength. A theoretical study of aberrations was carried out to qualitatively evaluate the experimental results obtained. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

35. Improved performance of perylenediimide-based lasers

Author

Ramírez, Manuel G., primary, Morales-Vidal, Marta, additional, Navarro-Fuster, Víctor, additional, Boj, Pedro G., additional, Quintana, José A., additional, Villalvilla, José M., additional, Retolaza, Aritz, additional, Merino, Santos, additional, and Díaz-García, María A., additional

Published
2013
Full Text
View/download PDF

38. LED-Cured Reflection Gratings Stored in an Acrylate-Based Photopolymer.

Author

Ramírez, Manuel G., Sirvent, Daniel, Morales-Vidal, Marta, Ortuño, Manuel, Martínez-Guardiola, Francisco J., Francés, Jorge, and Pascual, Inmaculada

Subjects
*OPTICAL elements, *REFLECTIONS, *HOLOGRAPHY, *PHOTOPOLYMERS, *HOLOGRAPHIC gratings, *FIREPLACES, *ACRYLATES
Abstract

The storage of volume holographic reflection gratings in low-toxicity photopolymers represents a challenge at present since they can be used in many important applications such as biosensors and holographic optical elements. In this context, an acrylate-based photopolymer developed in our research group was employed to study the recording of unslanted holographic reflection gratings at high spatial frequencies. The optimal preparation conditions of the photopolymer layers were determinated. The diffraction efficiencies are measured in both recording and curing stage and a comparative study of these values was realized. In addition, a theoretical study using Kogelnik's coupled wave theory was carried out with the aim of understanding the diffraction efficiency behaviour of both processes. In this work, a maximum diffraction efficiency of 14.1% was reached after a curing process in 150 µm layers at a recording wavelength of 488 nm. This value represents a good result compared to that reported in the literature and opens the way to reflection mode holography research using low-toxicity material. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

39. Influence of Tert-Butylthiol and Tetrahydrofuran on the Holographic Characteristics of a Polymer Dispersed Liquid Crystal: A Research Line Toward a Specific Sensor for Natural Gas and Liquefied Petroleum Gas.

Author

Mora, María P., Ramírez, Manuel G., Brocal, Francisco, Ortuño, Manuel, Beléndez, Augusto, and Pascual, Inmaculada

Subjects
*TETRAHYDROFURAN, *POLYMERS, *DETECTORS, *NATURAL gas, *LIQUEFIED petroleum gas
Abstract

Tert-Butylthiol (TBT) and tetrahydrothiophene (THT) are odorant substances added to natural gas and liquefied petroleum gas to help their detection by the human smell. In this research, TBT and THT are incorporated into a holographic polymer-dispersed liquid crystal and their influence in the main holographic characteristics of the photopolymer are studied in order to open the way towards the design of a holographic sensor to detect natural gas and liquefied petroleum gas. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results