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New paper in Optics Express about a geometric phase vortex triplicator grating


REDWe published a new paper in Optics Express entitled Optimal triplicator design applied to a geometric phase vortex grating. It shows a liquid-crystal diffraction grating based on the optimal triplicator design fabricated as a geometric phase element. We analyze the polarization properties of this special diffraction grating and then use embedded spiral phases to design geometric phase vortex diffraction gratings. The fabrication of a two-dimensional version of such a design is demonstrated using a micro-patterned half-wave retarder, where the phase distribution is encoded as the orientation of the fast axis of the retarder.

This proof-of-concept element is made of liquid crystal on BK7 substrate where the orientation of the LC is controlled via photoalignment, using a commercially available fabrication facility. Experimental results demonstrate the parallel generation of vortex beams with different topological charge and different states of polarization.

This work is part of the PhD Thesis of David Marco, and it has been done in collaboration with our friends Aarón Cofré and Asticio Vargas, from Universidad de La Frontera, Temuco, Chile.


Categories: Projects, Publications, Research, Thesis Tags:

Lunes, 6 de mayo de 2019 Sin comentarios

New paper in J. Opt. Soc. Am. B about the colors of a tunable q-plate


DzexHWoW0AAiN98Our new paper in Journal of the Optical Society of America B is entitled Using birefringence colors to evaluate a tunable liquid-crystal q-plate. Here we show a tunable liquid-crystal commercial -plate from the company Arcoptix, operative in the visible and near-IR range. We study its spectral and color birefringence properties under broadband illumination.

We first characterize the spectral retardance function of the device in a wide range from 400 to 1600 nm and determine how it changes upon applied voltage.

Then we evaluate the color transmission characteristics when inserting the -plate between crossed and parallel linear polarizers. These color properties agree with the trajectory in the CIExy chromaticity diagram as the applied voltage changes.

Finally, we demonstrate that a simple visual inspection of the transmitted birefringence color perceived when placing the -plate between crossed polarizers can be used to obtain a rapid estimation of the -plate retardance at given wavelength ranges.

This work is the first paper of the PhD Thesis of David Marco.


Categories: Projects, Publications, Research, Students, Thesis Tags:

Miércoles, 13 de febrero de 2019 Sin comentarios

Julio César Quiceno, from Universidad del Valle, Cali, joins TecnOpto


Dyz6KvlU8AAYqsiJulio César Quiceno, from Universidad del Valle, Cali, Colombia, will be visiting researcher at TecnOpto for a period of six months.

We will be working together in new projects related to vector beams.

Welcome to Elche!

 


Miércoles, 13 de febrero de 2019 Sin comentarios

New paper in Optics Express about Guoy phase effects on the propagation of vector beams


GuoyOur new paper in Optics Express entitled Gouy phase effects on propagation of pure and hybrid vector beams reports a theoretical simplified model and experimental analysis of the Gouy phase effects on vector beams. Experimental results at various axial planes, before and past the focus, are obtained by using a simplified liquid-crystal spatial light modulator-based optical system that allows the easy generation of these beams. Furthermore, a new alternative optical set-up that is devoid of moving elements is demonstrated, which simplifies this study.

We experimentally verify the differences between pure and hybrid vector beams upon propagation. While the first ones remain stable, hybrid vector beams show Gouy phase effects that demonstrate an optical activity where the local polarization states rotate by an angle that depends on the propagation distance.

This study has been conducted in collaboration with our friends at San Diego State University, Prof. Jeffrey A. Davis and Prof. Don M. Cottrell.


Martes, 29 de enero de 2019 Sin comentarios

New paper in Optical Engineering about a holographic projection system


OEng2A new paper of ours is published in the journal Optical Engineering entitled Holographic projection system with programmable control of state of polarization, focus plane, and size of the reconstruction

This work presents a holographic projection system based on the encoding of computer-generated holograms onto a spatial light modulator. We show how the size, location, and polarization state of the output can be controlled completely electronically, without physically moving any element in the system. And we show that the system is capable to produce optical logical operations by superimposing two different images encoded onto orthogonal polarization states.

The work has been done with our friends at the Department of Physics at San Diego State University.

 


Jueves, 27 de diciembre de 2018 Sin comentarios

Prof. Asticio Vargas visits TecnOPTO Lab


Asticio2During the last two weeks we had the pleasure of receiving our friend Asticio Vargas, from Departamento de Ciencias Físicas, Universidad de La Frontera, Temuco, Chile.

We have been advancing in new experiments and new projects. The fruitful UMH-UFRO collaboration continues in good shape.


Categories: Collaborators, International, Projects Tags:

Viernes, 21 de diciembre de 2018 Sin comentarios

Published the SPIE proceedings of our presentations at SPIE Optics & Photonics 2018


SPIEMaría M. Sánchez-López and Ignacio Moreno attended the meeting SPIE Optics and Photonics 2018, held in San Diego (USA) in August from 19th to 23th.Logo

Maria participated in the conference “Laser Beam Shaping XVIII” where she presented the talk entitled Extending the use of commercial Q-plates for the generation of high-order and hybrid vector beams.

Ignacio participated in the conference “Optics Education and Outreach V”, where he delivered the invited talk The first International Day of Light in Spain.

Click on the titles to go the corresponding papers and presentations.

The picture shows us with our friend Andres Márquez, from Universidad de Alicante.

 


Miércoles, 15 de agosto de 2018 Sin comentarios

New paper in Optics & Lasers in Engineering with a geometric phase lens based system to analyze vector beams


VortexWe published a new paper in Optics & Lasers in Engineering entitled Geometrical-phase lens based optical system for the spin-splitting of vector beams

In this work we combine a geometric phase lens and a telescope system to produce an optical system with two polarization controlled real foci with equal magnification. And we apply it to characterize vortex beams and vector beams, splitting longitudinally the circular polarization components and focusing them into different axial planes.

This work was develop din collaboration with our friends Asticio Vargas and Fabián Torres-Ruiz, from Universidad de La Frontera, Temuco (Chile). And it is part of the PhD Thesis of Aarón Cofré.


Sábado, 14 de julio de 2018 Sin comentarios

Santiago López presents his Final Degree Project for Telecommunications Degree on a system to generate phase-only holograms with new high resolution displays


SantiagoOn July 9th, 2018, Santiago López, student of the Grade of Telecommunications Engineering, defended his final degree project entitled Caracterización de moduladores de cristal líquido para la generación de hologramas de fase y su optimización.

In this work, Santiago developed a characterization of the phase properties of some new displays acquired at the TecnOPTO Lab, and developed new methods and designs to generate phase-only holograms with them.

The project, supervised by Ignacio Moreno, received the maximum qualification


Categories: Education, Projects, Research, Students Tags:

Martes, 10 de julio de 2018 Sin comentarios

New paper on Optics Letters with a design for an achromatic retarder system with tunable retardance


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We published a new paper in Optics Letters entitled Achromatic linear retarder with tunable retardance.

In this work we present a universal design and proof-of-concept of a tunable linear retarder of uniform wavelength response in a broad spectral range. It consists of two half-wave retarders (HWR) between two quarter-wave retarders (QWRs), where the uniform retardance can be tuned continuously by simply rotating one of the HWRs. A proof-of-concept of this design is built by using commercially available Fresnel rhomb retarders that provide retardation with almost wavelength uniformity in the visible and near infrared from 450 to 1550 nm. The system is experimentally demonstrated to control the state of polarization of a super-continuum laser.

The work has been developed in collaboration with Asticio Vargas, from Universidad de la Frontera, Chile. And it is part of the PhD thesis of Abdelghafour Messaadi.


Sábado, 7 de julio de 2018 Sin comentarios