Grupo de Tecnologías Ópticas y Optoelectrónicas

Our 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.

Julio 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!

Our 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.

A 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.

During 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.

Ignacio Moreno visited the University of Guanajuato, in Salamanca, Mexico, invited with the OSA Travelling Lecturer Program by the OSA Student Chapter.

In August 30th, 2018, he delivered a lecture about Digital Holography with Spatial Light Modulators.

In this talk, he introduced the principles of SLMs and some of their applications when displaying phase-only holograms  to engineering students of University of Guanajuato.

María 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.

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.

We 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.

On July 10th 2018, Aarón Cofré presented the defense of his PhD Thesis entitled Development of advanced diffractive systems for the generation of optical vortices and structured polarized beams.

The Thesis has been supervised by Ignacio Moreno and Asticio Vargas, and included various experimental studies on how to generate optical vortices and vector beams.

The results of the thesis resulted in four articles published in the journals European Journal of Physics, Optics & Lasers Technology, Optics Express and Optics & Lasers in Engineering respectively.

In the picture, Aarón with the supervisors and the members of the jury.

On 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