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David Marco defends his PhD Thesis

DMARCODavid Marco completed his PhD studies with a public defense of his PhD Thesis entitled «Design and characterization of spatial light modulator optical systems and geometrical phase elements for the generation of structured light«, supervised by María del Mar Sánchez-Lopez and Ignacio Moreno.

The Thesis has been developed at TECNIT – the Doctoral Program on Industrial and Telecommunications Technologies at UMH.

The jury for the defense was composed by Dr. Gemma Piquero, from University Complutense of Madrid, Dr. Carlos Hernández, from University of Salamanca and Dr. Carlos R. Fernández-Pousa, from UMH.




Miércoles, 1 de septiembre de 2021 Sin comentarios

New paper in Scientific Reports about generating customized depolarizated spatial light patterns

Fig SCI REPIn our recent paper in Scientific Reports entitled Customized depolarization spatial patterns with dynamic retardance functions we demonstrate a proof-of-concept of a dynamical time-dependent pixelated retarder used to emulate a controlled spatially variant depolarizing sample.

We apply an imaging Mueller polarimetric system based on a polarization camera to verify the effective depolarization effect, and the effective depolarizance results are fully described within a simple graphical approach and standard Mueller matrix decomposition methods. The technique is illustrated by means of three practical cases, including exotic structures as a spirally shaped depolarization pattern.

The work has been done in collaboration with our colleagues Angel Lizana and Juan Campos, from MIP Optilab Laboratory at the Department of Physics of Universitat Autònoma de Barcelona, in the frame of our common research project devoted to the development of advanced polarimetric systems.

This work is also part of the PhD Thesis of David Marco.

Lunes, 3 de mayo de 2021 Sin comentarios

New paper in Optics Letters about a new technique of measuring the LCOS backplane deformation

INT1A new paper is available in Optics Letters entitled Measuring the spatial deformation of a liquid-crystal on silicon display with a self-interference effect.

Here we present a simple technique to characterize the spatial non-uniformity of a LCOS-SLM, based on illuminating the display with a wavelength out of the operation range. In this situation there is a significant reflection at the output surface and a Gires–Tournois type interferometer is directly created, without any alignment requirement and insensitive to vibrations. The beam reflected at the output surface is the reference beam, while the beam reflected at the silicon backplane is modulated with the addressed gray level in order to quantitatively derive its deformation. We provide an experimental demonstration using a LCOS-SLM designed to operate in the near-infrared range but illuminated with visible light.

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

Viernes, 7 de agosto de 2020 Sin comentarios

Maria del Mar Sanchez-Lopez visits GROC-UJI

María del Mar Sánchez-López visited the Group of Optics of the University Jaume I de Castellón (GROC-UJI) to participate as a member of the jury of the Doctoral Thesis of Yessenia Jauregui Sanchez, supervised by Prof. Jesús Lancis and Prof. Enrique Tajahuerce.

Excellent work on single-pixel cameras and imaging through scattering media!


Categories: Research, Thesis Tags:

Sábado, 20 de julio de 2019 Sin comentarios

David Marco and Julio César Quiceno present their results at IONS 2019, Barcelona, June 2019

In his talk entitled «Two-dimensional geometric phase vortex grating based on the optimal triplicator design», David presented the design and characterization of a liquid-crystal geometric phase diffraction grating that generates 3×3 diffraction orders with vortex beams of different topological charges, and showed the operation of this grating as a vortex detector. These results have recently been published in Optics Express: link to the paper.

Julio César presented a poster entitled “Hybrid vector beams generated by cascaded q-plates” where he demonstrated a q-plate-based optical system capable of generating a variety of hybrid vector beams, and showed the rotation of their polarization pattern when comparing the near field and the far field captures. This optical system is more compact than those based on SLMs whilst bearing a notable degree of versatility.

They have enjoyed the interesting conferences, scientific discussions and networking opportunities of this conference hosted by the OSA student chapter at ICFO and backed by the International OSA Network of Students. Link to the conference.




Domingo, 7 de julio de 2019 Sin comentarios

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

Aarón Cofré presents his PhD Thesis on diffractive optics systems for the generation of optical vortices and structured polarized beams

AaronOn 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.




Miércoles, 11 de julio de 2018 Sin comentarios

Our former student Venancio Calero presents his PhD Thesis at FEMTO-ST Institute

VenancioOur former student Venacio Calero, presented his PhD Thesis entitled «Antenne à cristal photonique électro-optique pour la détection de fréquences électromagnétiques», supervised by María Pilar Bernal and Nadège Courjal at the FEMTO-ST Institute, in Besançon (France), on December 19th, 2017.

Ignacio Moreno attended the defense and participated as a member of the jury.



Viernes, 5 de enero de 2018 Sin comentarios

New paper in Optics Express about dual polarization split lenses

OptExpressWe published a new paper in Optics Express where we report the realization of polarization sensitive split lens configurations. We propose and demonstrate the generalization of the split lens concept to vectorial split lenses, leading to light patterns with customized intensity and state of polarization. We demonstrate how these polarization split lenses can be experimentally implemented by means of an optical system using two liquid crystal spatial light modulators, each one phase modulating one orthogonal polarization component.

The proposed technique is a simple method to generate structured light beams with polarization diversity, with potential applications in polarimetry, customized illuminators or quantum optics.

This work has been published in Optics Express, entitled Dual polarization split lenses. The work has been developed in collaboration with our friends at the Departamento de Ciencias Físicas, Universidad de la Frontera (Chile) and our friends at Departamento de Física de la Universitat Autònoma de Barcelona. This is the third paper resulting from the Thesis of the PhD student Aarón Cofré.


Martes, 19 de septiembre de 2017 Sin comentarios