Grupo de Tecnologías Ópticas y Optoelectrónicas

Our new publication is available in Optics & Lasers in Engineering, entitled Diffraction efficiency of stepped gratings using high phase-modulation spatial light modulators.

We study the diffraction efficiency of linear phase (blazed) diffraction gratings displayed onto SLMs that exhibit a large phase modulation range, reaching a maximum phase modulation of 8pi or 10pi radians. We analyse these effects for their important implications in the Nyquist limit for diffractive elements

The paper has been done in collaboration with our friends at San Diego State University.

A special section on Spatial Light Modulators (SLMs) – Devices and Applications will be published in the journal Optical Engineering. Ignacio Moreno and María Del Mar Sanchez-Lopez are Guest Editors of this special section of the journal, together with Prof. Andrew Forbes and Prof. Yoshio Hayasaky.

The following link leads to the journal Call for Papers.

The deadline for submitting papers is October 15th, 2019. See here the flyer of the OE special section on SLMs. 

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.

We published a new paper in Optics Letters entitled Encoding lenses with focal lengths lower than the Nyquist limit using high phase-modulation displays. In this work we show that focal lengths much lower than the classical Nyquist limit can be encoded onto spatial light modulators having a large phase-dynamic range.

Experimental results are included with a display showing 10π phase modulation reducing the Nyquist limit by a factor of about 1/10. We used a  Hamamatsu reflective LCoS device designed for use in the near infra-red (NIR) range, but operated with visible light in order to achieve such large modulation regimes.

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

We had the visit to UMH of Yann Amouroux, OSA Europe Director, in the frame of his intense tour in Spain to visit Optics & Photonics centers.

Good interaction to contribute to the SEDOPTICA-OSA collaboration, and also with TecnOPTO and other photonics colleagues at UMH.

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.