One day after the International Day of Light, Dr. Carlos Hernandez Garcia from USAL gave a seminar at TecnOPTO about Ultrafast Structured Laser Pulses – Extreme-Ultraviolet Vortex Beams Carrying Spin and Orbital Angular Momentum.
A great talk and a great discussion after the talk.
In May 16th 2019, we celebrated the International Day of Light. We had the visit of Dr. Carlos Hernández GarcÃa, from the Research Group in Applications of Laser and Photonics Applications (ALF-USAL) of the University of Salamanca, a recognized expert in the generation of ultra-fast structured laser pulses
He imparted an excellent talk entitled Sculpting laser pulses, where he explained the Nobel Prize in Physics 2018, awarded to Arthur Ashkin, Gérard Mourou and Donna Strickland for their breakthroughs in laser physics. The talk can be viewed on line at the following link.
This conference was organized by the Local Section of Alicante of the Royal Spanish Physics Society (RSEF), in collaboration with the Department of Physics, the Institute of Bioengineering and the Polytechnical School of UMH, and was attended by over 80 students and faculty members.
We were also supported by SPIE, that provided Women in Optics agendas!
We 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.
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 FÃsicas, 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.
MarÃa 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.