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New paper in OLEN with a technique to generate vector beams


OLENA new publication of our team is available at the journal Optics & Lasers in Engineering, entitled Efficient on-axis engineering of optical vector modes.

In this work we present a method for the efficient experimental generation of arbitrary polarized vector beam modes. The optical system employs two LCOS-SLMs in a common path architecture, avoiding the use of beam-splitters.

We apply a recently proposed random technique to encode complex amplitude values. This encoding technique reconstructs the complex function on-axis, thus avoiding incorporating carrier phases. We demonstrate arbitrary scalar modes encoded onto orthogonal polarization components, whose superposition results in a vector beam mode.


Categories: Publications, Research Tags:

Sábado, 28 de septiembre de 2019 Sin comentarios

Special Section in Optical Engineering about Spatial Light Modulators


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. OE-SLMs

 


Miércoles, 14 de agosto de 2019 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!

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Categories: Research, Thesis Tags:

Sábado, 20 de julio de 2019 Sin comentarios

Pascuala García, María del Mar Sánchez and David Marco attend the Bienal de Física by RSEF


BienalPascuala García, María del Mar Sánchez, and David Marco attended the Bienal de Física, the biannual Spanish meeting of Physics, organized in Zaragoza by the Spanish Royal Physics Society(RSEF) (link)

David presented the poster entitled “Parallel generation of vortex beams with a 2D optical triplicator geometric phase design” in the Symposium of Quantum Optics (see here the related publication). And Pascuala presented the flash talk entitled “Highly efficient generation of arbitrary vector beams” in the Symposium of Applied Photonics (see here the related publication).

Pascuala also organized and chaired the session of Women in Physics, where María del Mar gave a talk on the activity promoting women in STEM entitled “Jornadas La Ciencia tiene nombre de Mujer de la Universidad Miguel Hernández”.

 

 


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.

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Domingo, 7 de julio de 2019 Sin comentarios

New paper in Optics Letters on breaking the Nyquist limit for diffractive lenses with high phase modulation displays


OL FIGWe 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.


Jueves, 27 de junio de 2019 Sin comentarios

Carlos Hernandez seminar about Ultrafast Structured Laser Pulses


Carlos Hernandez2One 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.


Categories: Research Tags:

Viernes, 17 de mayo 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

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