New paper in Optical Engineering analyzing the random multiplexing approach in modern LCOS SLMs

A new paper is now published in Optical Engineering entitled Multiplexing onto a spatial light modulator using random binary patterns. In this paper we analyze the random approach for encoding a variety of independent outputs from a multiplexed computer-generated diffractive element displayed on a SLM. Although the technique was demonstrated years ago, nowadays it can be applied with high-resolution SLMs with a very large number of pixels, thus allowing for a larger number of multiplexed functions without significant degradation. Nevertheless, we show that the technique is quite sensitive to the pixel crosstalk caused by the fringing field of modern LCOS SLMS, leading to a significant undesired DC order. Two alternative strategies to avoid this degradation.

The work has been done in collaborators Jeffrey A. Davis and Don M. Cottrell from San Diego State University (USA). It is the first paper published by PhD student Shang Gao.

miércoles, 8 de noviembre de 2023 Sin comentarios

New paper in OLT about a liquid-crystal axicon for the generation of polarization varying Bessel beams

Our new paper entitled Liquid crystal anisotropic axicon for the generation of non-diffracting Bessel beams with longitudinally varying polarization is now publised in the journal Optics and Laser Technology.

In this work we demonstrate a tunable liquid–crystal element of linear phase profile along the radial coordinate. In combination with a regular refractive axicon, it behaves as an anisotropic axicon, generating the collinear superposition of two orthogonally polarized Bessel beams with different propagation constant. This superposition results in a Bessel beam where the state of polarization (SOP) varies periodically along propagation.

The work has been done with our collaborators at the Military University of Technology, Warsaw (Poland), Noureddine Bennis, Anna Spadlo and Tomasz Jankowski, together with José Francisco Algorri, from University of Cantabria, in Santander (Spain).

lunes, 30 de octubre de 2023 Sin comentarios

TecnOPTO at COS-SPIE Photonics Asia 2023

We have attended SPIE-COS Photonics Asia 2023 conference, held in Beijing in October 14-16th, 2023, organized by the Chinese Optical Society and SPIE. We have participated at the conference on Holography, Diffractive Optics, and Applications XIII.

Ignacio Moreno delivered the invited talk entitled Diffraction gratings with full amplitude, phase, and polarization control: physical realization on liquid-crystal spatial light modulators. María del Mar Sánchez-López delivered the invited talk entitled Triplicator phase grating implementation in pixelated displays. PhD student Shang Gao also attended the conference.

A great opportunity to meet in person the Chinese optical community.

The SPIE proceedings of these two works are now available at:

Proceedings Volume 12768, Holography, Diffractive Optics, and Applications XIII; 127681B (2023) – Link

Proceedings Volume 12768, Holography, Diffractive Optics, and Applications XIII; 127681G (2023) – Link

Categories: Conferences, International, Research Tags:
domingo, 22 de octubre de 2023 Sin comentarios

TecnOPTO at EOSAM2023 in Dijon

We have participated in the Annual Meeting of the European Optical Society, EOSAM2023, held in Dijon (France) in September 11-15th, 2023.

David Marco delivered the talk entitled «Mapping partially polarized light to incoherent superpositions of vector beams and vortex beams with orbital angular momentum», where he presented our recent article published in Journal of Optics.

Esther Nabadda gave the talk «Complete Mueller matrix imaging polarimeter for evaluating optical components for structured light», where she presented our new imaging polarimeter system.

Finally, Ignacio Moreno participated in the event as the new EOS Secretary of the Board of Directors, and as co-chair of the Focus Session on Structured Light.

Great time in a great conference!

sábado, 16 de septiembre de 2023 Sin comentarios

TecnOpto collaborates in a paper in OLEN of UAB MIP-Optilab about the indices of polarization purity

Esther Nabadda and Ignacio Moreno collaborated in the work entitled Connecting the microscopic depolarizing origin of samples with macroscopic measures of the Indices of Polarimetric Purity, published on the journal Optics & Lasers in Engineering. The work was leaded by our colleagues Juan Campos and Angel Lizana at UAB MIP-Optilab, in the frame of our coordinated joint research project.

In this work the indices of polarimetric purity (IPP) are analyzed as metrics to study the depolarization characteristic of media. It shows two different depolarizing origins: isotropic and anisotropic depolarization. The former, isotropic depolarization is related to pure scattering processes. Anisotropic depolarization is originated by microscopic constituent elements showing polarimetric anisotropy (dichroic and/or birefringent elements with different characteristics) and anisotropic scattering produced by these elements.

TecnOpto contributed to the experimental validation with radial polarizer and radial retarder measured with a Mueller matrix imaging polarimeter.

domingo, 10 de septiembre de 2023 Sin comentarios

TecnOPTO at the World of Photonics, Munich 2023

We have participated in the World of Photonics 2023 held in Munich (Germany) in June June 27–30, 2023.

David Marco attended CLEO-Europe conference, where he delivered the talk entitled «Mapping relations between the polarization, the higher-order and the orbital angular momentum Poincaré spheres for inner points», where he presented our recent article published in Journal of Optics.

Pascuala García-Martínez attended the SPIE Digital Optical Technologies 2023 conference, where she gave the talk «Polarization Fourier filtering with a 4f system using geometric phase lenses».

viernes, 30 de junio de 2023 Sin comentarios

TecnOpto at Reunión Nacional de Optoelectrónica – OPTOEL 2023

TecnOpto participated at the conference Reunión Naci0nal de Optoelectrónica – OPTOEL 2023, organized by SEDOPTICA in Sevilla in 14-16 June 2023.

We contributed wit two posters presented by our PhD Students Esther Nabadda, entitled «Mueller matrix polarimeter and birefringence imaging», and Shang Gao, entitled «Implementation of triplicator diffraction gratings in a pixelated display». Books of Abstracts.

We had the pleasure to meet there Massimo Santarsiero, one of the inventors of the triplicator grating.

Categories: Conferences, Research Tags:
miércoles, 21 de junio de 2023 Sin comentarios

New paper in Optics Express about using geometric lenses to perform polarization sensitive Fourier filtering

A new paper is published in Optics Express entitled Dual Fourier transform processor using geometric-phase lenses by Pascuala García-Martínez and Ignacio Moreno.

This work presents a novel optical system for polarization image processing using geometric-phase (Pancharatnam-Berry) lenses. These lenses present the same focal length but opposite sign for left and right circular polarizations. Therefore, they split an input collimated beam in a converging beam and a diverging beam with opposite circular polarizations. Here we profit from these properties to build an optical Fourier filter system with polarization sensitivity. A telescopic system is used to have access to two real Fourier transform planes, one for each circular polarization. A second symmetric optical system is used to recombine the two beams onto a single final image. As a result, polarization sensitive optical Fourier filtering can be applied, as demonstrated with simple bandpass filters.

Categories: Projects, Publications, Research Tags:
viernes, 5 de mayo de 2023 Sin comentarios

Elisabet Perez talks about light spectrum and adaptation at IB-UMH

On February 27th, 2023 we had the visit of Prof. Elisabet Perez, from the Facultat d’Òptica i Optometria de Terrassa (FOOT), at Universitat Politècnica de Catalunya (UPC).

She delivered the seminar «La importancia del espectro de la luz. Ejemplos de adaptación de la luz ambiental» (in Spanish) within the frame of the Institute of Bioengineering VII workshop «La Ciencia tiene nombre de mujer», in celebration of the 11th February, International Day of the Women and Girls in Science.

If you missed this excellent presentation by Prof. Perez, you can now view it in the following link

 

Categories: Education, Outreach, Women in Optics Tags:
martes, 18 de abril de 2023 Sin comentarios

New paper in Optical Engineering about the generation of vector beams with a new optical processor

Our last paper published in Optical Engineering is entitled Vector beams generated with a Fourier transform processor with geometric phase grating.

In this work we present a new method to generate vector beams with a 4f polarization Fourier filtering system that combines a spatial light modulator (SLM) at the input plane and a geometric phase polarization diffraction grating (PDG) at the output plane. This new systems presents advantages in terms of light efficiency and flexibility compared to other previous approaches.

The work has been done in collaboration with Prof. Jeffrey A. Davis and Prof. Don M. Cottrell from the Department of Physics at San Diego State University.

viernes, 10 de febrero de 2023 Sin comentarios