Grupo de Tecnologías Ópticas y Optoelectrónicas

Our last article is published in the journal Optics & Lasers in Engineering, entitled Study of symmetry and retracing properties of geometric phase gratings and lenses. Here we analyze the symmetry properties of polarization sensitive geometric phase gratings and geometric phase lenses, and compare them with the regular scalar elements.

Experimental results are included that evidence these properties with simple optical arrangements. These include experiments where the gratings are used in a transmission configuration, and others where a mirror is added to analyze a counter-propagated beam.

Ignacio Moreno coauthored a recent review paper in Applied Sciences that describes the advances accomplished in the application of polarization metrics based on the Polarizance-Reflection-Transformatin (PRT) and the Indices of Polarization Purity (IPP) to to distinguish between non-depolarization systems.

The review has been published in the journal Applied Sciences with the title: IPP and PRT Depolarizing Spaces for the Study of Depolarizing Samples: A Review.

Ignacio Moreno participated at the 4th International Workshop on Biophotonics and Angular Optical Momentum – BIOAM2025, held at École Polytechnique, Palaiseau (France), in 1-3 September 2025.

He was member of the Scientific Advisory Board and he delivered the invited talk entitled ‘Fourier transform Jones matrix approach for polarized structured light’.

Ignacio Moreno was this year one of the General Chairs of the Annual Meeting of the European Optical Society, EOSAM2025, held in Delft (The Netherlands) in 24-28 August 2025.

Ignacio delivered again a tutorial on «Spatial Light Modulators» in collaboration with the company Holoeye Photonics.

Our last paper entitled Triplicator phase-only hologram and its use as a snapshot optical convolver and correlator is now published in he Journal of the European Optical Society – Rapid Publications.

In this work we extend the optimum phase triplicator diffraction grating profile to a phase-only hologram. This modified hologram generates three equally-energetic orders with the highest diffraction efficiency, yielding a direct version and an inverted complex conjugate version of the target pattern in the ±1st orders, respectively, and a delta function in the DC zero order. When combined with another phase-only function, the resulting hologram yields convolution and correlation terms in the ±1st orders, respec- tively, while the target function encoded in the added phase appears in the zero order. Experimental results obtained with a high-resolution liquid-crystal phase-only spatial light modulator (SLM) demonstrate the proposed design.

This work is part of the PhD Thesis of Shang Gao.

Our last work, entitled Optical beams with spatially variant coherence properties from an unpolarized laser has been published in the journal Optics & Laser Technology.

In this work we demonstrate how to generate quasi-monochromatic laser beams with engineered, non-uniform transverse spatial coherence properties using an unpolarized helium–neon laser. This is achieved with a static phase modulating device that spatially modulates the laser’s two orthogonal polarization components, followed by a linear polarizer.

We demonstrate the method wih patterned geometric phase elements or and with programmable liquid-crystal spatial light modulators. The technique exploits the nanosecond-timescale variation of the laser’s emitted polarization ellipse, creating configurable non-uniform coherence patterns that maintain their spatial coherence characteristics down to nanosecond temporal windows.

This work has been leaded by David Marco during his postdoctoral stay at TecnOpto Lab during 2024.

Pascuala García and Ignacio Moreno were invited by the members of the GROC research group at Universitat Jaume I (UJI) to participate at the third topical school of the Computational Imaging as training network for smart biomedical devices – CONcISE held in Castellón during the days June 2nd to 5th 2025.

Ignacio Moreno delivered the talk entitled «Digital control of light beams with spatial light modulators 1: liquid crystal displays» on June 3rd. The next day, Pascuala García delivered the talk «Gender perspective and equality in research».

We are grateful to our colleagues at UJI for the invitation and hospitality.

Last week Ignacio Moreno visited the University of Salamanca (USAL) where he delivered the tutorial entitled «Liquid-Crystal Spatial Light Modulators For Structured Light».

During his visit he could interact with the members of LUMES, the Unit of Excellence in Structured Light and Matter of USAL.

This visit is within the frame of FASLIGHT, the Spanish Network on Structured Light, which coordinated by the LUMES group.

A great pleasure to visit USAL and know directly about the great research developed by LUMES!

Our last publication in Optics Express is entitled Liquid-crystal adaptive equivalent q-plate device with tunable topological charge.

In this work we present a novel compact and transmissive device useful to generate cylindrical vector beams (CVBs) of tunable topological charge. The device combines two adaptive spiral phase plates (ASPP) in orthogonal directions and a quarter-wave plate (QWP). Each ASPP relies on a specially designed circular transmission electrode with radial lines to generate a spiral phase upon addressing two voltages. The combination of two orthogonal ASPP allows imparting two independent spiral phases onto two orthogonal linear polarization states that are converted into circular states by the final QWP, thus efficiently realizing arbitrary CVBs.

By adjusting the four addressed voltages, the topological charges can be tuned to provide pure or hybrid CVBs with arbitrary topological charges. The device performance is analyzed in terms of the mapping relations between the Poincaré sphere and the higher-order Poincaré sphere. We find that it performs as a q-plate, but with the remarkable advantage of providing dynamic control of the topological charge in vortices and CVBs. Hence, we name it adaptive q-plate (AQ-plate).

This work was developed with Prof. Noureddine Bennis and his team at WAT (Wojskowa Akademia Techniczna), the Military Universiy of Technology, in Warsaw, Poland.

This week Angel Sanz, from the Department of Optics at Universidad Complutense de Madrid (UCM), visited TecOpto labs. We also received the visit of Adam Vallès and Javier Fermández, from ICFO and Universitat Autònoma de Barcelona, so we could have a miniworkshop on Structured Light.

This is part of the activities of FASLIGHT – the Spanish Network of Fundamentals and Applications of Structured Light.