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 GarcÃa 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 GarcÃa 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.
Our recent paper in Optics Letters is entitled Shaped vector beams generated with a phase-only modulation—retarder optical configuration.
In this work we present a new configuration to generate vector beams, with shaped intensity and polarization distributions. The system is based on using on two liquid-crystal spatial light modulators (SLM). The first device is used in a scalar mode to shape an input linearly polarized beam with a phase-only computer-generated hologram. Then, the Fourier transform is optically formed onto the second SLM, which operates as a pixelated retarder to spatially modify the state of polarization. The proposed optical architecture allows shaping the amplitude profile,
while easily generating the cylindrically polarized vector beam pattern.
The work has been done in collaboration with Prof. Jeffrey A. Davis and Prof. Don M. Cottrell, from San Diego State University.
Access through Research Gate.
Ignacio Moreno delivered a talk about structured light and programmable optics at the Faculty of Physics of the University of Valencia.
The presentation was part of the Faculty’s lecture series. Ignacio introduced the fundamentals of structured light, its control and generation with liquid crystal devices, and the generation of diffraction patterns with structured polarization elements, such as spatially varying polarizers or retarders.
Santiago RÃos joined TecnOpto Lab. He is coming from Universidad Nacional de Colombia. He is recipient of a «Santiago Grisolia» grant, to do his PhD Thesis during the next four years.
The picture shows the current TecnOpto team: from left to right, Ignacio Moreno, Shang Gao, Santiago RÃos, MarÃa del Mar Sánchez-López and Pascuala GarcÃa.
miércoles, 29 de enero de 2025
i.moreno
Ignacio Moreno participated at Optics & Photonics Japan 2024, the Annual Meeting of the Optical Society of Japan (OSJ), held in Chofu City, Tokyo, between November 29th and December 1st.2024.
During the event, he delivered a talk on «Liquid-crystal optical modulators for diffractive and polarization control» in the Plennary Session, where he represented the European Optical Society (EOS).
In the picture Prof. Yoshimasa Kawata, President of OSJ, alongside Ignacio Moreno.