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.
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 Ríos 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 Ríos, María del Mar Sánchez-López and Pascuala García.
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.
On Friday 11th October 2024 we had the visit of Dr. Alberto Álvarez Herrero, researcher at Instituto Nacional de Técnica Aeroespacial (INTA) and co-founder of the deep-tech start-up Eye4Sky, which develops liquid-crystal technologies for space applications.
Alberto visited the TecnOpto labs and delivered a talk entitled «Eye4Sky: From research to the creation of a company of optical space technology», within the frame of the UMH Doctoral Program on Industrial and Telecommunications Technologies (TECNIT).
The talk (in Spanish) can be viewed at the following link.
Here we analyze diffraction gratings displayed on a pixelated SLM at its spatial resolution limit (Nyquist limit) i.e., with largest diffraction angle, where the binary phase profile is the only alternative. We use the Fourier transform theory to analyze the binary phase grating in a pixelated device in terms of the pixel size, fill factor and phase difference between the two levels in the grating.
Experimental verification is provided by encoding binary phase triplicator gratings with different periods on a high-resolution liquid-crystal on silicon SLM. The effect of the device pixelation and pixel crosstalk on the diffraction efficiency and on the conditions to obtain a Nyquist triplicator phase grating are studied.
This paper is part of the PhD Thesis developed by Shang Gao.
Ignacio Moreno and David Marco attended the Annual Meeting of the Euorpan Optical Socierty, EOSAM2024, held in Napoli (Italy) in 9-13 September 2024.
Ignacio Moreno delivered the tutorial on «Spatial Light Modulators» in collaboration with the company Holoeye Photonics. He was also co-chair of the Focused Session 1 on «Holography and Structured Light».
David Marco presented the talk entitled «Polarization diffractive elements analyzed with the Fourier transform Jones matrix and with the beam coherence polarization matrix«, where he summarized our recent work published in Results in Physics (link).
Ignacio Moreno visited WAT (Wojskowa Akademia Techniczna), the Military Universiy of Technology, in Warsaw, Poland. He stayed four weeks at the Laboratory of Crystal Physics and Technology (LCPT), included in the structure of the Institute of Applied Physics, Faculty of Advanced Technologies and Chemistry.
This stay allows continuing the fruitful collaboration with researchers from this center, in particular with Prof. Noureddine Bennis and Prof. Anna Spadło. In particular, the work was centered in the joint research on developing and characterizing liquid-crystal devices for the generation of structured light.
The stay of four weeks was financed by Generalitat Valenciana through the program CIBEST/2023.
Here we integrate the Fourier transform Jones (FTJ) matrix approach with the beam coherence- polarization (BCP) matrix, suitable for describing partially coherent and partially polarized light.
We apply the method to a meaningful example: a rectangular aperture with orthogonal polarizers on each half, illuminated with uniform randomly polarized light. We provide experimental validation using a randomly polarized He-Ne laser and a specially fabricated double polarizer mask. Furthermore, by placing a polarizer behind the polarization diffractive optical element, we generate a scalar beam with spatial incoherence across two distinct zones, suggesting the potential use of randomly polarized lasers with binary patterned polarizers to encode arbitrary binary coherence functions.
The work has been done in collaboration with our colleagues Juan Campos and Angel Lizana, from Universitat Autònoma de Barcelona.
We offer a new Pre-Doctoral Contract for the realization of a PhD Thesis within the project CIGRIS/2023/043 of Generalitat Valenciana.
Required conditions: The candidate must hold a Degree in Physics, Engineering, Optics or similar from a non-EU institution. The degree title must have been obtained after 1st January 2019. The degree must qualify to enter a PhD program. Candidates must not hold a previous PhD.
If interested contact before August 20th Prof. María del Mar Sánchez López () and provide CV and Academic Certificate, motivation letter and a contact of a person who can provide a recommendation.
We are looking for motivated candidates to perform a PhD Thesis in the field of structured light, with willingness to collaborate at international level. Tasks to perform: Developing optical systems and methods to control the polarization of light for applications in microfabrication, polarization imaging and optical communications. The activities will comprise experimental tasks at TecnOpto Lab involving spatial light modulators and other optical equipment, as well as theoretical analysis and computer simulations. Recommended experience: Background in optics or optoelectronics; programming skills(Python, Matlab, Labview…); fluent English written and spoken (Spanish will be valued); teamwork and communications kills.
Contract Duration:4 years (renewable every year). Annual gross salary of 23,796.96 €, plus up to 1,600 euros to cover travel and location expenses. Social security and institutional benefits included. Starting Date: 1st November 2024 or 1stJanuary 2025.
Our recent paper in Optics Letters is entitled Shaped vector beams generated with a phase-only modulation—retarder optical configuration.
