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Photopolymers have been used mainly for holographic recording applications. Nowadays, the improvements made in diffusion models, simulating phase image stored in these materials, enable a wide range of complex diffractive optical elements (DOEs) to be fabricated. Concurrently, the miniaturization of spatial light modulators makes it possible to generate both symmetric and non-symmetric DOEs. We show the procedure to record different complex diffractive elements, and we study the viability to fabricate them based on photopolymers. In particular we evaluate the recording of achromatic lenses, axicons and fork gratings interesting to obtain optical vortices. To achieve this goal, we use a three-dimensional diffusion model, previously experimentally validated with the recording of diffractive lenses.

Descripción breve y sencilla de iniciativas docentes en nuestros colegios e institutos que han de ser resaltadas, de investigaciones relevantes de autores españoles o de extranjeros en instituciones españolas, y de otros hechos interesantes sobre ciencia y enseñanza, políticas educativa y científica y sus actores. Sección preparada por Augusto Beléndez, en colaboración con actores implicados, que anima a proponer contribuciones relevantes para ser consideradas aquí. 1. Una nueva forma de identificar las imprevisibles cuencas de Wada en sistemas caóticos. 2. Nueva familia de clusters de carbono obstaculiza el crecimiento de grafeno en metales. 3. Nanodispositivos con aplicaciones en el campo de la óptica. 4. Control reversible de dominios ferroeléctricos mediante luz polarizada. 5. El papel constructivo del ruido. 6. MUDIC: aprender física y disfrutar.

El modelo educativo con enfoque en la formación de competencias, promovido a principios del siglo XXI y que ha tomado un papel muy importante en el proceso enseñanza-aprendizaje en las instituciones educativas de todos los niveles educativos, establece que para el desarrollo armónico del ser humano la educación debe ser integral. La educación basada en competencias está orientada hacia la generación de capacidades en el educando y por ello, la evaluación debe centrarse en éstas, particularmente las que tienen que ver con habilidades para identificar, proyectar, resolver problemas y tomar decisiones. Las rúbricas de evaluación por competencias son una herramienta que permite obtener evidencia de la adquisición de éstas y aplicación del conocimiento fuera del aula. Esto supone un cambio en el escenario escolar, tanto para los profesores, así como también para los estudiantes, quienes deben asumir nuevas funciones, roles y tareas para lograr un aprendizaje basado en competencias genéricas y específicas. En este trabajo se presenta una propuesta de rúbricas para la evaluación por Competencias de Física en el ámbito universitario, específicamente, para evaluar el desarrollo de prácticas de laboratorio. Con este trabajo, se pretende introducir nuevos métodos de evaluación e identificar oportunidades para desarrollar capacidades y evaluar aprendizajes a través de indicadores de progreso. En esta primera fase del proyecto, se ha diseñado una práctica de laboratorio y en conjunto se ha elaborado la rúbrica de evaluación, aplicada a alumnos de Fundamentos Físicos de la Informática en el Grado de Ingeniería Informática de la Escuela Politécnica Superior de la Universidad de Castilla-La Mancha (UCLM), situada en el campus universitario de Albacete., The educational model with focus on competency formation, promoted at the beginning of the XXI century and which has taken a very important role in the teaching-learning process in educational institutions of all educational levels, it establishes that for the development of the human being education must be integral. Competency-based education is oriented towards the generation of skills in the student, therefore, the evaluation should focus on these, particularly those that have to do with abilities to identify, project, solve problems and make decisions. The rubrics of competency evaluation are a tool that allows to obtain evidence of the acquisition of these and application of knowledge outside the classroom. This implies a change in the university’s scenario, both for the teachers, as well as for the students, who must assume new functions, roles and tasks to achieve a learning based on generic and specific competences. In this work a proposal of rubrics for the evaluation by Physics Competences in the university area is presented, specifically, to evaluate the development of laboratory practices. With this work, it is intended to introduce new assessment methods and identify opportunities to develop skills and evaluate learning through indicators of progress. In this first phase of the project, a laboratory practice has been designed and together the evaluation rubric has been developed, applied to students of Physical Foundations of Informatics in the Degree of Computer Engineering of the Higher Polytechnic School of the University of Castilla -La Mancha (UCLM), located on the university campus of Albacete.

Competence-based education is oriented towards an evaluation model linked to student training, in order to foster the development of abilities to identify, project, solve problems and make decisions. In this context, the rubrics allow obtaining evidence of the acquisition of competences and application of knowledge outside the classroom. In this work, we present a proposal for the development of a Physics laboratory practice with the use of a rubric for the evaluation by competences in the university field. We want to introduce new assessment methods and identify opportunities to develop skills and evaluate learning through indicators of progress.

The training of the students of electrical mechanical engineering is based on the acquisition of disciplinary knowledge in the areas of thermodynamics, mechanical, electrical and electronic design, quality control, safety and hygiene and materials. Bringing the application of this knowledge to the solution of real problems requires higher-order cognitive skills such as the development of complex thinking among others. Case-based Learning (CBL) is a methodology that favors active learning and the construction of arguments, allowing students to see theory in the practice in a real-life context. In materials engineering, characterization techniques allow to evaluate the properties of the materials and thereby determine if the material is useful for a given application. Traditionally students learn this content from following procedures, but deciding which technique to use causes those difficulties, especially when it is necessary to define the variables to be measured. Within the course of materials engineering, a case-based educational strategy was applied to a group of 19 students of electrical mechanical Engineering at a public University of San Luis Potosi, Mexico with the purpose of evaluating the knowledge acquired in the subject. The solution of the case "the Ouija of the Devil: the Molecular detector GT200", allowed to identify the level of knowledge on characterization techniques, the variables involved, the limitations and necessary parameters to carry out the measurements, on the other Side, the importance of scientific knowledge was identified to solve problems and its impact on decision-making in public policies and resource management. As this is a case associated with the acquisition of equipment by the Mexican government, whose functions were totally false, it allowed exploring the attitudes of t students towards the corruption and the necessary values to practice the profession. The proposed methodology was that of CBL, the learning evidence was analyz

The evolution of the species has led us to adapt and live in an environment of electromagnetic waves of low frequency and low intensity of natural origin: proceeding from the Sun and Storms. In addition, we have gotten used to the Earth’s weak magnetic field, which is practically stationary. However, human activity has altered this natural balance with more intense electromagnetic fields and with a very different spectral distribution of frequencies. In the past two decades, personal exposure to Radiofrequency Electromagnetic Fields (RF-EMF) has experimented an important increase due to the development of the information society, and at some point, we have wondered whether these have any negative effects on health, some out of concern and some out of curiosity. Parallel to the increase of the exposure to RF-EMF, the concern regarding the potential health effects has increased. Among the most feared effects, stands out the possible relationship of the RF-EMF with some diseases of the brain of unspecified causes, which has motivated numerous epidemiological studies. However, many of these studies have focused almost exclusively in the location of the antennas of mobile phones, and not in involving the participants to disseminate the results with society. In this context, the use of personal Expometers allows to study the RF-EMF exposition in great detail (spatial, temporary, number of bands, precision, etc.) and/or characterize the exposure level of the population in different micro environments, where it is possible to study if there is spatial correlation with the incidence of any disease. Some studies propose alternatives to assess exposure in different micro environments, using different models elaborated from point measurements or elaborating exposure maps. In view of the growing public concern about the possible health effects of RF-EMF, we believe that a modern society must be sufficiently informed of all technological developments and possible health implicati

The conceptual maps allow representing graphically the existing relationships between ideas, associations, and hierarchies. They have been used in recent years in learning all areas of knowledge and educational levels in academic and non-academic environments. Due to the fact that they facilitate reading, they favor memorization and metacognition; they also describe the aspects that compose a whole. In Physics’ learning, they have been used to identify previous knowledge, to evaluate the acquired learning, to summarize texts, but its use has been little exploited in the accompaniment to the solution of Physics problem. This work presents an educational strategy that allows guiding the student during the realization of problems through the use of conceptual maps and infographics, which can be applied in university students and other educational levels, using as a reference the Taxonomy of Introductory Physics Problems (TIPP).

The competency-based educational model, that initiated at the beginning of the XXI century plays a very important role during the teaching-learning process in higher education institutions, it establishes that for the development of the human being education must be integral. Competency-based education is oriented towards an evaluation model linked to student training, in order to foster the development of skills and abilities to identify, project, solve problems and make decisions. In addition, it promotes the pursuit of meaningful learning and fosters collaborative work. In this context, the rubrics of competency evaluation appeared as a tool that allows obtaining evidence of the acquisition of competences and application of knowledge outside the classroom. This implies a change in the university’s scenario, both for teachers and for students, as there are new roles and tasks to achieve learning based on generic and specific competencies. In this work we present a proposal of rubrics for the evaluation by Physics Competences in the university field, specifically, to evaluate the development of laboratory practices. Also, we want to introduce new assessment methods and identify opportunities to develop skills and evaluate learning through indicators of progress. In this first phase we have designed a laboratory practice, and we have developed the evaluation rubric applied to students of Physical Foundations of Informatics in the Degree of Computer Engineering of the Higher Polytechnic School of the University of Castilla -La Mancha (UCLM), located on the university campus of Albacete.

Innovative technologies demand versatile and environmentally compatible optical elements. In this paper we evaluated the quality of volume phase transmission lenses stored in a biocompatible photopolymer. Holographic lenses (HL) have been obtained with the same focal and diameter, for a symmetric and asymmetric experimental setups, and positive and negative focal. The quality of these lenses have been evaluated: theoretically and experimentally, from the calculation of the modulation transfer function (MTF) by capturing the point spread function (PSF) with a CCD sensor. The HLs that have shown better quality are the negative asymmetrically recorded compared with the theoretical ones.

James Clerk Maxwell (1831-1879) es uno de los científicos más importantes de la historia de la ciencia y, sin embargo, es bastante desconocido para el gran público. Tomando como hilo conductor su artículo “A Dynamical Theory of the Electromagnetic Field” publicado en 1865, se hace un recorrido a través de la vida y la ciencia de Maxwell, y se concluye con la “síntesis maxwelliana” que no sólo permitió unificar luz, electricidad y magnetismo, sino desarrollar la teoría de las ondas electromagnéticas, incluida la luz.

En este trabajo evaluamos la calidad de lentes holográficas de volumen almacenadas en un fotopolímero respetuoso con el medio ambiente llamado Biophotopol. Las lentes holográficas (HL) se han obtenido en configuraciones experimentales simétricas y asimétricas con distancia focal negativa. La calidad de estas lentes se ha evaluado calculando la función de transferencia de modulación (MTF) para dos longitudes de onda (473 y 633 nm). Las HL que han demostrado una mejor calidad de imagen son las registradas asimétricamente y evaluadas a 473 nm.

We study the behaviour and compare two nanostructurated materials based on multifunc- tional monomers: a nanoparticle-thiol-ene-polymer composite (NPC) and a holographic polymer dispersed liquid crystals (HPDLC) with dipentaerythritol penta/hexa-acrylate (DPHPA) as main monomer. We evaluate their suitability to record complex large grating spacing diffractive optical elements (DOEs), such as blazed gratings. Thus, we can explode their multifunctional capabilities to develop electrically tunable DOEs, thanks to the addition of LC molecules.

Recientemente propusimos un modelo simplificado que permite predecir con una incertidumbre inferior al 5% el retardo que producen las pantallas de cristal líquido sobre silicio (PALCoS) a lo largo del espectro visible y para cualquier ángulo de incidencia entre 0º y 45º. Aquí mostramos que el modelo también nos permite calcular propiedades fundamentales de la capa de cristal líquido, tales como el ángulo de inclinación en función del voltaje aplicado y la birrefringencia.

In this paper, we present a method to characterize a complete optical Holographic Data Storage System (HDSS), where we identify the elements that limit the capacity to register and restore the information introduced by means of a Liquid Cristal on Silicon (LCoS) microdisplay as the data pager. In the literature, it has been shown that LCoS exhibits an anamorphic and frequency dependent effect when periodic optical elements are addressed to LCoS microdisplays in diffractive optics applications. We tested whether this effect is still relevant in the application to HDSS, where non-periodic binary elements are applied, as it is the case in binary data pages codified by Binary Intensity Modulation (BIM). To test the limits in storage data density and in spatial bandwidth of the HDSS, we used anamorphic patterns with different resolutions. We analyzed the performance of the microdisplay in situ using figures of merit adapted to HDSS. A local characterization across the aperture of the system was also demonstrated with our proposed methodology, which results in an estimation of the illumination uniformity and the contrast generated by the LCoS. We show the extent of the increase in the Bit Error Rate (BER) when introducing a photopolymer as the recording material, thus all the important elements in a HDSS are considered in the characterization methodology demonstrated in this paper.

We study the behavior of a nanoparticle-polymer composite (NPC) material, based on a thiol-ene monomer system, working with long grating spacing. Thus, we evaluate the suitability of the NPC for storing complex diffractive optical elements with sharp profiles, such as blazed gratings. Using holographic methods, we measure the “apparent” diffusion of the material and the influence of the spatial period on this diffusion. The applicability of this material in complex diffractive optical elements (DOEs) recording is analyzed using an interferometric method. Supported by the results of this analysis, we record blazed gratings with different grating spacing and measure the maximum diffraction efficiency (DE) achieved. The results show that NPC has a good behavior in this range of spatial frequencies.

La siguiente presentación corresponde a la conferencia "Utilidades del repositorio científico para un investigador" impartida el 17 de abril de 2018 en la Universidad de Huelva dentro del Ciclo de Conferencias "Los repositorios científicos y el acceso abierto: instrumento clave para la actividad investigadora" organizado por el Vicerrectorado de Investigación y Transferencia y la Biblioteca Universitaria de la Universidad de Huelva.

In this work, an accurate numerical modeling of the diffraction properties of transmission holographic polymer dispersed liquid crystal (H-PDLC) gratings is presented. The method considers ellipsoid geometry-based liquid crystal (LC) droplets with random properties regarding size and location across the H-PLDC layer and also the non-homogeneous orientation of the LC director within the droplet. The direction of the LC director inside the droplets can be varied to reproduce the effects of the external voltage applied in H-PDLC-based gratings. From the LC director distribution in the droplet, the permittivity tensor is defined, which establishes the optical anisotropy of the media, and it is used for numerically solving the light propagation through the system. In this work, the split-field finite-difference time-domain method (SF-FDTD) is applied. This method is suited for accurately analyzing periodic media, and it considers spatial and time discretisation of Maxwell’s equations. The scheme proposed here is used to investigate the influence on the diffraction properties of H-PDLC as a function of the droplets size and the bulk fraction of LC dispersed material.

In recent works, we demonstrated the accuracy and physical relevance of a highly simplified reverse-engineering analytical model for a parallel-aligned liquid crystal on silicon devices (PA-LCoS). Both experimental measurements and computational simulations applying the rigorous split-field finite difference time domain (SF-FDTD) technique led to this conclusion in the low applied voltages range. In this paper, we develop a complete rigorous validation covering the full range of possible applied voltages, including highly non-linear liquid crystal (LC) tilt angle profiles. We demonstrate the applicability of the model for spectral and angular retardation calculations, of interest in spatial light modulation applications. We also show that our analytical model enables the calculation of the retardance for novel PA-LC devices as a function of the LC compound and cell gap, becoming an appealing alternative to the usual numerical approaches for PA-LC devices design.

Liquid crystal on silicon (LCoS) displays have become the most attractive microdisplays for all sort of spatial light modulation applications. Among the different LCoS technologies, parallel aligned LCoS (PA-LCoS) are especially interesting. They offer unique capabilities as spatial light modulators (SLM), since they enable phase-only modulation without coupled amplitude modulation, and with millions of addressable pixels. In this work we evaluate and demonstrate the various capabilities offered by a novel and simplified physical model for parallel aligned liquid crystal devices (PA-LC), thus also applicable to PA-LCoS microdisplays. The model provides the voltage dependent retardance values, necessary for spatial light modulation applications, for a very wide range of incidence angles and any wavelength in the visible. First, it needs to be calibrated through a reverse-engineering approach. In this calibration, the values obtained for two of the three parameters provide the correct values for important internal properties of these devices related with the birefringence, cell gap and director profile. Therefore, the proposed model can be used as a means to inspect internal physical properties of the cell. Last but not least the model is useful to simulate the retardance for novel PA-LC devices as a function of the LC compound and cell gap. Therefore, it is not only a reverse-engineering model but it also constitutes an analytical alternative to the usual numerical approaches for PA-LC devices design and construction.

The technologies based on holographic and photonic techniques related to the optical storage and optical processing of information are rapidly evolving. One of the key points of this evolution are the new recording materials able to perform under the most specific situations and applications. In this sense, the importance of the photopolymers is growing spectacularly. This is mainly due to their versatility in terms of composition and design together with other interesting properties such as self-processing capabilities. In this chapter, we introduce the diffractive optical elements (DOE) generation in these materials and some of the most important parameters involved in this process. The deep knowledge of the material is essential to model its behavior during and after the recording process and we present different techniques to characterize the recording materials. We also present a 3D theoretical diffusion model able to reproduce and predict the experimental behavior of the recording process of any kind of DOE onto the photopolymers. The theoretical results will be supported by experimental analysis using a hybrid optical-digital setup, which includes a liquid crystal on silicon display. Besides this analysis, we study a method to improve the conservation and characteristics of these materials, an index-matching system.

In this paper, we theoretically and experimentally evaluated the quality of volume phase transmission lenses stored in an environmentally friendly photopolymer. Holographic lenses (HLs) were obtained using symmetrical and asymmetrical experimental setups with the same positive and negative focal length and pupil diameter. The image quality was evaluated from the calculation of the modulation transfer function (MTF) by capturing the point spread function (PSF) with a charge-coupled device (CCD). A maximum frequency of 14 L/mm, reaching an MTF value of 0.1, was obtained for a negative asymmetrically recorded HL, evaluated at 473 nm wavelength. A theoretical study of aberrations was carried out to qualitatively evaluate the experimental results obtained.

En esta conferencia se muestran diversos aspectos sobre la vida y las contribuciones científicas de James Clerk Maxwell, uno de los científicos más importantes de la historia de la ciencia. Asimismo, se hace especial énfasis a los aspectos relacionados a su actividad docente en Aberdeen, Londres y finalmente en Cambridge. Se muestran también algunas de sus ideas relacionadas con la enseñanza de la física, incidiendo en la importancia que daba al laboratorio dentro de una formación completa en física.

Simplified analytical models with predictive capability enable simpler and faster optimization of the performance in applications of complex photonic devices. We recently demonstrated the most simplified analytical model still showing predictive capability for parallel aligned liquid crystal on silicon devices (PA-LCoS), which provides the voltage dependent retardance for a very wide range of incidence angles and any wavelength in the visible. In this work we further show that the proposed model is not only phenomenological but it is also physically meaningful, since two of its parameters provide the correct values for important internal properties of these devices related with the birefringence, cell gap and director profile. Therefore, the proposed model can be used as a means to inspect internal physical properties of the cell. Also as a novelty, we also show the applicability of the split-field finite difference time domain (SF-FDTD) technique for phase-shift and retardance evaluation of PA-LCoS devices under oblique incidence. As simplified model for PA-LCoS devices we also consider the exact description of homogeneous birefringent slabs. However, we show that despite its higher degree of simplification the proposed model is more robust, providing unambiguous and physically meaningful solutions when fitting its parameters.

Closed-form exact solutions for an oscillator with anti-symmetric quadratic nonlinearity are derived from the first integral of the nonlinear differential equation governing the behaviour of this oscillator. The mathematical model is an ordinary second order differential equation in which the sign of the quadratic nonlinear term changes. Two parameters characterize this oscillator: the coefficient of the linear term and the coefficient of the quadratic term. Not only the common case in which both coefficients are positive but also all possible combinations of positive and negative signs of these coefficients which provide periodic motions are considered, giving rise to four different cases. Three different periods and solutions are obtained, since the same result is valid in two of these cases. An interesting feature is that oscillatory motions whose equilibrium points are not at x = 0 are also considered. The periods are given in terms of an incomplete or complete elliptic integral of the first kind, and the exact solutions are expressed as functions including Jacobi elliptic cosine or sine functions.