Room Temperature Exciton-Polariton Condensation in Silicon Metasurfaces Emerging from Bound States in the Continuum

We show the first experimental demonstration of room-temperature exciton-polariton (EP) condensation from a bound state in the continuum (BIC). This demonstration is achieved by strongly coupling stable excitons in an organic perylene dye with the extremely long-lived BIC in a dielectric metasurface of silicon nanoparticles. The long lifetime of the BIC, mainly due to the suppression of radiation leakage, allows for EP thermalization to the ground state before decaying. This property results in a condensation threshold of less than 5 \mu J cm^{-2}, one order of magnitude lower that the lasing threshold reported in similar systems in the weak coupling limit

Tailoring Polarization Conversion in Achiral All-Dielectric Metasurfaces by Using Quasi-Bound States in the Continuum

Quasi-bound states in the continuum (quasi-BICs) supported in all-dielectric metasurfaces (MTS) are known for their confinement in real space and the notably high values of the quality factor Q. Recently, the properties of quasi-BICs have been employed to achieve polarization conversion with all-dielectric MTS. However, one of the main disadvantages of the current approaches is the dependence on the chirality of either the meta-atoms or their disposition. We present the possibility of achieving polarization conversion by using all-dielectric MTS with square and rectangular lattices of nano-disks. The precise tuning of the lattice and disks parameters allows to transform linearly polarized light into circularly polarized light with near unity polarization rates while maintaining the high Q values of quasi-BICs. Moreover, by using double accidental BICs it is possible to obtain right and left circularly polarized light on demand just by varying the angle of incidence

Optical and Electrical Properties of Low-Dimensional Crystalline Materials: A Review

Low-dimensional materials have been revolutionary in both the technological and research fields over the last decades. Since the discovery of graphene in 2004, and thanks to the technological improvements in nanotechnology achieved during this last century, the number of low-dimensional materials under research and their potential applications have not stopped increasing. In this review, we present a comprehensive tour of the principal 2D and 1D materials that compose the current state of the art and also the technological applications derived from them. In both cases, the focus will be on their optical and electrical properties, as well as the potential applications on novel photonic, electronic, or optoelectronic devices. For 2D materials, we will focus on a brief review of graphene-like materials, giving more emphasis to graphene derivatives, hexagonal boron nitride, and transition metal dichalcogenides. Regarding 1D materials, we will aim at metallic and semiconductor nanowires. Nevertheless, interesting 2D and 1D materials are mentioned in each section. The topic will be introduced using the related origin of their unique capabilities as a common thread. At the same time, we will try to remark on the differences and similarities between both groups and their physical relationship

Optical and Electrical Properties of Low-Dimensional Crystalline Materials

Low-dimensional materials have experienced a real revolution in both the technological and research fields in recent decades [...

La Gamificación en el proceso de la enseñanza de los idiomas.: Gamification in the Language Teaching Process

El objetivo de esta investigación fue implementar la gamificación como herramienta de apoyo en el Colegio de Estudios Generales y de Servicios (CEGES) año escolar 2022-2023. Esta investigación asume el enfoque cualitativo, la investigación-acción, método etnográfico. Las técnicas para recopilar información fueron la encuesta,la entrevista y la observación. Se concluyó que la gamificación es una herramienta que aporta interés, motivación y atracción al proceso de enseñanza de los idiomas no solamente a los alumnos sino también a los docentes, acorde a los análisis expresados teóricamente y que fundamenta la importancia de su aplicabilidad durante el proceso de enseñanza de lenguas extranjeras o idioma. Los docentes del área de idiomas fueron capacitados con el uso de las 4 herramientas de gamificación adquiriendo estos los conocimientos de las herramientas Kahoot, Socrative, Quizziz y Educaplay, logrando que su proceso de enseñanza sea más dinámico. Esto se pudo evidenciar en las actividades realizadas por los docentes a través de los encuentros de capacitación y a través de las observaciones directas en las clases impartidas por los docentes de idiomas del Centro Educativo CEGES

Defects-Recognition, Imaging and Physics in Semiconductors (DRIP) XVIII

Conclusions Local hot spots produce a thermal lensing effect that focuses the travelling wave on a point situated ~ 3 - 5 μm behind the heated region. If the heated region is fully degraded, the laser cavity modes present maxima which are located ~ 3 - 5 μm in front of the degraded region. The simulations suggest that a new COD process would be triggered at about 3 μm from the previously heated/degraded region, in good agreement with the experimental CL resultsProyecto de Investigación ENE2017-89561-C4-3-R (MCIN)Proyecto de Investigación VA283P18 (Junta de Castilla y León

Tailoring Polarization Conversion in Achiral All-Dielectric Metasurfaces by Using Quasi-Bound States in the Continuum

Quasi-bound states in the continuum (quasi-BICs) supported in all-dielectric metasurfaces (MTS) are known for their confinement in real space and the notably high values of the quality factor Q. Recently, the properties of quasi-BICs have been employed to achieve polarization conversion with all-dielectric MTS. However, one of the main disadvantages of the current approaches is the dependence on the chirality of either the meta-atoms or their disposition. We present the possibility of achieving polarization conversion by using all-dielectric MTS with square and rectangular lattices of nano-disks. The precise tuning of the lattice and disks parameters allows to transform linearly polarized light into circularly polarized light with near unity polarization rates while maintaining the high Q values of quasi-BICs. Moreover, by using double accidental BICs it is possible to obtain right and left circularly polarized light on demand just by varying the angle of incidence

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field