Guided resonances in photonic quasicrystals

In this paper, we report on the first evidence of guided resonances (GRs) in aperiodically-ordered photonic crystals, tied to the concept of "quasicrystals" in solid-state physics. Via a full-wave numerical study of the transmittance response and the modal structure of a photonic quasicrystal (PQC) slab based on a representative aperiodic geometry (Ammann-Beenker octagonal tiling), we demonstrate the possibility of exciting GR modes, and highlight similarities and differences with the periodic case. In particular, we show that, as for the periodic case, GRs arise from the coupling of the incident plane-wave with degenerate modes of the PQC slab that exhibit a matching symmetry in the spatial distribution, and can still be parameterized via a Fano-like model. Besides the phenomenological implications, our results may provide new degrees of freedom in the engineering of GRs, and pave the way for new developments and applications.Comment: 12 pages, 8 figures, 1 table. Three figures added; Sec. 3.3 significantly expande

Experimental evidence of guided resonances in photonic crystals with aperiodically-ordered supercells

We report on the first experimental evidence of guided resonances (GRs) in photonic crystal slabs based on aperiodically-ordered supercells. Using the Ammann-Beenker (quasiperiodic, 8-fold symmetric) tiling geometry, we present our study on the fabrication, experimental characterization, and full-wave numerical simulation of two representative structures (with different filling parameters) operating at near-infrared wavelengths (1300-1600 nm). Our results show a fairly good agreement between measurements and numerical predictions, and pave the way for the development of new strategies (based, e.g., on the lattice symmetry breaking) for GR engineering.Comment: 10 pages, 5 figures (minor revisions

Guided resonances in photonic crystals with point-defected aperiodically-ordered supercells

In this paper, we study the excitation of guided resonances (GRs) in photonic-crystal slabs based on point-defected aperiodically-ordered supercells. With specific reference to perforated-slab structures and the Ammann-Beenker octagonal lattice geometry, we carry out full-wave numerical studies of the plane-wave responses and of the underlying modal structures, which illustrate the representative effects induced by the introduction of symmetry-preserving and symmetry-breaking defects. Our results demonstrate that breaking the supercell mirror symmetries via the judicious introduction of point-defects enables for the excitation of otherwise uncoupled GRs, with control on the symmetry properties of their field distributions, thereby constituting an attractive alternative to those GR-engineering approaches based on the asymmetrization of the hole shape. In this framework, aperiodically-ordered supercells seem to be inherently suited, in view of the variety of inequivalent defect sites that they can offer.Comment: 13 pages, 12 figures, 1 table. Slight change in the title; major changes in the text and figure

Lab-on-fiber technology: a new avenue for optical nanosensors

The "lab-on-fiber" concept envisions novel and highly functionalized technological platforms completely integrated in a single optical fiber that would allow the development of advanced devices, components and sub-systems to be incorporated in modern optical systems for communication and sensing applications. The realization of integrated optical fiber devices requires that several structures and materials at nano- and micro-scale are constructed, embedded and connected all together to provide the necessary physical connections and light-matter interactions. This paper reviews the strategies, the main achievements and related devices in the lab-on-fiber roadmap discussing perspectives and challenges that lie ahead

Near-Field Opto-Chemical Sensors

Non

CONTRIBUTION TO THE STUDY OF THE CLIMATIC GEOGRAPHYOF CONTINENTAL ECUADOR

Climate is one of the most important aspects of geography, influencing many aspects of human life, from agriculture to tourism. Ecuador, given its geographical location and the presence of the Andes mountain range and the cold Humboldt Current has a variety of weather conditions and different types of climates. The objective of this research is to contribute to the study of Ecuadorian climatic geography, describing the main types of climates and their influence on vegetation, rainfall distribution and temperature, climatic phenomena, and other aspects of interest. In addition, an overview of the semi-arid pockets and some important climatic events occurring in the country is offered. The research was based on the search and selection of relevant and updated information related to the climatology of the afore mentioned nation; For this purpose, a variety of sources of information were obtained, including scientific articles, books, specialized journals and websites of official entities and organizations linked to the subject under analysis. It was found that the climatology of the Ecuadorian territory is diverse and complex, due, among other factors, to its geographical position and its geophysical configuration.El clima es uno de los aspectos más importantes de la geografía, ya que influye en muchos aspectos de la vida humana, desde la agricultura hasta el turismo. Ecuador, dada su ubicación geográfica, la presencia de la cordillera de Los Andes y la corriente fría de Humboldt dispone de una variedad de condiciones meteorológicas y diversos tipos de climas. El objetivo de esta investigación es contribuir al estudio de la geografía climática ecuatoriana, describiendo los principales tipos de clima y su influencia en la vegetación, la distribución de las lluvias y la temperatura, los fenómenos climáticos y otros aspectos de interés. Además, se ofrece una visión general de los bolsones semiáridos y algunos eventos climáticos importantes que ocurren en el país. La investigación se fundamentó en la búsqueda y selección de información relevante y actualizada relacionada con la climatología de la referida nación; a tales efectos se obtuvo una diversidad de fuentes de información, entre ellas, artículos científicos, libros, revistas especializadas y sitios web de entes oficiales y organizaciones vinculadas al tema objeto de análisis. Se encontró que la climatología del territorio ecuatoriano es diversa y compleja, debido entre otros factores, a su posición geográfica y su configuración geofísica

Nanophotonic sensors and AI for a new possible approach for accurate diagnosis of salivary glands tumors: a technical note

Currently, diagnosing salivary gland tumors in their early stages presents significant challenges. This paper aims to outline a feasibility analysis of a novel approach utilizing advanced nanophotonic sensors and AI to address these diagnostic issues. The proposed approach integrates new nanophotonic sensors to tackle the complexities encountered in the early detection of salivary gland tumors. By leveraging these cutting-edge sensors, we seek to offer a potential solution to the existing diagnostic problems associated with identifying these tumors at their initial stages