Publications by authors named "Ilaria Gallina"
Article Synopsis
- Recent studies show that placing metallic cut-wire arrays near a thin metallic screen can significantly improve the transmission of transverse-electric-polarized electromagnetic fields through small slits.
- This paper presents the first experimental proof of these enhancements using microwave measurements from printed-circuit-board prototypes.
- The experimental findings align closely with numerical predictions and demonstrate that the enhanced transmission remains effective despite potential fabrication errors or imperfections.
We report on the first experimental evidence of guided resonances (GRs) in photonic crystal slabs based on aperiodically ordered supercells. Using Ammann-Beenker (quasiperiodic, eightfold 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-IR 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 on, e.
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- - The paper compares the tuning efficiency and sensitivity of guided resonances in photonic crystal holed slabs, focusing on both periodic and aperiodic structures to evaluate their use in compact optical sensors and devices.
- - It specifically examines square-lattice periodic photonic crystals and Ammann-Beenker quasi-crystals, analyzing how factors like hole radius, slab thickness, and refractive index affect guided resonance performance.
- - The findings highlight that the arrangement of holes significantly impacts the tuning and sensitivity, suggesting new design possibilities for advanced photonic devices in sensing and telecommunications.
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.
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- - The paper presents the first evidence of guided resonances (GRs) in aperiodically-ordered photonic crystals, linking it to "quasicrystals" from solid-state physics.
- - Through numerical studies of a photonic quasicrystal (PQC) slab, the authors demonstrate that GR modes can be excited and analyze how they compare to those in periodic structures.
- - The findings suggest that GRs in PQCs result from coupling incident waves with degenerate modes and offer potential for new engineering opportunities and applications in photonic technologies.
Coordinate-transformation cloaking is based on the design of a metamaterial shell made of an anisotropic, spatially inhomogeneous "transformation medium" that allows rerouting the impinging wave around a given region of space. In its original version, it is generally believed that, in the ideal limit, the radiation cannot penetrate the cloaking shell (from outside to inside, and viceversa). However, it was recently shown by Chen et al.
View Article and Find Full Text PDFConventional methods to estimate the number of dentinal tubules cannot be considered reliable and repeatable, because results depends on the operator outlining of the tubules contours. In this study, we propose a totally automated computerized analysis technique to evaluate dentinal tubules and their surface area. The comparison test of these conventional with a semi-automatic methods shows that the automated analysis allowed a reliable identification and numbering of dentinal tubules, by means of high-quality images.
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