4,841 research outputs found
A review of geometry representation and processing methods for cartesian and multiaxial robot-based additive manufacturing
Nowadays, robot-based additive manufacturing (RBAM) is emerging as a potential solution to increase manufacturing flexibility. Such technology allows to change the orientation of the material deposition unit during printing, making it possible to fabricate complex parts with optimized material distribution. In this context, the representation of parts geometries and their subsequent processing become aspects of primary importance. In particular, part orientation, multiaxial deposition, slicing, and infill strategies must be properly evaluated so as to obtain satisfactory outputs and avoid printing failures. Some advanced features can be found in commercial slicing software (e.g., adaptive slicing, advanced path strategies, and non-planar slicing), although the procedure may result excessively constrained due to the limited number of available options. Several approaches and algorithms have been proposed for each phase and their combination must be determined accurately to achieve the best results. This paper reviews the state-of-the-art works addressing the primary methods for the representation of geometries and the subsequent geometry processing for RBAM. For each category, tools and software found in the literature and commercially available are discussed. Comparison tables are then reported to assist in the selection of the most appropriate approaches. The presented review can be helpful for designers, researchers and practitioners to identify possible future directions and open issues
Towards all-dielectric metamaterials and nanophotonics
We review a new, rapidly developing field of all-dielectric nanophotonics
which allows to control both magnetic and electric response of structured
matter by engineering the Mie resonances in high-index dielectric
nanoparticles. We discuss optical properties of such dielectric nanoparticles,
methods of their fabrication, and also recent advances in all-dielectric
metadevices including couple-resonator dielectric waveguides, nanoantennas, and
metasurfaces
Silicon Nanoantenna Mix Arrays for a Trifecta of Quantum Emitter Enhancements
Dielectric nanostructures have demonstrated optical antenna effects due to
Mie resonances. Preliminary investigations on dielectric nanoantennas have been
carried out for a trifecta of enhancements, i.e., simultaneous enhancements in
absorption, emission directionality and radiative decay rates of quantum
emitters. However, these investigations are limited by fragile substrates or
low Purcell factor, which is extremely important for exciting quantum emitters
electrically. In this paper, we present a Si mix antenna array to achieve the
trifecta enhancement of ~1200 fold with a Purcell factor of ~47. The antenna
design incorporates ~10 nm gaps within which fluorescent molecules strongly
absorb the pump laser energy through a resonant mode. In the emission process,
the antenna array increases the radiative decay rates of the fluorescence
molecules via Purcell effect and provides directional emission through a
separate mode. This work could lead to novel CMOS compatible platforms for
enhancing fluorescence for biological and chemical applications.Comment: 20 pages, 4 figure
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