Prisme (optique)

Résumé

vignette|upright=1.5|Trois prismes à base triangulaire : un prisme à angle droit, un prisme à 60° et un prisme à 30°.|alt=Photographie de trois prismes en verre posés sur une table en bois. Un prisme est un bloc de verre taillé, composé classiquement de trois faces sur une base triangulaire, mais qui peut adopter des formes plus complexes et éloignées du prisme à base triangulaire usuel. C'est un instrument optique utilisé pour réfracter la lumière, la réfléchir ou la disperser. Des prismes spéciaux peuvent aussi servir à diffracter la lumière, la polariser ou en séparer les polarisations ou encore créer des interférences. Utilisé dans l'Antiquité pour son côté décoratif, sous forme de perles ou pour décomposer la lumière, le prisme connaît son premier essor comme instrument scientifique durant le Moyen Âge tardif. Il a permis de grandes avancées dans la compréhension de la composition de la lumière grâce aux expériences d'Isaac Newton au . Depuis, les prismes ont été utilisés majori

Source officielle

https://fr.wikipedia.org/wiki/Prisme_(optique)

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PRISMS: An Integrated, Open-Source Framework for Accelerating Predictive Structural Materials Science

Zhouji Huang, Lin Qi, Zheng Wang

The Center for Predictive Integrated Structural Materials Science (PRISMS Center) is creating a unique framework for accelerated predictive materials science and rapid insertion of the latest scientific knowledge into next-generation ICME tools. There are three key elements of this framework. The first is a suite of high-performance, open-source integrated multi-scale computational tools for predicting microstructural evolution and mechanical behavior of structural metals. Specific modules include statistical mechanics, phase field, crystal plasticity simulation and real-space DFT codes. The second is the Materials Commons, a collaboration platform and information repository for the materials community. The third element of the PRISMS framework is a set of integrated scientific “Use Cases” in which these computational methods are linked with experiments to demonstrate the ability for improving our predictive understanding of magnesium alloys, in particular, the influence of microstructure on monotonic and cyclic mechanical behavior. This paper reviews progress toward these goals and future plans.

Springer Nature2018

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Experimental verification of the method for producing a three-dimensional cross-pairs metamaterial structure based on a dielectric AlN cube

Przemyslaw Andrzej Gorski

This paper presents a method of manufacturing 3D metamaterial structures using laser radiation. Our proposed material, aluminum nitride (AlN), by interaction of a high-energy laser beam undergoes a direct metallization process, a result of which a conductive aluminum layer is formed on the ceramic surface at the spot of the laser radiation. Using this unique feature on all six sides of an AlN ceramic cube, the designed cross-pairs were mapped. Unit cells were exposed to an electromagnetic wave, by which the occurrence of the resonant areas of reflectance and transmittance for 7.27 GHz and 9.14 GHz was observed. To demonstrate the property of the negative refractive index a prism made out of manufactured cubes was created. For a wave propagating through a wedge-shaped prism for certain frequency bands, a negative refraction angle was observed.

Iop Publishing Ltd2016

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Amazing and beautiful optical effects are present in Nature. Some examples are the iridescent colors produced by peacocks, butterflies and beetles. While the simulations of some of these structures have already been realized, only a few elements have been fabricated. We are interested to understand and to reproduce some of these amazing optical properties. Applications such as security or decorative elements in different fields like jewelery or horology can be imagined. SEM pictures of the structure of these animals show a frequent combination of periodic or pseudo-periodic elements such as interference filters, multilayer reflectors, microlenses and gratings. The different elements combine angular and spectral effects. This combination enables strong optical effects for a large range of viewing angles and spectra. Different technologies such as standard photolithography, recording of interference patterns, transfer of photoresist structures in glass substrates, replications, hot embossing and spincoating were used to fabricate a variety of optical elements. The fabricated elements were produced with polymer materials because of their ease of use, and the possibility to build multilevel structures with replication methods. A drawback is the small refractive index difference possible between polymers and compared to air. In the first part, different combinations of polymer micro- and nano-optical elements such as corrugated gratings, multilayer Bragg reflectors, microlens arrays, micro-prisms arrays and diffusers were successfully fabricated. Poly (vinyl alcohol) and poly (N-vinycarbazole) with refractive indices of 1.56 and 1.72, respectively, at a wavelength of 500nm were used to fabricate the polymer multilayer reflectors. The micro-optical elements used were: microlenses with diameter between 32 μm and 250 μm and around 20 μm height; prisms with 50 μm period and 25 μm height. The angularly dependent reflectivity of the different fabricated elements was studied. Thanks to the close combination of diffractive, refractive and reflective micro- and nano-optical elements, non-standard artificial visual color effects were produced. The fabricated elements were modeled with different tools according to the dimensions of the different optical elements. Ray tracing analysis was used in the case with micro-optical elements while the Fourier modal method permitted simulation of the interaction of the light with the periodic nano-structures. The specific effects of the variation of the different parameters were highlighted, the basic principles and the limitation of the polymer technology were identified. In the second part, the optical modeling tools and the fabrication technologies developed were used to model and fabricate polymer light emitting diodes in a distributed feedback regime. The optical properties of the different layers were modeled and the physical dimensions of elements with active conductive polymers me-LPPP and F8 were calculated, fabricated and tested. The sensitive dimensions and parameters were underlined. Polymer materials permitted rapid fabrication of complex and innovative optical elements with very simple technologies like spin-coating and replication methods. These technologies allow the combination of nano-optical elements with dimensions of the order of a hundred nanometers with micro-optical elements with dimension of the order of about ten to one hundred microns.

Institut de Microtechnique, Université de Neuchâtel2008

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Institut de Microtechnique, Université de Neuchâtel2008