Universal lineshapes at the crossover between weak and strong critical coupling in Fano-resonant coupled oscillators

In this article we discuss a model describing key features concerning the lineshapes and the coherent absorption conditions in Fano-resonant dissipative coupled oscillators. The model treats on the same footing the weak and strong coupling regimes, and includes the critical coupling concept, which is of great relevance in numerous applications; in addition, the role of asymmetry is thoroughly analyzed. Due to the wide generality of the model, which can be adapted to various frameworks like nanophotonics, plasmonics, and optomechanics, we envisage that the analytical formulas presented here will be crucial to effectively design devices and to interpret experimental results

Coherent perfect absorption in photonic structures

The ability to drive a system with an external input is a fundamental aspect of light-matter interaction. The coherent perfect absorption (CPA) phenomenon extends to the general multibeam interference phenomenology the well known critical coupling concepts. This interferometric control of absorption can be employed to reach full delivery of optical energy to nanoscale systems such as plasmonic nanoparticles, and multi-port interference can be used to enhance the absorption of a nanoscale device when it is embedded in a strongly scattering system, with potential applications to nanoscale sensing. Here we review the two-port CPA in reference to photonic structures which can resonantly couple to the external fields. A revised two-port theory of CPA is illustrated, which relies on the Scattering Matrix formalism and is valid for all linear two-port systems with reciprocity. Through a semiclassical approach, treating two-port critical coupling conditions in a non-perturbative regime, it is demonstrated that the strong coupling regime and the critical coupling condition can indeed coexist; in this situation, termed strong critical coupling, all the incoming energy is converted into polaritons. Experimental results are presented, which clearly display the elliptical trace of absorption as function of input unbalance in a thin metallo-dielectric metamaterial, and verify polaritonic CPA in an intersubband-polariton photonic-crystal membrane resonator. Concluding remarks discuss the future perspectives of CPA with photonic structures.Comment: arXiv admin note: substantial text overlap with arXiv:1605.0890

Boa noite, Ana

TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Comunicação e Expressão. Cinema.N/

Liberalismo e tradizione cattolica. Osservazioni critiche su Juan de Marian

Many times the Jesuit Juan de Mariana (1535-1624) has been presented like a “communist”, or a “socialist”, or an “individualist”, a “classical liberal”, a “libertarian”, an “austrian economist”. The first consideration someone can do is all these traditions are very different each other and the second is that, apparently, they have few in common with catholic tradition. In this work the author tries to describe the complex intellectual world in which Juan de Mariana gave his contribution to economic thought, supposedly in the same line of the tradition of future Austrian Economics. In fact, according with recent studies of many authors, the prehistory of the Austrian School of Economics can be found in the works of the Spanish Scholastics, written in that historical period which is known as the “Spanish Golden Century” and ran from the mid-sixteenth century through the seventeenth century. According with Friedrich A. Hayek, some researches by Marjorie Grice- Hutchinson, Raymond de Roover and Murray N. Rothbard demonstrate that the basic principles of the theory of the competitive market were worked out by the Spanish Scholastics of the School of Salamanca and that economic liberalism was not designed by the Calvinists, but by the Spanish Jesuits. The works written by Alejandro Antonio Chafuen and Jesús Huerta de Soto stressed that perhaps the most libertarian of all the scholastics, particularly in his later works, was exactly Father Mariana. There is no dubt that Mariana has anticipated some important points of Austrian Economics, but is this enough to think about him like a libertarian? It’s possible to give two different answers to this question, both correct: the first one as an economist, and the second one as a historian of political thought

Improving the Protectiveness of 3-Mercaptopropyl-Trimethoxysilane Coatings on Bronze by Addition of Oxidic Nano- and Microparticles

The protectiveness of coatings based on 3-mercaptopropyl-trimethoxysilane (PropS-SH) applied on bronze artworks was enhanced by investigating and tuning a variety of factors. In particular, the coating performances were optimized by proper additive choice among oxide nanoparticles (CeO2, La2O3, TiO2) and microparticles (fly ash (FA)), and by varying the aging time of the nanoparticle suspensions before coating application and the RT curing time of the coatings. Moreover, the possibility of conservation of the silane solution under refrigerated conditions was assessed. The aggressive environment was a tenfold concentrated synthetic acid rain (AR × 10). The techniques adopted comprised electrochemical tests (polarization curve recording and EIS tests) and SEM-Energy Dispersion Spectroscopy (EDS) observations. In the case of FA microparticles, never used before as additives in silane coatings, further tests were performed in FA suspensions in AR × 10 to clarify the contribution of these particles to PropS-SH coating protectiveness. The tests included pH measurements, elemental chemical analyses, and electrochemical tests on bare bronze. Improved performances of PropS-SH coatings were achieved by La2O3, CeO2, and FA addition, with La2O3 affording the best results during 20 days of immersion. The positive influence of FA was connected to its alkaline character and to the release of soluble silicates