Nonlinear interactions between high-Q optical and acoustic modes in dielectric particles

The interaction between acoustic breathing modes and optical Mie resonances in a spherical particle made of a chalcogenide glass material is investigated by means of rigorous calculations, correct to any order in the acousto-optic coupling parameter. Our results reveal the occurrence of strong effects beyond the linear-response approximation, which lead to enhanced modulation of light by acoustic waves through multiphonon exchange mechanisms when both photons and phonons have a very long lifetime inside the particle

Organic.Edunet Web Portal: User Satisfaction Analysis

The Organic.Edunet Web portal is a multilingual federation of educational repositories, developed in order to enhance the availability and retrieval of quality educational resources about Organic Agriculture (OA) and Agroecology (AE). This paper presents the results of an online survey that took place from March to August 2010 in order to evaluate the user satisfaction from the Organic.Edunet Web portal. A standard methodology was followed in this survey, which was based on the WebQual questionnaire with the required modifications. The collected results were analyzed and statistically processed in order to lead to the corresponding conclusions

Absolute spectral gaps for infrared light and hypersound in three-dimensional metallodielectric phoxonic crystals

By means of full electrodynamic and elastodynamic multiple-scattering calculations we study the optical and acoustic properties of three-dimensional lattices of metallic nanospheres implanted in a dielectric host. Our results show that such structures exhibit omnidirectional spectral gaps for both telecom infrared light and hypersound, with relatively low absorptive losses. This class of dual phoxonic band-gap materials is an essential step toward the hypersonic modulation of light and could lead to the development of efficient acousto-optical devices

On maximal surfaces in the space of oriented geodesics of hyperbolic 3-space

We study area-stationary, or maximal, surfaces in the space ${\mathbb L}({\mathbb H}^3)$ of oriented geodesics of hyperbolic 3-space, endowed with the canonical neutral K\"ahler structure. We prove that every holomorphic curve in ${\mathbb L}({\mathbb H}^3)$ is a maximal surface. We then classify Lagrangian maximal surfaces $\Sigma$ in ${\mathbb L}({\mathbb H}^3)$ and prove that the family of parallel surfaces in ${\mathbb H}^3$ orthogonal to the geodesics $\gamma\in\Sigma$ form a family of equidistant tubes around a geodesic.Comment: 16 pages, AMS-Late

Stampacchia's property, self-duality and orthogonality relations

We show that if the conclusion of the well known Stampacchia Theorem, on variational inequalities, holds on a Banach space X, then X is isomorphic to a Hilbert space. Motivated by this we obtain a relevant result concerning self-dual Banach spaces and investigate some connections between existing notions of orthogonality and self-duality. Moreover, we revisit the notion of the cosine of a linear operator and show that it can be used to characterize Hilbert space structure. Finally, we present some consequences of our results to quadratic forms and to evolution triples