Nanocircuit Loading of Plasmonic Waveguides

We apply the optical nanocircuit concepts to model and design optical nanofilters in realistic plasmonic waveguides of different nature, including strips and groove waveguides. The nanocircuit elements are designed to fit the waveguide geometry, and its equivalent impedance is analytically calculated by substituting the role of the conduction current with displacement current. The effect of plasmonic waveguide walls is rigorously modeled in terms of an extra nanocircuit loading that is included in our model.We show via numerical results that the nanocircuit approachmay be effectively applied to the design of nanofilters, analogous to familiar concepts at radio-frequencies

Migration-aware policy-making in decentralised and dynamic social and collaborative environments

Migration for employment is acknowledged to have direct consequences on National economies, as well as the overall economic situation of the European Union (EU). Migration policy and decision-makers need to systematically collaborate towards sophisticated approaches that facilitate legal immigrants to be effectively integrated in labour markets and public administration processes. Latest ICT developments, which integrate Web 2.0 technologies, collaborative knowledge management systems, and semantic analysis technologies, allow participatory governance and citizen-generated policy making. This paper presents a collaborative migration policy-modelling centre, techniques, solutions and overall services for collaborative development of immigration policies, as well as for supporting related decisions. © Copyright 2011 Inderscience Enterprises Ltd

Guidance Properties of Plasmonic Nanogrooves: Comparison Between the Effective Index Method and the Finite Integration Technique

In this letter, we compare the effective index method (EIM), applied to derive an analytical model of the guidance properties of plasmonic groove waveguides, to full-wave simulations based on finite integration technique (FIT). We apply our results to different plasmonic groove geometries, with particular attention to the triangular (V-groove) waveguide. We first approximate the V-groove geometry with a multiple-sections rectangular-stepped waveguide, for which EIM may be applied in closed form. Explicit formulas for the dispersion properties are given in terms of a set of transcendental equations, which are then solved with standard numerical complex-zeros-searching routines. Our numerical results are then compared and validated with FIT full-wave simulations, showing the range of validity of EIM and providing an efficient analytical description and physical insights into the guided propagation in V-groove plasmonic waveguides

A user-centric and federated Single-Sign-On IAM system for SOA e/m-frameworks

Nowadays, the need for more user-centric privacy-aware transactions raises specific challenges that Service Oriented Architectures (SOA) need to address, including the problems of managing users' personal identification information and ensuring privacy and anonymity in the e/m-environment. This paper presents a targeted, user-centric and federated Single-Sign-On Identity Management System (IAM) called SecIdAM, and a mobile implementation framework for building privacy-aware, interoperable and secure mobile applications with respect to the way that the trust relationship among the involved entities, users and SOAs is established. Moreover, it analyses a usertransparent m-process, simulating the registration, negotiation of policies and identification information preferences, and user's authorisation sessions, as integrated in the IST European programme SWEB for the public sector. Copyright © 2010 Inderscience Enterprises Ltd

Dispersion Characteristics in Disk-on-Pillar Array Nanostructures for Surface-Enhanced Raman Spectroscopy

In this paper, we analyze periodic disk-on-pillar nanoarrays as a platform for surface-enhanced Raman spectroscopy measurements. The nanostructure is a two-dimensional grating of silicon pillars covered by thin layers of silica and silver. The system supports both localized surface plasmons and surface plasmon polaritons. We investigate the dispersion characteristics of the nanoarray and present the relevant field distribution for each plasmon mode. The interaction between localized and propagating modes can be tuned to synergistically enhance the electric field, which results in larger surface-enhanced Raman signals. We find that utilizing this effect can generate Raman enhancements that are approximately 1000 times larger than that of an isolated pillar under the same excitation conditions

Efficient disc on pillar substrates for surface enhanced Raman spectroscopy

In this work, geometrical optimizations of Ag disc on pillar (DOP) hybrid plasmonic nanostructures were conducted and allowed us to achieve reproducible average enhancement factors of 1 x 10(9) and greate

Local Field Enhancement of Pillar Nanosurfaces for SERS

Optical spectra and atomic force microscopy (AFM) images of individually selected spheres and mechanically assembled silica-coated gold nanosphere pairs were recorded. The shell served as a means of rigid control of the minimum spacing between the metal cores. The spectra of the assembled spheres were simulated using classical electrodynamics. The observed spectra resulted in superior characterization of the particle assembly geometry, relative to the AFM data. Experimental investigations regarding less-rigid polyvinylpyrrolidone (PVP) sphere coatings were also performed and some comparisons were made