Search results for "polarization [Upsilon(9460)]"
showing 10 items of 915 documents
Oblique incidence and polarization effects in coupled gratings.
2012
Oblique incidence and polarization orientation of the input beam have dramatic effects on the spectral response of coupled dielectric waveguide gratings. Coupled gratings with small periodic perturbations can be described as a problem of two coupled resonances at strictly normal incidence, but we find that the device involves four coupled resonances when oblique incidence and polarization effects are included in the analysis. Very small deviations from normal incidence change qualitatively the spectral response and four peaks are observed, whereas only two peaks are present at normal incidence. Polarization misalignments produce a decrease of the reflectance of the resonances at normal inci…
Excitation of a one-dimensional evanescent wave by conical edge diffraction of surface plasmon
2011
International audience; The experimental observation of a one-dimensional evanescent wave supported by a 90◦ metal edge is reported. Through a measurement of in-plane momenta, we clearly demonstrate the dimensional character of this surface wave and show that it is non-radiative in the superstrate. Excitation conditions, lateral extension and polarization properties of this wave are discussed. Finally, we explore the effect of the surrounding dielectric medium and demonstrate that a single edge can sustain distinct excitations.
Asymmetric transmission of transverse magnetic or radially polarized THZ waves through sub-wavelength gratings
2015
We have developed a metallic double circular grating with sub-wavelength slits which blocks radially polarized light incident from one of its sides and acts as a focusing diffractive element in the other direction. The proposed grating has been optimized for the sub-THz frequency range. Unidirectional transmission through the grating has been demonstrated experimentally at 0.1 THz. We have also developed a planar metallic double grating with sub-wavelength slits which blocks light with a transverse magnetic polarization incident from one of the grating sides and transmits radiation incident from the opposite direction into the +1 and −1 diffraction orders. These gratings which could be used…
Super-resolved or field of view enlarged imaging based upon spatial depolarization of light
2010
Abstract In this paper we present a new approach allowing the surpassing of the diffraction based limitation for the achievable resolution provided by imaging systems. It is based on an encoding–decoding process of various spatial pixels or regions in the field of view of the imaged object by orthogonal and differently time varying polarization states. The reconstruction of the original spatial information is obtained by applying a decoding process in a way similar to the encoding one. Although all the spatial information is summed and mixed together by the system, the decoding provides super-resolved imaging since in every spatial position the undesired spatial information having time vary…
ASSESMENT OF TEMPERATURE POLARIZATION IN MEMBRANE DISTILLATION CHANNELS BY LIQUID CRYSTAL THERMOGRAPHY
2014
AbstractThe measurement of local temperature distributions within a membrane distillation (MD) channel is a crucial step for the optimization of the channel and spacer geometry. This information allows the estimation of temperature polarization phenomena, which can dramatically influence the thermal efficiency of the process and the optimal choice of the geometric configuration (net spacer features, channel size, etc.). In the present work, a recently presented experimental technique, based on the use of thermochromic liquid crystals and digital image analysis, has been employed in order to assess the temperature polarization phenomena. The local heat transfer coefficient distribution on th…
Long-lived dynamic heterogeneity in a relaxor ferroelectric
1998
The polydispersive dielectric response of the relaxor ferroelectric lead magnesium niobate was investigated using nonresonant spectral hole-burning experiments. Using large alternating electric fields, specific parts of the relaxation-time distribution could be addressed selectively. This provides evidence for the dynamic heterogeneity of the dipolar reorientation process. The refilling of single as well as of double holes was much slower than the time scale set by the pump frequencies. Upon refilling, the holes exhibited no signs of spectral broadening. The present findings suggest a speedup of polarization response associated with a domain-wall depinning that is induced by the hole-burnin…
Getting support in polarized societies: Income, social networks, and socioeconomic context
2013
AbstractThis paper explores how unequal resources and social and economic polarization affects the size of social networks and their use to access resources. We argue that individual resource position generates divergent expectations with regard to the impact of polarization on the size of networks on one hand, and their usefulness for accessing resources on the other. Social and economic polarization encourages reliance on informal networks, but those at the bottom of the social structure are forced to rely on more extensive networks than the wealthy to compensate for their isolated and underprivileged position. At the same time, social and economic polarization limits the resources the po…
Spatial Convergence Clubs and the European Regional Growth Process,1980–1995
2003
In international cross-country studies, evidence for club convergence has often been found using different methodologies (Baumol 1986; Durlauf and Johnson 1995; Quah 1996a, 1997). In the case of the European regions, Ertur and Le Gallo (see Chap. 2) and Le Gallo et al. (see Chap. 3) have shown that the convergence rate among European regions is slow and that GDP disparities seem to be persistent despite the European economic integration process and higher growth rates of some poorer regions, as highlighted as well in the European Commission reports (1996, 1999). Moreover, over the 1980–1995 period, Ertur and Le Gallo (see Chap. 2) found that the geographical distribution of European regions…
Productivity Polarization and Sectoral Dynamics in European Regions
2007
Abstract We show that the distribution dynamics of productivity in European regions displays polarization with a nonlinear growth path. We investigate the factors explaining this behavior focusing in particular on sectoral composition. The β -convegence analysis reveals that initial shares of Manufacturing and Other Market Services have a nonlinear impact on growth, while spatial effects are not statistically significant. By decomposing the dynamics of aggregate productivity in terms of sectoral dynamics, we show that productivity in Manufacturing, Non Market Services, and Other Market Services does not converge, for the complex interaction of technological spillovers and specialization eff…
Clustering and Polarization in the Distribution of Output: A Multivariate Perspective.
2013
Abstract Modeling the cross-country distribution of per capita income using mixture analysis provides a natural platform for the detection of clubs of countries. Unfortunately, these mixture methods, when based on a strictly univariate approach are limiting towards one’s ability to learn about the underlying process of the emergence of what constitutes a club. This paper takes a fresh look at the constitution of the emerging clubs in the distribution of cross-country output using bivariate and multivariate mixture analysis. Our results suggest that clubs are also forming in the main Solowian determinants of economic growth.