Optical transmission through single subwavelength apertures using prism coupled input of laser light of annular intensity profile

Light transmission through a single subwavelength aperture in a silver film is examined with a novel input configuration comprising an annular laser beam of variable diameter that is prism-coupled to the back face of the silver. Transmission peaks driven by excitation of the back-face surface plasmon mode or by the aperture resonance itself are separately observed. For both cases, comparison of films with and without a front-face, circular grating implies significantly more efficient coupling from the aperture fields to the front-face surface plasmon than directly to free radiation. (c) 2007 Optical Society of America.

Prism coupler with variable coupling gap

The construction and operation of a prism/variable-gap/sample system (or variable-gap Otto coupler) for the excitation of surface electromagnetic modes is reported. This system has been used for the observation and characterization of surface plasmon polaritons on thin film structures. The initial alignment of prism and sample is performed under gravity and the subsequent gap variation is performed by means of a single actuator operating a flexure stage on which the prism is mounted. The flexure stage ensures the maintenance of good parallelism between sample and prism as the gap dimension is varied. The coupler has also served as a prototype, in terms of design principle, for the construction of a more sophisticated, variable-gap Otto coupler that can operate in vacuum at temperatures from ambient to 85 K. (C) 2000 American Institute of Physics. [S0034-6748(00)02311-X].

Variable temperature, variable-gap Otto prism coupler for use in a vacuum environment

The field of surface polariton physics really took off with the prism coupling techniques developed by Kretschmann and Raether, and by Otto. This article reports on the construction and operation of a rotatable, in vacuo, variable temperature, Otto coupler with a coupling gap that can be varied by remote control. The specific design attributes of the system offer additional advantages to those of standard Otto systems of (i) temperature variation (ambient to 85 K), and (ii) the use of a valuable, additional reference point, namely the gap-independent reflectance at the Brewster angle at any given, fixed temperature. The instrument is placed firmly in a historical context of developments in the field. The efficacy of the coupler is demonstrated by sample attenuated total reflectance results on films of platinum, niobium, and yttrium barium copper oxide and on aluminum/gallium arsenide (Al/GaAs) Schottky diode structures. (C) 2000 American Institute of Physics. [S0034-6748(00)02411-4].

Reviewing the European North/South Divide under the Prism of Beck’s ‘Risk society’ Thesis

Reviewing the European North/South Divide under the Prism of Beck’s ‘Risk society’ Thesis
Southern European political cultures have been viewed as extremely disadvantageous terrains for the development of a civic culture compatible to the requirements of a modern polity. Trust confined to the local and the familial, weak civil societies, violation of the law in the absence of supervision are some of the elements combined to draw an extremely negative picture of southern European political cultures in the relevant literature. These are very well entrenched perceptions that dominate all studies dealing with social aspects the southern European nations. Recent works produced by students of environmental mobilisations have argued that the environmental problematique has operated as a catalyst that, at least, forces us to re-examine the aforementioned perspectives if not to outright dismiss them.

This paper argues that although these challenging perspectives are not immune from criticisms, they have put forward a strong case that deserves further attention. A careful reading of Beck’s ‘risk society’ thesis suggests that mistrust to expert authorities and defensive reactions by social actors against them are not confined to specific national contexts but are now characteristics of countries previously held to be exemplary cases of civicness. Following that observation the paper proceeds by posing a number of related questions:

1) Can we argue that we are witnessing a general ‘Mediterranisation’ of European political culture or by arguing that we essentially accept what was idealistic evaluations of post-war European cultures determined by specific political conceptions?

2) Is there still any role for the use of a north/south divide in the cross-national study of social processes and to what extent?

Philorhomaioi: The Herodian Prism

This paper offers a reconstruction and analysis of the Herodian family as a presence in the city of Rome over more than three generations. The scholarly tendency to view the Herods as an aspect of a broader governmental system overlooks the workings of the particular relationships that elevated the Herods in their own land as well as at the centre of Roman power. Beginning with the foundation of a lasting connection between the Herods and the Julio-Claudians laid by Herod the Great and Augustus, this paper traces the legacy of that connection and its impact on affairs in both Judaea and Rome. The peculiar challenges of retaining status in both Roman and Jewish contexts are assessed and their importance as a vital aspect of our understanding of first-century Judaean politics is established. Examination, finally, of the development of their aspirations and their negotiation of dynastic change shows vividly the processes of ‘Romanisation’ in the context of an elite family.

Surface energy and surface proton order of the ice Ih basal and prism surfaces

Density-functional theory (DFT) is used to examine the basal and prism surfaces of ice Ih. Similar surface energies are obtained for the two surfaces; however, in each case a strong dependence of the surface energy on surface proton order is identified. This dependence, which can be as much as 50% of the absolute surface energy, is significantly larger than the bulk dependence (< 1%) on proton order, suggesting that the thermodynamic ground state of the ice surface will remain proton ordered well above the bulk order-disorder temperature of about 72 K. On the basal surface this suggestion is supported by Monte Carlo simulations with an empirical potential and solution of a 2D Ising model with nearest neighbor interactions taken from DFT. Order parameters that define the surface energy of each surface in terms of nearest neighbor interactions between dangling OH bonds (those which point out of the surface into vacuum) have been identified and are discussed. Overall, these results suggest that proton order-disorder effects have a profound impact on the stability of ice surfaces and will most likely have an effect on ice surface reactivity as well as ice crystal growth and morphology. S Supplementary data are available from stacks.iop.org/JPhysCM/22/074209/mmedia

Risk versus National Pride. Conflicting discourses over the construction of a High Voltage Power Station in the Athens Metropolitan Area for demands of the 2004 Olympics

This paper first explores the conflictual discourses employed by government agencies, citizens’ initiatives, and environmental organizations over the construction of a High Voltage Power Station (KYT) for demands of the 2004 Olympic Games, as presented in media reports and movement literature over a period of one year. Having in mind recent criticisms targeting the lack of empirical evidence in Ulrich Beck’s risk theorization, this exploration is of distinct importance. Secondly, it takes into account that both the defensive character of societal action and mistrust to expert authorities have been confirmed as prevalent characteristics of both the Greek and the general risk social context. The paper attempts to re-evaluate and/or complement existing perspectives of societal activism in general and environmental mobilizations in particular within the confines of the Greek social context. As a tentative conclusion, it is suggested that the risk perspective offers a novel prism for the examination of societal activism without confining it to the characteristics of individual national contexts.

Surface plasmon polariton propagation length: A direct comparison using photon scanning tunneling microscopy and attenuated total reflection

The propagation of surface plasmon polaritons (SPP's) is studied using a photon scanning tunneling microscope (PSTM) and conventional attenuated total reflection (ATR). The PSTM experiment uses localized (focused beam) launching or SPP's at a wavelength of 632.8 nm. Propagation of the SPP is observed as an exponentially decaying tail beyond the launch site acid the 1/e propagation length is measured directly for a series of Ag films of different thicknesses. The ATR measurements are used to characterize the thin film optical and thickness parameters, revealing, notably, the presence of a contaminating adlayer of Ag2S of typical dielectric function, 8.7 + i2.7, and thickness 1-2 nm. Values of the SPP propagation length, based on the ATR- derived film parameters used in the four-media implicit SPP dispersion relation, show very good agreement with those based on the PSTM images for the case of undercoupled or optimally coupled SPP modes. The observed propagation lengths are quantitatively analyzed taking explicit account of additional intrinsic damping due to the growth of the Ag2S layer and of reradiation of the SPP back into the prism outside the launch site. Finally, the PSTM images show excellent SPP beam confinement in the original propagation direction.

Surface plasmon polariton propagation across a gentle silver step

Surface plasmon polaritons (SPPs) are excited with light of wavelength lambda (1) = 632.8 nm on or near a gentle Ag/Ag step structure using focused beam, prism coupling and detected using a bare, sharpened fibre tip. The tip-sample separation is controlled by means of an evanescent optical field at wavelength lambda (2) = 543.5 nm in a photon scanning tunnelling microscope (PSTM). The SPP propagation properties are first characterised on both the thin and thick sections of the Ag film structure either side of the step, both macroscopically, using attenuated total reflection, and microscopically from the PSTM images; the two techniques yield very good agreement. It is found that the SPP propagation length is similar to 10-11 mum across the step in each direction (thick to thin and vice versa) as observed in the PSTM images. Thus, with reference to the propagation lengths of 14.2 and 11.7 mum for the thick and thin planar parts of the Ag film respectively, it is concluded that the SPPs negotiate the step reasonably successfully. Importantly, also, it is shown that images may be produced, displaying SPPs with either an artificially enhanced (similar to 15-20 mum) or truncated (5-8 mum) propagation length across the step. Consideration of such images leads us to suggest the possibility that the photon tunnelling occurs in a local water environment. (C) 2001 Elsevier Science B.V. All rights reserved.

Measurement and interpretation of the mid-infrared properties of single crystal and polycrystalline gold

The contribution of electron-phonon scattering and grain boundary scattering to the mid-IR (lambda = 3.392 mum) properties of An has been assessed by examining both bulk, single crystal samples-Au(1 1 1) and Au(1 1 0)-and thin film, polycrystalline An samples at 300 K and 100 K by means of surface plasmon polariton excitation. The investigation constitutes a stringent test for the in-vacuo Otto-configuration prism coupler used to perform the measurements, illustrating its strengths and limitations. Analysis of the optical response is guided by a physically based interpretation of the Drude model. Relative to the reference case of single crystal Au at 100 K (epsilon = - 568 + i17.5), raising the temperature to 300 K causes increased electron-phonon scattering that accounts for a reduction of similar to40 nm in the electron mean free path. Comparison of a polycrystalline sample to the reference case determines a mean free path due to grain boundary scattering of similar to 17 nm, corresponding to about half the mean grain size as determined from atomic force microscopy and indicating a high reflectance coefficient for the An grain boundaries. An analysis combining consideration of grain boundary scattering and the inclusion of a small percentage of voids in the polycrystalline film by means of an effective medium model indicates a value for the grain boundary reflection coefficient in the range 0.55-0.71. (C) 2005 Elsevier B.V. All rights reserved.

Molecular Modeling on Inhibitor Complexes and Active-Site Dynamics of Cytochrome P450 C17, a Target for Prostate Cancer Therapy

A molecular model for the P450 enzyme cytochrome P450 C17 (CYP17) is presented based on sequence alignments of multiple template structures and homology modeling. This enzyme plays a central role in the biosynthesis of testosterone and is emerging as a major target in prostate cancer, with the recently developed inhibitor abiraterone currently in advanced clinical trials. The model is described in detail, together with its validation, by providing structural explanations to available site-directed mutagenesis data. The CYP17 molecule in this model is in the form of a triangular prism, with an edge of similar to 55 angstrom and a thickness of similar to 37 angstrom. It is predominantly helical, comprising 13 alpha helices interspersed by six 3(10) helices and 11 beta-sheets. Multinanosecond molecular dynamics simulations in explicit solvent have been carried out, and principal components analysis has been used to reveal the details of dynamics around the active site. Coarse-grained methods have also been used to verify low-frequency motions, which have been correlated with active-site gating. The work also describes the results of docking synthetic inhibitors, including the drug abiraterone and the natural substrate pregnenolone, in the CYP17 active site together with molecular dynamics simulations on the complexes. (C) 2010 Elsevier Ltd. All rights reserved.

New and Alternative Social Movements in Spain: The Left, Identity and Globalizing Processes

This collection offers a diachronic analytical study of new and alternative social movements in Spain from the democratic transition to the first decade of the 21st century, paying attention to anti-war mobilizations and the use of new technologies as a mobilizing resource. New and alternative social movements are studied through the prism of identified linkages among the left, movement identities and global processes in the Spanish context. Weight is given to certain important historical aspects, like Spain’s relatively recent authoritarian past, and certain value-added factors, such as the weak associationalism and materialism exhibited by the Spanish public. These are complemented by exploring insights offered by key theoretical approaches on social movements (political opportunities structures, resource mobilization). The volume covers established social movement cases (gender, peace, environmental movements) as well as those with a more explicit connection to the current context of global contestation (squatters’ and anti-globalization movements).

Challenging the SD benefits attributed to sport Mega-Events hosting

Sport Mega-event hosting faces opposition that is manifested with different intensity during the different phases of the event, from its inception as an idea to its delivery and legacy. Some Social Movements Organisations (SMOs) have acted as indefatigable monitors of the Sustainable Development (SD) dimension of sporting events in general and, in some of the most recent sport mega-events, in particular the Olympics, they have served as important advisors and facilitators. Nevertheless, in many cases we see enthusiastic supporters turning to vehemently challenging whatever positives have been associated with hosting the event. In addition, there is opposition to sport Mega-events in their entirety. That type of opposition tends to employ a holistic prism that manages to identify multiple interconnected negative aspects of hosting a sport mega-event and incorporate them into an anti-systemic discourse. It is important to bear in mind that irrespective of many proclamations to the opposite as far as megas are concerned (projects and/or events), a number of studies have demonstrated that citizen participation and democratic accountability in decision-making have been notoriously absent. After all, the idea of citizen participation in the planning of sport mega-event is essentially the public response to a plan conceived by others. There were, of course, some notable cases of democratic consultation at the early stages of bidding to host a sport mega-event but these more democratic approaches resulted in the failure of the bid (for e.g. Toronto 1996). The knowledge of this by the groups that initiated the hosting idea and the bidding process has led to discouraging in depth public consultation that may fit perfectly to the democratic process but not to the tight schedules of associated projects completion. That produces ‘autocracy against which opposition may arise’ (Hiller, 2000, p. 198). It is this democratic deficit that has led to important instances of social contestation and protest mobilizations by citizen groups as well as the more regular corps of social activists. From a perspective borrowed from the sociology of protest and social movements, sport mega-events hosting can operate as an issue that stimulates protest activities by an existing protest milieu and new actors as well as an important mobilizing resource. In fact, some scholars have also argued that the Olympic Games were an important frame for the transnational activism that was marked by anti-globalization protest in Seattle in 1999 (Cottrell & Nelson, 201; Lenskyj, 2008). In addition, it’s important not to lose sight of other acts dissent that take place in relatively close proximity, about a year before the event when most infrastructural and societal changes brought by hosting the event and impact start to become apparent by the host communities, like the rioting of August 2011 in the London Olympic Boroughs and the 2012 riots of June 2013 in Sao Paulo and other Brazilian cities. This paper starts by outlining the SD claims made in the bidding to host the summer Olympic Games by five prospective hosts (Sydney; Athens; Beijing; London and Rio) proceeds towards examining the opposition and challenges that was manifested in relation to these claims. In Particular it provides an assessment of protest-events over the aforementioned different phases of sport mega-events hosting. A different picture emerges for each of the host nation that is partly explained by local, national and global configuration of protest politics. Whereas the post-event legacy of the first two hosts of the Games can be assessed and that way see the validity of claims made by challengers in the other phases, in the other three cases, the implementation of Olympic Games Impact (OGI) studies offers the tool for discussing the post-event phase for Beijing and London and engage in a speculative exercise for the case of Rio. Judging by available findings, the paper concludes that the SD aspiration made in the bid documents are unlikely to be met and social contestation based on the same issues is likely to increase due to the current global economic crisis and BRICS, like China and Brazil, having entered the process of becoming global economic hegemons.

The interaction of surface plasmon polaritons with a silver film edge

A prism coupling arrangement is used to excite surface plasmons at the surface of a thin silver aim and a photon scanning tunnelling microscope is used to detect the evanescent field above the silver surface. Excitation of the silver/ air mode of interest is performed at lambda(1) = 632 . 8 nm using a tightly focused beam, while the control of the tip is effected by exciting a counter-propagating surface plasmon field at a different wavelength. lambda(2) = 543 . 5 nm, using an unfocused beam covering a macroscopic area. Propagation of the red surface plasmon is evidenced by an exponential tail extending away from the launch site, but this feature is abruptly truncated if the surface plasmon encounters the edge of the silver film - there is no specularly reflected 'beam'. Importantly, the radiative decay of the surface mode at the film edge is observable only at larger tip-sample separations, emphasizing the importance of accessing the mesoscopic regime.

Application of surface plasmon polaritons in the laser ablation and characterisation of thin aluminium films

Surface modification of thin aluminium films is both produced and characterised by exciting surface plasmon polaritons in an attenuated total reflection geometry: silica prism/aluminium/aluminium oxide system. The modification is performed, under ambient conditions, by exposure to a low fluence (