Optical tweezers with enhanced efficiency based on laser-structured substrates

We present an optical nanotrapping setup that exhibits enhanced efficiency, based on localized plasmonic fields around sharp metallic features. The substrates consist of laser-structured silicon wafers with quasi-ordered microspikes on the surface, coated with a thin silver layer. The resulting optical traps show orders of magnitude enhancement of the trapping force and the effective quality factor

Real-time observation of a coherent lattice transformation into a high-symmetry phase

Excursions far from their equilibrium structures can bring crystalline solids through collective transformations including transitions into new phases that may be transient or long-lived. Direct spectroscopic observation of far-from-equilibrium rearrangements provides fundamental mechanistic insight into chemical and structural transformations, and a potential route to practical applications, including ultrafast optical control over material structure and properties. However, in many cases photoinduced transitions are irreversible or only slowly reversible, or the light fluence required exceeds material damage thresholds. This precludes conventional ultrafast spectroscopy in which optical excitation and probe pulses irradiate the sample many times, each measurement providing information about the sample response at just one probe delay time following excitation, with each measurement at a high repetition rate and with the sample fully recovering its initial state in between measurements. Using a single-shot, real-time measurement method, we were able to observe the photoinduced phase transition from the semimetallic, low-symmetry phase of crystalline bismuth into a high-symmetry phase whose existence at high electronic excitation densities was predicted based on earlier measurements at moderate excitation densities below the damage threshold. Our observations indicate that coherent lattice vibrational motion launched upon photoexcitation with an incident fluence above 10 mJ/cm2 in bulk bismuth brings the lattice structure directly into the high-symmetry configuration for tens of picoseconds, after which carrier relaxation and diffusion restore the equilibrium lattice configuration.Comment: 22 pages, 4 figure

E-Democracy and the European Public Sphere

The chapter starts with an outline of outstanding recent contributions to the discussion of the EU democratic deficit and the so-called “no demos” problem and the debate about European citizenship and European identity—mainly in the light of insights from the EU crisis. This is followed by reflections on the recent discussion on the state of the mass media-based European public sphere. Finally, the author discusses the state of research on the Internet’s capacity to support the emergence of a (renewed) public sphere, with a focus on options for political actors to use the Internet for communication and campaigning, on the related establishment of segmented issue-related publics as well as on social media and its two-faced character as an enabler as well as a distorting factor of the public sphere. The author is sceptic about the capacities of Internet-based political communication to develop into a supranational (European) public sphere. It rather establishes a network of a multitude of discursive processes aimed at opinion formation at various levels and on various issues. The potential of online communication to increase the responsiveness of political institutions so far is set into practice insufficiently. Online media are increasingly used in a vertical and scarcely in a horizontal or interactive manner of communication

GREECE. Critical junctures in the media transformation process.

The present study seeks to identify risks and opportunities for deliberative communication in Greece and to flag critical junctures in the development of the media between 2000 and 2020 across the four domains covered by the MEDIADELCOM project: a) legal and ethical regulation, b) journalism, c) media usage patterns, and d) media-related competences. Among the major forces shaping the development of the media during the period under study, the economic recession that the country experienced between 2009 and 2018, and the spread of the internet, certainly stand out. Both these factors had a profound impact on media market structures and on journalism. The effects of digitalization are also evident in changing media use and supply practices. Overall, these forces create risks and opportunities for a media system whose development has been shaped by the close connection between the media and the political system

GREECE. Risks and Opportunities Related to Media and Journalism Studies (2000–2020). Case Study on the National Research and Monitoring Capabilities.

Research and data sources for the analysis of risks affecting, and opportunities for, deliberative communication in Greece reveal significant differences across the four Mediadelcom domains under study. Academic research is well advanced in the domain of law, but not particularly developed in the sphere of media ethics. Academic research in the domain of journalism is wellestablished and expanding, but data and statistics on journalism are scarce. In the domain of media usage, academic research is insufficiently institutionalized, while data collection is dispersed across commercial research bodies. The domain of media-related competences is the least developed of all in terms of the research and data available. The heterogeneity of the research and data sources available in the four domains reviewed undermines the potential for monitoring and assessing risks and opportunities for deliberative communication

News media representations of a common EU foreign and security policy: a cross-national content analysis of CFSP coverage in national quality newspapers

This study is a cross-national comparative content analysis of the broadsheet press coverage of EU Common Foreign and Security issues (n=1453) focusing on the presence of indicators of a European Public Sphere. Specifically, we investigated the visibility of Common Foreign and Security Policy (CFSP) stories, featuring actors, the tone of coverage and the presence of ‘risk’ and ‘opportunity’ frames. We found that CFSP was more visible in broadsheets during key events. In terms of actors in the news, coverage was primarily Europeanized. When evaluative, CFSP news had a distinctive, positive dimension, especially with reference to the European Union (EU) as an entity. CFSP issues were more frequently framed in terms of ‘opportunity’ rather than in terms of ‘risk’. Our findings suggest that the news coverage of CFSP is truly different from the coverage of EU affairs in general. Implications for the formation of public opinion and the legitimacy of CFSP are discussed