Single-photon generation and simultaneous observation of wave and particle properties

We describe an experiment that generates single photons on demand and measures properties accounted to both particle- and wave-like features of light. The measurement is performed by exploiting data that are sampled simultaneously in a single experimental run.Comment: The following article has been submitted to Proceedings of "Foundations of probability and physics-3", Vaxjo, Sweden 2004. After it is published, it will be found at http://proceedings.aip.org/ . 1 Reference was added in version

'Flying Plasmons': Fabry-P\`erot Resonances in Levitated Silver Nanowires

Plasmonic nano structures such as wire waveguides or antennas are key building blocks for novel highly integrated photonics. A quantitative understanding of the optical material properties of individual structures on the nanoscale is thus indispensable for predicting and designing the functionality of complex composite elements. In this letter we study propagating surface plasmon polaritons in single silver nanowires isolated from its environment by levitation in a linear Paul trap. Symmetry-breaking effects, e.g., from supporting substrates are completely eliminated in this way. Illuminated with white light from a supercontinuum source, Fabry-P\`erot-like resonances are observed in the scattering spectra obtained from the ends of the nanowires. The plasmonic nature of the signal is verified by local excitation and photon collection corresponding to a clean transmission measurement through a Fabry-P\`erot resonator. A numerical simulation is used to compute the complex effective refractive indices of the nanowires as input parameter for a simple Fabry-P\`erot model, which nicely reproduces the measured spectra despite the highly dispersive nature of the system. Our studies pave the way for quantitative characterization of nearly any trappable plasmonic nano object, even of fragile ones such as droplets of liquids or molten metal and of nearly any nanoresonator based on a finite waveguide with implications for modeling of complex hybrid structures featuring strong coupling or lasing. Moreover, the configuration has the potential to be complemented by gas sensors to study the impact of hot electrons on catalytic reactions nearby plasmonic particles

Governing Integrated Water Resources Management: Mutual Learning and Policy Transfer

Integrated Water Resources Management (IWRM) has become a global paradigm for the governance of surface, coastal and groundwaters. This Special Issue contains twelve articles related to the transfer of IWRM policy principles. The articles explore three dimensions of transfer—causes, processes, outcomes—and offer a theoretically inspiring, methodologically rich and geographically diverse engagement with IWRM policy transfer around the globe. As such, they can also productively inform a future research agenda on the ‘dimensional’ aspects of IWRM governance. Regarding the causes, the contributions apply, criticise, extend or revise existing approaches to policy transfer in a water governance context, asking why countries adopt IWRM principles and what mechanisms are in place to understand the adoption of these principles in regional or national contexts. When it comes to processes, articles in this Special Issue unpack the process of policy transfer and implementation and explore how IWRM principles travel across borders, levels and scales. Finally, this set of papers looks into the outcomes of IWRM policy transfer and asks what impact IWRM principles, once implemented, gave on domestic water governance, water quality and water supply, and how effective IWRM is at addressing critical water issues in specific countries