Asymmetric comb waveguide for strong interactions between atoms and light.

Coupling quantum emitters and nanostructures, in particular cold atoms and optical waveguides, has recently raised a large interest due to unprecedented possibilities of engineering light-matter interactions. In this work, we propose a new type of periodic dielectric waveguide that provides strong interactions between atoms and guided photons with an unusual dispersion. We design an asymmetric comb waveguide that supports a slow mode with a quartic (instead of quadratic) dispersion and an electric field that extends far into the air cladding for an optimal interaction with atoms. We compute the optical trapping potential formed with two guided modes at frequencies detuned from the atomic transition. We show that cold Rubidium atoms can be trapped as close as 100 nm from the structure in a 1.3-mK-deep potential well. For atoms trapped at this position, the emission into guided photons is largely favored, with a beta factor as high as 0.88 and a radiative decay rate into the slow mode 10 times larger than the free-space decay rate. These figures of merit are obtained at a moderately low group velocity of c/50.

Mutual Information between Reflected and Transmitted Speckle Images.

We study theoretically the mutual information between reflected and transmitted speckle patterns produced by wave scattering from disordered media. The mutual information between the two speckle images recorded on an array of N detection points (pixels) takes the form of long-range intensity correlation loops that we evaluate explicitly as a function of the disorder strength and the Thouless number g. Our analysis, supported by extensive numerical simulations, reveals a competing effect of cross-sample and surface spatial correlations. An optimal distance between pixels is proven to exist that enhances the mutual information by a factor Ng compared to the single-pixel scenario.

[Infection control in interventional radiology: good practice guideline]. / Hygiène en radiologie interventionnelle: présentation d'un guide de bonnes pratiques.

PURPOSE: In 1997, two studies were performed in interventional radiology units, one of them by the CCLIN Paris-Nord and the other, by the staff of the vascular radiology department of Hautepierre Hospital of Strasbourg in collaboration with the CCLIN Est. The results have shown poor compliance with recommended infection control guidelines and standard precautions. A working group was set up by the CCLIN Paris-Nord, with radiologists, radiology technicians, nurses and infection control practitioners to elaborate guidelines for infection control practices in interventional radiology. Materials and methods. These guidelines were compiled using legislation, consensus or expert conferences, evaluations or studies which had demonstrated a benefit to prevent infectious risk. The working group also formulated its own recommendations when no pre-existing document was available. These recommendations have been categorized according to evidence of benefit in infectious risk prevention. RESULTS: Guidelines are divided in two parts. The first part describes rooms and optimal architecture of the interventional radiology unit, flows (patients, staff, material, linen and waste), type of floor and furniture surfaces, and environment of the interventional unit (air, water, room and device cleaning). The second part details staff garments, hand washing procedures according to tasks, and protection against accident for the staff (accidental blood exposure, antimitotic drugs). Recommendations have been elaborated for patients'skin preparation and equipment handling (contrast product, automatic injector, US, scanner). A proposal for work organization is made regarding nursing protocols, documents of maintenance, surveillance of medical devices.