We demonstrate that plasmonic helical gratings consisting of metallic nanowires imprinted with helical grooves or ridges can be used efficiently to generate plasmonic vortices with radius much smaller than the operating wavelength. In our proposed approach, these helical surface gratings are designed so that plasmon modes with different azimuthal quantum numbers (topological charge) are phase-m...

Biased Brownian motion of point-size particles in a three-dimensional tube with varying cross-section is investigated. In the fashion of our recent work, Martens et al. [Phys. Rev. E 83, 051135 (2011)] we employ an asymptotic analysis to the stationary probability density in a geometric parameter of the tube geometry. We demonstrate that the leading order term is equivalent to the Fick-Jacobs a...

introduction : hospital infections are one of the important reasons of mortality and incurred expenses. therefore, we must control these infections by identifying contamination sources. the aim of this study was the determination of bacterial pollution of corrugated anesthesia sets in surgical rooms. methods: this study was an analytic-description one performed in training hospitals of yazd cit...