8,522 research outputs found
Resonant transmission of light through finite chains of subwavelength holes
In this paper we show that the extraordinary optical transmission phenomenon
found before in 2D hole arrays is already present in a linear chain of
subwavelength holes, which can be considered as the basic geometrical unit
showing this property. In order to study this problem we have developed a new
theoretical framework, able to analyze the optical properties of finite
collections of subwavelength apertures and/or dimples (of any shape and placed
in arbitrary positions) drilled in a metallic film.Comment: Accepted for publication in Phys. Rev. Let
Observation of enhanced transmission for s-polarized light through a subwavelength slit
Enhanced optical transmission (EOT) through subwavelength apertures is
usually obtained for p-polarized light. The present study experimentally
investigates EOT for s-polarized light. A subwavelength slit surrounded on each
side by periodic grooves has been fabricated in a gold film and covered by a
thin dielectric layer. The excitation of s-polarized dielectric waveguide modes
inside the dielectric film strongly increases the s-polarized transmission.
Transmission measurements are compared with a coupled mode model and show good
qualitative agreement. Adding a waveguide can improve light transmission
through subwavelength apertures, as both s and p-polarization can be
efficiently transmitted.Comment: 11 pages, 3 figures, submitted to Applied Physics Letter
Combinatorial properties and characterization of glued semigroups
This work focuses on the combinatorial properties of glued semigroups and
provides its combinatorial characterization. Some classical results for affine
glued semigroups are generalized and some methods to obtain glued semigroups
are developed.Comment: 13 pages, 6 figures, This paper was initially presented at the
"Centennial Congress RSME2011" http://campus.usal.es/~rsme2011
Influence of the Yesa reservoir on floods of the AragĂłn River, central Spanish Pyrenees
International audienceThe Yesa reservoir, the largest Pyrenean reservoir, was constructed in 1959 to supply water to new irrigated areas in the Ebro Depression, NE Spain. It is filled from October to May-June and then releases large quantities of water in the summer via the Bardenas Canal. The results confirm that the frequency of floods downstream of the dam decreased. The reduction mainly depends on two factors: i) the water storage level, and ii) the season of the year. Floods are very well controlled when the reservoir level is lower than 50%. Between 50 and 70%, only the highest floods are controlled. Finally, the reservoir retains mainly autumn and spring floods; most winter floods are released downstream to ensure the safety of the dam. Keywords: reservoir, flood control, flood seasonality, flood frequency, river regime, Pyrenees</p
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