123 research outputs found
Plasmonic crystal demultiplexer and multiports
Artificially built periodic optical structures in dielectric and metallic
media have generated considerable interest due to their potential for optical
device miniaturization. In this context plasmonics, i.e., optics based on
surface plasmon polaritons (SPPs) offers new exciting prospects. SPPs are
hybrid light/electron surface waves at the interface between a dielectric and a
metal and as such hold the potential for 2D optical functionality. Indeed, SPP
elements as mirrors, splitters and interferometers have been recently
demonstrated. However, for plasmonics to qualify at the information technology
level requires necessarily the realization of wavelength division
(demultiplexing) which constitutes a fundamental ingredient of optical
communication. In the following we experimentally demonstrate 2D SPP
demultiplexing in the visible spectral range by using photonic crystals for
SPPs (plasmonic crystals). In addition, we demonstrate that plasmonic crystal
are capable of realizing integrated linear multiports which could constitute
building blocks of analog or quantum optical computing.Comment: Nano Lett.7, 1697 (2007
How to erase surface plasmon fringes
We report the realization of a dual surface plasmon polariton (SPP)
microscope based on leakage radiation (LR) analysis. The microscope can either
image SPP propagation in the direct space or tin the Fourier space. This
particularity allows in turn manipulation of the LR image for a clear
separation of different interfering SPP contributions present close to optical
nanoelements.Comment: Appl. Phys. Lett. 89, 091117 (2006
High performance p-type organic thin film transistors with an intrinsically photopatternable, ultrathin polymer dielectric layer
AbstractA high-performing bottom-gate top-contact pentacene-based oTFT technology with an ultrathin (25–48nm) and electrically dense photopatternable polymeric gate dielectric layer is reported. The photosensitive polymer poly((±)endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid, diphenylester) (PNDPE) is patterned directly by UV-exposure (λ=254nm) at a dose typical for conventionally used negative photoresists without the need for any additional photoinitiator. The polymer itself undergoes a photo-Fries rearrangement reaction under UV illumination, which is accompanied by a selective cross-linking of the macromolecules, leading to a change in solubility in organic solvents. This crosslinking reaction and the negative photoresist behavior are investigated by means of sol–gel analysis. The resulting transistors show a field-effect mobility up to 0.8cm2V−1s−1 at an operation voltage as low as −4.5V. The ultra-low subthreshold swing in the order of 0.1Vdec−1 as well as the completely hysteresis-free transistor characteristics are indicating a very low interface trap density. It can be shown that the device performance is completely stable upon UV-irradiation and development according to a very robust chemical rearrangement. The excellent interface properties, the high stability and the small thickness make the PNDPE gate dielectric a promising candidate for fast organic electronic circuits
Surface Plasmon Polariton microscope with Parabolic Reflectors
We report the realization of a two--dimensional optical microscope for
surface plasmons polaritons (SPPs) based on parabolic Bragg mirrors. These
mirrors are built from lithographically fabricated gold nanostructures on gold
thin films. We show by direct imaging by leakage radiation microscopy that the
magnification power of the SPP microscope follows basic predictions of
geometrical optics. Spatial resolution down to the value set by the diffraction
limit is demonstrated.Comment: Opt.Lett.32, 2414 (2007
Molecular adsorbent recirculating system and hemostasis in patients at high risk of bleeding: an observational study
INTRODUCTION: Liver failure is associated with reduced synthesis of clotting factors, consumptive coagulopathy, and platelet dysfunction. The aim of the study was to evaluate the effects of liver support using a molecular adsorbent recirculating system (MARS) on the coagulation system in patients at high risk of bleeding. METHODS: We studied 61 MARS treatments in 33 patients with acute liver failure (n = 15), acute-on-chronic liver failure (n = 8), sepsis (n = 5), liver graft dysfunction (n = 3), and cholestasis (n = 2). Standard coagulation tests, standard thromboelastography (TEG), and heparinase-modified and abciximab-fab-modified TEG were performed immediately before and 30 minutes after commencement of MARS, and after the end of MARS treatment. Prostaglandin I(2 )was administered extracorporeally to all patients; 17 patients additionally received unfractioned heparin. RESULTS: Three moderate bleeding complications in three patients, requiring three to four units of packed red blood cells, were observed. All were sufficiently managed without interrupting MARS treatment. Although there was a significant decrease in platelet counts (median, 9 G/l; range, -40 to 145 G/l) and fibrinogen concentration (median, 15 mg/dl; range, -119 to 185 mg/dl) with a consecutive increase in thrombin time, the platelet function, as assessed by abciximab-fab-modified TEG, remained stable. MARS did not enhance fibrinolysis. CONCLUSION: MARS treatment appears to be well tolerated during marked coagulopathy due to liver failure. Although MARS leads to a further decrease in platelet count and fibrinogen concentration, platelet function, measured as the contribution of the platelets to the clot firmness in TEG, remains stable. According to TEG-based results, MARS does not enhance fibrinolysis
Momentum transfer for momentum transfer-free which-path experiments
We analyze the origin of interference disappearance in which-path double
aperture experiments. We show that we can unambiguously define an observable
momentum transfer between the quantum particle and the path detector and we
prove in particular that the so called ``momentum transfer free'' experiments
can be in fact logically interpreted in term of momentum transfer.Comment: to appear in Phys. Rev . A (2006). (7 pages, 2 figures
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