5,778 research outputs found

    Size-dependent nonlocal effects in plasmonic semiconductor particles

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    Localized surface plasmons (LSP) in semiconductor particles are expected to exhibit spatial nonlocal response effects as the geometry enters the nanometer scale. To investigate these nonlocal effects, we apply the hydrodynamic model to nanospheres of two different semiconductor materials: intrinsic InSb and nn-doped GaAs. Our results show that the semiconductors indeed display nonlocal effects, and that these effects are even more pronounced than in metals. In a 150 nm150\mathrm{\,nm} InSb particle at 300 K300\mathrm{\,K}, the LSP frequency is blueshifted 35%, which is orders of magnitude larger than the blueshift in a metal particle of the same size. This property, together with their tunability, makes semiconductors a promising platform for experiments in nonlocal effects.Comment: 7 pages, 3 figures, 1 table, corrected typos in text and figure

    Mode-Field Radius of Photonic Crystal Fibers Expressed by the V-parameter

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    We numerically calculate the equivalent mode-field radius of the fundamental mode in a photonic crystal fiber (PCF) and show that this is a function of the V-parameter only and not the relative hole size. This dependency is similar to what is found for graded-index standard fibers and we furthermore show that the relation for the PCF can be excellently approximated with the same general mathematical expression. This is to our knowledge the first semi-analytical description of the mode-field radius of a PCF.Comment: Accepted for Opt. Let

    Testing Milk and Cream

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    The Babcock test and the scales are in reality the foundation of profitable dairy farming. By the proper use of these utensils it is possible, not only to find the average production of the cows in general, but also to single out those which are not paying for their keep. By disposing of those animals and replacing them with better ones, it is possible to put dairy farming on a business-like and profitable basis

    Improved large-mode area endlessly single-mode photonic crystal fibers

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    We numerically study the possibilities for improved large-mode area endlessly single mode photonic crystal fibers for use in high-power delivery applications. By carefully choosing the optimal hole diameter we find that a triangular core formed by three missing neighboring air holes considerably improves the mode area and loss properties compared to the case with a core formed by one missing air hole. In a realized fiber we demonstrate an enhancement of the mode area by ~30 % without a corresponding increase in the attenuation.Comment: 3 pages including 3 eps-figures. Accepted for Optics Letter

    Low-loss photonic crystal fibers for transmission systems and their dispersion properties

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    We report on a single-mode photonic crystal fiber with attenuation and effective area at 1550 nm of 0.48 dB/km and 130 square-micron, respectively. This is, to our knowledge, the lowest loss reported for a PCF not made from VAD prepared silica and at the same time the largest effective area for a low-loss (< 1 dB/km) PCF. We briefly discuss the future applications of PCFs for data transmission and show for the first time, both numerically and experimentally, how the group velocity dispersion is related to the mode field diameterComment: 5 pages including 3 figures + 1 table. Accepted for Opt. Expres

    Photonic crystal fiber with a hybrid honeycomb cladding

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    We consider an air-silica honeycomb lattice and demonstrate a new approach to the formation of a core defect. Typically, a high or low-index core is formed by adding a high-index region or an additional air-hole (or other low-index material) to the lattice, but here we discuss how a core defect can be formed by manipulating the cladding region rather than the core region itself. Germanium-doping of the honeycomb lattice has recently been suggested for the formation of a photonic band-gap guiding silica-core and here we experimentally demonstrate how an index-guiding silica-core can be formed by fluorine-doping of the honeycomb lattice.Comment: 5 pages including 3 figures. Accepted for Optics Expres

    Modal cut-off and the V-parameter in photonic crystal fibers

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    We address the long-standing unresolved problem concerning the V-parameter in a photonic crystal fiber (PCF). Formulate the parameter appropriate for a core-defect in a periodic structure we argue that the multi-mode cut-off occurs at a wavelength lambda* which satisfies V_PCF(lambda*)=pi. Comparing to numerics and recent cut-off calculations we confirm this result.Comment: 3 pages including 2 figures. Accepted for Optics Letter

    Predicting macrobending loss for large-mode area photonic crystal fibers

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    We report on an easy-to-evaluate expression for the prediction of the bend-loss for a large mode area photonic crystal fiber (PCF) with a triangular air-hole lattice. The expression is based on a recently proposed formulation of the V-parameter for a PCF and contains no free parameters. The validity of the expression is verified experimentally for varying fiber parameters as well as bend radius. The typical deviation between the position of the measured and the predicted bend loss edge is within measurement uncertainty.Comment: Accepted for Optics Expres

    Soft Cheese Making

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    Cheese eating would be greatly Increased In the United States If the value of this food were generally understood. Pound for pound cottage cheese, for example, contains more protein, or tissue building material, than the various meats; It contains from one-third to three-fourths as much of the energy supplying materials as meat. The value of cheese has long been recognized In Europe. While In 1913 the people of the United States ate only 3.45 lbs. of cheese per person, the people of England ate 5.19 lbs. per person. In Holland, 8.07 lbs. per person was eaten In 1911. It\u27s use would undoubtedly Increase if the economy of cheese were more generally known for some of the soft cheeses appeal especially to American taste
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