65,145 research outputs found
Cross polarization of nano-objects located on a flat substrate in the presence of a glass microparticle
No full textIn this work, we theoretically show that the deep subwavelength objects located on a dielectric substrate under a glass microcylinder sufficiently close to its bottom point are strongly polarized in the direction that is radial with respect to the microcylinder. This is even in the case when the structure is illuminated by the normally incident light. Though the incident electric field in the area of the objects is polarized almost tangentially to the cylinder surface, a significant cross polarization arises in the object due to its near-field coupling with the cylinder. In accordance with our previous works, the radial polarization is the key prerequisite of the super-resolution granted by a glass microsphere. Extending our results to the 3D case, we claim that the same cross-polarization effect should hold for a glass microsphere. In other words, the reported study shows that the parasitic spread image created by the tangential polarization of the objects should not mask the subwavelength image created by the radial polarization.Peer reviewe
Inverse propagation method for evaluation of super-resolution granted by dielectric microparticles
No full textPublisher Copyright: © 2022 Optica Publishing GroupIn this work we report a theoretical study of the lateral resolution granted by a simple glass microcylinder. In this 2D study, we had in mind the 3D analogue—a microsphere whose ability to form a deeply subwavelength and strongly magnified image of submicrometer objects has been known since 2011. Conventionally, the microscope in which such an image is observed is tuned to see the areas behind the microsphere. This corresponds to the location of the virtual source formed by the microsphere at a distance longer than the distance of the real source to the miscroscope. Recently, we theoretically found a new scenario of super-resolution, when the virtual source is formed in the wave beam transmitted through the microsphere. However, in this work we concentrated on the case when the super-resolution is achieved in the impractical imaging system, in which the microscope objective lens is replaced by a microlens located at a distance smaller than the Rayleigh range. The present paper theoretically answers an important question: Which scenario of far-field nanoimaging by a microsphere grants the finest spatial resolution at very large distances? We found that the novel scenario (corresponding to higher refractive indices) promises further enhancement of the resolution.Peer reviewe
Simovski, “Dynamic model of artificial reactive impedance surfaces
No full textAbstract|New arti cial reactive impedance surfaces have been recently suggested by Sievenpiper et al. for antenna and waveguide applications. In particular, high impedance values corresponding to a magnetic wall can be realized in dense arrays of conducting patches over a conducting plane. In this paper, a dynamic model for the electromagnetic properties of such structures is developed. The analytical model takes into account electromagnetic interactions between all patches in in nite arrays excited by normally incident plane waves, as well as higher-order Floquet modes between the array and the ground plane. The results are compared with the known experiments
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Accuracy of homogenization models for finite high-impedance surfaces located in the proximity of a horizontal dipole
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Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Revisiting substrate-induced bianisotropy in metasurfaces
No full textRecently, it has been shown that a metasurface of plasmonic nanospheres deposited on a highly refractive substrate requires a bianisotropic magnetoelectric coupling for its effective description. The effect has been coined substrate-induced bianisotropy. It leads to an asymmetric reflectance similar to bianisotropic metasurfaces. In this work, through a circuit model, we show that such bianisotropy does not necessarily emerge for all substrated metasurfaces. Indeed, we show that the thickness of the metasurface plays a crucial role to encounter substrate-induced bianisotropy. Moreover, by taking advantage of substrate-induced bianisotropy, we present the necessary conditions for the circuit model parameters to compensate the asymmetric reflectance generated by an intrinsically bianisotropic metasurface. We finally express that, in substrated metasurfaces, the asymmetric reflectance and the bianisotropic response are two separate issues albeit with interdependencies.Peer reviewe
Molecular structure of highly excited resonant states in Mg-24 and the corresponding Be-8+O-16 and C-12+C-12 decays
No full textExotic Be-8 and C-12 decays from high-lying resonances in Mg-24 are analyzed in terms of a cluster model. The calculated quantities agree well with the corresponding experimental data. It is found that the calculated decay widths are very sensitive to the angular momentum carried by the outgoing cluster. It is shown that this property makes cluster decay a powerful tool to determine the spin as well as the molecular structures of the resonances.Physics, NuclearSCI(E)7ARTICLE5null8
Letter from J. R. Eakin to Arthur G. Ringland
No full textLetter (copy) from J. R. Eakin to Arthur C. Ringland about the alignment of 40 acres near the Buggeln ranch
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