Yuri S. Kivshar

Bio: Yuri S. Kivshar is an academic researcher from Australian National University. The author has contributed to research in topics: Metamaterial & Soliton. The author has an hindex of 126, co-authored 1845 publications receiving 79415 citations. Previous affiliations of Yuri S. Kivshar include Technische Universität Darmstadt & Los Alamos National Laboratory.

Optimal tapers for compensating losses in plasmonic waveguides

Abstract: We consider propagation of surface plasmon polaritons in two-dimensional tapered slot waveguides. We derive an analytical formula for the change of the amplitude of a plasmon mode due to tapering. We show that the taper leads to the field enhancement effectively compensating the mode attenuation due to losses. We obtain numerically the shape of the optimal function of the taper that provides exact loss compensation. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Inverted Yablonovite Fabricated by the Direct Laser Writing Method and Its Photonic Structure

Abstract: Threedimensional photonic crystals with an inverted yablonovite structure have been fabricated by the direct laser writing method based on the twophoton polyme rization of a photosensitive material. The correspon� dence of the structure of the samples to the inverted yablonovite lattice has been confirmed by scanning elec� tron microscopy. The photonic band structure of inverted yablonovite, as well as a number of related photonic materials with an fcc lattice, has been calculated. It has been found that the photonic properties of opal and yablonovite are opposite: the complete photonic band gap appears in inverted opal and direct yablonovite and is absent in direct opal and inverted yablonovite. A method for the fabrication of ideal threedimensional pho� tonic structures having the complete photonic band gap in the infrared and visible spectral ranges has been discussed. DOI: 10.1134/S0021364012090123

Band-gap properties of two-dimensional low-index photonic crystals

Abstract: We study the band-gap properties of two-dimensional photonic crystals created by a lattice of rods or holes conformed in a symmetric or asymmetric triangular structure. Using numerical plane-wave method, we calculate a minimum value of the refractive-index contrast for opening both partial and full two-dimensional spectral gaps for both TM- and TE-polarized waves. We also analyze the effect of ellipticity of rods and holes and their orientation on the threshold value and the relative size of the band gaps.

Metamaterials with tunable nonlinearity

Abstract: A new approach to the implementation of electromagnetic metamaterials with tunable nonlinearity in the microwave range has been proposed. The characteristics of a split ring resonator equipped with a varactor diode to ensure a nonlinear response and a photodiode to supply a dc bias voltage depending on the illumination intensity have been examined. It has been shown that an increase in the illumination intensity shifts the resonance response toward lower frequency and an increase in the power of the exciting signal shifts the resonance response toward higher frequency.

Self-trapping of polychromatic light in nonlinear periodic photonic structures

Abstract: We study dynamical reshaping of polychromatic beams due to collective nonlinear self-action of multiple-frequency components in periodic and semi-infinite photonic lattices and predict the formation of polychromatic gap solitons and polychromatic surface solitons due to light localization in spectral gaps. We show that the self-trapping efficiency and structure of emerging polychromatic solitons depend on the input spectrum due to the lattice-enhanced dispersion, including the effect of crossover from localization to diffraction in media with defocusing nonlinearity.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。