Author
John B. Pendry
Other affiliations: University of California, San Diego, Duke University, Bell Labs ...read more
Bio: John B. Pendry is an academic researcher from Imperial College London. The author has contributed to research in topics: Metamaterial & Plasmon. The author has an hindex of 100, co-authored 536 publications receiving 88802 citations. Previous affiliations of John B. Pendry include University of California, San Diego & Duke University.
Papers published on a yearly basis
Papers
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TL;DR: In this article, the authors present the first experimental realisation of a non-resonant metamaterial designed to operate at zero frequency, based on a recently proposed template for an anisotropic magnetic metammaterial consisting of an array of superconducting plates.
Abstract: Electromagnetic metamaterials are a class of materials which have been artificially structured on a subwavelength scale. They are currently the focus of a great deal of interest because they allow access to previously unrealisable properties like a negative refractive index. Most metamaterial designs have so far been based on resonant elements, like split rings, and research has concentrated on microwave frequencies and above. In this work, we present the first experimental realisation of a non-resonant metamaterial designed to operate at zero frequency. Our samples are based on a recently-proposed template for an anisotropic magnetic metamaterial consisting of an array of superconducting plates. Magnetometry experiments show a strong, adjustable diamagnetic response when a field is applied perpendicular to the plates. We have calculated the corresponding effective permeability, which agrees well with theoretical predictions. Applications for this metamaterial may include non-intrusive screening of weak DC magnetic fields.
100 citations
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TL;DR: It is shown how luminal metamaterials generalize the parametric oscillator concept, realize giant broadband nonreciprocity, achieve efficient one-way amplification, pulse compression, and harmonic generation, and propose a realistic implementation in double-layer graphene.
Abstract: Time has emerged as a new degree of freedom for metamaterials, promising new pathways in wave control. However, electromagnetism suffers from limitations in the modulation speed of material parameters. Here we argue that these limitations can be circumvented by introducing a traveling-wave modulation, with the same phase velocity of the waves. We show how luminal metamaterials generalize the parametric oscillator concept, realize giant broadband nonreciprocity, achieve efficient one-way amplification, pulse compression, and harmonic generation, and propose a realistic implementation in double-layer graphene.
99 citations
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TL;DR: In this paper, a simple scheme for calculating Green's functions for photons propagating in complex structured dielectrics or other photonic systems is proposed based on an extension of the finite-difference time-domain (FDTD) method, originally proposed by Yee [IEEE Trans Antennas Propag 14, 302 (1966)], also known as the order-$N$ method.
Abstract: In this paper we shall propose a simple scheme for calculating Green's functions for photons propagating in complex structured dielectrics or other photonic systems The method is based on an extension of the finite-difference time-domain (FDTD) method, originally proposed by Yee [IEEE Trans Antennas Propag 14, 302 (1966)], also known as the order-$N$ method [Chan, Yu, and Ho, Phys Rev 51, 16 635 (1995)] which has recently become a popular way of calculating photonic band structures We give a transparent derivation of the order-$N$ method which, in turn, enables us to give a simple yet rigorous derivation of the criterion for numerical stability as well as statements of charge and energy conservation which are exact even on the discrete lattice We implement this using a general, nonorthogonal coordinate system without incurring the computational overheads normally associated with nonorthogonal FDTD We present results for local densities of states calculated using this method for a number of systems First, we consider a simple one-dimensional dielectric multilayer, identifying the suppression in the state density caused by the photonic band gap and then observing the effect of introducing a defect layer into the periodic structure Second, we tackle a more realistic example by treating a defect in a crystal of dielectric spheres on a diamond lattice This could have application to the design of superefficient laser devices utilizing defects in photonic crystals as laser cavities
98 citations
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98 citations
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TL;DR: In this paper, the spin polarised electron sources were used to study magnetism with the inverse photoemission (IPE) technique, with a probability related by time reversal to the excitation of an electron in angle resolved photo-emission.
Abstract: Electrons in the range 0-20 eV accelerated by the potential inside a surface emit photons over a range of frequencies, with a probability related by time reversal to the excitation of an electron in angle resolved photoemission. Theory indicates that the yield is high enough to make the experiments much simpler than photoemission, providing a more valuable probe of unoccupied electron states than any available so far. Particularly interesting is the possibility of using the new spin polarised electron sources to study magnetism with the inverse photoemission (IPE) technique.
97 citations
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28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组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�ly.
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。
18,940 citations
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TL;DR: By altering the structure of a metal's surface, the properties of surface plasmons—in particular their interaction with light—can be tailored, which could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved.
Abstract: Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons--in particular their interaction with light--can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.
10,689 citations
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TL;DR: These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root ofɛ·μ for the frequencies where both the permittivity and the permeability are negative.
Abstract: We present experimental scattering data at microwave frequencies on a structured metamaterial that exhibits a frequency band where the effective index of refraction (n) is negative. The material consists of a two-dimensional array of repeated unit cells of copper strips and split ring resonators on interlocking strips of standard circuit board material. By measuring the scattering angle of the transmitted beam through a prism fabricated from this material, we determine the effective n, appropriate to Snell's law. These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root of epsilon.mu for the frequencies where both the permittivity (epsilon) and the permeability (mu) are negative. Configurations of geometrical optical designs are now possible that could not be realized by positive index materials.
8,477 citations
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TL;DR: In this paper, it was shown that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu/sub eff/, which can be tuned to values not accessible in naturally occurring materials.
Abstract: We show that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu//sub eff/, which can be tuned to values not accessible in naturally occurring materials, including large imaginary components of /spl mu//sub eff/. The microstructure is on a scale much less than the wavelength of radiation, is not resolved by incident microwaves, and uses a very low density of metal so that structures can be extremely lightweight. Most of the structures are resonant due to internal capacitance and inductance, and resonant enhancement combined with compression of electrical energy into a very small volume greatly enhances the energy density at critical locations in the structure, easily by factors of a million and possibly by much more. Weakly nonlinear materials placed at these critical locations will show greatly enhanced effects raising the possibility of manufacturing active structures whose properties can be switched at will between many states.
8,135 citations
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TL;DR: Recent advances at the intersection of plasmonics and photovoltaics are surveyed and an outlook on the future of solar cells based on these principles is offered.
Abstract: The emerging field of plasmonics has yielded methods for guiding and localizing light at the nanoscale, well below the scale of the wavelength of light in free space. Now plasmonics researchers are turning their attention to photovoltaics, where design approaches based on plasmonics can be used to improve absorption in photovoltaic devices, permitting a considerable reduction in the physical thickness of solar photovoltaic absorber layers, and yielding new options for solar-cell design. In this review, we survey recent advances at the intersection of plasmonics and photovoltaics and offer an outlook on the future of solar cells based on these principles.
8,028 citations