Showing papers by "John B. Pendry published in 2003"
TL;DR: In this article, the sensitivity of this subwavelength focus to the slab material properties and periodicity was studied, and the connection to slab surface plasmon modes was made.
Abstract: A planar slab of material, for which both the permittivity and permeability have the values of −1, can bring not only the propagating fields associated with a source to a focus, but can also refocus the nonpropagating near fields, thereby achieving resolution beyond the diffraction limit. We study the sensitivity of this subwavelength focus to the slab material properties and periodicity, and note the connection to slab surface plasmon modes. We conclude that significant subwavelength resolution is achievable with a single negative index slab, but only over a restrictive range of parameters.
485 citations
TL;DR: In this paper, the authors investigate the transmission of evanescent waves through a slab of photonic crystal and explore the recently suggested possibility of focusing light with subwavelength resolution, and they find that the periodicity of the photonic lattice imposes an upper cutoff to the transverse wave vector of evanecent waves that can be amplified, and thus a photonic-crystal superlens is free of divergences even in the lossless case.
Abstract: We investigate the transmission of evanescent waves through a slab of photonic crystal and explore the recently suggested possibility of focusing light with subwavelength resolution. The amplification of near-field waves is shown to rely on resonant coupling mechanisms to surface photon bound states, and the negative refractive index is only one way of realizing this effect. It is found that the periodicity of the photonic crystal imposes an upper cutoff to the transverse wave vector of evanescent waves that can be amplified, and thus a photonic-crystal superlens is free of divergences even in the lossless case. A detailed numerical study of the optical image of such a superlens in two dimensions reveals a subtle and very important interplay between propagating waves and evanescent waves on the final image formation. Particular features that arise due to the presence of near-field light are discussed.
427 citations
TL;DR: In this paper, the authors considered refinements of the original prescription designed to overcome the limitations of imperfect materials and showed that a multilayer stack of positive and negative refractive index media is less sensitive to imperfections.
Abstract: In an earlier paper we introduced the concept of the perfect lens which focuses both near and far electromagnetic fields, hence attaining perfect resolution. Here we consider refinements of the original prescription designed to overcome the limitations of imperfect materials. In particular we show that a multilayer stack of positive- and negative-refractive-index media is less sensitive to imperfections. It has the novel property of behaving like a fibre-optic bundle but one that acts on the near field, and not just the radiative component. The effects of retardation are included and minimized by making the slabs thinner. Absorption then dominates image resolution in the near field. The deleterious effects of absorption in the metal are reduced for thinner layers.
307 citations
TL;DR: Pendry et al. as mentioned in this paper suggested a compensation for the losses by introducing optical gain media into the lens design, which showed a dramatic improvement in performance for a silver/gain composite medium at optical frequencies.
Abstract: A recent paper [J. B. Pendry, Phys. Rev. Lett. 85, 3966 (2000)] showed how to construct a superlens that focuses the near-field radiation and, hence, produce an image resolution unlimited by wavelength. The prescription requires lossless materials with a negative refractive index: finite loss cuts off the finer details of the image. In this paper we suggest a compensation for the losses by introducing optical gain media into the lens design. Calculations demonstrate a dramatic improvement in performance for a silver/gain composite medium at optical frequencies.
296 citations
TL;DR: In this article, the authors introduce coordinate transformation, mapping a known system into an equivalent system to extend the result to a much wider class of structures including cylinders, spheres and intersecting planes, and hence show how to produce magnified images.
Abstract: A slab of negatively refracting material, thickness d, can focus an image at a distance 2d from the object. The negative slab cancels an equal thickness of positive space. This result is a special case of a much wider class of focusing: any medium can be optically cancelled by an equal thickness of material constructed to be an inverted mirror image of the medium, with , μ reversed in sign. We introduce the powerful technique of coordinate transformation, mapping a known system into an equivalent system, to extend the result to a much wider class of structures including cylinders, spheres and intersecting planes, and hence show how to produce magnified images. All the images are 'perfect' in the sense that both the near and far fields are brought to a focus and hence reveal sub-wavelength details.
289 citations
TL;DR: Here it is shown how a hollow cylinder of material can be designed to magnify an image but otherwise with the same perfection as the original lens.
Abstract: A slab of negatively refracting material is known to focus light and if n=-1 the focussing will be perfect, producing an image which is an exact replica of the object. Magnifying the image requires a new design concept in which the surface of the negatively refracting lens is curved. Here we show how a hollow cylinder of material can be designed to magnify an image but otherwise with the same perfection as the original lens. Curvature requires that e and µ are now a function of position.
202 citations
TL;DR: In this paper, the authors introduce coordinate transformation, mapping a known system into an equivalent system to extend the result to a much wider class of structures including cylinders, spheres, and intersecting planes and hence show how to produce magnified images.
Abstract: A slab of negatively refracting material, thickness d, can focus an image at a distance 2d from the object. The negative slab cancels an equal thickness of positive space. This result is a special case of a much wider class of focussing: any medium can be optically cancelled by an equal thickness of material constructed to be an inverted mirror image of the medium, with, $\epsilon$ and $\mu$ reversed in sign. We introduce the powerful technique of coordinate transformation, mapping a known system into an equivalent system, to extend the result to a much wider class of structures including cylinders, spheres, and intersecting planes and hence show how to produce magnified images. All the images are perfect in the sense that both the near and far fields are brought to a focus and hence reveal sub wavelength details.
192 citations
TL;DR: It is shown that certain metallic photonic crystals can enable negative refraction and subwavelength imaging without relying on a negative effective index.
Abstract: It is shown that certain metallic photonic crystals can enable negative refraction and subwavelength imaging without relying on a negative effective index. These metallic structures are very simple in design and appear straightforward for fabrication. Their unusual electromagnetic response should provide an interesting comparison with the metallic left-handed materials.
128 citations
TL;DR: A highly anisotropic magnetic metamaterial consisting of an array of Swiss Roll structures, resonant near 21.3 MHz, that behaves as a near-field imaging device consisting of a bundle of magnetic wires.
Abstract: We report on the development and use of a highly anisotropic magnetic metamaterial for near-field imaging. The material consists of an array of Swiss Roll structures, resonant near 21.3 MHz, with a peak value of relative permeability ~35. At this peak, the material transfers an input magnetic field pattern to the output face without loss of intensity and with a spatial resolution equal to the roll diameter. It behaves as a near-field imaging device consisting of a bundle of magnetic wires.
120 citations
98 citations
TL;DR: In this paper, the authors propose a novel mapping onto an anisotropic system which behaves like an optical fiber bundle, but operating on the near field, which minimizes the restrictions by structuring the lens into a series of thin slices.
Abstract: Some time ago it was shown that a slab of material with e 1 =−1, μ 1 =−1 and suspended in vacuo has the ability to focus a perfect image: both the near-field and far-field components are delivered to the image plane with the correct amplitude and phase reproducing every detail in the original source [Phys. Rev. Lett. 85 (2000) 3966]. Real materials fall short of this ideal particularly with respect to losses which manifest themselves as imaginary components to e1 and μ1. In this talk we shall examine how to minimise the restrictions by structuring the lens into a series of thin slices. This results in a novel mapping onto an anisotropic system which behaves like an optical fibre bundle, but operating on the near field.
TL;DR: New work finally sets the seal of experimental confirmation on negative refraction, which has opened the door to new phenomena — and controversy.
Abstract: An artificially created material with negative refractive index has opened the door to new phenomena — and controversy. New work finally sets the seal of experimental confirmation on negative refraction.
TL;DR: A Comment on the Letter by P. M. Valanju and the authors of the Letter offer a Reply.
Abstract: A Comment on the Letter by P. M. Valanju, R. M. Walser, and A. P. Valanju, Phys. Rev. Lett. 88, 187401 (2002). The authors of the Letter offer a Reply.
TL;DR: In this paper, the authors explore the possibility of designing photonic crystals to act as magnetic metamaterials: structures that exhibit magnetic properties despite the nonmagnetic character of their constituents.
Abstract: In this work, we explore the possibility of designing photonic crystals to act as magnetic metamaterials: structures that exhibit magnetic properties despite the nonmagnetic character of their constituents. The building blocks of a magnetic material are microscopic magnetic dipoles, and to create a synthetic analog we employ point-defect modes in a photonic crystal. We begin by identifying a point defect mode in a three-dimensional crystal whose local field pattern resembles an oscillating magnetic moment. By analyzing the far-field pattern of the field radiated from the defect, we prove quantitatively that such modes can be designed with a primarily magnetic character: over 98% of the emitted power goes into magnetic multipole radiation. Unlike the constituents of natural para- and ferromagnetic materials, these synthetic magnetic emitters can be designed to operate without losses even at optical frequencies.
TL;DR: It is shown that careful consideration of absorption results in solutions that are always well behaved and evolve smoothly and continuously to perfect resolution in the limiting case of zero absorption.
Abstract: In a recent Physical Review Letter [1] Garcia and Nieto Vesperinas (GNV) dispute the claim of perfect lensing made in [2]. The thrust of the GVN paper is that the solutions proposed in [2] imply infinite energy density and are therefore inadmissible. They claim that finite absorption leads to catastrophic collapse of the amplifying solutions vital to focussing and that no useful effect can be achieved. In this Comment I show that, on the contrary, careful consideration of absorption results in solutions that are always well behaved and evolve smoothly and continuously to perfect resolution in the limiting case of zero absorption.
Patent•
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TL;DR: In this article, a method for making an antenna and the antenna itself is described, where the antenna comprises a first region having a first refractive index and a second region having an additional negative one, such that radiation outside the second region is reproduced in the first region.
Abstract: A method for making an antenna and the antenna itself are described. The antenna comprises a first region having a first refractive index and a second region having a negative refractive index, the second region substantially surrounding the first region, such that radiation outside the second region is reproduced in the first region.
Journal Article•
TL;DR: A Comment on the Letter by P. M. Valanju as mentioned in this paper, Phys. Rev. Lett. 88, 187401 (2002) and a Reply to the authors of the Letter offer a Reply.
Abstract: A Comment on the Letter by P. M. Valanju, R. M. Walser, and A. P. Valanju, Phys. Rev. Lett. 88, 187401 (2002). The authors of the Letter offer a Reply.
Patent•
[...]
TL;DR: In this article, a method for making an antenna and the antenna itself is described, where the antenna comprises a first region having a first refractive index and a second region having an additional negative one, such that radiation outside the second region is reproduced in the first region.
Abstract: A method for making an antenna and the antenna itself are described. The antenna comprises a first region having a first refractive index and a second region having a negative refractive index, the second region substantially surrounding the first region, such that radiation outside the second region is reproduced in the first region.
Journal Article•
01 Jan 2003
TL;DR: In this paper, the authors have developed a highly anisotropic magnetic metamaterial that exhibits strongly negative permeability, and have investigated the characteristics of a hexagonal prism of the material in this regime by measuring the magnetic field components transmitted through the prism from a small dipole source.
Abstract: We have developed a highly anisotropic magnetic metamaterial that exhibits strongly negative permeability. The material consists of an array of Swiss Roll structures, resonant near 21.3 MHz, with a peak value of relative permeability |μ|~35. Above the resonant frequency, the permeability is negative (μ'~-17), and remains negative up to the magnetic "plasma frequency" at 29.75 MHz. We have investigated the characteristics of a hexagonal prism of the material in this regime of negative permeability, by measuring the magnetic field components transmitted through the prism from a small dipole source. A rich mode structure is observed, with no evidence of granularity due to the underlying Swiss Rolls. We have used the effective medium model to describe the propagation of electromagnetic radiation through an anisotropic magnetic medium, and find that it is able to interpret all the salient features of the transmitted field patterns. (6 pages)
06 Jun 2003
TL;DR: In this article, a slab of material with refractive index n = -1 behaves like a perfect lens, and the concept of layering the lens can improve resolution in lossy systems.
Abstract: A slab of material with refractive index n = -1 behaves like a perfect lens. Here we develop the concept showing how layering the lens can improve resolution in lossy systems, and proposing new lenses with magnified images.
Patent•
26 Mar 2003TL;DR: In this article, a mobile phone has an antenna which includes magnetically permeable material 1 to 4 surrounded by coil 5 connected to an r.f. source and/or receiver, which results in reduced absorption of the evanescent i.e. nonradiative field of the antenna in the user.
Abstract: A mobile communication apparatus such as a mobile phone has an antenna which includes magnetically permeable material 1 to 4 surrounded by coil 5 connected to an r.f. source and/or receiver. Unlike the normal dipole antenna of a mobile phone, the magnetic antenna of the invention results in reduced absorption of the evanescent i.e. non-radiative field of the antenna in the user. The antenna is preferably made up of an array of several small components having inductance and capacitance, the component dimension in one direction being less than the wavelength of radiation in which the apparatus is designed to operate.