Showing papers by "John B. Pendry published in 1997"
TL;DR: De Heer et al. as mentioned in this paper presented an effective medium theory in order to analyze the reported optical properties of aligned carbon nanotube films, based on photonic band structure calculations and allowing treatment of complex media consisting of particles that interact strongly.
Abstract: We present an effective medium theory in order to analyze the reported optical properties of aligned carbon nanotube films [W. A. de Heer et al., Science 268, 845 (1995)]. This methodology is based on photonic band structure calculations and allows treatment of complex media consisting of particles that interact strongly. We also develop a simple Maxwell-Garnett type approach for studying this system. In comparing the results of both mean field theories, we demonstrate that the inclusion of the full electromagnetic coupling between the nanotubes, as our numerical scheme does, is necessary for a complete explanation of the experimental data.
253 citations
TL;DR: In this article, the authors consider two featureless surfaces at T = 0, defined only by their respective dielectric functions, separated by a finite distance, and ask the question of whether they can experience any friction when sheared parallel to their interface.
Abstract: We consider two perfectly smooth featureless surfaces at T = 0, defined only by their respective dielectric functions, separated by a finite distance, and ask the question of whether they can experience any friction when sheared parallel to their interface. We find large frictional effects comparable to everyday frictional forces provided that the materials have resistivities of the order of and that the surfaces are in close proximity. The friction depends solely on the reflection coefficients of the surfaces for electromagnetic waves and its detailed behaviour with shear velocity and separation is dictated by the dispersion of the reflectivity with frequency.
224 citations
TL;DR: In this paper, a new formalism for calculating the Green's function for Maxwell's equations is presented, which is used to calculate the spontaneous emission rate as a function of the distance to a material surface.
Abstract: We present a new formalism for calculating the Green's function for Maxwell's equations. As our aim is to apply our formalism to light scattering at surfaces of arbitrary materials, we derive the Green's function in a surface representation. The only requirement on the material is that it should have periodicity parallel to the surface. We calculate this Green's function for light of a specific frequency and a specific incident direction and distance with respect to the surface. The material properties entering the Green's function are the reflection coefficients for plane waves at the surface. Using the close relationship between the Green's function and the density of states (DOS), we apply our method to calculate the spontaneous emission rate as a function of the distance to a material surface. The spontaneous emission rate can be calculated using Fermi's Golden Rule, which can be expressed in terms of the DOS of the optical modes available to the emitted photon. We present calculations for a finite slab of cylindrical rods, embedded in air on a square lattice. It is shown that the enhancement or suppression of spontaneous emission strongly depends on the frequency of the light.
54 citations
TL;DR: In this paper, isolated dielectric spheres support resonant electromagnetic (EM) modes which are analogous to electronic orbitals and can form bonding or anti-bonding interactions between neighbouring spheres.
Abstract: Isolated dielectric spheres support resonant electromagnetic (EM) modes which are analogous to electronic orbitals and, like their electronic counterparts, can form bonding or anti-bonding interactions between neighbouring spheres. By irradiating the system with light at the bonding frequency an attractive interaction is induced between the spheres. We suggest that by judicious selection of bonding states we can drive a system towards a desired structure, rather than rely on the structure dictated by gravitational or Van der Waals forces, the latter deriving from the zero point energy population of a state.
43 citations
TL;DR: In this paper, the effect of scanning transmission electron microscopy electrons with composite systems is investigated by following a mean-field theory of the effective response function, and expressions for the inverse longitudinal dielectric function of isolated spheres and cylinders are derived.
Abstract: The interaction of scanning transmission electron microscopy electrons with composite systems is investigated by following a mean-field theory of the effective response function. Expressions for the inverse longitudinal dielectric function of isolated spheres and cylinders are derived. Experimental valence loss spectra from SiO2 polymorphs are analyzed and the insensitivity of the plasmon peak to the density of the material is explained. @S0163-1829~97!02715-X#
19 citations
TL;DR: In this paper, the authors consider two featureless surfaces at T = 0, defined only by their respective dielectric functions, separated by a finite distance, and ask the question whether they can experience any friction when sheared parallel to their interface.
Abstract: We consider two perfectly smooth featureless surfaces at T=0, defined only by their respective dielectric functions, separated by a finite distance, and ask the question whether they can experience any friction when sheared parallel to their interface. We find large frictional effects comparable to everyday frictional forces provided that the materials have resistivities of the order of 1 m-Ohm and that the surfaces are in close proximity. The friction depends solely on the reflection coefficients of the surfaces to electromagnetic waves and its detailed behaviour with shear velocity and separation is dictated by the dispersion of the reflectivity with frequency.
19 citations
TL;DR: In this paper, an adaptive coordinate transformation was used to accurately model the shape of the SNOM tip and to increase the transmitted light through the tip by introducing a metal wire into the center of the tip, which converts the tip into a coaxial cable.
Abstract: In this paper we consider the application of electromagnetic theory to the analysis of the Scanning Near-field Optical Microscope (SNOM) in order to predict experimentally observable quantities such as the transmission or reflection coefficients for a particular tip-surface configuration. In particular we present the first application of a transfer matrix based calculation to this challenging problem by using an adaptive coordinate transformation to accurately model the shape of the SNOM tip. We also investigate the possibility of increasing the transmitted light through the SNOM tip by introducing a metal wire into the centre of the tip. This converts the tip into a coaxial cable. We show that, in principle, this can dramatically improve the transmission characteristics without having a detrimental effect on the resolution.
19 citations
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5 citations
TL;DR: In this article, an adaptive co-ordinate transformation was used to accurately model the shape of the SNOM tip, which can dramatically improve the transmission characteristics without having a detrimental effect on the resolution.
Abstract: In this paper we consider the application of electromagnetic theory to the analysis of the Scanning Near-field Optical Microscope (SNOM) in order to predict experimentally observable quantities such as the transmission or reflection coefficients for a particular tip-surface configuration. In particular we present the first application of a transfer matrix based calculation to this challenging problem by using an adaptive co-ordinate transformation to accurately model the shape of the SNOM tip.
We also investigate the possibility of increasing the transmitted light through the SNOM tip by introducing a metal wire into the centre of the tip. This converts the tip into a co-axial cable. We show that, in principle, this can dramatically improve the transmission characteristics without having a detrimental effect on the resolution.
1 citations
TL;DR: In this paper, isolated dielectric spheres support resonant electromagnetic modes analogous to electronic orbitals and, like their electronic counterparts, can form bonding or anti-bonding interactions between neighbouring spheres.
Abstract: Isolated dielectric spheres support resonant electromagnetic modes which are analogous to electronic orbitals and, like their electronic counterparts, can form bonding or anti-bonding interactions between neighbouring spheres. By irradiating the system with light at the bonding frequency an attractive interaction is induced between the spheres. We suggest that by judicious selection of bonding states we can drive a system towards a desired structure, rather than rely on the structure dictated by gravitational or Van der Waals forces, the latter deriving from the zero point energy population of a state.