Enhancing Optical Gradient Forces with Metamaterials

We demonstrate how the optical gradient force between two waveguides can be enhanced using transformation optics. A thin layer of double-negative or single-negative metamaterial can shrink the interwaveguide distance perceived by light, resulting in a more than tenfold enhancement of the optical force. This process is remarkably robust to the dissipative loss normally observed in metamaterials. Our results provide an alternative way to boost optical gradient forces in nanophotonic actuation systems and may be combined with existing resonator-based enhancement methods to produce optical forces with an unprecedented amplitude.Comment: 5 pages, 4 figures; supplemental information available from AP

Miniaturization of photonic waveguides by the use of left-handed materials

We propose the use of a left-handed material in an optical waveguide structure to reduce its thickness well below the wavelength of light. We demonstrate that a layer of left-handed material, added to the cladding of a planar waveguide rather than to its core, allows for good light confinement in a subwavelength thin waveguide. We attribute the observed behavior to the change in phase evolution of electromagnetic waves in the guide. This technique can be used for the miniaturization of photonic integrated circuits.Comment: 4 pages, 4 figure

Frequency converter implementing an optical analogue of the cosmological redshift

According to general relativity, the frequency of electromagnetic radiation is altered by the expansion of the universe. This effect--commonly referred to as the cosmological redshift--is of utmost importance for observations in cosmology. Here we show that this redshift can be reproduced on a much smaller scale using an optical analogue inside a dielectric metamaterial with time-dependent material parameters. To this aim, we apply the framework of transformation optics to the Robertson-Walker metric. We demonstrate theoretically how perfect redshifting or blueshifting of an electromagnetic wave can be achieved without the creation of sidebands with a device of finite length.Comment: 6 pages, 3 figure

Negative diffraction pattern dynamics in nonlinear cavities with left-handed materials

We study a ring cavity filled with a slab of a right-handed material and a slab of a left-handed material. Both layers are assumed to be nonlinear Kerr media. First, we derive a model for the propagation of light in a left-handed material. By constructing a mean-field model, we show that the sign of diffraction can be made either positive or negative in this resonator, depending on the thicknesses of the layers. Subsequently, we demonstrate that the dynamical behavior of the modulation instability is strongly affected by the sign of the diffraction coefficient. Finally, we study the dissipative structures in this resonator and reveal the predominance of a two-dimensional up-switching process over the formation of spatially periodic structures, leading to the truncation of the homogeneous hysteresis cycle.Comment: 8 pages, 5 figure

Polarization-mode hopping in single-mode vertical-cavity surface-emitting lasers: Theory and experiment.

In this paper, we present a theoretical and experimental analysis of stochastic effects observed in polarization switching vertical-cavity surface-emitting lasers. We make a thorough comparison between theoretical predictions and experiments, comparing measured quasipotentials and dwell times. The correspondence between our theoretical model based on stochastic intensity rate equations and the experiments is found to be very good

Anomalous transport coefficients in a turbulent plasma

A general self-consistent framework is developed for the calculation of transport coefficients in a collisionless, weakly turbulent plasma. These coefficients characterize the response to a perturbation away from a quasi-steady turbulent state, which is assumed to exist as a result of the stabilization of the linear instabilities. It is shown that a purely hydrodynamical description does not exist for plasmas: the macroscopic picture must include non-conserved quantities, which lead to the plasmadynamical (or ‘two-fluid’) picture of the system. The number of independent transport coefficients, necessary for the macroscopic characterization of the plasma, is correspondingly increased as compared with a two-component mixture of two ordinary fluids. The typical turbulent contributions to the transport coefficients are clearly exhibited. © 1978, Cambridge University Press. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Kinetic theory of the plasma-dynamical modes and the transport coefficients of a relativistic plasma

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Analytical approximation for the quantum-well gain and refractive-index spectra of vertical-cavity surface-emitting lasers including the effect of uniaxial planar stress

12 pages, 5 figures.-- PACS nr.: 42.55.Px.Starting from a microscopic model in the free-carrier approximation, we derive an analytical approximation for the optical susceptibility of uniaxially stressed quantum-well lasers at low temperatures by neglecting second-order contributions of the band-mixing phenomenon. The resulting polarization-dependent peak gains, differential peak gains, transparency carrier densities, and linewidth enhancement factors as induced by the uniaxial planar stress are discussed.The authors acknowledge the European RTN network VISTA (Contract No. HPRN-CT-2000-00034) and the COST 288 action. J. D. and G. V. acknowledge the FWO (Fund for Scientific Research—Flanders) for their fellowships and for project support. On the Belgian side this work was supported by the Interuniversity Attraction Pole program (IAP V/18), the Concerted Research Action “Photonics in computing” and the Research Council of the Vrije Universiteit Brussel. S. B. acknowledges financial support from Ministerio de Ciencia y Tecnología (Spain) through project TIC2002-04255-C04-03.Peer reviewe

Relativistic plasma-dynamical equations and plasma-dynamical normal modes

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

On the relativistic plasma-dynamical and hydrodynamical normal modes

SCOPUS: ar.jinfo:eu-repo/semantics/publishe