This PDF file contains the front matter associated with SPIE Proceedings Volume 6581, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

We study the scaling of negative magnetic response of the SRR from microwave to upper THz frequencies. We show, that the linear scaling breaks down for SRR sizes below the order of 1&mgr;m. This breakdown is due to the contribution of the finite electron mass to the inductance of the effective LC oscillator. While at microwave frequencies metals can be treated as near-perfect conductors, close to optical frequencies they rather constitute lossy negative dielectrics. We also study the scaling of the losses in SRR as well as the higher order excitations or plasmon modes and their magnetic response. We discuss the non-resonant diamagnetic response of the SRR and the corresponding corrections to the shape of the frequency dependent effective permeability of the metamaterial. We discuss the connection of recently suggested alternative negative index metamaterial designs in a unified picture.

In electrical engineering metamaterials have been developed that offer unprecedented control over electromagnetic fields. Here we show that general relativity lends the theoretical tools for designing devices made of such versatile materials. We consider media that facilitate space-time transformations and include negative refraction. Our theory unifies the concepts operating behind the scenes of perfect invisibility devices, perfect lenses, the optical Aharonov-Bohm effect and electromagnetic analogs of the event horizon, and may lead to further applications.

A strategy for achieving negative phase velocity (NPV) in a homogenized composite material (HCM) involves constituent material phases that do not support NPV propagation. The HCM and its constituent phases are isotropic dielectric-magnetic materials. The real parts of their permittivities are negative-valued whereas the real parts of their permeabilities are positive-valued (or vice versa). The constituent material phases are randomly distributed as spherical particles. The Bruggeman homogenization formalism indicates that the HCM can support NPV propagation, the extended Bruggeman homogenization formalism suggests that increasing the dimensions of the constituent particles diminishes the scope for NPV propagation in the HCM, and the strong-permittivity- fluctuation theory further shows that the propensity of the HCM to support NPV propagation is sensitive to the distributional statistics of the constituent material particles and diminishes as the correlation length increases.

We show that metamaterial constituted from periodic array of identical noble-metal binary nanoparticles embedded into dielectric host matrix can exhibit left-handed properties in optical frequency domain. In contrast to recent suggestions to use, for example, double periodic lattice of metal nanowires or lattice of nanoparticle loops (or necklaces) binarynanoparticle material utilizes lowest plasmonic eigenmodes (dipole and quadropole) providing necessary electric and magnetic responses in the system of binary particles. This makes possible to extend negative refraction region due to increasing of the corresponding resonances quality-factors in comparison to high multipole modes excited in nanoparticle necklaces. Using the well-known optical constants for noble metals we calculate the optical response of binary-particle metamaterials for silver, gold and copper in the wavelength range 350-1200nm. We find that silver is the most suitable material for the particles which provides left-handed properties of metamaterial for approximately 400-1100nm wavelengths (at different values of permittivity of the host) whereas the gold particles can lead to the negative refraction only in more narrow range 750-1100nm because of the greater losses in the particles. Copper nanoparticle array seems to be unable to produce left-handed metamaterial at all.

Maxwell's equations describe the classical electromagnetic properties of all systems, including metamaterials, which are periodic and highly inhomogeneous. In studies of metamaterials, however, one typically further assumes that their low-frequency properties are described by Maxwell's equations in an equivalent homogenous medium. Hence, tremendous recent efforts have focused on discovering structures with unusual properties in electrical permittivity and magnetic permeability tensors. Here we offer an alternative viewpoint, by designing three-dimensional metamaterials, which may be best described by effective uniform media that is non-Maxwellian. In the low-frequency limit, these metamaterials support multi-component effective fields, with the numbers of field-components designable by geometry. Our work indicates that the physics of metamaterials is far richer than previously anticipated. In particular, new effective low-energy theory with high symmetry can emerge from topological complexity alone.

Negative phase velocity materials are engineered media that are currently enjoying a surge of interest due to their interesting properties and potential applications, through negative refraction, to achieve cloaking that makes things invisible. The literature is alive with papers devoted to the design of suitable metamaterials and there is a particular desire to operate at THz frequencies and above. A full theory of gain control up to the THz frequency range is presented together with a comprehensive study of diffraction-managed solitons. There are aspects of control that can be achieved through externally imposed influences such as gyroelectromagnetic effects. Nonlinear behaviour is also intrinsic to the Holy Grail quest for complete control, coupled to the possibility of beneficial competition between damping and gain.

Metamaterials offer exotic electromagnetic possibilities, beyond those usually associated with conventional materials. Two general phenomenons associated with metamaterials have attracted much recent attention: negative- phase-velocity (NPV) propagation, and cloaking and invisibility. Relatively simple materials may (i) support NPV propagation, and (ii) offer concealment to a substantial degree, by means of translation at constant velocity. By virtue of the Minkowski constitutive relations, planewave propagation in a homogeneous, instantaneously responding, dielectric-magnetic material that is isotropic in the co-moving reference frame, can be classified as positive-, negative-, and orthogonal-phase-velocity (PPV, NPV, and OPV) propagation in a non-co-moving reference frame, depending upon the magnitude and direction of that reference frame's velocity relative to the material. The perceived lateral position of a transmitted beam, upon propagating at an oblique angle through a slab of homogeneous, instantaneously responding, isotropic, dielectric material, can be controlled via the velocity of the slab. Therefore, by appropriate choice of the slab's velocity, the transmitted beam can emerge from the slab with no lateral shift in position, and a substantial degree of concealment may be achieved.

The study of theoretical optical metamaterials provides no detail insight of the atomic and molecular level of bulk matter with respect to negative n. Instead, most theoretical research starts from a different point of departure; an elemental metallic artificial structure that exhibits R, L and C and thus resonance. Manipulating the size and the periodicity of such elements in a larger structure, the phase relationship of a propagating electromagnetic wave through it and for a specific range of frequencies causes the phase to move in opposite direction of the Pointing vector. This phenomenon, demonstrated for microwave but not for optical frequencies yet, has certain interesting properties among them negative permeability and negative dielectric constant. In this paper, in contrast to this approach, our point of departure is on the atomic level of matter based on which we express the negative dielectric constant &egr;(&ohgr;) in terms of frequency detuning and also in terms of atomic density and we derive the detuning conditions for &egr;(&ohgr;)<0. We believe that these conditions provide a useful guide towards the design of optical metamaterials.

Diffusion of hydrogen in metal-doped glasses leads to the reduction of metals and to the growth of metallic nanoparticles in the glass body that allows the formation of metamaterials. The nanoparticles grow due to the supersaturation of the glass matrix by neutral metals, whose solubility in glasses is low compared to initial concentration of metal ions. In some cases, these metallic nanoparticles are self-arranging to quasi-periodic layered structure. A theoretical analysis of the reactive hydrogen diffusion accompanied by the interdiffusion of protons, metallic ions and neutral metals allowed us to study the temporal evolution of the average size of the metallic nanoparticles and their spatial distribution. The developed model of the formation of metallic nanoparticles defines range of parameters providing the formation of layered structures of metallic inclusions in silver and copper doped glasses. The layered structure arises at relatively low supersaturation of the diffusion zone by a neutral metal as the result of the competition of the enrichment of the glass by neutral metal atoms via reducing of metal ions by diffusing hydrogen and the depletion of the glass by the metal atoms caused by their diffusion to the nanoparticles. The results of numerical calculations are compared with the data of optical spectroscopy of the glass-metal metamaterials containing silver and copper nanoparticles.

We present here an algorithm to evaluate the field in the near zone produced by a finite-size electromagnetic source in a periodic structure, referred to as the array scanning method (ASM) - FDTD method. Using a frequency-dependent silver permittivity model, obtained from measurement at optical and infrared frequencies, we implemented the corresponding modeling equations in the ASM-FDTD algorithm using the Z-transform technique. The developed algorithm is applied to the study of the enhanced radiation of a magnetic line source in a corrugated silver film, and the results indicate that the enhancement is due to the excitation of a leaky mode. We also show that other waves may be excited by the source depending on its location, and how this affects the radiation pattern.

A tunable MEMS sub-wavelength surface plasmonic apparatus is proposed based on localized surface-plasmon resonance effects. Optical tunneling is obtained through Surface Plasmon Polaritons (SPP) and Localized Surface Plasmon (LSP) by using a periodic sub-wavelength narrow-grooved metal-dielectric-metal (MDM) composite structure. Only p-polarized light can excite the SPP and LSP resonantly. The excited LSP mode with a strong field enhancement at the incident side grooves, resonantly excites the LSP mode on the other side of the thin structure. Then, with matched radiative modes, photons are radiated and tunneled. Nano/micro electromechanical actuation of small elastic deformations makes it possible to dynamically tune the localized surface plasmons via shape changes. Numerical simulations based on the Finite-Difference Time-Domain (FDTD) method are carried out on sub-wavelength structures and the results discussed. The MDM concept provides a new method to achieve real-time, dynamic tunable control and manipulation of light transmission and reflection via LSP which is different from novel tunable SPP apparatus where refractive index modulation is obtained using a voltage-controlled liquid crystal or tunable spaced air-gapped micro-prisms based on a convential SPP arrangement. This is important for the manipulation of LSP and plasmonic device design applications. Furthermore, a proposed Localized Surface Plasmon Resonance (LSPR) sensor mechanism with MDM-LSPR are demonstrated with numerical results. We believe that the MDM-LSPR is a novel principle for LSPR sensors in dielectric sensing for chemical or biologic applications which compares to current LSPR sensors with nano-particle LSPR and nanosphere lithography (NSL).

A novel phase-space method is employed for the construction of analytical stationary solitary waves located at the interface between a periodic nonlinear lattice of the Kronig-Penney type and a linear (or nonlinear) homogeneous medium. The method provides physical insight and understanding of the shape of the solitary wave profile and results to generic classes of localized solutions having a zero background or nonzero semi-infinite background. For all cases, the method provides conditions for the values of the propagation constant of the stationary solutions and the linear refractive index in each part in order to assure existence of solutions with specific profile characteristics. The evolution of the analytical solutions under propagation is investigated for cases of realistic configurations and interesting features are presented while their remarkable robustness is shown to facilitate their experimental observation.

The paper is concerned with the propagation characteristics of TE surface waves in a planer wave-guide structure of a lateral antiferromagnetic -non magnetic superlattices (LANS)film bounded by a nonlinear dielectric cover and a left handed substrate (LHM). In (LHM) substrate both permittivity and magnetic permeability are negative in definite frequency range. We study nonlinear dispersion properties of the TE surface waves and illustrate power flow variation with the wave index when both permittivity and magnetic permeability are negative. We found that surface waves are backward traveling and the wave power variation with the wave index shows bistability behavior.

In this work we report on structures operating as actively tunable filters or modulators for the terahertz spectral range. These devices can be described as one-dimensional photonic crystals with defects and are composed of quartz, MgO and GaAs thin platelets; the optically transparent materials (quartz and MgO) are used as Bragg mirrors forming a resonator and GaAs is placed inside this resonator. The tunability is achieved by photoexcitation of free carriers within the GaAs layer by an ultrashort laser pulse. The optical control of such devices features a very fast (sub-nanosecond) response which is attractive e.g. for future applications in telecommunications.

Tunable electromagnetic metamaterials can be designed through the incorporation of semiconducting materials. We present theory, simulation, and experimental results of metamaterials operating at terahertz frequencies. Specific emphasis is placed on the demonstration of external control of planar arrays of metamaterials patterned on semiconducting substrates with terahertz time domain spectroscopy used to characterize device performance. Dynamical control is achieved via photoexcitation of free carriers in the substrate. Active control is achieved by creating a Schottkey diode, which enables modulation of THz Transmission by 50 percent, an order of magnitude improvement over existing devices. Because of the universality of metamaterial response over many decades of frequency, these results have implications for other regions of the electromagnetic spectrum and will undoubtedly play a key role in future demonstrations of novel high-performance devices.

In this paper, we show how metamaterials can be used either to enhance the coupling values or to reduce the crosstalk between the strips of coupled microstriplines. Coupling between regular coplanar microstriplines, in fact, is limited, due to the small ratios between the characteristic impedances of even and odd TEM modes supported by the structure. The broadside configuration or the employment of an overlay are often utilized to overcome this limitation, leading, however, to more bulky components. On the other hand the coupling/crosstalk can be undesiderable in printed circuits. The employment of metamaterials with a negative real part of the permittivity is able to increase or decrease the coupling values, while keeping the profile of the structure very low. A quasi-static model of the structure is developed and physical insights on the operation of the proposed components and the role of the metamaterial loading are also given. Finally numerical results are shown for two proposed layouts.

Dielectric substrates supporting planar periodic subwavelength metamaterial-based metallic arrays and presenting frequency dispersive phase characteristics are applied to ultra-compact high-gain and high-directivity planar antennas. In this paper, different models of metamaterial-based surfaces introducing a zero degree reflection phase shift to incident waves are firstly studied numerically using finite-element method analysis where the bandwidth and operation frequency are predicted. These surfaces are then applied in a resonant Fabry-Perot type cavity and a ray optics analysis is used to design different models of ultra-compact high-gain microstrip printed antennas. Firstly, a cavity antenna of thickness &lgr;/60 based on the use of a microstrip patch antenna and two bidimensional metamaterial-based surfaces, the first one acting as a High Impedance Surface (HIS) and the second one acting as a Partially Reflecting Surface (PRS) is designed. This cavity is then optimized for easier fabrication process and loss reduction by the use of only one bidimensionnal composite metamaterial-based surface acting as a PRS. Secondly, another surface presenting a variable phase by the use of a non periodic metamaterial-based metallic strips array is designed for a passive low-profile steering beam antenna application. Finally, a switchable operation frequency cavity by the implementation of varicap diodes is designed and fabricated. All these cavity antennas operate on subwavelength modes, the smallest cavity thickness being of the order of &lgr;/60.

Magnetooptical effects in the metal/dielectric heterostructure, consisting of a thin metallic layer with the array of parallel subwavelength slits and a uniform dielectric layer magnetized perpendicular to its plane, are investigated. Calculations, based on the rigorous coupled-wave analysis of Maxwell's equations, demonstrate that in such structures the Faraday and Kerr rotation can be significantly enhanced in the near infrared optical range. It is possible by varying thickness of the magnetic film to make Faraday rotation and transmittance peaks coincident and achieve the increase in the Faraday effect by more than an order of magnitude at the transmittance of 40-45%. It is shown that the excitation of the surface plasmon polaritons and quasi-guided TM- and TE- modes in the dielectric layer mostly governs the enhancement of the Faraday rotation.

We report on experimental and theoretical investigation of birefringence of free-standing nanoporous anodic alumina membranes in the optical range. The value of birefringence is analyzed for the samples with different porosities by measuring polarization dependent transmission spectra at different angles of incidence. The experimental data are compared to the results of birefringence simulations in accordance with three simulation approaches: modified Bruggeman effective-medium approximation, Boundary conditions model, plane-wave expansion method. It is both experimentally and theoretically shown that birefringence value increases with porosity increasing in the low porosity region. The porous alumina samples under investigation possess greatest value of birefringence (0.062) up to date.

Renewed and growing interest in the field of surface plasmon polaritons (SPPs) comes from a rapid advance of nanostructuring technologies. The desired nanostructures are usually fabricated by electron- or ion-beam lithography. An alternative approach is the application of two-photon polymerization (2PP) or nonlinear lithography. Both these technologies are based on nonlinear absorption of near-infrared femtosecond laser pulses. With 2PP, the fabrication of three-dimensional micro-objects and photonic crystals with a resolution down to 100 nm is possible. In this contribution, we study applications of advanced femtosecond laser technologies for the fabrication of SPP structures. We demonstrate that resulting structures can be used for excitation, guiding, and manipulation of SPPs on a subwavelength scale. Characterization of these structures is performed by detection of the plasmon leakage radiation (LR). 2PP allows the fabrication of dielectric waveguides, splitters, and couplers directly on metal surfaces. The fabricated dielectric structures are also very efficient for the excitation of SPPs. Using these structures, excitation and focusing of the resulting plasmon field can be achieved.

We report a novel method for modeling the resonant frequency response of infra-red light, in the range of 2 to 10 microns, reflected from metallic spilt ring resonators (SRRs) fabricated on a silicon substrate. The calculated positions of the TM and TE peaks are determined from the plasma frequency associated with the filling fraction of the metal array and the equivalent LC circuit defined by the SRR elements. The capacitance of the equivalent circuit is calculated using conformal mapping techniques to determine the co-planar capacitance associated with both the individual and the neighbouring elements. The inductance of the equivalent circuit is based on the self-inductance of the individual elements and the mutual inductance of the neighboring elements. The results obtained from the method are in good agreement with experimental results and simulation results obtained from a commercial FDTD simulation software package. The method allows the frequency response of a SRR to be readily calculated without complex computational methods and enables new designs to be optimised for a particular frequency response by tuning the LC circuit.

Wave fronts of a Gaussian light pulse and a CW Gaussian beam refracted at the boundary of right- and left-handed media are modified due to material dispersion. Group velocity of a negatively refracted pulse is parallel to the direction of energy transport and anti-parallel to phase velocity. Positively refracted group front moves sideways with respect to negatively refracted phase front. We analyze modifications of light pulses of different spectra in effective media with different frequency dispersion curves. Analysis of dispersion effects is important because of possible applications in band separation and pulse compression in metamaterial devices. In 2D FDTD simulations we analyze evolution of CW Gaussian beams and short Gaussian pulses in an effective double negative material with dependence of permittivity and permeability functions on frequency corresponding to Drude material-dispersion model.

Photonic crystal (PhC) structures and photonic structures based on them represent nowadays very promising structures of artificial origin. Since they exhibit very specific properties and characteristics that can be very difficult (or even impossible) to realize by other means, they represent a significant part of new artificially made metamaterial classes. For studying and modeling properties of PhC structures, we have applied, implemented and partially improved various complementary techniques: the 2D plane wave expansion (PWE) method, and the 2D finite-difference time-domain (FDTD) method with perfectly matched layers. Also, together with these in-house methods, other tools available in the field have been applied, including, e.g. MIT MPB (PWE), F2P (FDTD) and CAMFR (bidirectional expansion and propagation mode matching method) packages. We have applied these methods to several PhC waveguide structure examples, studying the effects of varying the key parameters and geometry. Such a study is relevant for proper understanding of physical mechanisms and for optimization and fabrication recommendations. Namely, in this contribution, we have concentrated on several examples of PhC waveguide structure simulations, of two types of guides (dielectric-rode type and air-hole type), with several geometries: rectangular lattice with either rectangular or chessboard inclusions. The modeling results are compared and discussed.

The concept of negative refraction promises to rewrite the electromagnetic textbooks due to its corresponding unprecedented properties including inverse Snell's law, inverse Doppler shift, and inverse Cherenkov radiation. Recently, the first demonstration of negative refractive index media (NRIM) was realized by D.R. Smith et al. who integrated two respective sets of sub-wavelength resonant structures (i.e., plasmonic wires and split-ring resonators) to exhibit negative electric permittivity and magnetic permeability simultaneously. More recently, other resonant structures made of a single set of unit cells also suggested negative refraction phenomena, enabling to ease the fabrication. Yet, all those resonant structures behave anisotropically and thereby, currently it is still challenging to realize negative refraction for different exciting incidences such as grazing-angle and normal incident configurations. In this paper, we design and simulate a monolithic set of double-layer resonant structures not only possessing negative refraction, but also simultaneously responding to both grazing-angle and normal incident excitations within microwave region. In accordance with the results of S-parameter simulation and the retrieved material properties, we clearly observe two allowed narrow bands to indicate the existence of pseudo-isotropic NRIM (PINRIM). Our results show that the designed monolithic set of double-layer structures can extensively broaden the valuable applications of negative refraction owing to its pseudo-isotropic response.

Features of the polarization, energy fluxes of proper inhomogeneous electromagnetic waves in a layer of absorbing uniaxial negative index metamaterial, and an exact solution of the corresponding boundary problem are investigated. A comparative analysis and modeling of optical properties of anisotropic conventional media and metamaterials is carried out. Conditions and possible advantages of a controlled transformation of the radiation characteristics by the metamaterial are analyzed.

Using the transfer matrix method we analyse the transmission of time-modulated Gaussian beam through the RHM-LHM layered structures with dispersive, lossy, and magnetic layers. The modulated parts of the beam are subject to a complex temporal and spatial shape transformation, which may be characterised in terms of spectral and spatial filtering, while the layered structure itself is entirely described with the respective transfer function or equivalently with the impulse response. Due to strong dispersion and absorption of the LHM layers, it is possible to identify higher order dispersion effects taking place within very short distances. This opens the possibility of designing novel filters capable of complex reshaping of the beam envelope.

A modal method with a transmission line formulation is employed to electromagnetic analysis of two types of photonic metamaterials. Effective parameters for an array of split ring resonators and plate-pairs are achieved via calculation of transmission and reflection coefficients and a retrieval procedure. Assuming spatial symmetries in the diffracted modes, computation time is reduced by a factor of 1/8 for the SRR and 1/64 for the plate-pair structure. The convergence criteria are investigated and advantages and disadvantages of the method are concluded.

The dispersion relation for polarized light transmitting through a one-dimensional superlattice composed of aperiodically arranged layers made of ordinary dielectric and negative refraction metamaterials is calculated with finite element method. Generalized Fibonacci, generalized Thue-Morse, double-periodic and Rudin-Shapiro superlattices are investigated, using their periodic approximants. Strong dispersion of metamaterials is taken into account. Group velocities and effective refraction indices in the structures are calculated. The self-similar structure of the transmission spectra is observed.

We investigate numerically transmittance of polarized electromagnetic wave through different binary multilayered structures made of left- and right-handed materials. The transmittance is calculated as a function of wavelength, incidence angle, refractive index and superlattices' parameters. The transfer matrix formalism is applied (tunnelling is accounted). Absorption and strong dispersion in left-handed metamaterials are taken into account. The results are presented in grey scale transmittance maps.

We investigate the appearence of non-Bragg band gaps in 1D fractal photonic structures, specifically the Cantor-like lattices combining ordinary positive index materials and dispersive metamaterials. It is shown that these structures can exibit two new type of photonic band gaps with self-similarity properties around the frequencies where either the magnetic permeability or the electric permittivity of the metamaterial is zero. In constrast with the usual Bragg gaps, these band gaps are not based on any interference mechanisms. Accordingly, they remain invariant to scaling or disorder. Some other particular features of these polarization-selective gaps are outline and the impact on the light spectrum produced by the level of generation of the fractal structure is analyzed.