This PDF file contains the front matter associated with SPIE Proceedings Volume 6638, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

Fabrication of three-dimensional negative refractive index materials in the visible range faces numerous technological challenges. On the other hand, many new concepts and device ideas in the optics of metamaterials may be demonstrated much easier in two spatial dimensions using surface plasmon polaritons. Here we demonstrate these concepts and devices using novel multilayer two-dimensional photonic materials consisting of alternating layers of positive and negative refractive index. By changing composition and geometry of the layers, the effective anisotropic refractive index of the material may be continuously varied locally from large negative to large positive values. This approach may find applications in many novel nanophotonic devices, which enable efficient control of light propagation on submicrometer scale. This becomes possible because of the considerably improved figure of merit of the plasmonic metamaterials compared to the typical figures of merit of their three-dimensional counterparts.

We report on experimental realization of different metal-insulator geometries that are used as plasmonic waveguides guiding electromagnetic radiation along metal-dielectric interfaces via excitation of surface plasmon polaritons (SPPs). Three configurations are considered: metal strips, symmetric nanowires and nanowire pairs embedded in a dielectric, and metal V-shaped grooves. Planar plasmonic waveguides based on nm-thin and μm-wide gold strips embedded in a polymer that support propagation of long-range SPPs are shown to constitute an alternative for integrated optical circuits. Using uniform and thickness-modulated gold strips different waveguide components including reflecting gratings can be realized. For applications where polarization is random or changing, metal nanowire waveguides are shown to be suitable candidates for efficient guiding of arbitrary polarized light. Plasmonic waveguides based on metal V-grooves that offer subwavelength confinement are also considered. We focus on recent advances in manufacturing of nanostructured metal strips and metal V-grooves using combined UV, electron-beam and nanoimprint lithography.

Optical metamaterials characterized by several unique properties are introduced and characterized. The structures comprise continuous metal films sandwiched between dense periodic arrays of optically thin metal strips or patches separated by a small distance. The structures' electromagnetic properties are described by means of a modification of the cavity model typically used to characterized microwave patch antennas. It is shown that the presented structures can operate as negative index metamaterials that comprise deeply subwavelength periodic unit cells, are tunable for operation in the near-infrared and visible spectra, and can be manufactured using standard methods and materials. In addition, the presented structures can operate as an optical filter that, due to the presence of several resonances, transmits fields for certain (controllable) wavelength bands, which are (nearly) independent of the angle of incidence and polarization. The presented structures also can support arbitrary polarized surface waves that can have a high wavenumber and can exhibit unusual dispersion relations.

We have demonstrated that an addition of highly concentrated rhodamine 6G chloride dye to the PMMA film adjacent to a silver film causes three-fold reduction of the imaginary part of the dielectric constant of Ag (absorption loss in metal) and 30% elongation of the propagation length of surface plasmon polaritons (SPP). The possibility to elongate the SPP propagation length without optical gain opens a new technological dimension to low-loss nanoplasmonics.

The application of the magnetic metamaterials with positive (over one) permeability is proposed. The Brewster effect is one of the methods to eliminate unwanted reflection occurred at the material boundary of different indices. The message in this paper is that the magnetic responses of the metamaterial enable us to realize the Brewster effect not only for p-polarized light but also for s-polarized one. This new finding has the significant consequence that if we could induce the Brewster effect for both p- and s-polarized light simultaneously, the light could pass though the material boundary without any reflection loss at all. Based on this idea, we theoretically demonstrate the Brewster windows for both polarizations by introducing a uniaxial magnetic metamaterial whose values of the permittivity and permeability depend on the direction of the material. Numerical simulations prove that this metamaterial-based optical device realizes the reflectionless light transmission through the interface between vacuum and glass.

We introduce an efficient method for slowing and stopping/storing light, which is based on wave propagation along a slowly axially varying, adiabatically tapered, negative refractive index metamaterial heterostructure. We analytically show that the present method can, in principle, simultaneously allow for broad bandwidth operation (since it does not rely on group index resonances), large delay-bandwidth products (since a wave packet can be completely stopped and buffered indefinitely) and high, almost 100%, in/out-coupling efficiencies. Moreover, by nature, the presented scheme invokes solid-state materials and, as such, is not subject to low-temperature or atomic coherence limitations. This method for trapping photons conceivably opens the way to a multitude of hybrid, optoelectronic devices to be used in 'quantum information' processing, communication networks and signal processors, and may herald a new realm of combined metamaterials and slow light research.

We analyze linear and nonlinear propagation in negative index materials by starting from a dispersion relation and by deriving the underlying partial differential equations (PDEs). Transfer function for propagation is also derived in spatial frequency domain. Using existing numerical methods, based on fast Fourier-Bessel transforms, we study the stability of the solitary wave solutions. Nonlinearity and dispersion management are then incorporated to find stable solutions of the underlying PDEs.

Recently there has been developed a homogenization theory of photonic crystals, based on the averaging of the Maxwell Equations within the unitary cell. It leads to the bianisotropic response with the electric displacement D and the magnetic induction B vectors both depending linearly on the electric E and magnetic H fields. Despite the generality of this theory, the case of naturally magnetic ingredients has not been considered. For this reason, in this work we extend the aforementioned theory in this sense. In this way the ingredients of the unitary cell are characterized by a permeability, in addition to a generalized complex conductivity. These parameters are assumed to be given for every position in the unitary cell of the photonic crystal. We conclude that in the presence of naturally magnetic ingredients the medium response is still bianisotropic, but now the material dyadics depend on both the permeability and complex conductivity. Numerical results are given for the case of a one-dimensional photonic crystal with ferrite layers.

Realizable artificial medium with negative permittivity, permeability and refractive index are fabricated by introducing inclusions significantly smaller than the wavelengths of excitation into an archival host medium. Negative refractive index media normally posses a small degree of chirality associated with the split-rings. However in order to enhance the chirality of the artificial media, the split rings can be replaced by spirals. Recent work has shown that well controlled chiral media can be fabricated using available semiconductor techniques that have been modified to produce these structures. Specifically the glancing angle deposition technique (GLAD) has been shown to be well suited to producing these types of chiral structures. Novel devices made from metamaterials that also possess chirality are considered. When chiral properties are included in a negative refractive index slab, with n = -1, two rays are refracted in the slab. The distance between the two corresponding focal lines is determined by the magnitude of the chiral parameter. Thus this negative refractive index lens can also be used to measure the chiral parameter. At the focal lines small cross polarized components also exist. Based on the complete model expansion of the field at the chiral-chiral (or free space-chiral) interface it is shown that line sources also excite several species of lateral waves that are associated with total internal reflection. Since the refractive index is assumed to be negative, rays incident upon the chiral slab at the critical angles for total internal reflection, θ₁ and θ₂, are refracted parallel to the interface in the backward direction, resulting in θ^R₁ and θ^L₁ equal to -90°. Thus the image and the source are on the same side of the negative refractive index chiral slab and the device behaves like a reflector.

Photonic technologies hold the promise of transformative advances in the telecommunications, aerospace, and computing industries. In particular, organic materials displaying electro-optic coefficients an order of magnitude larger than the current industry standard inorganic materials (r₃₃ ≥ 300 pm/V) may hold the key to the development of cheap, high bandwidth, and highly integratable electro-optic devices. The pertinent linear and nonlinear optical properties of such organic second-order nonlinear optical materials are highly dependant on their dielectric properties as well as the extent of dipolar order that can be created. Here, theoretical approaches to the simulation of highly active organic electro-optic materials are described. Such simulations assist understanding and may be used to predict optical properties facilitating the rational design process. Improved ordering schemes, such as laser-assisted electric-field-poling may help in the translation of large chromophore hyperpolarizability values into large r₃₃. Recent results also suggest that incorporation of these improved organic materials into new hybrid organic/silicon device designs may lead to dramatically reduced device operational voltages and create opportunities for the development of new device functionality.

Optical absorption spectra of poly(thienylenevinylene) (PTV) conjugated polymers are measured at room temperature in spectral range 400 to 800 nm. A dominant peak located at 575 nm and a prominent shoulder at 614 nm are observed. Equilibrium atomic geometries of PTV conjugated polymers are studied by first principles density functional theory (DFT). Electron energy structure is obtained through self-consistent solution of eigen energy problem using ab initio ultrasoft pseudopotentials and generalized gradient approximation method. This is a non traditional approach for complex organic systems which is shown to be very promising especially for optical simulations. Linear optical absorption is calculated within Random Phase Approximation (RPA) picture. By comparative analysis of experimental and theoretical data it is demonstrated that dominant contribution to the optical excitations of PTV in visible spectral range are related to the delocalized electrons within the polymer chains. Obtained optical data together with equilibrium geometry analysis indicate that interchain interactions substantially effect electronic structure and optical absorption of PTV conjugated polymers.

We develop the ray optic Hamiltonian for a cylindrically anisotropic medium such as the hyperlens using the semiclassical approximation, which reveals an interesting spiralling behaviour of ray trajectories and also gives an alternative explanation to the subdiffraction far field imaging behaviour of the device. The Hamiltonian can be further used to derive the material parameters needed for non magnetic cloaking. Numerical simulations of gaussian beam scattering from these devices confirm the respective semiclassical results.

Sculptured thin films (STFs) are porous thin films manufactured by physical vapor deposition processes, and possess a morphology that is engineered at the nanoscale. When a circularly polarized plane wave is obliquely incident on a chiral STF, the Maxwell stress dyadic exhibits a decreasing periodic variation across the thickness of the film. Normal and tangential surface tractions exist on the two faces of the chiral STF, as well as a net normal pressure across the film. These stresses are affected by the incidence angle of light, and are maximized when (i) the incident plane wave and the chiral STF are co-handed, (ii) the wavelength falls within a regime called the Bragg regime, (iii) the ratio of film thickness to the structural period of the chiral STF reaches a saturation value, (iv) the deviation from normal incidence is small, (v) the loss factor in the chiral STF is as low as possible, and (vi) the vapor incidence angle is optimally chosen during film deposition.

We studied trends in three measures of both duration and average speed of optical videopulses transmitted through chiral sculptured thin films (STFs). The films, a class of nanoengineered materials which consist of parallel helical nanowires grown on a substrate, were taken to be linear or nonlinear with an intensity-dependent refractive index. We used a finite-difference algorithm to compute the evolution of the pulse shapes in the time domain. The durations of videopulses transmitted through chiral STFs tended to decrease with increasing carrier wavelength, while the average speeds tended to increase or remain roughly constant with increasing carrier wavelength. The durations and average speeds were similar irrespective of whether the incident pulse possessed a left or right circularly polarized carrier plane wave. That is, the circular Bragg phenomenon−due to a circular polarization dependent photonic bandgap exhibited by chiral STFs over a bandwidth called the Bragg regime−did not affect the results to any meaningful extent, in contrast to previous work. We attribute this finding to the wide bandwidth of the incident pulses swamping the Bragg regime.

A discussion of gain control up to the THz frequency range is presented together with a study of diffraction-managed solitons in metamaterials. Full dynamical simulations are used at every stage to illustrate the principles being evolved. An interesting approach based upon the mapping of the complex frequency-plane onto the complex wave number-plane is given as a way of demonstrating whether the offset of loss by using gain leads to a stable material. Nonlinear behaviour is addressed through the possibility of soliton formation under the conditions for which nonlinear diffraction can play a role whenever an attempt to manage the diffraction is made with a suitable combination of left-handed and right-handed materials. All of this activity requires the modeling of curious artificial molecules but the computational outcomes inspire confidence that is exemplified with exciting illustrations. The remit of control, exercised through external influences such as an applied magnetic field, and cavity formation is briefly explored.

We explore the perspectives offered by nanoplasmonic metamaterials for manipulation of optical signals at the nanoscale. It is shown that in contrast to conventional dielectric waveguides, plasmonic and anisotropy-based waveguides support a number of highly-confined optical modes even when the waveguide size is much smaller than the wavelength. The effective modal indices in these systems can be either positive or negative and are strongly affected by material composition and waveguide size, providing a mechanism for manipulating the phase velocity and diffraction limit at the nanoscale. In active metamaterials, the combined effect of waveguide- and material-induced dispersions leads to a versatile control over the group velocity which can be changed from negative to large or small (in comparison with the speed of light in vacuum) positive values by a relatively weak modulation of material properties. In the end, the active metamaterial provide a unique platform for independent manipulation of group and phase velocities of electromagnetic radiation in sub-diffraction areas.

We develop a rigorous theory of the enhancement of spontaneous emission from a light-emitting device via coupling the radiant energy in and out of surface plasmon polaritons (SPPs) on the metal-dielectric interface. We show that while the efficiency of coupling into the SPP mode can be quite high, the radiative efficiency of the SPP itself is relatively low, with a substantial fraction of the energy lost in the metal. Using the GaN/Ag system as an example we obtain easy-to-interpret analytical results that unequivocally indicate that using SPP pays off only for emitters that have medium-to-low luminescence efficiency; thus the SPP applications should be limited to those in sensing and analysis rather than in the development of efficient light sources.

The context of this work is the development of solid state materials with optimized microstructures for investigation of the random laser emission. We focused our attention on dye doped silica whose porosity allows controlling the light transport mean free path. Synthesized materials were silica monoliths prepared through sol-gel processing in the presence of a polymer that induces porosity through a spinodal phase separation. This technique allows the preparation of bulk samples with a controlled pore size varying from several microns to less than 100 nm. These samples were doped through impregnation with a naphthalimide fluorescent dye solution. Homogeneous dispersion of the dye was achieved using a silanated derivative leading to its homogeneous deposition as a thin film at the surface of the pores. This gives strongly fluorescent and diffusive materials. Optical properties of the samples were characterized using the 425.84 nm line of a dye laser. FWHM reduction of the sample emission was observed as a function of the pumping power, showing a typical behavior for a random laser in the weakly localized regime. Due to the versatility of the synthesis, the efficiency of the random lasing effect was investigated as a function of the materials microstructure.

A nano-scaled coupled-waveguide coupler based on the guidance of surface plasmon-polaritons (SPPs) is proposed, designed and simulated at optical frequencies. The basic structure of the coupler comprises layered dielectric materials and thin silver films, which serve as two stacked nano-transmission lines to achieve broadside coupling. The key property of this design is that it operates based on the principle of contra-directional coupling between a left-handed and a right-handed guided wave, giving rise to supermodes that are characterized by complex-conjugate propagation constants (even in the absence of losses), where the attenuation constant signifies the rate of coupling instead of the conventional power dissipation. The resulting exponential attenuation along the coupler leads to dramatically reduced coupling lengths compared to previously reported co-directional SPP couplers (e.g. from millimeters to sub-microns). Given its size, the device lends itself to form the building block of a functional matrix such as a switching array in nanophotonics applications, for example. In order to verify the contra-directional coupling theory and to characterize our design, we also propose and examine several possible excitation schemes, such as using a plasmonic dipole antenna and a grating structure to excite the SPP mode. Additionally, a measurement topology utilizing a curved plasmonic waveguide is also presented in this paper.

We propose an approach to far-field optical imaging beyond the diffraction limit. The proposed system allows image magnification, is robust with respect to material losses and can be fabricated by adapting existing metamaterial technologies in a cylindrical geometry.

Optical properties of a new kind of metamaterials based on hierarchically organized mirror channels with semitransparent walls, metamirror structures (MMS) are considered. Despite the difference in physical mechanisms, some properties of MMS i.e. transmission and reflection are close to that exhibited by left-handed materials. The ray tracing is considered for different MMS geometries and types. It is shown that one-step reflective 2D MMS based on rectangular elementary cells being properly curved possess lens properties and MMS lens generalized law is derived. Properties of a mirror lens prototype with the finite meta-focus position made from one layer 2D MMS with reflecting walls are evaluated theoretically and experimentally. Micro-machine mirror systems and modified macroporous structures are discussed as mirror lens devices.

The Pockels effect can be used to tune the effective birefringence of ambichiral structures made of electro-optic materials with 42m point group symmetry, when a dc electric field is applied parallel to the axis of nonhomogeneity. The reflectances and transmittances of such an ambichiral structure can be calculated through the solution of a boundary-value problem. The Bragg resonance peaks, for different circular-polarized-incidence conditions, blueshift as the angle of incidence increases.

During the past several decades enormous effort has been dedicated to experimental and theoretical studies of metal-radical organic complexes. Equilibrium geometries and electron energy structure of divalent lead Pb(II) complexes with ortho-semiquinone radicals have been calculated by generalized gradient approximation method (GGA) within density functional theory (DFT). Optical absorption spectra were calculated within random phase approximation (independent particles picture). Predicted substantial modification of the absorption spectra in visible infrared regions is attributed to the atomic configuration changes and to modifications of electronic energy due to the metal-radical coupling. The results of the calculations are discussed in comparison with available experimental data on electron spin resonance spectra of Pb(II) with paramagnetic ortho-semiquinone ligands.