This PDF file contains the front matter associated with SPIE Proceedings Volume 7756, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

We demonstrated lasing in localized optical resonances of deterministic aperiodic structures with pseudo-random morphologies. The localized lasing modes in the Rudin-Shapiro arrays of air nanoholes in GaAs membranes occur at reproducible spatial locations and their frequencies are only slightly affected by the structural fluctuations in different samples. Numerical study on the resonances of the passive systems and optical imaging of lasing modes enabled us to interpret the observed lasing behavior in terms of distinctive localized resonances in the two-dimensional Rudin- Shapiro structures. The deterministic aperiodic media with controllable structural and optical properties provide a novel platform, alternative to random lasers and different from photonic crystals lasers, for the engineering of multi-frequency coherent light sources suitable for technological integration.

Second harmonic generation in random structures is studied. It is shown that a second harmonic signal with a high intensity can be obtained by use of a localized field couple to extended, necklace, states.

Recently, metamaterial cloaks for the microwave frequency range have been designed using transformative optics design techniques and experimentally demonstrated. The design of these structures requires extreme values of permittivity and permeability within the device, which has been accomplished by the use of resonating metal elements. However, these elements severely limit the operating frequency range of the cloak due to their non-ideal dispersion properties at optical frequencies. In this paper we present designs to implement a simpler demonstration of cloaking, the carpet cloak, in which a curved reflective surface is compressed into a flat reflective surface, effectively shielding objects behind the curve from view with respect to the incoming radiation source. This approach eliminates the need for metallic resonant elements. These structures can now be fabricated using only high index dielectric materials by the use of electron beam lithography and standard cleanroom technologies. The design method, simulation analysis, device fabrication, and near field optical microscopy (NSOM) characterization results are presented for devices designed to operate in the 1400-1600nm wavelength range. Improvements to device performance by the deposition/infiltration of linear, and potentially non-linear optical materials, were investigated.

Light management in single and tandem solar cells is becoming increasingly important to optimize the optical and electro-optical properties of solar cells. After a short introduction to state-of-the-art light management approaches, different applications of photonic crystals for photon management in solar cells are reviewed and discussed concerning their applicability. Results on direction- and energy-selective filters for ultra-light-trapping, intermediate reflectors for optimal current matching in tandem cells, and photonic crystal coating for fluorescence collectors will be presented and discussed.

We present a microscopic theory of thermal emission from truncated photonic crystals and show that spectral emissivity and related quantities can be evaluated via standard bandstructure computations without any approximation. We then analyze the origin of thermal radiation enhancement and suppression inside photonic crystals and demonstrate that the central quantity that determines the thermal radiation characteristics such as intensity and emissive power is the area of the iso-frequency surfaces and not the density of states as is generally assumed. We also identify the physical mechanisms through which interfaces modify the potentially super-Planckian radiation flow inside infinite photonic crystals, such that thermal emission from finite-sized samples is consistent with the fundamental limits set by Planck's law. As an application, we further demonstrate that a judicious choice of a photonic crystal's surface termination facilitates considerable control over both the spectral and angular thermal emission properties. Finally, we outline design principles that allow the maximization of the radiation flux, including effects associated with the isotropy of the effective Brillouin zone, photonic band gap size and flatness of the band structure in the spectral range of interest.

We present two photonic crystal enabled platforms, exhibiting novel active optical phenomena. First, using a detailed theoretical and numerical analysis, we show how a Purcell-effect inspired nonlinear nanophotonic scheme could enable optimal and compact THz sources via optical difference frequency generation. Second, we show how electromagnetic one-way edge modes analogous to quantum Hall edge states, originally predicted by Raghu and Haldane in gyroelectric photonic crystals, can appear in more general settings. In gyromagnetic YIG photonic crystals operating at microwave frequencies, time-reversal breaking is strong enough that the effect is readily observable. We present our experimental results on this novel phenomenon.

Interference of light in a multilayer stack of metals and dielectrics, called metallo-dielectrics, can elicit unusual linear and nonlinear properties of these composite materials. This paper reports results on linear and nonlinear optical properties using various materials, especially super-resolution and nonlinear optical properties.

We report on the linear and nonlinear optical properties of Ag/Au multi-metal thin films and Fabry-Perot resonator cavities. The linear optical properties of these multi-metal layers, having different mass distributions and Ag/Au ratios with thicknesses around 15 nm, resemble those of electrically continuous metal layers. The optical losses introduced by interband transitions in the Au layers are reduced to achieve peak transmittances of 76 % around 550 nm. Using femtosecond-pulsed white-light continuum pump-probe experiments we show that the nonlinear optical response of such multi-metal layers is comparable to that of neat Au thin films. Low-finesse Fabry-Perot resonators fabricated with such multi-metal layers, combine the large NLO response of Au with a transmittance of 60% and a spectral bandwidth that covers the visible spectral range.

We report the hydrothermal synthesis of free-standing lithium niobate nanowires. We show that the versatile properties of bulk lithium niobate such as nonlinear optical effects can be exploited at the nanoscale. We describe the fabrication of polydimethylsiloxane (PDMS) microfluidics as well as indium tin oxide (ITO) electrodes with different design for dedicated applications. The control of microfluidic channel dimensions and the corresponding particle concentration is explored. Finally, the selection of fluidic conductivity for optimal dielectrophoretic trapping conditions is discussed.

We report on the nonlinear optical (NLO) transmittance and reflectance of a 20 nm-thick Ag film characterized by time-resolved white-light continuum pump-probe experiments. The change in complex permittivity Δε(t) is extracted and is fitted to the Drude model in the frequency domain and a two-temperature model in the time domain. A unified model is presented that fully describes the dynamic NLO response of a thin Ag film that can be incorporated easily into the modeling of more complex metal-dielectric multilayer structures designed to take advantage of the NLO response of Ag.

A novel technique based on the two polymer micro-transfer molding (2-P μTM) for fabricating one dimensional (1D) high aspect ratio nanoscale metallic structures is presented and experimental characterization is described. Glancing angle metal deposition and physical argon ion milling (etching) techniques were also employed in processing. The resulting metallic structures have high transmission (~80%) in the visible spectrum and have superior electrical conductivity (resistance from 2.4 -7.3 Ω) compared to standard indium-tin oxide (ITO) glass. Thus, the high aspect ratio metallic structures are a promising alternative with potentially superior performances to ITO glass as transparent electrodes for organic solar cells.

We demonstrate mid-infrared electroluminescence from intersublevel transitions in self-assembled InAs quantum dots coupled to surface plasmon modes on metal hole arrays. Subwavelength metal hole arrays with different periodicity are patterned into the top contact of the broadband (9-15 μm) quantum dot material and the measured electroluminescence is compared to devices without a metal hole array. The resulting normally directed emission is narrowed and a splitting in the spectral structure is observed. By applying a coupled quantum electrodynamic model and using reasonable values for quantum dot distributions and plasmon linewidths we are able to reproduce the experimentally measured spectral characteristics of device emission when using strong coupling parameters.

In this work we show room temperature continuous (CW) lasing at 1.5 μm in photonic crystal microcavities with a single layer of self-assembled quantum wires (QWRs). Low threshold values in the range of 1-20 μW (depending on the excitation type, pulsed or CW) have been measured, along high quality factors exceeding Q=55000 using L7-type photonic crystal microcavities. Solid-source molecular beam epitaxy has been used for the synthesis of the InP/InAs epitaxial material comprising a single layer of InAs QWRs. The main axis of the cavity is always parallel to the QWRs, which are more than 1ìm in length along the [1-10] direction. No lasing has been obtained for L7 cavities with axis parallel to the [110] (i.e., perpendicular to the direction of the QWRs), showing the strong one-dimensional character of the QWRs inside the photonic cavity. Under inhomogeneous pulsed excitation the lasing spectra show asymmetric lineshapes and peak splittings first in the μeV and later in the meV ranges as the excitation power is increased.

We report the detailed analysis on the phase discontinuity, field distribution, penetration depth and photon lifetime in 1D and 2D PC mirrors. Compared to classical distributed Bragg reflectors (DBRs), these new types of PC mirrors exhibit different phase discontinuties and slower phase changes over the high reflection bands for surface-normal incident beams. Fabry-Perot (FP) cavity designs were carried out based on these three types of dielectric reflectors. In PC mirror based FP cavities, we observed penetration depth of 2~4μm, which is related to the large phase discontinuity. On the other hand, due to the tight field confinement, the energy penetration depths were ~ 0.1μm in PC mirror based FP cavities, much lower than that in DBR based FP cavities. We will also report on the distinctively different field distribution behaviors in these cavities, which are critical in the design of various active optoelectronic devices.

We introduce extremely compact all-optical nonlinear switches based on Y-shaped plasmonic waveguides. We consider a Y-shaped structure, consisting of a subwavelength metal-dielectric-metal input waveguide branch connected to two metal-dielectric-metal output waveguide branches. The Y-shaped channel is embedded in a metallic film and filled with a Kerr nonlinear material. We show that such a device can be designed to function as a switch between the two output branches, controlled by the intensity of the incident light. We also show that the Y-shaped plasmonic structure can be used as a tunable optical splitter.

Optical properties of a three-dimensional composite medium consisting of an amplifying matrix with inclusion of silver nanoparticles of various shapes are investigated theoretically. Considering the case of an effective refractive index equal to one, condition for a transparent material, the amplification coefficient needed for compensating the losses is studied. It is shown that for the composite material with ellipsoidal inclusions the required gain coefficient is significantly less that for a composite medium with spherical inclusions.

We demonstrate the steering of coherent mid-infrared radiation through plasmonic structures consisting of a single sub-wavelength slit flanked by a periodic array of grooves, fabricated on GaAs substrates. We demonstrate control of steering angle by tuning the incident radiation, and study beam quality for the transmitted light. In addition, we demonstrate that small shifts in the refractive index of the GaAs substrate can actively control the steering angle of the transmitted light, opening a path towards the development of no-moving-parts plasmonic beam steering devices.

The refraction properties of photonic crystal lattices offers methods to control the beam steering of light through use of non-linear dispersion contours. In this paper new photonic crystal structures, such as the square and triangular superlattices, that provide novel refractive properties are analyzed. The property difference between rows in these structures is the hole radius Δr. The difference in hole sizes leads to observation of the superlattice effect, that is, a change in the refractive index Δn between opposite rows of holes. The index difference becomes a function of the size of the smaller r₂ hole area or volume due to the addition of the higher index background material compared to the larger r₁ holes. The difference in hole radii Δr = r₁ - r₂ is referred to as the static superlattice strength and is designated by the ratio of r₂/r₁. The superlattice strength increases as the ratio of r₂/r₁ decreases. The hole size modulation creates modified dispersion contours that can be used to fabricate advanced beam steering devices through the introduction of electro-optical materials and a controlled bias. A discussion of these superlattice structures and their optical properties will be covered, followed by both static and dynamic tunable device constructions utilizing these designs. Also, static tuning of the devices through the use of atomic layer deposition, as well as active tuning methods utilizing liquid crystal (LC) infiltration, sealed LC cells, and the addition of electro-optic material will be discussed.

We designed, fabricated and characterized MEMS-enabled mechanically-tunable photonic crystal lens comprised of 2D photonic crystal and symmetrical electro-thermal actuators. The 2D photonic crystal was made of a honeycomb-lattice of 340 nm thick, 260 nm diameter high-index silicon rods embedded in low-index 10 μm thick SU-8 cladding. Silicon input waveguide and deflection block were also fabricated for light in-coupling and monitoring of focused spot size, respectively. When actuated, the electro-thermal actuators induced mechanical strain which changed the lattice constant of the photonic crystal and consequently modified the photonic band structure. This in turn modified the focal-length of the photonic crystal lens. The fabricated device was characterized using a tunable laser (1400~1602 nm) and an infrared camera during actuation. At the wavelength of 1450 nm, the lateral light spot size observed at the deflection block gradually decreased 40%, as applied current increased from 0 to 0.7 A, indicating changes in focal length in response to the mechanical stretching.

We consider laser pulse propagation through the 2D nonlinear photonic structure or through the 1D layered nonlinear structure or though the homogeneous nonlinear plate. We have found out a self-formation of soliton if the intensity in focal waist of laser beam is greater than its critical value. In this case, the nonlinear localization of light energy inside the photonic crystal or the plate occurs. For 2D or 1D photonic structure the dependence of localized optical energy on the nonlinearity can be more monotonic in comparison with such dependence taking place for a nonlinear plate. Focusing of a laser beam in a medium and the properties of the photonic crystal has an influence on this dependence. Using the photonic crystal allows to realize the dependence, which is less sensitive to a fluctuation of the optical intensity in comparison with similar dependence for a homogeneous nonlinear plate The mode of unchanging of the beam profile on a transverse coordinate takes place after a passage of a longitudinal coordinate, at which a waist of focused laser beam achieves, if the intensity of the beam does not exceed some critical value. In this case a laser pulse propagates through the periodic structure in waveguide mode. Taking into account that for this mode the size of a beam is equal to transverse size of a photonic crystal layer one can easy to realize various channels of a transmission of laser energy. It may be important for the field of information technology. Similar mode of a propagation of a laser beam is absent for the homogeneous nonlinear plate. In this case the optical beam propagates without changing its transverse size. The results obtained can also be used for two-wave optical switching element that was proposed recently in [26] for an all-optical memory device.

A two-dimensional anisotropic annular photonic crystal structure is presented to obtain an absolute photonic band gap. This structure is composed of circular air holes and dielectric rods in a triangular lattice. Uniaxial crystal is introduced to photonic crystal with extraordinary axis parallel to the extension direction of rods. The role of each dielectric and geometric parameter is investigated and a mid-gap ratio above 35% is realized by the parameter optimization. Large gap favors the structure with negative uniaxial veins and positive uniaxial rods. As the air-hole radius scales up, the dielectric-rods radius to sustain the maximum band gap scales down. The positive uniaxial material Tellurium is used to achieve a large polarization-insensitivity gap.