This PDF file contains the front matter associated with SPIE Proceedings Volume 6988, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Excitation, focusing, and directing of surface plasmon polaritons (SPPs) with curved chains of bumps located on a metal surface is investigated both experimentally and theoretically. We demonstrate that, by using a relatively narrow laser beam (at normal incidence) interacting only with a portion of a curved stripe or chain of nanoparticles, one can excite an SPP beam whose divergence and propagation direction are dictated by the incident light spot size and its position along the structure. It is also found that the SPP focusing regime is strongly influenced by the chain inter-particle distance. Extensive numerical simulations of the configuration investigated experimentally are carried out for a wide set of system parameters by making use of the Green's tensor formalism and dipole approximation. Comparison of numerical results with experimental data shows good agreement with respect to the observed features in SPP focusing and directing, providing the guidelines for a proper choice of the system parameters. It was found that the focusing regime of SPPs is strongly influenced by the chain inter-bump distance, so that the focusing and directing effects with optimal properties can be obtained only when the chain inter-bump distance is smaller than the SPP wavelength. Following the experimental conditions, we have studied the role of the size of light spot exciting SPPs. Spectral dependence of the focusing waist is also numerically studied for gold surface taking into account the ohmic loss.

Two-photon induced photoluminescence (TPL) microscopy has been used to probe the local field of nanoantennas. We demonstrate that TPL imaging is directly correlated to the antenna electromagnetic mode computed with a full 3D solver. Furthermore, spectroscopic mode mapping while scanning the incident wavelength enables near-field spectroscopy of specific areas of the antenna response, providing a deeper insight into its resonant properties.

Surface enhanced Raman scattering (SERS) has been investigated for different molecules adsorbed on metallic nanostructures. The local field enhancements due to the confinement and resonances of surface plasmons, can reach many orders of magnitude. These field enhancements allow molecules to produce strong Raman spectra, although they have tiny Raman scattering cross sections. The high sensitivity demonstrated was relevant for sensing applications of single molecules. We have investigated experimentally the SERS effect on rhodamine 6G molecules, adsorbed on triangular silver particles and photonic metallo-dielectric structures based on polymers. These structures were fabricated by evaporation of a thin metallic film on colloidal crystals followed by casting in PDMS and epoxy resin. In the later, the polystyrene spheres were removed by sonication in organic solvents. The remaining structure allows molecules to be adsorbed at its metallic surface, on top of the triangular particles or inside the spherical holes. The SERS spectra were measured by a scanning confocal Raman microscope. The location of the SERS active centers (hot spots) in arrays of triangular particles (corners and edges) is correlated with the optical near-field enhancements obtained by numerical simulations. In metallo-dielectric photonic structures made of PDMS the Raman images show regions of stable SERS spectra (several pixels wide) and many isolated bright pixels.The isolated pixels are instable in time, i.e. show spectral blinking. The photonic structures we propose can be fabricated in a reproducible way. The field enhancements depend mainly on the size and shape of the arrays, which is not the case for etched silver films and for clusters prepared by colloidal silver. Thus, they are more suitable to investigate the electromagnetic contribution to SERS.

We present simulations of integrated optical devices based on nanometer-thin metallic stripes or wires suitable for guiding long-range surface plasmon polaritons at telecom wavelengths. Propagation of light in these circuits can be directly controlled by using the metal wires simultaneously as waveguides and heating elements. We will show examples of how resistive heating of metallic waveguides can be used to control confinement or used to affect selected parts of multi-mode waveguides in order to realize modulation, attenuation and/or switching.

At optical wavelengths, a chiral sculptured thin film (CSTF) may be viewed as a unidirectionally nonhomogeneous continuum that locally possesses orthorhombic symmetry and globally is structurally chiral. The circular Bragg phenomenon exhibited by CSTFs (i.e., a structurally right/left-handed CSTF of sufficient thickness almost completely reflects right/left-circularly polarized light which is normally incident, but left/right-circularly polarized light is reflected very little, within a specific wavelength regime) has been exploited in circular polarization and spectral-hole filters, among other CSTF applications. The multiscale porosity of CSTFs, combined with their polarization-dependent electromagnetic properties, makes them highly promising platforms for optical sensing and light source applications. After developing a theory based on a spectral Green function for light emission from a point-dipole source embedded in a metal-capped CSTF, we found that the intensity and polarization of the emitted light are strongly influenced by the structural handedness of the CSTF as well as the placement and orientation of the source dipole. The emission patterns across both pupils of the dipole-containing CSTF can be explained in terms of the circular Bragg phenomenon exhibited by CSTFs when illuminated by normally as well as obliquely incident plane waves. Much less radiation is emitted through the metal-capped CSTF surface as compared with the non-metal-capped surface. The emission characteristics augur well for the future of CSTFs as optical biosensors as well as light emitters with controlled circular polarization and bandwidth.

We demonstrate and compare three different experimental techniques to characterize the quality of periodically poled crystals. All techniques are based on the observation and analysis of Maker fringes in either spontaneous parametric down-conversion (SPDC) or second harmonic generation (SHG). For perfectly-poled crystals these Maker fringes are expected to have a sinc²-shape. We show how the observed deviations from this ideal shape can be used to characterize the quality of the poling structure and analyze them with a new Fourier method, which distinguished between variations in the poling composition and poling period.

We have excited a passive LiNbO₃ whispering gallery resonator with an external mode-locked laser. This leads to a phase-coherent excitation of several modes of the resonator. The repetition rate is tuned to an integer submultiple 1/N of the free spectral range of the resonator. The output rate of the resonator is equal to the input rate multiplied by N, showing frequency multiplier functionality. Impact of nonlinearity and of dispersion is minimized by low power level and limited bandwidth of pulses. We show that pulsed ringdown can be measured by modulating the input pulsed train. Quality factor is measured both from CW transmission and from the pulsed ringdown.

Applications for photonic integrated circuit technologies based on the conditional Faraday Effect with electron spins in quantum dots are discussed. The interaction of light with the quantum confined electrons leads to a rotation of the light polarization. Design considerations for polarization multiplexing systems and plasmon resonance sensors based on polarization rotation are presented. Calculations for light of wavelengths λ=1.3 μm and λ=1.55 μm show devices with active regions of a few hundred microns are possible using InAs/GaAs quantum dots. The advantages of spin-based devices are also discussed.

The perturbation theory (PT) for electromagnetic eigenwaves in finite-finite 2D metamaterials is developed. A simple procedure to find the essential part of full solution for electromagnetic field 2D photonic crystals (PhCr) is proposed. The existance of PT small parameter for electromagnetic modes in finite 2D PhCr is proven if sizes are sufficiently big. The spectrum and amplitude distribution for several types of 2D states: band, waveguide, surface and pure local states are considered for PhCr binary samples counting several hudred elementary cells in both directions. Ways of controlled field redistribution inside the structure are analyzed for glass, silicon and silicon-glass 2D PhCr.

The mutual non-orthogonal orientations of its horizontal and vertical bars make T-shaped gold nanodimers chiral. Because of the broken symmetry second-harmonic generation from the structure has different efficiencies for left- and right-hand circularly-polarized fundamental light. The chiral signature arises from the coupling between the bars. One would therefore assume that the chiral signature is largest when the gap size is very small, because then the coupling is presumably the strongest. Counter-intuitively, the measurement results show a very small chiral signature for the smallest gap. To explain the results, one needs to consider the distribution of the local field in the unit cell of the structure.

Recent quantum electrodynamical studies on optically induced inter-particle potential energy surfaces have revealed unexpected features of considerable intricacy. The exploitation of these features presents a host of opportunities for the optical fabrication of nanoscale structures, based on the fine control of a variety of attractive and repulsive forces, and the torques that operate on particle pairs. Here we report an extension of these studies, exploring the first detailed potential energy surfaces for a system of three particles irradiated by a polarized laser beam. Such a system is the key prototype for developing generic models of multi-particle complexity. The analysis identifies and characterizes potential points of stability, as well as forces and torques that particles experience as a consequence of the electromagnetic fields, generated by optical perturbations. Promising results are exhibited for the optical fabrication of assemblies of molecules, nanoparticles, microparticles, and colloidal multi-particle arrays. The comprehension of mechanism that is emerging should help determine the fine principles of multi-particle optical assembly.

We propose an original technique which takes profit of Second Harmonic Generation (SHG) effects in molecular solutions. Our technique exploits the specificities of molecular contributions. We show that we can use the electric field present inside a Scanning Tunneling Microscope (STM) junction towards creating a local non-centrosymmetry via molecular orientation under the tip. Experiments were performed inside a STM junction immersed in concentrated solutions of azo-dyes molecules chosen for their highly nonlinear properties and the possibility to generate a local SHG signal from those molecules was demonstrated. More particularly, the quadratic dependence of the SHG signal intensity with the voltage applied between the tip and the substrate unambiguously shows that it comes from an electric field induced molecular polarization under the tip. The dependence of the signal with the tip height or size is reported and discussed. This approach opens the way to a new and original near field optical microscopy technique.

The electronic transfer of energy from a donor particle to an acceptor is a mechanism that plays a key role in a wide range of optical and photophysical phenomena. The ability to exert control on this transfer is of immense importance. It now emerges that there are all-optical routes which can be introduced to achieve this very purpose. We demonstrate the possibility of promoting energy transfer, in the optical near field, that is rigorously forbidden (on geometric or symmetric grounds) in the absence of laser light. The effect operates through coupled stimulated Raman scattering by the donor-acceptor pair. The absorption of a photon takes place at one particle and stimulated emission at either, coupled with energy transfer between the pair. At this fundamental level, transfer phenomena arise for both single and dual input auxiliary beams. In the latter case the emitted photon may differ from the absorbed photon. In either situation energy transfer will not occur in the absence of auxiliary radiation, if either the donor or acceptor transition is single-quantum forbidden. By engaging input laser light, energy transfer may proceed through two or three quantum allowed transitions. The results for this novel type of optical control suggest transfer efficiency levels comparable to Förster transfer. Many applications are envisaged, chief of which is the potential for all-optical switching.

In our study, the distribution of the near-field close to the chip surface of Photonic Crystal (PhC)-patterned GaN-based blue LED is measured with Near-field Scanning Optical Microscopy (NSOM). The blue LED has the layer structure consisted of Sapphire substrate - n-GaN - Multi Quantum Well (MQW) - p-GaN - ITO, where the PhC pattern is incorporated onto the top p-GaN layer. When the current is applied to the MQW, the light is emitted out of LED and the near-field on the surface of LED chip is picked up by the fiber probe of NSOM system. The system was made by ourselves, and the distance between the probe and the surface is controlled by shear force feedback control method using tuning fork, where lock-in amplifier was used for noise reduction and for dithering the probe.

We investigate experimentally and numerically the efficiency of surface plasmon polariton excitation by a focused laser beam using gold ridges. The dependence of the efficiency on geometrical parameters of ridges and wavelength dependence are examined. The experimental measurements accomplished using leakage radiation microscopy. The numerical simulations are based on Green's tensor approach.

Metallic nanoparticles are a very attractive and fascinating material due to their multifunctional properties, such as surface plasmon resonance absorption and excitation band tuning. In particular, these properties are proved to be valuable in photothermal therapeutic applications, where the tunable, efficient near-field enhanced ablation or photothermal energy conversions can be used to destroy cancerous cells. A similar mechanism can be applied for three-dimensional multilayer nanopatterning of polymer matrix doped with NPs, where the field enhancement and photothermal energy conversion are utilised to produce micro-explosions and voids. Previously, it was reported that engineering the morphology of nanoparticles (rod and shell shape) can greatly enhance the field enhancement and photothermal conditions. Here, we numerically study the field enhancement efficiencies of nanparticles with heterogeneous morphologies (such as metal - dielectric - metal core-shell structures), and compare their efficiencies to conventional nanosphere and nanoshell structures. Unlike the previous approximate analytical models, the SPR excitation and field enhancement efficiencies are numerically simulated, using the frequency-dependent finite-difference time domain method under tightly focused ultrashort pulse laser irradiation to accurately emulate the experimental conditions.

The excitation of surface plasmon-polariton (SPP) waveguide modes in 500-nm-wide and 550-nm-high dielectric ridges deposited on a thin gold film is characterized at telecommunication wavelengths, by application of a scanning near-field optical microscope (SNOM), and by utilizing the finite element method (FEM). Different tapering structures for coupling in SPPs, excited at the bare gold-air interface, are investigated with a SNOM, and the dependence of in coupling efficiency on tapering length is characterized by means of FEM calculations. The performance of this in coupling method is compared to an alternative excitation scheme, where the effective index of SPPs in the tapering region is matched to the index of the incident beam, thereby exciting SPPs directly in the dielectric tapering structure. Single-mode guiding and strong lateral mode confinement of dielectric-loaded SPP waveguide (DLSPPW) modes are demonstrated by characterizing a straight DLSPPW section with a SNOM and with the effective index method (EIM). The propagation loss of DLSPPW modes is characterized for different wavelengths in the telecommunication region, by application of a SNOM, and the results are compared to EIM calculations.

Surface plasmon based photonic devices are promising candidates for highly integrated optics. An important effort in the development of these devices is dedicated to the design of systems allowing the two dimensional control of surface plasmon (SPP) propagation. Recently, it has been shown that Bragg mirrors consisting of gratings of metallic lines or indentations on a metallic surface are very efficient tools to perform this task. Alternatively, using structured dielectric layers on top of the metallic layer to build SPP optical elements based on the effective refractive index contrast has been lately demonstrated. This kind of elements relies on the same principles as conventional optical elements. Here we analyze the ability of gratings of dielectric ridges deposited on a metallic layer to act as dielectric SPP Bragg mirrors. The dispersion relation of these systems shows the presence of a gap whose position can be approximately predicted by the same relation as for standard optical Bragg mirrors. The properties of these dielectric based SPP Bragg mirrors have been examined as a function of several structural grating parameters. The obtained results have been experimentally confirmed by means of Fourier plane leakage radiation microscopy.

We study the integration of plasmonic traps with microfluidic channels. Plasmonic traps are optical traps that use the evanescent field generated by metallic nanostructures at their plasmon resonance to trap small objects. Contrary to conventional - far-field - traps, plasmonic traps do not require complex optics, as the trapping potential is solely determined by the near-field generated by the nanostructure. This work includes the theoretical study of the trapping potential and its relation to the plasmon resonance; the fabrication of plasmonic traps using electron-beam lithography; the integration with PDMS microchannels; and the statistical analysis of small objects trapped in the structure.

Since its inception, the nanotechnology working group at the European Patent Office has been constantly updating the content of its different nanotechnology classification tags which it applies to patent publications worldwide. The main technologies in the nanophotonics area are photonic crystals, surface plasmon devices, semiconductor superlattices and scanning near-field microscopy. Some patent statistics are shown and a brief summary of legal issues is given.

Apertures with diameters below the wavelength of light represent a nanoscale structure with interesting novel properties. They are usually discussed in an array setting leading to integral optical (spectroscopic) effects. We present here results obtained by a combination of such apertures (but investigated as an individual structure) with metal nanoparticles. These nanoparticles are known to exhibit surface plasmon resonance. The optical effect resulting from the combination of both structures were studied by a complementary ultra structural (AFM, SEM) and spectroscopic characterization on the single aperture level, yielding insights into this promising novel nanophotonic element.

When perforated metal films are sufficiently thin, in addition to exciting surface plasmon-polariton (SPP) modes by conventional two dimensional grating scattering, there is also the possibility of coupling to the localised modes associated with the holes. Here, experimental transmission spectra are obtained from focused ion beam fabricated hole arrays exhibiting localized modes in the visible frequency region. We employ both analytical and numerical (finite element) modeling to understand the fundamental properties of the localized mode. Finally, the sensitivity of the optical response to changes in refractive index is explored, and its potential for sensing applications is discussed.

Optical microcavities offer the ability to create extremely low-threshold lasers with high modulation bandwidth. In such microcavity devices, the fraction β of spontaneous emission into the lasing mode can become close to one and the step-like "threshold" gradually disappears. To implement such high-β devices, one can exploit Cavity Quantum ElectroDynamics effects, more precisely spontaneous emission enhancement. The concomitant effect of spontaneous emission acceleration is the preferential funnelling of spontaneous emission into the cavity mode. In our work, the cavity is a double- heterostructure cavity etched on a suspended membrane and contains InAs quantum dots. Lasing is achieved with β-factors higher than 0.44 and is sustained by less than 10 quantum dots.

The nonperturbative theory of the cooperative spontaneous emission from a two level atom trapped in one-dimentional damped nanocavity with a single resonance mode is presented. The time-dependent spectral properties and nonlinear dynamics of a separate photon emission by the micro-molecular-like system "excited atom coupled to a resonance decaying mode" have been analyzed. The investigation has been carried out by solving the Schrödinger equation in the interaction picture with the help of the Green functions method in the Heitler-Ma's form. The formalism was supplemented with the novel algorithm in operating causal singular functions and with fundamentals of the theory of quasi-stationary systems. The proposed theory accounts automatically of both reabsorptions of emitted photon and its simultaneous escaping out of the cavity. Solutions of the wave equation were found without using intermediate virtual states and series expansions. In accordance with the theory of quasi-stationary systems the field of mode decaying exponentially in the empty nanocavity was represented with the Lorenz-shaped packet of stationary photonic states (quasi-modes). The electro-dipolar interaction between the atom and the mode field was adopted to be switched on suddenly. The expressions and plots of emission probabilities spectral densities together with photon emission probability dynamics as functions of time for various ratios Γ/4g of photon escaping rate Γ and coupling constant g are presented. For Γ/4g <1 the transient emission spectrum reveals the presence of two symmetrical side-bands and of the central peak, the latter decaying in time at the rate ∝ Γ/2 so that the final spectrum is a doublet. In this case the photon emission probability is described by decaying oscillations. On the contrary for Γ/4g ≥ 1 the spectrum is a singlet and the emission occurs in exponentially decaying ways.

Optical near-field and far-field for coupled plasmonic nanosystems are investigated. Gap plasmon-polaritons are observed and analyzed with Spectral Boundary Integral Equation based approach. The results indicate pronounced dependence of the field characteristics on the gap size, the particle shape, the orientation and material properties. The gap optimization process is performed and the configurations which provide powerful enhancement of the field amplitude inside the gaps are found. The meshfree procedures of numerical simulation algorithm allow essential flexibility of gap optimization process in comparison with classical boundary element and finite element based tools. Due to fast convergence of solution numerical algorithm provides superior accuracy to deal with extremely high field gradients. In addition reduced complexity and calculation time are guaranteed due to extensive use of Fast Fourier Transforms.

Highly ordered periodic arrays of silver nanoparticles have been fabricated which exhibit surface plasmon resonances in the visible spectrum. We demonstrate the ability of these structures to alter the fluorescence properties of vicinal dye molecules by providing an additional radiative decay channel. Using fluorescence lifetime imaging microscopy, we have created high resolution spatial maps of the molecular lifetime components; these show an order of magnitude increase in decay rate from a localized volume around the nanoparticles, resulting in a commensurate enhancement in the fluorescence emission intensity. Spatial maps of the Raman scattering signal from molecules on the nanoparticles shows an enhancement of more than 5 orders of magnitude.

Yttrium vanadate particles doped with europium are studied for their applications as biomolecule labels. Two parts of our work will be presented. The first concerns the thermal treatment of particles incorporated in a silica matrix. After annealing at 1000°C and redispersion in water by dissolution of the silica matrix, the structural and optical properties are greatly improved: without any modification of size, the obtained nanoparticles appear as perfect single crystals of 33 nm and have the same emission properties as the bulk material, with a quantum yield and emission lifetime increasing up to 40% and 0.8 ms. The second aspect concerns the detection of single nanoparticles and their emission properties as compared to an ensemble of nanoparticles.

The possibility to use periodically poled lithium niobate structures for dielectrophoretic trapping of dielectric particles was investigated. The trapping effect was achieved through the development of opposite electrical charges on z+ and z- faces of a crystal when subject to temperature variation. Appropriate oil suspensions of dielectric particles were used for the experiments which show the possibility to trap those particles by means of the pyroelectric effect in correspondence of the reversed ferroelectric domain areas. Results are presented while perspectives of exploitation in different fields are illustrated.

We present an efficient computational methodology for full electrodynamic calculations of metallodielectric nanostructures based on a multiple-scattering formulation of Maxwell's equations. The method, originally developed for systems of spherical particles (MULTEM code), is extended to systems of particles of arbitrary shape and applied to ordered structures of metallic nanodisks with an aspect ratio as large as five. We first discuss the particle plasmon resonances of single metallic nanocylinders of different aspect ratios. Then, we study the plasmonic excitations of square arrays of metal-dielectric-metal nanosandwiches and the optical response of a rectangular lattice of metallic nanodisks on a dielectric waveguide. Finally we analyse the photonic band structure of a simple cubic crystal of metallic nanodisks.

We present a new photonic micro-optical device based on an array of electrodes made from vertically aligned multiwall carbon nanotubes used to address a liquid crystal cell. The electrodes create a Gaussian electric field profile which is used to reorient a planar aligned nematic liquid crystal. The variation in refractive index within the liquid crystal layer acts like a graded index optical element which can be varied by changing the applied electric field to the carbon nanotube. Results are presented from a device fabricated with a 10μm pitch between the micro-optical elements.

Single-walled carbon nanotube (SWNT) dispersions were prepared in N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA), respectively. The nonlinear optical properties of SWNT dispersions were studied by using the Z-scan method. The nonlinear extinction coefficients increase significantly with increasing SWNT concentration. In the three dispersions, the DMF dispersions show the strongest nonlinear extinction effect. In conjunction with this, the optical limiting performance is also superior for the DMF dispersions. Compared with DMF and DMA, NMP has a much better debundling effect for SWNTs, however the optical limiting properties of the NMP dispersions is inferior. The static light scattering experiment revealed that the DMF dispersions have the largest average bundle size. The principal mechanism of the optical limiting effect of the SWNT dispersions is due to the solvent and/or carbon vapour bubble-induced nonlinear scattering. The present results indicate that the average bundle size of SWNTs in combination with the thermodynamical properties of the solvent, dominate the nonlinear extinction and optical limiting properties of SWNT dispersions.

SHG spectra from silicon films with different average size of nanocrystals were studied as possible material for active channel in nonlinear optical switches. It is seen the spectral peak with energy 3.26 eV is related to defects appeared in interface area silicon-silicon dioxide. For films with small silicon crystals (less than 20 nm) the nonlinear optical response contains two spectral peaks. The second peak is caused by optical response from nanocrystal grain boundary that contains oxygen atoms incorporated in silicon as dipoles inside film. The optical nonlinear switch device based on the nonlinear optical response of SiO_x media inside film was proposed. Also, the silicon film with quartz micro-clusters was investigated as material for making the nonlinear optical transmitter device. The PL spectra of films were, also, studied to observe the various silicon and silicon dioxide fractions. The efficiency of transmission of radiation is sufficient.

Solid thin films of CdSe and CdSe/ZnS nanoparticles on different templates have been investigated under influence of power visible laser radiation. Composite structures including organic semiconductors and CdSe and CdSe/ZnS nanoparticles films have been fabricated. Luminescent and electron properties of the structures have been investigated. Luminescence quantum yield of these nanocomposite structures is shown to exceed that of the films of organic dyes by two orders of magnitude for CdSe nanoparticles with ZnS shell. As for quantum dots without the shell their luminescence quantum yield appears to fall drastically in the films and even in the matrices of organic semiconductors compared to the solution. The presence of CdSe films in multi-layer structures of polyimides leads to abrupt increase in their conductivity by several orders of magnitude. The prospects of development of photovoltaic elements and light-emitting devices including the films with high concentration of CdSe and CdSe/ZnS quantum dots are discussed.

In this paper, we show that a two-dimensional random system can display strong structural colors in transmission. Polystyrene microspheres with a diameter between 0.5 and 1μm have been randomly adsorbed onto a glass substrate. In this size range, light is mainly scattered in the forward direction. Consequently, in-plane multiple scattering can be neglected while spheres are not too close to each others. This allows one to use a single scattering approximation to reproduce transmission spectra of the system. Under appropriate conditions, destructive interferences between incident and scattered light can cause a full extinction in the transmission. In our case, transmission can be as low as 5% at some frequency ranges, generating strong color effects. Additionally, the film color changes with the angle of observation. This angular dependant color is reproduced theoretically taking into account multiple scattering between spheres.

Two and three dimensional structures with micron and submicron resolution have been achieved in commercial resists, polymeric materials and sol-gel materials by several lithographic techniques. In this context, silicon-based sol-gel materials are particularly interesting because of their versatility, chemical and thermal stability, amount of embeddable active compounds. Compared with other micro- and nano-fabrication schemes, the Two Photon Induced Polymerization is unique in its 3D processing capability. The photopolymerization is performed with laser beam in the near-IR region, where samples show less absorption and less scattering, giving rise to a deeper penetration of the light. The use of ultrashort laser pulses allows the starting of nonlinear processes like multiphoton absorption at relatively low average power without thermally damaging the samples. In this work we report results on the photopolymerization process in hybrid organic-inorganic films based photopolymerizable methacrylate-containing Si-nanobuilding blocks. Films, obtained through sol-gel synthesis, are doped with a photo-initiator allowing a radical polymerization of methacrylic groups. The photo-initiator is activated by femtosecond laser source, at different input energies. The development of the unexposed regions is performed with a suitable solvent and the photopolymerized structures are characterized by microscopy techniques.

Giant nonlinear refraction has been experimentally observed in gold island films. The real part of the third-order nonlinear susceptibility χ⁽³⁾(ω;ω,-ω,ω) reaches a value of -8×10^-5 esu (λ = 532 nm, τ = 10 ns) and +5×10^-7 esu (λ = 800 nm, τ = 85 fs). The mechanism of nonlinearity of the refractive index can be associated with the resonance enhancement of the factor of the local optical field at the pump wavelength due to the excitation of surface plasmons, as well as with the contribution of the heating of conduction electrons in an ensemble of metal particles.

The possibility of surface waves amplification by direct electrical current is theoretically investigated in three-layered system with periodical structure at the surface. The analytical calculations were performed in the frame of the Green function method on the base of the concept of effective susceptibility. Numerical analysis clearly proves the presence of convective instability and it means that such a system can be considered as a surface waves' amplifier. Because of periodical structure the phase synchronism domain lies in the range of entirely accessible in practice values of wave vector and frequency. The increment of spatial growth amounts to several tens within the region of phase synchronism. It means that predicted effect of amplification can be applied on practice.

Surface-plasmon-polariton (SPP) resonators consisting of metal strips in free space, and gap plasmon polariton resonators consisting of a metal strip close to either a block of metal or a metal surface, are studied as optical resonators. The analysis is performed using the Green's function surface integral equation method. For strips in free space, we show how the scattering resonances can be understood, by thinking of the strips as optical resonators for short-range SPPs. The two gap resonator configurations, strip-block and strip-surface, have different structure terminations as the width of the strip and the block are identical whereas the surface is infinite. In the strip-surface configuration, the scattering resonances are broader and red-shifted, compared to the strip-block configuration. This is explained as a consequence of the effective length of the resonator being larger in the strip-surface configuration. By varying the gap size, we study the transition from a SPP resonator to a gap plasmon polariton resonator. In the strip-surface configuration, light can be scattered into both out-of-plane propagating waves and into SPPs that propagate along the surface. For small gaps of a few tens of nanometers, a large enhancement in the scattering cross section is seen due to strong scattering into SPPs.

ZnO is a promising material for optoelectronic devices because of its wide bandgap and large exciton binding energy. However, majority of studies of ZnO nanostructures have been focusing on the study of their optical and structural properties. For device applications of ZnO, other factors besides ZnO material quality also play a significant role. For example, a typical ZnO nanorod based light emitting diode (LED) contains a polymer insulating layer and a top contact. The device performance is dependent on the insulating layer and top contact quality. In this work, the effect of different insulating polymers on the performance of p-GaN/n-ZnO LED was investigated. The structure of LED was: Au/ Ni/p-GaN/ZnO nanorods/insulating polymers/Ag. The ZnO nanorods were fabricated by hydrothermal method, and the length of the nanorods was 250 nm. In this work, we investigated absorption spectra, electroluminescence (EL) properties, and I-V curves to characterize the performance of the devices fabricated using spin-on glass (SOG), poly(vinylalcohol) (PVA), polymethyl methacrylate (PMMA) and polystyrene (PS) as insulating layers. Finally, the comparison of the performance of the devices with different polymers was discussed.

We prepared copper-carbon nanocomposite films by co-deposition of RF-Sputtering and RF-PECVD methods at room temperature. These films contain different copper concentration and different size of copper nanoparticles. The copper content of these films was obtained from Rutherford Back Scattering (RBS) analyze. We studied electrical resistivity of samples versus copper content. A metal-nonmetal transition was observed by decreasing of copper content in these films. The electrical conductivity of dielectric and metallic samples was explained by tunneling and percolation models respectively. In the percolation threshold conduction results from two mechanisms: percolation and tunneling. In the early stage of nonmetal-metal transition a reverse effect of metallic to nonmetallic state occurs by increasing metal content. We also study the effect of percolation on Surface Plasmon Resonance (SPR) peak of Cu nanoparticles in visible spectra. The width of this peak is raised by increasing number of percolated nanoparticles. Also position of this peak is shifted to the larger wavelength by decreasing resistivity of film. Mie theory was used for the dielectric sample. Using Mie theory, the size of copper core and copper oxide shell, the dielectric constant of shell and carbon host are estimated from SPR peak. The activation tunneling energy that was obtained from estimated value of Mie theory is consistent with that one obtained from temperature dependence of electrical resistivity. Atomic Force Microscopy (AFM) image shows particle size and coalescence of the nanoparticles.

Forming structures similar to or smaller than the optical wavelength offers a wide range of possibilities to modify the optical properties of materials. Tunable optical nanostructures can be applied as materials for surface-enhanced spectroscopy, optical filters, plasmonic devices, and sensors. In this work we present experimental results on technology and properties of periodical, polymer based optical structures modified by ordered adsorption of silver nanoparticles. These structures were formed combining UV hardening and dip coating from colloidal solutions. We have investigated the influence of silver nanoparticles assembly on the ambient conditions (deposition temperature and time) and surface features (periodicities and shape) of the template micro structures. Optical absorbance as well as morphology of the structures containing silver nanoparticles were investigated by UV-VIS spectroscopy, AFM, SEM and optical microscopy. The influence of silver nanoparticles on the optical properties of the structures was investigated by polarized light spectroscopy (Grating Light Reflection Spectroscopy - GLRS). From the results of this study we propose a low cost procedure for fabricating structures that could be potentially new type of plasmonic sensors exploiting surface enhanced plasmon resonance in silver nano structures.

The combination of microfluidics and optical manipulation offers new possibilities for particle handling and sorting on a single-cell level in the field of biophotonics. We present particle manipulation in microfluidics based on vertical-cavity surface-emitting lasers (VCSELs) which constitute a new low-cost, high beam quality nanostructured laser source for optical trapping, additionally allowing easy formation of small-sized, two-dimensional laser arrays. Single devices as well as densely packed linear VCSEL arrays with a pitch of only 24 μm are fabricated. Microfluidic channels with widths of 50 to 150 μm forming T- and Y-junctions are made of PDMS using common soft-lithography. With a single laser, selected polystyrene particles are trapped in the inlet channel and transferred to the desired outlet branch by moving the chip relatively to the optical trap. In a second approach, a tilted, linear laser array is introduced into the setup, effectively forming an optical lattice. While passing the continuously operating tweezers array, particles are not fully trapped, but deflected by each single laser beam. Therefore, non-mechanical particle separation in microfluidics is achieved. We also show the route to ultra-miniaturization of the system avoiding any external optics. Simulations of an integrated particle deflection and sorting scheme as well as first fabrication steps for the integrated optical trap are presented.

The Eu³⁺-doped Y₂O₃-particles of size 3.5 μm were coated with a layer of indium tin oxide precursor (ITO) and cured at 120oC. The coating process was repeated four times. Finally, samples were annealed at 700 °C to form a cubic structure of ITO. The morphology and structure of obtained ITO- Eu:Y₂O₃ core-shells materials were determined by the X-ray diffraction (XRD), transmission electro-microscopy (TEM) and scanning electron-microscopy (SEM) analyses. In order to comparison of emissive properties, obtained was mixed with micrograins of ZnS:Ag in the same mass ratio. The photo- and cathodoluminescent spectra of obtained structures materials were determined and analyzed. The possible applications are discussed.

Azo-polymers have been the subject of a growing interest since the first demonstration of reversible birefringence and dichroism effects induced optically at room temperature in such materials. It is well established that the mechanisms involved are related to a molecular reorientation following photo induced trans-cis-trans isomerization of the chromophores. The interest for such materials has been strengthened with the more recent demonstration that the photo-isomerization mechanisms can be employed to induce controlled topographic modifications. A simple example is the induction of a sinusoidal modulation of the film surface by the irradiation with an interference pattern between two laser beams. Such a simple step technique appears thus as a simple tool towards realisation of photonic devices. However, if the realisation of gratings with periods in the visible wavelength scale is widely investigated, a strong decrease of the patterning efficiency is observed in the case of periods below 400nm, limiting then the potential of the technique. In order to circumvent this problem we have developed a new azo-polymer presenting an absorption band shifted to the Ultra Violet (UV) region of the spectrum. The possibility to induce gratings with periods down to 200nm with UV irradiation is evidenced. Optical geometries of excitation have been implemented to optimise the modulation efficiencies. As a potential application of the material investigated, the realisation of a polymer micro laser based on a distributed feedback scheme is demonstrated.