This PDF file contains the front matter associated with SPIE Proceedings Volume 11332, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

Along with increasing demands and rapid development of nanotechnology in various fields, the combination of photonics, nano-optics, biology and chemistry opens new opportunities of developing optical sensors with subwavelength elements or micrometric structures. An innovative sensing mechanism based on the variations in the sensor radiation diagram in correspondence of changes in the refractive index of the surrounding material is illustrated. Particularly, we present a theoretical investigation of two different prototypes of dielectric structures for sensitive and compact chemical optical sensing through the radiation pattern.

In this paper, a complete characterization of the dielectric parameters of thin anodic Al₂O₃ membranes with formed nano-scale air-filled pores was performed in the frequency range 0-40 GHz by a combination of two microwave methods - a resonance method applying pair of cylindrical resonators that support excited modes with mutually perpendicular electric fields and allow evaluation of the dielectric anisotropy, and a broadband method, where planar samples cover the top surface of different transmission lines (coplanar waveguide and microstrip line). It was found that the purity of the initial aluminum foil as well as the thickness of the obtained dielectric membranes influence their optical (perpendicular transmittance through the membranes) and dielectric properties (dielectric constant and dielectric loss tangent). The main benefit of these investigations is the established dielectric anisotropy of the test samples (different dielectric parameters in parallel and perpendicular directions to the sample surface), which confirms the metamaterial-like character of anodic aluminium oxide (AAO). Three types of AAO samples' behaviour were observed due to the realized purity: 1) relatively pure dielectrics with equivalent dielectric constant ~5-7 and less; 2) lossy dielectrics with contaminations (~7-10) and 3) poor dielectrics with increased conductivity due to the metal inclusions (equivalent dielectric constant above 10 and equivalent conductivity 0.25-50 S/m). The applied microwave methods allow us to optimize the used technology for manufacturing acceptable metasamples with high final purity, suitable for optical applications.

In the last decades, great body of interest is given to the design of polymer nanocomposites with carbon nanotubes, since such materials possess great potential for various applications. The present report deals with kinetics of phase formation of nanocomposite consisting of thermotropic polymer liquid crystalline poly(heptane-1,7-dyil-biphenyl-4,4’- dicarboxilate), P7MB, and 1 wt. % single wall carbon nanotubes. Excellent dispersion of nanotubes, proven by scanning electron microcopy, was achieved. It was due to separate ultrasonication of both constituents in solvent and consequent mixing. This approach resulted in excellent non-covalent bonding and formation of nanofibers with a diameter of about 150 nm. Investigation on kinetics of structural formation at different iso- and non-isothermal conditions was performed by means of differential scanning calorimetry. The results showed that cooling down the isotropic melt state, a smectic phase transition takes place in a very short time for both – neat P7MB and the nanocomposite. At lower temperatures, there is a partial crystallization. The smetic phase formation happens in identical way in all cases. However, there is a considerable difference in the way of crystalline phase formation, originating from the special restrictions, introduced by the nanotubes. Non-isothermal phase kinetics was followed by modified Avrami, Ozawa, Liu and Mo approaches.

Efficient preparation of dispersions of platinum nanoparticles was achieved by reduction of chloroplatinate ions (PtCl₆^2-) by hexadecylaniline (HDA) as the reaction occurred at the air/water interface where the insoluble monolayer of HDA was spread. The obtaining of the platinum nanoparticles, formed spontaneously at the air–water interface by HDA enables their facile transfer as multilayers onto suitable solid supports by means of the Langmuir-Blodgett technique. Langmuir-Blodgett films were characterized by Atomic force microscopy (AFM) imaging and X-ray photoemission spectroscopy (XPS).

In the course of our studies on the synthesis of porous metals by de-alloying of amorphous precursors the present work was devoted to the influence of alloy composition and conditions of selective dissolution of palladium based glasses on the microstructure of the final porous material. More pronounced three-dimensional ligament structure was found at the chemically de-alloyed glasses compared to those treated electrochemically. Noticeable difference in the size of the pores and ligaments between chemically and electrochemically partially dissolved Pd₃₀Ni₅₀Si₂₀ glasses compared to Pd₄₀Ni₄₀Si₂₀ was also observed. Superior catalytic activity towards oxidation of ethanol of the porous metal prepared by de-alloying Pd₃₀Ni₅₀Si₂₀ compared to that of the de-alloyed Pd₄₀Ni₄₀Si₂₀ was established.

An optical sensor for sensitive and selective detection of iron(III) has been developed based on redox interaction of Fe(III) ions with starch-coated silver nanoparticles (Ag-NPs) in the presence of 0.001 mol/L HCl. Starch-coated Ag-NPs with an average diameter of 15.4±3.9 nm were successfully synthesized through a simple green method using D-glucose as reducing agent and soluble starch as protecting polymer. The synthesized silver nanoparticles showed a strong localized surface plasmon resonance (LSPR) band around 408 nm and linearly decreasing intensity of LSPR band with increasing concentration of Fe(III) in hydrochloric acid aqueous solution (pH ⁓3). Based on the linear relationship between LSPR intensity and concentration of Fe³⁺ ions, the as-synthesized starch-coated silver nanoparticles could be used as a smart optical probe for sensitive and selective detection of Fe³⁺ ions in water with a linear range from 0.7 to 7 mg/L Fe³⁺ and detection limit of 0.1 mg/L; the relative standard deviation values varied between 2 and 6 % for the whole calibration range. Experiments performed demonstrated that the metal ions Na⁺, K⁺, Mg²⁺, Ca²⁺, Pb²⁺, Cu²⁺, Zn²⁺ , Cd²⁺, Hg²⁺, Co²⁺, Ni²⁺, and Fe²⁺ do not interfere, due to the absence of oxidative activity of these ions, which guarantees the high selectivity of the proposed optical sensor toward Fe³⁺ ions in aqueous samples. On the basis of experimental results, a detection mechanism of oxidation–reduction reaction between Ag-NPs and Fe³⁺ ions was proposed. Moreover, the starch-coated Ag-NPs could be applied to the iron speciation in ground and tap waters.

We investigated laser beam reflection by optically-transparent hydrocarbon polymeric material subjected to low-energy ion implantation. In our study were measured 5 mm-thick plates of polymethylmethacrylate (PMMA) implanted with silicon ions (Si⁺) accelerated to a relatively low energy of 50 keV at Si⁺ fluence of 10¹⁶ ions/cm². Due to ion-produced destruction of the polymer network and reorganization of the organic structure in a depth of PMMA plate, a buried ion-modified layer with ~ 80 nm thickness is formed within the PMMA. The material in this ultra-thin nano-sized layer beneath the top surface of PMMA (in a depth of ~ 100 nm) is organized in carbon nanoclusters with a mean size of about 2 - 3 nm. The nonlinear gradual in-depth distribution of the complex refractive index in the nanostructured region of the polymer results in a significant modification of the reflection of coherent light by the formed structure. Also, the reflected beam undergoes a strong laser-induced photothermal interface lensing upon irradiation by CW laser ( λ= 532 nm) with an optical power above 30 mW. The presence of thermo-lenses can limit the optical and photonic applications of transparent ion-implanted polymers. Here, this negative effect is studied as dependent on both incident laser power and incidence angle of the laser beam.

Forced droplet oscillations are used as a tool for study or manipulating the droplet behavior and as well the properties of the liquid-gas interface¹. Resonant droplet tensiometry (RDT) is an experimental technique that uses a frequency modulated dielectrophoretic force to excite axisymmetric resonant oscillations in supported liquid droplets. Depends on the force amplitude and geometry of the electric field applied, RDT is capable to generate surface capillary waves only or to drive the entire bulk of the liquid droplet². Constrained droplet eigenfrequency strongly depends on the contact-line properties and thus determines the resonant frequency. This work is dedicated to our study of weak capillary oscillations of supported spherical droplets with fixed (static, anchored) contact-line. Our recent experiments with pendant microdroplets show a strong correlation between the theoretically calculated eigenfrequency³ and our RDT experimental results⁴. This led us to propose the idea for the eigenfrequency approach in the nanodroplets research. We also analyze the future application of surface plasmon resonance, caused by capillary waves of oscillating nanodroplet⁵, as a possible solution for nanodroplet resonant frequency detection in RDT.

The objective of this research was to develop a quantitative assay for analysis of electrolytes (Na, K, Ca, Mg) in blood serum by use of simple procedure and single pulse Laser-Induced Breakdown Spectroscopy (LIBS). Serum samples were homogenized and encapsulated in a polyacrylamide gel drop during gel formation and fixed on a silicon (polysiloxan) glue coated glass planch, with two internal standards for signal normalization, better reproducibility and accuracy: Rb was chosen for alkali metals and Ba for alkali earth metals signal correction. Water was gently evaporated on a hot plate at 80oC together with gel formation and fixation, and the resulting gel film, containing the sample, analysed by repeatedly shooting the laser on its surface and accumulating spectra. No additional sample preparation was necessary with 5 to 20 μl of Serum consumption. Limits of detection of 6, 0.6, 1.9 and 1.7 μg/mL for Na, K, Ca and Mg respectively were obtained with the proposed setup. The resulting linearity for the four elements ranged from 3 times below to 2 times above the expected blood serum concentration levels variation, at less than 10% RSD. Finally, the methodology was assessed in the determination of the metals in real samples of human blood serum and the performance compared to a standard, automated clinical laboratory assay where Ca and Mg are determined by complexometry/colorimetry, and Na and K – electrochemically by use of ion selective electrodes, in a biochemical analyzer assembly.

In the present study a simple and convenient solution route to grow submicron-sized CuO structures onto the surface of g-C₃N₄ was demonstrated and the upgraded visible-light-driven photocatalytic activity of the as-prepared composite was revealed. The buildup of CuO_{(4.4 wt%.)} /g-C₃N₄ p-n heterojunction was successfully accomplished via two-step ammonia- evaporation-induced synthetic approach. The resulting inorganic/organic composite was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, thermogravimetry, ultraviolet-visible diffuse reflectance spectroscopy and photoluminescence spectroscopy to examine its phase structure, valence state, microstructural, thermal and optical properties. Its photocatalytic efficiency was tested using Malachite Green photodegradation in natural seawater and the results indicated that CuO/g-C₃N₄ is much more active than the individual components in the photodegradation of MG. A plausible photocatalytic mechanism was also proposed.

Aerogel granules or micropowders are suitable matrixes for the incorporation of hybrid molecules with promising optical or electrical applications. By using a two-step colloidal preparation scheme red or green emitting complexes, [Eu(phen)₂(NO₃)₃] or [Tb(phen)₂(NO₃)₃] are immobilized in silica aerogel granules, leading to a bright red or green luminescence upon 350 nm excitation. The optical properties of SiO₂:Tb(phen)₂(NO₃)₃ composites are investigated depending on the preparation strategy. The quantum yield of the as prepared hybrid complexes and composites is discussed.

In this study, new As(V)-imprinted polymer (As(V)-IIP) for selective adsorption and separation of As(V) was prepared by synthesis procedure based on 2D imprinting approach. Initially, the polymeric core was synthesized via dispersion polymerization between glycidyl methacrylate as a functional monomer and trimethylolpropane trimethacrylate as a cross-linking agent. Then the ion imprinted layer was formed by grafting of 1-methylimidazole on the surface of the polymeric particles in presence of As(V) as a template ion. The newly synthesized As(V)-IIP was characterized using elemental microanalysis, scanning electron microscopy and nitrogen adsorption–desorption measurements. The effect of the porogen solvents acetonitrile, toluene and methanol on particle shape and morphology was presented. The adsorption properties of As(V)-IIP toward As(V) were studied by batch procedure. The optimal pH range for the quantitative sorption (> 95%) of As(V) was 7-9, and full desorption was achieved by 3 mol/L HCl. The As(V)-IIP possesses high capacity toward As(V) (9.8 μmol/g sorbent) and good mechanical and chemical stability. Experiments performed for selective determination of As(V) in water samples showed that the interfering matrix does not influence the extraction efficiency of As(V)-IIP. Finally, the prepared As(V)-imprinted smart polymer gel was successfully applied to the selective recognition and determination of As(V) ions in water samples.

The rapid development of micro- and nanofabrication technologies during the recent decades allows for constant improvement of electronic devices. Furthermore, it is now possible to couple these devices to mechanical, optical, quantum, bio, and their systems. As these technologies find new applications, the requirements for the materials are becoming higher. Some of these applications (plasmonics, for instance) benefit from materials of high purity and free of defects. Zone-melting is a well-known and refined process for improving the purity and crystallinity of macro objects but on the microscopic scale it has not been studied as thoroughly.

In this work we explore the idea of implementing zone melting on a micrometer scale by localized heating induced by focused electron beam irradiation. The model structure is a thin metallic stripe on a quartz substrate. The peak temperature and the temperature profile around the heated zone are evaluated by finite element simulations. The results show that the molten zone is narrow but when it is at the end of the stripe, the peak temperature increases. This effect was compensated by introducing heatsinks with optimized size. Proof- of-concept experiments were performed on the optimized structures in a scanning electron microscope (SEM) modified for operation with a higher beam current.

The surface plasmon resonance (SPR) is an optical method that allows the study of interactions of biological objects with solid surfaces in real time in situ. In the present study the adsorption of ferritin on gold surface was investigated by using a null ellipsometer. The dependence on the optical parameters of adsorbed protein under normal physiological conditions was obtained. A comparison with another method is made. The experiments performed show that ellipsometry is a reliable and correct method for determining of SPR.

Electrospinning is a nanofiber fabrication technique with various applications in diverse fields. Especially interesting is the possibility of fabricating composite structures containing noble metal nanoparticles, which are known for their excellent plasmonic properties. In this paper we explore the optimal conditions for embedding Ag nanowires (100±40 nm in diameter and 0.5-100 μm in length) in electrospun PVA fibers. The thus fabricated nanofibers are analyzed using optical and scanning electron microscopy and energy dispersive X-ray spectroscopy. This highly symmetric system is very suitable for studying the plasmonic properties of silver nanowires both theoretically and experimentally.

The process of four photon parametric mixing can be used to convert the input laser sources, working in CW and pulse regimes, into light at several different frequencies. An effective parametric energy conversion can be observed when phase matching conditions between the waves are satisfied. The basic theoretical investigations are focused on efficiency of the four-photon mixing and parametric gain with applications such as all-optical signal sampling, time-demultiplexing, pulse generation and wavelength conversion. The parametric amplifiers have capacity to provide high gain and low noise at arbitrary wavelengths with proper fiber design and pump wavelength allocation. The problem with the generation of new frequencies on distances less than one coherent length in the process of parametric four-photon mixing was solved in approximation of fixed electric field of the pump wave. The idea of our research is to solve the more general problem in which it is taken into account the mutual action of the first and second order of dispersion and all real χ(3) nonlinear processes on the parametric four-photon mixing. In CW regime the solutions of the problem, presented above, was solved in the form of Jacobi elliptic functions. In pulse regime we found optimal conditions, where the process of energy exchange is still effective. In this regime a quasi-periodic conversion is observed and group velocity difference between the pump and signal wave is compensated by nonlinear mechanisms.

From long time transverse and longitudinal optical forces are used for non-contact and noninvasive manipulation of small particle. The following question arises: What is the impact of these forces on the continuous media as air and silica. In this work we obtain analytical expressions for radiation force and radiation potential in dipole approximation of laser pulses propagating in dielectric media. The longitudinal force is proportional to the second time derivative of the intensity profile. At fixed initial energy of a laser pulse, as shorter is the pulse as bigger is the force. It is possible the neutral particles in gases and solids to be confined in the pulse envelope and to move with group velocity. In silica the longitudinal force of a femtosecond pulse is of few order of magnitude greater than molecular forces. Thus, the ablation in silica can be realized through broken molecular connections.

Here we will present a reliable (experimentally and numerically proved) technique for multi-spot pattern formation in the focus of a lens (i.e. in the artificial far field). This was done using large square-shaped and/or hexagonal optical vortex (OV) lattices generated by spatial light modulators. Experimental and numerical results showing a controllable far-field beam reshaping when such lattices are generated in the Fourier plane will be discussed. Even more interesting bright structures can be obtained by combining OV lattices (of any type) with different node spacings. We show that the small-scale structure of the observed patterns results from the OV lattice with the larger array node spacing, whereas the large-scale structure stems from the OV lattice with the smaller array node spacing. The orientation of the mixed far-field structures is proven to rotate by 180° when all TCs are inverted.

We theoretically investigate the transformation of a nondiverging Bessel beam with phase singularity n, which is transversally obstructed by a circular aperture, in the process of its diffraction by a fork-shaped grating with integer topological charge (TC) p. Analytical expressions describing the diffracted wave field amplitude and intensity distributions are derived and analyzed. The diffracted beams are nondiverging in a defined propagation interval, which is calculated. The zeroth-diffraction-order beam has TC same as that of the incident beam. However, the TC of the higher- diffraction-order beams can be increased or reduced compared to that of the incident beam, or it can be equal to zero. Also, the expressions for the radii of the central bright spot (if the beam is without TC) and of the vortex core (if the beam is with phase singularity) are derived.