We report on the surface plasmon resonances of mid-infrared Au antennas deposited on an absorbing silicon-rich oxynitride (SRON) thin film, and on their utilization for enhancement of a spatially localized absorption of infrared (IR) radiation in SRON. The antenna resonances were experimentally determined from far-field IR reflection spectra measured over a broad mid-IR range. Due to a hybridization effect caused by the strong coupling of localized surface plasmon resonances with vibration modes, phonon resonances in SRON, these spectra show up the Rabi splitting of the reflection peaks, and thus, three hybrid branches where resonant wavelengths scale nonlinearly with the antenna length have become apparent. To maximize spatially localized plasmon-enhanced energy absorption in SRON, a compromise wavelength between that one related to optimum antenna resonances and the SRON resonant absorption wavelengths must be chosen. We stress that the principles of this method can be utilized in other dielectric or semiconductor materials resonantly absorbing in the mid-IR range, and, more generally, in other spectral regions, including the visible (e.g., due to excitons). Hence, in addition to the spatially localized heating, the principles can be exploited in an optimization of the efficiency of IR and light detectors, solar cells, biosensors, and other applications.

Scanning near-field optical microscopy (SNOM) in combination with interference structures is a powerful tool for imaging and analysis of surface plasmon polaritons (SPPs). However, the correct interpretation of SNOM images requires profound understanding of principles behind their formation. To study fundamental principles of SNOM imaging in detail, we performed spectroscopic measurements by an aperture-type SNOM setup equipped with a supercontinuum laser and a polarizer, which gave us all the degrees of freedom necessary for our investigation. The series of wavelength- and polarization-resolved measurements, together with results of numerical simulations, then allowed us to identify the role of individual near-field components in formation of SNOM images, and to show that the out-of-plane component generally dominates within a broad range of parameters explored in our study. Our results challenge the widespread notion that this component does not couple to the aperture-type SNOM probe and indicate that the issue of SNOM probe sensitivity towards the in-plane and out-of-plane near-field components - one of the most challenging tasks of near field interference SNOM measurements - is not yet fully resolved.

Homogeneous rapid sintering of nanoparticle powder compacts of yttria-stabilized zirconia was achieved by the radiation heat transfer. Green bodies were prepared by cold isostatic pressing (CIP) at various pressures providing different porosity of samples before sintering. Pressure-less sintering was performed in air at a heating rate of 100 °C/min up to the 1500 °C/1 min. Scanning electron microscopy, mercury intrusion porosimetry, and Archimedes technique were used to characterize the microstructure and to determine the density of the green and sintered bodies. Contrary to expectations, our results reveal opposite dependence of the green- and sintered densities on the CIP pressure. Since the whole sintering process does not exceed 10 min, to propose what processes are responsible for observed results, our attention is focused on the radiation heat transfer from furnace heating elements into the ceramics. Our arguments are supported by numerical calculations of the electromagnetic field enhancement in/between particles.

We report on the influence of a nanocrystalline diamond (NCD) thin film or its segments on optical response of gold plasmonic single and dimer antennas in the visible and near‐infrared. We have simulated optical response of these antennas to the electromagnetic radiation in the wavelength range 500–1500 nm. As the response, we take the localized plasmon resonant wavelength and electric field enhancement around the antennas, localized on the top of NCD films or close to NCD segments. Compared to the antennas on a bare glass substrate, the presence of NCD near the antennas causes a significant red‐shift of the antenna resonant wavelength and slightly decreases the antenna resonant scattering cross section. As for the antenna near‐field, it is more enhanced at the antenna–NCD interface than at the antenna–glass one; however, this field is more confined to the interface.

The tailoring of electromagnetic near-field properties is the central task in the field of nanophotonics. In addition to 2D optics for optical nanocircuits, confined and enhanced electric fields are utilized in detection and sensing, photovoltaics, spatially localized spectroscopy (nanoimaging), as well as in nanolithography and nanomanipulation. For practical purposes, it is necessary to develop easy-to-use methods for controlling the electromagnetic near-field distribution. By imaging optical near-fields using a scanning near-field optical microscope, we demonstrate that surface plasmon polaritons propagating from slits along the metal-dielectric interface form tunable interference patterns. We present a simple way how to control the resulting interference patterns both by variation of the angle between two slits and, for a fixed slit geometry, by a proper combination of laser beam polarization and inhomogeneous far-field illumination of the structure. Thus the modulation period of interference patterns has become adjustable and new variable patterns consisting of stripelike and dotlike motifs have been achieved, respectively.

The interaction of a scalar wave (thermal neutrons) with a single Si crystal is treated using Ewald's self-consistent field method. Considering from the very beginning the two-dimensional translation symmetry of the problem, the reflectivities of allowed and forbidden reflections in the Bragg geometry valid for both coplanar and non-coplanar cases are derived. It is shown that there exists a very narrow reflectivity peak of the forbidden reflection as a result of the symmetry breaking due to a crystal surface.

An analytical model of the response of a free-electron gas within the nanorod to the incident electromagnetic wave is developed to investigate the optical antenna problem. Examining longitudinal oscillations of the free-electron gas along the antenna nanorod a simple formula for antenna resonance wavelengths proving a linear scaling is derived. Then the nanorod polarizability and scattered fields are evaluated. Particularly, the near-field amplitudes are expressed in a closed analytical form and the shift between near-field and far-field intensity peaks is deduced.

Deposition and oxidation of metallic gallium droplets on Si(111) were studied by angle resolved X-ray photoelectron spectroscopy. Two gallium peaks - Ga 3d and Ga 2p - were simultaneously measured in order to get an advantage of different inelastic mean free paths of photoelectrons from these two energy levels differing in binding energy by 1100 eV. Together with the angular dependent data it enhances the precision of the size characterization of Ga droplets and oxide thickness determination. A model for the calculation of theoretical intensities based on an ellipsoidal shape of droplets is presented and a simple procedure for estimation of droplet height and actual surface coverage based on measurement on a single emission angle is suggested. (C) 2008 Elsevier B.V. All rights reserved.

This paper deals with the analysis of the influence of humidity on the process of local anodic oxidation carried out by atomic force microscope (AFM) on GaAs (100) surfaces. Recent experiments have shown that the height and half width of oxide nanolines do not increase monotonously with relative humidity, but for lower relative humidities (< 50%) the lines comparable in size to those prepared at 90% were obtained. However, their height and width along the lines revealed significant variations. To better understand these phenomena, the AFM force-distance spectroscopy measurements together with computer simulations of an electric-field distribution and water bridge formation between the tip and the substrate at different relative humidities were carried out. Our experiments on AFM force-distance spectroscopy have not proved an enhanced water condensation between the tip and the surface at lower humidities. However, the simulations of the electric field in the vicinity of the tip at the early stages of the oxidation process at low relative humidities showed an increase in the average intensity in the oxide layer promoting the diffusion of oxidizing species toward the substrate and, hence, the formation of oxide lines under these conditions. Finally, our simulations on water bridge variations along the tip track showed that at lower humidities there are higher relative standard deviations in the size of the water bridge while the tip is being moved along the surface. This indicates why the oxide lines showed a bigger variability in size.

Diffraction on a crystalline slab formed by point-like scattering centres is treated as a multiple scattering problem based on the Ewald equations. Using general results expressed in a lucid matrix form, the two-beam solution for both coplanar and non-coplanar cases valid near and far from Bragg peaks is found and a detailed comparison of the final formulae obtained with those following from Laue's theory is performed.

In Laue's dynamical theory of diffraction, the boundary conditions claim to introduce a mathematical plane instead of the discrete atomic surface of the crystal. This assumption is analysed from the point of view of Ewald's theory based on the microscopic discrete model of a crystal, where no boundary conditions are needed.

The scattering of a scalar plane wave (neutrons) from a single atomic plane consisting of any two-dimensional lattice with a basis is studied using the Ewald dynamical theory of diffraction. Formulae for the reflection and transmission coefficients obtained by evaluating the optical plane lattice sums are valid for general geometries, including nonsymmetrical and noncoplanar diffractions. The approach adopted is different from and more general than that by Yashiro & Takahashi [Acta Cryst. (2000), A56, 1663-167]. The structure factor yielded by this procedure differs from that used in the kinematical or Laue dynamical diffraction theories.

A simple computational model based on the kinematic scattering approach was tested for the ability to determine the surface structure of Ni(1 0 0), Ni(1 0 0)–c(2×2)–Na and Al(1 1 1), and the results were compared with those found by the complex dynamical analysis. Although to describe precisely the surface solid structures, the dynamical theory must be generally applied, the rough treatment of the experimental data by this kinematic method gave us an useful estimation of the structural parameters. Additionally, a detailed statistical analysis of the structural parameters was carried out.

In this paper the basic principles of non-contact scanning force microscopy (SFM) are explained. The major long-range forces acting between a tip and a sample, and consequently the changes of vibration characteristics with the tip–sample distance, are discussed. To estimate the resolution limits of the non-contact method, the motion of a vibrating silicon cantilever above testing silicon nanostructure models was simulated numerically. This was done both in the mode of constant height and of constant force. To simulate the real behaviour of the tip in the mode of constant force, we included into our calculations the feedback loop. It was shown that by using long-range van der Waals forces an atomic lattice periodicity and individual adatoms can be recognized by non-contact SFM only when the equilibrium tip–surface distance is ∼1.0 nm. Copyright © 2000 John Wiley & Sons, Ltd.

The influence of argon ion-beam bombardment of growing Al, Mo and Ti thin films deposited by ion-beam sputtering on their composition and optical properties was studied. The Ar ion energy and ion-to-atom arrival ratio were 100–600 eV and 0.15–1.75 respectively. The concentration of Mo (A1) in the thin films decreased (increased) with ion energy as the Ar content increased (decreased). The Ti content was below 35% for all ion energies. The ratio O/Ti was close to the stoichiometric value of two for all ion energies up to 400 eV. Higher ion-beam energies and doses led to higher values of the index of refraction for Al and Ti thin films. Furthermore, an increase in the energy of the ions caused a decrease in the deposition rates of all films due to resputtering of the thin film atoms and, in the case of Al thin films, intensified the amorphization process in the Al/Si structure.

Using Ewald's self-consistent theory of multiple scattering the reflection of the scalar plane wave on an ideal semi-infinite crystal formed by point-like diffraction centres is studied. Exact many-beam dispersion relation and analytical formulae for the reflectivity deduced in our previous papers are analyzed and brought into new forms apt for application in the short--wavelength region. The obtained expression for the reflectivity is effective for the so-called crystal truncation rod scattering as well as the usual Bragg reflection, including the special cases such as total reflection at grazing incidence, Bragg reflection at the Bragg angle Pi/2, and for both coplanar and noncoplanar reflections.

The reflection of a de Broglie plane wave incident on a system of point scatterers (nuclei) forming an ideal semi-infinite crystal is studied using the T-matrix formalism of the Ewald dynamical theory of diffraction. Using from the beginning the two-dimensional translational symmetry of the crystal bordered by a surface, simple exact many-beam analytical formulae for the intensities of the reflected waves are deduced, whereby the Ewald sphere is replaced by 'the gamma diagrams' and the usual three-dimensional dispersion surface by a two-dimensional 'dispersion plot'. The results obtained are valid for arbitrary angles of incidence (including the grazing incidence, Bragg angle near pi/2, near or far from the Bragg peaks) and for any directions of the reflected waves (including both the coplanar and the non-coplanar reflections). The transparent algebraic form of the final formulae allows us to discuss analytically the solutions of the dispersion relation and the intensities of the reflections.

Dominant nonlinear electric dipole polarizations at the interaction of fundamental and second harmonic waves in centrosymmetric media without and with memory are treated in this paper. The process of forming a permanent spatially periodic quadratic susceptibility grating in the medium with memory is described from the phenomenological point of view.

The classical theory for the scattering of electromagnetic radiation by a cylinder described by a local dielectric response function is extended to the case of a cylinder with spatial dispersion where two transverse exciton-polariton waves and one longitudinal one are excited. The normal-incidence extinction width spectra of the cylinder in the region of an isolated exciton transition are calculated using Pekar's additional boundary conditions. It is found that the spatial dispersion results in pronounced shifts of the main peaks in these spectra.