D. A. Kurdyukov

Nonlinear diffraction and second-harmonic generation enhancement in silicon-opal photonic crystals

Nonlinear diffraction in three-dimensional silicon-filled photonic crystals of opals is studied. Efficient backward second-harmonic generation (SHG) is observed in the specular direction upon the fundamental radiation reflection from the (111) face of the face-centered-cubic opal lattice. Tuning the fundamental wavelength across the photonic band gap (PBG) results in the 20-times increase of the second-harmonic intensity. The SHG peak has the width of approximately 20nm and is located at the long-wavelength edge of the PBG.

Subpicosecond shifting of the photonic band gap in a three-dimensional photonic crystal

We demonstrate spectral shifting of the photonic band gap in a three-dimensional photonic crystal within a time of less than 350fs. Single 120fs high-power optical pulses are capable to induce the transition from the semiconductor to the metallic phase of VO2 in the pores of our artificial silica opal. The phase transition produces a substantial decrease of the real part of the effective refractive index of the photonic crystal and shifts the spectral position of the photonic band gap.

Three-dimensional ordered silicon-based nanostructures in opal matrix: preparation and photonic properties

Abstract Three-dimensional ordered opal–Si nanocomposites with direct (opal voids are infilled with silicon) and inverted (opal skeleton is removed from the initial composite) structures have been synthesized. The thermal chemical vapor deposition technique is used to incorporate silicon into the voids. An electron microscopy analysis reveals a uniformly thick silicon layer on the inner surface of opal voids. Maxima in the reflection spectra from the (1 1 1) surface of the composites are shown to arise due to the Bragg diffraction of light. These maxima are interpreted as a manifestation of photonic band gap that is tunable in position and width by varying the fill factor of the opal voids.

Synthesis of monodispersed mesoporous spheres of submicron size amorphous silica

A technique has been developed for synthesis of submicron monodispersed mesoporous spheres of amorphous silica from an alcohol-water-ammonia mixture by means of tetraethoxysilane hydrolysis in the presence of hexadecyltrimethylammonium bromide. The mechanism of sphere formation from aggregates of close-packed surfactant cylindrical micelles coated by silica has been proposed. The specific surface area in the synthesized spheres is higher than 800 m2/g, whereas the pore volume and average diameter are equal to 0.63 cm3/g and 3 nm, respectively. The average size of particles is shown to decrease twice after the temperature of the synthesis is increased twice. According to the data of atomic force spectroscopy and dynamic light scattering, the average diameter of mesoporous spheres can be controllably varied in the range 300–1500 nm with a root-mean-square deviation of no more than 6%.

Enhancement of optical and magneto-optical effects in three-dimensional opal/Fe3O4 magnetic photonic crystals

Three-dimensional magnetic photonic crystals, based on an artificial opal matrix with embedded magnetite Fe3O4, were investigated in both transmission and reflection in the near-infrared and visible spectral range. A strong enhancement of the polar Kerr effect and a modification of the Faraday effect have been found near the photonic band gap at about 1.8 eV. Surprisingly the shapes of the loops of magnetic hysteresis measured by magnetic circular dichroism were found to depend on the wavelength of light. This observation has been explained using a model where two types of magnetite particles have different coercive fields.

Effect of tetraethoxysilane pretreatment on synthesis of colloidal particles of amorphous silicon dioxide

The effect of the time passed after tetraethoxysilane treatment with ammonia on the diameter of particles produced by tetraethoxysilane hydrolysis in alcohol-water-ammonia media is studied. The regulation the time passed after of tetraethoxysilane treatment results in the synthesis of submicron monodisperse spherical silica particles with diameters differing by a factor of two. The difference is explained by the formation of SiO2 particles with sizes of 10–100 nm in tetraethoxysilane during 10–30 h after treatment with ammonia. These particles enhance the concentration of nucleation centers in a reaction mixture, thus decreasing the final size of monodisperse silica spheres. Opal films with a high structural perfection and pronounced photonic crystal properties are grown based on the obtained monodisperse SiO2 particles.

Hysteresis of the photonic band gap in VO2 photonic crystal in the semiconductor-metal phase transition

VO2 photonic crystals exhibiting a semiconductor-metal phase transition at 55–75°C have been synthesized by the infiltration of vanadium dioxide (VO2) into opal crystals and the subsequent removal of SiO2 by etching. A study of the optical reflection spectra of such crystals demonstrated that they are characterized by a wide photonic band gap (in the [111] direction of light propagation) in the visible spectral range. The energy position of this band gap changes abruptly upon a phase transition. The temperature shift and hysteresis of the position of the photonic band gap were measured. Quantitative calculations of the reflection spectra of photonic crystals of opal and VO2 were performed in terms of the model of a layered periodic medium, and numerical values of the geometric parameters and optical constants of the studied three-dimensional periodic structures were obtained.

Photonic Crystals with Tunable Band Gap Based on Infilled and Inverted Opal-Silicon Composites

Abstract : Three-dimensional opal-Si composites with both direct (a variable extent of filling of opal voids with Si) and inverted structures have been synthesized. A structural analysis of these fabricated systems is performed. Reflectance spectra from the surface (III) of the composites are measured. Observed spectral features are interpreted as a manifestation of the direction III photonic band gap that is tunable in position and width in the visible and near-infrared spectral ranges.

Three-dimensional array of silicon nanoscale elements in artificial SiO2 opal host

Abstract Regular systems of silicon nanoclusters containing up to 1014 cm−3 elements have been fabricated in a sublattice of voids of artificial opal. Structural studies of samples by transmission electron microscopy (TEM), high resolution electron microscopy (HREM) and Raman measurements were carried out. The regular lattices of Pt–Si junctions were obtained and the current as a function of voltage properties were measured.

Fabrication of regular three-dimensional lattices of submicron silicon clusters in an SiO2 opal matrix

Silicon is now the most important material in modern solid-state electronics. Regular systems of silicon nanoclusters containing up to 1014 cm−3 elements were obtained in a sublattice of opal (SiO2) voids. By using three-dimensional dielectric matrix-carriers similar to opal, it may be possible to obtain three-dimensional ensembles of semiconductor nanodevices. Various parameters of these “opal-silicon” nanocomposites were measured.