Nanoengineering of Anisotropic Materials for Creating the Active Optical Cells with Increased Energy Efficiency

In this paper the state-of-the-art for exploiting the unique physical and chemical properties of crystalline materials and their possible applications for development of crystalline nanocomposites with the tailored anisotropy were discussed. Using a method of growing crystals from a solution the KDP and TGS nanocrystalites were grown in the mezopores of the Al2O3 matrix. To investigate the developed nanocrystalline samples the X-ray analysis was used. A form of the obtained diffractograms and our calculations show the predominant crystallization of the KDP and TGS in the direction [100], which coincides with the direction of the cylindrical pores. Thus, diffractograms contain only reflexes of crystallographic planes (200) and (400). The achieved result indicates the possibility of growing of nanocrystals in mesopores of such Al2O3 structures developed by us and provides the prospect of creating optical cells with increased energy efficiency

The Optimal Geometry of the Acousto-Optic Interaction in Selected Crystalline Materials Determined by Extreme Surfaces Method

The optimal geometries of the acousto-optic interaction are determined by extreme surfaces method for a number of acousto-optic crystals

Application of retardation-modulation polarimetry in studies of nanocomposite materials

We demonstrate an application of retardation-modulation polarimetry in studies of nanocomposite materials. Molecular ordering is explored on both nonchiral and chiral liquid crystals (LCs) in the bulk state and embedded into parallel-arrays of cylindrical channels of alumina or silica membranes of different channel sizes (12-42 nm). Two arms polarimetry serves for simultaneous measurements of the birefringence retardation and optical activity characterizing, respectively, orientational molecular ordering and chiral structuring inside nanochannels.Comment: Conference article, 5 pages, 5 figure

CdS Nanocrystallines: Synthesis, Structure and Nonlinear Optical Properties

We report the synthesis, structure and nonlinear optical properties of cadmium sulphide (CdS) nanocrystallines (NCs) synthesized electrochemically both with and without detergent ATLAS G3300. Relevant structural and morphological features are explored by X-ray diffraction and scanning electron microscopy (SEM) techniques. The efficiency of the second harmonic generation (SHG) appears to be strongly dependent on the energy density of the incident fundamental laser radiation and NC sizes.Comment: 2020 IEEE 15th International Conference on Advanced Trends in Radioelectronics, Telecommunications and Computer Engineering (TCSET), Conference Location: Lviv-Slavske, Ukraine, 25-29 February 2020, 5 pages, 8 figures, 3 table

Calcium Tungstate is a Perspective Acousto-Optic Material. Photoelastic Properties

Abstract -Acousto-optic modulators are main component of communication fibre-optic systems. From the other side the studies of the absolute piezo-optic effect (POE) are one of the important steps to estimate the acousto-optic efficiency of optical materials. In this article the investigation results of POE in calcium tungstate crystals (CaWO 4 ) has been represented. It is also proved that this crystal is essentially better acousto-optic material in comparison with lithium niobate (LiNbO 3 ) widely used in acousto-optic devices. Keywords -acousto-optic efficiency, elastic constants, piezo-and elastooptic coefficients, interferometric method The absolute piezo-optic coefficients (POCs) have been studied using the interferometric method taking into account the real lack of parallelism of sample faces. eliminates the influence of inconsiderable sample wedgeshaping on the error, indices m, k, i denote the directions of one axis pressure, light propagation and is polarization accordingly, is the wave length. Experimental values fort the main geometries of the experiment (i, m = 1, 2, 3) has been given in the table 1. The sign "+" or "-" at values of control stresses denote the increasing or decreasing of the natural optical light beam path induced by the change of the light path through the one axis. Besides that is necessary to take into account, that to the mechanical compression stresses assigned the "minus" sign. The estimated values of the main coefficients im are given in the tabl. 2. + ) and is ± 10% (is verified by multiple measurements), and the error of the second summand is caused of the elastic coefficient S km (± 5%). We see in the tabl. 2, that POE value of the calcium tungstate is greater as POE of lithium niobate: the corresponding POC of CaWO 4 crystals are more then ~ 2-7 times higher, and the sum of absolute values of im is 3 times higher. Nevertheless for estimating the acousto-optic efficiency of calcium tungstate it is necessary to determine the elastooptic coefficients (EOCs) p in , using the determined im and known tensor relation p in = im mn , where mn denote the elastic stiffness constants

Nanoarhitectonics of Inorganic–Organic Silica–Benzil Composites: Synthesis, Nanocrystal Morphology and Micro-Raman Analysis

The synthesis of nanosized organic benzil (C6H5CO)2 crystals within the mesoporous SiO2 host matrix was investigated via X-ray diffraction, transmission electron microscopy, Raman spectroscopy, and ab initio lattice dynamics analysis. Combining these methods, we have proved that the main structural properties of benzil nanocrystals embedded into SiO2 host membranes with pore diameters of 6.0, 7.8, 9.4, and 13.0 nm are preserved compared to a bulk benzil crystal. Space confinement has an insignificant impact on the lattice vibrational properties of benzil crystals implanted into the host matrices. The ab initio lattice dynamics calculation of the phonon spectrum in the Brillouin zone center shows the mechanical and dynamical stability of benzil lattice, revealing very low optical frequency of 11 cm−1 at point Γ

Manufacture technology of nanocrystallites based on Al 2 O 3 nanoporous membranes with saturated aqueous solution KH 2 PO 4 for telecommunication systems

Prepared nanoporous structures of anodized aluminum oxide Al2O3 (AOA) with a pore diameter of 40 and 75 nm. The crystal material KH2PO4 (KDP) in the form of nanowires and nanotubes at different growth variants from aqueous solution on nanoporous Al2O3 matrices was obtained and studied

Second harmonic generation on crystalline organic nanoclusters under extreme nanoconfinement in functionalized silica–benzil composites

Abstract We demonstrate a series of organic–inorganic nanocomposite materials combining the mesoporous silica (PS) and benzil (BZL) nanocrystals embedded into its nanochannels (6.0–13.0 nm in diameter) by capillary crystallization. One aims to design novel, efficient nonlinear optical composite materials in which inactive amorphous host PS-matrix provides a tubular scaffold structure, whereas nonlinear optical functionality results from specific properties of the deposited guest BZL-nanocrystals. A considerable contraction of the BZL melt during its crystallization inside the silica nanochannels results in a formation of the texture consisting of (221)- and (003)-oriented BZL nanoclusters (22 nm in length), separated by voids. Specificity of the textural morphology similarly to the spatial confinement significantly influences the nonlinear optical features of composite PS:BZL materials being explored in the second harmonic generation (SHG) experiment. The light polarization anisotropy of the SHG response appears to be considerably reduced at channel diameters larger than 7 nm apparently due to the multiple scattering and depolarization of the light on randomly distributed and crystallographically oriented BZL-nanoclusters. The normalized SHG response decreases nonlinearly by more than one order of magnitude as the channel diameter decreases from 13.0 to 6.0 nm and vanishes when spatial cylindrical confinement approaches the sizes of a few molecular layers suggesting that the embedded BZL clusters indeed are not uniformly crystalline but are characterized by more complex morphology consisting of a disordered SHG-inactive amorphous shell, covering the channel wall, and SHG-active crystalline core. Understanding and controlling of the textural morphology in inorganic–organic nanocrystalline composites as well as its relationships with nonlinear optical properties can lead to the development of novel efficient nonlinear optical materials for the light energy conversion with prospective optoelectronic and photonic applications