WorldWideScience

Sample records for optical inorganic dielectric

  1. Optics of dielectric microstructures

    DEFF Research Database (Denmark)

    Søndergaard, Thomas

    2002-01-01

    From the work carried out within the ph.d. project two topics have been selected for this thesis, namely emission of radiation by sources in dielectric microstructures, and planar photonic crystal waveguides. The work done within the first topic, emission of radiation by sources in dielectric...... microstructures, will be presented in the part I of this thesis consisting of the chapters 2-5. An introductions is given in chapter 2. In part I three methods are presented for calculating spontaneous and classical emission from sources in dielectric microstructures. The first method presented in chapter 3...... is based on the Fermi Golden Rule, and spontaneous emission from emitters in a passive dielectric microstructure is calculated by summing over the emission into each electromagnetic mode of the radiation field. This method is applied to investigate spontaneous emission in a two-dimensional photonic crystal...

  2. Dielectric optical antenna thermal emitters and metamaterials

    Science.gov (United States)

    Schuller, Jonathan Aaron

    Optical antennas are critical components in nanophotonics research due to their unparalleled ability to concentrate electromagnetic energy into nanoscale volumes. Researchers typically construct such antennas from wavelength-size metallic structures. However, recent research has begun to exploit the scattering resonances of high-permittivity particles to realize all-dielectric optical antennas, emitters, and metamaterials. In this thesis, we experimentally and theoretically characterize the resonant modes of subwavelength rod-shaped dielectric particles and demonstrate their use in negative index metamaterials and novel infrared light emitters. At mid-infrared frequencies, Silicon Carbide (SiC) is an ideal system for studying the behavior of dielectric optical antennas. At frequencies below the TO phonon resonance, SiC behaves like a dielectric with very large refractive index. Using infrared spectroscopy and analytical Mie calculations we show that individual rod-shaped SiC particles exhibit a multitude of resonant modes. Detailed investigations of these SiC optical antennas reveal a wealth of new physics and applications. We discuss the distinct electromagnetic field profile for each mode, and demonstrate that two of the dielectric-type Mie resonances can be combined in a particle array to form a negative index metamaterial. We further show that these particles can serve as "broadcasting" antennas. Using a custom-built thermal emission microscope we collect emissivity spectra from single SiC particles at elevated temperatures, highlighting their use as subwavelength resonant light emitters. Finally, we derive and verify a variety of general analytical results applicable to all cylindrical dielectric antennas.

  3. Dielectric Optical Antenna Emitters and Metamaterials

    Science.gov (United States)

    Schuller, Jon

    2009-03-01

    Optical antennas are critical components in nanophotonics research due to their unparalleled ability to concentrate electromagnetic energy into nanoscale volumes. Researchers typically construct such antennas from wavelength-size metallic structures. However, recent research has begun to exploit the scattering resonances of high-permittivity particles to realize all-dielectric optical antennas, emitters, and metamaterials. In this talk, we experimentally and theoretically characterize the resonant modes of subwavelength rod-shaped dielectric particles and demonstrate their use in negative index metamaterials and novel infrared light emitters. At mid-infrared frequencies, Silicon Carbide (SiC) is an ideal system for studying the behavior of dielectric optical antennas. At frequencies below the TO phonon resonance, SiC behaves like a dielectric with very large refractive index. Using infrared spectroscopy and analytical Mie calculations we show that individual rod-shaped SiC particles exhibit a multitude of resonant modes. Detailed investigations of these SiC optical antennas reveal a wealth of new physics and applications. We discuss the distinct electromagnetic field profile for each mode, and demonstrate that two of the dielectric-type Mie resonances can be combined in a particle array to form a negative index metamaterial [1]. We further show that these particles can serve as ``broadcasting'' antennas. Using a custom-built thermal emission microscope we collect emissivity spectra from single SiC particles at elevated temperatures, highlighting their use as subwavelength resonant light emitters. Finally, we derive and verify a variety of general analytical results applicable to all cylindrical dielectric antennas and discuss extensions of the demonstrated concepts to different materials systems and frequency regimes. [1] J.A. Schuller, et al., Phys. Rev. Lett. 99, 107401 (2007)

  4. Optical dielectric function of intrinsic amorphous silicon

    International Nuclear Information System (INIS)

    Ching, W.Y.; Lin, C.C.

    1978-01-01

    The imaginary part of the optical dielectric function epsilon 2 (ω) has been calculated using a continuous-random-tetrahedral network as the structural model for the atomic positions. Here the electronic energies and wave functions are determined by first-principles calculations with the method of linear combinations of atomic orbitals (LCAO), and the momentum matrix elements are evaluated directly from the LCAO wave functions. The calculated dielectric function is in good overall agreement with experiment. At energies within 1 eV above the threshold, the epsilon 2 curve shows some structures that are due to interband transitions between the localized states near the band gap

  5. Information authentication using an optical dielectric metasurface

    International Nuclear Information System (INIS)

    Wang, Xiaogang; Mei, Shengtao

    2017-01-01

    Metasurfaces that consist of a monolayer of photonic artificial atoms are emerging as attractive materials for optical wavefront-shaping and polarization-control devices. By integrating nanophotonics with a phase-encoding technique, we demonstrate theoretically an information authentication method using dielectric metasurfaces that can be verified without information disclosure at visible wavelengths. The required secured diffraction pattern can be simply achieved by a metasurface hologram with a small number of pixels, which means increased efficiency and lower costs of production. Although the decrypted image is noisy, it can be authenticated by recognition algorithms where the primary image is used as a reference. The results show that the dielectric metasurface approach, providing great flexibility in the design of the wavefront of light and compatible with the CMOS technology, can be potentially applied in optical information security. (letter)

  6. Quantum confinement and dielectric profiles of colloidal nanoplatelets of halide inorganic and hybrid organic-inorganic perovskites

    Science.gov (United States)

    Sapori, Daniel; Kepenekian, Mikaël; Pedesseau, Laurent; Katan, Claudine; Even, Jacky

    2016-03-01

    Quantum confinement as well as high frequency ε∞ and static εs dielectric profiles are described for nanoplatelets of halide inorganic perovskites CsPbX3 (X = I, Br, Cl) and hybrid organic-inorganic perovskites (HOP) in two-dimensional (2D) and three-dimensional (3D) structures. 3D HOP are currently being sought for their impressive photovoltaic ability. Prior to this sudden popularity, 2D HOP materials were driving intense activity in the field of optoelectronics. Such developments have been enriched by the recent ability to synthesize colloidal nanostructures of controlled sizes of 2D and 3D HOP. This raises the need to achieve a thorough description of the electronic structure and dielectric properties of these systems. In this work, we go beyond the abrupt dielectric interface model and reach the atomic scale description. We examine the influence of the nature of the halogen and of the cation on the band structure and dielectric constants. Similarly, we survey the effect of dimensionality and shape of the perovskite. In agreement with recent experimental results, we show an increase of the band gap and a decrease of ε∞ when the size of a nanoplatelet reduces. By inspecting 2D HOP, we find that it cannot be described as a simple superposition of independent inorganic and organic layers. Finally, the dramatic impact of ionic contributions on the dielectric constant εs is analysed.Quantum confinement as well as high frequency ε∞ and static εs dielectric profiles are described for nanoplatelets of halide inorganic perovskites CsPbX3 (X = I, Br, Cl) and hybrid organic-inorganic perovskites (HOP) in two-dimensional (2D) and three-dimensional (3D) structures. 3D HOP are currently being sought for their impressive photovoltaic ability. Prior to this sudden popularity, 2D HOP materials were driving intense activity in the field of optoelectronics. Such developments have been enriched by the recent ability to synthesize colloidal nanostructures of controlled

  7. Inorganic-organic nanocomposites for optical coatings

    Science.gov (United States)

    Schmidt, Helmut K.; Krug, Herbert; Sepeur-Zeitz, Bernhard; Geiter, Elisabeth

    1997-10-01

    The fabrication of nanoparticles by the sol-gel process and their use in polymeric or sol-gel-derived inorganic-organic composite matrices opens up interesting possibilities for designing new optical materials. Two different routes have been chosen for preparing optical nanocomposites: The first is the so-called 'in situ route,' where the nanoparticles are synthesized in a liquid mixture from Zr-alkoxides in a polymerizable system and diffractive gratings were produced by embossing uncured film. The second is the 'separate' preparation route, where a sterically stabilized dry nanoboehmite powder was completely redispersed in an epoxy group-containing matrix and hard coatings with optical quality on polycarbonate were prepared.

  8. Structural, optical spectroscopy, optical conductivity, dielectric ...

    Indian Academy of Sciences (India)

    13

    different methods of preparation [36-41]. The electrical insulator materials with low refractive index and low absorption are needed for various optical devices, such as low loss waveguides, resonators, photonic crystals, distributed Bragg reflectors, light-emitting diodes, passive splitters, biosensors, attenuators and filters ...

  9. Spectroscopy and Biosensing with Optically Resonant Dielectric Nanostructures

    OpenAIRE

    Krasnok, Alex; Caldarola, Martin; Bonod, Nicolas; Alú, Andrea

    2017-01-01

    Resonant dielectric nanoparticles (RDNs) made of materials with large positive dielectric permittivity, such as Si, GaP, GaAs, have become a powerful platform for modern light science, enabling various fascinating applications in nanophotonics and quantum optics. In addition to light localization at the nanoscale, dielectric nanostructures provide electric and magnetic resonant responses throughout the visible and infrared spectrum, low dissipative losses and optical heating, low doping effec...

  10. Structural, optical and dielectric properties of graphene oxide

    Science.gov (United States)

    Bhargava, Richa; Khan, Shakeel

    2018-05-01

    The Modified Hummers method has been used to synthesize Graphene oxide nanoparticles. Microstructural analyses were carried out by X-ray diffraction and Fourier transform infrared spectroscopy. Optical properties were studied by UV-visible spectroscopy in the range of 200-700 nm. The energy band gap was calculated with the help of Tauc relation. The frequency dependence of dielectric constant and dielectric loss were studied over a range of the frequency 75Hz to 5MHz at room temperature. The dispersion in dielectric constant can be explained with the help of Maxwell-Wagner model in studied nanoparticles.

  11. Quantum optics of dispersive dielectric media

    International Nuclear Information System (INIS)

    Lenac, Z.

    2003-01-01

    We quantize the electromagnetic field in a polar medium starting with the fundamental equations of motion. In our model the medium is described by a Lorenz-type dielectric function ε(r,ω) appropriate, e.g., for ionic crystals, metals, and inert dielectrics. There are no restrictions on the spatial behavior of the dielectric function, i.e., there can be many different polar media with arbitrary shapes. We assume no losses in our system so the dielectric function for the whole space is assumed as real. The quantization procedure is based on an expansion of the total field (transverse and longitudinal) in terms of the coupled (polariton) eigenmodes, and this approach incorporates all previous results derived for similar but restricted systems (e.g., without spatial or frequency dependence of coupled modes). Within the same model, we also quantize the Hamiltonian of a nonretarded electromagnetic field in polar media. Particular attention is paid to the derivation of the orthogonality and closure relations, which are used in a discussion of the fundamental (equal-time) commutation relations between the conjugate field operators

  12. Dielectric barrier discharges applied for optical spectrometry

    Czech Academy of Sciences Publication Activity Database

    Brandt, S.; Schütz, A.; Klute, F. D.; Kratzer, Jan; Franzke, J.

    2016-01-01

    Roč. 123, SEP (2016), s. 6-32 ISSN 0584-8547 R&D Projects: GA ČR GA14-23532S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * analytical spectroscopy * applications Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 3.241, year: 2016

  13. Dielectric barrier discharges applied for optical spectrometry

    Czech Academy of Sciences Publication Activity Database

    Brandt, S.; Schütz, A.; Klute, F. D.; Kratzer, Jan; Franzke, J.

    2016-01-01

    Roč. 123, SEP (2016), s. 6-32 ISSN 0584-8547 R&D Projects: GA ČR GA14-23532S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * analytical spectroscopy * applications Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.241, year: 2016

  14. Decolorization of reactive black 5 using dielectric barrier discharge in the presence of inorganic salts

    Directory of Open Access Journals (Sweden)

    Dojčinović Biljana P.

    2012-01-01

    Full Text Available Inorganic salts improve the coloration of textiles, which increase pollution load on dyehouse effluent in general. Decolorization of reactive textile dye C.I. Reactive Black 5 was studied using Advanced Oxidation Processes (AOPs in a non-thermal plasma reactor, based on coaxial water falling film Dielectric Barrier Discharge (DBD. Initial dye concentration in the solution was 40.0 mg L-1. The effects of addition of inorganic salt different high concentrations (NaCl, Na2SO4 and Na2CO3 on the degree of decolorization were studied. Recirculation of dye solution through the DBD reactor with applied energy density 45-315 kJ L-1 was used. The influence of residence time was investigated after 5 minutes and 24 hours of plasma treatment. Decolorization of the dyes was monitored by spectrophotometric measurement. Changes of pH values and the conductivity of dye solution after each recirculation were tested. The most effective decolorization of over 90% was obtained with the addition of NaCl (50 g L-1, applied energy density of 135 kJ L-1 and after residence time of 24 hours of plasma treatment. Decolorization of solutions containing inorganic salts Na2SO4 and Na2CO3 were lower than for the solution without salt.

  15. Optical characterization of directly deposited graphene on a dielectric substrate

    DEFF Research Database (Denmark)

    Kaplas, Tommi; Karvonen, Lasse; Ahmadi, Sepehr

    2016-01-01

    By using scanning multiphoton microscopy we compare the nonlinear optical properties of the directly deposited and transferred to the dielectric substrate graphene. The direct deposition of graphene on oxidized silicon wafer was done by utilizing sacrificial copper catalyst film. We demonstrate...

  16. Intracellular dielectric tagging for improved optical manipulation of mammalian cells

    CSIR Research Space (South Africa)

    Mthunzi, P

    2010-05-01

    Full Text Available review the application of optical forces for cellmanipulation and sorting, highlighting some of the key experiments over the last twenty years.We then introduce a new technique for enhancing the dielectric contrast of mammalian cells, which is a result...

  17. Synthesis, growth, and structural, optical, mechanical, electrical properties of a new inorganic nonlinear optical crystal: Sodium manganese tetrachloride (SMTC

    Directory of Open Access Journals (Sweden)

    M. Packiya raj

    2017-01-01

    Full Text Available A new inorganic nonlinear optical single crystal of sodium manganese tetrachloride (SMTC has been successfully grown from aqueous solution using the slow evaporation technique at room temperature. The crystals obtained using the aforementioned method were characterized using different techniques. The crystalline nature of the as-grown crystal of SMTC was analyzed using powder X-ray diffraction. Single-crystal X-ray diffraction revealed that the crystal belongs to an orthorhombic system with non-centrosymmetric space group Pbam. The optical transmission study of the SMTC crystal revealed high transmittance in the entire UV–vis region, and the lower cut-off wavelength was determined to be 240 nm. The mechanical strength of the as-grown crystal was estimated using the Vickers microhardness test. The second harmonic generation (SHG efficiency of the crystal was measured using Kurtz's powder technique, which indicated that the crystal has a nonlinear optical (NLO efficiency that is 1.32 times greater than that of KDP. The dielectric constant and dielectric loss of the compound were measured at different temperatures with varying frequencies. The photoconductivity study confirmed that the title compound possesses a negative photoconducting nature. The growth mechanism and surface features of the as-grown crystals were investigated using chemical etching analysis.

  18. Processing of Dielectric Optical Coatings by Nanosecond and Femtosecond UV Laser Ablation

    International Nuclear Information System (INIS)

    Ihlemann, J.; Bekesi, J.; Klein-Wiele, J.H.; Simon, P.

    2008-01-01

    Micro processing of dielectric optical coatings by UV laser ablation is demonstrated. Excimer laser ablation at deep UV wavelengths (248 nm, 193 nm) is used for the patterning of thin oxide films or layer stacks. The layer removal over extended areas as well as sub-μm-structuring is possible. The ablation of SiO2, Al2O3, HfO2, and Ta2O5 layers and layer systems has been investigated. Due to their optical, chemical, and thermal stability, these inorganic film materials are well suited for optical applications, even if UV-transparency is required. Transparent patterned films of SiO2 are produced by patterning a UV-absorbing precursor SiOx suboxide layer and oxidizing it afterwards to SiO2. In contrast to laser ablation of bulk material, in the case of thin films, the layer-layer or layer-substrate boundaries act as predetermined end points, so that precise depth control and a very smooth surface can be achieved. For large area ablation, nanosecond lasers are well suited; for patterning with submicron resolution, femtosecond excimer lasers are applied. Thus the fabrication of optical elements like dielectric masks, pixelated diffractive elements, and gratings can be accomplished.

  19. Optimization of extraordinary optical absorption in plasmonic and dielectric structures

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Sigmund, Ole

    2013-01-01

    Extraordinary optical absorption (EOA) can be obtained by plasmonic surface structuring. However, studies that compare the performance of these plasmonic devices with similar structured dielectric devices are rarely found in the literature. In this work we show different methods to enhance the EOA...... by optimizing the geometry of the surface structuring for both plasmonic and dielectric devices, and the optimized performances are compared. Two different problem types with periodic structures are considered. The first case shows that strips of silicon on a surface can increase the absorption in an underlying...... it is important to compare the absorption performance of plasmonic devices with similarly structured dielectric devices in order to find the best possible solution....

  20. Computational simulation of electron and ion beams interaction with solid high-molecular dielectrics and inorganic glasses

    International Nuclear Information System (INIS)

    Milyavskiy, V.V.

    1998-01-01

    Numerical investigation of interaction of electron beams (with the energy within the limits 100 keV--20 MeV) and ion beams (with the energy over the range 1 keV--50 MeV) with solid high-molecular dielectrics and inorganic glasses is performed. Note that the problem of interaction of electron beams with glass optical covers is especially interesting in connection with the problem of radiation protection of solar power elements on cosmic satellites and stations. For computational simulation of the above-mentioned processes a mathematical model was developed, describing the propagation of particle beams through the sample thickness, the accumulation and relaxation of volume charge and shock-wave processes, as well as the evolution of electric field in the sample. The calculation of energy deposition by electron beam in a target in the presence of nonuniform electric field was calculated with the assistance of the semiempirical procedure, formerly proposed by author of this work. Propagation of the low energy ions through the sample thickness was simulated using Pearson IV distribution. Damage distribution, ionization distribution and range distribution was taken into account. Propagation of high energy ions was calculated in the approximation of continuous deceleration. For description of hydrodynamic processes the system of equations of continuum mechanics in elastic-plastic approximation and the wide-range equation of state were used

  1. Optical properties of crystalline semiconductors and dielectrics

    International Nuclear Information System (INIS)

    Forouhi, A.R.; Bloomer, I.

    1988-01-01

    A new formulation for the complex index of refraction, N(E) = n(E)-ik(E), as a function of photon energy E, for crystalline semiconductors and dielectrics is developed based on our previous derivation of N(E) for amorphous materials. The extinction coefficient k(E) is deduced from a one-electron model with finite lifetime for the excited electron state. The refractive index n(E) is then derived from the Kramers-Kronig relation as the Hilbert transform of k(E). It is shown that n(∞)>1. Excellent agreement is found between our equations for n(E) and k(E) and published measured values for crystalline Si, Ge, GaP, GaAs, GaSb, InP, InAs, InSb, SiC, cubic C, and α-SiO 2 , over a wide range of energies (∼0--20 eV). Far fewer parameters, all of which have physical significance, are required and they can be determined for a particular material from the position and strength of the peaks in the k spectrum

  2. Structural, optical, photoluminescence, dielectric and electrical ...

    Indian Academy of Sciences (India)

    The optical band gap of thin films was found to allow direct tran- sition with energy ... Cadmium telluride (CdTe) is an important group II–VI semi- ... Extensive research was done in the last two decades on CdTe ... 3.1 X-ray diffraction analysis.

  3. Cooling optically levitated dielectric nanoparticles via parametric feedback

    Science.gov (United States)

    Neukirch, Levi; Rodenburg, Brandon; Bhattacharya, Mishkatul; Vamivakas, Nick

    2015-05-01

    The inability to leverage resonant scattering processes involving internal degrees of freedom differentiates optical cooling experiments performed with levitated dielectric nanoparticles, from similar atomic and molecular traps. Trapping in optical cavities or the application of active feedback techniques have proven to be effective ways to circumvent this limitation. We present our nanoparticle optical cooling apparatus, which is based on parametric feedback modulation of a single-beam gradient force optical trap. This scheme allows us to achieve effective center-of-mass temperatures well below 1 kelvin for our ~ 1 ×10-18 kg particles, at modest vacuum pressures. The method provides a versatile platform, with parameter tunability not found in conventional tethered nanomechanical systems. Potential applications include investigations of nonequilibrium nanoscale thermodynamics, ultra-sensitive force metrology, and mesoscale quantum mechanics and hybrid systems. Supported by the office of Naval Research award number N000141410442.

  4. Optically levitating dielectrics in the quantum regime: Theory and protocols

    International Nuclear Information System (INIS)

    Romero-Isart, O.; Pflanzer, A. C.; Cirac, J. I.; Juan, M. L.; Quidant, R.; Kiesel, N.; Aspelmeyer, M.

    2011-01-01

    We provide a general quantum theory to describe the coupling of light with the motion of a dielectric object inside a high-finesse optical cavity. In particular, we derive the total Hamiltonian of the system as well as a master equation describing the state of the center-of-mass mode of the dielectric and the cavity-field mode. In addition, a quantum theory of elasticity is used to study the coupling of the center-of-mass motion with internal vibrational excitations of the dielectric. This general theory is applied to the recent proposal of using an optically levitating nanodielectric as a cavity optomechanical system [see Romero-Isart et al., New J. Phys. 12, 033015 (2010); Chang et al., Proc. Natl. Acad. Sci. USA 107, 1005 (2010)]. On this basis, we also design a light-mechanics interface to prepare non-Gaussian states of the mechanical motion, such as quantum superpositions of Fock states. Finally, we introduce a direct mechanical tomography scheme to probe these genuine quantum states by time-of- flight experiments.

  5. Refraction at a curved dielectric interface - Geometrical optics solution

    Science.gov (United States)

    Lee, S.-W.; Sheshadri, M. S.; Mittra, R.; Jamnejad, V.

    1982-01-01

    The transmission of a spherical or plane wave through an arbitrarily curved dielectric interface is solved by the geometrical optics theory. The transmitted field is proportional to the product of the conventional Fresnel's transmission coefficient and a divergence factor (DF), which describes the cross-sectional variation (convergence or divergence) of a ray pencil as the latter propagates in the transmitted region. The factor DF depends on the incident wavefront, the curvatures of the interface, and the relative indices of the two media. Explicit matrix formulas for calculating DF are given, and its physical significance is illustrated via examples.

  6. Structural, optical, morphological and dielectric properties of cerium oxide nanoparticles

    International Nuclear Information System (INIS)

    Prabaharan, Devadoss Mangalam Durai Manoharadoss; Sadaiyandi, Karuppasamy; Mahendran, Manickam; Sagadevan, Suresh

    2016-01-01

    Cerium oxide (CeO 2 ) nanoparticles were prepared by the precipitation method. The average crystallite size of cerium oxide nanoparticles was calculated from the X-ray diffraction (XRD) pattern and found to be 11 nm. The FT-IR spectrum clearly indicated the strong presence of cerium oxide nanoparticles. Raman spectrum confirmed the cubic nature of the cerium oxide nanoparticles. The Scanning Electron Microscopy (SEM) analysis showed that the nanoparticles agglomerated forming spherical-shaped particles. The Transmission Electron Microscopic (TEM) analysis confirmed the prepared cerium oxide nanoparticles with the particle size being found to be 16 nm. The optical absorption spectrum showed a blue shift by the cerium oxide nanoparticles due to the quantum confinement effect. The dielectric properties of cerium oxide nanoparticles were studied for different frequencies at different temperatures. The dielectric constant and the dielectric loss of the cerium oxide nanoparticles decreased with increase in frequency. The AC electrical conductivity study revealed that the conduction depended on both the frequency and the temperature. (author)

  7. Structural, optical, morphological and dielectric properties of cerium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Prabaharan, Devadoss Mangalam Durai Manoharadoss [Department of Physics, NPR College of Engineering and Technology, Natham, Dindigul, Tamil Nadu (India); Sadaiyandi, Karuppasamy [Department of Physics, Alagappa Government Arts College, Karaikudi, Sivaganga, Tamil Nadu (India); Mahendran, Manickam [Department of Physics, Thiagarajar College of Engineering, Madurai, Tamil Nadu (India); Sagadevan, Suresh, E-mail: duraiphysics2011@gmail.com [Department of Physics, AMET University (India)

    2016-03-15

    Cerium oxide (CeO{sub 2}) nanoparticles were prepared by the precipitation method. The average crystallite size of cerium oxide nanoparticles was calculated from the X-ray diffraction (XRD) pattern and found to be 11 nm. The FT-IR spectrum clearly indicated the strong presence of cerium oxide nanoparticles. Raman spectrum confirmed the cubic nature of the cerium oxide nanoparticles. The Scanning Electron Microscopy (SEM) analysis showed that the nanoparticles agglomerated forming spherical-shaped particles. The Transmission Electron Microscopic (TEM) analysis confirmed the prepared cerium oxide nanoparticles with the particle size being found to be 16 nm. The optical absorption spectrum showed a blue shift by the cerium oxide nanoparticles due to the quantum confinement effect. The dielectric properties of cerium oxide nanoparticles were studied for different frequencies at different temperatures. The dielectric constant and the dielectric loss of the cerium oxide nanoparticles decreased with increase in frequency. The AC electrical conductivity study revealed that the conduction depended on both the frequency and the temperature. (author)

  8. Floating dielectric slab optical interconnection between metal-dielectric interface surface plasmon polariton waveguides.

    Science.gov (United States)

    Kang, Minsu; Park, Junghyun; Lee, Il-Min; Lee, Byoungho

    2009-01-19

    A simple and effective optical interconnection which connects two distanced single metal-dielectric interface surface plasmon waveguides by a floating dielectric slab waveguide (slab bridge) is proposed. Transmission characteristics of the suggested structure are numerically studied using rigorous coupled wave analysis, and design rules based on the study are given. In the wave-guiding part, if the slab bridge can support more than the fundamental mode, then the transmission efficiency of the interconnection shows strong periodic dependency on the length of the bridge, due to the multi-mode interference (MMI) effect. Otherwise, only small fluctuation occurs due to the Fabry-Pérot effect. In addition, light beating happens when the slab bridge is relatively short. In the wave-coupling part, on the other hand, gap-assisted transmission occurs at each overlapping region as a consequence of mode hybridization. Periodic dependency on the length of the overlap region also appears due to the MMI effect. According to these results, we propose design principles for achieving both high transmission efficiency and stability with respect to the variation of the interconnection distance, and we show how to obtain the transmission efficiency of 68.3% for the 1mm-long interconnection.

  9. Beam coupling in hybrid photorefractive inorganic-cholesteric liquid crystal cells: Impact of optical rotation

    International Nuclear Information System (INIS)

    Reshetnyak, V. Yu.; Pinkevych, I. P.; Sluckin, T. J.; Cook, G.; Evans, D. R.

    2014-01-01

    We develop a theoretical model to describe two-beam energy exchange in a hybrid photorefractive inorganic-cholesteric cell. A cholesteric layer is placed between two inorganic substrates. One of the substrates is photorefractive (Ce:SBN). Weak and strong light beams are incident on the hybrid cell. The interfering light beams induce a periodic space-charge field in the photorefractive window. This penetrates into the cholesteric liquid crystal (LC), inducing a diffraction grating written on the LC director. In the theory, the flexoelectric mechanism for electric field-director coupling is more important than the LC static dielectric anisotropy coupling. The LC optics is described in the Bragg regime. Each beam induces two circular polarized waves propagating in the cholesteric cell with different velocities. The model thus includes optical rotation in the cholesteric LC. The incident light beam wavelength can fall above, below, or inside the cholesteric gap. The theory calculates the energy gain of the weak beam, as a result of its interaction with the pump beam within the diffraction grating. Theoretical results for exponential gain coefficients are compared with experimental results for hybrid cells filled with cholesteric mixture BL038/CB15 at different concentrations of chiral agent CB15. Reconciliation between theory and experiment requires the inclusion of a phenomenological multiplier in the magnitude of the director grating. This multiplier is cubic in the space-charge field, and we provide a justification of the q-dependence of the multiplier. Within this paradigm, we are able to fit theory to experimental data for cholesteric mixtures with different spectral position of cholesteric gap relative to the wavelength of incident beams, subject to the use of some fitting parameters

  10. Effect of dielectric confinement on optical properties of colloidal nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Rodina, A. V., E-mail: anna.rodina@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation); Efros, Al. L., E-mail: efros@nrl.navy.mil [Naval Research Laboratory (United States)

    2016-03-15

    We review the effects caused by a large difference in the dielectric constants of a semiconductor and its surrounding in colloidal semiconductor nanostructures (NSs) with various shapes, e.g., nanocrystals, nanorods, and nanoplatelets. The difference increases the electron–hole interaction and consequently the exciton binding energy and its oscillator transition strength. On the other hand, this difference reduces the electric field of a photon penetrating the NS (the phenomenon is called the local field effect) and reduces the photon coupling to an exciton. We show that the polarization properties of the individual colloidal NSs as well as of their randomly oriented ensemble are determined both by the anisotropy of the local field effect and by the symmetry of the exciton states participating in optical transitions. The calculations explain the temperature and time dependences of the degree of linear polarization measured in an ensemble of CdSe nanocrystals.

  11. Optical and electrical phenomena in dielectric materials under irradiation

    CERN Document Server

    Plaksin, O A; Stepanov, P A; Demenkov, P V; Chernov, V M; Krutskikh, A O

    2002-01-01

    Optical and acoustic properties of the materials based on Al sub 2 O sub 3 , SiO sub 2 and BN under 8 MeV proton irradiation (<10 sup 4 Gy/s) have been measured. Electric charge partitioning has been shown to result in charging the microscopic regions in the bulk of the dielectrics under irradiation, which is due to different mobility of free electrons and holes (sapphire), concentration inhomogeneity in the system of charge carrier traps (alumina), or thermodynamic instability of the homogeneous distribution of the filled traps (silica glasses). Prevalent charge carrier recombination in the grain boundaries causes re-crystallization of pyrolytic boron nitride under irradiation, which shows up as simultaneous decrease of the intensity of radiation-induced luminescence (RIL) of the centres in the grain boundaries and the BN. The local charging results in optical inhomogeneity of the silica glasses which is sustained by the optical loss spectra of the irradiated glasses, features of kinetics of bleaching, RI...

  12. THz - ToF Optical Layer Analysis (OLA) to determine optical properties of dielectric materials

    Science.gov (United States)

    Spranger, Holger; Beckmann, Jörg

    2017-02-01

    Electromagnetic waves with frequencies between 0.1 and 10 THz are described as THz-radiation (T-ray). The ability to penetrate dielectric materials makes T-rays attractive to reveal discontinuities in polymer and ceramic materials. THz-Time Domain Spectroscopy Systems (THz-TDS) are available on the market today which operates with THz-pulses transmitted and received by optically pumped semiconductor antennas. In THz-TDS the travelling time (ToF) and shape of the pulse is changed if it interacts with the dielectric material and its inherent discontinuities. A tomogram of the object under the test can be reconstructed from time of flight diffraction (ToFD) scans if a synthetic focusing aperture (SAFT) algorithm is applied. The knowledge of the base materials shape and optical properties is essential for a proper reconstruction result. To obtain these properties a model is assumed which describes the device under the test as multilayer structure composed of thin layers with different dielectric characteristics. The Optical Layer Analysis (OLA) is able to fulfill these requirements. A short description why the optical properties are crucial for meaningful SAFT reconstruction results will be given first. Afterwards the OLA will be derived and applied on representative samples to discuss and evaluate its benefits and limits.

  13. Accurate Measurement of the Optical Constants n and k for a Series of 57 Inorganic and Organic Liquids for Optical Modeling and Detection.

    Science.gov (United States)

    Myers, Tanya L; Tonkyn, Russell G; Danby, Tyler O; Taubman, Matthew S; Bernacki, Bruce E; Birnbaum, Jerome C; Sharpe, Steven W; Johnson, Timothy J

    2018-04-01

    For optical modeling and other purposes, we have created a library of 57 liquids for which we have measured the complex optical constants n and k. These liquids vary in their nature, ranging in properties that include chemical structure, optical band strength, volatility, and viscosity. By obtaining the optical constants, one can model most optical phenomena in media and at interfaces including reflection, refraction, and dispersion. Based on the works of others, we have developed improved protocols using multiple path lengths to determine the optical constants n/k for dozens of liquids, including inorganic, organic, and organophosphorus compounds. Detailed descriptions of the measurement and data reduction protocols are discussed; agreement of the derived optical constant n and k values with literature values are presented. We also present results using the n/k values as applied to an optical modeling scenario whereby the derived data are presented and tested for models of 1 µm and 100 µm layers for dimethyl methylphosphonate (DMMP) on both metal (aluminum) and dielectric (soda lime glass) substrates to show substantial differences between the reflected signal from highly reflective substrates and less-reflective substrates.

  14. Optical studies of metallo-dielectric photonic crystals

    Science.gov (United States)

    Kamaev, Vladimir

    2007-12-01

    Metallo-dielectric photonic crystals (MDPCs) are characterized by a large difference between the dielectric constants of the constituents. Owing to their high DC conductivity a broad omnidirectional band gap is formed at low frequencies. At the same time there exist numerous propagating electromagnetic modes at frequencies above a cutoff. This gives a possibility of creating a "transparent" metal: a crystal transparent in the visible spectral range and simultaneously having high DC conductivity. Since the cutoff wavelength linearly scales with the crystal periodicity, in order to make an MDPC with propagating modes in the visible range the crystal periodicity has to be around a quarter micrometer. Fabrication of such a crystal is a challenging task. One of the feasible choices is natural or artificial opals, structures made of silica balls arranged into a close packed fcc lattice. The ball diameters could vary from 200 nm to several microns, allowing the desired optical features to be in the visible spectral range. In the present work we studied metal-infiltrated opals numerically, analytically, and experimentally (Chapters 1 and 4). Both theory and experiment revealed high reflectance of the samples at large wavelengths associated with the low frequency metallic band gap formation, and low reflectance at short wavelengths that has characteristic wiggles. Contrarily, the absorbance is low in the IR region and goes up towards the UV end, which is due to low group velocity of light and high metal absorption in the region. Numerical analysis of thin metal-infiltrated opals (˜3-5 layers) did show a transmission peak around the first reflectance minimum and cutoff frequency. In Chapter 5 we present transmission experiments on thin metal films perforated with periodic arrays of holes or deposited on an opal monolayer. Both types of 2D MDPCs exhibited anomalous transmission peaks associated with surface plasma excitations. It was shown that the phenomenon could be

  15. Optical modelling data for room temperature optical properties of organic–inorganic lead halide perovskites

    Directory of Open Access Journals (Sweden)

    Yajie Jiang

    2015-06-01

    Full Text Available The optical properties of perovskites at ambient temperatures are important both to the design of optimised solar cells as well as in other areas such as the refinement of electronic band structure calculations. Limited previous information on the optical modelling has been published. The experimental fitting parameters for optical constants of CH3NH3PbI3−xClx and CH3NH3PbI3 perovskite films are reported at 297 K as determined by detailed analysis of reflectance and transmittance data. The data in this study is related to the research article “Room temperature optical properties of organic–inorganic lead halide perovskites” in Solar Energy Materials & Solar Cells [1].

  16. Optical trapping of metal-dielectric nanoparticle clusters near photonic crystal microcavities.

    Science.gov (United States)

    Mejia, Camilo A; Huang, Ningfeng; Povinelli, Michelle L

    2012-09-01

    We predict the formation of optically trapped, metal-dielectric nanoparticle clusters above photonic crystal microcavities. We determine the conditions on particle size and position for a gold particle to be trapped above the microcavity. We then show that strong field redistribution and enhancement near the trapped gold nanoparticle results in secondary trapping sites for a pair of dielectric nanoparticles.

  17. High resolution imaging of dielectric surfaces with an evanescent field optical microscope

    NARCIS (Netherlands)

    van Hulst, N.F.; Segerink, Franciscus B.; Bölger, B.

    1992-01-01

    An evanescent field optical microscope (EFOM) is presented which employs frustrated total internal reflection o­n a localized scale by scanning a dielectric tip in close proximity to a sample surface. High resolution images of dielectric gratings and spheres containing both topographic and

  18. Rare earth doped nanoparticles in organic and inorganic host materials for application in integrated optics

    NARCIS (Netherlands)

    Dekker, R.; Hilderink, L.T.H.; Diemeer, Mart; Stouwdam, J.W.; Sudarsan, V; van Veggel, F.C.J.M.; Driessen, A.; Worhoff, Kerstin; Misra, D; Masscher, P.; Sundaram, K.; Yen, W.M.; Capobianco, J.

    2006-01-01

    The preparation and the optical properties of lanthanum fluoride (LaF3) nanoparticles doped with erbium and neodymium will be discussed. Organic and inorganic materials in the form of polymers and sol-gels were used to serve as the hosts for the inorganic nanoparticles, respectively. The organic

  19. Geometrical-optics code for computing the optical properties of large dielectric spheres.

    Science.gov (United States)

    Zhou, Xiaobing; Li, Shusun; Stamnes, Knut

    2003-07-20

    Absorption of electromagnetic radiation by absorptive dielectric spheres such as snow grains in the near-infrared part of the solar spectrum cannot be neglected when radiative properties of snow are computed. Thus a new, to our knowledge, geometrical-optics code is developed to compute scattering and absorption cross sections of large dielectric particles of arbitrary complex refractive index. The number of internal reflections and transmissions are truncated on the basis of the ratio of the irradiance incident at the nth interface to the irradiance incident at the first interface for a specific optical ray. Thus the truncation number is a function of the angle of incidence. Phase functions for both near- and far-field absorption and scattering of electromagnetic radiation are calculated directly at any desired scattering angle by using a hybrid algorithm based on the bisection and Newton-Raphson methods. With these methods a large sphere's absorption and scattering properties of light can be calculated for any wavelength from the ultraviolet to the microwave regions. Assuming that large snow meltclusters (1-cm order), observed ubiquitously in the snow cover during summer, can be characterized as spheres, one may compute absorption and scattering efficiencies and the scattering phase function on the basis of this geometrical-optics method. A geometrical-optics method for sphere (GOMsphere) code is developed and tested against Wiscombe's Mie scattering code (MIE0) and a Monte Carlo code for a range of size parameters. GOMsphere can be combined with MIE0 to calculate the single-scattering properties of dielectric spheres of any size.

  20. Towards all-dielectric, polarization-independent optical cloaks

    DEFF Research Database (Denmark)

    Andkjær, Jacob Anders; Mortensen, N. Asger; Sigmund, Ole

    2012-01-01

    Fully enclosing, all-dielectric cloaks working for both E-z and H-z polarizations simultaneously are presented in this letter. The cloaks are effective for two antiparallel angles of incidence, and the layout of standard dielectric material in the cloak is determined by topology optimization. Sca...... effectively when distributing a material with lower permittivity than the background material....

  1. On structural, optical and dielectric properties of zinc aluminate ...

    Indian Academy of Sciences (India)

    reports on the dielectric properties of this material is very rarely found in literature. ... C placed on a heating man- ... and dielectric loss of the material using the equation ε = ε tan δ, ..... ble mechanism of a.c. conduction in zinc aluminate particles.

  2. Rectifying the Optical-Field-Induced Current in Dielectrics: Petahertz Diode.

    Science.gov (United States)

    Lee, J D; Yun, Won Seok; Park, Noejung

    2016-02-05

    Investigating a theoretical model of the optical-field-induced current in dielectrics driven by strong few-cycle laser pulses, we propose an asymmetric conducting of the current by forming a heterojunction made of two distinct dielectrics with a low hole mass (m_{h}^{*}≪m_{e}^{*}) and low electron mass (m_{e}^{*}≪m_{h}^{*}), respectively. This proposition introduces the novel concept of a petahertz (10^{15}  Hz) diode to rectify the current in the petahertz domain, which should be a key ingredient for the electric signal manipulation of future light-wave electronics. Further, we suggest the candidate dielectrics for the heterojunction.

  3. Optical design for increased interaction length in a high gradient dielectric laser accelerator

    OpenAIRE

    Cesar, D.; Maxson, J.; Musumeci, P.; Shen, X.; England, R. J.; Wootton, K. P.

    2018-01-01

    We present a methodology for designing and measuring pulse front tilt in an ultrafast laser for use in dielectric laser acceleration. Previous research into dielectric laser accelerating modules has focused on measuring high accelerating gradients in novel structures, but has done so only for short electron-laser coupling lengths. Here we demonstrate an optical design to extend the laser-electron interaction to 1mm.

  4. Dielectric impedance and optical performance of quantum dots doped OLEDs

    Science.gov (United States)

    Jobin, Marc; Pellodi, Cédric; Emmenegger, Nicolas

    2016-04-01

    We investigate the effect of the incorporation of CdSe quantum dots (QD) in the standard ITO/TPD/Alq3/Al organic light emitting diodes (OLED's). The OLED's structures have been prepared in a double glove box coupled to a vacuum chamber containing both low and high temperature evaporators. For the standard (undoped) OLED's, the hole transport layer (HTL) consisting of 50nm of TPD is deposited by spin coating (8000rpm during 60 sec) and the 40nm of Alq3 were deposited at 2A/sec (organic crucible Radak-I). 150nm of Al were finally evaporated at 5A/s. For the CdSe-doped OLED's, the procedure was the same expect that the QD's were mixed with TPD in toluene before spin coating. During the thermal processing if the film, the QD's are expected to segregate to the surface, and then will be located at the TPD/Alq3 interface. The various layers were imaged by Atomic Force Microscopy (AFM) at each phase of the structure deposition, and we could indeed visualize the segregated QD's above the TPD film. AFM was systematically used to monitor the homogeneity and the thickness of the various films. The impedance of the non-encapsulated films structures were measured in air in the 40-40MHz frequency range, with bias at 0V (non-emitting), 2V (low emission) and 8V (strong emission). The corresponding dielectric spectra were analyzed with the standard Havriliak-Negami (HV) formula, where the conductive term has been subtracted from the data in case of light emission. We have measured a relaxation ranging from 100kHZ for the unbiased structure to 1MHz for 8V (strong emission). Apart from this expected relaxation, we found a second relaxation mechanism around 10 MHz. The origin of this second peak will be discussed. To monitor the optical emission of the OLED's, we have built a specific bench which allows for the quantitative measurement of the emission spectra and the dynamics behavior of the OLED's (raising and falling time). We found that the incorporation of the QD's unfortunately

  5. Dielectric and electro-optical parameters of two ferroelectric liquid crystals: a comparative study

    International Nuclear Information System (INIS)

    Kumar Misra, Abhishek; Kumar Srivastava, Abhishek; Shukla, J P; Manohar, Rajiv

    2008-01-01

    Dielectric relaxation and an electro-optical study of two ferroelectric liquid crystals having different spontaneous polarizations (Felix 16/100 and Felix 17/000) showing SmC* and SmA phases have been performed in the temperature range 30-80 compfn C. The experimental data have been used to determine different relaxation parameters, viz. distribution parameter, relaxation frequency, dielectric strength and rotational viscosity. The Goldstone mode of dielectric permittivity has been well observed for both the samples under investigation. The activation energy of both the samples has also been determined by the best theoretical fitting of the Arrhenius plot. We have also evaluated the optical response time and anchoring energy coefficients from electro-optical measurement techniques for these samples.

  6. Structural-optical study of high-dielectric-constant oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Losurdo, M. [Institute of Inorganic Methodologies and Plasmas, IMIP-CNR, Department of Chemistry and INSTM Universita di bari, Via Orabona 4, 70126 Bari (Italy)]. E-mail: maria.losurdo@ba.imip.cnr.it; Giangregorio, M.M. [Institute of Inorganic Methodologies and Plasmas, IMIP-CNR, Department of Chemistry and INSTM Universita di bari, Via Orabona 4, 70126 Bari (Italy); Luchena, M. [Institute of Inorganic Methodologies and Plasmas, IMIP-CNR, Department of Chemistry and INSTM Universita di bari, Via Orabona 4, 70126 Bari (Italy); Capezzuto, P. [Institute of Inorganic Methodologies and Plasmas, IMIP-CNR, Department of Chemistry and INSTM Universita di bari, Via Orabona 4, 70126 Bari (Italy); Bruno, G. [Institute of Inorganic Methodologies and Plasmas, IMIP-CNR, Department of Chemistry and INSTM Universita di bari, Via Orabona 4, 70126 Bari (Italy); Toro, R.G. [Dipartimento di Scienze Chimiche, Universita di Catania, and INSTM-UdR Catania, Viale A. Doria 6, I-95125 Catania (Italy); Malandrino, G. [Dipartimento di Scienze Chimiche, Universita di Catania, and INSTM-UdR Catania, Viale A. Doria 6, I-95125 Catania (Italy); Fragala, I.L. [Dipartimento di Scienze Chimiche, Universita di Catania, and INSTM-UdR Catania, Viale A. Doria 6, I-95125 Catania (Italy); Nigro, R. Lo [Istituto di Microelettronica e Microsistemi, IMM-CNR, Stradale Primosole 50, I-95121 Catania (Italy)

    2006-10-31

    High-k polycrystalline Pr{sub 2}O{sub 3} and amorphous LaAlO{sub 3} oxide thin films deposited on Si(0 0 1) are studied. The microstructure is investigated using X-ray diffraction and scanning electron microscopy. Optical properties are determined in the 0.75-6.5 eV photon energy range using spectroscopic ellipsometry. The polycrystalline Pr{sub 2}O{sub 3} films have an optical gap of 3.86 eV and a dielectric constant of 16-26, which increases with film thickness. Similarly, very thin amorphous LaAlO{sub 3} films have the optical gap of 5.8 eV, and a dielectric constant below 14 which also increases with film thickness. The lower dielectric constant compared to crystalline material is an intrinsic characteristic of amorphous films.

  7. Optical Properties of Metal-Dielectric Structures Based on Photon-Crystal Opal Matrices

    Science.gov (United States)

    Vanin, A. I.; Lukin, A. E.; Romanov, S. G.; Solovyev, V. G.; Khanin, S. D.; Yanikov, M. V.

    2018-04-01

    Optical properties of novel metal-dielectric nanocomposite materials based on opal matrices have been investigated. The position of optical resonances of nanocomposites, obtained by embedding of silver into the opal matrix by the electrothermodiffusion method, is explained by the Bragg diffraction, and an asymmetric form of resonance curves is attributed to the Fano resonance. An anomalous transmission and absorption of light by hybrid plasmon-photonic layered heterostructures, which is apparently associated with excitation of surface plasmon-polaritons, propagating along "metal-dielectric" interfaces, was revealed.

  8. Structural and optical characterization of Cr2O3 nanostructures: Evaluation of its dielectric properties

    International Nuclear Information System (INIS)

    Abdullah, M. M.; Rajab, Fahd M.; Al-Abbas, Saleh M.

    2014-01-01

    The structural, optical and dielectric properties of as-grown Cr 2 O 3 nanostructures are demonstrated in this paper. Powder X-ray diffractometry analysis confirmed the rhombohedral structure of the material with lattice parameter, a = b = 4.953 Å; c = 13.578 Å, and average crystallize size (62.40 ± 21.3) nm. FE-SEM image illustrated the mixture of different shapes (disk, particle and rod) of as-grown nanostructures whereas; EDS spectrum confirmed the elemental purity of the material. FTIR spectroscopy, revealed the characteristic peaks of Cr–O bond stretching vibrations. Energy band gap (3.2 eV) of the nanostructures has been determined using the results of UV-VIS-NIR spectrophotometer. The dielectric properties of the material were checked in the wide frequency region (100Hz-30 MHz). In the low frequency region, the matrix of the dielectric behaves like source as well as sink of electrical energy within the relaxation time. Low value of dielectric loss exhibits that the materials posses good optical quality with lesser defects. The ac conductivity of the material in the high frequency region was found according to frequency power law. The physical-mechanism and the theoretical-interpretation of dielectric-properties of Cr 2 O 3 nanostructures attest the potential candidature of the material as an efficient dielectric medium

  9. Influence of Doping Concentration on Dielectric, Optical, and Morphological Properties of PMMA Thin Films

    Directory of Open Access Journals (Sweden)

    Lyly Nyl Ismail

    2012-01-01

    Full Text Available PMMA thin films were deposited by sol gel spin coating method on ITO substrates. Toluene was used as the solvent to dissolve the PMMA powder. The PMMA concentration was varied from 30 ~ 120 mg. The dielectric properties were measured at frequency of 0 ~ 100 kHz. The dielectric permittivity was in the range of 7.3 to 7.5 which decreased as the PMMA concentration increased. The dielectric loss is in the range of 0.01 ~ –0.01. All samples show dielectric characteristics which have dielectric loss is less than 0.05. The optical properties for thin films were measured at room temperature across 200 ~ 1000 nm wavelength region. All samples are highly transparent. The energy band gaps are in the range of 3.6 eV to 3.9 eV when the PMMA concentration increased. The morphologies of the samples show that all samples are uniform and the surface roughness increased as the concentration increased. From this study, it is known that, the dielectric, optical, and morphology properties were influenced by the amount of PMMA concentration in the solution.

  10. All-dielectric resonant cavity-enabled metals with broadband optical transparency

    Science.gov (United States)

    Liu, Zhengqi; Zhang, Houjiao; Liu, Xiaoshan; Pan, Pingping; Liu, Yi; Tang, Li; Liu, Guiqiang

    2017-06-01

    Metal films with broadband optical transparency are desirable in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and infrared detectors. As bare metal is opaque to light, this issue of transparency attracts great scientific interest. In this work, we proposed and demonstrated a feasible and universal approach for achieving broadband optical transparent (BOT) metals by utilizing all-dielectric resonant cavities. Resonant dielectrics provide optical cavity modes and couple strongly with the surface plasmons of the metal film, and therefore produce a broadband near-unity optical transparent window. The relative enhancement factor (EF) of light transmission exceeds 3400% in comparison with that of pure metal film. Moreover, the transparent metal motif can be realized by other common metals including gold (Au), silver (Ag) and copper (Cu). These optical features together with the fully retained electric and mechanical properties of a natural metal suggest that it will have wide applications in optoelectronic devices.

  11. Effect of oxalic acid on the optical, thermal, dielectric and mechanical behaviour of ADP crystals

    International Nuclear Information System (INIS)

    Rajesh, P.; Ramasamy, P.

    2009-01-01

    The effect of the addition, over a concentration range from 1 to 5 mol%, of oxalic acid on the growth rate, optical transparency, hardness, dielectric behaviour, and SHG efficiency of ammonium dihydrogen phosphate single crystals grown by slow evaporation method has been investigated. UV-Vis studies show that the transparency of the oxalic acid added crystals decreased gradually. Thermal studies indicate that the decomposition temperatures of the crystal are decreased in oxalic acid added ADP crystals. It is observed from the dielectric measurements that the dielectric constant and dielectric loss increase with increase in temperature for all the crystals. Vicker's microhardness study reveals that the addition of higher concentration of oxalic acid decreases the hardness of the crystal. SHG efficiency of 1 mol% of oxalic acid is higher than the pure ADP.

  12. Influence of Zn doping on structural, optical and dielectric properties of LaFeO3

    Science.gov (United States)

    Manzoor, Samiya; Husain, Shahid

    2018-05-01

    The effect of Zn doping on structural, optical and dielectric properties of nano-crystalline LaFe1‑xZnxO3 (0.0 ≤ x ≤ 0.3) samples have been investigated. These samples are synthesized using conventional solid state reaction route. X-ray diffraction patterns with Rietveld analysis confirm the single phase nature of samples. Further, the sample formation has been confirmed by FTIR spectroscopy. All the samples are formed in orthorhombic crystal symmetry with Pbnm space group. The average crystallite sizes, calculated from the Scherer’s formula, lie in the range below 50 nm. Rietveld refinement technique is used to determine lattice parameters, bond lengths and unit cell volume. Williamson-Hall analysis has been performed to calculate the crystallite size and lattice strain. Crystallite sizes are found to be of nanometer range while the strain is of the order of 10‑3. Zn doping leads to the expansion of volume due to the tensile strain. Optical bandgap has been determined from Kubelka-Munk function using Tauc’s relation. Zinc doping in LaFeO3 leads to decrease in optical bandgap. Dielectric constant as a function of frequency is measured in the frequency range of 75 kHz–5 MHz. The dielectric behavior has been investigated by analyzing ‘universal dielectric response’ (UDR) model. The dielectric constant (ε‧) shows colossal value with Zn doping in the whole frequency range. However, the imaginary part (ε″) shows relaxational behavior which may be attributed to the strong correlation that exists between conduction mechanism and dielectric behavior in ferrites. Cole-Cole analysis has been done that confirms the dielectric material does not follow the ideal Debye theory but shows distribution of relaxation times. The a.c conductivity increases with frequency and with Zn doping due to the increased polaron hopping.

  13. Two optical bistability domains in composites of metal nanoparticles with nonlinear dielectric core

    Energy Technology Data Exchange (ETDEWEB)

    Shewamare, Sisay, E-mail: sisayshewa20@yahoo.com [Department of Physics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia); Mal' nev, V.N., E-mail: vadimnmalnev@yahoo.com [Department of Physics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia)

    2012-12-15

    It is shown that the local field in metal spherical particles with a dielectric core in an external varying electric field has two maxima at two different frequencies. The second maximum becomes more important with an increment in the metal fraction. Due to the nonlinear dielectric function of the core, the composite of these inclusions may have two optically induced bistability domains at different frequencies. At rather high metal fraction, two bistability domains merge and form one entire bistability domain. The parameters of these domains are studied numerically. The paper focuses on the second bistability domain, which has not been discussed in the literature so far. This domain exists in a comparatively narrow frequency range and its onset fields are lower than those of the first bistability domain. The lowest bistability onset fields are obtained in the entire domain. This peculiarity of the optical induced bistability in the metal composite with small dielectric cores can be attractive for possible applications.

  14. Two optical bistability domains in composites of metal nanoparticles with nonlinear dielectric core

    International Nuclear Information System (INIS)

    Shewamare, Sisay; Mal'nev, V.N.

    2012-01-01

    It is shown that the local field in metal spherical particles with a dielectric core in an external varying electric field has two maxima at two different frequencies. The second maximum becomes more important with an increment in the metal fraction. Due to the nonlinear dielectric function of the core, the composite of these inclusions may have two optically induced bistability domains at different frequencies. At rather high metal fraction, two bistability domains merge and form one entire bistability domain. The parameters of these domains are studied numerically. The paper focuses on the second bistability domain, which has not been discussed in the literature so far. This domain exists in a comparatively narrow frequency range and its onset fields are lower than those of the first bistability domain. The lowest bistability onset fields are obtained in the entire domain. This peculiarity of the optical induced bistability in the metal composite with small dielectric cores can be attractive for possible applications.

  15. Nonimaging optical concentrators using graded-index dielectric.

    Science.gov (United States)

    Zitelli, M

    2014-04-01

    A new generation of inhomogeneous nonimaging optical concentrators is proposed, able to achieve simultaneously high optical efficiency and acceptance solid angle at a given geometrical concentration factor. General design methods are given, and concentrators are numerically investigated and optimized.

  16. Optical necklaces generated by the diffraction on a stack of dielectric wedges

    Energy Technology Data Exchange (ETDEWEB)

    Izdebskaya, Yana [Nonlinear Physics Centre, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia); Department of Physics, V.I. Vernandsky Taurida National University, Simferopol 95007, Crimea (Ukraine)], E-mail: yvi124@rsphysse.anu.edu.au

    2008-05-19

    We demonstrate that the regular ring-shaped arrays of Gaussian beams, or optical necklaces, can be generated using diffraction on a stack of dielectric wedges. A condition for self-similarity and structural stability of the beams has been derived and shows good comparison with experimental data.

  17. Interrelation between striction forces in dielectrics and optically induced forces in transparent media

    International Nuclear Information System (INIS)

    Torchigin, V P; Torchigin, A V

    2012-01-01

    Optically induced forces applied to a transparent optical medium, which is inserted in a closed plane optical resonator, are calculated by means of an analysis of the changes in the eigenfrequency and energy stored in the resonator at various positions of the medium. These forces are compared with striction forces applied to the medium considered as a dielectric placed in an alternate electrical field within the resonator. It is shown that the optically induced forces are equal to the striction forces. The results of using the classical formula for striction forces in electrostatics are considered. (paper)

  18. Femtosecond laser excitation of dielectric materials: experiments and modeling of optical properties and ablation depths

    DEFF Research Database (Denmark)

    Wædegaard, Kristian Juncher; Frislev, Martin Thomas; Balling, Peter

    2013-01-01

    Modeling of the interaction between a dielec- tric material and ultrashort laser pulses provides the tem- poral evolution of the electronic excitation and the optical properties of the dielectric. Experimentally determined re- flectances and ablation depths for sapphire are compared...... to the calculations. A decrease in reflectance at high fluences is observed experimentally, which demonstrates the neces- sity of a temperature-dependent electron scattering rate in the model. The comparison thus provides new constraints on the optical parameters of the model....

  19. Optical and magnetic properties of new luminescent inorganic materials

    International Nuclear Information System (INIS)

    Acevedo, R; Hurtado, O.F; Poblete, V; Navarro, G

    1999-01-01

    The theoretical and experimental study of radiative and non radiative processes in luminescent inorganic materials is a permanent topic of interest in lineal and non lineal physics. This article aims to present a review and update of the mechanistic aspects associated with spectral intensities in stoichiometric cubic crystals type elpasolite (Cs-2NaLnZ-6), where Ln 3+ is a positive trivalent lanthanide and Z represents a halogen, essentially fluorine, chlorine and bromine, which belong to the spatial Fm3m group. From a theoretical point of view we will be interested in focusing our attention on cutting edge topics such as: the preparation of new models and calculus formalisms for the case of electronic excitations prohibited by parity and electronic spin. We wish to show the set of different complementary and competitive processes that define the relative force values of the electric oscillator and the magnetic one for cubic crystals. We will illustrate our work with a novel system, Cs-2NaEuCI-6, which has theoretical and experimental complexities with unsuspected characteristics

  20. Investigations of structural, dielectric and optical properties on silicon ion irradiated glycine monophosphate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kanagasekaran, T. [Department of Physics, Anna University, Chennai 600 025 (India); Department of Physics and Astrophysics, University of Delhi, New Delhi 110 007 (India); Mythili, P. [Department of Physics, Anna University, Chennai 600 025 (India); Bhagavannarayana, G. [Materials Characterization Division, National Physical Laboratory, New Delhi 110012 (India); Kanjilal, D. [Inter University Accelerator Centre, New Delhi 110 067 (India); Gopalakrishnan, R. [Department of Physics, Anna University, Chennai 600 025 (India)], E-mail: krgkrishnan@annauniv.edu

    2009-08-01

    The 50 MeV silicon ion irradiation induced modifications on structural, optical and dielectric properties of solution grown glycine monophosphate (GMP) crystals were studied. The high-resolution X-ray diffraction study shows the unaltered value of integrated intensity on irradiation. The dielectric constant as a function of frequency and temperature was studied. UV-visible studies reveal the decrease in bandgap values on irradiation and presence of F-centers. The fluorescence spectrum shows the existence of some energy levels, which remains unaffected after irradiation. The scanning electron micrographs reveal the defects formed on irradiation.

  1. Device for simultaneous measurements of the optical and dielectric properties of hydrogels

    International Nuclear Information System (INIS)

    Gómez-Galván, F; Lara-Ceniceros, T; Mercado-Uribe, H

    2012-01-01

    We have designed an experimental device to simultaneously measure the light transmittance and dielectric properties of thermo-sensitive hydrogels. We have used this device to study poly(N-isopropylacrylamide) samples in order to understand the mechanism of water deliverance during the phase transition such hydrogels normally exhibit. We found that the phase transition can be observed dielectrically at low frequencies, when the isothermals obtained during the heating of the samples separate into two groups. The phenomenon occurs due to the increase of ions caused by the dissociation of water molecules released by the polymer, and corresponds to the drop of the optical transmittance

  2. Nanorotors using asymmetric inorganic nanorods in an optical trap

    International Nuclear Information System (INIS)

    Khan, Manas; Sood, A K; Deepak, F L; Rao, C N R

    2006-01-01

    We demonstrate how light force, irrespective of the polarization of the light, can be used to run a simple nanorotor. While the gradient force of a single beam optical trap is used to hold an asymmetric nanorod, we utilize the scattering force to generate a torque on the nanorod, making it rotate about the optic axis. The inherent textural irregularities or morphological asymmetries of the nanorods give rise to the torque under the radiation pressure. Even a small surface irregularity with non-zero chirality is sufficient to produce enough torque for moderate rotational speed. Different sized rotors can be used to set the speed of rotation over a wide range with fine tuning possible through the variation of the laser power. We present a simple dimensional analysis to qualitatively explain the observed trend of the rotational motion of the nanorods

  3. Quantum computer based on activated dielectric nanoparticles selectively interacting with short optical pulses

    International Nuclear Information System (INIS)

    Gadomskii, Oleg N; Kharitonov, Yu Ya

    2004-01-01

    The operation principle of a quantum computer is proposed based on a system of dielectric nanoparticles activated with two-level atoms - cubits, in which electric dipole transitions are excited by short intense optical pulses. It is proved that the logical operation (logical operator) CNOT (controlled NOT) is performed by means of time-dependent transfer of quantum information over 'long' (of the order of 10 4 nm) distances between spherical nanoparticles owing to the delayed interaction between them in the optical radiation field. It is shown that one-cubit and two-cubit logical operators required for quantum calculations can be realised by selectively exciting dielectric particles with short optical pulses. (quantum calculations)

  4. Coupled Optical Tamm States in a Planar Dielectric Mirror Structure Containing a Thin Metal Film

    International Nuclear Information System (INIS)

    Zhou Hai-Chun; Yang Guang; Lu Pei-Xiang; Wang Kai; Long Hua

    2012-01-01

    The coupling between two optical Tamm states (OTSs) with the same eigenenergy is numerically investigated in a planar dielectric mirror structure containing a thin metal film. The reflectivity map in this structure at normal incidence is obtained by applying the transfer matrix method. Two splitting branches appear in the photonic bandgap region when both adjacent dielectric layers of metal film are properly set. The splitting energy of two branches strongly depends on the thickness of the metal film. According to the electric field distribution in this structure, it is found that the high-energy branch corresponds to the antisymmetric coupling between two OTSs, while the low-energy branch is associated with the symmetric coupling between two OTSs. Moreover, the optical difference frequency of two branches is located in a broad terahertz region. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  5. All-optically tunable EIT-like dielectric metasurfaces hybridized with thin phase change material layers

    Science.gov (United States)

    Petronijevic, Emilija; Sibilia, Concita

    2017-05-01

    Electromagnetically induced transparency (EIT), a pump-induced narrow transparency window within the absorption region of a probe, had offered new perspectives in slow-light control in atomic physics. For applications in nanophotonics, the implementation on chip-scaled devices has later been obtained by mimicking this effect by metallic metamaterials. High losses in visible and near infrared range of metal-based metamaterialls have recently opened a new field of all-dielectric metamaterials; a proper configuration of high refractive index dielectric nanoresonators can mimick this effect without losses to get high Q, slow-light response. The next step would be the ability to tune their optical response, and in this work we investigate thin layers of phase change materials (PCM) for all-optical control of EIT-like all-dielectric metamaterials. PCM can be nonvolatively and reversibly switched between two stable phases that differ in optical properties by applying a visible laser pulse. The device is based on Si nanoresonators covered by a thin layer of PCM GeTe; optical and transient thermal simulations have been done to find and optimize the fabrication parameters and switching parameters such as the intensity and duration of the pulse. We have found that the EIT-like response can be switched on and off by applying the 532nm laser pulse to change the phase of the upper GeTe layer. We strongly believe that such approach could open new perspectives in all-optically controlled slow-light metamaterials.

  6. Analytic approach to dielectric optical bent slab waveguides

    Czech Academy of Sciences Publication Activity Database

    Hiremath, K. R.; Hammer, M.; Stoffer, R.; Prkna, Ladislav; Čtyroký, Jiří

    2005-01-01

    Roč. 37, 1/3 (2005), s. 37-61 ISSN 0306-8919 R&D Projects: GA ČR(CZ) GA102/05/0987 Grant - others:European Commission(XE) IST-2000-28018 NAIS Institutional research plan: CEZ:AV0Z20670512 Keywords : integrated optics * optical waveguide theory * modelling Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.688, year: 2005

  7. Porogen residues detection in optical properties of low-k dielectrics cured by ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Marsik, Premysl, E-mail: marsik@physics.muni.c [UFKL, Masaryk University, Kotlarska 2, 61137 Brno (Czech Republic); IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Verdonck, Patrick [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); De Roest, David [ASM Belgium, Kapeldreef 75, 3001 Leuven (Belgium); Baklanov, Mikhail R. [IMEC, Kapeldreef 75, 3001 Leuven (Belgium)

    2010-05-31

    The optical properties of low dielectric constant (low-k) films have been determined by variable angle spectroscopic ellipsometry in the range from 2 eV to 9 eV to characterize the process of porogen removal during the UV-cure. The studied carbon doped oxide (SiCOH) porous dielectric films have been prepared by plasma enhanced chemical vapor deposition. The films have been deposited as a composition of a matrix precursor and an organic porogen. After deposition, the films have been cured by thermal annealing and UV irradiation ({lambda} = 172 nm) to remove the porogen and create a porosity of 33%, reaching a dielectric constant of 2.3. The process of porogen decomposition and removal has been studied on series of low-k samples, UV-cured for various times. Additional samples have been prepared by the deposition and curing of the porogen film, without SiCOH matrix, and the matrix material itself, without porogen. The analysis of the optical response of the porous dielectric as a mixture of matrix material, porogen and voids, together with Fourier transform infrared analysis, allows the sensitive detection of the volume of the porogen and indicates the existence of decomposed porogen residues inside the pores, even for long curing time. The variation of the deposition and curing conditions can control the amount of the porogen residues and the final porosity.

  8. Mechanical, dielectric and optical assessment of glass composites ...

    Indian Academy of Sciences (India)

    The band gap, Urbach energy and the extinction coefficient of the glass composites have been ... icate glasses during our previous studies.7 Lanthanum oxide. (La2O3) .... vs. incident photon energy hν are used to determine the type of optical ...

  9. Structural, optical and dielectric properties of pure and chromium (Cr) doped nickel oxide nanoparticles

    Science.gov (United States)

    Gupta, Jhalak; Ahmed, Arham S.

    2018-05-01

    The pure and Cr doped nickel oxide (NiO) nanoparticles have been synthesized by cost effective co-precipitation method having nickel nitrate as initial precursor. The synthesized samples were characterized by X-Ray diffraction (XRD), UV-Visible Spectroscopy(UV-Vis) and LCR meter for structural, optical and dielectric properties respectively. The crystallite size of pure nickel oxide nanoparticles characterized by XRD using Debye Scherer's formula was found to be 21.7nm and the same decreases on increasing Cr concentration whereas optical and dielectric properties were analyzed by UV-Vis and LCR meter respectively. The energy band gaps were determined by UV-Vis using Tauc relation.

  10. Investigation of optical pump on dielectric tunability in PZT/PT thin film by THz spectroscopy.

    Science.gov (United States)

    Ji, Jie; Luo, Chunya; Rao, Yunkun; Ling, Furi; Yao, Jianquan

    2016-07-11

    The dielectric spectra of single-layer PbTiO3 (PT), single-layer PbZrxTi1-xO3 (PZT) and multilayer PZT/PT thin films under an external optical field were investigated at room temperature by time-domain terahertz (THz) spectroscopy. Results showed that the real part of permittivity increased upon application of an external optical field, which could be interpreted as hardening of the soft mode and increasing of the damping coefficient and oscillator strength. Furthermore, the central mode was observed in the three films. Among the dielectric property of the three thin films studied, the tunability of the PZT/PT superlattice was the largest.

  11. ZnO as dielectric for optically transparent non-volatile memory

    International Nuclear Information System (INIS)

    Salim, N. Tjitra; Aw, K.C.; Gao, W.; Wright, Bryon E.

    2009-01-01

    This paper discusses the application of a DC sputtered ZnO thin film as a dielectric in an optically transparent non-volatile memory. The main motivation for using ZnO as a dielectric is due to its optical transparency and mechanical flexibility. We have established the relationship between the electrical resistivity (ρ) and the activation energy (E a ) of the electron transport in the conduction band of the ZnO film. The ρ of 2 x 10 4 -5 x 10 7 Ω-cm corresponds to E a of 0.36-0.76 eV, respectively. The k-value and optical band-gap for films sputtered with Ar:O 2 ratio of 4:1 are 53 ± 3.6 and 3.23 eV, respectively. In this paper, the basic charge storage element for a non-volatile memory is a triple layer dielectric structure in which a 50 nm thick ZnO film is sandwiched between two layers of methyl silsesquioxane sol-gel dielectric of varying thickness. A pronounced clockwise capacitance-voltage (C-V) hysteresis was observed with a memory window of 6 V. The integration with a solution-processable pentacene, 13,6-N-Sulfinylacetamodipentacene resulted in an optically transparent organic field effect transistor non-volatile memory (OFET-NVM). We have demonstrated that this OFET-NVM can be electrically programmed and erased at low voltage (± 10 V) with a threshold voltage shift of 4.0 V.

  12. Optical Cladding Waveguides in Dielectric Crystals Produced by Femtosecond Laser Inscription

    Directory of Open Access Journals (Sweden)

    Chen Feng

    2013-11-01

    Full Text Available In this work, the recent progress of our research on optical cladding waveguides in dielectric crystals produced by femtosecond laser inscription has been overviewed. With different scales at cross sections, the cladding waveguides support guidance from single mode to highly multi-modes, and work for wavelength till mid-infrared regimes. Applications of the fabricated cladding structures as new integrated light sources are introduced.

  13. Dielectric and optical properties of glasses of CdO-B2O3 system

    International Nuclear Information System (INIS)

    Semin, V.N.; Mal'tsev, V.T.; Panich, A.E.

    1986-01-01

    Dielectric and optical properties of glasses of CdO-B 2 O 3 system are investigated. It is shown, that on changing the composition, cadmic-borate glasses undergo structural changes, similar to those, taking place in lead-borate glasses, and the maximum part of the boron atoms in the oxygen tetrahedral coordination is at CdO:B 2 O 3 =3:2

  14. Biomedical Probes Based on Inorganic Nanoparticles for Electrochemical and Optical Spectroscopy Applications

    Science.gov (United States)

    Yakoh, Abdulhadee; Pinyorospathum, Chanika; Siangproh, Weena; Chailapakul, Orawon

    2015-01-01

    Inorganic nanoparticles usually provide novel and unique physical properties as their size approaches nanometer scale dimensions. The unique physical and optical properties of nanoparticles may lead to applications in a variety of areas, including biomedical detection. Therefore, current research is now increasingly focused on the use of the high surface-to-volume ratios of nanoparticles to fabricate superb chemical- or biosensors for various detection applications. This article highlights various kinds of inorganic nanoparticles, including metal nanoparticles, magnetic nanoparticles, nanocomposites, and semiconductor nanoparticles that can be perceived as useful materials for biomedical probes and points to the outstanding results arising from their use in such probes. The progress in the use of inorganic nanoparticle-based electrochemical, colorimetric and spectrophotometric detection in recent applications, especially bioanalysis, and the main functions of inorganic nanoparticles in detection are reviewed. The article begins with a conceptual discussion of nanoparticles according to types, followed by numerous applications to analytes including biomolecules, disease markers, and pharmaceutical substances. Most of the references cited herein, dating from 2010 to 2015, generally mention one or more of the following characteristics: a low detection limit, good signal amplification and simultaneous detection capabilities. PMID:26343676

  15. Optical response of nanostructured metal/dielectric composites and multilayers

    Science.gov (United States)

    Smith, Geoffrey B.; Maaroof, Abbas I.; Allan, Rodney S.; Schelm, Stefan; Anstis, Geoffrey R.; Cortie, Michael B.

    2004-08-01

    The homogeneous optical response in conducting nanostructured layers, and in insulating layers containing dense arrays of self assembled conducting nanoparticles separated by organic linkers, is examined experimentally through their effective complex indices (n*, k*). Classical effective medium models, modified to account for the 3-phase nanostructure, are shown to explain (n*, k*) in dense particulate systems but not inhomogeneous layers with macroscopic conductance for which a different approach to homogenisation is discussed. (n*, k*) data on thin granular metal films, thin mesoporous gold, and on thin metal layers containing ordered arrays of voids, is linked to properties of the surface plasmon states which span the nanostructured film. Coupling between evanescent waves at either surface counterbalanced by electron scattering losses must be considered. Virtual bound states for resonant photons result, with the associated transit delay leading to a large rise in n* in many nanostructures. Overcoating n-Ag with alumina is shown to alter (n*, k*) through its impact on the SP coupling. In contrast to classical optical homogenisation, effective indices depend on film thickness. Supporting high resolution SEM images are presented.

  16. Optical properties of mesoporous photonic crystals, filled with dielectrics, ferroelectrics and piezoelectrics

    Directory of Open Access Journals (Sweden)

    V. S. Gorelik

    2017-12-01

    Full Text Available At present, it is very important to create new types of mirrors, nonlinear light frequency transformers and optical filters with controlled optical properties. In this connection, it is of great interest to study photonic crystals. Their dielectric permittivity varies periodically in space with a period permitting Bragg diffraction of light. In this paper, we have investigated the optical properties of mesoporous three-dimensional (3D opal-type and one-dimensional (1D anodic alumina photonic crystals, filled with different dielectrics, ferroelectrics and piezoelectrics. We have compared the optical properties of initial mesoporous photonic crystals and filled with different substances. The possibility of mesoporous photonic crystals using selective narrow-band light filters in Raman scattering experiments and nonlinear mirrors has been analyzed. The electromagnetic field enhancing in the case of exciting light frequency close to the stop band edges has been established. The optical harmonics and subharmonics generation in mesoporous crystals, filled with ferroelectrics and piezoelectrics was proposed.

  17. Optical bistability and multistability driven by external magnetic field in a dielectric slab doped with nanodiamond nitrogen vacancy centres

    Science.gov (United States)

    Nasehi, R.; Norouzi, F.

    2016-08-01

    The theoretical investigation of controlling the optical bistability (OB) and optical multistability (OM) in a dielectric medium doped with nanodiamond nitrogen vacancy centres under optical excitation are reported. The shape of the OB curve from dielectric slab can be tuned by changing the external magnetic field and polarization of the control beam. The effect of the intensity of the control laser field and the frequency detuning of probe laser field on the OB and OM behaviour are also discussed in this paper. The results obtained can be used for realizing an all-optical bistable switching or development of nanoelectronic devices.

  18. Optical and microwave dielectric properties of pulsed laser deposited Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Andrews; Goud, J. Pundareekam; Raju, K. C. James [School of Physics, University of Hyderabad, Hyderabad, Telangana 500046 (India); Emani, Sivanagi Reddy [Advanced Center of Research in High Energy Materials (ACRHEM), School of Physics, University of Hyderabad, Telangana 500046 (India)

    2016-05-23

    Optical properties of pulsed laser deposited (PLD) sodium bismuth titanate thin films (NBT), are investigated at wavelengths of 190-2500 nm. Microwave dielectric properties were investigated using the Split Post Dielectric Resonator (SPDR) technique. At 10 GHz, the NBT films have a dielectric constant of 205 and loss tangent of 0.0373 at room temperature. The optical spectra analysis reveals that NBT thin films have an optical band gap E{sub g}=3.55 eV and it has a dielectric constant of 3.37 at 1000 nm with dielectric loss of 0.299. Hence, NBT is a promising candidate for photonic device applications.

  19. Tunable optical response at the plasmon-polariton frequency in dielectric-graphene-metamaterial systems

    Science.gov (United States)

    Calvo-Velasco, D. M.; Porras-Montenegro, N.

    2018-04-01

    By using the scattering matrix formalism, it is studied the optical properties of one dimensional photonic crystals made of multiple layers of dielectric and uniaxial anisotropic single negative electric metamaterial with Drude type responses, with inclusions of graphene in between the dielectric-dielectric interfaces (DGMPC). The transmission spectra for transverse electric (TE) and magnetic (TM) polarization are presented as a function of the incidence angle, the graphene chemical potential, and the metamaterial plasma frequencies. It is found for the TM polarization the tunability of the DGMPC optical response with the graphene chemical potential, which can be observed by means of transmission or reflexion bands around the metamaterial plasmon-polariton frequency, with bandwidths depending on both the incidence angle and the metamaterial plasma frequency. Also, the transmission band is observed when losses in the metamaterial slabs are considered for finite systems. The conditions for the appearance of these bands are shown analytically. We consider this work contributes to open new possibilities to the design of photonic devices with DGMPCs.

  20. Design, Structure, and Optical Properties of Organic-Inorganic Perovskites Containing an Oligothiophene Chromophore.

    Science.gov (United States)

    Mitzi, David B.; Chondroudis, Konstantinos; Kagan, Cherie R.

    1999-12-27

    A quaterthiophene derivative, 5,5' "-bis(aminoethyl)-2,2':5',2' ':5' ',2' "-quaterthiophene (AEQT), has been selected for incorporation within the layered organic-inorganic perovskite structure. In addition to having an appropriate molecular shape and two tethering aminoethyl groups to bond to the inorganic framework, AEQT is also a dye and can influence the optical properties of lead(II) halide-based perovskites. Crystals of C(20)H(22)S(4)N(2)PbBr(4) were grown from a slowly cooled aqueous solution containing lead(II) bromide and quaterthiophene derivative (AEQT.2HBr) salts. The new layered perovskite adopts a monoclinic (C2/c) subcell with the lattice parameters a = 39.741(2) Å, b = 5.8420(3) Å, c = 11.5734(6) Å, beta = 92.360(1) degrees, and Z = 4. Broad superstructure peaks are observed in the X-ray diffraction data, indicative of a poorly ordered, doubled supercell along both the a and b axes. The quaterthiophene segment of AEQT(2+) is nearly planar, with a syn-anti-syn relationship between adjacent thiophene rings. Each quaterthiophene chromophore is ordered between nearest-neighbor lead(II) bromide sheets in a herringbone arrangement with respect to neighboring quaterthiophenes. Room temperature optical absorption spectra for thermally ablated films of the perovskites (AEQT)PbX(4) (X = Cl, Br, I) exhibit an exciton peak arising from the lead(II) halide sheets, along with absorption from the quaterthiophene moiety. No evidence of the inorganic sheet excitonic transition is observed in the photoluminescence spectra for any of the chromophore-containing perovskites. However, strong quaterthiophene photoluminescence is observed for X = Cl, with an emission peak at approximately lambda(max) = 532 nm. Similar photoluminescence is observed for the X = Br and I materials, but with substantial quenching, as the inorganic layer band gap decreases relative to the chromophore HOMO-LUMO gap.

  1. Synthesis and optical properties of novel organic-inorganic hybrid nanolayer structure semiconductors

    International Nuclear Information System (INIS)

    Zhang Sanjun; Lanty, Gaetan; Lauret, Jean-Sebastien; Deleporte, Emmanuelle; Audebert, Pierre; Galmiche, Laurent

    2009-01-01

    We report on the synthesis of some novel organic-inorganic hybrid 2D perovskite semiconductors (R-(CH 2 ) n NH 3 ) 2 PbX 4 . These semiconductors are self-assembled intercalation nanolayers and have a multi-quantum-well energy level structure. We systematically vary the characteristic of organic groups (R-(CH 2 ) n NH 3 + ) to study the relationship between their structures and the optical properties of (R-(CH 2 ) n NH 3 ) 2 PbX 4 . From optical absorption and photoluminescence spectroscopy experiments performed on series of samples, we find some trends of choosing the organic groups to improve the optical performance of (R-(CH 2 ) n NH 3 ) 2 PbX 4 . A new organic group, which allows synthesis of nanolayer perovskite semiconductors with quite high photoluminescence efficiency and better long-term stability, has been found.

  2. Interaction of metallic nanoparticles with dielectric substrates: effect of optical constants

    International Nuclear Information System (INIS)

    Hutter, Tanya; Elliott, Stephen R; Mahajan, Sumeet

    2013-01-01

    In this paper, we study the local-field enhancement in a system of a metallic nanoparticle placed very near to a dielectric substrate. In such systems, intense electric fields are localized in the gap between the particle and the substrate, creating a ‘hot-spot’ under appropriate excitation conditions. We use finite-element numerical simulations in order to study the field enhancement in this dielectric–metal system. More specifically, we show how the optical properties of the dielectric substrate (n and k) affect the plasmonic field enhancement in the nano-gap. We also analyze the degree of field confinement in the gap and discuss it in the context of utilization for surface-enhanced Raman scattering. We finally show the fields generated by real substrates and compare them to metallic ones. (paper)

  3. High-Order Dielectric Metasurfaces for High-Efficiency Polarization Beam Splitters and Optical Vortex Generators

    Science.gov (United States)

    Guo, Zhongyi; Zhu, Lie; Guo, Kai; Shen, Fei; Yin, Zhiping

    2017-08-01

    In this paper, a high-order dielectric metasurface based on silicon nanobrick array is proposed and investigated. By controlling the length and width of the nanobricks, the metasurfaces could supply two different incremental transmission phases for the X-linear-polarized (XLP) and Y-linear-polarized (YLP) light with extremely high efficiency over 88%. Based on the designed metasurface, two polarization beam splitters working in high-order diffraction modes have been designed successfully, which demonstrated a high transmitted efficiency. In addition, we have also designed two vortex-beam generators working in high-order diffraction modes to create vortex beams with the topological charges of 2 and 3. The employment of dielectric metasurfaces operating in high-order diffraction modes could pave the way for a variety of new ultra-efficient optical devices.

  4. Magnetic, electronic, dielectric and optical properties of Pr(Ca:Sr)MnO 3

    Science.gov (United States)

    Sichelschmidt, J.; Paraskevopoulos, M.; Brando, M.; Wehn, R.; Ivannikov, D.; Mayr, F.; Pucher, K.; Hemberger, J.; Pimenov, A.; Krug von Nidda, H.-A.; Lunkenheimer, P.; Ivanov, V. Yu.; Mukhin, A. A.; Balbashov, A. M.; Loidl, A.

    2001-03-01

    The charge-ordered perovskite Pr0.65Ca0.28Sr0.07MnO3 was investigated by means of magnetic susceptibility, specific heat, dielectric and optical spectroscopy and electron-spin resonance techniques. Under moderate magnetic fields, the charge order melts yielding colossal magnetoresistance effects with changes of the resistivity over eleven orders of magnitude. The optical conductivity is studied from audio frequencies far into the visible spectral regime. Below the phonon modes hopping conductivity is detected. Beyond the phonon modes the optical conductivity is explained by polaronic excitations out of a bound state. ESR techniques yield detailed informations on the (H,T ) phase diagram and reveal a broadening of the linewidth which can be modeled in terms of activated polaron hopping.

  5. Femtosecond laser ablation of dielectric materials in the optical breakdown regime: Expansion of a transparent shell

    International Nuclear Information System (INIS)

    Garcia-Lechuga, M.; Siegel, J.; Hernandez-Rueda, J.; Solis, J.

    2014-01-01

    Phase transition pathways of matter upon ablation with ultrashort laser pulses have been considered to be understood long-since for metals and semiconductors. We provide evidence that also certain dielectrics follow the same pathway, even at high pulse energies triggering optical breakdown. Employing femtosecond microscopy, we observe a characteristic ring pattern within the ablating region that dynamically changes for increasing time delays between pump and probe pulse. These transient Newton rings are related to optical interference of the probe beam reflected at the front surface of the ablating layer with the reflection at the interface of the non-ablating substrate. Analysis of the ring structure shows that the ablation mechanism is initiated by a rarefaction wave leading within a few tens of picoseconds to the formation of a transparent thin shell of reduced density and refractive index, featuring optically sharp interfaces. The shell expands and eventually detaches from the solid material at delays of the order of 100 ps.

  6. Femtosecond laser ablation of dielectric materials in the optical breakdown regime: Expansion of a transparent shell

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Lechuga, M.; Siegel, J., E-mail: j.siegel@io.cfmac.csic.es; Hernandez-Rueda, J.; Solis, J. [Laser Processing Group, Instituto de Optica, Serrano 121, 28006 Madrid (Spain)

    2014-09-15

    Phase transition pathways of matter upon ablation with ultrashort laser pulses have been considered to be understood long-since for metals and semiconductors. We provide evidence that also certain dielectrics follow the same pathway, even at high pulse energies triggering optical breakdown. Employing femtosecond microscopy, we observe a characteristic ring pattern within the ablating region that dynamically changes for increasing time delays between pump and probe pulse. These transient Newton rings are related to optical interference of the probe beam reflected at the front surface of the ablating layer with the reflection at the interface of the non-ablating substrate. Analysis of the ring structure shows that the ablation mechanism is initiated by a rarefaction wave leading within a few tens of picoseconds to the formation of a transparent thin shell of reduced density and refractive index, featuring optically sharp interfaces. The shell expands and eventually detaches from the solid material at delays of the order of 100 ps.

  7. Optically-Induced Magnetic Response in All-Dielectric Nanodisk Composite Structures

    Science.gov (United States)

    Chong, Katie Eve

    Optical technologies developed throughout history have been exploiting the electric response in matters in order to control light. However, little has been explored for the magnetic response in matter at optical frequencies due to the lack of magnetic materials in this spectral region. Recently, specially engineered materials, namely metamaterials, have been developed to exploit the magnetic responses in matter for light manipulation. In particular, researchers have made use of the optically-induced magnetic responses (OIMRs) generated in metallic nanostructures to achieve optical effects not seen in nature. Such magnetic responses serve as a second channel to control light, providing an alternative and an addition to the electric responses and leading to novel observations and innovative ideas for light manipulation. This creates many opportunities for the development of the next generation nano-optics and nanophotonic devices. Dielectric nanostructures have recently been discovered to also support OIMR, which is useful for applications requiring low loss and simpler fabrication procedures, such as wavefront control and robust nanoscale sensing. In this thesis, I present the study of OIMR in several all-dielectric systems based on silicon nanodisks, namely single, clusters and regular arrays of nanodisks. The study of these systems provides knowledge for and insight into harnessing the OIMRs in dielectric nanostructures for future applications. Chapter 1 provides a comprehensive introduction to OIMR by presenting a historic overview of the topic and the basic concepts involved for high-index dielectric particles. This is followed by a description of the pioneer works on OIMR in dielectric spherical nanoparticles, including the Mie theory and its recent experimental verification. The similarities and differences between the properties of plasmonic and dielectric nanostructures in the context of metamaterials are also described and explained. Finally, the motivation

  8. Electrical and optical characteristics of dielectric-barrier discharge driven by high voltage nanosecond generator

    International Nuclear Information System (INIS)

    Ahmadeev, V.V.; Kost'yuchenko, S.V.; Kudryavtsev, N.N.; Kurkin, G.A.; Vasilyak, L.M.

    1998-01-01

    Electrical and optical characteristics of the dielectric-barrier discharge in the pressure range of 10-400 Torr were investigated experimentally, particular attention being paid to the discharge homogeneity and to the energy dissipation in the discharge volume. The discharge was driven by a high-voltage pulse generator producing nanosecond high-voltage pulses with an amplitude of 20-30 kV. Air, nitrogen, and helium were used as working gases. The discharge was found to be homogeneous within a wide range of gas pressure. A power density of up to 250 mW/cm 3 has been achieved. (J.U.)

  9. Optical investigation of effective permeability of dilute magnetic dielectrics with magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Ananya, E-mail: banerjee.ananya2008@gmail.com; Sarkar, A. [Dept. of Physics, Bijoy Krishna Girls’ College, 5/3 M.G. Road, Howrah 711101, W.B. (India)

    2016-05-06

    The prime objective of this paper is to investigate the magnetic nature of dilute magnetic dielectrics (DMD) under variation of external magnetic field. The said variation is studied over developed nano-sized Gadolinium Oxide as a DMD system. The observed experimental field variation of the effective magnetic permeability is analyzed results of optical experiment. The experiment records the variation of Brewster angle of incident polarized LASER beam from the surface of developed DMD specimen with applied out of plane external magnetic field. The effective refractive index and hence relative magnetic permeability were estimated following electro-magnetic theory. The overall results obtained and agreement between theory and experiment are good.

  10. Optics of two-stage photovoltaic concentrators with dielectric second stages

    Science.gov (United States)

    Ning, Xiaohui; O'Gallagher, Joseph; Winston, Roland

    1987-04-01

    Two-stage photovoltaic concentrators with Fresnel lenses as primaries and dielectric totally internally reflecting nonimaging concentrators as secondaries are discussed. The general design principles of such two-stage systems are given. Their optical properties are studied and analyzed in detail using computer ray trace procedures. It is found that the two-stage concentrator offers not only a higher concentration or increased acceptance angle, but also a more uniform flux distribution on the photovoltaic cell than the point focusing Fresnel lens alone. Experimental measurements with a two-stage prototype module are presented and compared to the analytical predictions.

  11. Optical investigation of effective permeability of dilute magnetic dielectrics with magnetic field

    Science.gov (United States)

    Banerjee, Ananya; Sarkar, A.

    2016-05-01

    The prime objective of this paper is to investigate the magnetic nature of dilute magnetic dielectrics (DMD) under variation of external magnetic field. The said variation is studied over developed nano-sized Gadolinium Oxide as a DMD system. The observed experimental field variation of the effective magnetic permeability is analyzed results of optical experiment. The experiment records the variation of Brewster angle of incident polarized LASER beam from the surface of developed DMD specimen with applied out of plane external magnetic field. The effective refractive index and hence relative magnetic permeability were estimated following electro-magnetic theory. The overall results obtained and agreement between theory and experiment are good.

  12. Optics of two-stage photovoltaic concentrators with dielectric second stages.

    Science.gov (United States)

    Ning, X; O'Gallagher, J; Winston, R

    1987-04-01

    Two-stage photovoltaic concentrators with Fresnel lenses as primaries and dielectric totally internally reflecting nonimaging concentrators as secondaries are discussed. The general design principles of such two-stage systems are given. Their optical properties are studied and analyzed in detail using computer ray trace procedures. It is found that the two-stage concentrator offers not only a higher concentration or increased acceptance angle, but also a more uniform flux distribution on the photovoltaic cell than the point focusing Fresnel lens alone. Experimental measurements with a two-stage prototype module are presented and compared to the analytical predictions.

  13. SHI induced modification in structural, optical, dielectric and thermal properties of poly ethylene oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Gnansagar B.; Bhavsar, Shilpa [Department of Physics, The M.S. University of Baroda, Vadodara 390002 (India); Singh, N.L., E-mail: nl.singh-phy@msubaroda.ac.in [Department of Physics, The M.S. University of Baroda, Vadodara 390002 (India); Singh, F.; Kulriya, P.K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2016-07-15

    Poly ethylene oxide (PEO) films were synthesized by solution cast method. These self-standing films were exposed with 60 MeV C{sup +5} ion and 100 MeV Ni{sup +7} ion at different fluences. SHI induced effect was investigated by employing various techniques. The crystalline size decreased upon irradiation as observed from XRD analysis. FTIR analysis reveals the decrement in the peak intensity upon irradiation. Tauc’s method was used to determine the optical band gap (E{sub g}), which shows decreasing trends with increase of fluence. The dielectric properties were investigated in the frequency range 10 Hz to 10 MHz for unirradiated and irradiated films. The dielectric constant remains same for the broad-spectrum of frequency and increases at lower frequency. The dielectric loss also moderately influence as a function of frequency due to irradiation. DSC analysis validated the results of XRD. Scanning electron microscopy (SEM) reveals that there is significant change in the surface morphology due to irradiation.

  14. Development of hybrid organic-inorganic optical coatings to prevent laser damage

    International Nuclear Information System (INIS)

    Compoint, Francois

    2015-01-01

    The optical devices (lents, mirrors, portholes...) that are set on the chains of the Laser Megajoule (LMJ) may be damaged by the high energy laser beam especially around the UV wavelength of 351 nm. The damages are micronic craters on the rear of the optics that grows exponentially after each laser shots. The study aims at developing some optical thin coatings on the rear of the optical substrates to prevent the growth of the damage by amortizing the laser shock wave, self-healing the craters that has appeared, or repairing the laser hole after the damage occurs. The thin coatings have been prepared by a sol-gel method by using silica precursor and a polydimethylsiloxane (PDMS) elastomer. The two species reacted together to get a hybrid organic-inorganic Ormosil (organically modified silica) material, by creating a silica network linked to the PDMS species with covalent and hydrogen bounds. The thin layers are obtained from the sol-gel solution by using a dip and spin coating method. The coatings have an excellent optical transmission around the UV (351 nm) wavelength. They also have some self-healing properties by using mechanical (viscoelastic) mechanism and chemical reversible hydrogen bounds action in the materials. The silica-PDMS coatings prove to be resistant to the laser beam at 351 nm, despite some optimizations that still need to be done to reach the sought laser damage threshold. (author) [fr

  15. Equilateral Triangular Dielectric Resonator Nantenna at Optical Frequencies for Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Waleed Tariq Sethi

    2015-01-01

    Full Text Available The last decade has witnessed a remarkable growth in the telecommunication industry. With the introduction of smart gadgets, the demand for high data rate and bandwidth for wireless applications have increased exponentially at the cost of exponential consumption of energy. The latter is pushing the research and industry communities to devise green communication solutions that require the design of energy saving devices and techniques in one part and ambient energy harvesting techniques in the other part. With the advent of nanocomponents fabrication technology, researchers are now able to tap into the THz frequency regime and fabricate optical low profile antennas at a nanoscale. Optical antennas have proved their potential and are revolutionizing a class of novel optical detectors, interconnectors, sensors, and energy harvesting related fields. Authors in this paper propose an equilateral triangular dielectric resonator nantenna (ETDRNA working at 193.5 THz standard optical frequency. The simulated antenna achieves an impedance bandwidth from 192.3 THz to 197.3 THz with an end-fire directivity of 8.6 dBi, covering the entire standard optical window of C-band. Numerical demonstrations prove the efficiency of the nantenna at the frequencies of interest, making it a viable candidate for future green energy harvesting and high speed optical applications.

  16. Electronic, structural, and optical properties of host materials for inorganic phosphors

    International Nuclear Information System (INIS)

    Alemany, Pere; Moreira, Ibério de P.R.; Castillo, Rodrigo; Llanos, Jaime

    2012-01-01

    Highlights: ► We performed a first-principles DFT study of the electronic structures of several wide band gap insulators (La 2 O 3 , La 2 O 2 S, Y 2 O 3 Y 2 O 2 S, La 2 TeO 6 , and Y 2 TeO 6 ) used as host materials for inorganic phosphors. ► The electronic, structural, and optical properties calculated for these compounds are in good agreement with the available experimental data. ► The electronic structure of the M 2 TeO 6 phases exhibits distinct features that could allow a fine tuning of the optical properties of luminescent materials obtained by doping with rare earth metals. - Abstract: A family of large gap insulators used as host materials for inorganic phosphors (La 2 O 3 , La 2 O 2 S, Y 2 O 3 , Y 2 O 2 S, La 2 TeO 6 , and Y 2 TeO 6 ) have been studied by first-principles DFT based calculations. We have determined electronic, structural, and optical properties for all these compounds both at the LDA and GGA levels obtaining, in general, a good agreement with available experimental data and previous theoretical studies. The electronic structure for the M 2 TeO 6 phases, addressed in this work for the first time, reveals some significant differences with respect to the other compounds, especially in the region of the lower conduction band, where the appearance of a group of four isolated oxygen/tellurium based bands below the main part of the La (Y) centered conduction band is predicted to lead to significant changes in the optical properties of the two tellurium containing compounds with respect to the rest of compounds in the series.

  17. Structural, optical, dielectric and magnetic studies of gadolinium-added Mn-Cu nanoferrites

    Science.gov (United States)

    Kanna, R. Rajesh; Lenin, N.; Sakthipandi, K.; Kumar, A. Senthil

    2018-05-01

    Spinel ferrite with the general formula Mn1-xCuxFe1.85Gd0.15O4 (x = 0.2, 0.4, 0.6 and 0.8) was synthesized using the standard sonochemical method. The structure, optical, morphology, dielectric and magnetic properties of the prepared Mn1-xCuxFe1.85Gd0.15O4 nanoferrites were exhaustively investigated using various characterization techniques. The phase purity, secondary phase and crystallite parameters were studied from X-ray diffraction patterns. Fourier transform infrared spectra showed two absorption bands of transition metal oxides in the frequency range from 400 to 650 cm-1, which are related to asymmetric stretching modes of the spinel ferrites (AB2O4). Raman spectra have five active modes illustrating the vibration of O2- ions at both tetrahedral (A) site and octahedral (B) site ions. The wide and narrow scan spectrum from X-ray photoelectron spectroscopy results confirmed the presence of Mn, Cu, Gd, Fe, C and O elements in the composition. The oxidation state and core level of the photo electron peaks of Mn 2p, Cu 2p, Gd 3d, Fe 2p and O 1s were analyzed. The influence of the Cu2+ concentration in Mn1-xCuxFe1.85Gd0.15O4 on the morphology, varying from nanorods, nanoflakes to spherical, was explored on the basis of scanning electron microscopy images. Ultraviolet diffuse reflectance spectroscopy studies indicated that the optical bandgap (5.12-5.32 eV) of the nanoferrites showed an insulating behavior. The dielectric constant, loss tangent and complex dielectric constant values decreased with an increase in frequency with the addition of Gd3+ content. A vibrating sample magnetometer showed that the prepared nanoferrites had a soft ferromagnetic nature. The magnetic parameter changed markedly with an increase in the Cu content in Mn1-xCuxFe1.85Gd0.15O4 nanoferrites. The optical, dielectric and magnetic properties were considerably enhanced with the addition of Gd3+ ions in the spinel nanoferrites.

  18. Optical pulling force on a magneto-dielectric Rayleigh sphere in Bessel tractor polarized beams

    International Nuclear Information System (INIS)

    Mitri, F.G.; Li, R.X.; Yang, R.P.; Guo, L.X.; Ding, C.Y.

    2016-01-01

    The optical radiation force induced by Bessel (vortex) beams on a magneto-dielectric subwavelength sphere is investigated with particular emphasis on the beam polarization and order l (or topological charge). The analysis is focused on identifying the regions and some of the conditions to achieve retrograde motion of the sphere centered on the axis of wave propagation of the incident beam, or shifted off-axially. Exact non-paraxial analytical solutions are established, and computations for linear, circular, radial, azimuthal and mixed polarizations of the individual plane wave components forming the Bessel (vortex) beams by means of the angular spectrum decomposition method (ASDM) illustrate the theory with particular emphasis on the tractor (i.e. reversal) behavior of the force. This effect results in the pulling of the magneto-dielectric sphere against the forward linear momentum density flux associated with the incoming waves. Should some conditions related to the choice of the beam parameters as well as the permittivity and permeability of the sphere be met, the optical force vanishes and reverses sign. Moreover, the beam polarization is shown to affect differently the axial negative pulling force for either the zeroth- or the first-order Bessel beam. When the sphere is centered on the beam′s axis, the axial force component is always negative for the zeroth-order Bessel beam except for the radial and azimuthal polarization configurations. Nonetheless, for the first-order Bessel beam, the axial force is negative for the radial polarization case only. Additional tractor beam effects arise when the sphere departs from the center of the beam. It is also demonstrated that the tractor beam effect arises from the force component originating from the cross-interaction between the electric and magnetic dipoles. Potential applications are in particle manipulation, optical levitation, tractor beam tweezers, and other emergent technologies using polarized Bessel beams on

  19. Ultrafast nonlinear optical processes in metal-dielectric nanocomposites and nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwang-Hyon

    2012-04-13

    This work reports results of a theoretical study of nonlinear optical processes in metal-dielectric nanocomposites used for the increase of the nonlinear coefficients and for plasmonic field enhancement. The main results include the study of the transient saturable nonlinearity in dielectric composites doped with metal nanoparticles, its physical mechanism as well its applications in nonlinear optics. For the study of the transient response, a time-depending equation for the dielectric function of the nanocomposite using the semi-classical two-temperature model is derived. By using this approach, we study the transient nonlinear characteristics of these materials in comparison with preceding experimental measurements. The results show that these materials behave as efficient saturable absorbers for passive mode-locking of lasers in the spectral range from the visible to near IR. We present results for the modelocked dynamics in short-wavelength solid-state and semiconductor disk lasers; in this spectral range other efficient saturable absorbers do not exist. We suggest a new mechanism for the realization of slow light phenomenon by using glasses doped with metal nanoparticles in a pump-probe regime near the plasmonic resonance. Furthermore, we study femtosecond plasmon generation by mode-locked surface plasmon polariton lasers with Bragg reflectors and metal-gain-absorber layered structures. In the final part of the thesis, we present results for high-order harmonic generation near a metallic fractal rough surface. The results show a possible reduction of the pump intensities by three orders of magnitudes and two orders of magnitudes higher efficiency compared with preceding experimental results by using bow-tie nanostructures.

  20. Enhanced optical-to-THz conversion efficiency of photoconductive antenna using dielectric nano-layer encapsulation

    Science.gov (United States)

    Gupta, Abhishek; Rana, Goutam; Bhattacharya, Arkabrata; Singh, Abhishek; Jain, Ravikumar; Bapat, Rudheer D.; Duttagupta, S. P.; Prabhu, S. S.

    2018-05-01

    Photoconductive antennas (PCAs) are among the most conventional devices used for emission as well as detection of terahertz (THz) radiation. However, due to their low optical-to-THz conversion efficiencies, applications of these devices in out-of-laboratory conditions are limited. In this paper, we report several factors of enhancement in THz emission efficiency from conventional PCAs by coating a nano-layer of dielectric (TiO2) on the active area between the electrodes of a semi-insulating GaAs-based device. Extensive experiments were done to show the effect of thicknesses of the TiO2 layer on the THz power enhancement with different applied optical power and bias voltages. Multiphysics simulations were performed to elucidate the underlying physics behind the enhancement of efficiency of the PCA. Additionally, this layer increases the robustness of the electrode gaps of the PCAs with high electrical insulation as well as protect it from external dust particles.

  1. Improved longitudinal magneto-optic Kerr effect signal contrast from nanomagnets with dielectric coatings

    Science.gov (United States)

    Holiday, L. F.; Gibson, U. J.

    2006-12-01

    We report on the use of dielectric coatings to improve the contrast of longitudinal magneto-optic Kerr effect signals from submicron magnetic structures. Electron-beam lithography was used to define disks in 22 nm thick Ni films deposited on Si substrates. The structures were measured in four configurations: as-deposited, through a fused silica prism using index-matching fluid, coated with ZnS, and using a prism on top of the ZnS layer. The modified samples show up to 20 times improvement in the MOKE contrast due to admittance matching to the magnetic material and suppression of the substrate reflectance. The behavior is successfully predicted by a model that includes the magneto-optic response of the nickel layer and accounts for the fraction of the beam intercepted by the magnetic structure.

  2. A simple model for fibre optics: planar dielectric waveguides in rotation

    International Nuclear Information System (INIS)

    Perez-Ocon, F; Pena, A; Jimenez, J R; Diaz, J A

    2006-01-01

    In planar dielectric waveguides, there is only one type of propagated ray: the one that crosses the waveguide axis after each total internal reflection. According to the model of geometrical optics, there are two types of guided ray in fibre optics: meridional and skew. Each one is formulated by a suitable mathematical treatment. In this work, we demonstrate that the complex mathematical treatment for the skew rays can be avoided by considering a planar waveguide (with the same refractive index profile as the fibre and thickness equal to its diameter) that rotates around the direction of the axis with angular velocity ω. A section of this fibre is inscribed in the hypothetical slab. This model has been successfully introduced to students of engineering and physics

  3. The optical properties of transferred graphene and the dielectrics grown on it obtained by ellipsometry

    Science.gov (United States)

    Kasikov, Aarne; Kahro, Tauno; Matisen, Leonard; Kodu, Margus; Tarre, Aivar; Seemen, Helina; Alles, Harry

    2018-04-01

    Graphene layers grown by chemical vapour deposition (CVD) method and transferred from Cu-foils to the oxidized Si-substrates were investigated by spectroscopic ellipsometry (SE), Raman and X-Ray Photoelectron Spectroscopy (XPS) methods. The optical properties of transferred CVD graphene layers do not always correspond to the ones of the exfoliated graphene due to the contamination from the chemicals used in the transfer process. However, the real thickness and the mean properties of the transferred CVD graphene layers can be found using ellipsometry if a real thickness of the SiO2 layer is taken into account. The pulsed laser deposition (PLD) and atomic layer deposition (ALD) methods were used to grow dielectric layers on the transferred graphene and the obtained structures were characterized using optical methods. The approach demonstrated in this work could be useful for the characterization of various materials grown on graphene.

  4. ASYMPTOTICAL CALCULATION OF ELECTROMAGNETIC WAVES SCATTERED FROM A DIELECTRIC COATED CYLINDRICAL SURFACE WITH PHYSICAL OPTICS APPROACH

    Directory of Open Access Journals (Sweden)

    Uğur YALÇIN

    2004-02-01

    Full Text Available In this study, quasi-optical scattering of finite source electromagnetic waves from a dielectric coated cylindrical surface is analysed with Physical Optics (PO approach. A linear electrical current source is chosen as the finite source. Reflection coefficient of the cylindrical surface is derived by using Geometrical Theory of Diffraction (GTD. Then, with the help of this coefficient, fields scattered from the surface are obtained. These field expressions are used in PO approach and surface scattering integral is determined. Evaluating this integral asymptotically, fields reflected from the surface and surface divergence coefficient are calculated. Finally, results obtained in this study are evaluated numerically and effects of the surface impedance to scattered fields are analysed. The time factor is taken as j te? in this study.

  5. Symposium KK, Resonant Optics in Dielectric and Metallic Structures: Fundamentals and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Larouche, Stephane [Duke Univ., Durham, NC (United States); Caldwell, Joshua [Naval Research Lab. (NRL), Washington, DC (United States)

    2016-09-06

    Symposium KK focused on the design, fabrication, characterization of novel nanoscale optical resonators and alternative materials for sub-diffraction scale resonant particles. Contributions discussed all aspects of this field, and the organizers had more than 130 contributing participants to this session alone, spanning North America, Europe, Asia and Australia. Participants discussed cutting edge research results focused on the structure, physical and optical properties, and ultrafast dynamic response of nanoscale resonators such as plasmonic and dielectric nanoparticles. A strong focus on state-of-the-art characterization and fabrication approaches, as well as presentations on novel materials for sub-diffraction resonators took place. As expected, the sessions provided strong interdisciplinary interactions and lively debate among presenters and participants.

  6. Optical and dielectric properties of neutron irradiated MgAl2O4 spinels

    International Nuclear Information System (INIS)

    Ibarra, A.

    1996-01-01

    The radiation effects on the optical and electrical properties of stoichiometric MgAl 2 O 4 spinel specimens irradiated in FFTF-MOTA at temperatures between 385 and 750 C to fluence ranging from 5.3 to 24.9 x 10 26 n m -2 (E>0.1 McV) are measured. In the optical properties a strong absorption in the ultraviolet range is observed together with a small band around 20 000 cm -1 (510 nm). Two strong luminescence emissions are also observed around 700 nm, with excitation spectra in the ultraviolet region. In the electrical properties a strong decrease of conductivity is observed in the temperature range from 0 to 500 C. Other techniques (like dielectric spectroscopy and EPR) have been used. (orig.)

  7. Analysis of specular resonance in dielectric bispheres using rigorous and geometrical-optics theories.

    Science.gov (United States)

    Miyazaki, Hideki T; Miyazaki, Hiroshi; Miyano, Kenjiro

    2003-09-01

    We have recently identified the resonant scattering from dielectric bispheres in the specular direction, which has long been known as the specular resonance, to be a type of rainbow (a caustic) and a general phenomenon for bispheres. We discuss the details of the specular resonance on the basis of systematic calculations. In addition to the rigorous theory, which precisely describes the scattering even in the resonance regime, the ray-tracing method, which gives the scattering in the geometrical-optics limit, is used. Specular resonance is explicitly defined as strong scattering in the direction of the specular reflection from the symmetrical axis of the bisphere whose intensity exceeds that of the scattering from noninteracting bispheres. Then the range of parameters for computing a particular specular resonance is specified. This resonance becomes prominent in a wide range of refractive indices (from 1.2 to 2.2) in a wide range of size parameters (from five to infinity) and for an arbitrarily polarized light incident within an angle of 40 degrees to the symmetrical axis. This particular scattering can stay evident even when the spheres are not in contact or the sizes of the spheres are different. Thus specular resonance is a common and robust phenomenon in dielectric bispheres. Furthermore, we demonstrate that various characteristic features in the scattering from bispheres can be explained successfully by using intuitive and simple representations. Most of the significant scatterings other than the specular resonance are also understandable as caustics in geometrical-optics theory. The specular resonance becomes striking at the smallest size parameter among these caustics because its optical trajectory is composed of only the refractions at the surfaces and has an exceptionally large intensity. However, some characteristics are not accounted for by geometrical optics. In particular, the oscillatory behaviors of their scattering intensity are well described by

  8. Imaging optical fields below metal films and metal-dielectric waveguides by a scanning microscope

    Science.gov (United States)

    Zhu, Liangfu; Wang, Yong; Zhang, Douguo; Wang, Ruxue; Qiu, Dong; Wang, Pei; Ming, Hai; Badugu, Ramachandram; Rosenfeld, Mary; Lakowicz, Joseph R.

    2017-09-01

    Laser scanning confocal fluorescence microscopy (LSCM) is now an important method for tissue and cell imaging when the samples are located on the surfaces of glass slides. In the past decade, there has been extensive development of nano-optical structures that display unique effects on incident and transmitted light, which will be used with novel configurations for medical and consumer products. For these applications, it is necessary to characterize the light distribution within short distances from the structures for efficient detection and elimination of bulky optical components. These devices will minimize or possibly eliminate the need for free-space light propagation outside of the device itself. We describe the use of the scanning function of a LSCM to obtain 3D images of the light intensities below the surface of nano-optical structures. More specifically, we image the spatial distributions inside the substrate of fluorescence emission coupled to waveguide modes after it leaks through thin metal films or dielectric-coated metal films. The observed spatial distribution were in general agreement with far-field calculations, but the scanning images also revealed light intensities at angles not observed with classical back focal plane imaging. Knowledge of the subsurface optical intensities will be crucial in the combination of nano-optical structures with rapidly evolving imaging detectors.

  9. The all-optical modulator in dielectric-loaded waveguide with graphene-silicon heterojunction structure

    Science.gov (United States)

    Sun, Feiying; Xia, Liangping; Nie, Changbin; Shen, Jun; Zou, Yixuan; Cheng, Guiyu; Wu, Hao; Zhang, Yong; Wei, Dongshan; Yin, Shaoyun; Du, Chunlei

    2018-04-01

    All-optical modulators based on graphene show great promise for on-chip optical interconnects. However, the modulation performance of all-optical modulators is usually based on the interaction between graphene and the fiber, limiting their potential in high integration. Based on this point, an all-optical modulator in a dielectric-loaded waveguide (DLW) with a graphene-silicon heterojunction structure (GSH) is proposed. The DLW raises the waveguide mode, which provides a strong light-graphene interaction. Sufficient tuning of the graphene Fermi energy beyond the Pauli blocking effect is obtained with the presented GSH structure. Under the modulation light with a wavelength of 532 nm and a power of 60 mW, a modulation efficiency of 0.0275 dB µm-1 is achieved for light with a communication wavelength of 1.55 µm in the experiment. This modulator has the advantage of having a compact footprint, which may make it a candidate for achieving a highly integrated all-optical modulator.

  10. Theory of tailorable optical response of two-dimensional arrays of plasmonic nanoparticles at dielectric interfaces.

    Science.gov (United States)

    Sikdar, Debabrata; Kornyshev, Alexei A

    2016-09-22

    Two-dimensional arrays of plasmonic nanoparticles at interfaces are promising candidates for novel optical metamaterials. Such systems materialise from 'top-down' patterning or 'bottom-up' self-assembly of nanoparticles at liquid/liquid or liquid/solid interfaces. Here, we present a comprehensive analysis of an extended effective quasi-static four-layer-stack model for the description of plasmon-resonance-enhanced optical responses of such systems. We investigate in detail the effects of the size of nanoparticles, average interparticle separation, dielectric constants of the media constituting the interface, and the nanoparticle position relative to the interface. Interesting interplays of these different factors are explored first for normally incident light. For off-normal incidence, the strong effects of the polarisation of light are found at large incident angles, which allows to dynamically tune the reflectance spectra. All the predictions of the theory are tested against full-wave simulations, proving this simplistic model to be adequate within the quasi-static limit. The model takes seconds to calculate the system's optical response and makes it easy to unravel the effect of each system parameter. This helps rapid rationalization of experimental data and understanding of the optical signals from these novel 'metamaterials', optimised for light reflection or harvesting.

  11. Enhancing Optically Pumped Organic-Inorganic Hybrid Perovskite Amplified Spontaneous Emission via Compound Surface Plasmon Resonance

    Directory of Open Access Journals (Sweden)

    Xiaoyan Wu

    2018-03-01

    Full Text Available Organic-inorganic hybrid perovskite has attracted intensive attention from researchers as the gain medium in lasing devices. However, achieving electrically driven lasing remains a significant challenge. Modifying the devices’ structure to enhance the optically pumped amplified spontaneous emission (ASE is the key issue. In this work, gold nanoparticles (Au NPs are first doped into PEDOT: PSS buffer layer in a slab waveguide device structure: Quartz/PEDOT: PSS (with or w/o Au NPs/CH3NH3PbBr3. As a result, the facile device shows a significantly enhanced ASE intensity and a narrowed full width at half maximum. Based on experiments and theoretical simulation data, the improvement is mainly a result of the compound surface plasmon resonance, including simultaneous near- and far-field effects, both of which could increase the density of excitons excited state and accelerate the radiative decay process. This method is highly significant for the design and development and fabrication of high-performance organic-inorganic hybrid perovskite lasing diodes.

  12. Synthesis and optical properties of novel organic-inorganic hybrid nanolayer structure semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Sanjun; Lanty, Gaetan; Lauret, Jean-Sebastien [Laboratoire de Photonique Quantique et Moleculaire de l' Ecole Normale Superieure de Cachan, 61 avenue du President Wilson, 94235 Cachan (France); Deleporte, Emmanuelle, E-mail: Emmanuelle.Deleporte@lpqm.ens-cachan.fr [Laboratoire de Photonique Quantique et Moleculaire de l' Ecole Normale Superieure de Cachan, 61 avenue du President Wilson, 94235 Cachan (France); Audebert, Pierre; Galmiche, Laurent [Laboratoire de Photophysique et Photochimie Supramoleculaires et Macromoleculaires de l' Ecole Normale Superieure de Cachan, 61 avenue du President Wilson, 94235 Cachan (France)

    2009-06-15

    We report on the synthesis of some novel organic-inorganic hybrid 2D perovskite semiconductors (R-(CH{sub 2}){sub n}NH{sub 3}){sub 2}PbX{sub 4}. These semiconductors are self-assembled intercalation nanolayers and have a multi-quantum-well energy level structure. We systematically vary the characteristic of organic groups (R-(CH{sub 2}){sub n}NH{sub 3}{sup +}) to study the relationship between their structures and the optical properties of (R-(CH{sub 2}){sub n}NH{sub 3}){sub 2}PbX{sub 4}. From optical absorption and photoluminescence spectroscopy experiments performed on series of samples, we find some trends of choosing the organic groups to improve the optical performance of (R-(CH{sub 2}){sub n}NH{sub 3}){sub 2}PbX{sub 4}. A new organic group, which allows synthesis of nanolayer perovskite semiconductors with quite high photoluminescence efficiency and better long-term stability, has been found.

  13. Synthesis, crystal structure and growth of a new inorganic- organic hybrid compound for nonlinear optical applications: Aquadiiodo (3-aminopropanoic acid) cadmium (II)

    Science.gov (United States)

    Boopathi, K.; Babu, S. Moorthy; Jagan, R.; Ramasamy, P.

    2017-12-01

    The new inorganic-organic hybrid material aquadiiodo (3-aminopropanoic acid) cadmium (II) [ADI (3-AP) Cd] has been successfully synthesized and good quality crystals have been grown by slow evaporation solution technique. The structure was determined by single crystal X-ray diffraction at room temperature. The compound crystallizes in monoclinic crystal system with centro symmetric space group P21/c and four molecules in the unit cell. The structure of the title compound was further confirmed by 1H and 13C nuclear magnetic resonance spectral analysis. FT-IR spectroscopy was used to confirm the presence of various functional groups in the compound. The transmittance and optical parameters of the crystal were studied by UV- Visible-NIR spectroscopy. The thermal stability of the grown crystal was evaluated using thermogravimetric and differential thermal analyses. Mechanical hardness has been identified by Vickers micro hardness study and work hardening coefficient was calculated. Dielectric measurement was carried out as a function of frequency and results are discussed. The growth mechanism of the crystal was assessed by chemical etching studies. The third-order nonlinear optical susceptibility of [ADI (3-AP) Cd] was derived using the Z-scan technique, and it was 3.24955 × 10-8 esu. The positive nonlinear refractive index 2.48505 × 10-11 m2/W, is an indication of self-defocusing optical nonlinearity of the sample. It is believed that the [ADI (3-AP) Cd] is a promising new candidate for developing efficient nonlinear optical and optical power limiting devices.

  14. [Study on formation process of honeycomb pattern in dielectric barrier discharge by optical emission spectrum].

    Science.gov (United States)

    Dong, Li-Fang; Zhu, Ping; Yang, Jing; Zhang, Yu

    2014-04-01

    The authors report on the first investigation of the variations in the plasma parameters in the formation process of the honeycomb pattern in a dielectric barrier discharge by optical emission spectrum in argon and air mixture. The discharge undergoes hexagonal lattice, concentric spot-ring pattern and honeycomb pattern with the applied voltage increasing. The molecular vibration temperature, electron excitation temperature and electronic density of the three kinds of patterns were investigated by the emission spectra of nitrogen band of second positive system (C3pi(u) --> B3 pi(g)), the relative intensity ratio method of spectral lines of Ar I 763.51 nm (2P(6) --> 1S(5)) and Ar I 772.42 nm (2P(2) -->1S(3)) and the broadening of spectral line 696.5 nm respectively. It was found that the molecular vibration temperature and electron excitation temperature of the honeycomb pattern are higher than those of the hexagonal lattice, but the electron density of the former is lower than that of the latter. The discharge powers of the patterns were also measured with the capacitance method. The discharge power of the honeycomb pattern is much higher than that of the hexagonal lattice. These results are of great importance to the formation mechanism of the patterns in dielectric barrier discharge.

  15. Structural characterization, vibrational spectroscopy accomplished with DFT calculation, thermal and dielectric behaviors in a new organic-inorganic tertrapropylammonium aquapentachlorostannate dihydrate compound

    Energy Technology Data Exchange (ETDEWEB)

    Hajlaoui, Sondes, E-mail: hajlaouisondes@yahoo.fr [Unité de recherche de la matière condensée, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax (Tunisia); Chaabane, Iskandar [Unité de recherche de la matière condensée, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax (Tunisia); Lhoste, Jérôme; Bulou, Alain [LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et Matériaux du Mans (IMMM), Avenue Olivier Messiaen, 72085, Le Mans, Cedex 9 (France); Guidara, Kamel [Unité de recherche de la matière condensée, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax (Tunisia)

    2016-09-15

    In this work a novel compound tertrapropylammonium aquapentachlorostannate dihydrate was synthesized and characterized by; single crystal X-ray diffraction, vibrational spectroscopy, differential scanning calorimetric and dielectric measurement. The crystal structure refinement at room temperature reveled that this later belongs to the monoclinic compound with P121/c1 space group with the following unit cell parameters a = 8.2699(3) Å, b = 12.4665(4) Å, c = 22.3341(7) Å and β = 92.94(0)°. The crystal arrangement can be described by stacked organic-inorganic layers in the c direction with two independent water molecules placed between each two layers. The detailed interpretations of the vibrational properties of the studied compound were performed using density functional theory (DFT) with the B3LYP/LanL2DZ basis set, and has enabled us to make the detailed assignments by comparative study of the experimental and calculated Raman and IR spectra. The differential scanning calorimetry (DSC) measurement disclosed two anomalies in the temperature range 356–376 (T{sub 1}) K and at 393 K (T{sub 2}) characterized by the dehydration of the sample and probably a reconstruction of a new structure after T{sub 2} transition. The temperature dependences of dielectric permittivity show a relaxation process around T{sub 2} anomaly indicating the occurrence of the disorder at high temperature. The dependence of the exponent m(T) on temperature, extracted from the straight lines of log(ε″) with log (ω), suggests that the correlated barrier hopping is the appropriate model for the conduction mechanism. - Highlights: • The single-crystal X-ray diffraction has been performed. • The assignments of the vibration modes based on DFT were reported and discussed. • Differential scanning calorimetric reveals the presence of two endothermic peaks. • The electric permittivity was studied using the impedance measurements. • The CBH is the appropriate model for the conduction

  16. Optical, magnetic, and dielectric properties of opal matrices with intersphere nanocavities filled with crystalline multiferroic, piezoelectric, and segnetoelectric materials

    Czech Academy of Sciences Publication Activity Database

    Samoilovich, M.I.; Rinkevich, A.B.; Bovtun, Viktor; Belyanin, A.F.; Kempa, Martin; Nuzhnyy, Dmitry; Tsvetkov, M.Yu.; Klescheva, S.M.

    2013-01-01

    Roč. 83, č. 11 (2013), s. 2132-2147 ISSN 1070-3632 R&D Projects: GA ČR GAP204/12/0232 Institutional support: RVO:68378271 Keywords : composites * opal matrices * optical, magnetic, and dielectric properties Subject RIV: JI - Composite Materials Impact factor: 0.418, year: 2013

  17. Electrical, dielectric, and optical properties of Sb2O3–Li2O–MoO3 glasses

    Czech Academy of Sciences Publication Activity Database

    Kubliha, M.; Soltani, M.T.; Trnovcová, V.; Legouera, M.; Labaš, V.; Kostka, Petr; Le Coq, D.; Hamzaoui, M.

    2015-01-01

    Roč. 428, NOV 15 (2015), s. 42-48 ISSN 0022-3093 R&D Projects: GA ČR GAP106/12/2384 Institutional support: RVO:67985891 Keywords : lithium molybdenum–antimonite glasses * electrical conductivity * electrical relaxation * dielectric response * optical properties Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.825, year: 2015

  18. Growth, optical, thermal and dielectric studies of an amino acid organic nonlinear optical material: L-Alanine

    International Nuclear Information System (INIS)

    Caroline, M. Lydia; Sankar, R.; Indirani, R.M.; Vasudevan, S.

    2009-01-01

    Good transparent bulk single crystals of L-alanine (nonlinear optical material) have been grown successfully by slow cooling technique from aqueous solution at pH value of 2.0. Optically transparent crystals with dimensions 2.4 cm x 1.2 cm x 1.6 cm, were grown by optimizing the growth parameters within a growth period of 2 weeks. The crystallinity of L-alanine crystal was confirmed by the powder X-ray diffraction study and diffraction peaks are indexed. The vibrational structure of the molecule is elucidated from FTIR spectra. The thermal behaviour of the grown crystal was investigated by thermogravimetric (TG) and differential thermal analyses (DTA) techniques in a nitrogen atmosphere. The result showed that the material starts decomposing at 297 deg. C. Its optical behaviour has been examined by UV-vis spectral analysis, which shows the absence of absorbance between the wavelengths ranging from 200 to 1200 nm. The NLO property was confirmed by the powder technique of Kurtz and Perry. The dielectric behaviour of the sample was also studied for the first time

  19. Thermal, optical, and dielectric properties of fluoride Rb2TaF7

    Science.gov (United States)

    Pogorel'tsev, E. I.; Mel'nikova, S. V.; Kartashev, A. V.; Gorev, M. V.; Flerov, I. N.; Laptash, N. M.

    2017-05-01

    The thermal, optical, and dielectric properties of fluoride Rb2TaF7 were investigated. It was observed that the variation in chemical pressure in fluorides A 2 +TaF7 caused by the cation substitution of rubidium for ammonium does not affect the ferroelastic nature of structural distortions, but leads to stabilization of the high- and low-temperature phases and enhancement of birefringence. The entropy of the phase transition P4/nmm ↔ Cmma is typical of the shift transformations, which is consistent with a model of the initial and distorted phase structures. The anisotropy of chemical pressure causes the change of signs of the anomalous strain and baric coefficient dT/ dp of Rb2TaF7 as compared with the values for its ammonium analog.

  20. Thermal, mechanical, optical and dielectric properties of piperazinium hydrogen phosphite monohydrate NLO single crystal

    Science.gov (United States)

    Rajkumar, R.; Praveen Kumar, P.

    2018-05-01

    Optical transparent crystal of piperazinium hydrogen phosphite monohydrate (PHPM) was grown by slow evaporation method. The grown crystal was characterized by single crystal X-ray diffraction analysis and the crystal belongs to monoclinic system. The functional groups present in PHPM crystal were confirmed by FTIR analysis. UV-Visible spectrum shows that the PHPM crystal is transparent in the visible region. The mechanical behavior of PHPM crystal was characterized by Vickers hardness test. Thermal stability of PHPM crystal was analyzed by thermogravimetric analysis. Dielectric studies were also carried out for the grown crystal. The third-order nonlinear parameters such as nonlinear refractive index and nonlinear absorption coefficient have been calculated using Z scan technique.

  1. Probing the dielectric response of the interfacial buffer layer in epitaxial graphene via optical spectroscopy

    Science.gov (United States)

    Hill, Heather M.; Rigosi, Albert F.; Chowdhury, Sugata; Yang, Yanfei; Nguyen, Nhan V.; Tavazza, Francesca; Elmquist, Randolph E.; Newell, David B.; Hight Walker, Angela R.

    2017-11-01

    Monolayer epitaxial graphene (EG) is a suitable candidate for a variety of electronic applications. One advantage of EG growth on the Si face of SiC is that it develops as a single crystal, as does the layer below, referred to as the interfacial buffer layer (IBL), whose properties include an electronic band gap. Although much research has been conducted to learn about the electrical properties of the IBL, not nearly as much work has been reported on the optical properties of the IBL. In this work, we combine measurements from Mueller matrix ellipsometry, differential reflectance contrast, atomic force microscopy, and Raman spectroscopy, as well as calculations from Kramers-Kronig analyses and density-functional theory, to determine the dielectric function of the IBL within the energy range of 1 eV to 8.5 eV.

  2. Crystal structures, Hirshfeld surface analysis, thermal behavior and dielectric properties of a new organic-inorganic hybrid [C6H10(NH3)2]Cu2Cl8

    Science.gov (United States)

    Salah, Najet; Hamdi, Besma; Bouzidia, Nabaa; Salah, Abdelhamid Ben

    2017-12-01

    A novel organic-inorganic hybrid sample [C6H10(NH3)2]Cu2Cl8 has been prepared under mild hydrothermal conditions and characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, FT-IR,NMR and UV-Vis spectroscopies, differential scanning calorimetric and dielectric measurement. It is crystallized in the monoclinic system with P21/c space group. The cohesion and stabilization of the structure are provided by the hydrogen bond interactions, (Nsbnd H⋯Cl and Csbnd H⋯Cl), between [C6H10(NH3)2]2+ cation and [Cu2Cl8]2- anion. The Hirschfeld surface analysis has been performed to explore the behavior of these weak interactions. The presence of different functional groups and the nature of their vibrations were identified by FT-IR and Solid state NMR. The thermal study revealed that this compound undergoes two structural phase transitions around 353 and 376 K. Electrical measurements of our compounds have been investigated using complex impedance spectroscopy (CIS) in the frequency and temperature range 331-399 K and 200 Hz-5 MHz, respectively. The AC conductivity is explained using the correlated barrier hopping model (CBH) conduction mechanism. The nature of DC conductivity variation suggests Arrhenius type of electrical conductivity. A relationship between crystal structure and ionic conductivity was established and discussed. Finally, the real and imaginary parts of the permittivity constant are analyzed with the Cole-Cole formalism and the optical spectra indicate that the compound has a direct band gap (3.14 eV) due to direct transition. The wide band gap is due to low defect concentration in the grown crystal, which is more useful for the laser/optical applications.

  3. Optical spectroscopy, optical conductivity, dielectric properties and new methods for determining the gap states of CuSe thin films

    International Nuclear Information System (INIS)

    Sakr, G.B.; Yahia, I.S.; Fadel, M.; Fouad, S.S.; Romcevic, N.

    2010-01-01

    Research highlights: → The structural, optical dispersion parameters and the Raman spectroscopy have been studied for CuSe thin films. → X-ray diffraction results indicate the amorphous nature of the thermally evaporated CuSe thin films. → The refractive index shows an anomalous dispersion at the lower wavelength (absorption region) and a normal dispersion at the higher wavelengths (transparent region). → The refractive index dispersion obeys the single oscillator model proposed by Wemple and DiDomenico WDD model and the single oscillator parameters were determined. → The band gap of CuSe thin films was determined by three novel methods i.e. (relaxation time, real and imaginary dielectric constant and real and imaginary optical conductivity) which in a good agreement with the Tauc band gap value. - Abstract: The paper describes the structural and optical properties of CuSe thin films. X-ray diffraction pattern indicates that CuSe thin film has an amorphous structure. Transmittance T(λ) and reflectance R(λ) measurements in the wavelength range (300-1700 nm) were used to calculate the refractive index n(λ), the absorption index and the optical dispersion parameters according to Wemple and Didomenico WDD model. The dispersion curve of the refractive index shows an anomalous dispersion in the absorption region and a normal dispersion in the transparent region. The optical bandgap has been estimated and confirmed by four different methods. The value for the direct bandgap for the as-deposited CuSe thin film approximately equals 2.7 eV. The Raman spectroscopy was used to identify and quantify the individual phases presented in the CuSe films.

  4. Dielectric, optical and mechanical studies of phenolic polyene OH1 organic electrooptic crystal

    Science.gov (United States)

    Bharath, D.; Kalainathan, S.

    2014-11-01

    2-{3-[2-(4-Hydroxyphenyl) vinyl]-5, 5-dimethylcyclo-hex-2-en-1-ylidene}malononitrile (OH1) phenolic locked polyene organic material has been synthesized by the Knoevenagel condensation method. OH1 single crystals were grown in methanol by a slow evaporation method. In order to avoid the multinucleation and reduce the metastable zone width, phosphoric acid is added in different concentrations. The linear optical property of OH1 crystal has been studied using UV-vis-NIR spectroscopy in the wavelength range 190-1100 nm and optical constants are calculated theoretically. The magnitude of nonlinear refractive index (10-12 m2/W), nonlinear absorption (10-6 m/W) and third order nonlinear susceptibility (10-6 esu) has been studied using a Z-scan technique. Dielectric property of OH1 crystal has been studied in frequency range 50 Hz-5 MHz. Photoluminescence spectrum was recorded using a xenon lamp in the range of 450-700 nm. Laser optical damage threshold of OH1 crystal was obtained (0.62 GW/cm2) using a pulsed Nd-YAG laser (1064 nm) of repetition rate 10 ns.

  5. Pressure-Induced Structural and Optical Properties of Inorganic Halide Perovskite CsPbBr3.

    Science.gov (United States)

    Zhang, Long; Zeng, Qingxin; Wang, Kai

    2017-08-17

    Perovskite photovoltaic materials are gaining sustained attention because of their excellent photovoltaic properties and extensive practical applicability. In this Letter, we discuss the changes in the structure and optical properties of CsPbBr 3 under high pressure. As the pressure increased, the band gap initially began to red shift before 1.0 GPa followed by a continuous blue shift until the crystal was completely amorphized. An isostructural phase transition at 1.2 GPa was determined by high-pressure synchrotron X-ray and Raman spectroscopy. The result could be attributed to bond length shrinkage and PbBr 6 octahedral distortion under high pressure. The amorphization of the crystal was due to the severe distortion and tilt of the PbBr 6 octahedron, leading to broken long-range order. Changes in optical properties are closely related to the evolution of the crystal structure. Our discussion shows that high-pressure study can be used as an effective means to tune the structure and properties of all-inorganic halide perovskites.

  6. EFFECTS OF NEODYMIUM DOPING ON DIELECTRIC AND OPTICAL PROPERTIES OF Ba(1-xNdxTi1.005O3 CERAMICS

    Directory of Open Access Journals (Sweden)

    Zhang W.

    2013-06-01

    Full Text Available This paper investigated the optical properties and dielectric properties of neodymium doped BaTiO3 ceramics prepared by Ba(1-xNdxTi1.005O3 powders synthesized via a hydrothermal method. The effects of Nd3+ ions content on the structure, dielectric properties and optical properties of the ceramics were studied. The structural analysis performed on the X-ray diffractometer shows that the phase compositions of all ceramics are tetragonal phase structure. The red shift of the absorption edge indicates the presence of defect energy levels which was proved by the UV-Vis-NIR diffuse reflection spectra. Dielectric property measurements show that Nd-doped BaTiO3 ceramics possess improved dielectric properties at low Nd3+ contents (x = 0.001 and 0.002, as demonstrated by decreased dependence to frequency for both the dielectric constant and dielectric loss.

  7. Synthesis, Structural, Optical and Dielectric Properties of Nanostructured 0-3 PZT/PVDF Composite Films.

    Science.gov (United States)

    Revathi, S; Kennedy, L John; Basha, S K Khadheer; Padmanabhan, R

    2018-07-01

    Nanostructured PbZr0.52Ti0.48O3 (PZT) powder was synthesized at 500 °C-800 °C using sol-gel route. X-ray diffraction and Rietveld analysis confirmed the formation of perovskite structure. The sample heat treated at 800 °C alone showed the formation of morphotropic phase boundary with coexistence of tetragonal and rhombohedral phase. The PZT powder and PVDF were used in 0-3 connectivity to form the PZT/PVDF composite film using solvent casting method. The composite films containing 10%, 50%, 70% and 80% volume fraction of PZT in PVDF were fabricated. The XRD spectra validated that the PZT structure remains unaltered in the composites and was not affected by the presence of PVDF. The scanning electron microscopy images show good degree of dispersion of PZT in PVDF matrix and the formation of pores at higher PZT loading. The quantitative analysis of elements and their composition were confirmed from energy dispersive X-ray analysis. The optical band gap of the PVDF film is 3.3 eV and the band gap decreased with increase in volume fraction of PZT fillers. The FTIR spectra showed the bands corresponding to different phases of PVDF (α, β, γ) and perovskite phase of PZT. The thermogravimetric analysis showed that PZT/PVDF composite films showed better thermal stability than the pure PVDF film and hydrophobicity. The dielectric constant was measured at frequency ranging from 1 Hz to 6 MHz and for temperature ranging from room temperature to 150 °C. The composite with 50% PZT filler loading shows the maximum dielectric constant at the studied frequency and temperature range with flexibility.

  8. Investigation on nonlinear optical and dielectric properties of L-arginine doped ZTC crystal to explore photonic device applications

    Directory of Open Access Journals (Sweden)

    Anis Mohd

    2016-09-01

    Full Text Available The present study is focused to explore the photonic device applications of L-arginine doped ZTC (LA-ZTC crystals using nonlinear optical (NLO and dielectric studies. The LA-ZTC crystals have been grown by slow evaporation solution technique. The chemical composition and surface of LA-ZTC crystal have been analyzed by means of energy dispersive spectroscopy (EDS and surface scanning electron microscopy (SEM techniques. The Vicker’s microhardness study has been carried out to determine the hardness, work hardening index, yield strength and elastic stiffness of LA-ZTC crystal. The enhanced SHG efficiency of LA-ZTC crystal has been ascertained using the Kurtz-Perry powder SHG test. The closed-and-open aperture Z-scan technique has been employed to confirm the third order nonlinear optical nature of LA-ZTC crystal. The Z-scan transmittance data has been utilized to calculate the superior cubic susceptibility, nonlinear refractive index, nonlinear absorption coefficient and figure of merit of LA-ZTC crystal. The behavior of dielectric constant and dielectric loss of LA-ZTC crystal at different temperatures has been investigated using the dielectric analysis.

  9. Estimating the Optical Properties of Inorganic Matter-Dominated Oligo-to-Mesotrophic Inland Waters

    Directory of Open Access Journals (Sweden)

    Thanan Rodrigues

    2018-04-01

    Full Text Available Many studies over the years have focused on bio-optical modeling of inland waters to monitor water quality. However, those studies have been conducted mainly in eutrophic and hyper-eutrophic environments dominated by phytoplankton. With the launch of the Ocean and Land Colour Instrument (OLCI/Sentinel-3A in 2016, a range of bands became available including the 709 nm band recommended for scaling up these bio-optical models for productive inland waters. It was found that one category of existing bio-optical models, the quasi-analytical algorithms (QAAs, when applied to colored dissolved organic matter (CDOM and detritus-dominated waters, produce large errors. Even after shifting the reference wavelength to 709 nm, the recently re-parameterized QAA versions could not accurately retrieve the inherent optical properties (IOPs in waterbodies dominated by inorganic matter. In this study, three existing versions of QAA were implemented and proved inefficient for the study site. Therefore, several changes were incorporated into the QAA, starting with the re-parameterization of the empirical steps related to the total absorption coefficient retrieval. The re-parameterized QAA, QAAOMW showed a significant improvement in the mean absolute percentage error (MAPE. MAPE decreased from 58.05% for existing open ocean QAA (QAALv5 to 16.35% for QAAOMW. Considerable improvement was also observed in the estimation of the absorption coefficient of CDOM and detritus from a MAPE of 91.05% for QAALv5 to 18.87% for QAAOMW. The retrieval of the absorption coefficient of phytoplankton ( a ϕ using the native form of QAA proved to be inaccurate for the oligo-to-mesotrophic waterbody due to the low a ϕ returning negative predictions. Therefore, a novel approach based on the normalized a ϕ was adopted to maintain the spectral shape and retrieve positive values, resulting in an improvement of 119% in QAAOMW. Further tuning and scale-up of QAAOMW to OLCI bands will aid in

  10. Optical studies of photoactive states in mixed organic-inorganic hybrid perovskites stabilized in polymers

    Science.gov (United States)

    Kardynal, Beata; Xi, Lifei; Salim, Teddy; Borghardt, Sven; Stoica, Toma; Lam, Yeng Ming

    2015-03-01

    Mixed organic-inorganic hybrid perovskites MAX-PbY2(X,Y =I, Br,Cl) have been demonstrated as very attractive materials for absorbers of solar cells and active layers of light emitting diodes and optically driven lasers. The bandgap of the perovskites can be tuned by mixing halogen atoms in different ratios. In this presentation we study mixed MAX-PbY2(X,Y =I, Br, Cl) particles synthesized directly in protective polymer matrices as light emitters. Both, time integrated and time resolved photoluminescence have been used to study the materials. So synthesized MAX-PbX2 are very stable when measured at room temperature and in air with radiative recombination of photogenerated carriers as the main decay path. In contrast, MAX-PbY2 with mixed halogen atoms display luminescence from sub-bandgap states which saturate at higher excitation levels. The density of these states depends on the used polymer matrix and increases upon illumination. We further compare the MAX-PbY2 synthesized in polymers and as films and show that these states are inherent to the material rather than its microstructure. This works has been supported by EU NWs4LIGHT grant.

  11. Changes of optical, dielectric, and structural properties of Si15Sb85 phase change memory thin films under different initializing laser power

    International Nuclear Information System (INIS)

    Huang Huan; Zhang Lei; Wang Yang; Han Xiaodong; Wu Yiqun; Zhang Ze; Gan Fuxi

    2011-01-01

    Research highlights: → We study the optical, dielectric, and structural characteristics of Si 15 Sb 85 phase change memory thin films under a moving continuous-wave laser initialization. → The optical and dielectric constants, absorption coefficient of Si 15 Sb 85 change regularly with the increasing laser power. → The optical band gaps of Si 15 Sb 85 irradiated upon different power lasers were calculated. → HRTEM images of the samples were observed and the changes of optical and dielectric constants are determined by crystalline structures changes of the films. - Abstract: The optical, dielectric, and structural characteristics of Si 15 Sb 85 phase change memory thin films under a moving continuous-wave laser initialization are studied by using spectroscopic ellipsometry and high-resolution transmission electron microscopy. The dependence of complex refractive index, dielectric functions, absorption coefficient, and optical band gap of the films on its crystallization extents formed by the different initialization laser power are analyzed in detail. The structural change from as-deposited amorphous phase to distorted rhombohedra-Sb-like crystalline structure with the increase of initialization laser power is clearly observed with sub-nanometer resolution. The optical and dielectric constants, the relationship between them, and the local atomic arrangements of this new phase change material can help explain the phase change mechanism and design the practical phase change memory devices.

  12. Transition from two-dimensional photonic crystals to dielectric metasurfaces in the optical diffraction with a fine structure

    Science.gov (United States)

    Rybin, Mikhail V.; Samusev, Kirill B.; Lukashenko, Stanislav Yu.; Kivshar, Yuri S.; Limonov, Mikhail F.

    2016-01-01

    We study experimentally a fine structure of the optical Laue diffraction from two-dimensional periodic photonic lattices. The periodic photonic lattices with the C4v square symmetry, orthogonal C2v symmetry, and hexagonal C6v symmetry are composed of submicron dielectric elements fabricated by the direct laser writing technique. We observe surprisingly strong optical diffraction from a finite number of elements that provides an excellent tool to determine not only the symmetry but also exact number of particles in the finite-length structure and the sample shape. Using different samples with orthogonal C2v symmetry and varying the lattice spacing, we observe experimentally a transition between the regime of multi-order diffraction, being typical for photonic crystals to the regime where only the zero-order diffraction can be observed, being is a clear fingerprint of dielectric metasurfaces characterized by effective parameters. PMID:27491952

  13. Electrical and optical characteristics of the radio frequency surface dielectric barrier discharge plasma actuation

    International Nuclear Information System (INIS)

    Wang Wei-Long; Song Hui-Min; Li Jun; Jia Min; Wu Yun; Jin Di

    2016-01-01

    Electrical characteristics and optical emission spectrum of the radio frequency (RF) surface dielectric barrier discharge (SDBD) plasma actuation are investigated experimentally in this paper. Influences of operating pressure, duty cycle and load power on the discharge are analyzed. When the operating pressure reaches 30 kPa, the discharge energy calculated from the Charge–Voltage (Q–V) Lissajous figure increases significantly, while the effective capacitance decreases remarkably. As the duty cycle of the applied voltage increases, the voltage–current waveforms, the area of Q–V loop and the capacity show no distinct changes. Below 40 W, effective capacitance increases with the increase of load power, but it almost remains unchanged when load power is between 40 W and 95 W. The relative intensity changes little as the operating pressure varies from 4 kPa to 100 kPa, while it rises evidently with the pressure below 4 kPa, which indicates that the RF discharge mode shifts from filamentary discharge to glow discharge at around 4 kPa. With the increase of load power, the relative intensity rises evidently. Additionally, the relative intensity is insensitive to the pressure, the duty cycle, and the load power. (paper)

  14. Distributed grating-assisted coupler for optical all-dielectric electron accelerator

    Directory of Open Access Journals (Sweden)

    Zhiyu Zhang

    2005-07-01

    Full Text Available A Bragg waveguide consisting of multiple dielectric layers with alternating index of refraction becomes an excellent option to form electron accelerating structure powered by high power laser sources. It provides confinement of a synchronous speed-of-light mode with extremely low loss. However, laser field cannot be coupled into the structure collinearly with the electron beam. There are three requirements in designing input coupler for a Bragg electron accelerator: side coupling, selective mode excitation, and high coupling efficiency. We present a side-coupling scheme using a distributed grating-assisted coupler to inject the laser power into the waveguide. Side coupling is achieved by a grating with a period on the order of an optical wavelength. The phase matching condition results in resonance coupling thus providing selective mode excitation capability. The coupling efficiency is limited by profile matching between the outgoing beam and the incoming beam, which has normally a Gaussian profile. We demonstrate a nonuniform distributed grating structure generating an outgoing beam with a Gaussian profile, therefore, increasing the coupling efficiency.

  15. Structural and optical studies of local disorder sensitivity in natural organic-inorganic self-assembled semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Vijaya Prakash, G; Pradeesh, K [Nanophotonics Lab, Department of Physics, Indian Institute of Technology Delhi, New Delhi (India); Ratnani, R; Saraswat, K [Department of Pure and Applied Chemistry, MDS University, Ajmer (India); Light, M E [School of Chemistry, University of Southampton, Southampton (United Kingdom); Baumberg, J J, E-mail: prakash@physics.iitd.ac.i [Nanophotonic Centre, Cavendish Laboratory, University Cambridge, Cambridge CB3 OHE (United Kingdom)

    2009-09-21

    The structural and optical spectra of two related lead iodide (PbI) based self-assembled hybrid organic-inorganic semiconductors are compared. During the synthesis, depending on the bridging of organic moiety intercalated between the PbI two-dimensional planes, different crystal structures are produced. These entirely different networks show different structural and optical features, including excitonic bandgaps. In particular, the modified organic environment of the excitons is sensitive to the local disorder both in single crystal and thin film forms. Such information is vital for incorporating these semiconductors into photonic device architectures.

  16. Electro-optical and dielectric properties of CdSe quantum dots and 6CHBT liquid crystals composites

    Energy Technology Data Exchange (ETDEWEB)

    Singh, U. B.; Pandey, M. B., E-mail: mbpandey@gmail.com [Department of Physics, Vikramajit Singh Sanatan Dharama College, Kanpur-208002 (India); Dhar, R; Pandey, A. S. [Centre of Material Sciences, Institute of Interdisciplinary Studies, University of Allahabad, Allahabad-211002 (India); Kumar, S. [Raman Research Institute, C. V. Raman Avenue, Bangalore-560080 (India); Dabrowski, R. [Institute of Applied Sciences and Chemistry, Military University of Technology, 00-908-Warswa (Poland)

    2014-11-15

    We have prepared the composites of a room temperature nematic liquid crystal namely 4-(trans-4-n-hexylcyclohexyl) isothiocyanatobenzoate (6CHBT) and Cadmium Selenide Quantum Dots (CdSe-QDs) and investigated their electro-optical and dielectric properties. Effect of dispersion of CdSe-QDs on various electro-optical and display parameters of host liquid crystalline material have been studied. Physical parameters, such as switching threshold voltage and splay elastic constant have been altered drastically for composites. Dispersion of QDs in a liquid crystals medium destabilizes nematic ordering of the host and decreases the nematic-to-isotropic transition temperature.

  17. Determination of basic state parameters and characterization of optical, dielectric and fluorescence properties of calcium boro lactate (CaBL)

    International Nuclear Information System (INIS)

    Vijayalakshmi, A.; Balraj, V.

    2016-01-01

    This paper describes the calculation of basic solid state parameters like penn gap, plasma energy, polarizability and fermi energy for calcium boro lactate single crystal. calcium boro lactate crystals were developed by solution growth method. Single crystal diffraction studies carried out and calculated basic solid state criterion for the CaBL compound. optical nature of these compound explained by using UV-Visible spectrum. Electro-optic behaviour of the crystal explained by dielectric studies. Light emitting properties explained by fluorescence studies. (author)

  18. Electro-optical and dielectric properties of CdSe quantum dots and 6CHBT liquid crystals composites

    International Nuclear Information System (INIS)

    Singh, U. B.; Pandey, M. B.; Dhar, R; Pandey, A. S.; Kumar, S.; Dabrowski, R.

    2014-01-01

    We have prepared the composites of a room temperature nematic liquid crystal namely 4-(trans-4-n-hexylcyclohexyl) isothiocyanatobenzoate (6CHBT) and Cadmium Selenide Quantum Dots (CdSe-QDs) and investigated their electro-optical and dielectric properties. Effect of dispersion of CdSe-QDs on various electro-optical and display parameters of host liquid crystalline material have been studied. Physical parameters, such as switching threshold voltage and splay elastic constant have been altered drastically for composites. Dispersion of QDs in a liquid crystals medium destabilizes nematic ordering of the host and decreases the nematic-to-isotropic transition temperature

  19. [Study on A White-Eye Pattern in Dielectric Barrier Discharge by Optical Emission Spectrum].

    Science.gov (United States)

    Zhu, Ping; Dong, Li-fang; Yang, Jing; Zhang, Yu; Zhang, Chao

    2015-06-01

    The white-eye pattern was firstly observed and investigated in a dielectric barrier discharge system in the mixture of argon and air whose content can be varied whenever necessary, and the study shows that the white-eye cell is an interleaving of three different hexagonal sub-structures: the center spot, the halo, and the ambient spots. The white-eye pattern is observed at a lower applied voltage. In this experiment, the heat capacity of water is high so that the water in water electrode is good at absorbing heat. In the process of pattern discharging the gas gap didn't increase its temperature, and the discharging phenomenon of this pattern has not changed. The temperature of the water electrodes almost keeps unchanged during the whole experiment, which is advantageous for the long-term stable measurement. Pictures recorded by ordinary camera with long exposure time in the same argon content condition show that the center spot, the halo, and the ambient spots og the white-eye pattern have different brightness, which may prove that their plasma states are different. And, it is worth noting that there are obvious differences of brightness not only on the center spot, the halo, and the ambient spots at the same pressure but also at the different pressure, which shows that its plasma state also changed with the variation of the pressure. Given this, in this experiment plasma temperatures of the central spot, halo, and ambient spots in a white-eye pattern at different gas pressure were studied by using optical emission spectra. The molecular vibration temperature is investigated by the emission spectra of nitrogen band of second positive system ( C3Πu --> B3Πg ). The electron excitation temperature is researched by the relative intensity ratio method of spectral lines of Ar I 763. 51 nm (2P6 --> 1S5) and Ar I 772. 42 nm (2P2 --> 1S3). The electronic density is investigated by the broadening of spectral line 696.5 nm. Through the analysis of experimental results, it

  20. Study of the physical mechanisms involved in the femtosecond laser optical breakdown of dielectric materials

    International Nuclear Information System (INIS)

    Mouskeftaras, Alexandros

    2013-01-01

    We have carried out detailed time resolved experimental studies of the mechanism of electron excitation-relaxation, when an ultrashort (60 fs -1 ps) laser (UV and IR) pulse interacts with a wide band gap dielectric material. The studies cover a range of different dielectric materials and the investigated regimes span from nondestructive ionization of the material at the low power end (∼TW/cm 2 ) to ablative domain at a higher laser power (∼10 TW/cm 2 ). This gives fundamental insight into the understanding of the laser damaging process taking place under our irradiation conditions. The usage of time-resolved spectral interferometry technique allows to directly measure the electron density of the irradiated material under different excitation conditions and hence leads to quantification of the process. The measurements, carried out at the optical breakdown threshold utilizing different pulse durations, raise questions regarding the usage of critical excitation density as a universal ablation criterion. A new criterion related to the exchanged energy is proposed. Additionally, the use of an experimental setup implementing a double pump pulse allows the identification of different excitation mechanisms taking place at time scales of the order of the pulse duration used. Electronic avalanche is observed in some materials (SiO 2 , NaCl) while this is not the case for others (Al 2 O 3 , MgO). These differences are discussed in detail. Next, we measure the energy spectrum of excited electrons with a complementary technique: the photoemission spectroscopy. These results allow us on one hand to show a crossed effect between the two 'pump' pulses and on the other hand to measure electron relaxation characteristic times, as a function of their kinetic energy. Finally, a morphological study of craters resulting from ablation in the case of a single pulse has been carried out for different irradiation parameters: number of shots, energy and pulse duration. This work has

  1. Studies on the structural, optical and dielectric properties of samarium coordinated with salicylic acid single crystal

    Science.gov (United States)

    Singh, Harjinder; Slathia, Goldy; Gupta, Rashmi; Bamzai, K. K.

    2018-04-01

    Samarium coordinated with salicylic acid was successfully grown as a single crystal by low temperature solution technique using mixed solvent of methanol and water in equal ratio. Structural characterization was carried out by single crystal X-ray diffraction analysis and it crystallizes in centrosymmetric space group P121/c1. FTIR and UV-Vis-NIR spectroscopy confirmed the compound formation and help to determine the mode of binding of the ligand to the rare earth-metal ion. Dielectric constant and dielectric loss have been measured over the frequency range 100 Hz - 30MHz. The decrease in dielectric constant with increases in frequency is due to the transition from interfacial polarization to dipolar polarization. The small value of dielectric constant at higher frequency ensures that the crystal is good candidate for NLO devices. Dielectric loss represents the resistive nature of the material.

  2. Excitation of photonic atoms (dielectric microspheres) on optical fibers: application to room-temperature persistent spectral hole burning

    Science.gov (United States)

    Serpenguzel, Ali; Arnold, Stephen; Griffel, Giora

    1995-05-01

    Recently, photonic atoms (dielectric microspheres) have enjoyed the attention of the optical spectroscopy community. A variety of linear and nonlinear optical processes have been observed in liquid microdroplets. But solid state photonic devices using these properties are scarce. A first of these applications is the room temperature microparticle hole-burning memory. New applications can be envisioned if microparticle resonances can be coupled to traveling waves in optical fibers. In this paper we demonstrate the excitation of narrow morphology dependent resonances of microparticles placed on an optical fiber. Furthermore we reveal a model for this process which describes the coupling efficiency in terms of the geometrical and material properties of the microparticle-fiber system.

  3. Theory of the optical and microwave properties of metal-dielectric films

    International Nuclear Information System (INIS)

    Sarychev, A.K.; Bergman, D.J.; Yagil, Y.

    1995-01-01

    We present a detailed theoretical study of the high frequency response of thin, metal-dielectric inhomogeneous films. Semicontinuous metal films are normally prepared by thermal evaporation or sputtering of the metal on an insulating substrate. The optical properties of such films show anomalous phenomena, which are absent in both the bulk metal and the bulk insulator. Our approach is based upon a direct solution of Maxwell's equations, without having to invoke the quasi-static approximation. Electric and magnetic fields outside the film are related to the currents inside the film. The electromagnetic properties of semicontinuous films are described by two Ohmic parameters, in contrast with the usual description by a single complex conductivity. Our theory reproduces most of the known experimental data. For example, we are able to explain a prominent absorption band near the percolation threshold, which was observed previously in such systems, as well as some other peculiar features of the reflectance and transmittance. We find that metal-dieletric films can exhibit very interesting properties when there is a strong skin effect in the metal grains. The surface conductivity has a universal value c/(2π) at the percolation threshold. We predict that under such conditions the absorptance A, as a funciton of the metal concentration, is dome shaped with sharp edges. It has a maximum at the percolation threshold and its value at this point is universal, namely A=0.5, while the reflectance R and transmittance T have the equal universal value R=T=0.25. This approach can be extended to semicontinuous superconducting films. Such films are also expected to have a well defined absorption band near the percolation threshold. We believe that such a threshold can be approached not only by decreasing the superconductor concentration but also by increasing the temperature towards and above the critical temperature

  4. Optical properties and thermal stability of LaYbO3 ternary oxide for high-k dielectric application

    Science.gov (United States)

    Su, Wei-tao; Yang, Li; Li, Bin

    2011-01-01

    A new ternary rare oxide dielectric LaYbO3 film had been prepared on silicon wafers and quartz substrates by reactive sputtering method using a La-Yb metal target. A range of analysis techniques was performed to determine the optical band gap, thermal stability, and electrical property of the deposited samples. It was found the band gap of LaYbO3 film was about 5.8 eV. And the crystallization temperature for rapid thermal annealing (20 s) was between 900 and 950 °C. X-ray photoelectron spectroscopy results indicate the formation of the SiO2 and silicate in the interface between silicon wafer and LaYbO3 film. The dielectric constant is about 23 from the calculation of capacitance-voltage curve, which is comparable higher than previously reported La2O3 or Yb2O3 film.

  5. Quenching Mo optical losses in CIGS solar cells by a point contacted dual-layer dielectric spacer: a 3-D optical study.

    Science.gov (United States)

    Rezaei, Nasim; Isabella, Olindo; Vroon, Zeger; Zeman, Miro

    2018-01-22

    A 3-D optical modelling was calibrated to calculate the light absorption and the total reflection of fabricated CIGS solar cells. Absorption losses at molybdenum (Mo) / CIGS interface were explained in terms of plasmonic waves. To quench these losses, we assumed the insertion of a lossless dielectric spacer between Mo and CIGS, whose optical properties were varied. We show that such a spacer with low refractive index and proper thickness can significantly reduce absorption in Mo in the long wavelength regime and improve the device's rear reflectance, thus leading to enhanced light absorption in the CIGS layer. Therefore, we optimized a realistic two-layer MgF 2 / Al 2 O 3 dielectric spacer to exploit (i) the passivation properties of ultra-thin Al 2 O 3 on the CIGS side for potential high open-circuit voltage and (ii) the low refractive index of MgF 2 on the Mo side to reduce its optical losses. Combining our realistic spacer with optically-optimized point contacts increases the implied photocurrent density of a 750 nm-thick CIGS layer by 10% for the wavelengths between 700 and 1150 nm with respect to the reference cell. The elimination of plasmonic resonances in the new structure leads to a higher electric field magnitude at the bottom of CIGS layer and justifies the improved optical performance.

  6. Real-time optical modelling and investigation of inorganic nano-layer growth onto flexible polymeric substrates

    International Nuclear Information System (INIS)

    Laskarakis, A.; Georgiou, D.; Logothetidis, S.

    2010-01-01

    A major factor for the achievement of the desirable performance, efficiency and lifetime of flexible organic electronic devices is the optimization of the encapsulation layers that protect the device active layers by atmospheric gas molecule permeation. The active layers consisted of small molecule and/or polymer organic semiconductors as well as the organic conductors need to be encapsulated into a transparent medium that will provide the necessary protection and maintain their charge generation and transport characteristics. The encapsulation layers are generally consisted of inorganic thin films (silicon oxide-SiO x and aluminium oxide-AlO x ) deposited onto the polymeric substrates, such as PolyEthylene Terephthalate (PET). In this work, in situ and real-time Spectroscopic Ellipsometry in the ultraviolet spectral region has been implemented in order to investigate the growth of inorganic SiO x and AlO x nano-layers onto PET flexible polymeric substrates as well as the PET/inorganic interface effects during the early stages of growth. The analysis of the pseudodielectric function that was measured in real-time in very short time scales (in the order of hundreds of ms) has provided detailed information on the time evolution of the thickness and deposition rate of the inorganic nano-layers during their growth process as well as on their optical and electronic properties. This work proposes a methodology for using real-time optical monitoring technique with the aim to tailor and control the functionality of these materials for application in flexible electronic devices.

  7. Tuning the dielectric properties of thiourea analog crystals for efficient nonlinear optical applications

    International Nuclear Information System (INIS)

    Sabari Girisun, T.C.; Dhanuskodi, S.

    2010-01-01

    Materials with low dielectric constant have attracted a great deal of interest in the field of nonlinear applications and microelectronic industry. Metal complexes of thiourea with group II transition metals (Zn, Cd) as central atom and period III elements (S, Cl) were synthesized by chemical reaction method and single crystals were grown from aqueous solution by slow evaporation method. By parallel plate capacitor technique, the dielectric response, dissipation factor, ac conductivity and impedance of virgin and metal complexes have been studied in the frequency (100 Hz to 5 MHz) and temperature (303-423 K) ranges. Metal complexes of thiourea with cadmium substitute have a low dielectric constant less than 10. Also the presence of chlorine in the metal complex induces noncentro symmetric structure. Hence the role of group II transition metals and period III elements in tuning the dielectric properties for efficient nonlinear applications has been studied.

  8. Dielectric relaxation and optical properties of 4-amino-3-mercapto-6 ...

    Indian Academy of Sciences (India)

    2016-12-03

    Dec 3, 2016 ... by means of molecular engineering [1,2]. Organic electronics is accepted as a future technology for the ... The experimental approaches based on dielectrics .... applied on the synthesis of organic compounds [21,22]. Figure 4 ...

  9. Influence of size-corrected bound-electron contribution on nanometric silver dielectric function. Sizing through optical extinction spectroscopy

    International Nuclear Information System (INIS)

    Santillán, J M J; Videla, F A; Scaffardi, L B; Schinca, D C; Fernández van Raap, M B; Muraca, D

    2013-01-01

    The study of metal nanoparticles (NPs) is of great interest due to their ability to enhance optical fields on the nanometric scale, which makes them interesting for various applications in several fields of science and technology. In particular, their optical properties depend on the dielectric function of the metal, its size, shape and surrounding environment. This work analyses the contributions of free and bound electrons to the complex dielectric function of spherical silver NPs and their influence on the optical extinction spectra. The contribution of free electrons is usually corrected for particle size under 10 nm, introducing a modification of the damping constant to account for the extra collisions with the particle's boundary. For the contribution of bound electrons, we considered the interband transitions from the d-band to the conduction band including the size dependence of the electronic density states for radii below 2 nm. Bearing in mind these specific modifications, it was possible to determine optical and band energy parameters by fitting the bulk complex dielectric function. The results obtained from the optimum fit are: K bulk = 2 × 10 24 (coefficient for bound-electron contribution), E g = 1.91 eV (gap energy), E F = 4.12 eV (Fermi energy), and γ b = 1.5 × 10 14 Hz (damping constant for bound electrons). Based on this size-dependent dielectric function, extinction spectra of silver particles in the nanometric–subnanometric radius range can be calculated using Mie's theory, and its size behaviour analysed. These studies are applied to fit experimental extinction spectrum of very small spherical particles fabricated by fs laser ablation of a solid target in water. From the fitting, the structure and size distribution of core radius and shell thickness of the colloidal suspension could be determined. The spectroscopic results suggest that the colloidal suspension is composed by two types of structures: bare core and core–shell. The former

  10. Growth and dielectric, mechanical, thermal and etching studies of an organic nonlinear optical L-arginine trifluoroacetate (LATF) single crystal

    International Nuclear Information System (INIS)

    Arjunan, S.; Mohan Kumar, R.; Mohan, R.; Jayavel, R.

    2008-01-01

    L-arginine trifluoroacetate, an organic nonlinear optical material, has been synthesized from aqueous solution. Bulk single crystal of dimension 57 mm x 5 mm x 3 mm has been grown by temperature lowering technique. Powder X-ray diffraction studies confirmed the monoclinic structure of the grown L-arginine trifluoroacetate crystal. Linear optical property of the grown crystal has been studied by UV-vis spectrum. Dielectric response of the L-arginine trifluoroacetate crystal was analysed for different frequencies and temperatures in detail. Microhardness study on the sample reveals that the crystal possesses relatively higher hardness compared to many organic crystals. Thermal analyses confirmed that the L-arginine trifluoroacetate material is thermally stable upto 212 deg. C. The etching studies have been performed to assess the perfection of the L-arginine trifluoroacetate crystal. Kurtz powder second harmonic generation test confirms the nonlinear optical properties of the as-grown L-arginine trifluoroacetate crystal

  11. Data Transmission and Thermo-Optic Tuning Performance of Dielectric-Loaded Plasmonic Structures Hetero-Integrated on a Silicon Chip

    DEFF Research Database (Denmark)

    Giannoulis, G.; Kalavrouziotis, D.; Apostolopoulos, D.

    2012-01-01

    We demonstrate experimental evidence of the data capture and the low-energy thermo-optic tuning credentials of dielectric-loaded plasmonic structures integrated on a silicon chip. We show 7-nm thermo-optical tuning of a plasmonic racetrack-resonator with less than 3.3 mW required electrical power...

  12. Synthesis, structural, thermal and optical studies of inorganic-organic hybrid semiconductors, R-PbI4

    Science.gov (United States)

    Pradeesh, K.; Nageswara Rao, K.; Vijaya Prakash, G.

    2013-02-01

    Wide varieties of naturally self-assembled two-dimensional inorganic-organic (IO) hybrid semiconductors, (4-ClC6H4NH3)2PbI4, (C6H9C2H4NH3)2PbI4, (CnH2n+1NH3)2PbI4 (where n = 12, 16, 18), (CnH2n-1NH3)2PbI4 (where n = 3, 4, 5), (C6H5C2H4NH3)2PbI4, NH3(CH2)12NH3PbI4, and (C4H3SC2H4NH3)2PbI4, were fabricated by intercalating structurally diverse organic guest moieties into lead iodide perovskite structure. The crystal packing of all these fabricated IO-hybrids comprises of well-ordered organic and inorganic layers, stacked-up alternately along c-axis. Almost all these hybrids are thermally stable upto 200 °C and show strong room-temperature exciton absorption and photoluminescence features. These strongly confined optical excitons are highly influenced by structural deformation of PbI matrix due to the conformation of organic moiety. A systematic correlation of optical exciton behavior of IO-hybrids with the organic/inorganic layer thicknesses, intercalating organic moieties, and various structural disorders were discussed. This systematic study clearly suggests that the PbI layer crumpling is directly responsible for the tunability of optical exciton energy.

  13. Electro-optic and magneto-dielectric properties of multifunctional nitride and oxide materials

    Science.gov (United States)

    Dixit, Ambesh

    with a spin polarization of ˜40% +/- 5% , suggesting strong correlation between electron carriers and observed ferromagnetism. Another In-based multifunctional material that has been explored is defect-rich In2O3. This system exhibits numerous interesting properties such as being simultaneously transparent and electrically conducting and above room temperature ferromagnetism together with semiconducting properties. The oxygen stoichiometry in In2O3 plays a crucial role in determining its optical, electronic, and magnetic properties. The effect of oxygen vacancies on different physical properties has been investigated. Our results suggest that as grown, nearly stoichiometric In2O 3 thin films exhibit strong photopersistent current with very long carrier lifetime. Heat treatment under reduced oxygen environment creates oxygen vacancies in these films, producing electron donors. Thus vacuum annealed In2O 3 becomes a highly degenerate n-type conductor. Oxygen deficient In 2O3 can be used as transparent conducting oxide without any further doping, which allows the conductivity to be switched reversibly by thermal annealing in air or vacuum. In addition highly oxygen deficient In 2O3 films exhibit ferromagnetism above room temperature. We have also investigated oxide based magnetoelectric multiferroics which show simultaneous magnetic and ferroelectric properties. This study included detailed investigations of YMnO3, Ni3V2O 8 and FeVO4, where we have investigated FeVO4 a new multiferroic system in the vanadate family. The main focus of this project was to understand the microscopic origin of the magnetoelectric coupling and cross-control of different ferroic order parameters in these system. We have synthesized bulk Ni3V2O8 and FeVO4 ceramics and characterized the thermal, magnetic, dielectric and magnetodielectric response of these samples in bulk form. To understand the cross-control of magnetic and ferroelectric order parameter we deposited thin films of Ni 3V2O8 and Fe

  14. Data base of radiation-resistant dielectric and insulating materials

    International Nuclear Information System (INIS)

    Hama, Yoshimasa; Sunazuka, Hideo; Nashiyama, Isamu; Kakuta, Tsunemi.

    1987-01-01

    In the data base of radiation-resistant dielectric and insulating materials, the data format contains such items as to give the summary; the data sheet contains the data in concrete form of respective properties from the references; the sheet of references contains the references in the former two. In the above three, there are attached code No., data sheet No., reference No. and key words. In the three areas as radiation-resistant dielectric and insulating materials, i.e., organic materials, inorganic materials and optical fibers, the following are explained: data format, data sheet and objectives. (Mori, K.)

  15. Synthesis and controlling the optical and dielectric properties of CMC/PVA blend via γ-rays irradiation

    Energy Technology Data Exchange (ETDEWEB)

    El Sayed, A.M., E-mail: ams06@fayoum.edu.eg

    2014-02-15

    Highlights: • PVA/CMC blend films were prepared by solution casting method. • The films were irradiated with γ-rays at the dose range of 0–70 kGy. • UV-vis spectroscopy was performed to study the changes in the optical properties. • The influence of γ-rays irradiation on the dielectric relaxation was studied. -- Abstract: Carboxymethyl cellulose (CMC)/Polyvinyl alcohol (PVA) blend films were prepared by solution casting method. Then, these films were irradiated with γ-rays from a Co-60 source at doses over the range 0–70 kGy to investigate the modifications induced in the optical and dielectric properties. The dielectric constant (ε′) was measured in the temperature range 303–408 K and in the frequency range 10 kHz–1 MHz. The indirect optical band gap was found to increase within the dose range 0–10 kGy, and to decrease at the higher doses. The refractive index values, however, showed a reversed behavior. The highest transmittance percentage was obtained at 10 kGy dose. According to the frequency and temperature dependence of ε′, α- relaxation peaks were observed in all samples and assigned to the micro-Brownian motion of the blend chains. The values of ε′ showed a decrease in the dose range 0–10 kGy and an increase in the dose range 10–70 kGy. The ac conductivity σ{sub ac} (T) showed an Arrhenius type behavior separated into two distinct regions. The results of the present system are compared with those of similar materials.

  16. Synthesis and controlling the optical and dielectric properties of CMC/PVA blend via γ-rays irradiation

    International Nuclear Information System (INIS)

    El Sayed, A.M.

    2014-01-01

    Highlights: • PVA/CMC blend films were prepared by solution casting method. • The films were irradiated with γ-rays at the dose range of 0–70 kGy. • UV-vis spectroscopy was performed to study the changes in the optical properties. • The influence of γ-rays irradiation on the dielectric relaxation was studied. -- Abstract: Carboxymethyl cellulose (CMC)/Polyvinyl alcohol (PVA) blend films were prepared by solution casting method. Then, these films were irradiated with γ-rays from a Co-60 source at doses over the range 0–70 kGy to investigate the modifications induced in the optical and dielectric properties. The dielectric constant (ε′) was measured in the temperature range 303–408 K and in the frequency range 10 kHz–1 MHz. The indirect optical band gap was found to increase within the dose range 0–10 kGy, and to decrease at the higher doses. The refractive index values, however, showed a reversed behavior. The highest transmittance percentage was obtained at 10 kGy dose. According to the frequency and temperature dependence of ε′, α- relaxation peaks were observed in all samples and assigned to the micro-Brownian motion of the blend chains. The values of ε′ showed a decrease in the dose range 0–10 kGy and an increase in the dose range 10–70 kGy. The ac conductivity σ ac (T) showed an Arrhenius type behavior separated into two distinct regions. The results of the present system are compared with those of similar materials

  17. All-optical tuning of EIT-like dielectric metasurfaces by means of chalcogenide phase change materials.

    Science.gov (United States)

    Petronijevic, E; Sibilia, C

    2016-12-26

    Electromagnetically induced transparency (EIT) is a pump-induced narrowband transparency window within an absorption line of the probe beam spectrum in an atomic system. In this paper we propose a way to bring together the all-dielectric metamaterials to have EIT-like effects and to optically tune the response by hybridizing them with a layer of a phase change material. We propose a design of the metamaterial based on Si nanoresonators that can support an EIT-like resonant response. On the top of the resonators we consider a thin layer of a chalcogenide phase change material, which we will use to tune the optical response. Our choice is Ge2Sb2Te5 (GST), since it has two stable phases at room temperature, namely amorphous and crystalline, between which it can be switched quickly, nonvolatively and reversibly, sustaining a large number of switching cycles. They differ in optical properties, while still having moderately low losses in telecom range. Since such dielectric resonators do not have non-radiative losses of metals around 1550nm, they can lead to a high-Q factor of the EIT-like response in this range. Firstly, we optimize the starting structure so that it gives an EIT-like response at 1550 nm when the GST layer is in the amorphous state. Our starting design uses glass as a substrate, but we also consider implementation in SOI technology. If we then switch the thin layer of GST to its crystalline phase, which has higher losses, the EIT-like response is red shifted, providing around 10:1 contrast at 1550nm. This reversible tuning can be done with an ns visible pulsed laser. We discuss the results of the simulation of the dielectric metasurface for different configurations and the tuning possibility.

  18. A study on the optical, structural, electrical conductivity and dielectric properties of a lithium bismuth germanium tungsten glasses

    Energy Technology Data Exchange (ETDEWEB)

    Salem, Shaaban M., E-mail: shaabansalem@gmail.com [Department of Physics, Faculty of Science, Al Azhar University, Nasr City 11884, Cairo (Egypt); Abdel-Khalek, E.K. [Department of Physics, Faculty of Science, Al Azhar University, Nasr City 11884, Cairo (Egypt); Department of Physics, Faculty of Science, Jazan University (Saudi Arabia); Mohamed, E.A. [Department of Physics, Faculty of Science (Girl' s Branch), Al Azhar University, Nasr City, Cairo (Egypt); Department of Physics, Faculty of Science, Jazan University (Saudi Arabia); Farouk, M. [Department of Physics, Faculty of Science, Al Azhar University, Nasr City 11884, Cairo (Egypt); Department of Physics, Faculty of Science, Jazan University (Saudi Arabia)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer I report, for the first time, the effect of WO{sub 3} on Bi{sub 2}O{sub 3}, Li{sub 2}O, GeO{sub 2} and WO{sub 3} glasses through structural, optical, conductivity and dielectric studies. Black-Right-Pointing-Pointer Optical band gap E{sub op} for all types of electronic transitions, Urbach energy (E{sub r}), and refractive index determined. Black-Right-Pointing-Pointer The WO{sub 3} promotes as bitter constituent the reduction of W{sup 6+} to W{sup 5+} giving the bluish color. Black-Right-Pointing-Pointer Infrared spectra reveal characteristic GeO{sub 4}, GeO{sub 6}, Bi{sub 2}O{sub 3}, BiO{sub 6}, WO{sub 4} and WO{sub 6} units. Black-Right-Pointing-Pointer Based on ac and dc conductivity the conductivity increased and activation energies decreased with increase of WO{sub 3} content at all frequencies. - Abstract: Glasses in the system (65 - x)Bi{sub 2}O{sub 3}-15Li{sub 2}O-20GeO{sub 2}-xWO{sub 3} (where x = 2, 5 and 10 mol%) were prepared by normal melt quenching method. The change in density and molar volume in these glasses indicates the effect of WO{sub 3} on the glass structure. Fourier transform infrared (FT-IR) spectra show that these glasses are made up of GeO{sub 4}, GeO{sub 6}, BiO{sub 6}, BiO{sub 3}, WO{sub 4} and WO{sub 6} basic structural units. The structural units of BiO{sub 6}, GeO{sub 6} and WO{sub 6} increase with the increasing of WO{sub 3} content. The optical constants of these glasses are determined over a spectral range, providing the complex dielectric constant to be calculated. Higher values for the refractive index and dispersion are recorded due to the high polarizability of bismuth and tungsten ions. The values of the optical band gap E{sub g} for all types of electronic transitions and refractive index have been determined and discussed. The dc conductivity measured in the temperature range 423-623 K obeys Arrhenius law. The dielectric constant ({epsilon} Prime ), dielectric loss (tan {delta}) and

  19. Dependence of optical phase modulation on anchoring strength of dielectric shield wall surfaces in small liquid crystal pixels

    Science.gov (United States)

    Isomae, Yoshitomo; Shibata, Yosei; Ishinabe, Takahiro; Fujikake, Hideo

    2018-03-01

    We demonstrated that the uniform phase modulation in a pixel can be realized by optimizing the anchoring strength on the walls and the wall width in the dielectric shield wall structure, which is the needed pixel structure for realizing a 1-µm-pitch optical phase modulator. The anchoring force degrades the uniformity of the phase modulation in ON-state pixels, but it also keeps liquid crystals from rotating against the leakage of an electric field. We clarified that the optimal wall width and anchoring strength are 250 nm and less than 10-4 J/m2, respectively.

  20. Dielectric strength behaviour and mechanical properties of transparent insulation materials suitable to optical monitoring of partial discharges

    International Nuclear Information System (INIS)

    Lothongkam, Chaiyaporn

    2014-01-01

    A novel optical detection method for partial discharge in HV/EHV cable terminations has been proposed. Optical sensor fibres integrated into the HV equipment provide high sensitivity as well as immunity to electromagnetic interference and enable therefore on-line monitoring in electromagnetically noisy environment. The availability of optically transparent silicone rubbers that meet strict dielectric and mechanical criteria is a crucial prerequisite for the implementation of this method. The optically transparent silicone rubbers can be applied for the fabrication of a modern rubber stress cone as well as for the development of a new optical sensing element sensitive to PD activities. In this thesis, AC dielectric strength behaviour and mechanical properties of three types of commercially available silicone rubbers were investigated. One of the characterized silicone rubbers was a translucent type whereas the two others were optically transparent types, however with different chemical curing reactions. The measurements of tensile strength and elongation at break were carried out according to the ISO 37 standard. For investigation of the dielectric strength E b behaviour of the virgin and modified silicone rubbers, a new methodology was developed. It is, at the same time, highly reliable and efficient, saves time and reduces material consumption in comparison to previously reported methodologies. The key component of this methodology is a specifically developed test facility. Furthermore, the methodology comprises determinations for easy preparation and handling of high-quality test specimens. This test method provides various advantages over other methods that have previously been used for measurement of the fundamental quantity E b value of silicone rubbers. Both technical and economic demands are satisfied. The new facility also enables cost-effective routine tests in material research laboratories. The high quality of the obtained test results was verified by

  1. Two-dimensional optical simulation on a visible ray passing through inter-metal dielectric layers of CMOS image sensor device

    International Nuclear Information System (INIS)

    Lee, Wan-Gyu; Kim, Jun-Seok; Kim, Hee-Jeen; Kim, Sang-Young; Hwang, Sung-Bo; Lee, Jeong-Gun

    2005-01-01

    Two-dimensional optical simulation has been performed for investigating light propagation through a micro lens and inter-metal dielectric (IMD) layers in an Al and Cu back-end of line (BEOL) onto a Si photodiode, and its effects on the wave power, as well as optical carriers generated by a visible ray in the silicon substrate area, i.e. photodiode of a CMOS image sensor pixel. The number of optically generated carriers in an Al-BEOL has been compared to a Cu-BEOL. It is shown that more optical carriers are generated in the Cu-BEOL for the red color because a higher permittivity dielectric material like SiC is used in the Cu-BEOL to prevent Cu from diffusing into the dielectric material, resulting in higher optical loss in the higher- permittivity dielectric layers. Thus, the optical power density arriving in the silicon substrate is higher in the Al-BEOL than in the Cu-BEOL when the wavelength is blue (470 nm) or green (550 nm) in the visible ray spectrum. In conclusion, the structure of a Cu-BEOL in a CMOS image sensor has to be optimized for generating more optical carriers through lower-permittivity IMD materials or by reducing the permittivity difference between SiC (or SiN) and IMD materials, without deteriorating the capability as a barrier to Cu diffusion.

  2. Effect of amaranth on dielectric, thermal and optical properties of KDP single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chandran, Senthilkumar; Paulraj, Rajesh, E-mail: rajeshp@ssn.edu.in; Ramasamy, P.

    2017-01-15

    Bulk single crystals of pure and amaranth doped KDP were grown using point seed technique. Effect of amaranth doping on KDP crystals was analyzed using powder XRD, thermal analysis (TG/DTA), dielectric, photoconductivity and etching studies. The phase purity and crystallinity of pure and dye doped crystals were confirmed by powder X-ray diffraction analysis. It is observed from TG-DTA analysis that the decomposition point decreased while doping with amaranth. Dielectric constant and loss increases with increasing temperatures. The photoconductivity decreases with the increase of amaranth concentration. - Highlights: • Pure and amaranth doped KDP crystals grown from point seed technique. • The addition of amaranth changes the decomposition points of dye doped KDP crystals. • Dielectric constant is increased. • It shows positive photoconductivity.

  3. Quantum-optical input-output relations for dispersive and lossy multilayer dielectric plates

    International Nuclear Information System (INIS)

    Gruner, T.; Welsch, D.

    1996-01-01

    Using the Green-function approach to the problem of quantization of the phenomenological Maxwell theory, the propagation of quantized radiation through dispersive and absorptive multilayer dielectric plates is studied. Input-output relations are derived, with special emphasis on the determination of the quantum noise generators associated with the absorption of radiation inside the dielectric matter. The input-output relations are used to express arbitrary correlation functions of the outgoing field in terms of correlation functions of the incoming field and those of the noise generators. To illustrate the theory, photons at dielectric tunneling barriers are considered. It is shown that inclusion in the calculations of losses in the photonic band gaps may substantially change the barrier traversal times. copyright 1996 The American Physical Society

  4. Optical and dielectric studies of KH2PO4 crystal influenced by organic ligand of citric acid and l-valine: A single crystal growth and comparative study

    Directory of Open Access Journals (Sweden)

    Mohd Anis

    Full Text Available In the present study pure, citric acid (CA and l-valine (LV doped potassium dihydrogen phosphate (KDP crystals have been grown with the aim to investigate the nonlinear optical applications facilitated by UV–visible, third order nonlinear optical (TONLO and dielectric properties. The structural parameters of grown crystals have been confirmed by single crystal X-ray diffraction analysis. The enhancement in optical transparency of KDP crystal due to addition of CA and LV has been examined within 200–900 nm by means of UV–visible spectral analysis. In addition, the transmittance data have been used to evaluate the effect of dopants on reflectance, refractive index and extinction coefficient of grown crystals in the visible region. The Z-scan analysis has been performed at 632.8 nm to identify the nature of photoinduced nonlinear refraction and nonlinear absorption in doped KDP crystals. The influence of π-bonded ligand of dopant CA and LV on TONLO susceptibility (χ3, refractive index (n2 and absorption coefficient (β of KDP crystals has been evaluated to discuss laser assisted device applications. The decrease in dielectric constant and dielectric loss of KDP crystal due to addition of CA and LV has been explored using the temperature dependent dielectric studies. Keywords: Crystal growth, Nonlinear optical materials, UV–visible studies, Z-scan analysis, Dielectric studies

  5. Low threshold optical bistability and superluminal light propagation using a dielectric slab via inter-dot tunneling

    International Nuclear Information System (INIS)

    Taherzadeh, S; Nasehi, R; Mahmoudi, Mohammad

    2015-01-01

    The optical bistability (OB) behavior of a dielectric slab doped with quantum dot (QD) molecules is investigated in the presence of the inter-dot tunneling effect. It is shown that the threshold point of OB reduces by increasing inter-dot tunneling as well as by reducing the slab thickness. It is worth noting that the threshold of OB in a slab doped with QD molecules is smaller, by at least one order of magnitude, in respect to free QD molecules. We find that the inter-dot tunneling induces a negative group delay to the reflected pulse and it propagates in the superluminal region. Such simple control can be used in all optical switching. (paper)

  6. Synergistic effect of functionally active methacrylate polymer and ZnO nanoparticles on optical and dielectric properties

    International Nuclear Information System (INIS)

    Ilangovan, Pugazhenthi; Sakvai, Mohammed Safiullah; Kottur, Anver Basha

    2017-01-01

    A crucial need to design a functionally active polymer hybrid for the protection of material structure that are exposing to harmful Ultra Violet radiation (UV). In this paper a poly(pyridine-4-yl-methyl) methacrylate ZnO nanocomposite (PPyMMA/ZnO) was developed by in-situ solution polymerization. The X-ray diffraction (XRD) studies confirmed that the nanocomposite is homogeneous with good compatibility between the two counterparts. The morphological variation arises owing to the incorporation of OA-ZnO in the PPyMMA were observed by using electron microscope techniques. The thermal behaviour of PPyMMA and its ZnO nanocomposites were analysed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The dielectric properties of the polymer and its ZnO nanocomposites were studied over a wide range of temperature (30–300 °C) at frequency 100 KHz. An optical study was carried out to test the optical properties of PPyMMA/ZnO (2, 5 and 5%), which reveals that 2% ZnONPs loading exhibits an excellent UV shielding properties. - Highlights: • The PPyMMA/ZnO was prepared by in-situ solution polymerization. • The OA-ZnO were incorporated during the solution polymerization of PPyMMA. • The PPyMMA/ZnO nanocomposite exhibit an improved dielectric property. • The PPyMMA with OA-ZnO nanocomposite show an excellent UV-shielding.

  7. Effect of Co-60 gamma radiation on optical, dielectric and mechanical properties of strontium L-ascorbate hexahydrate NLO crystal

    Science.gov (United States)

    Dileep, M. S.; Suresh Kumar, H. M.

    2018-04-01

    A potentially useful nonlinear optical semi-organic single crystal of strontium L-ascorbate hexahydrate (SLAH) was grown by solution growth slow evaporation technique at room temperature. The grown crystal is semi transparent, yellowish in color with monoclinic crystal system having space group P21 and is stable up to 198 °C. Further, SLAH crystals were irradiated with gamma rays produced by 60Co with different doses of 10 KGy, 30 KGy and 50 KGy at room temperature and then studied the effect of gamma-rays on dielectric properties, optical absorption, microhardness and SHG efficiency. The absorption study reveals that the absorbance of the grown crystal is appeared to be low throughout the visible region with a lower cutoff wavelength of 277 nm and these parameters are not affected upon gamma irradiation. The luminescence intensity of the crystal is also not affected by the irradiation. There is noticeable changes were observed in dielectric properties and hardness of the materials for different doses of gamma irradiation. The second harmonic generation (SHG) efficiency of the grown crystal is 0.54 times that of the KDP crystal and is decreased moderately by increasing the dosage of gamma irradiation.

  8. Synergistic effect of functionally active methacrylate polymer and ZnO nanoparticles on optical and dielectric properties

    Energy Technology Data Exchange (ETDEWEB)

    Ilangovan, Pugazhenthi; Sakvai, Mohammed Safiullah; Kottur, Anver Basha, E-mail: kanverbasha@gmail.com

    2017-06-01

    A crucial need to design a functionally active polymer hybrid for the protection of material structure that are exposing to harmful Ultra Violet radiation (UV). In this paper a poly(pyridine-4-yl-methyl) methacrylate ZnO nanocomposite (PPyMMA/ZnO) was developed by in-situ solution polymerization. The X-ray diffraction (XRD) studies confirmed that the nanocomposite is homogeneous with good compatibility between the two counterparts. The morphological variation arises owing to the incorporation of OA-ZnO in the PPyMMA were observed by using electron microscope techniques. The thermal behaviour of PPyMMA and its ZnO nanocomposites were analysed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The dielectric properties of the polymer and its ZnO nanocomposites were studied over a wide range of temperature (30–300 °C) at frequency 100 KHz. An optical study was carried out to test the optical properties of PPyMMA/ZnO (2, 5 and 5%), which reveals that 2% ZnONPs loading exhibits an excellent UV shielding properties. - Highlights: • The PPyMMA/ZnO was prepared by in-situ solution polymerization. • The OA-ZnO were incorporated during the solution polymerization of PPyMMA. • The PPyMMA/ZnO nanocomposite exhibit an improved dielectric property. • The PPyMMA with OA-ZnO nanocomposite show an excellent UV-shielding.

  9. FD-TD modeling of 2-D dielectric waveguides for propagation and scattering of femtosecond optical solitons

    Science.gov (United States)

    Joseph, Rose; Goorjian, Peter; Taflove, Allen

    1993-01-01

    Experimentalists have produced all-optical switches capable of 100-fs responses. To adequately model such switches, nonlinear effects in optical materials (both instantaneous and dispersive) must be included. In principle, the behavior of electromagnetic fields in nonlinear dielectrics can be determined by solving Maxwell's equations subject to the assumption that the electric polarization has a nonlinear relation to the electric field. However, until our previous work, the resulting nonlinear Maxwell's equations have not been solved directly. Rather, approximations have been made that result in a class of generalized nonlinear Schrodinger equations (GNLSE) that solve only for the envelope of the optical pulses. In this paper, we present first-time calculations from the vector nonlinear Maxwell's equations of femtosecond soliton propagation and scattering, including carrier waves, in two-dimensional systems of dielectric waveguides exhibiting the Kerr and Raman quantum effects. We use the finite-difference time-domain (FD-TD) method in an extension of our 1-D work. There, in a fundamental innovation, we treated the linear and nonlinear convolutions for the electric polarization as new dependent variables. By differentiating these convolutions in the time domain, we derived an equivalent system of coupled, nonlinear second-order ODE's. These equations together with Maxwell's equations form the system that is solved to determine the electromagnetic fields in inhomogeneous nonlinear dispersive media. Backstorage in time is limited to only that needed by the time-integration algorithm for the ODE's, rather than that needed to store the time-history of the kernel functions of the convolutions (1000-10,000 time steps). Thus, a 2-D nonlinear optics model from Maxwell's equations is now feasible.

  10. Prospects for poor-man's cloaking with low-contrast all-dielectric optical elements

    DEFF Research Database (Denmark)

    Mortensen, Asger; Sigmund, Ole; Breinbjerg, Olav

    2009-01-01

    We discuss the prospects for low-contrast all-dielectric cloaking and offer a simple picture illustrating the basic obstacle for perfect cloaking without materials with an effective double-negative response. However, the same simple picture also gives directions for less perfect designs allowing ......-lens arrays perform in the opposite limit with L l...

  11. Nanostructured pyronin Y thin films as a new organic semiconductor: Linear/nonlinear optics, band gap and dielectric properties

    Energy Technology Data Exchange (ETDEWEB)

    Zahran, H.Y. [Metallurgical Lab.1, Nanoscience Laboratory for Environmental and Bio-medical Applications (NLEBA), Semiconductor Lab., Department of Physics, Faculty of Education, Ain Shams University, Roxy, 11757 Cairo (Egypt); Advanced Functional Materials & Optoelectronic Laboratory (AFMOL), Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha (Saudi Arabia); Yahia, I.S., E-mail: dr_isyahia@yahoo.com [Metallurgical Lab.1, Nanoscience Laboratory for Environmental and Bio-medical Applications (NLEBA), Semiconductor Lab., Department of Physics, Faculty of Education, Ain Shams University, Roxy, 11757 Cairo (Egypt); Advanced Functional Materials & Optoelectronic Laboratory (AFMOL), Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha (Saudi Arabia); Alamri, F.H. [Advanced Functional Materials & Optoelectronic Laboratory (AFMOL), Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha (Saudi Arabia)

    2017-05-15

    Pyronin Y dye (PY) is a kind of xanthene derivatives. Thin films of pyronin Y were deposited onto highly cleaned glass substrates using low-cost/spin coating technique. The structure properties of pyronin Y thin films with different thicknesses were investigated by using X-ray diffraction (XRD) and atomic force microscope (AFM). PY thin films for all the studied thicknesses have an amorphous structure supporting the short range order of the grain size. AFM supports the nanostructure with spherical/clusters morphologies of the investigated thin films. The optical constants of pyronin Y thin films for various thicknesses were studied by using UV–vis–NIR spectrophotometer in the wavelength range 350–2500 nm. The transmittance T(λ), reflectance R(λ) spectral and absorbance (abs(λ)) were obtained for all film thicknesses at room temperature and the normal light incident. These films showed a high transmittance in the wide scale wavelengths. For different thicknesses of the studied thin films, the optical band gaps were determined and their values around 2 eV. Real and imaginary dielectric constants, dissipation factor and the nonlinear optical parameters were calculated in the wavelengths to the range 300–2500 nm. The pyronin Y is a new organic semiconductor with a good optical absorption in UV–vis regions and it is suitable for nonlinear optical applications. - Highlights: • Pyronin Y (PY) nanostructured thin films were deposited by using spin coating technique. • XRD/AFM were used to study the structure of PY films. • The optical band gap was calculated on the basis of Tauc's model. • Linear/nonlinear optical parameters are calculated and interpreted via the applied optical theories. • PY thin films is a new organic semiconductor for its application in optoelectronic devices.

  12. Organic-inorganic hybrid optical foils with strong visible reflection, excellent near infrared-shielding ability and high transparency

    Science.gov (United States)

    Zhou, Yijie; Huang, Aibin; Zhou, Huaijuan; Ji, Shidong; Jin, Ping

    2018-03-01

    Research on functional flexible films has recently been attracting widespread attention especially with regards to foils, which can be designed artificially on the basis of the practical requirements. In this work, a foil with high visible reflection and a strong near infrared shielding efficiency was prepared by a simple wet chemical method. In the process of making this kind of optical foil, emulsion polymerization was first introduced to synthesize polymer opals, which were further compressed between two pieces of polyethylene terephthalate (PET) foil under polymer melting temperature to obtain a photonic crystal film with a strong reflection in the visible region to block blue rays. The following step was to coat a layer of the inorganic nano paint, which was synthesized by dispersing Cs-doped WO3 (CWO) nanoparticles homogenously into organic resin on the surface of the PET to achieve a high near infrared shielding ability. The final composite foil exhibited unique optical properties such as high visible reflectance (23.9%) to block blue rays, and excellent near infrared shielding efficiency (98.0%), meanwhile it still maintained a high transparency meaning that this foil could potentially be applied in energy-saving window films. To sum up, this study provides new insight into devising flexible hybrid films with novel optical properties, which could be further extended to prepare other optical films for potential use in automobile, architectural and other decorative fields.

  13. Electronic polarizability of light crude oil from optical and dielectric studies

    Science.gov (United States)

    George, A. K.; Singh, R. N.

    2017-07-01

    In the present paper we report the temperature dependence of density, refractive indices and dielectric constant of three samples of crude oils. The API gravity number estimated from the temperature dependent density studies revealed that the three samples fall in the category of light oil. The measured data of refractive index and the density are used to evaluate the polarizability of these fluids. Molar refractive index and the molar volume are evaluated through Lorentz-Lorenz equation. The function of the refractive index, FRI , divided by the mass density ρ, is a constant approximately equal to one-third and is invariant with temperature for all the samples. The measured values of the dielectric constant decrease linearly with increasing temperature for all the samples. The dielectric constant estimated from the refractive index measurements using Lorentz-Lorentz equation agrees well with the measured values. The results are promising since all the three measured properties complement each other and offer a simple and reliable method for estimating crude oil properties, in the absence of sufficient data.

  14. Effect of Gd3+ substitution on structural, magnetic, dielectric and optical properties of nanocrystalline CoFe2O4

    Science.gov (United States)

    Joshi, Seema; Kumar, Manoj; Chhoker, Sandeep; Kumar, Arun; Singh, Mahavir

    2017-03-01

    Nanoparticles of CoGdxFe2-xO4 with x=0.0, 0.03, 0.05, 0.07, 0.10 and 0.15 were synthesized by co-precipitation method. Gd3+ substitution effect on different properties of nanocrystalline CoFe2O4 has been studied. X-ray diffraction and Raman spectroscopy confirmed the formation of single phase cubic mixed spinel structure. Cation distribution has been proposed from Rietveld refined data. Mössbauer spectra at room temperature showed two ferrimagnetic Zeeman sextets with one superparamagnetic doublet. Mössbauer parameters suggested that Gd3+ ions occupy the octahedral site in CoFe2O4. Room temperature magnetic measurements exhibited that the saturation magnetization decreased from 91 emu/gm to 54 emu/gm for x=0.0 to 0.15 samples. The coercivity decreased from 1120 Oe to 340 Oe for x=0.0 to 0.07 samples and increased from 400 Oe to 590 Oe for x=0.10 and 0.15 samples, respectively. Raman analysis showed that the degree of inversion with Gd3+ substitution supporting the variation of coercivity. Electron spin resonance spectra revealed the dominancy of superexchange interactions in these samples. Optical band gap measurement suggested that all samples are indirect band gap materials and band gap has been decreased with Gd3+ substitution. Both dielectric constant and dielectric loss is found to decrease because of the decrease in hopping rate with the Gd3+ substitution for Fe3+ at the octahedral sites. Low dielectric loss suggested the applicability of Gd3+ doped CoFe2O4 nanoparticles for high frequency microwave device applications.

  15. Investigation of inorganic nonlinear optical potassium penta borate tetra hydrate (PPBTH) single crystals grown by slow evaporation method

    Science.gov (United States)

    Arivuselvi, R.; Babu, P. Ramesh

    2018-03-01

    Borates family crystals were plays vital role in the field of non linear optics (NLO) due to needs of wide range of applications. In this report, NLO crystals (potassium penta borate tetra hydrate (KB5H8O12) are grown by slow evaporation method at room temperature (28° C) and studied their physical properties. The harvested single crystals are transparent with the dimension of 12 × 10 × 6 mm3 and colourless. X-ray diffraction of single crystals reveals that the grown crystal belongs to orthorhombic system with non-centrosymmetric space group Pba2. All the absorbed functional groups are present in the order of inorganic compounds expect 1688 cm-1 because of water (Osbnd H sbnd O blending) molecule present in the pristine. Crystals show transparent in the entire visible region with 5.9 eV optical band gap and also it shows excellence in both second and third order nonlinear optical properties. Crystals can withstand upto 154 °C without any phase changes which is observed using thermal (TGA/DTA) analysis.

  16. Influence of energy and duration of laser pulses on stability of dielectric nanoparticles in optical trap

    International Nuclear Information System (INIS)

    Ho Quang Quy; Mai Van Luu; Hoang Dinh Hai

    2010-01-01

    In this article the gradient force of optical trap using two counter- propagating pulsed Gaussian beam and the Brownian motion in optical force field are investigated. The influence of the energy and duration time of optical pulsed Gaussian beams on stability of nano-particle in trap is simulated and discussed. (author)

  17. Structure and optical properties of several organic-inorganic hybrids containing corner-sharing chains of bismuth iodide octahedra.

    Science.gov (United States)

    Mitzi, D B; Brock, P

    2001-04-23

    Two organic-inorganic bismuth iodides of the form (H3N-R-NH3)BiI5 are reported, each containing long and relatively flexible organic groups, R. The norganic framework in each case consists of distorted BiI6 octahedra sharing cis vertexes to form zigzag chains. Crystals of (H3NC18H24S2NH3)BiI5 were grown from a slowly cooled ethylene glycol/2-butanol solution containing bismuth(III) iodide and AETH.2HI, where AETH = 1,6-bis[5'-(2' '-aminoethyl)-2'-thienyl]hexane. The new compound, (H2AETH)BiI5, adopts an orthorhombic (Aba2) cell with the lattice parameters a = 20.427(3) A, b = 35.078(5) A, c = 8.559(1) A, and Z = 8. The structure consists of corrugated layers of BiI5(2-) chains, with Bi-I bond lengths ranging from 2.942(3) to 3.233(3) A, separated by layers of the organic (H2AETH)(2+) cations. Crystals of the analogous (H3NC12H24NH3)BiI5 compound were also prepared from a concentrated aqueous hydriodic acid solution containing bismuth(III) iodide and the 1,12-dodecanediamine (DDDA) salt, DDDA.2HI. (H2DDDA)BiI5 crystallizes in an orthorhombic (Ibam) cell with a = 17.226(2) A, b = 34.277(4) A, c = 8.654(1) A, and Z = 8. The Bi-I bonds range in length from 2.929(1) to 3.271(1) A. While the inorganic chain structure is nearly identical for the two title compounds, as well as for the previously reported (H3NC6H12NH3)BiI5 [i.e., (H2DAH)BiI5] structure, the packing of the chains is strongly influenced by the choice of organic cation. Optical absorption spectra for thermally ablated thin films of the three organic-inorganic hybrids containing BiI5(2-) chains are reported as a function of temperature (25-290 K). The dominant long-wavelength feature in each case is attributed to an exciton band, which is apparent at room temperature and, despite the similar inorganic chain structure, varies in position from 491 to 541 nm (at 25 K).

  18. Spatially and temporally resolved detection of arsenic in a capillary dielectric barrier discharge by hydride generation high-resolved optical emission spectrometry

    Czech Academy of Sciences Publication Activity Database

    Burhenn, S.; Kratzer, Jan; Svoboda, Milan; Klute, F. D.; Michels, A.; Veža, D.; Franzke, J.

    2018-01-01

    Roč. 90, MAR (2018), s. 3424-3429 ISSN 0003-2700 R&D Projects: GA ČR GA17-04329S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * optical emission spectroscopy * arsenic hydride Subject RIV: CB - Analytical Chemistry , Separation OBOR OECD: Analytical chemistry Impact factor: 6.320, year: 2016

  19. Spatially and temporally resolved detection of arsenic in a capillary dielectric barrier discharge by hydride generation high-resolved optical emission spectrometry

    Czech Academy of Sciences Publication Activity Database

    Burhenn, S.; Kratzer, Jan; Svoboda, Milan; Klute, F. D.; Michels, A.; Veža, D.; Franzke, J.

    2018-01-01

    Roč. 90, MAR (2018), s. 3424-3429 ISSN 0003-2700 R&D Projects: GA ČR GA17-04329S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * optical emission spectroscopy * arsenic hydride Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 6.320, year: 2016

  20. Effect of Gd"3"+ substitution on structural, magnetic, dielectric and optical properties of nanocrystalline CoFe_2O_4

    International Nuclear Information System (INIS)

    Joshi, Seema; Kumar, Manoj; Chhoker, Sandeep; Kumar, Arun; Singh, Mahavir

    2017-01-01

    Nanoparticles of CoGd_xFe_2_−_xO_4 with x=0.0, 0.03, 0.05, 0.07, 0.10 and 0.15 were synthesized by co-precipitation method. Gd"3"+ substitution effect on different properties of nanocrystalline CoFe_2O_4 has been studied. X-ray diffraction and Raman spectroscopy confirmed the formation of single phase cubic mixed spinel structure. Cation distribution has been proposed from Rietveld refined data. Mössbauer spectra at room temperature showed two ferrimagnetic Zeeman sextets with one superparamagnetic doublet. Mössbauer parameters suggested that Gd"3"+ ions occupy the octahedral site in CoFe_2O_4. Room temperature magnetic measurements exhibited that the saturation magnetization decreased from 91 emu/gm to 54 emu/gm for x=0.0 to 0.15 samples. The coercivity decreased from 1120 Oe to 340 Oe for x=0.0 to 0.07 samples and increased from 400 Oe to 590 Oe for x=0.10 and 0.15 samples, respectively. Raman analysis showed that the degree of inversion with Gd"3"+ substitution supporting the variation of coercivity. Electron spin resonance spectra revealed the dominancy of superexchange interactions in these samples. Optical band gap measurement suggested that all samples are indirect band gap materials and band gap has been decreased with Gd"3"+ substitution. Both dielectric constant and dielectric loss is found to decrease because of the decrease in hopping rate with the Gd"3"+ substitution for Fe"3"+ at the octahedral sites. Low dielectric loss suggested the applicability of Gd"3"+ doped CoFe_2O_4 nanoparticles for high frequency microwave device applications. - Highlights: • Gd"3"+ ions were successfully added in to the spinel lattice of CoFe_2O_4. • Magnetic hysteresis loss is influenced by Gd"3"+ doping. • All doped samples exhibit normal dielectric dispersion behaviour of spinel ferrites. • UV–vis diffuse spectroscopy concludes band gap is reduced by Gd"3"+ doping.

  1. Effect of alkaline earth metal doping on thermal, optical, magnetic and dielectric properties of BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Bhushan, B; Das, D; Basumallick, A; Bandopadhyay, S K; Vasanthacharya, N Y

    2009-01-01

    Substrate-free pure-phase BiFeO 3 (BFO) nanoparticles doped with alkaline earth metals (Ba, Sr and Ca) have been synthesized by a sol-gel route and their thermal, optical, dielectric and magnetic properties are discussed. The characteristic structural phase transitions of BFO nanoparticles are found to occur at much lower temperatures. A reduction of the Neel temperature has been observed in the doped samples in comparison with the pristine one, whereas the band gap shows a reverse trend. Iron was found to be only in the Fe 3+ valence state in all the doped samples. Magnetoelectric coupling is seen in our samples. Weak ferromagnetism is observed at room temperature in all of the doped and undoped BFO nanoparticles with the largest value of coercive field ∼1.78 kOe and saturation magnetization ∼2.38 emu g -1 for Ba and Ca doped BFO nanoparticles, respectively.

  2. Effect of dilute magnetic ions on the optical, dielectric and ferroelectric properties of PZT at morphotopic phase boundary

    Science.gov (United States)

    Rao, T. Lakshmana; Pradhan, M. K.; Ramakrishna, P. V.; Dash, S.

    2018-05-01

    Modified-PZT ceramics with a formula Pb0.9Ni0.1[(Zr0.52Ti0.48)]1-xSnxO3 located near the morphotropic phase boundary (MPB) were prepared by conventional solid state process to investigate effects of dilute doping of Ni and Sn in different sites of PZT. The single phase structure of the series of samples has been identified by x-ray diffraction technique. The optical band gap has been obtained from the UV-Vis spectra and found to be shrinkage with doping. The detail dielectric and impedance studies are being carried out to investigate the conduction mechanism of the samples. A significant enhancement in the electric polarization is observed for the maximum Sn doping in a modified PZT.

  3. Synthesis and study of the optical properties of dielectric Bragg reflectors infiltrated with 6G-Rhodamine

    International Nuclear Information System (INIS)

    Gómez-Barojas, E; Aca-López, V; Luna-López, J A; Sánchez-Mora, E; Silva-González, R

    2014-01-01

    We report the study of the optical properties of 6G-Rhodamine (Rhd) infiltrated porous silicon dielectric Bragg reflectors (DBRs) with 31 constituent periods. The DBRs were obtained by an electrochemical anodizing process of Si in a two electrodes Teflon cell. The porosity was determined by gravimetric measurements on single Porous silicon (PSi) layers. Based on the characterization results of single layers the DBRs were synthesized. After anodizing, the DBRs were silanized with a 3-mercaptopropyltrimethoxysilane solution and functionalized with Rhd solutions at different concentrations. Cross section scanning electron micrographs show that the DBRs synthesis was successful. After each preparation step, Reflectance and Fluorescence (FL) spectra were recorded. These spectra show that as the Rhd concentration in solution is increased the stop band intensity as well as the FL intensity are enhanced due to constructive interference effects

  4. Outcome of temperature variation on sol-gel prepared CuO nanostructure properties (optical and dielectric)

    Energy Technology Data Exchange (ETDEWEB)

    Bibi, Maryam [Nano Synthesis Laboratory, Department of Physics, National University of Sciences and Technology, Islamabad (Pakistan); Javed, Qurat-ul-Ain, E-mail: quratulain@sns.nust.edu.pk [Nano Synthesis Laboratory, Department of Physics, National University of Sciences and Technology, Islamabad (Pakistan); Abbas, Hussain [Institute of Avionics & Aeronautics (IAA), Air University, Islamabad (Pakistan); Baqi, Sabah [Nano Synthesis Laboratory, Department of Physics, National University of Sciences and Technology, Islamabad (Pakistan)

    2017-05-01

    The optical and dielectric properties of Copper Oxide (CuO) have made it a fascinating material to be used in solar energy harvesting, gas sensing, optoelectronics and catalytical applications. Focusing on the cost-effectiveness of Sol-gel method, it is employed for nanostructured CuO production. Effect of changing temperature is observed on the formation mechanism of CuO and its properties. The temperature range of 300 °C–500 °C was used in annealing of samples to produce defect free CuO nanomaterial. Prepared material was investigated using phase characterization (X-ray diffraction ‘XRD’) technique, scanning electron microscopy (SEM), UV–Visible absorption spectroscopy and LCR meter. A structural change in prepared CuO was observed from cluster formation to Nano-fibrils by increase in annealing temperature. 11.99 nm–29.17 nm crystallites of CuO were attained by using Debye Scherer formula. A large band gap of 3.15 eV was achieved by increasing the annealing temperature upto 400 °C. For better solar energy harvest, wide band gapped CuO structures are proved to be functional and practical materials. The fabricated CuO nanostructures were found suitable to be used in devices for stabilizing circuit designs for sensitive appliances as well as micro electromechanical systems (mems). - Highlights: • CuO was synthesized by using sol gel method post growth annealing process. • XRD and SEM characterizations confirm the successful synthesis of CuO. • Change in morphology was observed with varying annealing temperature. • Improved optical and dielectric properties were observed.

  5. Construction tolerances for low loss, dielectric coated, metallic waveguide for transmission optical radiation

    International Nuclear Information System (INIS)

    Sandweiss, J.

    1984-08-01

    The transmission of radiation, in a specific mode of interest for the IFELA, past a symmetric step in dielectric coating thickness has been calculated. The result shows that the transmission loss depends on the quantity (s/D) 2 and vanishes to first order in the ratio of the step s to the guide aperture D. With the reasonable assumption that this feature holds for all forms of surface imperfections, the attenuation length due to imperfections has been estimated. It is found that rms surface roughness of approx. 0.1 μ m leads to attenuation lengths of 25 km or greater

  6. Electro-optic and dielectric properties of new binary ferroelectric and antiferroelectric liquid crystalline mixtures

    Czech Academy of Sciences Publication Activity Database

    Fitas, J.; Marzec, M.; Kurp, K.; Żurowska, M.; Tykarska, M.; Bubnov, Alexej

    2017-01-01

    Roč. 44, č. 9 (2017), s. 1468-1476 ISSN 0267-8292 R&D Projects: GA MŠk(CZ) LD14007; GA ČR GA15-02843S Grant - others:EU - ICT(XE) COST Action IC1208 Institutional support: RVO:68378271 Keywords : liquid crystals * ferroelectric and antiferroelectric phase * binary mixture * dielectric spectroscopy * switching time * tilt angle Subject RIV: JJ - Other Materials OBOR OECD: Nano-materials (production and properties) Impact factor: 2.661, year: 2016

  7. Contemporary dielectric materials

    CERN Document Server

    Saravanan, R

    2016-01-01

    This book deals with experimental results of the physical characterization of several important, dielectric materials of great current interest. The experimental tools used for the analysis of these materials include X-ray diffraction, dielectric measurements, magnetic measurements using a vibrating sample magnetometer, optical measurements using a UV-Visible spectrometer etc.

  8. Integrated Optical Mach-Zehnder Interferometer Based on Organic-Inorganic Hybrids for Photonics-on-a-Chip Biosensing Applications.

    Science.gov (United States)

    Bastos, Ana R; Vicente, Carlos M S; Oliveira-Silva, Rui; Silva, Nuno J O; Tacão, Marta; Costa, João P da; Lima, Mário; André, Paulo S; Ferreira, Rute A S

    2018-03-12

    The development of portable low-cost integrated optics-based biosensors for photonics-on-a-chip devices for real-time diagnosis are of great interest, offering significant advantages over current analytical methods. We report the fabrication and characterization of an optical sensor based on a Mach-Zehnder interferometer to monitor the growing concentration of bacteria in a liquid medium. The device pattern was imprinted on transparent self-patternable organic-inorganic di-ureasil hybrid films by direct UV-laser, reducing the complexity and cost production compared with lithographic techniques or three-dimensional (3D) patterning using femtosecond lasers. The sensor performance was evaluated using, as an illustrative example, E. coli cell growth in an aqueous medium. The measured sensitivity (2 × 10 -4 RIU) and limit of detection (LOD = 2 × 10 -4 ) are among the best values known for low-refractive index contrast sensors. Furthermore, the di-ureasil hybrid used to produce this biosensor has additional advantages, such as mechanical flexibility, thermal stability, and low insertion losses due to fiber-device refractive index mismatch (~1.49). Therefore, the proposed sensor constitutes a direct, compact, fast, and cost-effective solution for monitoring the concentration of lived-cells.

  9. Elaboration, structural, vibrational and optical investigation of a two-dimensional self-assembled organic–inorganic hybrid compound

    International Nuclear Information System (INIS)

    Dammak, T.; Boughzala, H.; Mlayah, A.; Abid, Y.

    2016-01-01

    Single crystals of a hybrid organic/inorganic material with the formula (C 4 N 3 H 16 )Cl[CuCl 4 ] were elaborated and studied by X-ray diffraction, and photoluminescence. The crystals consist of a self-assembled multilayer structure with a Pnam space group. The structure is built up from the staking of infinite two-dimensional layers of CuCl 6 corner-sharing octahedra, separated by organic (C 4 N 3 H 16 ) 3+ chains. Such a structure may be regarded as a multi quantum well system, in which CuCl 6 layers act as semiconductor wells and the organic molecules act as insulator barriers Furthermore, the room temperature IR and Raman spectra of the title compound were recorded and analyzed. For optical investigations, thin films have been prepared by spin-coating method from the ethanol solution of the material. Optical absorption spectra shows characteristic absorptions of CuCl-based layered perovskite centered at 300 and 380 nm, whereas the photoluminescence spectra shows a bleu intense emission around 420 nm, associated to radiative recombination of confined excitons in the CuCl 6 Quantum wells.

  10. The alkyl amines effect on the optical properties of inorganic perovskite quantum dot

    Science.gov (United States)

    Yang, Ya-Zhu; Chung, Shu-Ru

    2017-08-01

    Perovskite quantum dots (P-QDs) is a new kind of optoelectronic materials in recent years. Compared with organic perovskite QDs (MAPbX3), inorganic perovskite QDs (CsPbX3) have a better stability. Inorganic P-QDs can be prepared at low temperature. Those novel QDs can be applied in solar cells, light-emitting diodes (LEDs), display, and biolables. Typical synthesis process to prepare CsPbX3 QDs is used oleic acid (OA) and cesium carbonate (Cs2CO3) to form Cs-oleate complex first. Moreover, the oleylamine (OLA) and octadecene (ODE) are used as capping agents. Cs-oleate complex then reacts with PbX2 to form CsPbX3 QDs (reacts for 5 s). As we know that the CsPbBr3 QDs emits green light, and its emission wavelength can be tuned by adding Cland Iions to replace Brion. However, the reaction rate of CsPbX3 QDs is fast, and it is not easy to control the emission wavelength by particle size. In this study, we use the saturated alkyl amines with difference of carbon chain length such as dodecylamine (DDA), hexadecylamine (HDA), and octadecylamine (ODA) to prepare CsPbBr3 QDs. The result shows that the emission spectra for all samples range from 489 (ODA) to 514 nm (DDA), the full width at half-maximum (FWHM) is between 23 to 28 nm, the surface morphologies of all samples are nearly spherical, and the quantum yields (QYs) are higher up to 130 % (compared with R6G and the excitation wavelength is 450 nm). Based on emission spectra we can find that the emission peaks are fixed even under different excitation wavelength, imply that the particle size distribution of QDs is uniform. Moreover, the emission wavelength blue shifts with increasing carbon chain length of amines. The stability of alkyl amine-capped CsPbBr3 QDs is good, especially for DDA-capped sample. We also find that a small emission peak around 462 nm can be only observed for DDA-capped sample. Furthermore, this small peak also can be observed even prolong the reaction time to 10 min. The emission wavelengths of Cs

  11. UV/Vis visible optical waveguides fabricated using organic-inorganic nanocomposite layers.

    Science.gov (United States)

    Simone, Giuseppina; Perozziello, Gerardo

    2011-03-01

    Nanocomposite layers based on silica nanoparticles and a methacrylate matrix are synthesized by a solvent-free process and characterized in order to realize UV/Vis transparent optical waveguides. Chemical functionalization of the silica nanoparticles permits to interface the polymers and the silica. The refractive index, roughness and wettability and the machinability of the layers can be tuned changing the silica nanoparticle concentration and chemical modification of the surface of the nanoparticles. The optical transparency of the layers is affected by the nanoparticles organization between the organic chains, while it increased proportionally with respect to silica concentration. Nanocomposite layers with a concentration of 40 wt% in silica reached UV transparency for a wavelength of 250 nm. UV/Vis transparent waveguides were micromilled through nanocomposite layers and characterized. Propagation losses were measured to be around 1 dB cm(-1) at a wavelength of 350 nm.

  12. Optical orientation and alignment of excitons in ensembles of inorganic perovskite nanocrystals

    OpenAIRE

    Nestoklon, M. O.; Goupalov, S. V.; Dzhioev, R. I.; Ken, O. S.; Korenev, V. L.; Kusrayev, Yu. G.; Sapega, V. F.; de Weerd, C.; Gomez, L.; Gregorkiewicz, T.; Lin, Junhao; Suenaga, Kazutomo; Fujiwara, Yasufumi; Matyushkin, L. B.; Yassievich, I. N.

    2018-01-01

    We demonstrate the optical orientation and alignment of excitons in a two-dimensional layer of CsPbI$_3$ perovskite nanocrystals prepared by colloidal synthesis and measure the anisotropic exchange splitting of exciton levels in the nanocrystals. From the experimental data at low temperature (2K), we obtain the average value of anisotropic splitting of bright exciton states of the order of 120{\\mu}eV. Our calculations demonstrate that there is a significant contribution to the splitting due t...

  13. Spectral, structural, optical and dielectrical studies of UV irradiated Rose Bengal thin films prepared by spin coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Zeyada, H.M., E-mail: hzeyada@gmail.com [Department of Physics, Faculty of Science at New Damietta, University of Damietta, 34517 (Egypt); Youssif, M.I.; El-Ghamaz, N.A. [Department of Physics, Faculty of Science at New Damietta, University of Damietta, 34517 (Egypt); Aboderbala, M.E.O. [Department of Physics, Faculty of Science at New Damietta, University of Damietta, 34517 (Egypt); Department of Physics, Faculty of Science, AlJabl Al Gharbi University (Libya)

    2017-02-01

    Optical properties of pristine and UV irradiated Rose Bengal (RB) films have been investigated using transmittance and reflectance methods. The refractive index(n) and extinction coefficient (k) have been calculated from the absolute values of transmission and reflection spectrum. Single oscillator parameters and Drude model of free carrier absorption have been applied for analysis of the refractive index dispersion. Within the frame work of the band-to-band electron transitions theory; the fundamental absorption edge data were analyzed. Our results suggest that thickness of RB films has no effect on the absorption or the refractive indices in the investigated thicknesses range and within the experimental error. Structural transformation of films from amorphous to polycrystalline has been observed upon UV irradiation. Accordingly, the decreases of all of the absorption coefficient, the energy gap and the refractive index of RB films have been detected. Furthermore, the dependence of the optical functions on UV exposure times has been discussed based on the spectral distribution of the dielectric constant.

  14. Single-step in-situ synthesis and optical properties of ZnSe nanostructured dielectric nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Dey, Chirantan; Rahaman Molla, Atiar; Tarafder, Anal; Karmakar, Basudeb, E-mail: basudebk@cgcri.res.in [CSIR-Central Glass and Ceramic Research Institute, Glass Science and Technology Section, Glass Division, 196, Raja S. C. Mullick Road, 700032 Kolkata (India); Kr Mishra, Manish; De, Goutam [CSIR-Central Glass and Ceramic Research Institute, Nano-Structured Materials Division, 196, Raja S. C. Mullick Road, 700032 Kolkata (India); Goswami, Madhumita; Kothiyal, G. P. [Glass and Advanced Ceramics Division, Bhaba Atomic Research Centre, Trombay, 400085 Mumbai (India)

    2014-04-07

    This work provides the evidence of visible red photoluminescent light emission from ZnSe nanocrystals (NCs) grown within a dielectric (borosilicate glass) matrix synthesized by a single step in-situ technique for the first time and the NC sizes were controlled by varying only the concentration of ZnSe in glass matrix. The ZnSe NCs were investigated by UV-Vis optical absorption spectroscopy, Raman spectroscopy, and transmission electron microscopy (TEM). The sizes of the ZnSe NCs estimated from the TEM images are found to alter in the range of 2–53 nm. Their smaller sizes of the NCs were also calculated by using the optical absorption spectra and the effective mass approximation model. The band gap enlargements both for carrier and exciton confinements were evaluated and found to be changed in the range of 0–1.0 eV. The Raman spectroscopic studies showed blue shifted Raman peaks of ZnSe at 295 and 315 cm{sup −1} indicating phonon confinement effect as well as compressive stress effect on the surface atoms of the NCs. Red photoluminescence in ZnSe-glass nanocomposite reveals a broad multiple-peak structure due to overlapping of emission from NC size related electron-hole recombination (∼707 nm) and emissions from defects to traps, which were formed due to Se and Zn vacancies signifying potential application in photonics.

  15. Polar Mixing Optical Phonon Spectra in Wurtzite GaN Cylindrical Quantum Dots: Quantum Size and Dielectric Effects

    International Nuclear Information System (INIS)

    Zhang Li; Liao Jianshang

    2010-01-01

    The interface-optical-propagating (IO-PR) mixing phonon modes of a quasi-zero-dimensional (QoD) wurtzite cylindrical quantum dot (QD) structure are derived and studied by employing the macroscopic dielectric continuum model. The analytical phonon states of IO-PR mixing modes are given. It is found that there are two types of IO-PR mixing phonon modes, i.e. ρ-IO/z-PR mixing modes and the z-IO/ρ-PR mixing modes existing in QoD wurtzite QDs. And each IO-PR mixing modes also have symmetrical and antisymmetrical forms. Via a standard procedure of field quantization, the Froehlich Hamiltonians of electron-(IO-PR) mixing phonons interaction are obtained. Numerical calculations on a wurtzite GaN cylindrical QD are performed. The results reveal that both the radial-direction size and the axial-direction size as well as the dielectric matrix have great influence on the dispersive frequencies of the IO-PR mixing phonon modes. The limiting features of dispersive curves of these phonon modes are discussed in depth. The phonon modes 'reducing' behavior of wurtzite quantum confined systems has been observed obviously in the structures. Moreover, the degenerating behaviors of the IO-PR mixing phonon modes in wurtzite QoD QDs to the IO modes and PR modes in wurtzite Q2D QW and Q1D QWR systems are analyzed deeply from both of the viewpoints of physics and mathematics. (interdisciplinary physics and related areas of science and technology)

  16. Band Alignment and Optical Properties of (ZrO20.66(HfO20.34 Gate Dielectrics Thin Films on p-Si (100

    Directory of Open Access Journals (Sweden)

    Dahlang Tahir

    2011-11-01

    Full Text Available (ZrO20.66(HfO20.34 dielectric films on p-Si (100 were grown by atomic layer deposition method, for which the conduction band offsets, valence band offsets and band gaps were obtained by using X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. The band gap, valence and conduction band offset values for (ZrO20.66(HfO20.34 dielectric thin film, grown on Si substrate were about 5.34, 2.35 and 1.87 eV respectively. This band alignment was similar to that of ZrO2. In addition, The dielectric function ε (k, ω, index of refraction n and the extinction coefficient k for the (ZrO20.66(HfO20.34 thin films were obtained from a quantitative analysis of REELS data by comparison to detailed dielectric response model calculations using the QUEELS-ε (k,ω-REELS software package. These optical properties are similar with ZrO2 dielectric thin films.

  17. Optical force and torque on a dielectric Rayleigh particle by a circular Airy vortex beam

    Science.gov (United States)

    Chen, Musheng; Huang, Sujuan; Shao, Wei; Liu, Xianpeng

    2018-03-01

    Optical force and torque exerted on the Rayleigh particles by tightly focused circularly polarized circular Airy vortex beams (CAVB) in the far field are studied in this paper. The relation between parameters of circularly polarized CAVB and the trapping properties is numerically analyzed based on Rayleigh models and the Debye diffraction theory. The results show that both the high refractive index and low refractive index particles can be fully stably trapped in three dimensions by circularly polarized CAVB. The parameters of circularly polarized CAVB greatly affect the optical force. The longitudinal and transverse gradient force increase with the increase of decay factor and scaling factor, and decrease with the increase of the radius of the first primary ring and topological charges. The positions of the longitudinal stable equilibrium move toward the high numerical aperture lens when the scaling factor and the radius of the primary ring increase. The trapping range is broadened with the decrease of scaling factor. The optical orbital torque (OOT) of circularly polarized CAVB has circular symmetry and remains positive or negative. With the increase of topological charges, the peak value of OOT first increases and then decreases after reaches a maximum. These results are useful for optical trapping, optical levitation and particle acceleration.

  18. Measurements of thermodynamic and optical properties of selected aqueous organic and organic-inorganic mixtures of atmospheric relevance.

    Science.gov (United States)

    Lienhard, Daniel M; Bones, David L; Zuend, Andreas; Krieger, Ulrich K; Reid, Jonathan P; Peter, Thomas

    2012-10-11

    Atmospheric aerosol particles can exhibit liquid solution concentrations supersaturated with respect to the dissolved organic and inorganic species and supercooled with respect to ice. In this study, thermodynamic and optical properties of sub- and supersaturated aqueous solutions of atmospheric interest are presented. The density, refractive index, water activity, ice melting temperatures, and homogeneous ice freezing temperatures of binary aqueous solutions containing L(+)-tartaric acid, tannic acid, and levoglucosan and ternary aqueous solutions containing levoglucosan and one of the salts NH(4)HSO(4), (NH(4))(2)SO(4), and NH(4)NO(3) have been measured in the supersaturated concentration range for the first time. In addition, the density and refractive index of binary aqueous citric acid and raffinose solutions and the glass transition temperatures of binary aqueous L(+)-tartaric acid and levoglucosan solutions have been measured. The data presented here are derived from experiments on single levitated microdroplets and bulk solutions and should find application in thermodynamic and atmospheric aerosol models as well as in food science applications.

  19. An optically transparent and flexible memory with embedded gold nanoparticles in a polymethylsilsesquioxane dielectric

    International Nuclear Information System (INIS)

    Ooi, P.C.; Aw, K.C.; Gao, W.; Razak, K.A.

    2013-01-01

    In this work, we demonstrated a simple fabrication route towards an optically transparent and flexible memory device. The device is simple and consists of a metal/insulator/semiconductor structure; namely MIS. The preliminary MIS study with gold nanoparticles embedded between the polymethylsilsesquioxane layers was fabricated on p-Si substrate and the capacitance versus voltage measurements confirmed the charge trapped capability of the fabricated MIS memory device. Subsequently, an optically transparent and flexible MIS memory device made from indium–tin-oxide coated polyethylene terephthalate substrate and pentacene was used to replace the opaque p-Si substrate as the active layer. Current versus voltage (I–V) plot of the transparent and flexible device shows the presence of hysteresis. In an I–V plot, three distinct regions have been identified and the transport mechanisms are explained. The fabricated optically transparent and mechanically flexible MIS memory device can be programmed and erased multiple times, similar to a flash memory. Mechanical characterization to determine the robustness of the flexible memory device was also conducted but failed to establish any relationship in this preliminary work as the effect was random. Hence, more work is needed to understand the reliability of this device, especially when they are subjected to mechanical stress. - Highlights: ► An optically transparent and mechanically flexible memory is presented. ► Electrical characteristics show reprogrammable memory similar to flash memory. ► Transport mechanisms are proposed and explained. ► Mechanical bending tests are conducted

  20. Demonstration of optical vortex propagation in on-chip rectangular dielectric waveguides

    DEFF Research Database (Denmark)

    Lyubopytov, Vladimir S.; Chipouline, Arkadi; Sokolovskii, Grigorii S.

    2017-01-01

    Orbital angular momentum (OAM) of light provides an additional degree of freedom for multiplexing the data streams in optical communications, increasing further the channel capacity [1]. Applications of OAM for both classical data transmission [2] and quantum information [3] have been demonstrated...

  1. An optically transparent and flexible memory with embedded gold nanoparticles in a polymethylsilsesquioxane dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Ooi, P.C. [Mechanical Engineering, The University of Auckland (New Zealand); Aw, K.C., E-mail: k.aw@auckland.ac.nz [Mechanical Engineering, The University of Auckland (New Zealand); Gao, W. [Chemical and Materials Engineering, The University of Auckland (New Zealand); Razak, K.A. [School of Materials and Mineral Resources Engineering, Universiti Sains (Malaysia); NanoBiotechnology Research and Innovation, INFORMM, Universiti Sains (Malaysia)

    2013-10-01

    In this work, we demonstrated a simple fabrication route towards an optically transparent and flexible memory device. The device is simple and consists of a metal/insulator/semiconductor structure; namely MIS. The preliminary MIS study with gold nanoparticles embedded between the polymethylsilsesquioxane layers was fabricated on p-Si substrate and the capacitance versus voltage measurements confirmed the charge trapped capability of the fabricated MIS memory device. Subsequently, an optically transparent and flexible MIS memory device made from indium–tin-oxide coated polyethylene terephthalate substrate and pentacene was used to replace the opaque p-Si substrate as the active layer. Current versus voltage (I–V) plot of the transparent and flexible device shows the presence of hysteresis. In an I–V plot, three distinct regions have been identified and the transport mechanisms are explained. The fabricated optically transparent and mechanically flexible MIS memory device can be programmed and erased multiple times, similar to a flash memory. Mechanical characterization to determine the robustness of the flexible memory device was also conducted but failed to establish any relationship in this preliminary work as the effect was random. Hence, more work is needed to understand the reliability of this device, especially when they are subjected to mechanical stress. - Highlights: ► An optically transparent and mechanically flexible memory is presented. ► Electrical characteristics show reprogrammable memory similar to flash memory. ► Transport mechanisms are proposed and explained. ► Mechanical bending tests are conducted.

  2. Design and optimization of carbon-nanotube-material/dielectric hybrid nonlinear optical waveguides

    International Nuclear Information System (INIS)

    Zhao, Xin; Zheng, Zheng; Lu, Zhiting; Zhu, Jinsong; Zhou, Tao

    2011-01-01

    The nonlinear optical characteristics of highly nonlinear waveguides utilizing carbon nanotube composite materials are investigated theoretically. The extremely high nonlinearity and relatively high loss of the carbon nanotube materials are shown to greatly affect the performance of such waveguides for nonlinear optical applications, in contrast to waveguides using conventional nonlinear materials. Different configurations based on applying the carbon nanotube materials to the popular ridge and buried waveguides are thoroughly studied, and the optimal geometries are derived through simulations. It is shown that, though the nonlinear coefficient is often huge for these waveguides, the loss characteristics can significantly limit the maximum achievable accumulated nonlinearity, e.g. the maximum nonlinear phase shift. Our results suggest that SOI-based high-index-contrast, carbon nanotube cladding waveguides, rather than the currently demonstrated low-contrast waveguides, could hold the promise of achieving significantly higher accumulated nonlinearity

  3. Sequential and selective localized optical heating in water via on-chip dielectric nanopatterning.

    Science.gov (United States)

    Morsy, Ahmed M; Biswas, Roshni; Povinelli, Michelle L

    2017-07-24

    We study the use of nanopatterned silicon membranes to obtain optically-induced heating in water. We show that by varying the detuning between an absorptive optical resonance of the patterned membrane and an illumination laser, both the magnitude and response time of the temperature rise can be controlled. This allows for either sequential or selective heating of different patterned areas on chip. We obtain a steady-state temperature of approximately 100 °C for a 805.5nm CW laser power density of 66 µW/μm 2 and observe microbubble formation. The ability to spatially and temporally control temperature on the microscale should enable the study of heat-induced effects in a variety of chemical and biological lab-on-chip applications.

  4. A geometrical optics polarimetric bidirectional reflectance distribution function for dielectric and metallic surfaces.

    Science.gov (United States)

    Hyde, M W; Schmidt, J D; Havrilla, M J

    2009-11-23

    A polarimetric bidirectional reflectance distribution function (pBRDF), based on geometrical optics, is presented. The pBRDF incorporates a visibility (shadowing/masking) function and a Lambertian (diffuse) component which distinguishes it from other geometrical optics pBRDFs in literature. It is shown that these additions keep the pBRDF bounded (and thus a more realistic physical model) as the angle of incidence or observation approaches grazing and better able to model the behavior of light scattered from rough, reflective surfaces. In this paper, the theoretical development of the pBRDF is shown and discussed. Simulation results of a rough, perfect reflecting surface obtained using an exact, electromagnetic solution and experimental Mueller matrix results of two, rough metallic samples are presented to validate the pBRDF.

  5. Optical Properties of Moderately-Absorbing Organic and Mixed Organic/Inorganic Particles at Very High Humidities

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Tami C; Rood, Mark J; Brem, Benjamin T; Mena-Gonzalez, Francisco C; Chen, Yanju

    2012-04-16

    Relative humidity (RH) affects the water content of an aerosol, altering its ability to scatter and absorb light, which is important for aerosol effects on climate and visibility. This project involves in situ measurement and modeling of aerosol optical properties including absorption, scattering and extinction at three visible wavelengths (467, 530, 660 nm), for organic carbon (OC) generated by pyrolysis of biomass, ammonium sulfate and sodium chloride, and their mixtures at controlled RH conditions. Novel components of this project include investigation of: (1) Changes in all three of these optical properties at scanned RH conditions; (2) Optical properties at RH values up to 95%, which are usually extrapolated instead of measured; and (3) Examination of aerosols generated by the pyrolysis of wood, which is representative of primary atmospheric organic carbon, and its mixture with inorganic aerosol. Scattering and extinction values were used to determine light absorption by difference and single scattering albedo values. Extensive instrumentation development and benchmarking with independently measured and modeled values were used to obtain and evaluate these new results. The single scattering albedo value for a dry absorbing polystyrene microsphere benchmark agreed within 0.02 (absolute value) with independently published results at 530 nm. Light absorption by a nigrosin (sample light-absorbing) benchmark increased by a factor of 1.24 +/-0.06 at all wavelengths as RH increased from 38 to 95%. Closure modeling with Mie theory was able to reproduce this increase with the linear volume average (LVA) refractive index mixing rule for this water soluble compound. Absorption by biomass OC aerosol increased by a factor of 2.1 +/- 0.7 and 2.3 +/- 1.2 between 32 and 95% RH at 467 nm and 530 nm, but there was no detectable absorption at 660 nm. Additionally, the spectral dependence of absorption by OC that was observed with filter measurements was confirmed qualitatively

  6. Growth, structural, thermal, dielectric and nonlinear optical properties of potassium hexachloro cadmate (IV) a novel single crystal

    Science.gov (United States)

    Umarani, P.; Jagannathan, K.

    2018-02-01

    The Potassium hexachloro cadmate (IV) (PHC) single crystal was grown from the aqueous of the solution by a controlled evaporation method. Single crystal XRD solved the structure. FTIR is used to identify the functional groups of grown crystal. The UV-Vis-NIR spectrometer was used to find out the UV cut off region and to calculate the optical band gap of the Potassium hexachloro cadmate (IV) single crystal. The EDAX spectrum has been used to identify the compounds present in title compound. The TG-DTA profile shows the thermal stability of the grown crystal of Potassium hexachloro cadmate (IV). The Vicker's hardness measurement was used to calculate the material hardness of the title compound. The dielectric loss and constant varied with frequencies and activation energy is also calculated. The solid state parameters like plasma energy, Penn gap, Fermi energy, electronic polarizability using Penn analysis and Clausius-Mossotti equation were also calculated for the title compound. The Z-scan technique is used to calculate the third order nonlinear susceptibility of a real and imaginary part.

  7. Metal carbonyl vapor generation coupled with dielectric barrier discharge to avoid plasma quench for optical emission spectrometry.

    Science.gov (United States)

    Cai, Yi; Li, Shao-Hua; Dou, Shuai; Yu, Yong-Liang; Wang, Jian-Hua

    2015-01-20

    The scope of dielectric barrier discharge (DBD) microplasma as a radiation source for optical emission spectrometry (OES) is extended by nickel carbonyl vapor generation. We proved that metal carbonyl completely avoids the extinguishing of plasma, and it is much more suitable for matching the DBD excitation and OES detection with respect to significant DBD quenching by concomitant hydrogen when hydride generation is used. A concentric quartz UV reactor allows sample solution to flow through the central channel wherein to efficiently receive the uniformly distributed UV irradiation in the confined cylindrical space between the concentric tubes, which facilitates effective carbonyl generation in a nickel solution. The carbonyl is transferred into the DBD excitation chamber by an argon stream for nickel excitation, and the characteristic emission of nickel at 232.0 nm is detected by a charge-coupled device (CCD) spectrometer. A 1.0 mL sample solution results in a linear range of 5-100 μg L(-1) along with a detection limit of 1.3 μg L(-1) and a precision of 2.4% RSD at 50 μg L(-1). The present DBD-OES system is validated by nickel in certified reference materials.

  8. Race for novel high-index all-dielectric and hybrid metal-dielectric nanophotonic materials: Pit-stop optical tests

    Science.gov (United States)

    Kudryashov, S. I.; Saraeva, I. N.; Ivanova, A. K.; Kudryavtseva, A. D.; Tchiernega, N. V.; Ionin, A. A.; Kuchmizhak, A. A.; Zayarny, D. A.

    2017-09-01

    Magnetic dipolar Mie-resonance of nanodiamonds supports their highly-efficient stimulated low-frequency Raman scattering via nanosecond laser excitation of their fundamental breathing mode, with strong additional plasmonic enhancement of the Raman conversion efficiency upon ablative capping of the resonant nanodiamond core by a silver nanoshell with a broad overlapping electrical dipolar Mie-resonance. Also, crystalline selenium nanoparticles, exhibiting the high refractive index in the visible/near-IR ranges, were demonstrated as promising all-dielectric sensing building nanoblocks in nanophotonics.

  9. Time-and-frequency domains approach to data processing in multiwavelength optical scatterometry of dielectric gratings

    KAUST Repository

    Granet, Gérard

    2013-01-01

    This paper focuses on scatterometry problems arising in lithography production of periodic gratings. Namely, the paper introduces a theoretical and numerical-modeling-oriented approach to scatterometry problems and discusses its capabilities. The approach allows for reliable detection of deviations in gratings\\' critical dimensions (CDs) during the manufacturing process. The core of the approach is the one-to-one correspondence between the electromagnetic (EM) characteristics and the geometric/material properties of gratings. The approach is based on highly accurate solutions of initial boundary-value problems describing EM waves\\' interaction on periodic gratings. The advantage of the approach is the ability to perform simultaneously and interactively both in frequency and time domains under conditions of possible resonant scattering of EM waves by infinite or finite gratings. This allows a detection of CDs for a wide range of gratings, and, thus is beneficial for the applied scatterometry. (C) 2013 Optical Society of America

  10. Time-and-frequency domains approach to data processing in multiwavelength optical scatterometry of dielectric gratings

    KAUST Repository

    Granet, Gé rard; Melezhik, Petr N.; Sirenko, Kostyantyn; Yashina, Nataliya P.

    2013-01-01

    This paper focuses on scatterometry problems arising in lithography production of periodic gratings. Namely, the paper introduces a theoretical and numerical-modeling-oriented approach to scatterometry problems and discusses its capabilities. The approach allows for reliable detection of deviations in gratings' critical dimensions (CDs) during the manufacturing process. The core of the approach is the one-to-one correspondence between the electromagnetic (EM) characteristics and the geometric/material properties of gratings. The approach is based on highly accurate solutions of initial boundary-value problems describing EM waves' interaction on periodic gratings. The advantage of the approach is the ability to perform simultaneously and interactively both in frequency and time domains under conditions of possible resonant scattering of EM waves by infinite or finite gratings. This allows a detection of CDs for a wide range of gratings, and, thus is beneficial for the applied scatterometry. (C) 2013 Optical Society of America

  11. One-step shell polymerization of inorganic nanoparticles and their applications in SERS/nonlinear optical imaging, drug delivery, and catalysis.

    Science.gov (United States)

    Liu, Tzu-Ming; Yu, Jiashing; Chang, C Allen; Chiou, Arthur; Chiang, Huihua Kenny; Chuang, Yu-Chun; Wu, Cheng-Han; Hsu, Che-Hao; Chen, Po-An; Huang, Chih-Chia

    2014-07-07

    Surface functionalized nanoparticles have found their applications in several fields including biophotonics, nanobiomedicine, biosensing, drug delivery, and catalysis. Quite often, the nanoparticle surfaces must be post-coated with organic or inorganic layers during the synthesis before use. This work reports a generally one-pot synthesis method for the preparation of various inorganic-organic core-shell nanostructures (Au@polymer, Ag@polymer, Cu@polymer, Fe3O4@polymer, and TiO2@polymer), which led to new optical, magnetic, and catalytic applications. This green synthesis involved reacting inorganic precursors and poly(styrene-alt-maleic acid). The polystyrene blocks separated from the external aqueous environment acting as a hydrophobic depot for aromatic drugs and thus illustrated the integration of functional nanoobjects for drug delivery. Among these nanocomposites, the Au@polymer nanoparticles with good biocompatibility exhibited shell-dependent signal enhancement in the surface plasmon resonance shift, nonlinear fluorescence, and surface-enhanced Raman scattering properties. These unique optical properties were used for dual-modality imaging on the delivery of the aromatic photosensitizer for photodynamic therapy to HeLa cells.

  12. [Study on Square Super-Lattice Pattern with Surface Discharge in Dielectric Barrier Discharge by Optical Emission Spectra].

    Science.gov (United States)

    Niu, Xue-jiao; Dong, Li-fang; Liu, Ying; Wang, Qian; Feng, Jian-yu

    2016-02-01

    Square super-lattice pattern with surface discharge consisting of central spots and dim spots is firstly observed in the mixture of argon and air by using a dielectric barrier discharge device with water electrodes. By observing the image, it is found that the central spot is located at the centriod of its surrounding four dim spots. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The brightness of the central spot and is quite different from that of the dim spot, which indicates that the plasma states of the central spot and the dim spot may be differentiated. The optical emission spectrum method is used to further study the several plasma parameters of the central spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --> B³ IIg) are measured, from which the molecule vibration temperatures of the central spot and the dim spot are calculated respectively. The broadening of spectral line 696.57 nm (2P₂-->1S₅) is used to study the electron densities of the central spot and the dim spot. It is found that the molecule vibration temperature and electron density of the dim spot are higher than those of the central spot in the same argon content The molecule vibration temperature and electron density of the central spot and the dim spot increase with the argon content increasing from 90% to 99.9%. The surface discharge induced by the volume discharge (VD) has the determinative effect on the formation of the dim spot The experimental results above play an important role in studying the formation mechanism of surface discharg&of square super-lattice pattern with surface discharge. In addition, the studies exert an influence on the application of surface discharge and volume discharge in different fields.

  13. Structural, optical and dielectric properties of transition metal (MFe2O4; M = Co, Ni and Zn) nanoferrites

    Science.gov (United States)

    Chand, Prakash; Vaish, Swapnil; Kumar, Praveen

    2017-11-01

    In the present work, transition metal spinel ferrite (MFe2O4; M = Co, Ni, Zn) nanostructures synthesized by chemical co-precipitation method. XRD analysis confirms the formation of cubic spinel-type structure with space group Fd3m and the average crystallite size calculated by Scherrer's formula found to be in 9-14 nm range. Scanning electron microscopy was used to study surface morphology of the samples. Moreover, Raman and PL spectra also confirm the formation of the cubic structure. The Raman spectra measured on cobalt, nickel and zinc ferrite revealed a larger number of phonon bands than expected for the cubic spinel structure. The calculated optical energy band gaps, obtained by Tauc's relation from UV-Vis absorption spectra are found to be as 2.44, 3.54 and 3.25 eV for CoFe2O4, NiFe2O4&ZnFe2O, respectively. The analysis of the complex impedance spectra of all ferrites samples shows the presence of one semicircular arc at all selected temperatures, signifying a key role of the grain boundary contribution. The dielectric constants (ε ‧) were measured in the frequency range from 10 Hz to 5 MHz at different temperatures and is found to be decreased suddenly with an increase in frequency and maintain a steady state or constant at higher frequencies for all the three samples. The AC conductivity is found to be increased with frequency and temperature of all the three samples which is explained on the basis of Koop's phenomenological theory.

  14. Optical confinement and light guiding in high dielectric contrast materials systems

    Science.gov (United States)

    Foresi, James S.

    A study of silicon photonic devices, including waveguides and microcavities, is presented in this thesis. The high index difference of Silicon-On-Insulator materials is used to design submicron devices capable of light localization and routing. Losses due to interface roughness between the high and low index materials are measured to be 40dB/cm. An analysis of lithographically induced interface roughness is performed and a method for evaluating nanometer-scale roughness is presented. High index differences lead to compact bends and power splitters. Bends of 2.0μm radius are measured to have losses less than 0.5dB. Splitting angles of 5o with losses less than 1.5dB are demonstrated. The bends and splitters are the most compact devices of their kind. The design, fabrication and analysis of two light confining devices in the SOI system are presented: photonic band gap (PBG) and microdisk microcavities. A PBG waveguide microcavity with minimum dimensions of 0.10μm is fabricated and transmission measurements reveal cavity Q's of 265, a resonant wavelength of 1564nm, and a modal volume of 0.27/mu m3. This is the first demonstration of PBG resonance at optical frequencies. The PBG microcavity volume is two orders of magnitude smaller than has been achieved in other microcavity devices. Microdisk and microring resonators are demonstrated. A waveguide-coupled microring is shown to operate as a channel dropping filter with Q's of 250 and a free spectral range of 25nm. The application of the microcavity devices to spontaneous emission control of erbium-doped silicon is analyzed. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

  15. Radiation induced changes of optical, electrical and mechanical properties of glasses, dielectrics and semiconductors

    International Nuclear Information System (INIS)

    Adawi, M.A.

    2006-01-01

    This work is concerned with investigating the influence of ionizing radiation on different materials. Concretely, the change of their physical characteristics such as, the electrical resistivity, the optical density, the thermoluminescence spectra, the microhardness etc. The investigated materials are: polyethylene, glasses containing U 3 O 8 , Na 2 O and K 2 O, polyvinyl alcohol containing Ni 2 SO 4 , CoCl 2 , CuSO 4 and Cu (CH 3 COO) 2 , polymer Pb 2 O 3 /composite, germanium sulphur alloy, synthetic and natural diamond, nickel chromium steel and silicon. Irradiation is carried out in neutron fields of 10 5 -10 14 neutron/cm 2 , gamma radiation in the dose range 10 2 -10 6 Gy. and swift heavy ions of energy 1 MeV/amu fluence range 10 8 -10 16 ion/cm 2 . The possibility of working out dosimetric devices (using the above mentioned materials) possessing accurate and well expressed metrical characteristics for detecting different sorts of radiation is investigated. The optimum conditions of using these dosimeters (under different thermodynamic conditions and absolute values of registered radiation) are determined. The process of defect formation and evolution in silicon single crystal and diamond irradiated with swift heavy ions is studied. The influence of high-energy heavy ions on the surface structure of nickel chromium steel is investigated. The formation of thermally stable conducting layers at the far depth of the boron projective range in silicon irradiated with swift boron ions is confirmed. Irradiation of nickel chromium steel with xenon ions lead to the change of the elemental composition of the irradiated surface. For the case of diamond semiconductor single crystal irradiated with high-energy xenon or krypton ions possessing energy 1 MeV/nucleon, the track formation is observed for the first time. The track formation criteria are established. A model characterizing the interaction of high-energy heavy ions with diamond is introduced. Such model is found

  16. Influence of ionizing radiation on optical hardness of transparent dielectrics to action of huge intensity laser light

    International Nuclear Information System (INIS)

    Bedilov, M.R.; Khalilov, R.A.

    2006-01-01

    Full text: This paper presents results of researches of optical hardness of γ -irradiated with doze 10 4 - 10 9 rad alkali-silicate (K, GLS, LGS) and quartz (KU, KV, KSG) glasses against influence of radiation neodymium laser with intensity q = 0,1-1000 GWt/cm 2 . It is observed, that the laser produces damage of surface and volume of investigated glasses before and after γ-irradiation. This damage has threshold character and is always accompanied by a bright luminescence of plasma. Definition of threshold values of intensity superficial q s and volumetric q d laser produced damage was made by the complex method - fixing the moment of damage of transparent dielectric by simultaneous registration of the laser impulse which has passed through plasma of breakdown, mass-charge spectrum of ions of plasma and measuring the energy falling on the glass, and of penetrated and mirror-image radiations; and by optical microscopy. This method of research of influence γ-induced in transparent dielectric radiating defects on its optical stability against influence of laser radiation allows not only to define values q s and q d in the investigated interval of dozes, but also to investigate in details physical phenomena taking place in this process of interaction. On the basis of the received data quantitative characteristics of optical durability of the investigated glasses on wave length of λ1,06 microns depending on dozes of γ-irradiation and intensity of laser radiation are made. Doze dependences of charge and power spectra and quantitative characteristics of ions of plasma of breakdown were investigated at q≥ q s . In the investigated interval of dozes of γ- irradiation and intensity of laser radiation by a method of optical microscopy the morphology of occurring laser damage as surfaces, and volume of glass is also studied. It is found, that γ -induced defects in investigated glasses strongly effect on thresholds of damage q s and q d and on characteristics of ions

  17. Dielectric nanoresonators for light manipulation

    Science.gov (United States)

    Yang, Zhong-Jian; Jiang, Ruibin; Zhuo, Xiaolu; Xie, Ya-Ming; Wang, Jianfang; Lin, Hai-Qing

    2017-07-01

    Nanostructures made of dielectric materials with high or moderate refractive indexes can support strong electric and magnetic resonances in the optical region. They can therefore function as nanoresonators. In addition to plasmonic metal nanostructures that have been widely investigated, dielectric nanoresonators provide a new type of building blocks for realizing powerful and versatile nanoscale light manipulation. In contrast to plasmonic metal nanostructures, nanoresonators made of appropriate dielectric materials are low-cost, earth-abundant and have very small or even negligible light energy losses. As a result, they will find potential applications in a number of photonic devices, especially those that require low energy losses. In this review, we describe the recent progress on the experimental and theoretical studies of dielectric nanoresonators. We start from the basic theory of the electromagnetic responses of dielectric nanoresonators and their fabrication methods. The optical properties of individual dielectric nanoresonators are then elaborated, followed by the coupling behaviors between dielectric nanoresonators, between dielectric nanoresonators and substrates, and between dielectric nanoresonators and plasmonic metal nanostructures. The applications of dielectric nanoresonators are further described. Finally, the challenges and opportunities in this field are discussed.

  18. Optical constants, dispersion energy parameters and dielectric properties of ultra-smooth nanocrystalline BiVO4 thin films prepared by rf-magnetron sputtering

    Science.gov (United States)

    Sarkar, S.; Das, N. S.; Chattopadhyay, K. K.

    2014-07-01

    BiVO4 thin films have been prepared through radio frequency (rf) magnetron sputtering of a pre-fabricated BiVO4 target on ITO coated glass (ITO-glass) substrate and bare glass substrates. BiVO4 target material was prepared through solid-state reaction method by heating Bi2O3 and V2O5 mixture at 800 °C for 8 h. The films were characterized by X-ray diffraction, UV-Vis spectroscopy, LCR meter, field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy. BiVO4 thin films deposited on the ITO-glass substrate are much smoother compared to the thin films prepared on bare glass substrate. The rms surface roughness calculated from the AFM images comes out to be 0.74 nm and 4.2 nm for the films deposited on the ITO-glass substrate and bare glass substrate for the deposition time 150 min respectively. Optical constants and energy dispersion parameters of these extra-smooth BiVO4 thin films have been investigated in detail. Dielectric properties of the BiVO4 thin films on ITO-glass substrate were also investigated. The frequency dependence of dielectric constant of the BiVO4 thin films has been measured in the frequency range from 20 Hz to 2 MHz. It was found that the dielectric constant increased from 145 to 343 at 20 Hz as the film thickness increased from 90 nm to 145 nm (deposition time increased from 60 min to 150 min). It shows higher dielectric constant compared to the literature value of BiVO4.

  19. Synthesis, optical properties and photostability of novel fluorinated organic–inorganic hybrid (R–NH3)2PbX4 semiconductors

    International Nuclear Information System (INIS)

    Wei, Y; Lauret, J-S; Deleporte, E; Audebert, P; Galmiche, L

    2013-01-01

    We report on the synthesis and the optical properties of several novel semiconductors (R–NH 3 ) 2 PbX 4 (X = Br − , I − or Cl − ). These semiconductors are two-dimensional organic–inorganic perovskite (2DOIP) materials and have multiple quantum-well energy level structures. We vary the organic components (R-NH 3 + ), introducing fluorine atoms into the organic part, on the phenyl ring of the amine. We discuss its influence on the self-organization ability and long-term photostability of the 2DOIPs. The trends of introducing fluorine atoms on the self-organization and long-term photostability of 2DOIPs are obtained by analysing the optical experimental results, and show that the influence of the fluorine position on the benzene ring is quite important. The most promising compounds seem to be the ones with the fluorine atom sitting on the para position of the phenyl group. (paper)

  20. Dielectric function and electro-optical properties of (Al,Ga)N/GaN-heterostructures; Dielektrische Funktion und elektrooptische Eigenschaften von (Al,Ga)N/GaN-Heterostrukturen

    Energy Technology Data Exchange (ETDEWEB)

    Buchheim, Carsten

    2010-04-23

    In this work extensive investigations on nitride semiconductors by optical spectroscopy are presented. The ordinary and the extraordinary component of the dielectric function of GaN in the spectral range from 1.2 to 9.8 eV is shown for the first time. It is demonstrated, that the transparent spectral range is clearly influenced by higher energetic critical points of the band structure. The optical selection rules for GaN and AlN are verified considering the actual strain state. The change of the valence band ordering of AlN in comparison to GaN is proven and the crystal field splitting is estimated for AlN. The ordinary dielectric function of AlGaN is determined for different Al contents. The data are used for developing an analytical model, which includes excitonic effects and bowings. It allows the calculation of the dielectric function for arbitrary alloy compositions. (GaN/)AlGaN/GaN heterostructures are investigated by spectroscopic ellipsometry as well as by photoreflectance and electroreflectance. The optical data yields the electric field strengths of the individual layers to determine the density of the two-dimensional carrier gases at the heterointerfaces with high accuracy. The surface potential is calculated from the combination of experiments and Schroedinger-Poisson calculations. Its dependency on the Al content is quantified. For the special case of thick cap layers the coexistence of electron and hole gases in one sample is experimentally proven for the first time. Several interband transitions between quantized states in AlN/GaN superlattices are observed by electroreflectance. The comparison to quantum mechanical calculations demonstrates the influence of strain and electrical fields (quantum confined Stark effect). For both the ratio of the thicknesses of quantum wells and barriers is crucial. From the dielectric function of the superlattices it becomes obvious, that quantum size effects are not only important for the vicinity of the bandgap, but

  1. Optical anisotropy of layered metal-dielectric nanostructures based on dense 2D-arrays of silver nanoparticles

    International Nuclear Information System (INIS)

    Jeshchenko, O.A.

    2013-01-01

    The spatial and polarization anisotropy of extinction spectra of parallel dense 2D-monolayers of Ag nanoparticles separated by dielectric films is theoretically studied. The dependences are interpreted as a result of collectivization of surface plasmon modes occurring due to strong dipole-dipole coupling silver nanoparticles

  2. Dielectric properties of binary solutions a data handbook

    CERN Document Server

    Akhadov, Y Y

    1980-01-01

    Dielectric Properties of Binary Solutions focuses on the investigation of the dielectric properties of solutions, as well as the molecular interactions and mechanisms of molecular processes that occur in liquids. The book first discusses the fundamental formulas describing the dielectric properties of liquids and dielectric data for binary systems of non-aqueous solutions. Topics include permittivity and dielectric dispersion parameters of non-aqueous solutions of organic and inorganic compounds. The text also tackles dielectric data for binary systems of aqueous solutions, including permittiv

  3. Laser amplification in excited dielectrics

    DEFF Research Database (Denmark)

    Winkler, Thomas; Haahr-Lillevang, Lasse; Sarpe, Cristian

    2018-01-01

    Wide-bandgap dielectrics such as glasses or water are transparent at visible and infrared wavelengths. This changes when they are exposed to ultrashort and highly intense laser pulses. Different interaction mechanisms lead to the appearance of various transient nonlinear optical phenomena. Using...... these, the optical properties of dielectrics can be controlled from the transparent to the metal-like state. Here we expand this range by a yet unexplored mechanism in excited dielectrics: amplification. In a two-colour pump-probe experiment, we show that a 400nm femtosecond laser pulse is coherently...

  4. Electronic structure calculations and optical properties of a new organic-inorganic luminescent perovskite: (C9H19NH3)2PbI2Br2

    International Nuclear Information System (INIS)

    Abid, H.; Samet, A.; Dammak, T.; Mlayah, A.; Hlil, E.K.; Abid, Y.

    2011-01-01

    (C 9 H 19 NH 3 ) 2 PbI 2 Br 2 compound is a new crystal belonging to the large hybrid organic-inorganic perovskites compounds family. Optical properties are investigated by optical absorption UV-visible and photoluminescence (PL) techniques. Bands to band absorption peak at 2.44 eV as well as an extremely strong yellow-green photoluminescence emission at 2.17 eV is observed at room temperature. First principle calculations based on the DFT and FLAPW methods combined with LDA approximation are performed as well. Density of state close to the gap is presented and discussed in terms of optical absorption and photoluminescence experimental results. The perfect agreement between experimental data and electronic structure calculations is highlighted. - Highlights: → (C 9 H 19 NH 3 ) 2 PbI 2 Br 2 compound is a new crystal with strong yellow-green PL emission at 2.17 eV. → Calculations based on DFT and FLAPW method combined with LDA approximation are performed. → Gap, optical transitions and exciton presence were predicted from density of states. → Agreement between experimental data and electronic structure calculations.

  5. Crystal growth, structural, spectral, thermal, dielectric, linear and nonlinear optical characteristics of a new organic acentric material: L-Methionine-Succinic acid (2/1)

    Science.gov (United States)

    Nageshwari, M.; Kumari, C. Rathika Thaya; Vinitha, G.; Mohamed, M. Peer; Sudha, S.; Caroline, M. Lydia

    2018-03-01

    L-Methionine-Succinic acid (2/1) (LMSA), 2C5H11NO2S·C4H6O4, a novel nonlinear optical material which belongs to the class of organic category was grown-up for the first time by the technique of slow evaporation. Purity of LMSA was improved using repetitive recrystallization. LMSA was analyzed by single crystal and powder X-ray diffraction investigation to affirm the crystal structure and crystalline character. The single crystal XRD revealed that LMSA corresponds to the crystal system of triclinic with P1 as space group showing the asymmetric unit consists of a neutral succinic acid molecule and two methionine residues which are crystallographically independent existing in zwitterionic form. The functional groups existing in LMSA was accomplished using Fourier transform infrared spectroscopy. The optical transparency and the band gap energy were identified utilizing UV-Visible spectrum. The optical constants specifically reflectance and extinction coefficient clearly indicate the elevated transparency of LMSA. The thermal analyses affirmed its thermal stability. The luminescence behavior of LMSA has been analyzed by Photoluminescence (PL) spectral study. The mechanical, laser damage threshold and dielectric investigation of LMSA was done to suggest the material for practical applications. The second and third harmonic generation efficacy was confirmed by means of Kurtz-Perry and Z-scan procedure which attest its potentiality in the domain of nonlinear optics.

  6. Structural, optical and dielectric properties of Sn0.97Ce0.03O2 nanostructures

    Science.gov (United States)

    Ahmed, Ateeq; Siddique, M. Naseem; Ali, Tinku; Tripathi, P.

    2018-05-01

    In present work, 3% cerium doped SnO2 (Sn0.97Ce0.03O2) nanoparticles (NPs) have been synthesized by sol-gel method. The prepared sample has been characterized by using various techniques such as XRD, UV-visible absorption spectroscopy and LCR meter measurements. Structural Rietveld refinement of XRD data reveals that (Sn0.97Ce0.03O2) sample has a pure single phase tetragonal structure with space group (P42/mnm) without creating any impurity phase such as cerium oxide. UV-visible spectroscopy determines band gap value 3.47 eV for (Sn0.97Ce0.03O2) NPs using Tauc's relation. Dielectric constant and loss decreased with increase in frequency while ac conductivity was found to increase with increase in frequency. The observed dielectric results has been explained in the light of Maxwell-Wagner model.

  7. Design methodology for all-optical bistable switches based on a plasmonic resonator sandwiched between dielectric waveguides

    International Nuclear Information System (INIS)

    Xiang, Yinxiao; Cai, Wei; Wang, Lei; Ying, Cuifeng; Zhang, Xinzheng; Xu, Jingjun

    2014-01-01

    We present a bistable device consisting of a Bragg grating resonator with a Kerr medium sandwiched between two dielectric slab waveguides. The resonator is situated in a nanometer-scaled metal–insulator–metal plasmonic waveguide. Due to the dimensional confinement from the dielectric waveguide to the nanoscaled plasmonic waveguide, electric fields are enhanced greatly, which will further reduce the threshold value. Moreover, a semi-analytic method, based on the impedance theory and the transfer matrix method, is developed to study the transmission and reflection spectra as well as the bistability loop of such a switch. Our method is fast and accurate, as confirmed by the finite-difference time-domain simulation. (invited paper)

  8. Development of nonlinear optical materials using inorganic-organic complexes; Hisenkei kogaku zairyo to shite no yuki-muki fukugotai no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, N. [Hokkaido University, Sapporo (Japan). Catalysis Research Center

    1994-12-15

    Development was attempted on organic-inorganic complexes as nonlinear optical materials. The objective is to develop elements with SHG activity (generating second harmonics) to change a visible ray into an ultraviolet ray by inserting P-nitroaniline (pNA) into such solid acids having strong static electric field as zeolite, laminar compounds, and heteropolyacid, and utilizing the static electric field and the molecule coordination field of inorganic compounds. Used for the pNA{center_dot}Bronsted acid composite are HBr, HCl, HNO3, and H2SO4. The pNA that has a center of symmetry in the crystalline structure and does not generate the second harmonics shows SHG when it is formed into a composite with HBr. No SHG is recognized in other acid composites. This difference is due to the difference in the crystalline structure. The SHG activity was generated when pNA is loaded onto alumina and silica as solid oxides. When zeolites are used as carriers, no SHG was observed. A composite of pNA{center_dot}AlCl3 has high SHG intensity, which reached a maximum when the pNA/AlCl3 ratio was two. This composite showed four new peaks that belong to the SHG activity phase. 8 refs., 2 figs., 2 tabs.

  9. Structural, Optical, and Dielectric Investigations of the Relaxor PLZT 9,75/65/35 Ceramics Irradiated by High-Current Pulsed Electron Beam

    CERN Document Server

    Efimov, V V; Kalmikov, A V; Klevtsova, E A; Minashkin, V F; Novikova, N N; Sikolenko, V V; Skripnik, A V; Sternberg, A; Tiutiunnikov, S I; Yakovlev, V A

    2002-01-01

    First time comprehensive study of high-current pulsed electron irradiation effects on the structural, optical and dielectric properties of relaxor (Pb_{(1-x)}La^{x}(Zr_{0.65}Ti_{0.35})_{1-x/4}O_{3} ceramics with x=9.75% has been provided. The electron beam had the following parameters: energy E_{e}=250 keV, current density J_{e}=1000 A/cm^{2}, pulse duration tau = 300 ns, density 10^{15} electrons/cm^{2} per pulse. Infrared reflectivity spectra in the region of 100-2000 cm^{-1} were obtained in virgin, irradiated by 1500 pulses and annealed up to t=500^{circ}C ceramics. The reconstruction of perovskite ABO_{3} structure in irradiated samples has been studied by complex use of X-ray and neutron scattering and IR spectroscopy techniques revealing the changes in transverse and longitudinal phonon modes, oscillators strength and damping of modes. Radiation effects on temperature behaviour of dielectric permittivity in the region of phase transition were studied. The possible mechanisms of pulsed electron irradiat...

  10. Synthesis, vibrational and optical properties of a new three-layered organic-inorganic perovskite (C4H9NH3)4Pb3I4Br6

    International Nuclear Information System (INIS)

    Dammak, T.; Elleuch, S.; Bougzhala, H.; Mlayah, A.; Chtourou, R.; Abid, Y.

    2009-01-01

    An organic-inorganic hybrid perovskite (C 4 H 9 NH 3 ) 4 Pb 3 I 4 Br 6 was synthesized and studied by X-ray diffraction, Raman and infrared spectroscopies, optical transmission and photoluminescence. The title compound, abbreviated (C 4 ) 4 Pb 3 I 4 Br 6 , crystallises in a periodic two-dimensional multilayer structure with P2 1 /a space group. The structure is built up from alternating inorganic and organic layers. Each inorganic layer consists of three sheets of PbX 6 (X=I, Br) octahedra. Raman and infrared spectra of the title compound were recorded in the 100-3500 and 400-4000 cm -1 frequency ranges, respectively. An assignment of the observed vibration modes is reported. Optical transmission measurements, performed on thin films of (C 4 ) 4 Pb 3 I 4 Br 6 , revealed two absorption bands at 474 and 508 nm. Photoluminescence measurements have shown a green emission peak at 519 nm.

  11. Effect of Gd{sup 3+} substitution on structural, magnetic, dielectric and optical properties of nanocrystalline CoFe{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Seema [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, Noida 201307 (India); Kumar, Manoj, E-mail: mkumar.phy@gmail.com [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, Noida 201307 (India); Chhoker, Sandeep [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, Noida 201307 (India); Kumar, Arun; Singh, Mahavir [Department of Physics, Himachal Pradesh University, Shimla 5 (India)

    2017-03-15

    Nanoparticles of CoGd{sub x}Fe{sub 2−x}O{sub 4} with x=0.0, 0.03, 0.05, 0.07, 0.10 and 0.15 were synthesized by co-precipitation method. Gd{sup 3+} substitution effect on different properties of nanocrystalline CoFe{sub 2}O{sub 4} has been studied. X-ray diffraction and Raman spectroscopy confirmed the formation of single phase cubic mixed spinel structure. Cation distribution has been proposed from Rietveld refined data. Mössbauer spectra at room temperature showed two ferrimagnetic Zeeman sextets with one superparamagnetic doublet. Mössbauer parameters suggested that Gd{sup 3+} ions occupy the octahedral site in CoFe{sub 2}O{sub 4}. Room temperature magnetic measurements exhibited that the saturation magnetization decreased from 91 emu/gm to 54 emu/gm for x=0.0 to 0.15 samples. The coercivity decreased from 1120 Oe to 340 Oe for x=0.0 to 0.07 samples and increased from 400 Oe to 590 Oe for x=0.10 and 0.15 samples, respectively. Raman analysis showed that the degree of inversion with Gd{sup 3+} substitution supporting the variation of coercivity. Electron spin resonance spectra revealed the dominancy of superexchange interactions in these samples. Optical band gap measurement suggested that all samples are indirect band gap materials and band gap has been decreased with Gd{sup 3+} substitution. Both dielectric constant and dielectric loss is found to decrease because of the decrease in hopping rate with the Gd{sup 3+} substitution for Fe{sup 3+} at the octahedral sites. Low dielectric loss suggested the applicability of Gd{sup 3+} doped CoFe{sub 2}O{sub 4} nanoparticles for high frequency microwave device applications. - Highlights: • Gd{sup 3+} ions were successfully added in to the spinel lattice of CoFe{sub 2}O{sub 4}. • Magnetic hysteresis loss is influenced by Gd{sup 3+} doping. • All doped samples exhibit normal dielectric dispersion behaviour of spinel ferrites. • UV–vis diffuse spectroscopy concludes band gap is reduced by Gd{sup 3+} doping.

  12. Optical and Dielectric Properties of CuAl2O4 Films Synthesized by Solid-Phase Epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Leu, L. C. [University of Florida, Gainesville; Norton, David P. [University of Florida; Jellison Jr, Gerald Earle [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Xiong, X. [SuperPower Incorporated, Schenectady, New York

    2007-01-01

    The synthesis and properties of CuAl{sub 2}O{sub 4} thin films have been examined. The CuAl{sub 2}O{sub 4} films were deposited via reactive direct current magnetron sputter using a CuAl{sub 2} target. As-deposited films were amorphous. Post-deposition annealing at high temperature in oxygen yielded solid-phase epitaxy on MgO. The film orientation was cube-on-cube epitaxy on (001) MgO single-crystal substrates. The films were transparent to visible light. The band gap of crystalline CuAl{sub 2}O{sub 4} was determined to be {approx} 4 eV using a Tauc plot from the optical transmission spectrum. The dielectric constant of the amorphous films was determined to be {approx} 20-23 at 1-100 kHz.

  13. Boron nitride as two dimensional dielectric: Reliability and dielectric breakdown

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yanfeng; Pan, Chengbin; Hui, Fei; Shi, Yuanyuan; Lanza, Mario, E-mail: mlanza@suda.edu.cn [Institute of Functional Nano and Soft Materials, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren-Ai Road, Suzhou 215123 (China); Zhang, Meiyun; Long, Shibing [Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China); Lian, Xiaojuan; Miao, Feng [National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Larcher, Luca [DISMI, Università di Modena e Reggio Emilia, 42122 Reggio Emilia (Italy); Wu, Ernest [IBM Research Division, Essex Junction, Vermont 05452 (United States)

    2016-01-04

    Boron Nitride (BN) is a two dimensional insulator with excellent chemical, thermal, mechanical, and optical properties, which make it especially attractive for logic device applications. Nevertheless, its insulating properties and reliability as a dielectric material have never been analyzed in-depth. Here, we present the first thorough characterization of BN as dielectric film using nanoscale and device level experiments complementing with theoretical study. Our results reveal that BN is extremely stable against voltage stress, and it does not show the reliability problems related to conventional dielectrics like HfO{sub 2}, such as charge trapping and detrapping, stress induced leakage current, and untimely dielectric breakdown. Moreover, we observe a unique layer-by-layer dielectric breakdown, both at the nanoscale and device level. These findings may be of interest for many materials scientists and could open a new pathway towards two dimensional logic device applications.

  14. Morphological and Optical Characteristics of Chitosan(1-x):Cuox (4 ≤ x ≤ 12) Based Polymer Nano-Composites: Optical Dielectric Loss as an Alternative Method for Tauc's Model.

    Science.gov (United States)

    Aziz, Shujahadeen B

    2017-12-13

    In this work, copper (Cu) nanoparticles with observable surface plasmonic resonance (SPR) peaks were synthesized by an in-situ method. Chitosan host polymer was used as a reduction medium and a capping agent for the Cu nanoparticles. The surface morphology of the samples was investigated through the use of scanning electron micrograph (SEM) technique. Copper nanoparticles appeared as chains and white specks in the SEM images. The strong peaks due to the Cu element observed in the spectrum of energy dispersive analysis of X-rays. For the nanocomposite samples, obvious peaks due to the SPR phenomena were obtained in the Ultraviolet-visible (UV-vis) spectra. The effect of Cu nanoparticles on the host band gap was understood from absorption edges shifting of absorption edges to lower photon energy. The optical dielectric loss parameter obtained from the measurable quantities was used as an alternative method to study the band structure of the samples. Quantum mechanical models drawbacks, in the study of band gap, were explained based on the optical dielectric loss. A clear dispersion region was able to be observed in refractive indices spectra of the composite samples. A linear relationship with a regression value of 0.99 was achieved between the refractive index and volume fractions of CuI content. Cu nanoparticles with various sizes and homogenous dispersions were also determined from transmission electron microscope (TEM) images.

  15. Synthesis, growth, structural, optical, thermal, dielectric and mechanical studies of an organic guanidinium p-nitrophenolate crystal

    Science.gov (United States)

    Dhavamurthy, M.; Peramaiyan, G.; Mohan, R.

    2014-08-01

    Guanidinium p-nitrophenolate (GUNP), a novel organic compound, was synthesized and crystals were grown from methanol solution by a slow evaporation solution growth technique. A single crystal X-ray diffraction study elucidated the crystal structure of GUNP belonging to the orthorhombic crystal system with space group Pnma. Thermal studies revealed that the GUNP crystal is thermally stable up to 192 °C. The lower cut-off wavelength of GUNP was found to be 505 nm by UV-vis-NIR spectral studies. The luminescence properties of the GUNP crystal were investigated. The three independent tensor coefficients ε11, ε22 and ε33 of the dielectric permittivity were calculated. The mechanical properties of the grown crystal were studied by Vickers' microhardness hardness technique.

  16. Electric-field induced surface instabilities of soft dielectrics and their effects on optical transmittance and scattering

    Science.gov (United States)

    Shian, Samuel; Kjeer, Peter; Clarke, David R.

    2018-03-01

    When a voltage is applied to a percolative, mechanically compliant mat of carbon nanotubes (CNTs) on a smooth elastomer bilayer attached to an ITO coated glass substrate, the in-line optical transmittance decreases with increasing voltage. Two regimes of behavior have been identified based on optical scattering, bright field optical microscopy, and confocal optical microscopy. In the low field regime, the electric field produces a spatially inhomogeneous surface deformation of the elastomer that causes local variations in optical refraction and modulates the light transmittance. The spatial variation is associated with the distribution of the CNTs over the surface. At higher fields, above a threshold voltage, an array of pits in the surface form by a nucleation and growth mechanism and these also scatter light. The formation of pits, and creases, in the thickness of the elastomer, is due to a previously identified electro-mechanical surface instability. When the applied voltage is decreased from its maximum, the transmittance returns to its original value although there is a transmittance hysteresis and a complicated time response. When the applied voltage exceeds the threshold voltage, there can be remnant optical contrast associated with creasing of the elastomer and the recovery time appears to be dependent on local jamming of CNTs in areas where the pits formed. A potential application of this work as an electrically tunable privacy window or camouflaging devices is demonstrated.

  17. Transfiguring structural, optical and dielectric properties of cadmium thiourea acetate crystal by the addition of L-threonine for laser assisted device applications

    Science.gov (United States)

    Kulkarni, Rupali B.; Anis, Mohd; Hussaini, S. S.; Shirsat, Mahendra D.

    2018-03-01

    Present investigation reports the growth of pure and L-threonine (LT) doped cadmium thiourea acetate (CTA) crystals by slow solution evaporation technique followed by structural, optical and dielectric characterization studies. A bulk single crystal of LT-CTA has been grown at temperature 38 °C. The single crystal x-ray diffraction technique has been employed to confirm the structural parameters of pure and LT doped CTA crystals. The increase in optical transparency of LT-CTA crystal was ascertained in the range of 200 to 900 nm using UV-visible spectral analysis. The widened optical band gap of the LT-CTA crystal is found to be 4.7 eV. Pure and doped crystals are subjected to FT-IR analysis to indicate the presence of functional groups quantitatively. Appreciable enhancement in second harmonic generation (SHG) efficiency of LT-CTA crystal with reference to parent CTA was confirmed from Kurtz-Perry SHG test (1.31 times of CTA crystal). The assertive influence of LT on electrical properties of grown crystals has been investigated in the temperature range 35 °C-120 °C. Electronic purity and the color centered photoluminescence emission nature of pure and IA-CTA crystals were justified by luminescence analysis. With the aid of single beam Z-scan analysis, the Kerr lensing nonlinearity was identified and the magnitude of TONLO parameters has been determined. The cubic susceptibility (χ3) and figure of merit (FOM) was found to be 4.81 × 10-4esu and 978.35. Results vitalize LT-CTA for laser stabilization systems.

  18. Bulk monocrystal growth, optical, dielectric, third order nonlinear, thermal and mechanical studies on HCl added L-alanine: An organic NLO material

    Energy Technology Data Exchange (ETDEWEB)

    Shkir, Mohd, E-mail: shkirphysics@gmail.com [Advanced Functional Materials & Optoelectronic Laboratory (AFMOL), Physics Department, Faculty of Science, King Khalid University, Abha (Saudi Arabia); Yahia, I.S., E-mail: dr_isyahia@yahoo.com [Advanced Functional Materials & Optoelectronic Laboratory (AFMOL), Physics Department, Faculty of Science, King Khalid University, Abha (Saudi Arabia); Nano-Science & Semiconductor Labs, Physics Department, Faculty of Education, Ain Shams University, Roxy, Cairo (Egypt); Al-Qahtani, A.M.A. [Advanced Functional Materials & Optoelectronic Laboratory (AFMOL), Physics Department, Faculty of Science, King Khalid University, Abha (Saudi Arabia)

    2016-12-01

    In the current work, good quality bulk size (∼32 mm × 23 mm × 10 mm) single crystals of HCl added L-alanine with well-defined morphology are successfully grown using slow evaporation technique. Crystal structure and other structural parameters were evaluated from X-ray diffraction data. Vibrational assessment of the grown crystal was done by FT-Raman analysis. The presence of chlorine and good quality of the grown crystal was confirmed by SEM/EDX analysis. Solid state UV–Vis–NIR diffused reflectance was measured and direct and indirect optical band gap was calculated using Kubelka-Munk relation and found to be 5.64 and 5 eV respectively. Dielectric measurement was carried out in high frequency range. Third order nonlinear optical susceptibility value was found to be enhanced from 1.91 × 10{sup −6} (pure) to 8.6 × 10{sup −6} esu (LAHCl). Good thermal stability of grown crystals was confirmed from DSC analysis. The enhancement in mechanical strength and crystalline perfection was also observed. - Highlights: • Bulk size (32 mm × 23 mm × 10 mm), good crystalline perfection HCl added L-alanine monocrystal is grown. • The shift in X-ray diffraction and vibrational peaks confirms the interaction of HCl. • The high optical transparency and band gap confirms its application in optoelectronic devices. • Third order NLO properties are found to be enhanced in HCl added L-alanine crystals. • The mechanical strength of the grown crystals is found to be enhanced due HCl addition.

  19. An optical and dielectric spectroscopy study of Er.sup.3+./sup.-doped KTaO.sub.3./sub..

    Czech Academy of Sciences Publication Activity Database

    Trepakov, Vladimír; Skvortsov, A.; Poletaev, N.; Potůček, Zdeněk; Nuzhnyy, Dmitry; Jastrabík, Lubomír; Dejneka, Alexandr

    2011-01-01

    Roč. 248, č. 12 (2011), s. 2908-2915 ISSN 0370-1972 R&D Projects: GA ČR GC202/09/J017; GA AV ČR KAN301370701; GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100522 Keywords : Er 3+ centres * IR spectroscopy * optical absorption photoluminescence * potassium tantalate * THz spectroscopy Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.316, year: 2011

  20. Actuated polymer based dielectric mirror for visual spectral range applications

    Science.gov (United States)

    Vergara, Pedro P.; Lunardi, Leda

    2017-08-01

    Miniature dielectric mirrors are useful components for lasers, thin film beam splitters and high quality mirrors in optics. These mirrors usually made from rigid inorganic materials can achieve a reflectance of almost one hundred percent. Being structural components, as soon as fabricated their reflectance and/or bandwidth remains constant. Here it is presented a novel fabrication process of a dielectric mirror based on free standing polymer layers. By applying an electrostatic force between the top and the bottom layers the reflectance can be changed. The large difference between the polymers refractive index and the air allows to achieve a reflectance of more than 85% using only six pairs of nanolayers. Preliminary simulations indicate an actuation speed of less than 1ms. Experimental optical characterization of fabricated structures agrees well with simulation results. Furthermore, structures can be designed to reflect a particular set of colors and/or isolated by using color filters, so a color pixel is fabricated, where the reflectance for each isolated color can be voltage controlled. Potential applications include an active component in a reflective screen display.

  1. Optically sensitive devices based on Pt nano particles fabricated by atomic layer deposition and embedded in a dielectric stack

    Energy Technology Data Exchange (ETDEWEB)

    Mikhelashvili, V.; Padmanabhan, R.; Eisenstein, G. [Electrical Engineering Department, Technion, Haifa 3200 (Israel); Russell Berrie Nanotechnology Institute, Technion, Haifa 3200 (Israel); Meyler, B.; Yofis, S.; Weindling, S.; Salzman, J. [Electrical Engineering Department, Technion, Haifa 3200 (Israel); Atiya, G.; Cohen-Hyams, Z.; Kaplan, W. D. [Department of Material Science and Engineering, Technion, Haifa 3200 (Israel); Russell Berrie Nanotechnology Institute, Technion, Haifa 3200 (Israel); Ankonina, G. [Russell Berrie Nanotechnology Institute, Technion, Haifa 3200 (Israel); Photovoltaic Laboratory, Technion, Haifa 3200 (Israel)

    2015-10-07

    We report a series of metal insulator semiconductor devices with embedded Pt nano particles (NPs) fabricated using a low temperature atomic layer deposition process. Optically sensitive nonvolatile memory cells as well as optical sensors: (i) varactors, whose capacitance-voltage characteristics, nonlinearity, and peak capacitance are strongly dependent on illumination intensity; (ii) highly linear photo detectors whose responsivity is enhanced due to the Pt NPs. Both single devices and back to back pairs of diodes were used. The different configurations enable a variety of functionalities with many potential applications in biomedical sensing, environmental surveying, simple imagers for consumer electronics and military uses. The simplicity and planar configuration of the proposed devices makes them suitable for standard CMOS fabrication technology.

  2. Optically sensitive devices based on Pt nano particles fabricated by atomic layer deposition and embedded in a dielectric stack

    International Nuclear Information System (INIS)

    Mikhelashvili, V.; Padmanabhan, R.; Eisenstein, G.; Meyler, B.; Yofis, S.; Weindling, S.; Salzman, J.; Atiya, G.; Cohen-Hyams, Z.; Kaplan, W. D.; Ankonina, G.

    2015-01-01

    We report a series of metal insulator semiconductor devices with embedded Pt nano particles (NPs) fabricated using a low temperature atomic layer deposition process. Optically sensitive nonvolatile memory cells as well as optical sensors: (i) varactors, whose capacitance-voltage characteristics, nonlinearity, and peak capacitance are strongly dependent on illumination intensity; (ii) highly linear photo detectors whose responsivity is enhanced due to the Pt NPs. Both single devices and back to back pairs of diodes were used. The different configurations enable a variety of functionalities with many potential applications in biomedical sensing, environmental surveying, simple imagers for consumer electronics and military uses. The simplicity and planar configuration of the proposed devices makes them suitable for standard CMOS fabrication technology

  3. Control of optical properties of metal-dielectric planar plasmonic nanostructures by adjusting their architecture in the case of TiAlN/Ag system

    Science.gov (United States)

    Wainstein, D. L.; Vakhrushev, V. O.; Kovalev, A. I.

    2017-05-01

    The multilayer Ag/(Ti34Al66)N metal-insulator-metal (MIM) heterostructures with different thicknesses of individual layers varied from several to several hundred nanometers were fabricated by DC-magnetron sputtering on the surfaces of Si single crystal wafers. The coatings structure was determined by STEM. The phase composition and crystallography of individual layers were studied by X-ray diffraction. The reflection indexes were measured in the photons energies range from 1 to 5 eV, or from 1240 to 248 nm. The spectroscopy of plasmon losses and plasmon microscopy allowed us to measure the plasmons losses characteristic energies and their surface distribution. The energies of plasmons peaks and their locations are strongly depending on Ag layers thickness in the MIM nanocomposite. The surface plasmon with energy about 4 eV was observed in the middle of 20 nm Ag layer. The plasmons were localized at the metal/dielectric interface for Ag layers 5 nm and less. The reflectance spectral profiles edges positions at long and short waves are correlated with plasmons energies and features of their spatial distribution. The MIMs based on the TiAlN/Ag can find applications as optical filters, photovoltaic energy conversion devices, etc.

  4. Growth, spectral, thermal, laser damage threshold, microhardness, dielectric, linear and nonlinear optical properties of an organic single crystal: L-phenylalanine DL-mandelic acid

    Energy Technology Data Exchange (ETDEWEB)

    Jayaprakash, P. [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India); Peer Mohamed, M. [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India); Department of Physics, C. Abdul Hakeem College, Melvisharam 632 509, Tamil Nadu (India); Krishnan, P. [Department of Physics, St. Joseph’s College of Engineering, Chennai 600 119, Tamil Nadu (India); Nageshwari, M.; Mani, G. [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India); Lydia Caroline, M., E-mail: lydiacaroline2006@yahoo.co.in [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India)

    2016-12-15

    Single crystals of L-phenylalanine dl-mandelic acid [C{sub 9}H{sub 11}NO{sub 2}. C{sub 8}H{sub 8}O{sub 3}], have been grown by the slow evaporation technique at room temperature using aqueous solution. The single crystal XRD study confirms monoclinic system for the grown crystal. The functional groups present in the grown crystal have been identified by FTIR and FT-Raman analyses. The optical absorption studies show that the crystal is transparent in the visible region with a lower cut-off wavelength of 257 nm and the optical band gap energy E{sub g} is determined to be 4.62 eV. The Kurtz powder second harmonic generation was confirmed using Nd:YAG laser with fundamental wavelength of 1064 nm. Further, the thermal studies confirmed no weight loss up to 150°C for the as-grown crystal. The photoluminescence spectrum exhibited three peaks (414 nm, 519 nm, 568 nm) due to the donation of protons from carboxylic acid to amino group. Laser damage threshold value was found to be 4.98 GW/cm{sup 2}. The Vickers microhardness test was carried out on the grown crystals and there by Vickers hardness number (H{sub v}), work hardening coefficient (n), yield strength (σ{sub y}), stiffness constant C{sub 11} were evaluated. The dielectric behavior of the crystal has been determined in the frequency range 50 Hz–5 MHz at various temperatures.

  5. Enhanced optical confinement of dye-doped dielectric nanoparticles using a picosecond-pulsed near-infrared laser

    International Nuclear Information System (INIS)

    Kittiravechote, A; Chiang, W-Y; Usman, A; Liau, I; Masuhara, H

    2014-01-01

    We demonstrate a novel strategy to increase the capability of confining numerous dye-doped polymeric nanobeads (diameter 100 nm) with laser trapping. Unlike most classical works of optical trapping that address mainly the stiffness of the optical trap, our work concerns an increase in the number of particles confined near the laser focus. We developed an imaging system of light scattering in which a condenser lamp was employed to illuminate the focal plane of the objective lens, and the scattering of the incoherent light was specifically measured to determine the number of confined nanobeads. In contrast to preceding work that used mainly continuous-wave or femtosecond-pulsed lasers, we employed a picosecond-pulsed laser with the half-wavelength of the laser particularly falling within the absorption band of the dopant. Our results show that the number of doped nanobeads held by the laser is significantly greater than that of the bare nanobeads of the same dimension. In striking contrast, the confinement of the nanobeads of the two types was comparable when a continuous-wave laser of the same wavelength and power was employed. The number of confined dye-doped nanobeads increased nonlinearly with the power of the pulsed laser; this dependence was fitted satisfactorily with a second-order polynomial. Supported by theoretical analysis, we attribute the enhanced confinement of doped nanobeads in part to an increased effective refractive index resulting from two-photon resonance between the optical field of the laser and the dopant of the nanobead. We envisage that our findings would evoke applications that benefit from controlled confinement or aggregation of nanomaterials with the employment of near-infrared pulsed lasers. (letter)

  6. Quenching Mo optical losses in CIGS solar cells by a point contacted dual-layer dielectric spacer: a 3-D optical study

    NARCIS (Netherlands)

    Rezaei, N.; Isabella, O.; Vroon, Z.; Zeman, M.

    2018-01-01

    A 3-D optical modelling was calibrated to calculate the light absorption and the total reflection of fabricated CIGS solar cells. Absorption losses at molybdenum (Mo) / CIGS interface were explained in terms of plasmonic waves. To quench these losses, we assumed the insertion of a lossless

  7. Quenching Mo optical losses in CIGS solar cells by a point contacted dual-layer dielectric spacer : A 3-D optical study

    NARCIS (Netherlands)

    Rezaei, N.; Isabella, O.; Vroon, Zeger; Zeman, M.

    2018-01-01

    A 3-D optical modelling was calibrated to calculate the light absorption and the total reflection of fabricated CIGS solar cells. Absorption losses at molybdenum (Mo) / CIGS interface were explained in terms of plasmonic waves. To quench these losses, we assumed the insertion of a lossless

  8. Electromagnetic properties of metal-dielectric media and their applications

    Science.gov (United States)

    Animilli, Shravan Rakesh

    composites. Based on the obtained numerical data a scaling theory for the higher order electric field moments is developed. A distinct evidence of singularities in the surface plasmon density of states and localization length is obtained, correlating with results previously obtained for two dimensional systems. This leads to the main finding of this work; i.e., the delocalization of surface plasmon states in percolating metal-dielectric composite materials is universally present regardless of the dimensionality of the problem. This dissertation also proposes a new approach toward developing highly efficient inorganic/organic solar cell, by presenting a method for enhancement in the optical absorption and overall cell efficiency. Specifically, the approach improves the operation characteristics of inorganic semiconductor (e.g. Si and a-Si) and organic (P3HT:PCBM) thin film solar cells by integrating a thin, inhomogeneous, metal-dielectric composite (MDC) electrode at the interface between the transparent electrode and active layer. Through numerical simulations, we show that under solar illumination, surface plasmons are excited within the fractal MDC electrode across an extremely broad range of optical frequencies, trapping the incoming light and ensuring an optimal absorption into the active layer of the solar cells. An analytical model is developed to study the I-V characteristics of the cells, providing a pathway toward achieving optimal efficiency and better understanding of the behavior of charge carriers. Using this model, it is shown that including gold MDC electrodes can lead to an enhancement in solar cell power conversion efficiency up to 33% higher compared to the benchmark device.

  9. Laser amplification in excited dielectrics

    Science.gov (United States)

    Winkler, Thomas; Haahr-Lillevang, Lasse; Sarpe, Cristian; Zielinski, Bastian; Götte, Nadine; Senftleben, Arne; Balling, Peter; Baumert, Thomas

    2018-01-01

    Wide-bandgap dielectrics such as glasses or water are transparent at visible and infrared wavelengths. This changes when they are exposed to ultrashort and highly intense laser pulses. Different interaction mechanisms lead to the appearance of various transient nonlinear optical phenomena. Using these, the optical properties of dielectrics can be controlled from the transparent to the metal-like state. Here we expand this range by a yet unexplored mechanism in excited dielectrics: amplification. In a two-colour pump-probe experiment, we show that a 400 nm femtosecond laser pulse is coherently amplified inside an excited sapphire sample on a scale of a few micrometres. Simulations strongly support the proposed two-photon stimulated emission process, which is temporally and spatially controllable. Consequently, we expect applications in all fields that demand strongly localized amplification.

  10. Enhancement of Faraday effect in one-dimensional magneto-optical photonic crystal including a magnetic layer with wavelength dependent off-diagonal elements of dielectric constant tensor

    International Nuclear Information System (INIS)

    Inui, Chie; Ozaki, Shinsuke; Kura, Hiroaki; Sato, Tetsuya

    2011-01-01

    Optical and magneto-optical properties of one-dimensional magneto-optical photonic crystal (1-D MPC) prepared by the sol-gel dip-coating method, including a magnetic defect layer composed of mixture of CoFe 2 O 4 and SiO 2 , are investigated from both the experimental and theoretical standpoints. The resonant transmission of light was observed around 570 nm in the photonic band gap. The Faraday rotation angle θ F showed two maxima at 490 and 640 nm, and the wavelength dependence of θ F above 760 nm was similar to that of the CoFe 2 O 4 +SiO 2 single-layer film. The two maxima of θ F are attributed to the enhanced Faraday rotation of nonmagnetic TiO 2 layers in the cavity structure and that in magnetic CoFe 2 O 4 +SiO 2 layer through the light localization in MPC. The maximum value of θ F due to the magnetic CoFe 2 O 4 +SiO 2 layer in the MPC was 22-times larger than that in the single-layer film. The simulation study of MPC with CoFe 2 O 4 +SiO 2 magnetic defect layer, based on the matrix approach method, showed that the resonant light transmission was accompanied by the localization of electric field, and large enhancement of θ F appeared at different wavelengths so as to agree with the experimental features. This can be explained in terms of the wavelength dependent off-diagonal components of the dielectric constant tensor in addition to the large extinction coefficient in the CoFe 2 O 4 +SiO 2 magnetic defect layer. - Highlights: → 1-D magnetic photonic crystal (MPC) prepared by sol-gel method. → Enhancement of Faraday rotation due to the magnetic defect layer of CoFe 2 O 4 . → Shift of wavelength of Faraday rotation maximum from resonant light transmission.

  11. Effect of nitrogen incorporation on the structural, optical and dielectric properties of reactive sputter grown ITO films

    Energy Technology Data Exchange (ETDEWEB)

    Gartner, M.; Stroescu, H. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Marin, A., E-mail: alexmarin@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Osiceanu, P. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Anastasescu, M., E-mail: manastasescu@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Stoica, M.; Nicolescu, M.; Duta, M.; Preda, S. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Aperathitis, E.; Pantazis, A.; Kampylafka, V. [FORTH-IESL, Crete (Greece); Modreanu, M. [Tyndall National Institute, University College Cork, Cork (Ireland); Zaharescu, M. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania)

    2014-09-15

    Highlights: • Graded optical model for ITON films is presented. • ITON thin films retain an amorphous structure even after RTA at 500 °C in N{sub 2} ambient. • The lowest resistivity was 2 × 10{sup −3} Ω cm for films deposited in 75%N{sub 2} and RTA at 500 °C. • Films deposited in 75% N{sub 2} and RTA at 500 °C have degenerate semiconductor behavior. • Chemical composition before and after RTA has been analyzed by XPS depth profiling. - Abstract: The changes in the optical, microstructural and electrical properties, following the nitrogen incorporation into indium tin oxide thin films are investigated. The films are formed by r.f. sputtering from an indium-tin-oxide (80% In{sub 2}O{sub 3}–20% SnO{sub 2}) target in a mixture of Ar and N{sub 2} plasma (75% N{sub 2}–25% Ar and 100% N{sub 2} respectively) on fused silica glass substrate. The impact of rapid thermal annealing (up to 500 °C, in N{sub 2} ambient) on the properties of indium tin oxynitride (ITON) thin films is also reported. The UV–vis–NIR ellipsometry (SE) characterization of ITON films was performed assuming several realistic approaches based on various oscillator models, using a chemical composition gradient depth profiling, in agreement with the X-ray photoelectron spectroscopy measurements. The Hall measurements show that the ITON films prepared by r.f. sputtering in 75% N{sub 2} and annealed at 500 °C behave as degenerate semiconductors. X-ray diffraction analysis proved that ITON thin films retain an amorphous structure even after RTA at 500 °C in N{sub 2} ambient and atomic force microscopy showed the formation of continuous and smooth ITON thin films, with a morphology consisting in quasispherical nanometric particles.

  12. Terahertz-frequency dielectric response of liquids

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd; Møller, Uffe; Cooke, David

    The dielectric response of liquids spans many decades in frequency. The dielectric response of a polar liquid is typically determined by relaxational dynamics of the dipolar moments of the liquid. In contrast, the dielectric response of a nonpolar liquid is determined by much weaker collision......-induced dipole moments. In the polar liquid water the fastest relaxational dynamics is found at terahertz frequencies, just below the first intermolecular vibrational and librational modes. In this presentation we will discuss optical terahertz spectroscopic techniques for measurement of the full dielectric...... function of liquids at terahertz frequencies. We will review the current understanding of the high-frequency dielectric spectrum of water, and discuss the relation between the dielectric spectrum and the thermodynamic properties of certain aqueous solutions....

  13. Linear and non-linear optics of nano-scale 2‧,7‧dichloro-fluorescein/FTO optical system: Bandgap and dielectric analysis

    Science.gov (United States)

    Iqbal, Javed; Yahia, I. S.; Zahran, H. Y.; AlFaify, S.; AlBassam, A. M.; El-Naggar, A. M.

    2016-12-01

    2‧,7‧ dichloro-Fluorescein (DCF) is a promising organic semiconductor material in different technological aspects such as solar cell, photodiode, Schottky diode. DCF thin film/conductive glass (FTO glass) was prepared by a low-cost spin coating technique. The spectrophotometric data such as the absorbance, reflectance and transmittance were cogitated in the 350-2500 nm wavelength range, at the normal incidence. The absorption (n) and linear refractive indices (k) were computed using the Fresnel's equations. The optical band gap was evaluated and it was found that there is two band gap described as follows: (1) It is related to the band gap of FTO/glass which is equal 3.4 eV and (2) the second one is related to the absorption edge of DCF equals 2.25 eV. The non-linear parameters such as the refractive index (n2) and optical susceptibility χ(3) were evaluated by the spectroscopic method based on the refractive index. Both (n2) and χ(3) increased rapidly on increasing the wavelength with redshift absorption. Our work represents a new idea about using FTO glass for a new generation of the optical device and technology.

  14. Dielectric waveguide amplifiers and lasers

    NARCIS (Netherlands)

    Pollnau, Markus

    The performance of semiconductor amplifiers and lasers has made them the preferred choice for optical gain on a micro-chip. In the past few years, we have demonstrated that also rare-earth-ion-doped dielectric waveguides show remarkable performance, ranging from a small-signal gain per unit length

  15. Infrared optical constants, dielectric constants, molar polarizabilities, transition moments, dipole moment derivatives and Raman spectrum of liquid cyclohexane

    Science.gov (United States)

    Keefe, C. Dale; Pickup, Janet E.

    2009-06-01

    Previous studies have been done in this laboratory focusing on the optical properties of several liquid aromatic and aliphatic hydrocarbons in the infrared. The current study reports the infrared and absorption Raman spectra of liquid cyclohexane. Infrared spectra were recorded at 25 °C over a wavenumber range of 7400-490 cm -1. Infrared measurements were taken using transmission cells with pathlengths ranging from 3 to 5000 μm. Raman spectra were recorded between 3700 and 100 cm -1 at 25 °C using a 180° reflection geometry. Ab initio calculations of the vibrational wavenumbers at the B3LYP/6311G level of theory were performed and used to help assign the observed IR and Raman spectra. Extensive assignments of the fundamentals and binary combinations observed in the infrared imaginary molar polarizability spectrum are reported. The imaginary molar polarizability spectrum was curve fitted to separate the intensity from the various transitions and used to determine the transition moments and magnitudes of the derivatives of the dipole moment with respect to the normal coordinates for the fundamentals.

  16. Microstructural, optical and dielectric properties of La{sub 0.8}Ba{sub 0.2}FeO{sub 3} nanostructures synthesized by sol-gel combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Ali, S. Asad, E-mail: asadsyyed@gmail.com; Naseem, Swaleha; Khan, Wasi; Naqvi, A. H. [Centre of Excellence in Materials Science (Nanomaterials), Department of Applied Physics, Z.H. College of Engg. & Technology, Aligarh Muslim University, Aligarh 202002 (India); Malik, Aisha [Department of Electrical Engineering, Aligarh Muslim University, Aligarh-202002 (India)

    2015-06-24

    Barium doped lanthanum ferrite (LaFeO{sub 3}) nanoparticles (NPs) were prepared by gel combustion method and calcinated at 700°C. Microstructural studies were carried by XRD and SEM techniques. The results of structural characterization show the formation of all samples in single phase without any impurity. Optical properties were studied by UV- visible technique. The energy band gap was calculated and obtained 3.01 eV. Dielectric properties characterized by LCR meter and have been observed appreciable changes. The observed behavior of the dielectric properties can be attributed on the basis of Koop’s theory based on Maxwell-Wagner two layer models in studied nanoparticles.

  17. Estimation of dark and active dielectric constants in the sub-THz frequency domain of an optically tunable organic semiconductor blend of poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester

    Science.gov (United States)

    Andy, Andre S.; Kneller, James W. E.; Sushko, Oleksandr; Dubrovka, Rostyslav; Parini, Clive; Scott, Ken; Kreouzis, Theo; Donnan, Robert S.

    2018-06-01

    The dielectric properties of a 95% poly(3-hexylthiophene):5% phenyl-C61-butyric acid methyl ester blend are measured in the dark and under white light illumination by quasi-optical transmissometry and terahertz time-domain spectroscopy. The real part of the dielectric constant varies monotonically between 2.75 and 3.50, in agreement with the literature, and displays a reversible photoinduced drop of 0.05–0.55 at sub-THz. The imaginary part fluctuates between 0.1 and 1.5 in the dark and displays a reversible increase upon illumination of 0.10–0.52 at sub-THz. The corresponding charge carrier concentration under illumination (using transient and steady-state photoconduction) is 1014 to 1015 cm‑3.

  18. Synthesis, characterization, and anomalous dielectric and conductivity performance of one-dimensional (bdaH)InSe2 (bda = 1,4-butanediamine)

    International Nuclear Information System (INIS)

    Du, Ke-Zhao; Hu, Wan-Biao; Hu, Bing; Guan, Xiang-Feng; Huang, Xiao-Ying

    2011-01-01

    Graphical abstract: Anomalous dielectric and conductivity performance have been observed in the organic-containing indium selenide (bdaH)InSe 2 , which are attributed to the water molecules existing in the crystal boundary rather than phase transition. Highlights: → The title compound is the first example of organic-containing one-dimensional indium selenide. → The anomalous dielectric peak is attributed to water molecules in crystal boundary. → The inorganic and organic components of the title compound are connected via hydrogen bonding to form a supramolecular three-dimensional network. -- Abstract: A new indium selenide, namely (bdaH)InSe 2 (1) (bda = 1,4-butanediamine) has been solvothermally synthesized and structurally characterized. It belongs to the non-centrosymmetric space group Fdd2. Its structure features an infinite one-dimensional anionic chain of [InSe 2 ] n n- with monoprotonated [bdaH] + as charge compensating cation. The organic [bdaH] + cations are joined into a supramolecular one-dimensional chain via N-H...N hydrogen bonding, which further interacts with the inorganic chain via N-H...Se and C-H...Se hydrogen bonding, forming a supramolecular three-dimensional network. Based on such a well-defined structure, the thermal stability, optical, conductivity, and dielectric properties were systematically investigated, showing that dielectric constant, as well as conductivity, had a hump at about 95 o C, which could be attributed to water molecules in the crystal boundary.

  19. Geometric phase from dielectric matrix

    International Nuclear Information System (INIS)

    Banerjee, D.

    2005-10-01

    The dielectric property of the anisotropic optical medium is found by considering the polarized photon as two component spinor of spherical harmonics. The Geometric Phase of a polarized photon has been evaluated in two ways: the phase two-form of the dielectric matrix through a twist and the Pancharatnam phase (GP) by changing the angular momentum of the incident polarized photon over a closed triangular path on the extended Poincare sphere. The helicity in connection with the spin angular momentum of the chiral photon plays the key role in developing these phase holonomies. (author)

  20. The effects of PbZn1/3Nb2/3O3-doping on structural, thermal, optical, dielectric, and ferroelectric properties of BaTiO3 ceramics

    Science.gov (United States)

    Suchanicz, J.; Świerczek, K.; Sitko, D.; Czaja, P.; Marchet, P.; Czternastek, H.; Majda, D.

    2017-09-01

    Low-lead (1-x)BT-xPZN (x = 0, 0.025, 0.05, 0.075, 0.10, 0.125, and 0.15) ceramics were successfully synthesized by the spark-plasma-sintering method for the first time. Their phase transition behavior as well as structural, thermal, optical, and electrical properties was investigated. These materials exhibit the structure of perovskite-type solid solutions and undergo a sequence of phase transitions, typical of pure BaTiO3 (BT). The dielectric test results revealed that with the increase in the PbZn1/3Nb2/3O3 (PZN) content, the frequency dispersion of electric permittivity increases, whilst the dielectric/ferroelectric properties tend to deteriorate, which is characteristic of relaxor-type behavior. Therefore, it is reasonable to suppose that these ceramics progressively lack long-range ordering. These effects are due to the competition between lone-pair electrons' induced changes in the A-O band upon Pb2+ addition and ionic size differences. In general, the transition temperatures observed by dielectric analyses are in good agreement with those obtained from X-ray diffraction and differential scanning calorimetry measurements. The BT-PZN system may help to understand why relaxor behavior appears in perovskite-based materials. It appears that these materials can become a good starting point for the development of new low-lead electronic ceramics.

  1. [Study on Hexagonal Super-Lattice Pattern with Light Spot and Dim Spot in Dielectric Barrier Discharge by Optical Emission Spectra].

    Science.gov (United States)

    Liu, Ying; Dong, Li-fang; Niu, Xue-jiao; Zhang, Chao

    2016-02-01

    The hexagonal super-lattice pattern composed of the light spot and the dim spot is firstly observed and investigated in the discharge of gas mixture of air and argon by using the dielectric barrier discharge device with double water electrodes. It is found that the dim spot is located at the center of its surrounding three light spots by observing the discharge image. Obviously, the brightness of the light spot and the dim spot are different, which indicates that the plasma states of the light spot and the dim spot may be different. The optical emission spectrum method is used to further study the several plasma parameters of the light spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --> B³IIg) are measured, from which the molecule vibration temperatures of the light spot and the dim spot are calculated. Based on the relative intensity ratio of the line at 391.4 nm and the N₂ line at 394.1 nm, the average electron energies of the light spot and the dim spot are investigated. The broadening of spectral line 696.57 nm (2P₂-1S₅) is used to study the electron densities of the light spot and the dim spot. The experiment shows that the molecule vibration temperature, average electron energy and the electron density of the dim spot are higher than those of the light spot in the same argon content. The molecule vibration temperature and electron density of the light spot and dim spot increase with the argon content increasing from 70% to 95%, while average electron energies of the light spot and dim spot decrease gradually. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The surface discharge induced by the volume discharge (VD) has the decisive effect on the formation of the dim spot. The experiment above plays an important role in studying the formation mechanism of the hexagonal super-lattice pattern with light spot and

  2. Computation of Dielectric Response in Molecular Solids for High Capacitance Organic Dielectrics.

    Science.gov (United States)

    Heitzer, Henry M; Marks, Tobin J; Ratner, Mark A

    2016-09-20

    The dielectric response of a material is central to numerous processes spanning the fields of chemistry, materials science, biology, and physics. Despite this broad importance across these disciplines, describing the dielectric environment of a molecular system at the level of first-principles theory and computation remains a great challenge and is of importance to understand the behavior of existing systems as well as to guide the design and synthetic realization of new ones. Furthermore, with recent advances in molecular electronics, nanotechnology, and molecular biology, it has become necessary to predict the dielectric properties of molecular systems that are often difficult or impossible to measure experimentally. In these scenarios, it is would be highly desirable to be able to determine dielectric response through efficient, accurate, and chemically informative calculations. A good example of where theoretical modeling of dielectric response would be valuable is in the development of high-capacitance organic gate dielectrics for unconventional electronics such as those that could be fabricated by high-throughput printing techniques. Gate dielectrics are fundamental components of all transistor-based logic circuitry, and the combination high dielectric constant and nanoscopic thickness (i.e., high capacitance) is essential to achieving high switching speeds and low power consumption. Molecule-based dielectrics offer the promise of cheap, flexible, and mass producible electronics when used in conjunction with unconventional organic or inorganic semiconducting materials to fabricate organic field effect transistors (OFETs). The molecular dielectrics developed to date typically have limited dielectric response, which results in low capacitances, translating into poor performance of the resulting OFETs. Furthermore, the development of better performing dielectric materials has been hindered by the current highly empirical and labor-intensive pace of synthetic

  3. Selective inorganic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T. [Sandia National Laboratories, Albuquerque, NM (United States)] [and others

    1995-05-01

    This project is developing inorganic thin films as membranes for gas separation applications, and as discriminating coatings for liquid-phase chemical sensors. Our goal is to synthesize these coatings with tailored porosity and surface chemistry on porous substrates and on acoustic and optical sensors. Molecular sieve films offer the possibility of performing separations involving hydrogen, air, and natural gas constituents at elevated temperatures with very high separation factors. We are focusing on improving permeability and molecular sieve properties of crystalline zeolitic membranes made by hydrothermally reacting layered multicomponent sol-gel films deposited on mesoporous substrates. We also used acoustic plate mode (APM) oscillator and surface plasmon resonance (SPR) sensor elements as substrates for sol-gel films, and have both used these modified sensors to determine physical properties of the films and have determined the sensitivity and selectivity of these sensors to aqueous chemical species.

  4. High performance solution processed zirconium oxide gate dielectric appropriate for low temperature device application

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Musarrat; Nguyen, Manh-Cuong; Kim, Hyojin; You, Seung-Won; Jeon, Yoon-Seok; Tong, Duc-Tai; Lee, Dong-Hwi; Jeong, Jae Kyeong; Choi, Rino, E-mail: rino.choi@inha.ac.kr

    2015-08-31

    This paper reports a solution processed electrical device with zirconium oxide gate dielectric that was fabricated at a low enough temperature appropriate for flexible electronics. Both inorganic dielectric and channel materials were synthesized in the same organic solvent. The dielectric constant achieved was 13 at 250 °C with a reasonably low leakage current. The bottom gate transistor devices showed the highest mobility of 75 cm{sup 2}/V s. The device is operated at low voltage with high-k dielectric with excellent transconductance and low threshold voltage. Overall, the results highlight the potential of low temperature solution based deposition in fabricating more complicated circuits for a range of applications. - Highlights: • We develop a low temperature inorganic dielectric deposition process. • We fabricate oxide semiconductor channel devices using all-solution processes. • Same solvent is used for dielectric and oxide semiconductor deposition.

  5. Structural, optical spectroscopy, optical conductivity and dielectric

    Indian Academy of Sciences (India)

    Fe and W co-substituted BaTiO3 perovskite ceramics, compositional formula BaTi ... by the standard solid-state reaction method and studied by X-ray diffraction, ... refractive index, extinction coefficient and absorption coefficient were carried ...

  6. Super dielectric capacitor using scaffold dielectric

    OpenAIRE

    Phillips, Jonathan

    2018-01-01

    Patent A capacitor having first and second electrodes and a scaffold dielectric. The scaffold dielectric comprises an insulating material with a plurality of longitudinal channels extending across the dielectric and filled with a liquid comprising cations and anions. The plurality of longitudinal channels are substantially parallel and the liquid within the longitudinal channels generally has an ionic strength of at least 0.1. Capacitance results from the migrations of...

  7. Electronic structure calculations and optical properties of a new organic-inorganic luminescent perovskite: (C{sub 9}H{sub 19}NH{sub 3}){sub 2}PbI{sub 2}Br{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Abid, H., E-mail: haithamlpa@yahoo.fr [Laboratoire de Physique Appliquee, Faculte des sciences, Universite de Sfax (Tunisia); Institut Neel, CNRS-Universite J. Fourier, BP 166, 38042 Grenoble (France); Samet, A.; Dammak, T. [Laboratoire de Physique Appliquee, Faculte des sciences, Universite de Sfax (Tunisia); Mlayah, A. [Centre d' Elaboration de Materiaux et d' Etudes Structurales (CEMES), CNRS-Universite de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse (France); Hlil, E.K. [Institut Neel, CNRS-Universite J. Fourier, BP 166, 38042 Grenoble (France); Abid, Y. [Laboratoire de Physique Appliquee, Faculte des sciences, Universite de Sfax (Tunisia)

    2011-08-15

    (C{sub 9}H{sub 19}NH{sub 3}){sub 2}PbI{sub 2}Br{sub 2} compound is a new crystal belonging to the large hybrid organic-inorganic perovskites compounds family. Optical properties are investigated by optical absorption UV-visible and photoluminescence (PL) techniques. Bands to band absorption peak at 2.44 eV as well as an extremely strong yellow-green photoluminescence emission at 2.17 eV is observed at room temperature. First principle calculations based on the DFT and FLAPW methods combined with LDA approximation are performed as well. Density of state close to the gap is presented and discussed in terms of optical absorption and photoluminescence experimental results. The perfect agreement between experimental data and electronic structure calculations is highlighted. - Highlights: > (C{sub 9}H{sub 19}NH{sub 3}){sub 2}PbI{sub 2}Br{sub 2} compound is a new crystal with strong yellow-green PL emission at 2.17 eV. > Calculations based on DFT and FLAPW method combined with LDA approximation are performed. > Gap, optical transitions and exciton presence were predicted from density of states. > Agreement between experimental data and electronic structure calculations.

  8. Inertial polarization of dielectrics

    OpenAIRE

    Zavodovsky, A. G.

    2011-01-01

    It was proved that accelerated motion of a linear dielectric causes its polarization. Accelerated translational motion of a dielectric's plate leads to the positive charge of the surface facing the direction of motion. Metal plates of a capacitor were used to register polarized charges on a dielectric's surface. Potential difference between the capacitor plates is proportional to acceleration, when acceleration is constant potential difference grows with the increase of a dielectric's area, o...

  9. Optimal Super Dielectric Material

    Science.gov (United States)

    2015-09-01

    plate capacitor will reduce the net field to an unprecedented extent. This family of materials can form materials with dielectric values orders of... Capacitor -Increase Area (A)............8 b. Multi-layer Ceramic Capacitor -Decrease Thickness (d) .......10 c. Super Dielectric Material-Increase...circuit modeling, from [44], and B) SDM capacitor charge and discharge ...................................................22 Figure 15. Dielectric

  10. Structural analysis, optical and dielectric function of [Ba{sub 0.9}Ca{sub 0.1}](Ti{sub 0.9}Zr{sub 0.1})O{sub 3} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Pérez, G., E-mail: guillermo.herrera@cimav.edu.mx, E-mail: damasio.morales@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), S. C. Miguel de Cervantes 120, Chihuahua 31136, Chihuahua (Mexico); Physics of Materials Department, Centro de Investigación en Materiales Avanzados (CIMAV), S. C. Miguel de Cervantes 120, Chihuahua 31136, Chihuahua (Mexico); Morales, D., E-mail: guillermo.herrera@cimav.edu.mx, E-mail: damasio.morales@cimav.edu.mx; Paraguay-Delgado, F.; Reyes-Rojas, A.; Fuentes-Cobas, L. E. [Physics of Materials Department, Centro de Investigación en Materiales Avanzados (CIMAV), S. C. Miguel de Cervantes 120, Chihuahua 31136, Chihuahua (Mexico); Borja-Urby, R. [Centro de Nanociencias Micro y Nanotecnologías, Instituto Politécnico Nacional, 07300 México City (Mexico)

    2016-09-07

    This work presents the identification of inter-band transitions in the imaginary part of the dielectric function (ε{sub 2}) derived from the Kramers–Kronig analysis for [Ba{sub 0.9}Ca{sub 0.1}](Ti{sub 0.9}Zr{sub 0.1})O{sub 3} (BCZT) nanocrystals synthesized by the modified Pechini method. The analysis started with the chemical identification of the atoms that conform BCZT in the valence loss energy region of a high energy-resolution of electron energy loss spectroscopy. The indirect band energy (E{sub g}) was determined in the dielectric response function. This result is in agreement with the UV-Vis technique, and it obtained an optical band gap of 3.16 eV. The surface and volume plasmon peaks were observed at 13.1 eV and 26.2 eV, respectively. The X-ray diffraction pattern and the Rietveld refinement data of powders heat treated at 700 °C for 1 h suggest a tetragonal structure with a space group (P4 mm) with the average crystal size of 35 nm. The average particle size was determined by transmission electron microscopy.

  11. Hexatungstate subunit as building block in the hydrothermal synthesis of organic-inorganic hybrid materials: synthesis, structure and optical properties of Co2(bpy)6 (W6O19)2 (bpy=4,4'-bipyridine)

    International Nuclear Information System (INIS)

    Zhang Lijuan; Wei Yongge; Wang Chongchen; Guo Hongyou; Wang Ping

    2004-01-01

    A hydrothermal reaction of WO 3 , CoCl 2 and 4,4'-bipyridine, yields a novel organic-inorganic hybrid compound, Co 2 (bpy) 6 (W 6 O 19 ) 2 , at 170 deg. C. X-ray single crystal structure determination reveals a two-dimensional covalent structure belonging to monoclinic crystal system, space group C2/c, with cell parameters a=19.971(4) A, b=11.523(2) A, c=16.138(3) A, β=96.49(3) deg., V=3690.0 A 3 and Z=2. The hexatungstate, [W 6 O 19 ] 2- , acts as a building block in bidentate fashion to bridge the Co(II) centers in the crystal structure. The title compound is found to have an optical energy gap of 2.2 eV from UV-Vis-NIR reflectance spectra

  12. Dielectrics in electric fields

    CERN Document Server

    Raju, Gorur G

    2003-01-01

    Discover nontraditional applications of dielectric studies in this exceptionally crafted field reference or text for seniors and graduate students in power engineering tracks. This text contains more than 800 display equations and discusses polarization phenomena in dielectrics, the complex dielectric constant in an alternating electric field, dielectric relaxation and interfacial polarization, the measurement of absorption and desorption currents in time domains, and high field conduction phenomena. Dielectrics in Electric Fields is an interdisciplinary reference and text for professionals and students in electrical and electronics, chemical, biochemical, and environmental engineering; physical, surface, and colloid chemistry; materials science; and chemical physics.

  13. Dielectric properties of hybrid perovskites and drift-diffusion modeling of perovskite cells

    Science.gov (United States)

    Pedesseau, L.; Kepenekian, M.; Sapori, D.; Huang, Y.; Rolland, A.; Beck, A.; Cornet, C.; Durand, O.; Wang, S.; Katan, C.; Even, J.

    2016-03-01

    A method based on DFT is used to obtained dielectric profiles. The high frequency Ɛ∞(z) and the static Ɛs(z) dielectric profiles are compared for 3D, 2D-3D and 2D Hybrid Organic Perovskites (HOP). A dielectric confinement is observed for the 2D materials between the high dielectric constant of the inorganic part and the low dielectric constant of the organic part. The effect of the ionic contribution on the dielectric constant is also shown. The quantum and dielectric confinements of 3D HOP nanoplatelets are then reported. Finally, a numerical simulation based on the SILVACO code of a HOP based solar cell is proposed for various permittivity of MAPbI3.

  14. A study of the microstructure and optical properties of thin lead-dielectric cermet films. Ph.D. Thesis - Va. Polytechnic Inst. and State Univ.

    Science.gov (United States)

    Owen, R. B.

    1972-01-01

    A transmission electron microscopy study involving direct and replicating techniques is directed to a definition of the microstructure of radio frequency-sputtered, thin lead-dielectric cermet films. Once defined, this microstructure is used to obtain theoretical film refractive indices. The Maxwell Garnett theory provides a basis for the theoretical results. Measurements of film transmission and reflectivity are used to obtain rough experimental values for film refractive indices by the Tekucheva method. More exact values are obtained via ellipsometry. The rough Tekucheva values are used to determine the range over which computer calculations interpreting the ellipsometric results must be made. This technique yields accurate values for the film refractive indices.

  15. Lattices of dielectric resonators

    CERN Document Server

    Trubin, Alexander

    2016-01-01

    This book provides the analytical theory of complex systems composed of a large number of high-Q dielectric resonators. Spherical and cylindrical dielectric resonators with inferior and also whispering gallery oscillations allocated in various lattices are considered. A new approach to S-matrix parameter calculations based on perturbation theory of Maxwell equations, developed for a number of high-Q dielectric bodies, is introduced. All physical relationships are obtained in analytical form and are suitable for further computations. Essential attention is given to a new unified formalism of the description of scattering processes. The general scattering task for coupled eigen oscillations of the whole system of dielectric resonators is described. The equations for the  expansion coefficients are explained in an applicable way. The temporal Green functions for the dielectric resonator are presented. The scattering process of short pulses in dielectric filter structures, dielectric antennas  and lattices of d...

  16. Graphene-on-dielectric micromembrane for optoelectromechanical hybrid devices

    DEFF Research Database (Denmark)

    Schmid, Silvan; Bagci, Tolga; Zeuthen, Emil

    2013-01-01

    Due to their exceptional mechanical and optical properties, dielectric silicon nitride (SiN) micromembranes have become the centerpiece of many optomechanical experiments. Efficient capacitive coupling of the membrane to an electrical system would facilitate exciting hybrid optoelectromechanical ...

  17. Growth and optical, magnetic and transport properties of (C4H9NH3)2MCl4 organic-inorganic hybrid films (M = Cu, Sn)

    Science.gov (United States)

    Aruta, C.; Licci, F.; Zappettini, A.; Bolzoni, F.; Rastelli, F.; Ferro, P.; Besagni, T.

    2005-10-01

    Films of (C4H9NH3)2MCl4 (M=Cu and Sn) organic-inorganic hybrid perovskites have been deposited in-situ by a single-source thermal ablation technique on glassy, crystalline and polymeric substrates. Independently of the substrate, the films were well crystallized, c-axis oriented and with a narrow rocking curve of the (0010) reflection (full width at half maximum photoluminescence spectra of typical (C4H9NH3)2SnCl4 films at 12 K had a broad yellow band, which did not correspond to any significant peak in the absorption spectrum. The films were semiconducting down to 250 K or, in the case of the best samples, down to 200 K and became insulating at lower temperature. The resistivity of the best films was (5±1) 104 Ω cm at 300 K, and the energy gap was 1.11 eV.

  18. Synthesis, characterization and optical properties of a high NIR reflecting yellow inorganic pigment: Mo6+ doped Y2Ce2O7 as a cool colorant

    International Nuclear Information System (INIS)

    Vishnu, V.S.; Reddy, M.L.P.

    2010-01-01

    Full text: Pigments possessing the ability to confer high solar reflectance have received considerable attention in recent years. The inorganic class of NIR reflective pigments are mainly metal oxides and are primarily employed in two applications: (i) visual camouflage and (ii) reducing heat build up. More than half of the solar radiation consists of near-infrared radiation (52%), the remaining being 43% visible light and 5% ultraviolet radiation. Over heating due to solar radiation negatively affects comfort in the built environment and contributes substantially to electrical consumption for air conditioning and release of green house gases. A pigment which has strong reflections in the NIR region (780-2500 nm) can be referred to as a 'cool' pigment. However, most of the NIR reflective inorganic pigments particularly yellow (eg. cadmium yellow, lead chromate, chrome titanate yellow etc.) contain toxic metals and hence their consumption is being limited. Replacing them with environmentally benign cool pigments that absorb less NIR radiation can yield coatings similar in color, but with higher NIR reflectance. A new class of yellow inorganic pigments possessing high near-infrared reflectance (above 90% at 1100 nm), having the general formula Y 2 Ce 2-x Mo x O 7+δ (x ranges from 0 to 0.5) were synthesized by traditional solid state route. The synthesized samples were characterized by powder X-ray diffraction, Scanning Electron Microscopy, UV-Vis-NIR Diffuse Reflectance Spectroscopy, CIE 1976Lab color scales and TG/DTA analysis. XRD analysis reveals the existence of a major cubic fluorite phase for the pigment samples. The diffuse reflectance analysis of the pigments shows a significant shift in the absorption edge towards higher wavelengths (from 410 nm to 506 nm) for the molybdenum doped samples in comparison with the parent compound. The band gap of the designed pigments changes from 3.01 to 2.44 eV and displays colors varying from ivory white to yellow. The

  19. On the dielectric and optical properties of surface-anchored metal-organic frameworks: A study on epitaxially grown thin films

    Science.gov (United States)

    Redel, Engelbert; Wang, Zhengbang; Walheim, Stefan; Liu, Jinxuan; Gliemann, Hartmut; Wöll, Christof

    2013-08-01

    We determine the optical constants of two highly porous, crystalline metal-organic frameworks (MOFs). Since it is problematic to determine the optical constants for the standard powder modification of these porous solids, we instead use surface-anchored metal-organic frameworks (SURMOFs). These MOF thin films are grown using liquid phase epitaxy (LPE) on modified silicon substrates. The produced SURMOF thin films exhibit good optical properties; these porous coatings are smooth as well as crack-free, they do not scatter visible light, and they have a homogenous interference color over the entire sample. Therefore, spectroscopic ellipsometry (SE) can be used in a straightforward fashion to determine the corresponding SURMOF optical properties. After careful removal of the solvent molecules used in the fabrication process as well as the residual water adsorbed in the voids of this highly porous solid, we determine an optical constant of n = 1.39 at a wavelength of 750 nm for HKUST-1 (stands for Hong Kong University of Science and Technology-1; and was first discovered there) or [Cu3(BTC)2]. After exposing these SURMOF thin films to moisture/EtOH atmosphere, the refractive index (n) increases to n = 1.55-1.6. This dependence of the optical properties on water/EtOH adsorption demonstrates the potential of such SURMOF materials for optical sensing.

  20. Toward superlensing with metal-dielectric composites and multilayers

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Bundgaard; Thoreson, M.D.; Chen, W.

    2010-01-01

    We report on the fabrication of two types of adjustable, near-field superlens designs: metal–dielectric composites and metal–dielectric multilayer films. We fabricated a variety of films with different materials, thicknesses and compositions. These samples were characterized physically...... and optically to determine their film composition, quality, and optical responses. Our results on metal–dielectric composites indicate that although the real part of the effective permittivity generally follows effective medium theory predictions, the imaginary part does not and substantially higher losses...

  1. The synthesis, characterization and optical properties of Si4+ and Pr4+ doped Y6 MoO12 compounds: environmentally benign inorganic pigments with high NIR reflectance

    International Nuclear Information System (INIS)

    George, Giable; Reddy, M.L.P.

    2010-01-01

    Full text: Much interest has attended roofing materials with high solar reflectance and high thermal emittance, so that interiors stay cool, thereby reducing the demand for air conditioned buildings. The heat producing region of the infrared radiations ranges from 700-1100 nm. Replacing conventional pigments with 'cool pigments' that absorb less NIR radiation can provide coatings similar in color to that of conventional roofing materials, but with higher solar reflectance. NIR reflective pigments have been used in the military, construction, plastics and ink industries. Complex inorganic pigments based on mixed metal oxides (eg., chromium green, cobalt blue, cadmium stannate, lead chromate, cadmium yellow and chrome titanate yellow), which have been used in camouflage, absorb visible light but reflect the NIR portion of incident radiation. However, many of these pigments are toxic and there is a need to develop novel colored, NIR-reflecting inorganic pigments that are less hazardous to the environment. In this work, a series of NIR reflective colored pigments of formula Y 6-x M x MoO 12+δ (where M Si 4+ or Pr 4+ and x ranges from 0 to 1.0) were synthesized by traditional solid-state route and applied to asbestos cement roofing material so as to evaluate their use as 'cool pigments'. The phase purity of the calcined pigment samples were determined using powder X-ray diffraction. The diffuse reflectance of the powdered pigment samples were measured using a UV-Vis-NIR Spectrometer. The Lab color coordinates were evaluated by CIE 1976 color scale. Replacing Si 4+ for Y 3+ in Y 6 MoO 12 changed the color from light-yellow to dark-yellow and the band gap decreased from 2.60 to 2.45 eV due to O 2p -Mo 4d charge transfer transitions. In contrast, replacing Pr 4+ for Y 3+ changed the color from light yellow to dark brown and the band gap shifted from 2.60 to 1.90 eV. The coloring mechanism is based on the introduction of an additional 4f 1 electron energy level of Pr 4

  2. Characterization of dielectric materials

    Energy Technology Data Exchange (ETDEWEB)

    King, Danny J.; Babinec, Susan; Hagans, Patrick L.; Maxey, Lonnie C.; Payzant, Edward A.; Daniel, Claus; Sabau, Adrian S.; Dinwiddie, Ralph B.; Armstrong, Beth L.; Howe, Jane Y.; Wood, III, David L.; Nembhard, Nicole S.

    2017-06-27

    A system and a method for characterizing a dielectric material are provided. The system and method generally include applying an excitation signal to electrodes on opposing sides of the dielectric material to evaluate a property of the dielectric material. The method can further include measuring the capacitive impedance across the dielectric material, and determining a variation in the capacitive impedance with respect to either or both of a time domain and a frequency domain. The measured property can include pore size and surface imperfections. The method can still further include modifying a processing parameter as the dielectric material is formed in response to the detected variations in the capacitive impedance, which can correspond to a non-uniformity in the dielectric material.

  3. Amine-Based Passivating Materials for Enhanced Optical Properties and Performance of Organic-Inorganic Perovskites in Light-Emitting Diodes.

    Science.gov (United States)

    Lee, Seungjin; Park, Jong Hyun; Lee, Bo Ram; Jung, Eui Dae; Yu, Jae Choul; Di Nuzzo, Daniele; Friend, Richard H; Song, Myoung Hoon

    2017-04-20

    The use of hybrid organic-inorganic perovskites in optoelectronic applications are attracting an interest because of their outstanding characteristics, which enable a remarkable enhancement of device efficiency. However, solution-processed perovskite crystals unavoidably contain defect sites that cause hysteresis in perovskite solar cells (PeSCs) and blinking in perovskite light-emitting diodes (PeLEDs). Here, we report significant beneficial effects using a new treatment based on amine-based passivating materials (APMs) to passivate the defect sites of methylammonium lead tribromide (MAPbBr 3 ) through coordinate bonding between the nitrogen atoms and undercoordinated lead ions. This treatment greatly enhanced the PeLED's efficiency, with an external quantum efficiency (EQE) of 6.2%, enhanced photoluminescence (PL), a lower threshold for amplified spontaneous emission (ASE), a longer PL lifetime, and enhanced device stability. Using confocal microscopy, we observed the cessation of PL blinking in perovskite films treated with ethylenediamine (EDA) due to passivation of the defect sites in the MAPbBr 3 .

  4. Inductive dielectric analyzer

    International Nuclear Information System (INIS)

    Agranovich, Daniel; Popov, Ivan; Ben Ishai, Paul; Feldman, Yuri; Polygalov, Eugene

    2017-01-01

    One of the approaches to bypass the problem of electrode polarization in dielectric measurements is the free electrode method. The advantage of this technique is that, the probing electric field in the material is not supplied by contact electrodes, but rather by electromagnetic induction. We have designed an inductive dielectric analyzer based on a sensor comprising two concentric toroidal coils. In this work, we present an analytic derivation of the relationship between the impedance measured by the sensor and the complex dielectric permittivity of the sample. The obtained relationship was successfully employed to measure the dielectric permittivity and conductivity of various alcohols and aqueous salt solutions. (paper)

  5. Method of making dielectric capacitors with increased dielectric breakdown strength

    Science.gov (United States)

    Ma, Beihai; Balachandran, Uthamalingam; Liu, Shanshan

    2017-05-09

    The invention is directed to a process for making a dielectric ceramic film capacitor and the ceramic dielectric laminated capacitor formed therefrom, the dielectric ceramic film capacitors having increased dielectric breakdown strength. The invention increases breakdown strength by embedding a conductive oxide layer between electrode layers within the dielectric layer of the capacitors. The conductive oxide layer redistributes and dissipates charge, thus mitigating charge concentration and micro fractures formed within the dielectric by electric fields.

  6. Optical and dielectric properties of isothermally crystallized nano-KNbO3 in Er3+-doped K2O-Nb2O5-SiO2 glasses.

    Science.gov (United States)

    Chaliha, Reenamoni Saikia; Annapurna, K; Tarafder, Anal; Tiwari, V S; Gupta, P K; Karmakar, Basudeb

    2010-01-01

    Precursor glass of composition 25K(2)O-25Nb(2)O(5)-50SiO(2) (mol%) doped with Er(2)O(3) (0.5 wt% in excess) was isothermally crystallized at 800 degrees C for 0-100 h to obtain transparent KNbO(3) nanostructured glass-ceramics. XRD, FESEM, TEM, FTIRRS, dielectric constant, refractive index, absorption and fluorescence measurements were carried out to analyze the morphology, dielectric, structure and optical properties of the glass-ceramics. The crystallite size of KNbO(3) estimated from XRD and TEM is found to vary in the range 7-23 nm. A steep rise in the dielectric constant of glass-ceramics with heat-treatment time reveals the formation of ferroelectric nanocrystalline KNbO(3) phase. The measured visible photoluminescence spectra have exhibited green emission transitions of (2)H(11/2), (4)S(3/2)-->(4)I(15/2) upon excitation at 377 nm ((4)I(15/2)-->(4)G(11/2)) absorption band of Er(3+) ions. The near infrared (NIR) emission transition (4)I(13/2)-->(4)I(15/2) is detected around 1550 nm on excitation at 980 nm ((4)I(15/2)-->(4)I(11/2)) of absorption bands of Er(3+) ions. It is observed that photoluminescent intensity at 526 nm ((2)H(11/2)-->(4)I(15/2)), 550 nm ((4)S(3/2)-->(4)I(15/2)) and 1550 nm ((4)I(13/2)-->(4)I(15/2)) initially decrease and then gradually increase with increase in heat-treatment time. The measured lifetime (tau(f)) of the (4)I(13/2)-->(4)I(15/2) transition also possesses a similar trend. The measured absorption and fluorescence spectra reveal that the Er(3+) ions gradually enter into the KNbO(3) nanocrystals. Copyright 2009 Elsevier B.V. All rights reserved.

  7. Synthesis, characterization, and anomalous dielectric and conductivity performance of one-dimensional (bdaH)InSe{sub 2} (bda = 1,4-butanediamine)

    Energy Technology Data Exchange (ETDEWEB)

    Du, Ke-Zhao; Hu, Wan-Biao [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, The Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Hu, Bing; Guan, Xiang-Feng [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, The Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Huang, Xiao-Ying, E-mail: xyhuang@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, The Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2011-11-15

    Graphical abstract: Anomalous dielectric and conductivity performance have been observed in the organic-containing indium selenide (bdaH)InSe{sub 2}, which are attributed to the water molecules existing in the crystal boundary rather than phase transition. Highlights: {yields} The title compound is the first example of organic-containing one-dimensional indium selenide. {yields} The anomalous dielectric peak is attributed to water molecules in crystal boundary. {yields} The inorganic and organic components of the title compound are connected via hydrogen bonding to form a supramolecular three-dimensional network. -- Abstract: A new indium selenide, namely (bdaH)InSe{sub 2} (1) (bda = 1,4-butanediamine) has been solvothermally synthesized and structurally characterized. It belongs to the non-centrosymmetric space group Fdd2. Its structure features an infinite one-dimensional anionic chain of [InSe{sub 2}]{sub n}{sup n-} with monoprotonated [bdaH]{sup +} as charge compensating cation. The organic [bdaH]{sup +} cations are joined into a supramolecular one-dimensional chain via N-H...N hydrogen bonding, which further interacts with the inorganic chain via N-H...Se and C-H...Se hydrogen bonding, forming a supramolecular three-dimensional network. Based on such a well-defined structure, the thermal stability, optical, conductivity, and dielectric properties were systematically investigated, showing that dielectric constant, as well as conductivity, had a hump at about 95 {sup o}C, which could be attributed to water molecules in the crystal boundary.

  8. Synthesis, structure and optical limiting effect of a novel inorganic-organic hybrid polymer containing mixed chains of copper(I)/iodine

    International Nuclear Information System (INIS)

    Li Haohong; Chen Zhirong; Li Junqian; Zhan Hongbing; Zhang Wenxuan; Huang Changcang; Ma Cheng; Zhao Bin

    2006-01-01

    In this paper, treatment of N-ethyl-benzo[f]quinolium (ebq) iodide and CuI with excess KI afforded an unusual coordination polymer [(ebq) 2 (Cu 3 I 4 )(CuI 2 )] n (1). 1 crystallizes in tetragonal system, space group P4(2)bc with cell parameters of a=23.2040(6)A, c=6.7393(3)A, V=3628.6(2)A 3 , Z=8, D c =2.622g/c 3 , R 1 =0.0447 and wR 2 =0.0974. A highly interesting feature of 1 is its presence of mixed types of chains [(Cu 3 I 4 ) n - and (CuI 2 ) n - chain] in one crystal lattice based on supramolecular self-assembly directed by cations. The infinite chains (Cu 3 I 4 ) n - and (CuI 2 ) n - in 1 could be described as the edge-sharing arrangement of CuI 4 tetrahedron. Furthermore, IR, EA, UV-Vis, thermal analysis and optical limiting measurements were adopted to characterize polymer 1. The optical limiting experiment shows that the present polymer exhibits a large optical limiting capacity

  9. Nanostructured hydrophobic DC sputtered inorganic oxide coating for outdoor glass insulators

    Energy Technology Data Exchange (ETDEWEB)

    Dave, V. [Department of Electrical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Institute Instrumentation Centre, Indian Institute of Technology, Roorkee, Roorkee 247667 (India); Gupta, H.O. [Department of Electrical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Chandra, R., E-mail: ramesfic@gmail.com [Institute Instrumentation Centre, Indian Institute of Technology, Roorkee, Roorkee 247667 (India)

    2014-03-01

    Graphical abstract: - Highlights: • Deposition of contamination on outdoor glass insulators and its physical and economical consequences were discussed. • Synthesis of nanostructured hydrophobic HfO{sub 2} film on glass as a remedial measure by varying DC sputtering power. • Investigated and correlated structural, optical, electrical and hydrophobic properties of HfO{sub 2} films with respect to power. • Optimum results were obtained at a 50 W DC sputtering power. - Abstract: We report the structural, optical and electrical properties of nanostructured hydrophobic inorganic hafnium oxide coating for outdoor glass insulator using DC sputtering technique to combat contamination problem. The properties were studied as a function of DC power. The characterization of the films was done using X-ray diffraction, EDS, surface profilometer, AFM, impedance analyser and water contact angle measurement system. The DC power was varied from 30 to 60 W and found to have a great impact on the properties of hafnium oxide. All the deposited samples were polycrystalline with nanostructured hydrophobic surfaces. The intensity of crystallinity of the film was found to be dependent on sputtering power and hydrophobicity was correlated to the nanoscale roughness of the films. The optical property reveals 80% average transmission for all the samples. The refractive index was found in the range of 1.85–1.92, near to the bulk value. The band gap calculated from transmission data was >5.3 eV for all deposited samples ensuring dielectric nature of the films. Surface energy calculated by two methods was found minimum for the film deposited at 50 W sputtering power. The resistivity was also high enough (∼10{sup 4} Ω cm) to hinder the flow of leakage current through the film. The dielectric constant (ε) was found to be thickness dependent and also high enough (ε{sub max} = 23.12) to bear the large electric field of outdoor insulators.

  10. Optics

    CERN Document Server

    Mathieu, Jean Paul

    1975-01-01

    Optics, Parts 1 and 2 covers electromagnetic optics and quantum optics. The first part of the book examines the various of the important properties common to all electromagnetic radiation. This part also studies electromagnetic waves; electromagnetic optics of transparent isotropic and anisotropic media; diffraction; and two-wave and multi-wave interference. The polarization states of light, the velocity of light, and the special theory of relativity are also examined in this part. The second part is devoted to quantum optics, specifically discussing the classical molecular theory of optical p

  11. Studies on the growth aspects, structural, thermal, dielectric and third order nonlinear optical properties of solution grown 4-methylpyridinium p-nitrophenolate single crystal

    Science.gov (United States)

    Devi, S. Reena; Kalaiyarasi, S.; Zahid, I. MD.; Kumar, R. Mohan

    2016-11-01

    An ionic organic optical crystal of 4-methylpyridinium p-nitrophenolate was grown from methanol by slow evaporation method at ambient temperature. Powder and single crystal X-ray diffraction studies revealed the crystal system and its crystalline perfection. The rocking curve recorded from HRXRD study confirmed the crystal quality. FTIR spectral analysis confirmed the functional groups present in the title compound. UV-visible spectral study revealed the optical window and band gap of grown crystal. The thermal, electrical and surface laser damage threshold properties of harvested crystal were examined by using TGA/DTA, LCR/Impedance Analyzer and Nd:YAG laser system respectively. The third order nonlinear optical property of grown crystal was elucidated by Z-scan technique.

  12. Dielectric Modulated FET (DMFET)

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Working Principle: Change in Dielectric constant due to immobilization of biomolecules in the nanogap cavity leads to change in effective gate capacitance and thus gate bias for FET. Working Principle: Change in Dielectric constant due to immobilization of biomolecules in the ...

  13. Thermal dielectric function

    International Nuclear Information System (INIS)

    Moneta, M.

    1999-01-01

    Thermal dielectric functions ε(k,ω) for homogeneous electron gas were determined and discussed. The ground state of the gas is described by the Fermi-Dirac momentum distribution. The low and high temperature limits of ε(k,ω) were related to the Lindhard dielectric function and to ε(k, omega) derived for Boltzmann and for classical momentum distributions, respectively. (author)

  14. Light in complex dielectrics

    NARCIS (Netherlands)

    Schuurmans, F.J.P.

    1999-01-01

    In this thesis the properties of light in complex dielectrics are described, with the two general topics of "modification of spontaneous emission" and "Anderson localization of light". The first part focuses on the spontaneous emission rate of an excited atom in a dielectric host with variable

  15. PREFACE: Dielectrics 2009: Measurement Analysis and Applications

    Science.gov (United States)

    Vaughan, Alun; Williams, Graham

    2009-07-01

    2001 the Annual Meetings focused on numerous topics, including relaxation and conduction processes in liquids, solids, liquid crystals, synthetic polymers and biopolymers, piezoelectric materials, electrets and ferroelectrets, interfacial phenomena, high field conduction and breakdown phenomena in solids, liquids and gases and, importantly, the remarkable developments in dielectric instrumentation during this period. These activities reflected the need, and willingness, to move dielectrics researches with the times. As examples of the variety and diversity of these meetings we may refer briefly to the 1981, 1989 and 1996 Meetings. The 1981 Oxford Meeting on High Field Phenomena in Dielectrics included strong themes on fundamental and practical effects of high E-fields on the dielectric and conduction behaviour of liquids and solids, electrical treeing and dielectric breakdown, non-linear dielectric effects, electrets, thin-film devices and electro-rheology. The late 1980's had seen large initiatives in the UK and globally in the general area of Molecular Electronics so, in timely fashion, this was the subject of the 1989 Meeting in Bangor. The 1996 Smart Dielectrics Meeting at Canterbury reported subsequent advances in designer materials having electro-responsive and electro-optical properties. The programme concerned electro- and photo-active materials, mainly organic, in the form of polar dielectrics, polyelectrolytes, organic semi- and photo-conductors, photo-refractive polymer films, organic ferroelectric films, liquid crystalline polymer films, piezo- and pyro-electric polymer films, electroluminescent polymers, electro-rheological fluids and non-linear optical polymer films as described by leading international scientists. The physico-chemical functions of the materials were demonstrated and interpreted in terms of fundamental molecular properties. An Archive, containing full details of all the Meetings of the DDG and the Dielectrics Society, has been placed on

  16. Studies on metal-dielectric plasmonic structures.

    Energy Technology Data Exchange (ETDEWEB)

    Chettiar, Uday K. (Purdue University, West Lafayette, IN); Liu, Zhengtong (Purdue University, West Lafayette, IN); Thoreson, Mark D. (Purdue University, West Lafayette, IN); Shalaev, Vladimir M. (Purdue University, West Lafayette, IN); Drachev, Vladimir P. (Purdue University, West Lafayette, IN); Pack, Michael Vern; Kildishev, Alexander V. (Purdue University, West Lafayette, IN); Nyga, Piotr (Purdue University, West Lafayette, IN)

    2010-01-01

    The interaction of light with nanostructured metal leads to a number of fascinating phenomena, including plasmon oscillations that can be harnessed for a variety of cutting-edge applications. Plasmon oscillation modes are the collective oscillation of free electrons in metals under incident light. Previously, surface plasmon modes have been used for communication, sensing, nonlinear optics and novel physics studies. In this report, we describe the scientific research completed on metal-dielectric plasmonic films accomplished during a multi-year Purdue Excellence in Science and Engineering Graduate Fellowship sponsored by Sandia National Laboratories. A variety of plasmonic structures, from random 2D metal-dielectric films to 3D composite metal-dielectric films, have been studied in this research for applications such as surface-enhanced Raman sensing, tunable superlenses with resolutions beyond the diffraction limit, enhanced molecular absorption, infrared obscurants, and other real-world applications.

  17. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  18. Determination and analysis of dispersive optical constants of some organic thin films

    International Nuclear Information System (INIS)

    Kaya, Y.; Taysioglu, A. A.; Peksoez, A.; Irez, G.; Derebasi, N.; Kaynak, G.

    2010-01-01

    Schiff bases are an important class of ligands in coordination chemistry and find extensive application in different fields. Recently, increased interest in organic thin film materials has arisen due to their extensive applications in the fields of mechanics, flexible electronics and optics. Optoelectronics is the area in which organic films and organic-inorganic nanostructures have found their main applications in the last decade. These organic thin films have been also used in a wide variety of applications such as Schottky diodes, solid state devices and optical sensors. The optical constants (refractive index, n; extinction coefficient, k and dielectric constant, e) of some organic thin films were determined using reflectance and transmittance spectra. Analysis of the basis absorption spectra was also carried out to determine optical band gap (Eg) and Urbach parameter (E0). A surface observation of these thin films was also carried out by an Atomic Force Microscope.

  19. Layered inorganic solids

    Czech Academy of Sciences Publication Activity Database

    Čejka, Jiří; Morris, R. E.; Nachtigall, P.; Roth, Wieslaw Jerzy

    2014-01-01

    Roč. 43, č. 27 (2014), s. 10274-10275 ISSN 1477-9226 Institutional support: RVO:61388955 Keywords : layered inorganic solids * physical chemistry * catalysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.197, year: 2014

  20. Inorganic Coatings Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The inorganic Coatings Lab provides expertise to Navy and Joint Service platforms acquisition IPTs to aid in materials and processing choices which balance up-front...

  1. Intercalation compounds involving inorganic layered structures

    Directory of Open Access Journals (Sweden)

    CONSTANTINO VERA R. L.

    2000-01-01

    Full Text Available Two-dimensional inorganic networks can shown intracrystalline reactivity, i.e., simple ions, large species as Keggin ions, organic species, coordination compounds or organometallics can be incorporated in the interlayer region. The host-guest interaction usually causes changes in their chemical, catalytic, electronic and optical properties. The isolation of materials with interesting properties and making use of soft chemistry routes have given rise the possibility of industrial and technological applications of these compounds. We have been using several synthetic approaches to intercalate porphyrins and phthalocyanines into inorganic materials: smectite clays, layered double hydroxides and layered niobates. The isolated materials have been characterized by elemental and thermal analysis, X-ray diffraction, surface area measurements, scanning electronic microscopy, electronic and resonance Raman spectroscopies and EPR. The degree of layer stacking and the charge density of the matrices as well their acid-base nature were considered in our studies on the interaction between the macrocycles and inorganic hosts.

  2. Industrial inorganic chemistry. 2. rev. ed.

    International Nuclear Information System (INIS)

    Buechner, W.; Schliebs, R.; Winter, G.; Buechel, K.H.

    1986-01-01

    Inorganic chemistry is a branch of considerable economic and technical importance. Apart from supplying the market with metals, fertilizers, building materials, pigments and glass it is one of the major suppliers of process materials to the organic chemical industry. Many modern products of other industrial sectors (video tapes, optical fibers or silicon chips) could not have been developed and manufactured without the achievements of industrial inorganic chemistry. The publication is the first of its kind to give a compact description of the inorganic chemistry sector. A clearly arranged survey facilitates access to production processes, economic aspects, ecological implications, energy consumption and raw material consumption as well as to many other data and facts. Due to its clear arrangement and the combination of technical and economic facts the book is a valuable source of information. (orig./EF) [de

  3. Inorganic and geological materials

    International Nuclear Information System (INIS)

    Dinnin, J.I.

    1975-01-01

    Recently described methods for applied inorganic analysis are reviewed from an interdisciplinary standpoint. Abstracts and periodical literature up to Nov. 1974, are included for consideration. The following areas of interest are covered: general reviews of inorganic analytical techniques; analytical techniques, areas of application, and analysis of individual elements. Selected books, monographs, and review articles on the analytical chemistry of the elements are listed. (416 references.) (U.S.)

  4. TiN{sub x}O{sub y}/TiN dielectric contrasts obtained by ion implantation of O{sub 2}{sup +}; structural, optical and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Punzon Quijorna, E; Torres Costa, V; Climent, A; Manso Silvan, M [Departamento de Fisica Aplicada. Universidad Autonoma de Madrid, 28049 Madrid (Spain); Agullo-Rueda, F; Herrero Fernandez, P [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid (Spain); Rossi, F [Institute for Health and Consumer Protection, Joint Research Center, 21020 Ispra (Vatican City State, Holy See) (Italy)

    2011-06-15

    The properties of TiN can be gradually transformed by O{sub 2}{sup +} implantations in the 10-40 keV range and fluences in the 5 x 10{sup 13}-5 x 10{sup 16} cm{sup -2} range. The resulting structure consists of shallow TiN{sub x}O{sub y}(TiNO)/TiN contrasts with increased resistivity on the top layer. In fact, oxygen actively replaces nitrogen in the implanted TiN region as illustrated by Rutherford backscattering spectrometry. N substitutions and vacancies in the lattice induce structural distortions and strain generation as illustrated by x-ray diffraction, high resolution transmission electron microscopy and Raman spectroscopy. The influence of these modifications in the optical and electrical properties was characterized by spectroscopic ellipsometry and four probe resistivity measurements. The proposed process, especially at the lower energy, is liable to help in the creation of electrical/photonic structures based in shallow TiNO/TiN electric/dielectric contrasts.

  5. Improved Dielectric Films For Capacitors

    Science.gov (United States)

    Yen, Shiao-Ping S.; Lewis, Carol R.; Cygan, Peter J.; Jow, T. Richard

    1994-01-01

    Dielectric films made from blends of some commercially available high-dielectric-constant cyanoresins with each other and with cellulose triacetate (CTA) have both high dielectric constants and high breakdown strengths. Dielectric constants as high as 16.2. Films used to produce high-energy-density capacitors.

  6. Oblique surface waves at an interface between a metal-dielectric superlattice and an isotropic dielectric

    International Nuclear Information System (INIS)

    Vuković, Slobodan M; Miret, Juan J; Zapata-Rodriguez, Carlos J; Jakšić, Zoran

    2012-01-01

    We investigate the existence and dispersion characteristics of surface waves that propagate at an interface between a metal-dielectric superlattice and an isotropic dielectric. Within the long-wavelength limit, when the effective-medium (EM) approximation is valid, the superlattice behaves like a uniaxial plasmonic crystal with the main optical axes perpendicular to the metal-dielectric interfaces. We demonstrate that if such a semi-infinite plasmonic crystal is cut normally to the layer interfaces and brought into contact with a semi-infinite dielectric, a new type of surface mode can appear. Such modes can propagate obliquely to the optical axes if favorable conditions regarding the thickness of the layers and the dielectric permittivities of the constituent materials are met. We show that losses within the metallic layers can be substantially reduced by making the layers sufficiently thin. At the same time, a dramatic enlargement of the range of angles for oblique propagation of the new surface modes is observed. This can lead, however, to field non-locality and consequently to failure of the EM approximation.

  7. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  8. Robust design of microlenses arrays employing dielectric resonators metasurfaces

    NARCIS (Netherlands)

    Silvestri, F.; Gerini, G.; Bäumer, S.M.B.

    2017-01-01

    In the last years, much interest has grown around the concept of optical surfaces employing high contrast dielectric resonators. However, a systematic approach for the design of this optical surfaces under particular requirements has never been proposed. In this contribution, we describe this

  9. Microwave chemistry: Effect of ions on dielectric heating in microwave ovens

    Directory of Open Access Journals (Sweden)

    Jamil Anwar

    2015-01-01

    Full Text Available To understand the interactions of microwaves with dielectric materials and their conversion to thermal energy in aqueous systems, the effect of ionic concentration has been studied. Aqueous solutions of inorganic ions were exposed to microwaves (2.45 GHz in a modified oven under identical conditions. Difference in solution temperatures with reference to pure (deionized water was monitored in each case. A significant decrease in the temperature was observed with an increase in the quantity of ions. Experiments were repeated with several inorganic ions varying in size and charge. The information can be helpful in understanding the role of ions during dielectric heating.

  10. Dielectric materials for electrical engineering

    CERN Document Server

    Martinez-Vega, Juan

    2013-01-01

    Part 1 is particularly concerned with physical properties, electrical ageing and modeling with topics such as the physics of charged dielectric materials, conduction mechanisms, dielectric relaxation, space charge, electric ageing and life end models and dielectric experimental characterization. Part 2 concerns some applications specific to dielectric materials: insulating oils for transformers, electrorheological fluids, electrolytic capacitors, ionic membranes, photovoltaic conversion, dielectric thermal control coatings for geostationary satellites, plastics recycling and piezoelectric poly

  11. Cast dielectric composite linear accelerator

    Science.gov (United States)

    Sanders, David M [Livermore, CA; Sampayan, Stephen [Manteca, CA; Slenes, Kirk [Albuquerque, NM; Stoller, H M [Albuquerque, NM

    2009-11-10

    A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.

  12. Simultaneous monitoring of biofilm growth, microbial activity, and inorganic deposits on surfaces with an in situ, online, real-time, non-destructive, optical sensor.

    Science.gov (United States)

    Strathmann, Martin; Mittenzwey, Klaus-Henrik; Sinn, Gert; Papadakis, Wassilios; Flemming, Hans-Curt

    2013-01-01

    Deposits on surfaces in water-bearing systems, also known as 'fouling', can lead to substantial losses in the performance of industrial processes as well as a decreased product quality. Early detection and localization of such deposits can, to a considerable extent, save such losses. However, most of the surfaces that become fouled, for example, in process water pipes, membrane systems, power plants, and food and beverage industries, are difficult to access and analyses conducted on the water phase do not reveal the site or extent of deposits. Furthermore, it is of interest to distinguish biological from non-biological deposits. Although they usually occur together, different countermeasures are necessary. Therefore, sensors are required that indicate the development of surface fouling in real-time, non-destructively, and in situ, preferably allowing for discrimination between chemical and/or biological deposits. In this paper, an optical deposit sensor is presented which fulfills these requirements. Based on multiple fluorescence excitation emission matrix analysis, it detects autofluorescence of amino acids as indicators of biomass. Autofluorescence of nicotinamide adenine dinucleotide + hydrogen is interpreted as an indicator of biological activity, thus it acts as a viability marker, making the method suited for assessing the efficacy of disinfection treatments. Scattering signals from abiotic deposits such as calcium carbonate or corrosion products can clearly be distinguished from biotic substances and monitored separately. The sensor provides an early warning of fouling, allowing for timely countermeasures to be deployed. It also provides an assessment of the success of cleaning treatments and is a promising tool for integrated antifouling strategies.

  13. Parameterization of the dielectric function of semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Petrik, P., E-mail: petrik@mfa.kfki.hu

    2014-11-15

    Optical methods like spectroscopic ellipsometry are sensitive to the structural properties of semiconductor films such as crystallinity or grain size. The imaginary part of the dielectric function is proportional to the joint density of electronic states. Consequently, the analysis of the dielectric function around the critical point energies provides useful information about the electron band structure and all related parameters like the grain structure, band gap, temperature, composition, phase structure, and carrier mobility. In this work an attempt is made to present a selection of the approaches to parameterize and analyze the dielectric function of semiconductors, as well as some applications.

  14. Dielectric properties of PMMA-SiO2 hybrid films

    KAUST Repository

    Morales-Acosta, M. D.; Quevedo-Ló pez, Manuel Angel Quevedo; Alshareef, Husam N.; Gnade, Bruce E.; Ramí rez-Bon, Rafael

    2010-01-01

    Organic-inorganic hybrid films were synthesized by a modified sol-gel process. PMMASiO2 films were prepared using methylmethacrylate (MMA), tetraethil-orthosilicate (TEOS) as silicon dioxide source, and 3-trimetoxi-silil-propil-methacrylate (TMSPM) as coupling agent. FTIR measurements were performed on the hybrid films to confirm the presence of PMMA-SiO2 bonding. In addition, metal-insulator-metal (MIM) devices were fabricated to study the dielectric constant of the films as function of frequency (1 KHz to 1 MHz). Electrical results show a weak trend of the dielectric constant of the hybrid films with MMA molar ratio. More importantly, the PMMA-SiO2 hybrid films showed a higher dielectric constant than SiO2 and PMMA layers, which is likely due to the presence of additional C-O-C bond. © (2010) Trans Tech Publications.

  15. Dielectric properties of PMMA-SiO2 hybrid films

    KAUST Repository

    Morales-Acosta, M. D.

    2010-03-01

    Organic-inorganic hybrid films were synthesized by a modified sol-gel process. PMMASiO2 films were prepared using methylmethacrylate (MMA), tetraethil-orthosilicate (TEOS) as silicon dioxide source, and 3-trimetoxi-silil-propil-methacrylate (TMSPM) as coupling agent. FTIR measurements were performed on the hybrid films to confirm the presence of PMMA-SiO2 bonding. In addition, metal-insulator-metal (MIM) devices were fabricated to study the dielectric constant of the films as function of frequency (1 KHz to 1 MHz). Electrical results show a weak trend of the dielectric constant of the hybrid films with MMA molar ratio. More importantly, the PMMA-SiO2 hybrid films showed a higher dielectric constant than SiO2 and PMMA layers, which is likely due to the presence of additional C-O-C bond. © (2010) Trans Tech Publications.

  16. Inorganic UV filters

    Directory of Open Access Journals (Sweden)

    Eloísa Berbel Manaia

    2013-06-01

    Full Text Available Nowadays, concern over skin cancer has been growing more and more, especially in tropical countries where the incidence of UVA/B radiation is higher. The correct use of sunscreen is the most efficient way to prevent the development of this disease. The ingredients of sunscreen can be organic and/or inorganic sun filters. Inorganic filters present some advantages over organic filters, such as photostability, non-irritability and broad spectrum protection. Nevertheless, inorganic filters have a whitening effect in sunscreen formulations owing to the high refractive index, decreasing their esthetic appeal. Many techniques have been developed to overcome this problem and among them, the use of nanotechnology stands out. The estimated amount of nanomaterial in use must increase from 2000 tons in 2004 to a projected 58000 tons in 2020. In this context, this article aims to analyze critically both the different features of the production of inorganic filters (synthesis routes proposed in recent years and the permeability, the safety and other characteristics of the new generation of inorganic filters.

  17. Crystallization kinetics, optical and dielectric properties of Li2OṡCdOṡBi2O3ṡSiO2 glasses

    Science.gov (United States)

    Rani, Saroj; Sanghi, Sujata; Ahlawat, Neetu; Agarwal, Ashish

    2015-10-01

    Crystallization kinetics, optical absorption and electrical behavior of lithium cadmium silicate glasses with different amount of bismuth oxide were investigated using non-isothermal crystallization approach, UV-VIS-NIR spectroscopy and impedance spectroscopy, respectively. These glasses were synthesized by normal melt quenching technique. Variation in physical properties, viz. density, molar volume with Bi2O3:SiO2 ratio were related to the structural changes occurring in the glasses. The glass transition temperature (Tg), crystalline peak temperature (Tp) and melting temperature (Tm) of these glasses were determined using differential scanning calorimeter at various heating rates. The dependence of Tg and Tp on heating rate has been used for the determination of the activation energy of glass transition and crystallization. Thermal stability parameters have revealed high stability of the glass prepared with 40 mol% of Bi2O3 content. The crystallization kinetics for the glasses was studied by using the Kissinger and modified Ozawa equations. Appearance of a sharp cut-off and a wide and reasonable transmission in VIS-NIR region makes these glasses suitable for IR transmission window. The cut-off wavelength, optical band gap and Urbach's energy have been analyzed and discussed in terms of changes in the glass structure. By analyzing the impedance spectra, the ac and dc conductivities, activation energy for dc conduction (Edc) and for relaxation (EM″) were calculated. The results obtained from dc conductivity confirm the network forming role of Cd2+ ion in the glasses. The scaling of the conductivity spectra has been used to interpret the temperature dependence of the relaxation dynamics. The observed conductivity spectra follows power law with exponent 's' which decreases with temperature and satisfies the correlated barrier hopping (CBH) model. The perfect overlying of normalized plots of electrical modulus on a single 'master curve' depicts temperature as well as

  18. Strong room-temperature ultraviolet to red excitons from inorganic organic-layered perovskites, (MX4 (M=Pb, Sn, Hg; X=I-, Br-)

    Science.gov (United States)

    Ahmad, Shahab; Prakash, G. Vijaya

    2014-01-01

    Many varieties of layered inorganic-organic (IO) perovskite of type (MX4 (where R: organic moiety, M: divalent metal, and X: halogen) were successfully fabricated and characterized. X-ray diffraction data suggest that these inorganic and organic structures are alternatively stacked up along c-axis, where inorganic mono layers are of extended corner-shared MX6 octahedra and organic spacers are the bi-layers of organic entities. These layered perovskites show unusual room-temperature exciton absorption and photoluminescence due to the quantum and dielectric confinement-induced enhancement in the exciton binding energies. A wide spectral range of optical exciton tunability (350 to 600 nm) was observed experimentally from systematic compositional variation in (i) divalent metal ions (M=Pb, Sn, Hg), (ii) halides (X=I and Br-), and (iii) organic moieties (R). Specific photoluminescence features are due to the structure of the extended MX42- network and the eventual electronic band structure. The compositionally dependent photoluminescence of these IO hybrids could be useful in various photonic and optoelectronic devices.

  19. Inorganic liquid scintillator

    International Nuclear Information System (INIS)

    Pavlicek, Z.; Barta, C.; Jursova, L.

    1986-01-01

    An inorganic liquid scintillator is designed which contains 1 to 30 wt.% of an inorganic molecular compound as the basic active component; the compound contains a cation with an atomic number higher than 47 and a halogen anion. The basic inorganic component is dissolved in water or in an organic solvent in form of non-dissociated molecules or self-complexes in which the bond is preserved between the cation and anion components. The light yield from these scintillators ranges between 70 and 150% of the light yield of a standard organic scintillator based on toluene. They are advantageous in that that they allow to increase the water content in the sample to up to 100%. (M.D.)

  20. Synthesis, crystal structure, vibrational spectroscopy, optical properties and theoretical studies of a new organic-inorganic hybrid material: [((CH3)2NH2)(+)]6·[(BiBr6)(3-)]2.

    Science.gov (United States)

    Ben Ahmed, A; Feki, H; Abid, Y

    2014-12-10

    A new organic-inorganic hybrid material, [((CH3)2NH2)(+)]6·[(BiBr6)(3-)]2, has been synthesized and characterized by X-ray diffraction, FT-IR, Raman spectroscopy and UV-Visible absorption. The studied compound crystallizes in the triclinic system, space group P1¯ with the following parameters: a=8.4749(6)(Å), b=17.1392(12)(Å), c=17.1392(12)(Å), α=117.339(0)°, β=99.487(0)°, γ=99.487(0)° and Z=2. The crystal lattice is composed of a two discrete (BiBr6)(3-) anions surrounded by six ((CH3)2NH2)(+) cations. Complex hydrogen bonding interactions between (BiBr6)(3-) and organic cations from a three-dimensional network. Theoretical calculations were performed using density functional theory (DFT) for studying the molecular structure, vibrational spectra and optical properties of the investigated molecule in the ground state. The full geometry optimization of designed system is performed using DFT method at B3LYP/LanL2DZ level of theory using the Gaussian03. The optimized geometrical parameters obtained by DFT calculations are in good agreement with single crystal XRD data. The vibrational spectral data obtained from FT-IR and Raman spectra are assigned based on the results of the theoretical calculations. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) results complements with the experimental findings. The simulated spectra satisfactorily coincide with the experimental UV-Visible spectrum. The results show good consistent with the experiment and confirm the contribution of metal orbital to the HOMO-LUMO boundary. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Thorium inorganic gels

    International Nuclear Information System (INIS)

    Genet, M.; Brandel, V.

    1988-01-01

    The optimum pH and concentration values of thorium salts and oxoacids or oxoacid salts which lead to transparent and stable inorganic gels have been determined. The isotherm drying process of the gel at 50 0 C leads successively to a partly dehydrated gel, then, to the formation of an unusual liquid phase and, finally to a dry amorphous solid phase which is still transparent. This kind of transparent inorganic gels and amorphous phase can be used as matrices for spectroscopic studies [fr

  2. Neutron Diffraction and Inorganic Materials Discovery

    International Nuclear Information System (INIS)

    Rosseinsky, M.J.

    2005-01-01

    Full text: The discovery of complex inorganic materials is an important academic and technological challenge because of the opportunities these systems offer for observation of new phenomena, and the questions they pose for fundamental understanding. This presentation will illustrate the key role of neutron powder diffraction in enabling the discovery of new classes of materials, and in evaluating their properties and the conditions under which they need to be processed to optimise their behaviour in devices for applications. New chemistry is illustrated by the transition metal oxide hydrides, where both structure and ionic mobility required neutron scattering characterisation. The relationship between chemistry, structure and properties will be addressed by considering the difficulties in inducing superconductivity in analogues of magnesium diboride. The role of both neutron and X-ray diffraction in evaluating the processing of microwave dielectric ceramics will be highlighted, with the discovery of new phases shown to be a useful bonus in this type of in-situ study. (author)

  3. Coexisting Ferromagnetic and Ferroelectric Order in a CuCl4-based Organic-Inorganic Hybrid

    NARCIS (Netherlands)

    Polyakov, Alexey O.; Arkenbout, Anne H.; Baas, Jacob; Blake, Graeme R.; Meetsma, Auke; Caretta, Antonio; van Loosdrecht, Paul H. M.; Palstra, Thomas T. M.

    2012-01-01

    We investigate the structural, magnetic, and dielectric properties of the organic-inorganic hybrid material CuCl4(C6H5CH2CH2NH3)(2) and demonstrate that spontaneous ferroelectric order sets in below 340 K, which coexists with ferromagnetic ordering below 13 K. We use X-ray diffraction to show that

  4. Plane-wave diffraction by periodic structures with artificial anisotropic dielectrics

    International Nuclear Information System (INIS)

    Kazerooni, Azadeh Semsar; Shahabadi, Mahmoud

    2010-01-01

    Periodic structures with artificial anisotropic dielectrics are studied. The artificial anisotropic dielectric material in this work is made of two alternating isotropic dielectric layers. By a proper choice of the dielectric constant of the layers, we can realize a uniaxial anisotropic medium with controllable anisotropy. The artificial anisotropic dielectric is then used in periodic structures. For these structures, the optical axis of the artificial dielectric is assumed to be parallel or perpendicular to the period of the structure. Diffraction of plane waves by these structures is analyzed by a fully vectorial rigorous matrix method based on a generalized transmission line (TL) formulation. The propagation constants and field distributions are computed and diffraction properties of such structures are studied to show that, by a proper choice of structural parameters, these periodic structures with artificial anisotropic dielectrics can be used as polarizers or polarizing mirrors

  5. Electromagnetically induced transparency with wide band in all-dielectric microstructure based on Mie resonances

    International Nuclear Information System (INIS)

    Zhu, Lei; Dong, Liang

    2014-01-01

    We numerically demonstrate that a broadband electromagnetically induced transparency–like (EIT-like) effect can be achieved in an all-dielectric microstructure consisting of a dielectric bar and six dielectric bricks. With proper excitations, the dielectric bar and bricks serve as bright and dark elements via the Mie electric and magnetic resonances, respectively. In particular, the mutual couplings between the Mie electric and magnetic resonances induce a broad transparency window. The nature of resonances of the broadband EIT-like effect in an all-dielectric microstructure is investigated by numerical simulation and a coupled oscillator model. Results reveal that significant enhancement of coupling interactions between dielectric resonators leads to a broadband EIT-like effect. Such a dielectric EIT-like structure is promising for future applications in nonlinear optics, slow light devices, and filters. (paper)

  6. Engineered inorganic core/shell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mélinon, Patrice, E-mail: patrice.melinon@univ-lyon1.fr [Institut Lumière matière Université Claude Bernard Lyon 1 et CNRS et OMNT, Domaine Scientifique de la Doua, Bâtiment Léon Brillouin, 43 Boulevard du 11 Novembre 1918, F 69622 Villeurbanne (France); Begin-Colin, Sylvie [IPCMS et OMNT, 23 rue du Loess BP 43, 67034 STRASBOURG Cedex 2 (France); Duvail, Jean Luc [IMN UMR 6502 et OMNT Campus Sciences : 2 rue de la Houssinire, BP32229, 44322 Nantes Cedex3 (France); Gauffre, Fabienne [SPM et OMNT : Institut des sciences chimiques de Rennes - UMR 6226, 263 Avenue du General Leclerc, CS 74205, 35042 RENNES Cedex (France); Boime, Nathalie Herlin [IRAMIS-NIMBE, Laboratoire Francis Perrin (CEA CNRS URA 2453) et OMNT, Bat 522, CEA Saclay, 91191 Gif sur Yvette Cedex (France); Ledoux, Gilles [Institut Lumière Matière Université Claude Bernard Lyon 1 et CNRS et OMNT, Domaine Scientifique de la Doua, Bâtiment Alfred Kastler 43 Boulevard du 11 Novembre 1918 F 69622 Villeurbanne (France); Plain, Jérôme [Universit de technologie de Troyes LNIO-ICD, CNRS et OMNT 12 rue Marie Curie - CS 42060 - 10004 Troyes cedex (France); Reiss, Peter [CEA Grenoble, INAC-SPrAM, UMR 5819 CEA-CNRS-UJF et OMNT, Grenoble cedex 9 (France); Silly, Fabien [CEA, IRAMIS, SPEC, TITANS, CNRS 2464 et OMNT, F-91191 Gif sur Yvette (France); Warot-Fonrose, Bénédicte [CEMES-CNRS, Université de Toulouse et OMNT, 29 rue Jeanne Marvig F 31055 Toulouse (France)

    2014-10-20

    It has been for a long time recognized that nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic structures. At first, size effects occurring in single elements have been studied. More recently, progress in chemical and physical synthesis routes permitted the preparation of more complex structures. Such structures take advantages of new adjustable parameters including stoichiometry, chemical ordering, shape and segregation opening new fields with tailored materials for biology, mechanics, optics magnetism, chemistry catalysis, solar cells and microelectronics. Among them, core/shell structures are a particular class of nanoparticles made with an inorganic core and one or several inorganic shell layer(s). In earlier work, the shell was merely used as a protective coating for the core. More recently, it has been shown that it is possible to tune the physical properties in a larger range than that of each material taken separately. The goal of the present review is to discuss the basic properties of the different types of core/shell nanoparticles including a large variety of heterostructures. We restrict ourselves on all inorganic (on inorganic/inorganic) core/shell structures. In the light of recent developments, the applications of inorganic core/shell particles are found in many fields including biology, chemistry, physics and engineering. In addition to a representative overview of the properties, general concepts based on solid state physics are considered for material selection and for identifying criteria linking the core/shell structure and its resulting properties. Chemical and physical routes for the synthesis and specific methods for the study of core/shell nanoparticle are briefly discussed.

  7. Optimizing a cleaning process for multilayer-dielectric- (MLD) diffraction gratings

    Energy Technology Data Exchange (ETDEWEB)

    Ashe, B. [Univ. of Rochester, NY (United States); Giacofei, C. [Univ. of Rochester, NY (United States); Myhre, G. [Univ. of Rochester, NY (United States); Schmid, A. W. [Univ. of Rochester, NY (United States)

    2007-12-20

    An essential component for the OMEGA EP short-pulse petawatt laser system is the grating compressor chamber (GCC). This large (12,375 ft3) vacuum chamber contains critical optics where laser-pulse compression is performed at the output of the system on two 40-cm-sq-aperture, IR (1054-nm) laser beams. Critical to this compression, within the GCC, are four sets of tiled multilayer-dielectric- (MLD) diffraction gratings that provide the capability for producing 2.6-kJ output IR energy per beam at 10 ps. The primary requirements for these large-aperture (43-cm × 47-cm) gratings are diffraction efficiencies greater than 95%, peak-to-valley wavefront quality of less than λ/10 waves, and laser-induced-damage thresholds greater than 2.7 J/cm2 at 10-ps measured beam normal. Degradation of the grating laser-damage threshold due to adsorption of contaminants from the manufacturing process must be prevented to maintain system performance. In this paper we discuss an optimized cleaning process to achieve the OMEGA EP requirements. The fabrication of MLD gratings involves processes that utilize a wide variety of both organic materials (photoresist processes) and inorganic materials (metals and metal oxides) that can affect the final cleaning process. Finally, a number of these materials have significant optical absorbance; therefore, incomplete cleaning of these residues may result in the MLD gratings experiencing laser damage.

  8. Millimeter wave and terahertz dielectric properties of biological materials

    Science.gov (United States)

    Khan, Usman Ansar

    Broadband dielectric properties of materials can be employed to identify, detect, and characterize materials through their unique spectral signatures. In this study, millimeter wave, submillimeter wave, and terahertz dielectric properties of biological substances inclusive of liquids, solids, and powders were obtained using Dispersive Fourier Transform Spectroscopy (DFTS). Two broadband polarizing interferometers were constructed to test materials from 60 GHz to 1.2 THz. This is an extremely difficult portion of the frequency spectrum to obtain a material's dielectric properties since neither optical nor microwave-based techniques provide accurate data. The dielectric characteristics of liquids such as cyclohexane, chlorobenzene, benzene, ethanol, methanol, 1,4 dioxane, and 10% formalin were obtained using the liquid interferometer. Subsequently the solid interferometer was utilized to determine the dielectric properties of human breast tissues, which are fixed and preserved in 10% formalin. This joint collaboration with the Tufts New England Medical Center demonstrated a significant difference between the dielectric response of tumorous and non-tumorous breast tissues across the spectrum. Powders such as anthrax, flour, talc, corn starch, dry milk, and baking soda have been involved in a number of security threats and false alarms around the globe in the last decade. To be able to differentiate hoax attacks and serious security threats, the dielectric properties of common household powders were also examined using the solid interferometer to identify the powders' unique resonance peaks. A new sample preparation kit was designed to test the powder specimens. It was anticipated that millimeter wave and terahertz dielectric characterization will enable one to clearly distinguish one powder from the other; however most of the powders had relatively close dielectric responses and only Talc had a resonance signature recorded at 1.135 THz. Furthermore, due to

  9. Synthesis, vibrational and optical properties of a new three-layered organic-inorganic perovskite (C{sub 4}H{sub 9}NH{sub 3}){sub 4}Pb{sub 3}I{sub 4}Br{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Dammak, T., E-mail: thameurlpa@yahoo.f [Laboratoire de Physique appliquee (LPA), Faculte des Sciences de Sfax, 3018, BP 802 (Tunisia); Elleuch, S. [Laboratoire de Physique appliquee (LPA), Faculte des Sciences de Sfax, 3018, BP 802 (Tunisia); Bougzhala, H. [Laboratoire de cristallochimie et des materiaux, Faculte des Sciences de Tunis (Tunisia); Mlayah, A. [Centre d' Elaboration de Materiaux et d' Etudes Structurales, CNRS-Universite Paul Sabatier, 29 rue Jeanne Marvig, 31055 Toulouse, Cedex 4 (France); Chtourou, R. [Centre de Recherche et des Technologies de l' Energie CRTEn BP. 95, Hammam-Lif 2050, Laboratoire de Photovoltaique et de Semiconducteur (Tunisia); Abid, Y. [Laboratoire de Physique appliquee (LPA), Faculte des Sciences de Sfax, 3018, BP 802 (Tunisia)

    2009-09-15

    An organic-inorganic hybrid perovskite (C{sub 4}H{sub 9}NH{sub 3}){sub 4}Pb{sub 3}I{sub 4}Br{sub 6} was synthesized and studied by X-ray diffraction, Raman and infrared spectroscopies, optical transmission and photoluminescence. The title compound, abbreviated (C{sub 4}){sub 4}Pb{sub 3}I{sub 4}Br{sub 6}, crystallises in a periodic two-dimensional multilayer structure with P2{sub 1}/a space group. The structure is built up from alternating inorganic and organic layers. Each inorganic layer consists of three sheets of PbX{sub 6} (X=I, Br) octahedra. Raman and infrared spectra of the title compound were recorded in the 100-3500 and 400-4000 cm{sup -1} frequency ranges, respectively. An assignment of the observed vibration modes is reported. Optical transmission measurements, performed on thin films of (C{sub 4}){sub 4}Pb{sub 3}I{sub 4}Br{sub 6}, revealed two absorption bands at 474 and 508 nm. Photoluminescence measurements have shown a green emission peak at 519 nm.

  10. Holographic patterning of organic-inorganic photopolymerizable nanocomposites

    Science.gov (United States)

    Sakhno, Oksana V.; Goldenberg, Leonid M.; Smirnova, Tatiana N.; Stumpe, J.

    2009-09-01

    We present here novel easily processible organic-inorganic nanocomposites suitable for holographic fabrication of diffraction optical elements (DOE). The nanocomposites are based on photocurable acrylate monomers and inorganic nanoparticles (NP). The compatibility of inorganic NP with monomers was achieved by capping the NP surface with proper organic shells. Surface modification allows to introduce up to 50wt.% of inorganic NP in organic media. Depending on the NP nature (metal oxides, phosphates, semiconductors, noble metals) and their properties, the materials for both efficient DOE and multifunctional elements can be designed. Organic-inorganic composites prepared have been successfully used for the effective inscription of periodic volume refractive index structures using the holographic photopolymerization method. The nanocomposite preparation procedure, their properties and optical performance of holographic gratings are reported. The use of functional NP makes it possible to obtain effective holographic gratings having additional physical properties such as light-emission or NLO. Some examples of such functional polymer-NP structures and their possible application fields are presented. The combination of easy photo-patterning of soft organic compounds with physical properties of inorganic materials in new nanocomposites and the flexibility of the holographic patterning method allow the fabrication of mono- and multifunctional one- and multi-dimensional passive or active optical and photonic elements.

  11. Effect of the dielectric constant of mesoscopic particle on the exciton binding energy

    International Nuclear Information System (INIS)

    Lai Zuyou; Gu Shiwei

    1991-09-01

    For materials with big exciton reduced mass and big dielectric constant, such as TiO 2 , the variation of dielectric constant with the radius of an ultrafine particle (UFP) is important for determining the exciton binding energy. For the first time a phenomenological formula of the dielectric constant of a UFP with its radius in mesoscopic range is put forward in order to explain the optical properties of TiO 2 UFP. (author). 22 refs, 3 figs, 1 tab

  12. Plasmonic and Dielectric Metasurfaces: Design, Fabrication and Applications

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2016-09-01

    Full Text Available Two-dimensional metasurfaces are widely focused on for their ability for flexible light manipulation (phase, amplitude, polarization over sub-wavelength propagation distances. Most of the metasurfaces can be divided into two categories by the material type of unit structure, i.e., plasmonic metasurfaces and dielectric metasurfaces. For plasmonic metasurfaces, they are made on the basis of metallic meta-atoms whose optical responses are driven by the plasmon resonances supported by metallic particles. For dielectric metasurfaces, the unit structure is constructed with high refractive index dielectric resonators, such as silicon, germanium or tellurium, which can support electric and magnetic dipole responses based on Mie resonances. The responses of plasmonic and dielectric metasurfaces are all relevant to the characteristics of unit structure, such as dimensions and materials. One can manipulate the electromagnetic field of light wave scattered by the metasurfaces through designing the dimension parameters of each unit structure in the metasurfaces. In this review article, we give a brief overview of our recent progress in plasmonic and dielectric metasurface-assisted nanophotonic devices and their design, fabrication and applications, including the metasurface-based broadband and the selective generation of orbital angular momentum (OAM carrying vector beams, N-fold OAM multicasting using a V-shaped antenna array, a metasurface on conventional optical fiber facet for linearly-polarized mode (LP11 generation, graphene split-ring metasurface-assisted terahertz coherent perfect absorption, OAM beam generation using a nanophotonic dielectric metasurface array, as well as Bessel beam generation and OAM multicasting using a dielectric metasurface array. It is believed that metasurface-based nanophotonic devices are one of the devices with the most potential applied in various fields, such as beam steering, spatial light modulator, nanoscale

  13. Super Dielectric Materials.

    Science.gov (United States)

    Fromille, Samuel; Phillips, Jonathan

    2014-12-22

    Evidence is provided here that a class of materials with dielectric constants greater than 10⁵ at low frequency (dielectric materials (SDM), can be generated readily from common, inexpensive materials. Specifically it is demonstrated that high surface area alumina powders, loaded to the incipient wetness point with a solution of boric acid dissolved in water, have dielectric constants, near 0 Hz, greater than 4 × 10⁸ in all cases, a remarkable increase over the best dielectric constants previously measured for energy storage capabilities, ca. 1 × 10⁴. It is postulated that any porous, electrically insulating material (e.g., high surface area powders of silica, titania, etc. ), filled with a liquid containing a high concentration of ionic species will potentially be an SDM. Capacitors created with the first generated SDM dielectrics (alumina with boric acid solution), herein called New Paradigm Super (NPS) capacitors display typical electrostatic capacitive behavior, such as increasing capacitance with decreasing thickness, and can be cycled, but are limited to a maximum effective operating voltage of about 0.8 V. A simple theory is presented: Water containing relatively high concentrations of dissolved ions saturates all, or virtually all, the pores (average diameter 500 Å) of the alumina. In an applied field the positive ionic species migrate to the cathode end, and the negative ions to the anode end of each drop. This creates giant dipoles with high charge, hence leading to high dielectric constant behavior. At about 0.8 V, water begins to break down, creating enough ionic species to "short" the individual water droplets. Potentially NPS capacitor stacks can surpass "supercapacitors" in volumetric energy density.

  14. Super Dielectric Materials

    Directory of Open Access Journals (Sweden)

    Samuel Fromille

    2014-12-01

    Full Text Available Evidence is provided here that a class of materials with dielectric constants greater than 105 at low frequency (<10−2 Hz, herein called super dielectric materials (SDM, can be generated readily from common, inexpensive materials. Specifically it is demonstrated that high surface area alumina powders, loaded to the incipient wetness point with a solution of boric acid dissolved in water, have dielectric constants, near 0 Hz, greater than 4 × 108 in all cases, a remarkable increase over the best dielectric constants previously measured for energy storage capabilities, ca. 1 × 104. It is postulated that any porous, electrically insulating material (e.g., high surface area powders of silica, titania, etc., filled with a liquid containing a high concentration of ionic species will potentially be an SDM. Capacitors created with the first generated SDM dielectrics (alumina with boric acid solution, herein called New Paradigm Super (NPS capacitors display typical electrostatic capacitive behavior, such as increasing capacitance with decreasing thickness, and can be cycled, but are limited to a maximum effective operating voltage of about 0.8 V. A simple theory is presented: Water containing relatively high concentrations of dissolved ions saturates all, or virtually all, the pores (average diameter 500 Å of the alumina. In an applied field the positive ionic species migrate to the cathode end, and the negative ions to the anode end of each drop. This creates giant dipoles with high charge, hence leading to high dielectric constant behavior. At about 0.8 V, water begins to break down, creating enough ionic species to “short” the individual water droplets. Potentially NPS capacitor stacks can surpass “supercapacitors” in volumetric energy density.

  15. Investigations of inorganic and hybrid inorganic-organic nanostructures

    Science.gov (United States)

    Kam, Kinson Chihang

    This thesis focuses on the exploratory synthesis and characterization of inorganic and hybrid inorganic-organic nanomaterials. In particular, nanostructures of semiconducting nitrides and oxides, and hybrid systems of nanowire-polymer composites and framework materials, are investigated. These materials are characterized by a variety of techniques for structure, composition, morphology, surface area, optical properties, and electrical properties. In the study of inorganic nanomaterials, gallium nitride (GaN), indium oxide (In2O3), and vanadium dioxide (VO2) nanostructures were synthesized using different strategies and their physical properties were examined. GaN nanostructures were obtained from various synthetic routes. Solid-state ammonolysis of metastable gamma-Ga2O 3 nanoparticles was found to be particularly successful; they achieved high surface areas and photoluminescent study showed a blue shift in emission as a result of surface and size defects. Similarly, In2O3 nanostructures were obtained by carbon-assisted solid-state syntheses. The sub-oxidic species, which are generated via a self-catalyzed vapor-liquid-solid mechanism, resulted in 1D nanostructures including nanowires, nanotrees, and nanobouquets upon oxidation. On the other hand, hydrothermal methods were used to obtain VO2 nanorods. After post-thermal treatment, infrared spectroscopy demonstrated that these nanorods exhibit a thermochromic transition with temperature that is higher by ˜10°C compared to the parent material. The thermochromic behavior indicated a semiconductor-to-metal transition associated with a structural transformation from monoclinic to rutile. The hybrid systems, on the other hand, enabled their properties to be tunable. In nanowire-polymer composites, zinc oxide (ZnO) and silver (Ag) nanowires were synthesized and incorporated into polyaniline (PANI) and polypyrrole (PPy) via in-situ and ex-situ polymerization method. The electrical properties of these composites are

  16. Thermally switchable dielectrics

    Science.gov (United States)

    Dirk, Shawn M.; Johnson, Ross S.

    2013-04-30

    Precursor polymers to conjugated polymers, such as poly(phenylene vinylene), poly(poly(thiophene vinylene), poly(aniline vinylene), and poly(pyrrole vinylene), can be used as thermally switchable capacitor dielectrics that fail at a specific temperature due to the non-conjugated precursor polymer irreversibly switching from an insulator to the conjugated polymer, which serves as a bleed resistor. The precursor polymer is a good dielectric until it reaches a specific temperature determined by the stability of the leaving groups. Conjugation of the polymer backbone at high temperature effectively disables the capacitor, providing a `built-in` safety mechanism for electronic devices.

  17. On dielectric breakdown statistics

    International Nuclear Information System (INIS)

    Tuncer, Enis; James, D Randy; Sauers, Isidor; Ellis, Alvin R; Pace, Marshall O

    2006-01-01

    In this paper, we investigate the dielectric breakdown data of some insulating materials and focus on the applicability of the two- and three-parameter Weibull distributions. A new distribution function is also proposed. In order to assess the model distribution's trustworthiness, we employ the Monte Carlo technique and, randomly selecting data-subsets from the whole dielectric breakdown data, determine whether the selected probability functions accurately describe the breakdown data. The utility and strength of the proposed expression are illustrated distinctly by the numerical procedure. The proposed expression is shown to be a valuable alternative to the Weibull ones

  18. Dielectric barrier discharges applied for soft ionization and their mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, Sebastian; Klute, Felix David; Schütz, Alexander; Franzke, Joachim, E-mail: joachim.franzke@isas.de

    2017-01-25

    Dielectric barrier discharges are used for analytical applications as dissociative source for optical emission spectrometry and for ambient-ionization techniques. In the range of ambient-ionization techniques it has attracted much attention in fields like food safety, biological analysis, mass spectrometry for reaction monitoring and imaging forensic identification. In this review some examples are given for the application as desorption/ionization source as well as for the sole application as ionization source with different sample introductions. It will be shown that the detection might depend on the certain distance of the plasma in reference to the sample or the kind of discharge which might be produced by different shapes of the applied high voltage. Some attempts of characterization are presented. A more detailed characterization of the dielectric barrier discharge realized with two ring electrodes, each separately covered with a dielectric layer, is described. - Highlights: • Dielectric barrier discharge applied as desorption/ionization source. • Dielectric barrier discharge applied solely as ionization source. • Different geometries in order to maintain soft ionization. • Characterization of the LTP probe. • Dielectric barrier discharges with two dielectric barriers (ring-ring shape).

  19. Study made of dielectric properties of promising materials for cryogenic capacitors

    Science.gov (United States)

    Mathes, K. N.; Minnich, S. H.

    1967-01-01

    Experimental investigations were conducted to determine dielectric properties of promising materials for cryogenic capacitors to be used in energy storage and pulse applications. The three classes of materials investigated were inorganic bonded ferroelectric materials, anodic coatings on metal foils, and polar low temperature liquids.

  20. Inorganic Constituents in Coal

    Directory of Open Access Journals (Sweden)

    Rađenović A.

    2006-02-01

    Full Text Available Coal contains not only organic matter but also small amounts of inorganic constituents. More thanone hundred different minerals and virtually every element in the periodic table have been foundin coal. Commonly found group minerals in coal are: major (quartz, pyrite, clays and carbonates,minor, and trace minerals. Coal includes a lot of elements of low mass fraction of the orderof w=0.01 or 0.001 %. They are trace elements connected with organic matter or minerals comprisedin coal. The fractions of trace elements usually decrease when the rank of coal increases.Fractions of the inorganic elements are different, depending on the coal bed and basin. A varietyof analytical methods and techniques can be used to determine the mass fractions, mode ofoccurrence, and distribution of organic constituents in coal. There are many different instrumentalmethods for analysis of coal and coal products but atomic absorption spectroscopy – AAS is theone most commonly used. Fraction and mode of occurrence are one of the main factors that haveinfluence on transformation and separation of inorganic constituents during coal conversion.Coal, as an important world energy source and component for non-fuels usage, will be continuouslyand widely used in the future due to its relatively abundant reserves. However, there is aconflict between the requirements for increased use of coal on the one hand and less pollution onthe other. It’s known that the environmental impacts, due to either coal mining or coal usage, canbe: air, water and land pollution. Although, minor components, inorganic constituents can exert asignificant influence on the economic value, utilization, and environmental impact of the coal.

  1. Inorganic Analytical Chemistry

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    The book is a treatise on inorganic analytical reactions in aqueous solution. It covers about half of the elements in the periodic table, i.e. the most important ones : H, Li, B, C, N, O, Na, Mg, Al, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, Mo, Ag, Cd, Sn, Sb, I, Ba, W,...

  2. Optics of Nanofibers

    DEFF Research Database (Denmark)

    Bordo, Vladimir

    During the last decade, fabrication and investigation of submicron-sized optical fibers have been received growing attention. Such nanofibers or nanowires can be grown from both inorganic and organic semiconductor materials being arranged in mutually parallel nanoaggregates. Also, selected...

  3. Broadband dielectric spectroscopy of oxidized porous silicon

    International Nuclear Information System (INIS)

    Axelrod, Ekaterina; Urbach, Benayahu; Sa'ar, Amir; Feldman, Yuri

    2006-01-01

    Dielectric measurements accompanied by infrared absorption and photoluminescence (PL) spectroscopy were used to investigate the electrical and optical properties of oxidized porous silicon (PS). As opposed to non-oxidized PS, only high temperature relaxation processes could be resolved for oxidized PS. Two relaxation processes have been observed. The first process is related to dc-conductivity that dominates at high temperatures and low frequencies. After subtraction of dc-conductivity we could analyse a second high-temperature relaxation process that is related to interface polarization induced by charge carriers trapped at the host matrix-pore interfaces. We found that, while the main effect of the oxidation on the PL appears to be a size reduction in the silicon nanocrystals that gives rise to a blue shift of the PL spectrum, its main contribution to the dielectric properties turns out to be blocking of transport channels in the host tissue and activation of hopping conductivity between silicon nanocrystals

  4. Broadband dielectric spectroscopy of oxidized porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Axelrod, Ekaterina [Department of Applied Physics, Hebrew University of Jerusalem, Jerusalem, 91904 (Israel); Urbach, Benayahu [Racah Institute of Physics and the Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904 (Israel); Sa' ar, Amir [Racah Institute of Physics and the Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904 (Israel); Feldman, Yuri [Department of Applied Physics, Hebrew University of Jerusalem, Jerusalem, 91904 (Israel)

    2006-04-07

    Dielectric measurements accompanied by infrared absorption and photoluminescence (PL) spectroscopy were used to investigate the electrical and optical properties of oxidized porous silicon (PS). As opposed to non-oxidized PS, only high temperature relaxation processes could be resolved for oxidized PS. Two relaxation processes have been observed. The first process is related to dc-conductivity that dominates at high temperatures and low frequencies. After subtraction of dc-conductivity we could analyse a second high-temperature relaxation process that is related to interface polarization induced by charge carriers trapped at the host matrix-pore interfaces. We found that, while the main effect of the oxidation on the PL appears to be a size reduction in the silicon nanocrystals that gives rise to a blue shift of the PL spectrum, its main contribution to the dielectric properties turns out to be blocking of transport channels in the host tissue and activation of hopping conductivity between silicon nanocrystals.

  5. Enhanced dielectric-wall linear accelerator

    Science.gov (United States)

    Sampayan, Stephen E.; Caporaso, George J.; Kirbie, Hugh C.

    1998-01-01

    A dielectric-wall linear accelerator is enhanced by a high-voltage, fast e-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

  6. Electromagnetic spin–orbit interaction and giant spin-Hall effect in dielectric particle clusters

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yineng [Department of Physics, Beijing Normal University, Beijing 100875 (China); Zhang, Xiangdong, E-mail: zhangxd@bit.edu.cn [School of Physics and Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, 100081, Beijing (China)

    2013-12-09

    We report a phenomenon that electromagnetic spin–orbit interactions can be tailored by dielectric nanoparticles, and self-similar giant spin-Hall effect has been observed in the dielectric particle cluster. The near-field phase singularities and phase vorticity in the longitudinal component of scattered field can also be controlled by such a dielectric structure. The origin of phenomena is believed to be due to the collective resonance excitation in the dielectric particle cluster. It is expected to find applications in optics information processing and designing new nanophotonic devices.

  7. The apparent effect of sample surface damage on the dielectric parameters of GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, J.A.A. [Physics Department, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa)], E-mail: Japie.Engelbrecht@nmmu.ac.za; Hashe, N.G. [Physics Department, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Hillie, K.T. [CSIR-NML Laboratory, P.O. Box 395, Pretoria 0001 (South Africa); Claassens, C.H. [Physics Department, University of the Free State, Bloemfontein 9300 (South Africa)

    2007-12-15

    The dielectric and optical parameters determined by infrared reflectance spectroscopy and computer simulation of a set of GaAs substrates of various surface topologies are reported. The influence of surface damage on the parameters is noted.

  8. The apparent effect of sample surface damage on the dielectric parameters of GaAs

    International Nuclear Information System (INIS)

    Engelbrecht, J.A.A.; Hashe, N.G.; Hillie, K.T.; Claassens, C.H.

    2007-01-01

    The dielectric and optical parameters determined by infrared reflectance spectroscopy and computer simulation of a set of GaAs substrates of various surface topologies are reported. The influence of surface damage on the parameters is noted

  9. Multiwavelength optical scatterometry of dielectric gratings

    KAUST Repository

    Yashina, Nataliya P.

    2012-08-01

    Modern scatterometry problems arising in the lithography production of periodic gratings are in the focus of the work. The performance capabilities of a novel theoretical and numerical modeling oriented to these problems are considered. The approach is based on rigorous solutions of 2-D initial boundary value problems of the gratings theory. The quintessence and advantage of the method is the possibility to perform an efficient analysis simultaneously and interactively both for steady state and transient processes of the resonant scattering of electromagnetic waves by the infinite and compact periodic structures. © 2012 IEEE.

  10. Synthesis, spectral, thermal, optical dispersion and dielectric ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... ... fast atom bombardment-mass spectrometry, thermogravimetric/ differential thermal analysis, and ... In UV spectrum, the transmittance increases followed by a sharp decrease at wavelength 700–750 nm within visible range.

  11. Synthesis, spectral, thermal, optical dispersion and dielectric ...

    Indian Academy of Sciences (India)

    of nanocrystalline dimer complex (PEPyr–diCd) thin films as novel organic semiconductor .... iments were obtained by diethyl ether diffusion to a solution in CH2Cl2. Pale brown ...... A F 2004 Phosphorus Sulfur Silicon Relat. Elem. 179 1251.

  12. Multiwavelength optical scatterometry of dielectric gratings

    KAUST Repository

    Yashina, Nataliya P.; Melezhik, Petr N.; Sirenko, Kostyantyn; Granet, Gerard

    2012-01-01

    is based on rigorous solutions of 2-D initial boundary value problems of the gratings theory. The quintessence and advantage of the method is the possibility to perform an efficient analysis simultaneously and interactively both for steady state

  13. Center for dielectric studies

    Science.gov (United States)

    Cross, L. E.; Newnham, R. E.; Biggers, J. V.

    1984-05-01

    This report focuses upon the parts of the Center program which have drawn most extensively upon Navy funds. In the basic study of polarization processes in high K dielectrics, major progress has been made in understanding the mechanisms in relaxor ferroelectric in the perovskite structure families. A new effort is also being mounted to obtain more precise evaluation of the internal stress effects in fine grained barium titanate. Related to reliability, studies of the effects of induced macro-defects are described, and preparation for the evaluation of space charge by internal potential distribution measurements discussed. To develop new processing methods for very thin dielectric layers, a new type of single barrier layer multilayer is discussed, and work on the thermal evaporation of oriented crystalline antimony sulphur iodide describe.

  14. Optical properties of solids

    CERN Document Server

    Wooten, Frederick

    1972-01-01

    Optical Properties of Solids covers the important concepts of intrinsic optical properties and photoelectric emission. The book starts by providing an introduction to the fundamental optical spectra of solids. The text then discusses Maxwell's equations and the dielectric function; absorption and dispersion; and the theory of free-electron metals. The quantum mechanical theory of direct and indirect transitions between bands; the applications of dispersion relations; and the derivation of an expression for the dielectric function in the self-consistent field approximation are also encompassed.

  15. Inorganic chemistry and medicine

    International Nuclear Information System (INIS)

    Sadler, P.J.; Guo, Z.

    1999-01-01

    Inorganic chemistry is beginning to have a major impact on medicine. Not only does it offer the prospect of the discovery of truly novel drugs and diagnostic agents, but it promises to make a major contribution to our understanding of the mechanism of action of organic drugs too. Most of this article is concerned with recent developments in medicinal coordination chemistry. The role of metal organic compounds of platinum, titanium, ruthenium, gallium, bismuth, gold, gadolinium, technetium, silver, cobalt in the treatment or diagnosis of common diseases are briefly are examined

  16. Dielectric properties of polyethylene

    International Nuclear Information System (INIS)

    Darwish, S.; Riad, A.S.; El-Shabasy, M.

    2005-01-01

    The temperature dependence of dielectric properties in polyethylene was measured in the frequency range from 10 to 105 Hz. The frequency dependence of the complex impedance in the complex plane could be fitted by semicircles. The system could be represented by an equivalent circuit of a bulk resistance in series with parallel surface resistance-capacitance combination. The relaxation time, has been evaluated from experimental results. Results reveal that the temperature dependence, is a thermally activated process

  17. Dielectric Wakefield Researches

    International Nuclear Information System (INIS)

    Kiselev, V.A.; Linnik, A.F.; Onishchenko, N.I.; Uskov, V.V.; Marshall, T.C.

    2006-01-01

    Excitation of wakefield in cylindrical dielectric waveguide/resonator by a sequence of relativistic electron bunches was investigated using an electron linac 'Almaz-2' (4.5 MeV, 6·10 3 bunches of duration 60 ps and charge 0.32 nC each). Energy spectrum of electrons, radial topography and longitudinal distribution of wakefield, and total energy of excited wakefield were measured by means of magnetic analyzer, high frequency probe, and a sensitive calorimeter

  18. Dielectric lattice gauge theory

    International Nuclear Information System (INIS)

    Mack, G.

    1983-06-01

    Dielectric lattice gauge theory models are introduced. They involve variables PHI(b)epsilong that are attached to the links b = (x+esub(μ),x) of the lattice and take their values in the linear space g which consists of real linear combinations of matrices in the gauge group G. The polar decomposition PHI(b)=U(b)osub(μ)(x) specifies an ordinary lattice gauge field U(b) and a kind of dielectric field epsilonsub(ij)proportionalosub(i)osub(j)sup(*)deltasub(ij). A gauge invariant positive semidefinite kinetic term for the PHI-field is found, and it is shown how to incorporate Wilson fermions in a way which preserves Osterwalder Schrader positivity. Theories with G = SU(2) and without matter fields are studied in some detail. It is proved that confinement holds, in the sense that Wilson loop expectation values show an area law decay, if the Euclidean action has certain qualitative features which imply that PHI = 0 (i.e. dielectric field identical 0) is the unique maximum of the action. (orig.)

  19. Dielectric lattice gauge theory

    International Nuclear Information System (INIS)

    Mack, G.

    1984-01-01

    Dielectric lattice gauge theory models are introduced. They involve variables PHI(b)element ofG that are attached to the links b = (x+esub(μ), x) of the lattice and take their values in the linear space G which consists of real linear combinations of matrices in the gauge group G. The polar decomposition PHI(b)=U(b)sigmasub(μ)(x) specifies an ordinary lattice gauge field U(b) and a kind of dielectric field epsilonsub(ij)proportional sigmasub(i)sigmasub(j)sup(*)deltasub(ij). A gauge invariant positive semidefinite kinetic term for the PHI-field is found, and it is shown how to incorporate Wilson fermions in a way which preserves Osterwalder-Schrader positivity. Theories with G = SU(2) and without matter fields are studied in some detail. It is proved that confinement holds, in the sense that Wilson-loop expectation values show an area law decay, if the euclidean action has certain qualitative features which imply that PHI=0 (i.e. dielectric field identical 0) is the unique maximum of the action. (orig.)

  20. Extraction and dielectric properties of curcuminoid films grown on Si substrate for high-k dielectric applications

    International Nuclear Information System (INIS)

    Dakhel, A.A.; Jasim, Khalil E.; Cassidy, S.; Henari, F.Z.

    2013-01-01

    Highlights: • The unknown insulating properties of curcuminoid extract are systematically studied. • Optical study gives a bandgap of 3.15 eV and a refractive index of 1.92 at 505 nm. • Turmeric is a high-k environmental friendly material for use in microelectronics. • Curcuminoid extract can be used as insulator of MIS devices with ε ′ ∞ ≈54.2. -- Abstract: Curcuminoids were extracted from turmeric powder and evaporated in vacuum to prepare thin films on p-Si and glass substrates for dielectric and optical investigations. The optical absorption spectrum of the prepared amorphous film was not identical to that of the molecular one, which was identified by a strong wide absorption band in between ∼220 and 540 nm. The onset energy of the optical absorption of the film was calculated by using Hamberg et al. method. The dielectric properties of this material were systematically studied for future eco friendly applications in metal–insulator–semiconductor MIS field of applications. The complex dielectric properties were studied in the frequency range of 1–1000 kHz and was analysed in-terms of dielectric impedance Z * (ω) and modulus M * (ω). Generally, the curcuminoid complex can be considered as a high-k material and can be used in the environmental friendly production of microelectronic devices

  1. Extraction and dielectric properties of curcuminoid films grown on Si substrate for high-k dielectric applications

    Energy Technology Data Exchange (ETDEWEB)

    Dakhel, A.A.; Jasim, Khalil E. [Department of Physics, College of Science, University of Bahrain, P.O. Box 32038 (Bahrain); Cassidy, S. [Department of Basic Medical Sciences, Royal College of Surgeons in Ireland, Medical University of Bahrain, P.O. Box 15503 (Bahrain); Henari, F.Z., E-mail: fzhenari@rcsi-mub.com [Department of Basic Medical Sciences, Royal College of Surgeons in Ireland, Medical University of Bahrain, P.O. Box 15503 (Bahrain)

    2013-09-20

    Highlights: • The unknown insulating properties of curcuminoid extract are systematically studied. • Optical study gives a bandgap of 3.15 eV and a refractive index of 1.92 at 505 nm. • Turmeric is a high-k environmental friendly material for use in microelectronics. • Curcuminoid extract can be used as insulator of MIS devices with ε{sup ′}{sub ∞}≈54.2. -- Abstract: Curcuminoids were extracted from turmeric powder and evaporated in vacuum to prepare thin films on p-Si and glass substrates for dielectric and optical investigations. The optical absorption spectrum of the prepared amorphous film was not identical to that of the molecular one, which was identified by a strong wide absorption band in between ∼220 and 540 nm. The onset energy of the optical absorption of the film was calculated by using Hamberg et al. method. The dielectric properties of this material were systematically studied for future eco friendly applications in metal–insulator–semiconductor MIS field of applications. The complex dielectric properties were studied in the frequency range of 1–1000 kHz and was analysed in-terms of dielectric impedance Z{sup *}(ω) and modulus M{sup *}(ω). Generally, the curcuminoid complex can be considered as a high-k material and can be used in the environmental friendly production of microelectronic devices.

  2. A Switchable Molecular Dielectric with Two Sequential Reversible Phase Transitions: [(CH3)4P]4[Mn(SCN)6].

    Science.gov (United States)

    Li, Qiang; Shi, Ping-Ping; Ye, Qiong; Wang, Hui-Ting; Wu, De-Hong; Ye, Heng-Yun; Fu, Da-Wei; Zhang, Yi

    2015-11-16

    A new organic-inorganic hybrid switchable and tunable dielectric compound, [(CH3)4P]4[Mn(SCN)6] (1), exhibits three distinct dielectric states above room temperature and undergoes two reversible solid-state phase transitions, including a structural phase transition at 330 K and a ferroelastic phase transition with the Aizu notation of mmmF2/m at 352 K. The variable-temperature structural analyses disclose that the origin of the phase transitions and dielectric anomalies can be ascribed to the reorientation or motion of both the [(CH3)4P](+) cations and [Mn(SCN)6](4-) anions in solid-state crystals.

  3. Dielectric platforms for surface-enhanced spectroscopies (Conference Presentation)

    Science.gov (United States)

    Maier, Stefan A.

    2016-03-01

    Plasmonic nanostructures serve as the main backbone of surface enhanced sensing methodologies, yet the associated optical losses lead to localized heating as well as quenching of molecules, complicating their use for enhancement of fluorescent emission. Additionally, conventional plasmonic materials are limited to operation in the visible part of the spectrum. We will elucidate how nanostructures consisting of conventional and polar dielectrics can be employed as a highly promising alternative platform. Dielectric nanostructures can sustain scattering resonances due to both electric and magnetic Mie modes. We have recently predicted high enhanced local electromagnetic field hot spots in dielectric nanoantenna dimers, with the hallmark of spot sizes comparable to those achievable with plasmonic antennas, but with lower optical losses. Here, we will present first experimental evidence for both fluorescence and Raman enhancement in dielectric nanoantennas, including a direct determination of localized heating, and compare to conventional Au dimer antennas. The second part of the talk will focus on the mid-infrared regime of the electromagnetic spectrum, outlining possibilities for surface enhanced infrared absorption spectroscopy based on polar and hyperbolic dielectrics.

  4. Self assembled monolayers of octadecyltrichlorosilane for dielectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Vijay, E-mail: cirivijaypilani@gmail.com [Centre for Nanoscience and Engineering, Indian Institute of Science-Bangalore (India); Mechanical Engineering Department, Birla Institute of Technology and Science-Pilani (India); Puri, Paridhi; Nain, Shivani [Mechanical Engineering Department, Birla Institute of Technology and Science-Pilani (India); Bhat, K. N. [Centre for Nanoscience and Engineering, Indian Institute of Science-Bangalore (India); Sharma, N. N. [Mechanical Engineering Department, Birla Institute of Technology and Science-Pilani (India); School of Automobile, Mechanical & Mechatronics, Manipal University-Jaipur (India)

    2016-04-13

    Treatment of surfaces to change the interaction of fluids with them is a critical step in constructing useful microfluidics devices, especially those used in biological applications. Selective modification of inorganic materials such as Si, SiO{sub 2} and Si{sub 3}N{sub 4} is of great interest in research and technology. We evaluated the chemical formation of OTS self-assembled monolayers on silicon substrates with different dielectric materials. Our investigations were focused on surface modification of formerly used common dielectric materials SiO{sub 2}, Si{sub 3}N{sub 4} and a-poly. The improvement of wetting behaviour and quality of monolayer films were characterized using Atomic force microscope, Scanning electron microscope, Contact angle goniometer, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) monolayer deposited oxide surface.

  5. Thin film transistors for flexible electronics: Contacts, dielectrics and semiconductors

    KAUST Repository

    Quevedo-López, Manuel Angel Quevedo

    2011-06-01

    The development of low temperature, thin film transistor processes that have enabled flexible displays also present opportunities for flexible electronics and flexible integrated systems. Of particular interest are possible applications in flexible sensor systems for unattended ground sensors, smart medical bandages, electronic ID tags for geo-location, conformal antennas, radiation detectors, etc. In this paper, we review the impact of gate dielectrics, contacts and semiconductor materials on thin film transistors for flexible electronics applications. We present our recent results to fully integrate hybrid complementary metal oxide semiconductors comprising inorganic and organic-based materials. In particular, we demonstrate novel gate dielectric stacks and semiconducting materials. The impact of source and drain contacts on device performance is also discussed. Copyright © 2011 American Scientific Publishers.

  6. Thin film transistors for flexible electronics: Contacts, dielectrics and semiconductors

    KAUST Repository

    Quevedo-Ló pez, Manuel Angel Quevedo; Wondmagegn, Wudyalew T.; Alshareef, Husam N.; Ramí rez-Bon, Rafael; Gnade, Bruce E.

    2011-01-01

    The development of low temperature, thin film transistor processes that have enabled flexible displays also present opportunities for flexible electronics and flexible integrated systems. Of particular interest are possible applications in flexible sensor systems for unattended ground sensors, smart medical bandages, electronic ID tags for geo-location, conformal antennas, radiation detectors, etc. In this paper, we review the impact of gate dielectrics, contacts and semiconductor materials on thin film transistors for flexible electronics applications. We present our recent results to fully integrate hybrid complementary metal oxide semiconductors comprising inorganic and organic-based materials. In particular, we demonstrate novel gate dielectric stacks and semiconducting materials. The impact of source and drain contacts on device performance is also discussed. Copyright © 2011 American Scientific Publishers.

  7. Dielectric properties of lunar surface

    Science.gov (United States)

    Yushkova, O. V.; Kibardina, I. N.

    2017-03-01

    Measurements of the dielectric characteristics of lunar soil samples are analyzed in the context of dielectric theory. It has been shown that the real component of the dielectric permittivity and the loss tangent of rocks greatly depend on the frequency of the interacting electromagnetic field and the soil temperature. It follows from the analysis that one should take into account diurnal variations in the lunar surface temperature when interpreting the radar-sounding results, especially for the gigahertz radio range.

  8. Hydrothermal synthetic strategies of inorganic semiconducting nanostructures.

    Science.gov (United States)

    Shi, Weidong; Song, Shuyan; Zhang, Hongjie

    2013-07-07

    Because of their unique chemical and physical properties, inorganic semiconducting nanostructures have gradually played a pivotal role in a variety of research fields, including electronics, chemical reactivity, energy conversion, and optics. A major feature of these nanostructures is the quantum confinement effect, which strongly depends on their size, shape, crystal structure and polydispersity. Among all developed synthetic methods, the hydrothermal method based on a water system has attracted more and more attention because of its outstanding advantages, such as high yield, simple manipulation, easy control, uniform products, lower air pollution, low energy consumption and so on. Precise control over the hydrothermal synthetic conditions is a key to the success of the preparation of high-quality inorganic semiconducting nanostructures. In this review, only the representative hydrothermal synthetic strategies of inorganic semiconducting nanostructures are selected and discussed. We will introduce the four types of strategies based on exterior reaction system adjustment, namely organic additive- and template-free hydrothermal synthesis, organic additive-assisted hydrothermal synthesis, template-assisted hydrothermal synthesis and substrate-assisted hydrothermal synthesis. In addition, the two strategies based on exterior reaction environment adjustment, including microwave-assisted and magnetic field-assisted hydrothermal synthesis, will be also described. Finally, we conclude and give the future prospects of this research area.

  9. Optical cavity cooling of mechanical modes of a semiconductor nanomembrane

    DEFF Research Database (Denmark)

    Usami, Koji; Naesby, A.; Bagci, Tolga

    2012-01-01

    Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high-quality-factor and......Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high...

  10. Improved polymer nanocomposite dielectric breakdown performance through barium titanate to epoxy interface control

    Energy Technology Data Exchange (ETDEWEB)

    Siddabattuni, Sasidhar [Missouri University of Science and Technology (formerly the University of Missouri-Rolla), Chemistry Department, 400W. 11th Street, Rolla, MO 65409 (United States); Schuman, Thomas P., E-mail: tschuman@mst.edu [Missouri University of Science and Technology (formerly the University of Missouri-Rolla), Chemistry Department, 400W. 11th Street, Rolla, MO 65409 (United States); Dogan, Fatih [Missouri University of Science and Technology, Materials Science and Engineering Department, 1400N. Bishop Avenue, Rolla, MO 65409 (United States)

    2011-11-15

    Highlights: > A covalent filler-matrix interface improves the dielectric properties of a polymer-particle nanocomposite dielectric. > A covalent interface reduced the polymer free volume around the nanoparticles as assessed through T{sub g} measurements. > Composite T{sub g} was raised and breakdown strength improved for nanocomposites with a covalent polymer-particle interface. > A larger Maxwell-Wagner (MW) relaxation correlated with reduced breakdown strengths and energy storage densities. > The MW relaxation could be considered a dielectric defect regarding breakdown strength and energy storage density. - Abstract: A composite approach to dielectric design has the potential to provide improved permittivity as well as high breakdown strength and thus afford greater electrical energy storage density. Interfacial coupling is an effective approach to improve the polymer-particle composite dielectric film resistance to charge flow and dielectric breakdown. A bi-functional interfacial coupling agent added to the inorganic oxide particles' surface assists dispersion into the thermosetting epoxy polymer matrix and upon composite cure reacts covalently with the polymer matrix. The composite then retains the glass transition temperature of pure polymer, provides a reduced Maxwell-Wagner relaxation of the polymer-particle composite, and attains a reduced sensitivity to dielectric breakdown compared to particle epoxy composites that lack interfacial coupling between the composite filler and polymer matrix. Besides an improved permittivity, the breakdown strength and thus energy density of a covalent interface nanoparticle barium titanate in epoxy composite dielectric film, at a 5 vol.% particle concentration, was significantly improved compared to a pure polymer dielectric film. The interfacially bonded, dielectric composite film had a permittivity {approx}6.3 and at a 30 {mu}m thickness achieved a calculated energy density of 4.6 J/cm{sup 3}.

  11. Improved polymer nanocomposite dielectric breakdown performance through barium titanate to epoxy interface control

    International Nuclear Information System (INIS)

    Siddabattuni, Sasidhar; Schuman, Thomas P.; Dogan, Fatih

    2011-01-01

    Highlights: → A covalent filler-matrix interface improves the dielectric properties of a polymer-particle nanocomposite dielectric. → A covalent interface reduced the polymer free volume around the nanoparticles as assessed through T g measurements. → Composite T g was raised and breakdown strength improved for nanocomposites with a covalent polymer-particle interface. → A larger Maxwell-Wagner (MW) relaxation correlated with reduced breakdown strengths and energy storage densities. → The MW relaxation could be considered a dielectric defect regarding breakdown strength and energy storage density. - Abstract: A composite approach to dielectric design has the potential to provide improved permittivity as well as high breakdown strength and thus afford greater electrical energy storage density. Interfacial coupling is an effective approach to improve the polymer-particle composite dielectric film resistance to charge flow and dielectric breakdown. A bi-functional interfacial coupling agent added to the inorganic oxide particles' surface assists dispersion into the thermosetting epoxy polymer matrix and upon composite cure reacts covalently with the polymer matrix. The composite then retains the glass transition temperature of pure polymer, provides a reduced Maxwell-Wagner relaxation of the polymer-particle composite, and attains a reduced sensitivity to dielectric breakdown compared to particle epoxy composites that lack interfacial coupling between the composite filler and polymer matrix. Besides an improved permittivity, the breakdown strength and thus energy density of a covalent interface nanoparticle barium titanate in epoxy composite dielectric film, at a 5 vol.% particle concentration, was significantly improved compared to a pure polymer dielectric film. The interfacially bonded, dielectric composite film had a permittivity ∼6.3 and at a 30 μm thickness achieved a calculated energy density of 4.6 J/cm 3 .

  12. Polystyrene-poly(vinylphenol) copolymers as compatibilzers for organic-inorganic composites

    International Nuclear Information System (INIS)

    Landry, C.J.T.; Coltrain, B.K.; Teegarden, D.M.

    1996-01-01

    Random, graft, and block copolymers of polystyrene (PS) and poly(4-vinylphenol) (PVPh), and PVPh homopolymer are shown to act as compatibilizers for incompatible organic-inorganic composite materials. The VPh component reacts, or interacts strongly with the polymerizing inorganic (titanium or zirconium) alkoxide. The organic components studied were PS, poly(vinyl methyl ether), and poly(styrene-co-acrylonitrile). The use of such compatibilizers provides a means of combining in situ polymerized inorganic oxides and hydrophobic polymers. This is seen as a reduction in the size of the dispersed inorganic phase and results in improved optical and mechanical properties

  13. Electronic, mechanical and dielectric properties of silicane under tensile strain

    International Nuclear Information System (INIS)

    Jamdagni, Pooja; Sharma, Munish; Ahluwalia, P. K.; Kumar, Ashok; Thakur, Anil

    2015-01-01

    The electronic, mechanical and dielectric properties of fully hydrogenated silicene i.e. silicane in stable configuration are studied by means of density functional theory based calculations. The band gap of silicane monolayer can be flexibly reduced to zero when subjected to bi-axial tensile strain, leading to semi-conducting to metallic transition, whereas the static dielectric constant for in-plane polarization increases monotonically with increasing strain. Also the EEL function show the red shift in resonance peak with tensile strain. Our results offer useful insight for the application of silicane monolayer in nano-optical and electronics devices

  14. Inorganic Halogen Oxidizer Research

    Science.gov (United States)

    1979-02-16

    Inorganic Chemistry. Vol. 14. No. 9. 1975 Karl 0. Christ¢ (21) L. J. Basile . P. LaBonvillk. J. R. Ferraro, and J. M. Williams. J. Claim. (38) K. 0. Chriae. E... basils of a nonplanar structure of symmetry CI, are revised for six fundamental frequencies. Imalredetle either the 1:2 adduct N 2F4.2SbF5 or the 1:3...8217 in mT are 7 2.1 for B, facility. We aba thank L. K. White and R. L. Belford 111.0 for C, 55.0 for N, and 17100 for F, and the atomic aniso- trop’c

  15. Modern Trends in Inorganic Chemistry

    Indian Academy of Sciences (India)

    Administrator

    The series of symposia on 'Modern Trends in Inorganic Chemistry' (MTIC), which began in 1985 at the Indian Association for Cultivation of Science, Calcutta has evolved into a forum for the Inorganic Chemistry fraternity of the country to meet every two years and discuss the current status and future projections of research in.

  16. Stimulated light emission in a dielectrically disordered composite porous matrix

    Science.gov (United States)

    Gross, E.; Künzner, N.; Diener, J.; Fujii, Minoru; Timoshenko, V. Yu.; Kovalev, D.

    2005-06-01

    We report on a medium exhibiting extremely efficient light scattering properties: a liquid network formed in a porous matrix. Liquid fragments confined in the solid matrix result in a random fluctuation of the dielectric function and act as scattering objects for photons. The optical scattering efficiency is defined by the filling factor of the liquid in the pores and its dielectric constant. The spectral dependence of the scattering length of photons indicates that the phenomenon is governed by a Mie-type scattering mechanism. The degree of the dielectric disorder of the medium, i.e. the level of opacity is tunable by the ambient vapor pressure of the dielectric substance. In the strongest scattering regime the scattering length of photons is found to be in the micrometer range. By incorporation of dye molecules in the voids of the porous layer a system exhibiting optical gain is realized. In the multiple scattering regime the optical path of diffusively propagating photons is enhanced and light amplification through stimulated emission occurs: a strong intensity enhancement of the dye emission accompanied by significant spectral narrowing is observed above the excitation threshold for a layer being in the opalescence state.

  17. Dielectric Properties Of Nanoferrites

    International Nuclear Information System (INIS)

    Jankov, Stevan B.; Cvejic, Zeljka N.; Rakic, Srdjan; Srdic, Vladimir

    2007-01-01

    Dielectric properties: permittivity, loss factor, tan delta and ionic conductivity of nanostructured ferrites have been measured. Samples used were nickel, zinc and yttrium doped ferrites mixed in various ratios. The synthesis has been performed using precipitation method and obtained powders were pressed in pellets under varying pressure. X-ray diffractography approach for the refinement of structure and microstructural analysis has been performed. All parameters have been measured in 1 Hz to 100 kHz frequency range and 30 deg. C to 80 deg. C temperature range. Significant improvements in permittivity, loss factor and ionic conductivity comparing to bulk samples have been observed

  18. Dielectric materials and electrostatics

    CERN Document Server

    Gallot-Lavalle, Olivier

    2013-01-01

    An introduction to the physics of electrical insulation, this book presents the physical foundations of this discipline and the resulting applications. It is structured in two parts. The first part presents a mathematical and intuitive approach to dielectrics; various concepts, including polarization, induction, forces and losses are discussed. The second part provides readers with the keys to understanding the physics of solid, liquid and gas insulation. It comprises a phenomenological description of discharges in gas and its resulting applications. Finally, the main electrical properties

  19. An omnidirectional retroreflector based on the transmutation of dielectric singularities.

    Science.gov (United States)

    Ma, Yun Gui; Ong, C K; Tyc, Tomás; Leonhardt, Ulf

    2009-08-01

    Transformation optics is a concept used in some metamaterials to guide light on a predetermined path. In this approach, the materials implement coordinate transformations on electromagnetic waves to create the illusion that the waves are propagating through a virtual space. Transforming space by appropriately designed materials makes devices possible that have been deemed impossible. In particular, transformation optics has led to the demonstration of invisibility cloaking for microwaves, surface plasmons and infrared light. Here, on the basis of transformation optics, we implement a microwave device that would normally require a dielectric singularity, an infinity in the refractive index. To fabricate such a device, we transmute a dielectric singularity in virtual space into a mere topological defect in a real metamaterial. In particular, we demonstrate an omnidirectional retroreflector, a device for faithfully reflecting images and for creating high visibility from all directions. Our method is robust, potentially broadband and could also be applied to visible light using similar techniques.

  20. Bistable scattering in graphene-coated dielectric nanowires.

    Science.gov (United States)

    Li, Rujiang; Wang, Huaping; Zheng, Bin; Dehdashti, Shahram; Li, Erping; Chen, Hongsheng

    2017-06-22

    In nonlinear plasmonics, the switching threshold of optical bistability is limited by the weak nonlinear responses from the conventional Kerr dielectric media. Considering the giant nonlinear susceptibility of graphene, here we develop a nonlinear scattering model under the mean field approximation and study the bistable scattering in graphene-coated dielectric nanowires based on the semi-analytical solutions. We find that the switching intensities of bistable scattering can be smaller than 1 MW cm -2 at the working frequency. To further decrease the switching intensities, we show that the most important factor that restricts the bistable scattering is the relaxation time of graphene. Our work not only reveals some general characteristics of graphene-based bistable scattering, but also provides a guidance to further applications of optical bistability in the high speed all-optical signal processing.

  1. Discharge ignition near a dielectric

    NARCIS (Netherlands)

    Sobota, A.; Veldhuizen, van E.M.; Stoffels, W.W.

    2008-01-01

    Electrical breakdown in noble gas near a dielectric is an important issue in lighting industry. In order to investigate the influence of the dielectric on the ignition process, we perform measurements in argon, with pressure varying from 0.1 to 1 bar, using a pin–pin electrode geometry. Here, we

  2. Concepts of classical optics

    CERN Document Server

    Strong, John

    1958-01-01

    An intermediate course in optics, this volume explores both experimental and theoretical concepts, offering practical knowledge of geometrical optics that will enhance students' comprehension of any relevant applied science. Its exposition of the concepts of classical optics is presented with a minimum of mathematical detail but presumes some knowledge of calculus, vectors, and complex numbers.Subjects include light as wave motion; superposition of wave motions; electromagnetic waves; interaction of light and matter; velocities and scattering of light; polarized light and dielectric boundarie

  3. Dielectric Screening Meets Optimally Tuned Density Functionals.

    Science.gov (United States)

    Kronik, Leeor; Kümmel, Stephan

    2018-04-17

    A short overview of recent attempts at merging two independently developed methods is presented. These are the optimal tuning of a range-separated hybrid (OT-RSH) functional, developed to provide an accurate first-principles description of the electronic structure and optical properties of gas-phase molecules, and the polarizable continuum model (PCM), developed to provide an approximate but computationally tractable description of a solvent in terms of an effective dielectric medium. After a brief overview of the OT-RSH approach, its combination with the PCM as a potentially accurate yet low-cost approach to the study of molecular assemblies and solids, particularly in the context of photocatalysis and photovoltaics, is discussed. First, solvated molecules are considered, with an emphasis on the challenge of balancing eigenvalue and total energy trends. Then, it is shown that the same merging of methods can also be used to study the electronic and optical properties of molecular solids, with a similar discussion of the pros and cons. Tuning of the effective scalar dielectric constant as one recent approach that mitigates some of the difficulties in merging the two approaches is considered. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Inorganic Fullerene-Like Nanoparticles and Inorganic Nanotubes

    Directory of Open Access Journals (Sweden)

    Reshef Tenne

    2014-11-01

    Full Text Available Fullerene-like nanoparticles (inorganic fullerenes; IF and nanotubes of inorganic layered compounds (inorganic nanotubes; INT combine low dimensionality and nanosize, enhancing the performance of corresponding bulk counterparts in their already known applications, as well as opening new fields of their own [1]. This issue gathers articles from the diverse area of materials science and is devoted to fullerene-like nanoparticles and nanotubes of layered sulfides and boron nitride and collects the most current results obtained at the interface between fundamental research and engineering.[...

  5. Generalized dielectric permittivity tensor

    International Nuclear Information System (INIS)

    Borzdov, G.N.; Barkovskii, L.M.; Fedorov, F.I.

    1986-01-01

    The authors deal with the question of what is to be done with the formalism of the electrodynamics of dispersive media based on the introduction of dielectric-permittivity tensors for purely harmonic fields when Voigt waves and waves of more general form exist. An attempt is made to broaden and generalize the formalism to take into account dispersion of waves of the given type. In dispersive media, the polarization, magnetization, and conduction current-density vectors of point and time are determined by the values of the electromagnetic field vectors in the vicinity of this point (spatial dispersion) in the preceding instants of time (time dispersion). The dielectric-permittivity tensor and other tensors of electrodynamic parameters of the medium are introduced in terms of a set of evolution operators and not the set of harmonic function. It is noted that a magnetic-permeability tensor and an elastic-modulus tensor may be introduced for an acoustic field in dispersive anisotropic media with coupling equations of general form

  6. Dielectric Actuation of Polymers

    Science.gov (United States)

    Niu, Xiaofan

    Dielectric polymers are widely used in a plurality of applications, such as electrical insulation, dielectric capacitors, and electromechanical actuators. Dielectric polymers with large strain deformations under an electric field are named dielectric elastomers (DE), because of their relative low modulus, high elongation at break, and outstanding resilience. Dielectric elastomer actuators (DEA) are superior to traditional transducers as a muscle-like technology: large strains, high energy densities, high coupling efficiency, quiet operation, and light weight. One focus of this dissertation is on the design of DE materials with high performance and easy processing. UV radiation curing of reactive species is studied as a generic synthesis methodology to provide a platform for material scientists to customize their own DE materials. Oligomers/monomers, crosslinkers, and other additives are mixed and cured at appropriate ratios to control the stress-strain response, suppress electromechanical instability of the resulting polymers, and provide stable actuation strains larger than 100% and energy densities higher than 1 J/g. The processing is largely simplified in the new material system by removal of the prestretching step. Multilayer stack actuators with 11% linear strain are demonstrated in a procedure fully compatible with industrial production. A multifunctional DE derivative material, bistable electroactive polymer (BSEP), is invented enabling repeatable rigid-to-rigid deformation without bulky external structures. Bistable actuation allows the polymer actuator to have two distinct states that can support external load without device failure. Plasticizers are used to lower the glass transition temperature to 45 °C. Interpenetrating polymer network structure is established inside the BSEP to suppress electromechanical instability, providing a breakdown field of 194 MV/m and a stable bistable strain as large as 228% with a 97% strain fixity. The application of BSEP

  7. Radioresistance of inorganic glasses

    International Nuclear Information System (INIS)

    Vorob'ev, A.A.; Zavadovskaya, E.K.; Fedorov, B.V.; Starodubtsev, V.A.

    1977-01-01

    Regularities are considered in the variation of properties of glass due to irradiations. On the basis of previous theoretical statements and experimental investigations, it is inferred that the irradiation resistance of glasses of the same type, synthesis conditions, content of impurities and amount of imperfections, is a function of the ''element-oxygen'' bond energy. The irradiation resistance depends on the number and the nature of glass structure imperfections. The averaged level of bonding forces is indicative of the glass formation temperature; the imperfections in glasses are formed in structure elements whose amount predominates as compared to the others. Electric charges which accumulate on the crack surface tend to increase its size, thus lessening even further the electric strength of the dielectric. The greater the irradiation time, the greater the number of irradiation imperfections causing a drop in the electric strength of glass. When choosing a glass for service in a radiation field, it is necessary to select those of a highest temperature of glass formation and with a least amount of imperfections

  8. Silicone elastomers with superior softness and dielectric properties

    DEFF Research Database (Denmark)

    Yu, Liyun; Madsen, Frederikke Bahrt; Zakaria, Shamsul Bin

    Dielectric elastomers (DEs) change their shape and size under a high voltage or reversibly generate a high voltage when deformed. The obstacle of high driving voltages, however, limits the commercial viability of the technology at present. Driving voltage can be lowered by decreasing the Young......’s modulus and increasing the dielectric permittivity of silicone elastomers. One such prominent method of modifying the properties is by adding suitable additives. [1] The major drawbacks for adding solid fillers are agglomeration and increasing stiffness which is often accompanied by the decrease...... were determined by NMR and morphology structures were investigated by optical microscopy. The resulting elastomers were evaluated with respect to their dielectric permittivity, tear and tensile strengths, as well as electrical breakdown.The breakdown strength increased at low amounts of additives...

  9. Laser polarization dependent and magnetically control of group velocity in a dielectric medium doped with nanodiamond nitrogen vacancy centers

    Energy Technology Data Exchange (ETDEWEB)

    Asadpour, Seyyed Hossein; Rahimpour Soleimani, H., E-mail: Rahimpour@guilan.ac.ir

    2014-03-01

    In this paper, group velocity control of Gaussian beam in a dielectric medium doped with nanodiamond nitrogen vacancy (NV) centers under optical excitation is discussed. The shape of transmitted and reflected pulses from dielectric can be tuned by changing the intensity of magnetic field and polarization of the control beam. The effect of intensity of control beam on group velocity is also investigated.

  10. A hybrid organic-inorganic perovskite dataset

    Science.gov (United States)

    Kim, Chiho; Huan, Tran Doan; Krishnan, Sridevi; Ramprasad, Rampi

    2017-05-01

    Hybrid organic-inorganic perovskites (HOIPs) have been attracting a great deal of attention due to their versatility of electronic properties and fabrication methods. We prepare a dataset of 1,346 HOIPs, which features 16 organic cations, 3 group-IV cations and 4 halide anions. Using a combination of an atomic structure search method and density functional theory calculations, the optimized structures, the bandgap, the dielectric constant, and the relative energies of the HOIPs are uniformly prepared and validated by comparing with relevant experimental and/or theoretical data. We make the dataset available at Dryad Digital Repository, NoMaD Repository, and Khazana Repository (http://khazana.uconn.edu/), hoping that it could be useful for future data-mining efforts that can explore possible structure-property relationships and phenomenological models. Progressive extension of the dataset is expected as new organic cations become appropriate within the HOIP framework, and as additional properties are calculated for the new compounds found.

  11. Cancer risk from inorganics

    International Nuclear Information System (INIS)

    Swierenga, S.H.; Gilman, J.P.; McLean, J.R.

    1987-01-01

    Inorganic metals and minerals for which there is evidence of carcinogenicity are identified. The risk of cancer from contact with them in the work place, the general environment, and under conditions of clinical (medical) exposure is discussed. The evidence indicates that minerals and metals most often influence cancer development through their action as cocarcinogens. The relationship between the physical form of mineral fibers, smoking and carcinogenic risk is emphasized. Metals are categorized as established (As, Be, Cr, Ni), suspected (Cd, Pb) and possible carcinogens, based on the existing in vitro, animal experimental and human epidemiological data. Cancer risk and possible modes of action of elements in each class are discussed. Views on mechanisms that may be responsible for the carcinogenicity of metals are updated and analysed. Some specific examples of cancer risks associated with the clinical use of potentially carcinogenic metals and from radioactive pharmaceuticals used in therapy and diagnosis are presented. Questions are raised as to the effectiveness of conventional dosimetry in accurately measuring risk from radiopharmaceuticals. 302 references

  12. Inorganic chemistry of earliest sediments

    International Nuclear Information System (INIS)

    Ochiai, E.I.

    1983-01-01

    A number of inorganic elements are now known to be essential to organisms. Chemical evolutionary processes involving carbon, hydrogen, nitrogen and oxygen have been studied intensively and extensively, but the other essential elements have been rather neglected in the studies of chemical and biological evolution. This article attempts to assess the significance of inorganic chemistry in chemical and biological evolutionary processes on the earth. Emphasis is placed on the catalytic effects of inorganic elements and compounds, and also on possible studies on the earliest sediments, especially banded iron formation and stratabound copper from the inorganic point of view in the hope of shedding some light on the evolution of the environment and the biological effects on it. (orig./WL)

  13. Organic-Inorganic Perovskites: Structural Versatility for Functional Materials Design.

    Science.gov (United States)

    Saparov, Bayrammurad; Mitzi, David B

    2016-04-13

    Although known since the late 19th century, organic-inorganic perovskites have recently received extraordinary research community attention because of their unique physical properties, which make them promising candidates for application in photovoltaic (PV) and related optoelectronic devices. This review will explore beyond the current focus on three-dimensional (3-D) lead(II) halide perovskites, to highlight the great chemical flexibility and outstanding potential of the broader class of 3-D and lower dimensional organic-based perovskite family for electronic, optical, and energy-based applications as well as fundamental research. The concept of a multifunctional organic-inorganic hybrid, in which the organic and inorganic structural components provide intentional, unique, and hopefully synergistic features to the compound, represents an important contemporary target.

  14. Transparent bulk-size nanocomposites with high inorganic loading

    International Nuclear Information System (INIS)

    Chen, Shi; Gaume, Romain

    2015-01-01

    With relatively high nanoparticle loading in polymer matrices, hybrid nanocomposites made by colloidal dispersion routes suffer from severe inhomogeneous agglomeration, a phenomenon that deteriorates light transmission even when the refractive indices of the inorganic and organic phases are closely matched. The dispersion of particles in a matrix is of paramount importance to obtain composites of high optical quality. Here, we describe an innovative, yet straightforward method to fabricate monolithic transparent hybrid nanocomposites with very high particle loading and high refractive index mismatch tolerance between the inorganic and organic constituents. We demonstrate 77% transmission at 800 nm in a 2 mm-thick acrylate polymer nanocomposite containing 61 vol. % CaF 2 nanoparticles. Modeling shows that similar performance could easily be obtained with various inorganic phases relevant to a number of photonic applications

  15. Polaron-electron assisted giant dielectric dispersion in SrZrO{sub 3} high-k dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Borkar, Hitesh; Barvat, Arun; Pal, Prabir; Kumar, Ashok, E-mail: ashok553@nplindia.org [CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-National Physical Laboratory (CSIR-NPL) Campus, Dr. K S Krishnan Marg, New Delhi 110012 (India); Shukla, A. K. [CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Pulikkotil, J. J. [CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-National Physical Laboratory (CSIR-NPL) Campus, Dr. K S Krishnan Marg, New Delhi 110012 (India); Computation and Networking Facility, CSIR-National Physical Laboratory, New Delhi 110012 (India)

    2016-06-07

    The SrZrO{sub 3} is a well known high-k dielectric constant (∼22) and high optical bandgap (∼5.8 eV) material and one of the potential candidates for future generation nanoelectronic logic elements (8 nm node technology) beyond silicon. Its dielectric behavior is fairly robust and frequency independent till 470 K; however, it suffers a strong small-polaron based electronic phase transition (T{sub e}) linking 650 to 750 K. The impedance spectroscopy measurements revealed the presence of conducting grains and grain boundaries at elevated temperature which provide energetic mobile charge carriers with activation energy in the range of 0.7 to 1.2 eV supporting the oxygen ions and proton conduction. X-ray photoemission spectroscopy measurements suggest the presence of weak non-stoichiometric O{sup 2−} anions and hydroxyl species bound to different sites at the surface and bulk. These thermally activated charge carriers at elevated temperature significantly contribute to the polaronic based dielectric anomaly and conductivity. Our dielectric anomaly supports pseudo phase transition due to high degree of change in ZrO{sub 6} octahedral angle in the temperature range of 650–750 K, where electron density and phonon vibration affect the dielectric and conductivity properties.

  16. Essentials of inorganic materials synthesis

    CERN Document Server

    Rao, C N R

    2015-01-01

    This compact handbook describes all the important methods of synthesis employed today for synthesizing inorganic materials. Some features: Focuses on modern inorganic materials with applications in nanotechnology, energy materials, and sustainability Synthesis is a crucial component of materials science and technology; this book provides a simple introduction as well as an updated description of methods Written in a very simple style, providing references to the literature to get details of the methods of preparation when required

  17. Organic-inorganic field effect transistor with SnI-based perovskite channel layer using vapor phase deposition technique

    Science.gov (United States)

    Matsushima, Toshinori; Yasuda, Takeshi; Fujita, Katsuhiko; Tsutsui, Tetsuo

    2003-11-01

    High field-effect hole mobility of (formula available in paper)and threshold voltage is -3.2 V) in organic-inorganic layered perovskite film (formula available in paper)prepared by a vapor phase deposition technique have been demonstrated through the octadecyltrichlorosilane treatment of substrate. Previously, the (formula available in paper)films prepared on the octadecyltrichlorosilane-covered substrates using a vapor evaporation showed not only intense exciton absorption and photoluminescence in the optical spectroscopy but also excellent crystallinity and large grain structure in X-ray and atomic force microscopic studies. Especially, the (formula available in paper)structure in the region below few nm closed to the surface of octadecyltrichlorosilane monolayer was drastically improved in comparison with that on the non-covered substrate. Though our initial (formula available in paper)films via a same sequence of preparation of (formula available in paper)and octadecyltrichlorosilane monolayer did not show the field-effect properties because of a lack of spectral, structural, and morphological features. The unformation of favorable (formula available in paper)structure in the very thin region, that is very important for the field-effect transistors to transport electrons or holes, closed to the surface of non-covered (formula available in paper)dielectric layer was also one of the problems for no observation of them. By adding further optimization and development, such as deposition rate of perovskite, substrate heating during deposition, and tuning device architecture, with hydrophobic treatment, the vacuum-deposited (formula available in paper)have achieved above-described high performance in organic-inorganic hybrid transistors.

  18. Manipulation of dielectric Rayleigh particles using highly focused elliptically polarized vector fields.

    Science.gov (United States)

    Gu, Bing; Xu, Danfeng; Rui, Guanghao; Lian, Meng; Cui, Yiping; Zhan, Qiwen

    2015-09-20

    Generation of vectorial optical fields with arbitrary polarization distribution is of great interest in areas where exotic optical fields are desired. In this work, we experimentally demonstrate the versatile generation of linearly polarized vector fields, elliptically polarized vector fields, and circularly polarized vortex beams through introducing attenuators in a common-path interferometer. By means of Richards-Wolf vectorial diffraction method, the characteristics of the highly focused elliptically polarized vector fields are studied. The optical force and torque on a dielectric Rayleigh particle produced by these tightly focused vector fields are calculated and exploited for the stable trapping of dielectric Rayleigh particles. It is shown that the additional degree of freedom provided by the elliptically polarized vector field allows one to control the spatial structure of polarization, to engineer the focusing field, and to tailor the optical force and torque on a dielectric Rayleigh particle.

  19. Effect of energy emission from evanescent electromagnetic wave at scattering by a dielectric structure

    Energy Technology Data Exchange (ETDEWEB)

    Gulyaev, Yu.V. [Institute of Radioengineering and Electronics of the Russian Academy of Sciences, 125009 Moscow (Russian Federation); Barabanenkov, Yu.N. [Institute of Radioengineering and Electronics of the Russian Academy of Sciences, 125009 Moscow (Russian Federation)]. E-mail: yu.barab@mail.ip.sitek.net; Barabanenkov, M.Yu. [Institute of Microelectronics Technology and High Purity Materials of the Russian Academy of Sciences, 142432 Chernogolovka, Moscow Region (Russian Federation); Nikitov, S.A. [Institute of Radioengineering and Electronics of the Russian Academy of Sciences, 125009 Moscow (Russian Federation)

    2005-02-21

    We present an optical theorem for evanescent (near field) electromagnetic wave scattering by a dielectric structure. The derivation is based on the formalism of angular spectrum wave amplitudes. The optical theorem shows that an energy flux at scattering is emitted in the direction of incident evanescent wave decay.

  20. Determination of the electronic, dielectric, and optical properties of sillenite Bi12TiO20 and perovskite-like Bi4Ti3O12 materials from hybrid first-principle calculations

    KAUST Repository

    Lardhi, Sheikha F.; Noureldine, Dalal; Harb, Moussab; Ziani, Ahmed; Cavallo, Luigi; Takanabe, Kazuhiro

    2016-01-01

    Density functional theory calculation was conducted to determine the optoelectronic properties of bismuthtitanate sillenite (Bi12TiO20) and perovskite-like (Bi4Ti3O12) structures. The lattice parameters were experimentally obtained from Rietveld analysis. The density functional perturbation theory approach was used with the standard Perdew–Burke–Ernzerhof functional and screened Coulomb hybrid Heyd–Scuseria–Ernzerhof functional to investigate the electronic structure and absorption coefficient. Both compounds have good carrier transport properties, low effective hole and electron masses, high dielectric constant, and low exciton binding energy.

  1. Determination of the electronic, dielectric, and optical properties of sillenite Bi12TiO20 and perovskite-like Bi4Ti3O12 materials from hybrid first-principle calculations

    KAUST Repository

    Lardhi, Sheikha F.

    2016-04-05

    Density functional theory calculation was conducted to determine the optoelectronic properties of bismuthtitanate sillenite (Bi12TiO20) and perovskite-like (Bi4Ti3O12) structures. The lattice parameters were experimentally obtained from Rietveld analysis. The density functional perturbation theory approach was used with the standard Perdew–Burke–Ernzerhof functional and screened Coulomb hybrid Heyd–Scuseria–Ernzerhof functional to investigate the electronic structure and absorption coefficient. Both compounds have good carrier transport properties, low effective hole and electron masses, high dielectric constant, and low exciton binding energy.

  2. Reflectance properties of one-dimensional metal-dielectric ternary photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, G. N., E-mail: gnpandey2009@gmail.com [Department of Physics, Amity Institute of Applied Sciences, AmityUniversity, Noida (U.P.) (India); Kumar, Narendra [Department of Physics (CASH), Modi University of Science and Technology, Lakshmangarh, Sikar, Rajsthan (India); Thapa, Khem B. [Department of Physics, U I E T, ChhatrapatiShahu Ji Maharaj University, Kanpur- (UP) (India); Ojha, S. P. [Department of Physics IIT, Banaras Hindu University (India)

    2016-05-06

    Metallic photonic crystal has a very important application in absorption enhancement in solar cells. It has been found that an ultra-thin metallic layer becomes transparent due to internal scattering of light through the each interface of the dielectric and metal surfaces. The metal has absorption due to their surface plasmon and the plasmon has important parameters for changing optical properties of the metal. We consider ternary metallic-dielectric photonic crystal (MDPC) for having large probabilities to change the optical properties of the MDPC and the photonic crystals may be changed by changing dimensionality, symmetry, lattice parameters, Filling fraction and effective refractive index refractive index contrast. In this present communication, we try to show that the photonic band gap in ternary metal-dielectric photonic crystal can be significantly enlarged when air dielectric constant is considered. All the theoretical analyses are made based on the transfer matrix method together with the Drude model of metal.

  3. Photoinduced Giant Dielectric Constant in Lead Halide Perovskite Solar Cells.

    Science.gov (United States)

    Juarez-Perez, Emilio J; Sanchez, Rafael S; Badia, Laura; Garcia-Belmonte, Germá; Kang, Yong Soo; Mora-Sero, Ivan; Bisquert, Juan

    2014-07-03

    Organic-inorganic lead trihalide perovskites have emerged as an outstanding photovoltaic material that demonstrated a high 17.9% conversion efficiency of sunlight to electricity in a short time. We have found a giant dielectric constant (GDC) phenomenon in these materials consisting on a low frequency dielectric constant in the dark of the order of ε0 = 1000. We also found an unprecedented behavior in which ε0 further increases under illumination or by charge injection at applied bias. We observe that ε0 increases nearly linearly with the illumination intensity up to an additional factor 1000 under 1 sun. Measurement of a variety of samples of different morphologies, compositions, and different types of contacts shows that the GDC is an intrinsic property of MAPbX3 (MA = CH3NH3(+)). We hypothesize that the large dielectric response is induced by structural fluctuations. Photoinduced carriers modify the local unit cell equilibrium and change the polarizability, assisted by the freedom of rotation of MA. The study opens a way for the understanding of a key aspect of the photovoltaic operation of high efficiency perovskite solar cells.

  4. Dielectric inspection of erythrocyte morphology

    International Nuclear Information System (INIS)

    Hayashi, Yoshihito; Oshige, Ikuya; Katsumoto, Yoichi; Omori, Shinji; Yasuda, Akio; Asami, Koji

    2008-01-01

    We performed a systematic study of the sensitivity of dielectric spectroscopy to erythrocyte morphology. Namely, rabbit erythrocytes of four different shapes were prepared by precisely controlling the pH of the suspending medium, and their complex permittivities over the frequency range from 0.1 to 110 MHz were measured and analyzed. Their quantitative analysis shows that the characteristic frequency and the broadening parameter of the dielectric relaxation of interfacial polarization are highly specific to the erythrocyte shape, while they are insensitive to the cell volume fraction. Therefore, these two dielectric parameters can be used to differentiate erythrocytes of different shapes, if dielectric spectroscopy is applied to flow-cytometric inspection of single blood cells. In addition, we revealed the applicability and limitations of the analytical theory of interfacial polarization to explain the experimental permittivities of non-spherical erythrocytes

  5. Dielectric inspection of erythrocyte morphology

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Yoshihito; Oshige, Ikuya; Katsumoto, Yoichi; Omori, Shinji; Yasuda, Akio [Life Science Laboratory, Materials Laboratories, Sony Corporation, Sony Bioinformatics Center, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510 (Japan); Asami, Koji [Laboratory of Molecular Aggregation Analysis, Division of Multidisciplinary Chemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)], E-mail: Yoshihito.Hayashi@jp.sony.com

    2008-05-21

    We performed a systematic study of the sensitivity of dielectric spectroscopy to erythrocyte morphology. Namely, rabbit erythrocytes of four different shapes were prepared by precisely controlling the pH of the suspending medium, and their complex permittivities over the frequency range from 0.1 to 110 MHz were measured and analyzed. Their quantitative analysis shows that the characteristic frequency and the broadening parameter of the dielectric relaxation of interfacial polarization are highly specific to the erythrocyte shape, while they are insensitive to the cell volume fraction. Therefore, these two dielectric parameters can be used to differentiate erythrocytes of different shapes, if dielectric spectroscopy is applied to flow-cytometric inspection of single blood cells. In addition, we revealed the applicability and limitations of the analytical theory of interfacial polarization to explain the experimental permittivities of non-spherical erythrocytes.

  6. Silicone-based Dielectric Elastomers

    DEFF Research Database (Denmark)

    Skov, Anne Ladegaard

    Efficient conversion of energy from one form to another (transduction) is an important topic in our daily day, and it is a necessity in moving away from the fossil based society. Dielectric elastomers hold great promise as soft transducers, since they are compliant and light-weight amongst many...... energy efficient solutions are highly sought. These properties allow for interesting products ranging very broadly, e.g. from eye implants over artificial skins over soft robotics to huge wave energy harvesting plants. All these products utilize the inherent softness and compliance of the dielectric...... elastomer transducers. The subject of this thesis is improvement of properties of silicone-based dielectric elastomers with special focus on design guides towards electrically, mechanically, and electromechanically reliable elastomers. Strategies for improving dielectric elastomer performance are widely...

  7. Homogeneity of Inorganic Glasses

    DEFF Research Database (Denmark)

    Jensen, Martin; Zhang, L.; Keding, Ralf

    2011-01-01

    Homogeneity of glasses is a key factor determining their physical and chemical properties and overall quality. However, quantification of the homogeneity of a variety of glasses is still a challenge for glass scientists and technologists. Here, we show a simple approach by which the homogeneity...... of different glass products can be quantified and ranked. This approach is based on determination of both the optical intensity and dimension of the striations in glasses. These two characteristic values areobtained using the image processing method established recently. The logarithmic ratio between...

  8. Structural and dielectric studies on Ag doped nano ZnSnO3

    Science.gov (United States)

    Deepa, K.; Angel, S. Lilly; Rajamanickam, N.; Jayakumar, K.; Ramachandran, K.

    2018-04-01

    Undoped and Ag-doped nano Zinc Stannate (ZSO) ternary oxide were prepared by co-precipitation method. The crystallographic, morphological and optical properties of the synthesized nanoparticles were studied using X-ray diffraction (XRD) and UV-Visible spectroscopy (UV-Vis) and Scanning electron microscopy (SEM). The electrical properties of the synthesized samples were studied by dielectric measurements. Higher concentration Ag doped ZSO nanoparticles exhibit higher dielectric constant at low frequency.

  9. Thermochromic Fluorescence from B18H20(NC5H5)(2): An Inorganic-Organic Composite Luminescent Compound with an Unusual Molecular Geometry

    Czech Academy of Sciences Publication Activity Database

    Londesborough, Michael Geoffrey Stephen; Dolanský, Jiří; Cerdán, L.; Lang, Kamil; Jelínek, Tomáš; Oliva, J. M.; Hnyk, Drahomír; Roca-Sanjuan, D.; Frances-Monerris, A.; Martinčík, Jiří; Nikl, Martin; Kennedy, John David

    2017-01-01

    Roč. 5, č. 6 (2017), č. článku UNSP 1600694. ISSN 2195-1071 R&D Projects: GA ČR(CZ) GA13-09876S Institutional support: RVO:61388980 ; RVO:68378271 Keywords : boranes * energy transfer * fluorescence * solar concentrators * thermochromicity Subject RIV: CA - Inorganic Chemistry ; BH - Optics, Masers, Lasers (FZU-D) OBOR OECD: Inorganic and nuclear chemistry ; Optics (including laser optics and quantum optics) (FZU-D) Impact factor: 6.875, year: 2016

  10. Interconnect Between a Waveguide and a Dielectric Waveguide Comprising an Impedance Matched Dielectric Lens

    Science.gov (United States)

    Decrossas, Emmanuel (Inventor); Chattopadhyay, Goutam (Inventor); Chahat, Nacer (Inventor); Tang, Adrian J. (Inventor)

    2016-01-01

    A lens for interconnecting a metallic waveguide with a dielectric waveguide is provided. The lens may be coupled a metallic waveguide and a dielectric waveguide, and minimize a signal loss between the metallic waveguide and the dielectric waveguide.

  11. Effect of calcination temperature on microstructure, dielectric, magnetic and optical properties of Ba0.7La0.3Fe11.7Co0.3O19 hexaferrites

    International Nuclear Information System (INIS)

    Kaur, Talwinder; Kaur, Barjinder; Bhat, Bilal H.; Kumar, Sachin; Srivastava, A.K.

    2015-01-01

    M-type barium hexaferrite Ba 0.7 La 0.3 Fe 11.7 Co 0.3 O 19 (BaLCM) powder, synthesized using sol gel auto combustion method, heat treated at 700, 900, 1100 and 1200 °C. X ray diffraction (XRD) powder patterns of heat treated samples show the formation of pure phase of M-type hexaferrite after 700 °C. Thermo gravimetric analysis (TGA) reveals that the weight loss of BaLCM becomes constant after 680 °C. The presence of two prominent peaks, at 432 cm −1 and 586 cm −1 in Fourier Transform Infrared Spectroscopy (FT-IR) spectra, gives the idea of formation of M-type hexaferrites. The M–H curve obtained from Vibrating Sample Magnetometer (VSM) were used to calculate saturation magnetization (M S ), retentivity (M r ), squareness ration (SR) and coercivity (H c ). The maximum value of coercivity (5602 Oe) is found at 900 °C. The band gap dependency on temperature was studied using UV–vis NIR spectroscopy. The dielectric constant has been found to be high at low frequency but it decreases with increase in frequency. Such kind of dielectric behavior is explained on the basis of Koop's phenomenological theory and Maxwell Wagner theory

  12. Controlled opacity in a class of nonlinear dielectric media

    Science.gov (United States)

    Bittencourt, E.; Camargo, G. H. S.; De Lorenci, V. A.; Klippert, R.

    2017-03-01

    Motivated by new technologies for designing and tailoring metamaterials, we seek properties for certain classes of nonlinear optical materials that allow room for a reversibly controlled opacity-to-transparency phase transition through the application of external electromagnetic fields. We examine some mathematically simple models for the dielectric parameters of the medium and compute the relevant geometric quantities that describe the speed and polarization of light rays.

  13. Applications of inorganic nanoparticles as therapeutic agents

    Science.gov (United States)

    Kim, Taeho; Hyeon, Taeghwan

    2014-01-01

    During the last decade, various functional nanostructured materials with interesting optical, magnetic, mechanical and chemical properties have been extensively applied to biomedical areas including imaging, diagnosis and therapy. In therapeutics, most research has focused on the application of nanoparticles as potential delivery vehicles for drugs and genes, because nanoparticles in the size range of 2-100 nm can interact with biological systems at the molecular level, and allow targeted delivery and passage through biological barriers. Recent investigations have even revealed that several kinds of nanomaterials are intrinsically therapeutic. Not only can they passively interact with cells, but they can also actively mediate molecular processes to regulate cell functions. This can be seen in the treatment of cancer via anti-angiogenic mechanisms as well as the treatment of neurodegenerative diseases by effectively controlling oxidative stress. This review will present recent applications of inorganic nanoparticles as therapeutic agents in the treatment of disease.

  14. High-frequency dielectric response of polyaniline pellets as nanocomposites of metallic emeraldine salt and dielectric base

    Czech Academy of Sciences Publication Activity Database

    Nuzhnyy, Dmitry; Petzelt, Jan; Rychetský, Ivan; Trchová, Miroslava; Stejskal, Jaroslav

    2015-01-01

    Roč. 209, Nov (2015), s. 561-569 ISSN 0379-6779 R&D Projects: GA ČR GAP204/12/0232; GA ČR(CZ) GAP205/12/0911 Institutional support: RVO:68378271 ; RVO:61389013 Keywords : polyaniline * infrared and THz spectroscopy * optical conductivity * dielectric permittivity * vibrational mode * effective medium approach Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.299, year: 2015

  15. Hybrid Organic/Inorganic Thiol-ene-Based Photopolymerized Networks

    OpenAIRE

    Schreck, Kathleen M.; Leung, Diana; Bowman, Christopher N.

    2011-01-01

    The thiol-ene reaction serves as a more oxygen tolerant alternative to traditional (meth)acrylate chemistry for forming photopolymerized networks with numerous desirable attributes including energy absorption, optical clarity, and reduced shrinkage stress. However, when utilizing commercially available monomers, many thiol-ene networks also exhibit decreases in properties such as glass transition temperature (Tg) and crosslink density. In this study, hybrid organic/inorganic thiol-ene resins ...

  16. Spectroscopic investigations of high-power laser-induced dielectric breakdown in gas mixtures containing carbon monoxide.

    Science.gov (United States)

    Civis, Svatopluk; Babánková, Dagmar; Cihelka, Jaroslav; Sazama, Petr; Juha, Libor

    2008-08-07

    Large-scale plasma was created in gas mixtures containing carbon monoxide by high-power laser-induced dielectric breakdown (LIDB). The composition of the mixtures used corresponded to a cometary and/or meteoritic impact into the Earth's early atmosphere. A multiple-centimeter-sized fireball was created by focusing a single 85 J, 450 ps near-infrared laser pulse into the center of a 15 L gas cell. The excited reaction intermediates that formed in various stages of the LIDB plasma chemical evolution were investigated by optical emission spectroscopy (OES) with temporal resolution. Special attention was paid to any OES signs of molecular ions. However, carbon monoxide cations were registered only if their production was enhanced by Penning ionization, i.e., excess He was added to the CO. The chemical consequences of laser-produced plasma generation in a CO-N 2-H 2O mixture were investigated using high resolution Fourier-transform infrared absorption spectroscopy (FTIR) and gas chromatography (GC). Several simple inorganic and organic compounds were identified in the reaction mixture exposed to ten laser sparks. H 2 (18)O was used to avoid possible contamination. The large laser spark triggered more complex reactivity originating in carbon monoxide than expected, when taking into account the strong triple bond of carbon monoxide causing typically inefficient dissociation of this molecule in electrical discharges.

  17. Optical properties of spherical gold mesoparticles

    DEFF Research Database (Denmark)

    Evlyukhin, A. B.; Kuznetsov, A. I.; Novikov, S. M.

    2012-01-01

    Optical properties of spherical gold particles with diameters of 150-650 nm (mesoparticles) are studied by reflectance spectroscopy. Particles are fabricated by laser-induced transfer of metallic droplets onto metal and dielectric substrates. Contributions of higher multipoles (beyond...

  18. Microstructural and optical properties of spinel oxide M{sub x}Co{sub 2−x}MnO{sub 4} (M = Ni, Zn or Cu; 0 < x < 1) thin films prepared by inorganic polycondensation and dip-coating methods

    Energy Technology Data Exchange (ETDEWEB)

    Le, Thi Ly; Guillemet-Fritsch, Sophie; Dufour, Pascal; Tenailleau, Christophe, E-mail: tenailleau@chimie.ups-tlse.fr

    2016-08-01

    Spinel oxide nanoparticles of M{sub x}Co{sub 2−x}MnO{sub 4} (M = Ni, Zn, Cu; 0 < x < 1) were prepared at 120 °C by the inorganic polycondensation method. Phase composition and microstructure of each sample powder thus obtained were characterized by X-ray diffraction, X-ray fluorescence and scanning electron microscopy. Nanoparticles are well crystallized and uniformly distributed in both shape and size. Colloidal dispersions were stabilized in a low cost and environmentally friendly solvent solution. Spinel oxide thin films were then deposited on glass substrates by using the dip-coating technique. Their optical properties were measured in the 300–1100 nm wavelength range. Thin films show extremely good absorbance in the ultra-violet and blue regions. The highest absorbance observed in the red region was for x = 0.15 in zinc. A smaller direct band gap was determined when a low amount of doping M element was introduced in the cobalt and manganese spinel oxide material. - Highlights: • Pure complex spinel oxide nanoparticles synthesis at low T • Low cost method used to stabilize colloidal dispersions • Preparation of homogenous light absorber thin films by dip-coating • Adjustable optical properties and band gaps with the dopants.

  19. Infrared light extinction by charged dielectric core-coat particles

    OpenAIRE

    Thiessen, Elena; Heinisch, Rafael L.; Bronold, Franz X.; Fehske, Holger

    2014-01-01

    We study the effect of surplus electrons on the infrared extinction of dielectric particles with a core-coat structure and propose to use it for an optical measurement of the particle charge in a dusty plasma. The particles consist of an inner core with negative and an outer coat with positive electron affinity. Both the core and the coat give rise to strong transverse optical phonon resonances, leading to anomalous light scattering in the infrared. Due to the radial profile of the electron a...

  20. Design and characterization of dielectric-loaded plasmonic directional couplers

    DEFF Research Database (Denmark)

    Stær, Tobias Holmgaard; Chen, Zhuo; Bozhevolnyi, Sergey

    2009-01-01

    Ultracompact directional couplers (DCs) based on dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) are analyzed using the effective index method (EIM), with the coupling, both in the parallel interaction region and in- and out-coupling regions, being taken into account. Near-field...... characterization of fabricated DCs performed with a scanning near-field optical microscope verifies the applicability of the EIM in the analysis and design of DLSPPW-based wavelength-selective DCs. The design approach applicable to a large variety of integrated optical waveguides is developed, enabling...

  1. Investigation of the structural, optical and dielectric properties of highly (1 0 0)-oriented (Pb{sub 0.60}Ca{sub 0.20}Sr{sub 0.20})TiO{sub 3} thin films on LaNiO{sub 3} bottom electrode

    Energy Technology Data Exchange (ETDEWEB)

    Pontes, D.S.L. [Laboratorio Interdisciplinar de Eletroquimica e Cerâmica, Department of Chemistry, Universidade Federal de São Carlos, Via Washington Luiz, Km 235, P.O. Box 676, 13565-905 São Carlos, São Paulo (Brazil); Pontes, F.M., E-mail: fenelon@fc.unesp.br [Department of Chemistry, Universidade Estadual Paulista, P.O. Box 473, 17033-360 Bauru, São Paulo (Brazil); Chiquito, A.J. [NanO LaB, Transporte Eletrônico em Nanoestruturas, Department of Physics, Universidade Federal de São Carlos, Via Washington Luiz, Km 235, P.O. Box 676, 13565-905 São Carlos, São Paulo (Brazil); Longo, E. [Laboratorio Interdisciplinar de Eletroquimica e Cerâmica, Department of Chemistry, Universidade Federal de São Carlos, Via Washington Luiz, Km 235, P.O. Box 676, 13565-905 São Carlos, São Paulo (Brazil); Institute of Chemistry, Universidade Estadual Paulista, Araraquara, São Paulo (Brazil)

    2014-07-01

    Highlights: • Highly (h 0 0) oriented LNO and PCST thin films were grown on LAO(1 0 0) substrate. • PCST/LNO/LAO structure shown classic ferroelectric–paraelectric phase transition. • PCST/LNO/LAO structure shows superior dielectric properties. • PCST/LAO films showed a direct allowed optical transition. - Abstract: Highly (1 0 0)-oriented Pb{sub 0.60}Ca{sub 0.20}Sr{sub 0.20}TiO{sub 3}/LNO/LAO structure was fabricated using a chemical deposition process via spin-coating technique. XRD revealed that both LNO and Pb{sub 0.60}Ca{sub 0.20}Sr{sub 0.20}TiO{sub 3} films grown on LAO(1 0 0) substrate and LNO/LAO(1 0 0) structure were crystallized to be highly (h 0 0)-oriented, respectively. AFM images revealed smooth surfaces, spherical-shaped grains and a crack-free surface with a roughness of about 3–7 nm. The tetragonal perovskite phase was confirmed by Raman spectroscopy for Pb{sub 0.60}Ca{sub 0.20}Sr{sub 0.20}TiO{sub 3}/LNO/LAO and Pb{sub 0.60}Ca{sub 0.20}Sr{sub 0.20}TiO{sub 3}/LAO structures. The optical transmittance of 340 nm thick Pb{sub 0.60}Ca{sub 0.20}Sr{sub 0.20}TiO{sub 3} films on a LAO(1 0 0) substrate exhibited an average transmittance above 80% in the wavelength range of 500–1000 nm and an optical band gap E{sub g} of 3.56 and 2.87 eV for the direct and indirect transition processes, respectively. The Au/Pb{sub 0.60}Ca{sub 0.20}Sr{sub 0.20}TiO{sub 3}/LNO/LAO structure has a hysteresis loop with remnant polarization, P{sub r}, of 12 μC/cm{sup 2}, and a coercive field, E{sub c}, of 46 kV/cm for an electric field at 370 kV/cm along with a dielectric constant over 1200.

  2. Preparation of inorganic hydrophobic catalysts

    International Nuclear Information System (INIS)

    Yang, Yong; Wang, Heyi; Du, Yang

    2009-04-01

    In order to catalyse the oxidation of tritium gas, two inorganic hydrophobic catalysts are prepared. Under room temperature, the catalysed oxidation ratio of 0.3%-1% (V/V) hydrogen gas in air is higher than 95%. Pt-II inorganic hydrophobic catalysts has obviously better catalysing ability than Pt-PTFE and lower ability than Pt-SDB in H 2 -HTO isotopic exchange, because the pressure resistence of Pt-II is much higher than Pt-SDB, it can be used to the CECE cell of heavy water detritium system. (authors)

  3. Physical properties of inorganic PMW-PNN-PZT ceramics

    Science.gov (United States)

    Sin, Sang-Hoon; Yoo, Ju-hyun; Kim, Yong-Jin; Baek, Sam-ki; Ha, Jun-Soo; No, Chung-Han; Song, Hyun-Seon; Shin, Dong-Chan

    2015-07-01

    In this work, inorganic Pb(Mg1/2W1/2)0.03(Ni1/3Nb2/3)x(Zr0.5Ti0.5)0.97-xO3 (x = 0.02 ∼ 0.12) composition ceramics were fabricated by the conventional solid state reaction method. And then their micro structure and ferroelectric properties were investigated according to the amount of PNN substitution. Small amounts of Li2CO3 and CaCO3 were used in order to decrease the sintering temperature of the ceramics. The 0.10 mol PNN-substituted PMW-PNN- PZT ceramics sintered at 920°C showed the excellent physical properties of piezoelectric constant (d33), electromechanical coupling factor (kp), mechanical quality coefficient (Qm), and dielectric constant of 566 pC/N, 0.61, 73, and 2183, respectively.

  4. Electrical actuation of dielectric droplets

    International Nuclear Information System (INIS)

    Kumari, N; Bahadur, V; Garimella, S V

    2008-01-01

    Electrical actuation of liquid droplets at the microscale offers promising applications in the fields of microfluidics and lab-on-a-chip devices. Much prior research has targeted the electrical actuation of electrically conducting liquid droplets; however, the actuation of dielectric droplets has remained relatively unexplored, despite the advantages associated with the use of a dielectric droplet. This paper presents modeling and experimental results on the electrical actuation of dielectric droplets between two flat plates. A first-order analytical model, based on the energy-minimization principle, is developed to estimate the electrical actuation force on a dielectric droplet as it moves between two flat plates. Two versions of this analytical model are benchmarked for their suitability and accuracy against a detailed numerical model. The actuation force prediction is then combined with available semi-analytical expressions for predicting the forces opposing droplet motion to develop a model that predicts transient droplet motion under electrical actuation. Electrical actuation of dielectric droplets is experimentally demonstrated by moving transformer oil droplets between two flat plates under the influence of an actuation voltage. Droplet velocities and their dependence on the plate spacing and the applied voltage are experimentally measured and showed reasonable agreement with predictions from the models developed

  5. PARAMETERS OPTIMIZATION OF METAL-DIELECTRIC NANOSTRUCTURES FOR SENSOR APPLICATIONS

    Directory of Open Access Journals (Sweden)

    V. I. Egorov

    2014-07-01

    Full Text Available We present calculation results of optical properties of silver nanoparticles with dielectric shell in relation to their applications in chemical and biosensors. Absorption cross-section calculation for spherical silver nanoparticles was performed by quasi static dipole approximation. It is shown that dielectric shell thickness equal to 2-3 nm and its refraction index equal to 1,5-1,75 are optimal. Calculation results were compared to experimental data. Experimental investigation of metal-dielectric nanostructures sensitivity to external refraction index was performed. Synthesis of silver nanoparticles with dielectric shell on glass surface was performed by nanosecond laser ablation method in near-surface glass layer at 1,06 μm wavelength (Solar LQ129. Synthesis of silver nanoparticles without a shell on the glass surface with silver ions was performed using thermal treatment in wet atmosphere. Spectrophotometer Cary 500 (Varyan was used for spectral measurements. In case of laser ablation method application, external refraction index changes from 1 (the air to 1,33 (water and plasmon resonance band shift for 6 nm occurs. In case of another method application at the same conditions the registered shift was equal to 13 nm. However, in the latter case the particles can be easily removed from the substrate surface. Obtained results will be useful for developing chemical and biological sensors based on plasmon resonance band shift.

  6. Materials Fundamentals of Gate Dielectrics

    CERN Document Server

    Demkov, Alexander A

    2006-01-01

    This book presents materials fundamentals of novel gate dielectrics that are being introduced into semiconductor manufacturing to ensure the continuous scalling of the CMOS devices. This is a very fast evolving field of research so we choose to focus on the basic understanding of the structure, thermodunamics, and electronic properties of these materials that determine their performance in device applications. Most of these materials are transition metal oxides. Ironically, the d-orbitals responsible for the high dielectric constant cause sever integration difficulties thus intrinsically limiting high-k dielectrics. Though new in the electronics industry many of these materials are wel known in the field of ceramics, and we describe this unique connection. The complexity of the structure-property relations in TM oxides makes the use of the state of the art first-principles calculations necessary. Several chapters give a detailed description of the modern theory of polarization, and heterojunction band discont...

  7. Dielectric function of semiconductor superlattice

    International Nuclear Information System (INIS)

    Qin Guoyi.

    1990-08-01

    We present a calculation of the dielectric function for semiconductor GaAs/Ga 1-x Al x As superlattice taking account of the extension of the electron envelope function and the difference of both the dielectric constant and width between GaAs and Ga 1-x Al x As layers. In the appropriate limits, our results exactly reduce to the well-known results of the quasi two-dimensional electron gas obtained by Lee and Spector and of the period array of two-dimensional electron layers obtained by Das Sarma and Quinn. By means of the dielectric function of the superlattice, the dispersion relation of the collective excitation and the screening property of semiconductor superlattice are discussed and compared with the results of the quasi two-dimensional system and with the results of the periodic array of the two-dimensional electron layers. (author). 4 refs, 3 figs

  8. Molecular modeling of inorganic compounds

    National Research Council Canada - National Science Library

    Comba, Peter; Hambley, Trevor W; Martin, Bodo

    2009-01-01

    ... mechanics to inorganic and coordination compounds. Initially, simple metal complexes were modeled, but recently the field has been extended to include organometallic compounds, catalysis and the interaction of metal ions with biological macromolecules. The application of molecular mechanics to coordination compounds is complicated by the numbe...

  9. Inorganic nanomedicine--part 1.

    Science.gov (United States)

    Sekhon, Bhupinder S; Kamboj, Seema R

    2010-08-01

    Inorganic nanomedicine refers to the use of inorganic or hybrid nanomaterials and nanosized objects to achieve innovative medical breakthroughs for drug and gene discovery and delivery, discovery of biomarkers, and molecular diagnostics. Potential uses for fluorescent quantum dots include cell labeling, biosensing, in vivo imaging, bimodal magnetic-luminescent imaging, and diagnostics. Biocompatible quantum dot conjugates have been used successfully for sentinel lymph node mapping, tumor targeting, tumor angiogenesis imaging, and metastatic cell tracking. Magnetic nanowires applications include biosensing and construction of nucleic acids sensors. Magnetic cell therapy is used for the repair of blood vessels. Magnetic nanoparticles (MNPs) are important for magnetic resonance imaging, drug delivery, cell labeling, and tracking. Superparamagnetic iron oxide nanoparticles are used for hyperthermic treatment of tumors. Multifunctional MNPs applications include drug and gene delivery, medical imaging, and targeted drug delivery. MNPs could have a vital role in developing techniques to simultaneously diagnose, monitor, and treat a wide range of common diseases and injuries. From the clinical editor: This review serves as an update about the current state of inorganic nanomedicine. The use of inorganic/hybrid nanomaterials and nanosized objects has already resulted in innovative medical breakthroughs for drug/gene discovery and delivery, discovery of biomarkers and molecular diagnostics, and is likely to remain one of the most prolific fields of nanomedicine. 2010 Elsevier Inc. All rights reserved.

  10. James Moir as Inorganic Chemist

    African Journals Online (AJOL)

    NICO

    KEYWORDS. Inorganic chemistry, gold, atomic theory, history of chemistry. .... Figure 2 (a) shows Moir's model for the C atom, where the black circles represent the ..... Na filled the hole in the F atom, both becoming ions even in the crystal state ...

  11. Determining Inorganic and Organic Carbon.

    Science.gov (United States)

    Koistinen, Jaana; Sjöblom, Mervi; Spilling, Kristian

    2017-11-21

    Carbon is the element which makes up the major fraction of lipids and carbohydrates, which could be used for making biofuel. It is therefore important to provide enough carbon and also follow the flow into particulate organic carbon and potential loss to dissolved organic forms of carbon. Here we present methods for determining dissolved inorganic carbon, dissolved organic carbon, and particulate organic carbon.

  12. Capacitive Cells for Dielectric Constant Measurement

    Science.gov (United States)

    Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco

    2015-01-01

    A simple capacitive cell for dielectric constant measurement in liquids is presented. As an illustrative application, the cell is used for measuring the degradation of overheated edible oil through the evaluation of their dielectric constant.

  13. Dielectric behaviour of strontium tartrate single crystals

    Indian Academy of Sciences (India)

    Unknown

    dielectric loss (tan δ) as functions of frequency and temperature. Ion core type ... Since the data on dielectric properties of strontium tartrate trihydrate (STT) do not ... through 'AE' make 15-amp dimmerstat, the rate of heating was maintained ...

  14. The Dielectric Constant of Lubrication Oils

    National Research Council Canada - National Science Library

    Carey, A

    1998-01-01

    The values of the dielectric constant of simple molecules is discussed first, along with the relationship between the dielectric constant and other physical properties such as boiling point, melting...

  15. Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on tunable functionalized copolymers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede

    2015-01-01

    system, with respect to functionalization, is achieved. It is investigated how the different functionalization variables affect essential DE properties, including dielectric permittivity, dielectric loss, elastic modulus and dielectric breakdown strength, and the optimal degree of chemical......%) was obtained without compromising other vital DE properties such as elastic modulus, gel fraction, dielectric and viscous loss and electrical breakdown strength....

  16. Nanocomposites of TiO2/cyanoethylated cellulose with ultra high dielectric constants

    International Nuclear Information System (INIS)

    Madusanka, Nadeesh; Shivareddy, Sai G; Hiralal, Pritesh; Choi, Youngjin; Amaratunga, Gehan A J; Eddleston, Mark D; Oliver, Rachel A

    2016-01-01

    A novel dielectric nanocomposite containing a high permittivity polymer, cyanoethylated cellulose (CRS) and TiO 2 nanoparticles was successfully prepared with different weight percentages (10%, 20% and 30%) of TiO 2 . The intermolecular interactions and morphology within the polymer nanocomposites were analysed. TiO 2 /CRS nanofilms on SiO 2 /Si wafers were used to form metal–insulator–metal type capacitors. Capacitances and loss factors in the frequency range of 1 kHz–1 MHz were measured. At 1 kHz CRS-TiO 2 nanocomposites exhibited ultra high dielectric constants of 118, 176 and 207 for nanocomposites with 10%, 20% and 30% weight of TiO 2 respectively, significantly higher than reported values of pure CRS (21), TiO 2 (41) and other dielectric polymer-TiO 2 nanocomposite films. Furthermore, all three CRS-TiO 2 nanocomposites show a loss factor <0.3 at 1 kHz and low leakage current densities (10 −6 –10 −7 A cm −2 ). Leakage was studied using conductive atomic force microscopy and it was observed that the leakage is associated with TiO 2 nanoparticles embedded in the CRS polymer matrix. A new class of ultra high dielectric constant hybrids using nanoscale inorganic dielectrics dispersed in a high permittivity polymer suitable for energy management applications is reported. (paper)

  17. Application of phenomenologic approach to an investigation of the induced gyroanisotropic phenomena in dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Kharkyanen, V N; Petrov, E G

    1975-01-01

    The paper presents a group-theoretical method of obtaining the contribution in tensor of transverse dielectrical permeability of magnetic and nonmagnetic dielectrics from specific transitions forbidden in zero approximation in some axial perturbation. The axial perturbation mentioned above permits the transitions and changes the optical symmetry of a crystal in the frequencies of specific transitions depending upon the type of the transition. The external electric and magnetic fields can be chosen as the axial perturbation. This allows one to change the optical symmetry of a crystal in the vicinity of the given transition. (auth)

  18. Hybrid polymer-inorganic photovoltaic cells

    NARCIS (Netherlands)

    Beek, W.J.E.; Janssen, R.A.J.; Merhari, L.

    2009-01-01

    Composite materials made from organic conjugated polymers and inorganic semiconductors such as metal oxides attract considerable interest for photovoltaic applications. Hybrid polymer-inorganic solar cells offer the opportunity to combine the beneficial properties of the two materials in charge

  19. Charge accumulation in lossy dielectrics: a review

    DEFF Research Database (Denmark)

    Rasmussen, Jørgen Knøster; McAllister, Iain Wilson; Crichton, George C

    1999-01-01

    At present, the phenomenon of charge accumulation in solid dielectrics is under intense experimental study. Using a field theoretical approach, we review the basis for charge accumulation in lossy dielectrics. Thereafter, this macroscopic approach is applied to planar geometries such that the mat......At present, the phenomenon of charge accumulation in solid dielectrics is under intense experimental study. Using a field theoretical approach, we review the basis for charge accumulation in lossy dielectrics. Thereafter, this macroscopic approach is applied to planar geometries...

  20. Microscopic theoretical study of frequency dependent dielectric constant of heavy fermion systems

    Science.gov (United States)

    Shadangi, Keshab Chandra; Rout, G. C.

    2017-05-01

    The dielectric polarization and the dielectric constant plays a vital role in the deciding the properties of the Heavy Fermion Systems. In the present communication we consider the periodic Anderson's Model which consists of conduction electron kinetic energy, localized f-electron kinetic energy and the hybridization between the conduction and localized electrons, besides the Coulomb correlation energy. We calculate dielectric polarization which involves two particle Green's functions which are calculated by using Zubarev's Green's function technique. Using the equations of motion of the fermion electron operators. Finally, the temperature and frequency dependent dielectric constant is calculated from the dielectric polarization function. The charge susceptibility and dielectric constant are computed numerically for different physical parameters like the position (Ef) of the f-electron level with respect to fermi level, the strength of the hybridization (V) between the conduction and localized f-electrons, Coulomb correlation potential temperature and optical phonon wave vector (q). The results will be discussed in a reference to the experimental observations of the dielectric constants.

  1. Nonlinear optics at interfaces

    International Nuclear Information System (INIS)

    Chen, C.K.

    1980-12-01

    Two aspects of surface nonlinear optics are explored in this thesis. The first part is a theoretical and experimental study of nonlinear intraction of surface plasmons and bulk photons at metal-dielectric interfaces. The second part is a demonstration and study of surface enhanced second harmonic generation at rough metal surfaces. A general formulation for nonlinear interaction of surface plasmons at metal-dielectric interfaces is presented and applied to both second and third order nonlinear processes. Experimental results for coherent second and third harmonic generation by surface plasmons and surface coherent antiStokes Raman spectroscopy (CARS) are shown to be in good agreement with the theory

  2. Hybrid Organic-Inorganic Perovskite Photodetectors.

    Science.gov (United States)

    Tian, Wei; Zhou, Huanping; Li, Liang

    2017-11-01

    Hybrid organic-inorganic perovskite materials garner enormous attention for a wide range of optoelectronic devices. Due to their attractive optical and electrical properties including high optical absorption coefficient, high carrier mobility, and long carrier diffusion length, perovskites have opened up a great opportunity for high performance photodetectors. This review aims to give a comprehensive summary of the significant results on perovskite-based photodetectors, focusing on the relationship among the perovskite structures, device configurations, and photodetecting performances. An introduction of recent progress in various perovskite structure-based photodetectors is provided. The emphasis is placed on the correlation between the perovskite structure and the device performance. Next, recent developments of bandgap-tunable perovskite and hybrid photodetectors built from perovskite heterostructures are highlighted. Then, effective approaches to enhance the stability of perovskite photodetector are presented, followed by the introduction of flexible and self-powered perovskite photodetectors. Finally, a summary of the previous results is given, and the major challenges that need to be addressed in the future are outlined. A comprehensive summary of the research status on perovskite photodetectors is hoped to push forward the development of this field. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Cellulose Triacetate Dielectric Films For Capacitors

    Science.gov (United States)

    Yen, Shiao-Ping S.; Jow, T. Richard

    1994-01-01

    Cellulose triacetate investigated for use as dielectric material in high-energy-density capacitors for pulsed-electrical-power systems. Films of cellulose triacetate metalized on one or both sides for use as substrates for electrodes and/or as dielectrics between electrodes in capacitors. Used without metalization as simple dielectric films. Advantages include high breakdown strength and self-healing capability.

  4. Improved Dielectric Properties and Energy Storage Density of Poly(vinylidene fluoride-co-hexafluoropropylene) Nanocomposite with Hydantoin Epoxy Resin Coated BaTiO3.

    Science.gov (United States)

    Luo, Hang; Zhang, Dou; Jiang, Chao; Yuan, Xi; Chen, Chao; Zhou, Kechao

    2015-04-22

    Energy storage materials are urgently demanded in modern electric power supply and renewable energy systems. The introduction of inorganic fillers to polymer matrix represents a promising avenue for the development of high energy density storage materials, which combines the high dielectric constant of inorganic fillers with supernal dielectric strength of polymer matrix. However, agglomeration and phase separation of inorganic fillers in the polymer matrix remain the key barriers to promoting the practical applications of the composites for energy storage. Here, we developed a low-cost and environmentally friendly route to modifying BaTiO3 (BT) nanoparticles by a kind of water-soluble hydantoin epoxy resin. The modified BT nanoparticles exhibited homogeneous dispersion in the ferroelectric polymer poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix and strong interfacial adhesion with the polymer matrix. The dielectric constants of the nanocomposites increased significantly with the increase of the coated BT loading, while the dielectric loss of the nanocomposites was still as low as that of the pure P(VDF-HFP). The energy storage density of the nanocomposites was largely enhanced with the coated BT loading at the same electric field. The nanocomposite with 20 vol % BT exhibited an estimated maximum energy density of 8.13 J cm(-3), which was much higher than that of pure P(VDF-HFP) and other dielectric polymers. The findings of this research could provide a feasible approach to produce high energy density materials for practical application in energy storage.

  5. Wavelength-tunable waveguides based on polycrystalline organic-inorganic perovskite microwires

    Science.gov (United States)

    Wang, Ziyu; Liu, Jingying; Xu, Zai-Quan; Xue, Yunzhou; Jiang, Liangcong; Song, Jingchao; Huang, Fuzhi; Wang, Yusheng; Zhong, Yu Lin; Zhang, Yupeng; Cheng, Yi-Bing; Bao, Qiaoliang

    2016-03-01

    Hybrid organic-inorganic perovskites have emerged as new photovoltaic materials with impressively high power conversion efficiency due to their high optical absorption coefficient and long charge carrier diffusion length. In addition to high photoluminescence quantum efficiency and chemical tunability, hybrid organic-inorganic perovskites also show intriguing potential for diverse photonic applications. In this work, we demonstrate that polycrystalline organic-inorganic perovskite microwires can function as active optical waveguides with small propagation loss. The successful production of high quality perovskite microwires with different halogen elements enables the guiding of light with different colours. Furthermore, it is interesting to find that out-coupled light intensity from the microwire can be effectively modulated by an external electric field, which behaves as an electro-optical modulator. This finding suggests the promising applications of perovskite microwires as effective building blocks in micro/nano scale photonic circuits.

  6. Dielectric metasurfaces solve differential and integro-differential equations.

    Science.gov (United States)

    Abdollahramezani, Sajjad; Chizari, Ata; Dorche, Ali Eshaghian; Jamali, Mohammad Vahid; Salehi, Jawad A

    2017-04-01

    Leveraging subwavelength resonant nanostructures, plasmonic metasurfaces have recently attracted much attention as a breakthrough concept for engineering optical waves both spatially and spectrally. However, inherent ohmic losses concomitant with low coupling efficiencies pose fundamental impediments over their practical applications. Not only can all-dielectric metasurfaces tackle such substantial drawbacks, but also their CMOS-compatible configurations support both Mie resonances that are invariant to the incident angle. Here, we report on a transmittive metasurface comprising arrayed silicon nanodisks embedded in a homogeneous dielectric medium to manipulate phase and amplitude of incident light locally and almost independently. By taking advantage of the interplay between the electric/magnetic resonances and employing general concepts of spatial Fourier transformation, a highly efficient metadevice is proposed to perform mathematical operations including solution of ordinary differential and integro-differential equations with constant coefficients. Our findings further substantiate dielectric metasurfaces as promising candidates for miniaturized, two-dimensional, and planar optical analog computing systems that are much thinner than their conventional lens-based counterparts.

  7. Studies on dielectric properties of ferrocenylhydrazone coordinated polymers irradiated by γ-rays

    International Nuclear Information System (INIS)

    Lin Yun; Chen Jie; Lin Zhanru

    2007-01-01

    The three ferrocenylhydrazone coordinated metal polymers were synthesized (PZM). The effect of the 60 Co γ irradiation on microwave dielectric properties and their temperature-dielectric properties were studies. It has been found that the dielectric parameters (ε', tgδ) of coordinated polymers increase along with the absorbed doses and coordinated metals in order Cu, Co, Ni, However, the dependent curves of dielectric parameters on arise-down temperature are universal. On the other hand, the small changes in chemical structure before and after irradiation were confirmed by IR differential spectrometry and SEM. It is possible to make such coordinated polymers as a multifunctional polymeric material with optical, electric and magnetic properties, which may be potentially used in microwave communication. (authors)

  8. How dielectric screening in two-dimensional crystals affects the convergence of excited-state calculations: Monolayer MoS2

    DEFF Research Database (Denmark)

    Hüser, Falco; Olsen, Thomas; Thygesen, Kristian Sommer

    2013-01-01

    We present first-principles many-body calculations of the dielectric constant, quasiparticle band structure, and optical absorption spectrum of monolayer MoS2 using a supercell approach. As the separation between the periodically repeated layers is increased, the dielectric function of the layer...

  9. Subwavelength optics with hyperbolic metamaterials: Waveguides, scattering, and optical topological transitions

    DEFF Research Database (Denmark)

    Ishii, Satoshi; Babicheva, Viktoriia E.; Shalaginov, Mikhail Y.

    2016-01-01

    Hyperbolic metamaterials possess unique optical properties owing to their hyperbolic dispersion. As hyperbolic metamaterials can be constructed just from periodic multilayers of metals and dielectrics, they have attracted considerable attention in the nanophotonics community. Here, we review some...

  10. Dielectric properties of fly ash

    Indian Academy of Sciences (India)

    Unknown

    India's annual coal production is used in about 72 power- generating plants and ... performance of this material as cracking catalyst was investigated with ... Chemically, the FA was silica to an extent of 55–70%, followed by ... Cu, Pb, Cd, Ag, Mn, Fe, Ti, Na, Mo, S, P, Zn and Cl in different ... two-probe method. The dielectric ...

  11. Dielectric polarization in random media

    International Nuclear Information System (INIS)

    Ramshaw, J.D.

    1984-01-01

    The theory of dielectric polarization in random media is systematically formulated in terms of response kernels. The primary response kernel K(12) governs the mean dielectric response at the point r 1 to the external electric field at the point r 2 in an infinite system. The inverse of K(12) is denoted by L(12);. it is simpler and more fundamental than K(12) itself. Rigorous expressions are obtained for the effective dielectric constant epsilon( in terms of L(12) and K(12). The latter expression involves the Onsger-Kirkwood function (epsilon(-epsilon 0 (2epsilon(+epsilon 0 )/epsilon 0 epsilon( (where epsilon 0 is an arbitrary reference value), and appears to be new to the random medium context. A wide variety of series representations for epsilon( are generated by means of general perturbation expansions for K(12) and L(12). A discussion is given of certain pitfalls in the theory, most of which are related to the fact that the response kernels are long ranged. It is shown how the dielectric behavior of nonpolar molecular fluids may be treated as a special case of the general theory. The present results for epsilon( apply equally well to other effective phenomenological coefficients of the same generic type, such as thermal and electrical conductivity, magnetic susceptibility, and diffusion coefficients

  12. Improved di-electric composition

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, R C

    1915-03-29

    An improved di-electric composition is disclosed composed of pitch or bitumen which is melted, and to which is added, while molten, a quantity of finely ground or pulverized spent shale, the whole being mixed or stirred to make a homogeneous composition, substantially as described.

  13. Electrical and dielectrical properties of As-Se-Te glasses

    Czech Academy of Sciences Publication Activity Database

    Kubliha, M.; Kalužný, J.; Pedlíková, Jitka; Zavadil, Jiří; Labaš, V.

    2007-01-01

    Roč. 9, č. 10 (2007), s. 3082-3087 ISSN 1454-4164. [ ANC -3: International Conference on Amourphous and Nanostructured Chalcogenides /3./. Brasov, 02.07.20007-06.07.2007] R&D Projects: GA ČR GA104/02/0799; GA ČR GA104/05/0878 Grant - others:GA SR(SK) APVV-20-043505; GA SR(SK) APVT-20-011304; VEGA(SK) 1/1080/04 Institutional research plan: CEZ:AV0Z20670512; CEZ:AV0Z40320502 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje ; V - iné verejné zdroje Keywords : chalcogenide glasses * electrical conductivity * transmission * dielectric properties Subject RIV: CA - Inorganic Chemistry Impact factor: 0.827, year: 2007

  14. Investigation of the dielectric properties of shale

    International Nuclear Information System (INIS)

    Martemyanov, Sergey M.

    2011-01-01

    The article is dedicated to investigation of the dielectric properties of oil shale. Investigations for samples prepared from shale mined at the deposit in Jilin Province in China were done. The temperature and frequency dependences of rock characteristics needed to calculate the processes of their thermal processing are investigated. Frequency dependences for the relative dielectric constant and dissipation factor of rock in the frequency range from 0,1 Hz to 1 MHz are investigated. The temperature dependences for rock resistance, dielectric capacitance and dissipation factor in the temperature range from 20 to 600°C are studied. Key words: shale, dielectric properties, relative dielectric constant, dissipation factor, temperature dependence, frequency dependence

  15. Attosecond control of electron beams at dielectric and absorbing membranes

    Science.gov (United States)

    Morimoto, Yuya; Baum, Peter

    2018-03-01

    Ultrashort electron pulses are crucial for time-resolved electron diffraction and microscopy of the fundamental light-matter interaction. In this work, we study experimentally and theoretically the generation and characterization of attosecond electron pulses by optical-field-driven compression and streaking at dielectric or absorbing interaction elements. The achievable acceleration and deflection gradient depends on the laser-electron angle, the laser's electric and magnetic field directions, and the foil orientation. Electric and magnetic fields have similar contributions to the final effect and both need to be considered. Experiments and theory agree well and reveal the optimum conditions for highly efficient, velocity-matched electron-field interactions in the longitudinal or transverse direction. We find that metallic membranes are optimum for light-electron control at mid-infrared or terahertz wavelengths, but dielectric membranes are excellent in the visible and near-infrared regimes and are therefore ideal for the formation of attosecond electron pulses.

  16. Significant performance enhancement in AlGaN/GaN high electron mobility transistor by high-κ organic dielectric

    International Nuclear Information System (INIS)

    Ze-Gao, Wang; Yuan-Fu, Chen; Cao, Chen; Ben-Lang, Tian; Fu-Tong, Chu; Xing-Zhao, Liu; Yan-Rong, Li

    2010-01-01

    The electrical properties of AlGaN/GaN high electron mobility transistor (HEMT) with and without high-κ organic dielectrics are investigated. The maximum drain current I D max and the maximum transconductance g m max of the organic dielectric/AlGaN/GaN structure can be enhanced by 74.5%, and 73.7% compared with those of the bare AlGaN/GaN HEMT, respectively. Both the threshold voltage V T and g m max of the dielectric/AlGaN/GaN HEMT are strongly dielectric-constant-dependent. Our results suggest that it is promising to significantly improve the performance of the AlGaN/GaN HEMT by introducing the high-κ organic dielectric. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  17. Inorganic, coordination and organometallic compounds

    International Nuclear Information System (INIS)

    Jursik, F.

    1978-01-01

    Separation of cations and anions of inorganic, coordination and metalloorganic compounds by the method of liquid column chromatography is considered. Common scheme of multicomponent cation mixture is suggesteed. Separation conditions, adsrbents, eluents, pH value solution concenstration, elution rate are also suggested. Separation of rare earth elements Cs, Be, Cd, Te, Th, U, Mo, Re, V, Ru, Zr, In compounds is considered as an example of liquid column chromatography application. Data on column chromatography application are summarized in a table

  18. Correlation between the dielectric constant and X-ray diffraction pattern of Si-O-C thin films with hydrogen bonds

    International Nuclear Information System (INIS)

    Oh, Teresa; Oh, Kyoung Suk; Lee, Kwang-Man; Choi, Chi Kyu

    2004-01-01

    The amorphous structure of organic-inorganic hybrid type Si-O-C thin films was studied using the first principles molecular-dynamics method with density functional techniques. The correlation between the dielectric constant and the degree of amorphous structure in organic-inorganic hybrid type Si-O-C thin films was studied. Si-O-C thin films were deposited by high-density plasma chemical vapor deposition using bis-trimethylsilylmethane and oxygen precursors. As-deposited films and films annealed at 500 deg. C were analyzed by X-ray diffraction (XRD). For quantitative analysis, the X-ray diffraction patterns of the samples were transformed to the radial distribution function (RDF) using Fourier analysis. Hybrid type Si-O-C thin films can be divided into three types using their amorphous structure and the dielectric constant: those with organic, hybrid, and inorganic properties

  19. Optical recording medium

    International Nuclear Information System (INIS)

    Andriech, A.; Bivol, V.; Tridukh, G.; Tsiuleanu, D.

    2002-01-01

    The invention relates of the micro- and optoelectronics, computer engineering ,in particular, to tjhe optical information media and may be used in hilography. Summary of the invention consists in that the optical image recording medium, containing a dielectric substrates, onto one surface of which there are placed in series a transparent electricity conducting layer, a photo sensitive recording layer of chalcogenic glass and a thin film electrode of aluminium, is provided with an optically transparent protective layer, applied into the thin film electrode. The result of the invention consists in excluding the dependence of chemical processes course into the medium upon environmental conditions

  20. Study of two examples of non linear interaction of a laser wave with matter: laser-induced damage of dielectrics and non linear optical properties of organometallic molecules in solution

    International Nuclear Information System (INIS)

    Gaudry, Jean-Baptiste

    2000-01-01

    This research thesis reports the study of two mechanisms of non linear interaction of a laser wave with matter. More particularly, it reports the experimental investigation of non linear optical properties of organometallic molecules in solution, as well as the damage of perfect silica under laser irradiation by using simulation codes. As far as optical properties are concerned, the author highlights the influence of the electronic configuration of the metal present in the organometallic compound, and the influence of the ligand on the second-order non-linear response. As far as the simulation is concerned, some experimental results have been reproduced. This work can be useful for the investigation of the extrinsic damage of imperfect materials, and for the design of experiments of transient measurements of excited silica [fr

  1. High-density carrier-accumulated and electrically stable oxide thin-film transistors from ion-gel gate dielectric.

    Science.gov (United States)

    Fujii, Mami N; Ishikawa, Yasuaki; Miwa, Kazumoto; Okada, Hiromi; Uraoka, Yukiharu; Ono, Shimpei

    2015-12-18

    The use of indium-gallium-zinc oxide (IGZO) has paved the way for high-resolution uniform displays or integrated circuits with transparent and flexible devices. However, achieving highly reliable devices that use IGZO for low-temperature processes remains a technological challenge. We propose the use of IGZO thin-film transistors (TFTs) with an ionic-liquid gate dielectric in order to achieve high-density carrier-accumulated IGZO TFTs with high reliability, and we discuss a distinctive mechanism for the degradation of this organic-inorganic hybrid device under long-term electrical stress. Our results demonstrated that an ionic liquid or gel gate dielectric provides highly reliable and low-voltage operation with IGZO TFTs. Furthermore, high-density carrier accumulation helps improve the TFT characteristics and reliability, and it is highly relevant to the electronic phase control of oxide materials and the degradation mechanism for organic-inorganic hybrid devices.

  2. Near-band-edge optical responses of solution-processed organic-inorganic hybrid perovskite CH3NH3PbI3 on mesoporous TiO2 electrodes

    Science.gov (United States)

    Yamada, Yasuhiro; Nakamura, Toru; Endo, Masaru; Wakamiya, Atsushi; Kanemitsu, Yoshihiko

    2014-03-01

    We studied the near-band-edge optical responses of solution-processed CH3NH3PbI3 on mesoporous TiO2 electrodes, which is utilized in mesoscopic heterojunction solar cells. Photoluminescence (PL) and PL excitation spectra peaks appear at 1.60 and 1.64 eV, respectively. The transient absorption spectrum shows a negative peak at 1.61 eV owing to photobleaching at the band-gap energy, indicating a direct band-gap semiconductor. On the basis of the temperature-dependent PL and diffuse reflectance spectra, we clarified that the absorption tail at room temperature is explained in terms of an Urbach tail and consistently determined the band-gap energy to be ˜1.61 eV at room temperature.

  3. Two-phase mixed media dielectric with macro dielectric beads for enhancing resistivity and breakdown strength

    Science.gov (United States)

    Falabella, Steven; Meyer, Glenn A; Tang, Vincent; Guethlein, Gary

    2014-06-10

    A two-phase mixed media insulator having a dielectric fluid filling the interstices between macro-sized dielectric beads packed into a confined volume, so that the packed dielectric beads inhibit electro-hydrodynamically driven current flows of the dielectric liquid and thereby increase the resistivity and breakdown strength of the two-phase insulator over the dielectric liquid alone. In addition, an electrical apparatus incorporates the two-phase mixed media insulator to insulate between electrical components of different electrical potentials. And a method of electrically insulating between electrical components of different electrical potentials fills a confined volume between the electrical components with the two-phase dielectric composite, so that the macro dielectric beads are packed in the confined volume and interstices formed between the macro dielectric beads are filled with the dielectric liquid.

  4. Optical properties of anisotropic 3D nanoparticles arrays

    Science.gov (United States)

    Santiago, E. Y.; Esquivel-Sirvent, R.

    2017-07-01

    The optical properties of 3D periodic arrays of spheroidal Au nanoparticles are calculated using a Bruggeman effective medium approximation. The optical response of the supra-crystal depends on the volume fraction of the nanoparticles and their aspect or size ratio (major/minor axis). All the nanoparticles have the same orientation, and this defines an anisotropic dielectric function of the crystal. As a function of the filling fraction, while keeping the size ratio fixed, the maximum in the extinction spectra along the major and minor axes does not show a significant change. However, for a fixed filling fraction, varying the aspect ratio of the particles induces a shift of several hundred of nanometers in the maximum of the extinction spectra along the major axis and almost no changes along the minor axis. Depending on the aspect ratio and the filling fraction, we show that the supra-crystal has three regimes with different values of an effective plasma frequency. Contribution to the Focus Issue Self-assemblies of Inorganic and Organic Nanomaterials edited by Marie-Paule Pileni.

  5. Influence of the local structure in phase-change materials on their dielectric permittivity.

    Science.gov (United States)

    Shportko, Kostiantyn V; Venger, Eugen F

    2015-01-01

    Ge-Sb-Te alloys, which belong to the phase-change materials, are promising materials for data storage and display and data visualization applications due to their unique properties. This includes a remarkable difference of their electrical and optical properties in the amorphous and crystalline state. Pronounced change of optical properties for Ge-Sb-Te alloys is linked to the different bonding types and different atomic arrangements in amorphous and crystalline states. The dielectric function of phase-change materials has been investigated in the far infrared (FIR) range. Phonons have been detected by FTIR spectroscopy. Difference of the dispersion of the dielectric permittivity of amorphous and crystalline samples is caused by different structures in different states which contribute to the dielectric permittivity.

  6. Investigation of SiO2 thin films dielectric constant using ellipsometry technique

    Directory of Open Access Journals (Sweden)

    P Sangpour

    2014-11-01

    Full Text Available In this paper, we studied the optical behavior of SiO2 thin films prepared via sol-gel route using spin coating deposition from tetraethylorthosilicate (TEOS as precursor. Thin films were annealed at different temperatures (400-600oC. Absorption edge and band gap of thin layers were measured using UV-Vis spectrophotometery. Optical refractive index and dielectric constant were measured by ellipsometry technique. Based on our atomic force microscopic (AFM and ellipsometry results, thin layers prepared through this method showed high surface area, and high porosity ranging between 4.9 and 16.9, low density 2 g/cm, and low dielectric constant. The dielectric constant and porosity of layers increased by increasing the temperature due to the changes in surface roughness and particle size.

  7. Functional metasurfaces based on metallic and dielectric subwavelength slits and stripes array

    Science.gov (United States)

    Guo, Yinghui; Pu, Mingbo; Li, Xiong; Ma, Xiaoliang; Gao, Ping; Wang, Yanqin; Luo, Xiangang

    2018-04-01

    Starting with the early works of extraordinary optical transmission and extraordinary Young’s interference, researchers have been fascinated by the unusual optical properties displayed by metallic holes/slits and subsequently found similar abnormities in dielectric counterparts. Benefiting from the shrinking wavelength of surface plasmon polaritons excited in metallic slits and high refractive index of dielectric stripes, one can realize local phase modulation and approach desired dispersion by engineering the geometries of a slits and stripes array. In this review, we review recent developments in functional metasurfaces composed of various metallic and dielectric subwavelength slits and stripes arrays, with special emphasis on achromatic, ultra-broadband, quasi-continuous, multifunctional and reconfigurable metasurfaces. Particular attention is paid to provide insight into the design strategies for these devices. Finally, we give an outlook of the development in this fascinating area.

  8. Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation Of Inorganic Nanoparticles And Organic/Inorganic Hybrid Nanocomposites

    Science.gov (United States)

    Pate, Ryan; Lantz, Kevin R.; Dhawan, Anuj; Vo-Dinh, Tuan; Stiff-Roberts, Adrienne D.

    2010-10-01

    In this research, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been used to deposit different classes of inorganic nanoparticles, including bare, un-encapsulated ZnO and Au nanoparticles, as well as ligand-encapsulated CdSe colloidal quantum dots (CQDs). RIR-MAPLE has been used for thin-film deposition of different organic/inorganic hybrid nanocomposites using some of these inorganic nanoparticles, including CdSe CQD-poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-(1-cyanovinylene)phenylene] (MEH-CN-PPV) nanocomposites and Au nanoparticle-poly(methyl methacrylate) (PMMA) nanocomposites. The unique contribution of this research is that a technique is demonstrated for the deposition of organic-based thin-films requiring solvents with bond energies that do not have to be resonant with the laser energy. By creating an emulsion of solvent and ice in the target, RIR-MAPLE using a 2.94 μm laser can deposit most material systems because the hydroxyl bonds in the ice component of the emulsion matrix are strongly resonant with the 2.94 μm laser. In this way, the types of materials that can be deposited using RIR-MAPLE has been significantly expanded. Furthermore, materials with different solvent bond energies can be co-deposited without concern for material degradation and without the need to specifically tune the laser energy to each material solvent bond energy, thereby facilitating the realization of organic/inorganic hybrid nanocomposite thin-films. In addition to the structural characterization of the inorganic nanoparticle and hybrid nanocomposite thin-films deposited using this RIR-MAPLE technique, optical characterization is presented to demonstrate the potential of such films for optoelectronic device applications.

  9. Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation Of Inorganic Nanoparticles And Organic/Inorganic Hybrid Nanocomposites

    International Nuclear Information System (INIS)

    Pate, Ryan; Lantz, Kevin R.; Stiff-Roberts, Adrienne D.; Dhawan, Anuj; Vo-Dinh, Tuan

    2010-01-01

    In this research, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been used to deposit different classes of inorganic nanoparticles, including bare, un-encapsulated ZnO and Au nanoparticles, as well as ligand-encapsulated CdSe colloidal quantum dots (CQDs). RIR-MAPLE has been used for thin-film deposition of different organic/inorganic hybrid nanocomposites using some of these inorganic nanoparticles, including CdSe CQD-poly[2-methoxy-5-(2'-ethylhexyloxy )-1,4-(1-cyanovinylene)phenylene](MEH-CN-PPV) nanocomposites and Au nanoparticle-poly(methyl methacrylate)(PMMA) nanocomposites. The unique contribution of this research is that a technique is demonstrated for the deposition of organic-based thin-films requiring solvents with bond energies that do not have to be resonant with the laser energy. By creating an emulsion of solvent and ice in the target, RIR-MAPLE using a 2.94 μm laser can deposit most material systems because the hydroxyl bonds in the ice component of the emulsion matrix are strongly resonant with the 2.94 μm laser. In this way, the types of materials that can be deposited using RIR-MAPLE has been significantly expanded. Furthermore, materials with different solvent bond energies can be co-deposited without concern for material degradation and without the need to specifically tune the laser energy to each material solvent bond energy, thereby facilitating the realization of organic/inorganic hybrid nanocomposite thin-films. In addition to the structural characterization of the inorganic nanoparticle and hybrid nanocomposite thin-films deposited using this RIR-MAPLE technique, optical characterization is presented to demonstrate the potential of such films for optoelectronic device applications.

  10. Dielectric coatings on metal substrates

    International Nuclear Information System (INIS)

    Glaros, S.S.; Baker, P.; Milam, D.

    1976-01-01

    Large aperture, beryllium substrate-based mirrors have been used to focus high intensity pulsed laser beams. Finished surfaces have high reflectivity, low wavefront distortion, and high laser damage thresholds. This paper describes the development of a series of metallic coatings, surface finishing techniques, and dielectric overcoatings to meet specified performance requirements. Beryllium substrates were coated with copper, diamond-machined to within 5 micro-inches to final contour, nickel plated, and abrasively figured to final contour. Bond strengths for several bonding processes are presented. Dielectric overcoatings were deposited on finished multimetallic substrates to increase both reflectivity and the damage thresholds. Coatings were deposited using both high and low temperature processes which induce varying stresses in the finished coating substrate system. Data are presented to show the evolution of wavefront distortion, reflectivity, and damage thresholds throughout the many steps involved in fabrication

  11. Charge transfer to a dielectric target by guided ionization waves using electric field measurements

    NARCIS (Netherlands)

    Slikboer, E.T.; Garcia-Caurel, E.; Guaitella, O.; Sobota, A.

    2017-01-01

    A kHz-operated atmospheric pressure plasma jet is investigated by measuring charge transferred to a dielectric electro-optic surface (BSO crystal) allowing for the measurement of electric field by exploiting the Pockels effect. The electric field values, distribution of the surface discharge and

  12. Partial loss compensation in dielectric-loaded plasmonic waveguides at near infra-red wavelengths

    DEFF Research Database (Denmark)

    Garcia, Cesar; Coello, Victor; Han, Zhanghua

    2012-01-01

    We report on the fabrication and characterization of straight dielectric-loaded surface plasmon polaritons waveguides doped with lead-sulfide quantum dots as a near infra-red gain medium. A loss compensation of ~33% (an optical gain of ~143 cm^−1) was observed in the guided mode. The mode propaga...

  13. Imaging axial and radial electric field components in dielectric targets under plasma exposure

    NARCIS (Netherlands)

    Slikboer, E.T.; Sobota, A.; Guaitella, O.; Garcia-Caurel, E.

    2018-01-01

    This work presents new ways to investigate the individual electric field components in a dielectric target induced by a non thermal atmospheric pressure plasma jet. Mueller polarimetry is applied to investigate electro-optic crystals under exposure of guided ionization waves produced by a plasma

  14. Photon-pair generation in nonlinear metal-dielectric one-dimensional photonic structures

    Czech Academy of Sciences Publication Activity Database

    Javůrek, D.; Svozilík, J.; Peřina ml., Jan

    2014-01-01

    Roč. 90, č. 5 (2014), "053813-1"-"053813-14" ISSN 1050-2947 R&D Projects: GA ČR GAP205/12/0382 Institutional support: RVO:68378271 Keywords : photon pairs * nonlinear metal-dielectric * one-dimensional photonic structures Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.808, year: 2014

  15. A monolithic relativistic electron beam source based on a dielectric laser accelerator structure

    International Nuclear Information System (INIS)

    McNeur, Josh; Carranza, Nestor; Travish, Gil; Yin Hairong; Yoder, Rodney

    2012-01-01

    Work towards a monolithic device capable of producing relativistic particle beams within a cubic-centimeter is detailed. We will discuss the Micro-Accelerator Platform (MAP), an optical laser powered dielectric accelerator as the main building block of this chip-scale source along with a field enhanced emitter and a region for sub-relativistic acceleration.

  16. On the role of lateral waves in the radiation from the dielectric wedge

    DEFF Research Database (Denmark)

    Balling, Peter

    1973-01-01

    The field on the dielectric wedge is approximated by a plane-wave expansion as in [1]. Contributions from this solution to both the surface field and the radiation field are examined. Finally, an experimental radiation field is compared with the plane-wave solution and with a geometric-optical...

  17. Quantum confinement of zero-dimensional hybrid organic-inorganic polaritons at room temperature

    Science.gov (United States)

    Nguyen, H. S.; Han, Z.; Abdel-Baki, K.; Lafosse, X.; Amo, A.; Lauret, J.-S.; Deleporte, E.; Bouchoule, S.; Bloch, J.

    2014-02-01

    We report on the quantum confinement of zero-dimensional polaritons in perovskite-based microcavity at room temperature. Photoluminescence of discrete polaritonic states is observed for polaritons localized in symmetric sphere-like defects which are spontaneously nucleated on the top dielectric Bragg mirror. The linewidth of these confined states is found much sharper (almost one order of magnitude) than that of photonic modes in the perovskite planar microcavity. Our results show the possibility to study organic-inorganic cavity polaritons in confined microstructure and suggest a fabrication method to realize integrated polaritonic devices operating at room temperature.

  18. Quantum confinement of zero-dimensional hybrid organic-inorganic polaritons at room temperature

    International Nuclear Information System (INIS)

    Nguyen, H. S.; Lafosse, X.; Amo, A.; Bouchoule, S.; Bloch, J.; Han, Z.; Abdel-Baki, K.; Lauret, J.-S.; Deleporte, E.

    2014-01-01

    We report on the quantum confinement of zero-dimensional polaritons in perovskite-based microcavity at room temperature. Photoluminescence of discrete polaritonic states is observed for polaritons localized in symmetric sphere-like defects which are spontaneously nucleated on the top dielectric Bragg mirror. The linewidth of these confined states is found much sharper (almost one order of magnitude) than that of photonic modes in the perovskite planar microcavity. Our results show the possibility to study organic-inorganic cavity polaritons in confined microstructure and suggest a fabrication method to realize integrated polaritonic devices operating at room temperature

  19. Asymmetric Dielectric Elastomer Composite Material

    Science.gov (United States)

    Stewart, Brian K. (Inventor)

    2014-01-01

    Embodiments of the invention provide a dielectric elastomer composite material comprising a plurality of elastomer-coated electrodes arranged in an assembly. Embodiments of the invention provide improved force output over prior DEs by producing thinner spacing between electrode surfaces. This is accomplished by coating electrodes directly with uncured elastomer in liquid form and then assembling a finished component (which may be termed an actuator) from coated electrode components.

  20. Coherent multimoded dielectric wakefield accelerators

    International Nuclear Information System (INIS)

    Power, J.

    1998-01-01

    There has recently been a study of the potential uses of multimode dielectric structures for wakefield acceleration [1]. This technique is based on adjusting the wakefield modes of the structure to constructively interfere at certain delays with respect to the drive bunch, thus providing an accelerating gradient enhancement over single mode devices. In this report we examine and attempt to clarify the issues raised by this work in the light of the present state of the art in wakefield acceleration

  1. Energy storage in ceramic dielectrics

    International Nuclear Information System (INIS)

    Love, G.R.

    1990-01-01

    Historically, multilayer ceramic capacitors (MLC's) have not been considered for energy storage applications for two primary reasons. First, physically large ceramic capacitors were very expensive and, second, total energy density obtainable was not nearly so high as in electrolytic capacitor types. More recently, the fabrication technology for MLC's has improved significantly, permitting both significantly higher energy density and significantly lower costs. Simultaneously, in many applications, total energy storage has become smaller, and the secondary requirements of very low effective series resistance and effective series inductance (which, together, determine how efficiently the energy may be stored and recovered) have become more important. It is therefore desirable to reexamine energy storage in ceramics for contemporary commercial and near-commercial dielectrics. Stored energy is proportional to voltage squared only in the case of paraelectric insulators, because only they have capacitance that is independent of bias voltage. High dielectric constant materials, however, are ferroics (that is ferroelectric and/or antiferroelectric) and display significant variation of effective dielectric constant with bias voltage

  2. Dielectric-filled radiofrequency linacs

    Energy Technology Data Exchange (ETDEWEB)

    Faehl, R J; Keinigs, R K; Pogue, E W [Los Alamos National Lab., NM (United States)

    1997-12-31

    High current, high brightness electron beam accelerators promise to open up dramatic new applications. Linear induction accelerators are currently viewed as the appropriate technology for these applications. A concept by Humphries and Hwang may permit radiofrequency accelerators to fulfill the same functions with greater simplicity and enhanced flexibility. This concept involves the replacement of vacuum rf cavities with dielectric filled ones. Simple analysis indicates that the resonant frequencies are reduced by a factor of ({epsilon}{sub 0}/{epsilon}){sup 1/2} while the stored energy is increased by {epsilon}/{epsilon}{sub 0}. For a high dielectric constant like water, this factor can approach 80. A series of numerical calculations of simple pill-box cavities was performed. Eigenfunctions and resonant frequencies for a full system configuration, including dielectric material, vacuum beamline, and a ceramic window separating the two have been computed. These calculations are compared with the results of a small experimental cavity which have been constructed and operated. Low power tests show excellent agreement. (author). 4 figs., 8 refs.

  3. High index of refraction films for dielectric mirrors prepared by metal-organic chemical vapor deposition

    International Nuclear Information System (INIS)

    Brusasco, R.M.

    1989-01-01

    A wide variety of metal oxides with high index of refraction can be prepared by Metal-Organic Chemical Vapor Deposition. We present some recent optical and laser damage results on oxide films prepared by MOCVD which could be used in a multilayer structure for highly reflecting (HR) dielectric mirror applications. The method of preparation affects both optical properties and laser damage threshold. 10 refs., 8 figs., 4 tabs

  4. Design technique for all-dielectric non-polarizing beam splitter plate

    Science.gov (United States)

    Rizea, A.

    2012-03-01

    There are many situations when, for the proper working, an opto-electronic device requiring optical components does not change the polarization state of light after a reflection, splitting or filtering. In this paper, a design for a non-polarizing beam splitter plate is proposed. Based on certain optical properties of homogeneous dielectric materials we will establish a reliable thin film package formula, excellent for the start of optimization to obtain a 20-nm bandwidth non-polarizing beam splitter.

  5. Nomenclature on an inorganic compound

    International Nuclear Information System (INIS)

    1998-10-01

    This book contains eleven chapters : which mention nomenclature of an inorganic compound with introduction and general principle on nomenclature of compound. It gives the description of grammar for nomenclature such as brackets, diagonal line, asterisk, and affix, element, atom and groups of atom, chemical formula, naming by stoichiometry, solid, neutral molecule compound, ion, a substituent, radical and name of salt, oxo acid and anion on introduction and definition of oxo acid, coordination compound like symbol of stereochemistry , boron and hydrogen compound and related compound.

  6. Enhancement of nonlinear optical properties of compounds of silica

    Indian Academy of Sciences (India)

    The aim of this paper is to introduce a method for enhancing the nonlinear optical properties in silica glass by using metallic nanoparticles. First, the T-matrix method is developed to calculate the effective dielectric constant for the compound of silica glass and metallic nanoparticles, both of which possess nonlinear dielectric ...

  7. Behavior of pentacene initial nucleation on various dielectrics and its effect on carrier transport in organic field-effect transistor.

    Science.gov (United States)

    Qi, Qiong; Yu, Aifang; Wang, Liangmin; Jiang, Chao

    2010-11-01

    The influence of dielectric surface energy on the initial nucleation and the growth of pentacene films as well as the electrical properties of the pentacene-based field-effect transistors are investigated. We have examined a range of organic and inorganic dielectrics with different surface energies, such as polycarbonate/SiO2, polystyrene/SiO2, and PMMA/SiO2 bi-layered dielectrics and also the bare SiO2 dielectric. Atomic force microscopy measurements of sub-monolayer and thick pentacene films indicated that the growth of pentacene film was in Stranski-Kranstanow growth mode on all the dielectrics. However, the initial nucleation density and the size of the first-layered pentacene islands deposited on different dielectrics are drastically influenced by the dielectric surface energy. With the increasing of the surface energy, the nucleation density increased and thus the average size of pentacene islands for the first mono-layer deposition decreased. The performance of fabricated pentacene-based thin film transistors was found to be highly related to nucleation density and the island size of deposited Pentacene film, and it had no relationship to the final particle size of the thick pentacene film. The field effect mobility of the thin film transistor could be achieved as high as 1.38 cm2Ns with on/off ratio over 3 x 10(7) on the PS/SiO2 where the lowest surface energy existed among all the dielectrics. For comparison, the values of mobility and on/off ratio were 0.42 cm2Ns and 1 x 10(6) for thin film transistor deposited directly on bare SiO2 having the highest surface energy.

  8. Solid-state NMR of inorganic semiconductors.

    Science.gov (United States)

    Yesinowski, James P

    2012-01-01

    Studies of inorganic semiconductors by solid-state NMR vary widely in terms of the nature of the samples investigated, the techniques employed to observe the NMR signal, and the types of information obtained. Compared with the NMR of diamagnetic non-semiconducting substances, important differences often result from the presence of electron or hole carriers that are the hallmark of semiconductors, and whose theoretical interpretation can be involved. This review aims to provide a broad perspective on the topic for the non-expert by providing: (1) a basic introduction to semiconductor physical concepts relevant to NMR, including common crystal structures and the various methods of making samples; (2) discussions of the NMR spin Hamiltonian, details of some of the NMR techniques and strategies used to make measurements and theoretically predict NMR parameters, and examples of how each of the terms in the Hamiltonian has provided useful information in bulk semiconductors; (3) a discussion of the additional considerations needed to interpret the NMR of nanoscale semiconductors, with selected examples. The area of semiconductor NMR is being revitalized by this interest in nanoscale semiconductors, the great improvements in NMR detection sensitivity and resolution that have occurred, and the current interest in optical pumping and spintronics-related studies. Promising directions for future research will be noted throughout.

  9. Inorganic Surface Coating with Fast Wetting-Dewetting Transitions for Liquid Manipulations.

    Science.gov (United States)

    Yang, Yajie; Zhang, Liaoliao; Wang, Jue; Wang, Xinwei; Duan, Libing; Wang, Nan; Xiao, Fajun; Xie, Yanbo; Zhao, Jianlin

    2018-06-06

    Liquid manipulation is a fundamental issue for microfluidics and miniaturized sensors. Fast wetting-state transitions by optical methods have proven being efficient for liquid manipulations by organic surface coatings, however rarely been achieved by using inorganic coatings. Here, we report a fast optical-induced wetting-state transition surface achieved by inorganic coating, enabling tens of second transitions for a wetting-dewetting cycle, shortened from an hour, as typically reported. Here, we demonstrate a gravity-driven microfluidic reactor and switch it to a mixer after a second-step exposure in a minimum of within 80 s of UV exposure. The fast wetting-dewetting transition surfaces enable the fast switchable or erasable smart surfaces for water collection, miniature chemical reaction, or sensing systems by using inorganic surface coatings.

  10. Directional interacting whispering-gallery modes in coupled dielectric microdisks

    International Nuclear Information System (INIS)

    Ryu, Jung-Wan; Lee, Soo-Young; Kim, Chil-Min; Park, Young-Jai

    2006-01-01

    We study the optical interaction in a coupled dielectric microdisks by investigating the splitting of resonance positions of interacting whispering-gallery modes (WGM's) and their pattern change, depending on the distance between the microdisks. It is shown that the interaction between the WGM's with odd parity about the y axis becomes appreciable at a distance less than a wavelength and causes directional emissions of the resulting interacting WGM's. The directionality of the interacting WGM's can be understood in terms of an effective boundary deformation in ray dynamical analysis. We also discuss the oscillation of the splitting when the distance is greater than a wavelength

  11. Photoinduced Domain Pattern Transformation in Ferroelectric-Dielectric Superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Youngjun; Park, Joonkyu; Pateras, Anastasios; Rich, Matthew B.; Zhang, Qingteng; Chen, Pice; Yusuf, Mohammed H.; Wen, Haidan; Dawber, Matthew; Evans, Paul G.

    2017-07-01

    The nanodomain pattern in ferroelectric/dielectric superlattices transforms to a uniform polarization state under above-bandgap optical excitation. X-ray scattering reveals a disappearance of domain diffuse scattering and an expansion of the lattice. The reappearance of the domain pattern occurs over a period of seconds at room temperature, suggesting a transformation mechanism in which charge carriers in long-lived trap states screen the depolarization field. A Landau-Ginzburg-Devonshire model predicts changes in lattice parameter and a critical carrier concentration for the transformation.

  12. Flat dielectric metasurface lens array for three dimensional integral imaging

    Science.gov (United States)

    Zhang, Jianlei; Wang, Xiaorui; Yang, Yi; Yuan, Ying; Wu, Xiongxiong

    2018-05-01

    In conventional integral imaging, the singlet refractive lens array limits the imaging performance due to its prominent aberrations. Different from the refractive lens array relying on phase modulation via phase change accumulated along the optical paths, metasurfaces composed of nano-scatters can produce phase abrupt over the scale of wavelength. In this letter, we propose a novel lens array consisting of two neighboring flat dielectric metasurfaces for integral imaging system. The aspherical phase profiles of the metasurfaces are optimized to improve imaging performance. The simulation results show that our designed 5 × 5 metasurface-based lens array exhibits high image quality at designed wavelength 865 nm.

  13. Toxic Gas Removal by Dielectric Discharge with Corona Effect

    International Nuclear Information System (INIS)

    Moreno, H.; Pacheco, M.; Mercado, A.; Cruz, A.; Pacheco, J.; Yousfi, M.; Eichwald, O.; Benhenni, M.

    2006-01-01

    In this work, a theoretical and experimental study on SO2 and NOx removal by non-thermal plasma technology, more specifically a dielectric barrier (DBD) discharge combined with the Corona effect, is presented. Results obtained from a theoretical study describe the chemical kinetic model of SO2 and NOx removal processes; the effect of OH radicals in removal of both gases is noteworthy. Experimental results of de-SO2 process are reported. Also, optical emission spectroscopy study was applied on some atomic helium lines to obtain temperature of electrons in the non-thermal plasma

  14. Manipulation of plasmonic resonances in graphene coated dielectric cylinders

    KAUST Repository

    Ge, Lixin

    2016-11-16

    Graphene sheets can support surface plasmon as the Dirac electrons oscillate collectively with electromagnetic waves. Compared with the surface plasmon in conventional metal (e.g., Ag and Au), graphene plasmonic owns many remarkable merits especially in Terahertz and far infrared frequencies, such as deep sub-wavelength, low loss, and high tunability. For graphene coated dielectric nano-scatters, localized surface plasmon (LSP)exist and can be excited under specific conditions. The LSPs are associated with the Mie resonance modes, leading to extraordinary large scattering and absorption cross section. In this work, we study systematically the optical scattering properties for graphene coated dielectric cylinders. It is found that the LSP can be manipulated by geometrical parameters and external electric gating. Generally, the resonance frequencies for different resonance modes are not the same. However, under proper design, we show that different resonance modes (e.g., dipole mode, quadruple mode etc.) can be excited at the same frequency. Thus, the scattering and absorption by graphene coated dielectric cylinders can indeed overcome the single channel limit. Our finding may open up new avenues in applications for the graphene-based THz optoelectronic devices.

  15. Optical and structural properties of TiO2/Ti/Ag/TiO2 and TiO2/ITO/Ag/ITO/TiO2 metal-dielectric multilayers by RF magnetron sputtering for display application

    International Nuclear Information System (INIS)

    Lee, Jang-Hoon; Lee, Seung-Hyu; Hwangbo, Chang-Kwon; Lee, Kwang-Su

    2004-01-01

    Electromagnetic-interference (EMI) shielding and near-infrared (NIR) cutoff filters for plasma display panels, based on fundamental structures (ITO/Ag/ITO), (TiO 2 /Ti/Ag/TiO 2 ) and (TiO 2 /ITO/Ag/ITO/TiO 2 ), were designed and prepared by RF-magnetron sputtering. The optical, structural and electrical properties of the filters were investigated by using spectrophotometry, Auger electron spectroscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy, atomic force microscopy and four-point-probe measurements. The results show that ITO films as the barriers and base layers lead to higher transmittance in the visible spectrum and smoother surface roughness than Ti metal barriers, while maintaining high NIR cutoff characteristics and chemical stability, which may be attributed to the lower absorption in the interfacial layers and better protection of the Ag layers by the ITO layers.

  16. Synthesis, Properties and Mineralogy of Important Inorganic Materials

    CERN Document Server

    Warner, Terence E

    2010-01-01

    Intended as a textbook for courses involving preparative solid-state chemistry, this book offers clear and detailed descriptions on how to prepare a selection of inorganic materials that exhibit important optical, magnetic and electrical properties, on a laboratory scale. The text covers a wide range of preparative methods and can be read as separate, independent chapters or as a unified coherent body of work. Discussions of various chemical systems reveal how the properties of a material can often be influenced by modifications to the preparative procedure, and vice versa. References to miner

  17. Development of a dielectric ceramic based on diatomite-titania part two: dielectric properties characterization

    Directory of Open Access Journals (Sweden)

    Medeiros Jamilson Pinto

    1998-01-01

    Full Text Available Dielectric properties of sintered diatomite-titania ceramics are presented. Specific capacitance, dissipation factor, quality factor and dielectric constant were determined as a function of sintering temperature, titania content and frequency; the temperature coefficient of capacitance was measured as a function of frequency. Besides leakage current, the dependence of the insulation resistance and the dielectric strength on the applied dc voltage were studied. The results show that diatomite-titania compositions can be used as an alternative dielectric.

  18. Heat-resistant inorganic binders.

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich,

    2017-04-01

    Full Text Available The authors consider some aspects of production of inorganic heat-resistant composite materials in which new classes of inorganic binders - the basic salts of various metals – are applied. The possibility to use hydroxochlorides and hydroxonitrates of aluminum, zirconium, chromium and a number of other metals as the binder has been shown. The main products of the thermal decomposition of all types of binders discussed in this paper are nano-dispersed highly refractory oxides. Increased pressure in the manufacture of these materials shifts the position of the minimum of the dependence «production strength – production temperature» in the direction of low temperatures. This effect is caused by decreased film thickness of the binder located between filler particles and hence by increased rate of transfer of the matter to the interface and by facilitated sintering process. Materials based on the systems containing chromium and some other elements in transitional oxidation states are colour. For this reason, they have the worst thermal conductivity under the same heat resistance compared to colorless materials.

  19. Electrical breakdown phenomena of dielectric elastomers

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Yu, Liyun; Skov, Anne Ladegaard

    2017-01-01

    Silicone elastomers have been heavily investigated as candidates for dielectric elastomers and are as such almost ideal candidates with their inherent softness and compliance but they suffer from low dielectric permittivity. This shortcoming has been sought optimized by many means during recent...... years. However, optimization with respect to the dielectric permittivity solely may lead to other problematic phenomena such as premature electrical breakdown. In this work, we investigate the electrical breakdown phenomena of various types of permittivity-enhanced silicone elastomers. Two types...... of silicone elastomers are investigated and different types of breakdown are discussed. Furthermore the use of voltage stabilizers in silicone-based dielectric elastomers is investigated and discussed....

  20. Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on dipolar copolymers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede

    2014-01-01

    Dielectric elastomers (DES) are a promising new transducer technology, but high driving voltages limit their current commercial potential. One method used to lower driving voltage is to increase dielectric permittivity of the elastomer. A novel silicone elastomer system with high dielectric...