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Sample records for selective optical films

  1. Spatially selective optical tuning of quantum dot thin film luminescence.

    PubMed

    Chen, Jixin; Chan, Yang-Hsiang; Yang, Tinglu; Wark, Stacey E; Son, Dong Hee; Batteas, James D

    2009-12-30

    Photolithographically generated patterns have been created on immobilized CdSe QD thin films by fine-tuning their optical properties (intensity and emission wavelength) postsynthetically. These optically modified QDs show enhanced selectivity for binding of different ligands, affording the ability to fabricate optically reconfigurable surfaces for display or sensing applications. The patterns may be readily generated with any typical optical lithographic approach.

  2. Cadmium stannate selective optical films for solar energy applications

    NASA Technical Reports Server (NTRS)

    Haacke, G.

    1975-01-01

    Efforts concentrated on reducing the electrical sheet resistance of sputtered cadmium stannate films, installing and testing equipment for spray coating experiments, and sputter deposition of thin cadmium sulfide layers onto cadmium stannate electrodes. In addition, single crystal silicon wafers were coated with cadmium stannate. Work also continued on the development of the backwall CdS solar cell.

  3. Methanol selective fibre-optic gas sensor with a nanoporous thin film of organic-inorganic hybrid multilayers

    NASA Astrophysics Data System (ADS)

    Wang, T.; Okuda, H.; Lee, S.-W.

    2015-07-01

    The development of an evanescent wave optical fibre (EWOF) sensor modified with an organic-inorganic hybrid nanoporous thin film for alcohol vapor detection was demonstrated. The optical fibre with a core diameter of 200 μm was bent into U-shape probe optic fibre to enhance the penetation depth of light transferred into the evanescent filed. The bended region of the fibre was modified with a multilayered thin film of poly(allyamine hydrochloride) and silica nanoparticels, (PAH/SiO2)n, by a layer-by-layer (LbL) film deposition technique, followed by infusion of tetrakis(4- sulfophenyl)porphine, TPPS. The mesoporous film structure showed high sensitivity and selectivity to methanol by the aid of the TPPS infused inside the film. The optical sensor response was reversible and reproducible over many times of exposures to analytes, which was caused by the change in refractive index (RI) of the film.

  4. Selective inorganic thin films

    SciTech Connect

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T.

    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.

  5. Thin Film Optical Coatings

    NASA Astrophysics Data System (ADS)

    Ristau, Detlev; Ehlers, Henrik

    Within the scientific conception of the modern world, thin film optical coatings can be interpreted as one-dimensional photonic crystals. In general, they are composed of a sequence of single layers which consist of different transparent dielectrics with a thickness in the nanometer scale according to the operation wavelength range. The major function of these photonic structures is to adapt the properties of an optical surface to the needs of specific applications. By application of optical thin film coatings with optimized designs, the spectral characteristics of a surface can be modified to practically any required transfer function for a certain wavelength range. For example, the Fresnel reflection of a lens or a laser window can be suppressed for a broad wavelength range by depositing an antireflective coating containing only a few single layers. On the basis of a layer stack with alternating high- and low-refracting materials, high reflectance values up to 99.999% can be achieved for a certain laser wavelength. In addition to these basic functions, optical coatings can realize a broad variety of spectral filter characteristics according to even extremely sophisticated demands in modern precision optics and laser technology. Moreover, recent developments in optical thin film technology provide the means to combine selected optical properties with other features concerning, for instance, the thermal, mechanical or chemical stability of a surface. The latest progress in ophthalmic coatings even includes the integration of self-cleaning, photoactive or anti-fogging functions in antireflective coatings on glass.

  6. Fluoride Selective Optical Sensor Based on Aluminum(III)-Octaethylporphyrin in Thin Polymeric Film: Further Characterization and Practical Application

    PubMed Central

    Badr, Ibrahim H. A.; Meyerhoff, Mark E.

    2008-01-01

    More detailed analytical studies of a new fluoride selective optical sensor based on the use of aluminum(III)-octaethylporphyrin and a lipophilic pH indicator (4′,5′-dibromofluorescein octadecyl ester; ETH-7075) within a thin plasticized poly(vinyl chloride) film are reported. The sensor exhibits extraordinary optical selectivity for fluoride over a wide range of other anions, including anions with far more positive free energies of hydration (e.g., perchlorate, thiocyanate, nitrate, etc.). UV-VIS spectrophotometric studies of the sensing films indicate that fluoride interacts with the Al(III) center of the porphyrin structure, yielding both a change in the Soret band λmax of the porphyrin as well as a change in the protonation state of the pH indicator within the film. The same change in spectral properties of the metalloporphyrin occurs in the absence of added pH indicator or with added tetraphenylborate derivative anionic sites, but optical responses to fluoride in these cases are shown to be irreversible. The presence of the pH indicator and the simultaneous fluoride/proton coextraction equilibrium chemistry is shown to greatly enhance the reversibility of fluoride binding to the Al(III) porphyrin. Optical response toward fluoride can be observed in the range of 0.1 μM to 1.6 mM. Optical selectivity coefficients of < 10−6 for common anions (e.g., sulfate, chloride, nitrate etc.) and < 10−4 for perchlorate and thiocyanate are obtained. Measurements of fluoride in drinking water via the new optical sensor are shown to correlate well with values obtained for the same samples using a classical LaF3 based fluoride ion-selective electrode method. PMID:16223262

  7. Optical thin film devices

    NASA Astrophysics Data System (ADS)

    Mao, Shuzheng

    1991-11-01

    Thin film devices are applied to almost all modern scientific instruments, and these devices, especially optical thin film devices, play an essential role in the performances of the instruments, therefore, they are attracting more and more attention. Now there are numerous kinds of thin film devices and their applications are very diversified. The 300-page book, 'Thin Film Device and Applications,' by Prof. K. L. Chopra gives some general ideas, and my paper also outlines the designs, fabrication, and applications of some optical thin film devices made in my laboratory. Optical thin film devices have been greatly developed in the recent decades. Prof. A. Thelan has given a number of papers on the theory and techniques, Prof. H. A. Macleod's book, 'Thin Film Optical Filters,' has concisely concluded the important concepts of optical thin film devices, and Prof. J. A. Dobrowobski has proposed many successful designs for optical thin film devices. Recently, fully-automatic plants make it easier to produce thin film devices with various spectrum requirements, and some companies, such as Balzers, Leybold AG, Satis Vacuum AG, etc., have manufactured such kinds of coating plants for research or mass-production, and the successful example is the production of multilayer antireflection coatings with high stability and reproducibility. Therefore, it could be said that the design of optical thin film devices and coating plants is quite mature. However, we cannot expect that every problem has been solved, the R&D work still continues, the competition still continues, and new design concepts, new techniques, and new film materials are continually developed. Meanwhile, the high-price of fully-automatic coating plants makes unpopular, and automatic design of coating stacks is only the technique for optimizing the manual design according to the physical concepts and experience, in addition, not only the optical system, but also working environment should be taken into account when

  8. An optical sensor based on H-acid/layered double hydroxide composite film for the selective detection of mercury ion.

    PubMed

    Sun, Zhiyong; Jin, Lan; Zhang, Shitong; Shi, Wenying; Pu, Min; Wei, Min; Evans, David G; Duan, Xue

    2011-09-19

    A novel optical chemosensor was fabricated based on 1-amino-8-naphthol-3,6-disulfonic acid sodium (H-acid) intercalated layered double hydroxide (LDH) film via the electrophoretic deposition (EPD) method. The film of H-acid/LDH with the thickness of 1 μm possesses a well c-orientation of the LDH microcrystals confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The fluorescence detection for Hg(II) in aqueous solution was performed by using the H-acid/LDH film sensor at pH 7.0, with a linear response range in 1.0 × 10(-7) to 1.0 × 10(-5) mol L(-1) and a detection limit of 6.3 × 10(-8) mol L(-1). Furthermore, it exhibits excellent selectivity for Hg(II) over a large number of competitive cations including alkali, alkaline earth, heavy metal and transitional metals. The specific fluorescence response of the optical sensor is attributed to the coordination between Hg(II) and sulfonic group in the H-acid immobilized in the LDH matrix, which was verified by NMR spectroscopy and UV-vis spectra. In addition, density functional theory (DFT) calculation further confirms that the coordination occurs between one Hg(2+) and two O atoms in the sulfonic group, which is responsible for the significant fluorescence quenching of the H-acid/LDH film. The results indicate that the H-acid/LDH composite film can be potentially used as a chemosensor for the detection of Hg(2+) in the environmental and biomedical field.

  9. Direct optical carbon dioxide sensing based on a polymeric film doped with a selective molecular tweezer-type ionophore.

    PubMed

    Xie, Xiaojiang; Pawlak, Marcin; Tercier-Waeber, Mary-Lou; Bakker, Eric

    2012-04-03

    A novel optical method for the determination of CO(2) concentration in aqueous and gaseous samples of plasticized PVC film is presented. The detection principle makes use of a direct molecular recognition of the carbonate ion by a molecular tweezer-type ionophore, which has previously been demonstrated to exhibit excellent carbonate selectivity. The carbonate ion is extracted together with hydrogen ions into a polymeric film that contains the anion exchanger tridodecylmethylammonium chloride, a lipophilic, electrically charged, and highly basic pH indicator, which is used for the readout in absorbance mode, in addition to the lipophilic carbonate ionophore. According to known bulk optode principles, such an optical sensor responds to the product of the carbonate ion activity and the square of hydrogen ion activity. This quantity is thermodynamically linked to the activity of carbon dioxide. This allows one to realize a direct carbon dioxide sensor that does not make use of the traditional Severinghaus sensing principle of measuring a pH change upon CO(2) equilibration across a membrane. A selectivity analysis shows that common ions such as chloride are sufficiently suppressed for direct PCO(2) measurements in freshwater samples at pH 8. Chloride interference, however, is too severe for direct seawater measurements at the same pH. This may be overcome by placing a gas-permeable membrane over the optode sensing film. This is conceptually confirmed by establishing that the sensor is equally useful for gas-phase PCO(2) measurements. As expected, humid air samples are required for proper sensor functioning, as dry CO(2) gas will not cause any signal change. The sensor showed acceptable response times and good reproducibility under both conditions.

  10. Nonlinear optical thin films

    NASA Technical Reports Server (NTRS)

    Leslie, Thomas M.

    1993-01-01

    A focused approach to development and evaluation of organic polymer films for use in optoelectronics is presented. The issues and challenges that are addressed include: (1) material synthesis, purification, and the tailoring of the material properties; (2) deposition of uniform thin films by a variety of methods; (3) characterization of material physical properties (thermal, electrical, optical, and electro-optical); and (4) device fabrication and testing. Photonic materials, devices, and systems were identified as critical technology areas by the Department of Commerce and the Department of Defense. This approach offers strong integration of basic material issues through engineering applications by the development of materials that can be exploited as the active unit in a variety of polymeric thin film devices. Improved materials were developed with unprecedented purity and stability. The absorptive properties can be tailored and controlled to provide significant improvement in propagation losses and nonlinear performance. Furthermore, the materials were incorporated into polymers that are highly compatible with fabrication and patterning processes for integrated optical devices and circuits. By simultaneously addressing the issues of materials development and characterization, keeping device design and fabrication in mind, many obstacles were overcome for implementation of these polymeric materials and devices into systems. We intend to considerably improve the upper use temperature, poling stability, and compatibility with silicon based devices. The principal device application that was targeted is a linear electro-optic modulation etalon. Organic polymers need to be properly designed and coupled with existing integrated circuit technology to create new photonic devices for optical communication, image processing, other laser applications such as harmonic generation, and eventually optical computing. The progression from microscopic sample to a suitable film

  11. Nonlinear optical thin films

    NASA Technical Reports Server (NTRS)

    Leslie, Thomas M.

    1993-01-01

    A focused approach to development and evaluation of organic polymer films for use in optoelectronics is presented. The issues and challenges that are addressed include: (1) material synthesis, purification, and the tailoring of the material properties; (2) deposition of uniform thin films by a variety of methods; (3) characterization of material physical properties (thermal, electrical, optical, and electro-optical); and (4) device fabrication and testing. Photonic materials, devices, and systems were identified as critical technology areas by the Department of Commerce and the Department of Defense. This approach offers strong integration of basic material issues through engineering applications by the development of materials that can be exploited as the active unit in a variety of polymeric thin film devices. Improved materials were developed with unprecedented purity and stability. The absorptive properties can be tailored and controlled to provide significant improvement in propagation losses and nonlinear performance. Furthermore, the materials were incorporated into polymers that are highly compatible with fabrication and patterning processes for integrated optical devices and circuits. By simultaneously addressing the issues of materials development and characterization, keeping device design and fabrication in mind, many obstacles were overcome for implementation of these polymeric materials and devices into systems. We intend to considerably improve the upper use temperature, poling stability, and compatibility with silicon based devices. The principal device application that was targeted is a linear electro-optic modulation etalon. Organic polymers need to be properly designed and coupled with existing integrated circuit technology to create new photonic devices for optical communication, image processing, other laser applications such as harmonic generation, and eventually optical computing. The progression from microscopic sample to a suitable film

  12. Thin θ -film optics

    NASA Astrophysics Data System (ADS)

    Huerta, Luis

    2016-12-01

    A Chern-Simons theory in 3D is accomplished by the so-called θ term in the action (θ /2 )∫F ∧F , which contributes only to observable effects on the boundaries of such a system. When electromagnetic radiation interacts with the system, the wave is reflected and its polarization is rotated at the interface, even when both the θ system and the environment are pure vacuum. These topics have been studied extensively. Here, we investigate the optical properties of a thin θ film, where multiple internal reflections could interfere coherently. The cases of pure vacuum and a material with magnetoelectric properties are analyzed. It is found that the film reflectance is enhanced compared to ordinary non-θ systems and the interplay between magnetoelectric properties and the θ parameter yield film opacity and polarization properties which could be interesting in the case of topological insulators, among other topological systems.

  13. Selective growth of ZnO thin film nanostructures: Structure, morphology and tunable optical properties

    SciTech Connect

    Krishnakanth, Katturi Naga; Sunandana, C. S.; Rajesh, Desapogu E-mail: mperd@nus.edu.sg

    2016-05-23

    The ZnO nanostructures (spherical, rod shape) have been successfully fabricated via a thermal evaporation followed by dip coating method. The pure, doped ZnO thin films were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM) and UV-Vis spectroscopy, respectively. A possible growth mechanism of the spherical, rod shape ZnO nanostructures are discussed. XRD patterns revealed that all films consist of pure ZnO phase and were well crystallized with preferential orientation towards (002) direction. Doping by PVA, PVA+Cu has effective role in the enhancement of the crystalline quality and increases in the band gap.

  14. Thin-film optical initiator

    DOEpatents

    Erickson, Kenneth L.

    2001-01-01

    A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.

  15. Thin-Film Selective Emitter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Lowe, Roland A.

    1993-01-01

    Direct conversion of thermal energy into electrical energy using a photovoltaic cell is called thermophotovoltaic energy conversion. One way to make this an efficient process is to have the thermal energy source be an efficient selective emitter of radiation. The emission must be near the band-gap energy of the photovoltaic cell. One possible method to achieve an efficient selective emitter is the use of a thin film of rare-earth oxides. The determination of the efficiency of such an emitter requires analysis of the spectral emittance of the thin film including scattering and reflectance at the vacuum-film and film-substrate interfaces. Emitter efficiencies (power emitted in emission band/total emitted power) in the range 0.35-0.7 are predicted. There is an optimum optical depth to obtain maximum efficiency. High emitter efficiencies are attained only for low (less than 0.05) substrate emittance values, both with and without scattering. The low substrate emittance required for high efficiency limits the choice of substrate materials to highly reflective metals or high-transmission materials such as sapphire.

  16. Optical constants of V{sub 1{minus}x}W{sub x}O{sub 2} thermochromic films and their application to the selective radiating material

    SciTech Connect

    Tazawa, Masato; Jin, P.; Tanemura, Sakae

    1995-12-31

    Tungsten doped vanadium oxide (V{sub 1{minus}x}W{sub x}O{sub 2}) films are known to be reliable thermochromic materials for their semiconductor/metal transition temperature which can be controlled by the doping level x. In this paper, firstly, the optical constants of V{sub 1{minus}x}W{sub x}O{sub 2} films on glass substrate were determined from the reflectance spectra and the transmittance spectra measured at 25 C and 80 C in the wavelength region from 300 to 2,500 nm. In the determination the authors used Drude model in the high temperature metallic-phase and the least square method in the low temperature semiconductor-phase. The calculated reflectance spectra and the transmittance spectra using the Drude model with adequate values of the parameters are consistent with the measured ones in whole spectral region in the high temperature phase. Secondarily, the authors carried out a simulation of radiative cooling power of some selective radiating materials whose substrates were V{sub 1{minus}x}W{sub x}O{sub 2} films, using the optical constants in IR region obtained by the extrapolation of the obtained ones in visible and near IR region. As the high temperature phase of V{sub 1{minus}x}W{sub x}O{sub 2} has high reflectivity, the authors can use this thermochromic film as a substrate of the selective radiating material which consists of an adequate film on a high reflective substrate. The simulation shows the capability of automatic temperature control of the radiative cooling system tandemed by SiO film, V{sub 1{minus}x}W{sub x}O{sub 2} film, and the black substrate by different doping level x.

  17. Optically-selected AGN

    NASA Astrophysics Data System (ADS)

    Richard, Gordon

    2016-08-01

    will discuss the selection and properties of optically-selected AGN as contrasted with other multi-wavelength investigations. While optical surveys are able to identify *more* AGNs than other wavelengths, this size comes with a bias towards brighter, unobscured sources. Although optical surveys are not ideal for probing obscured AGNs, I will discuss how they can guide our search for them. The bias towards unobscured sources in the optical is partially mitigated, however, by an increase in information content for the sources that *are* identified---in the form of physics probed by the combination of optical continuum, absorption, and emission. An example is the ability to estimate the mass of AGNs based on the optical/UV emission lines. I will discuss the range of mass (and accretion rate) probed by the optical in addition to serious biases in the black hole mass scaling relations that corrupt these estimates at high redshift.

  18. Selective inorganic thin films

    SciTech Connect

    Phillips, M.L.F.; Pohl, P.I.; Brinker, C.J.

    1997-04-01

    Separating light gases using membranes is a technology area for which there exists opportunities for significant energy savings. Examples of industrial needs for gas separation include hydrogen recovery, natural gas purification, and dehydration. A membrane capable of separating H{sub 2} from other gases at high temperatures could recover hydrogen from refinery waste streams, and facilitate catalytic dehydrogenation and the water gas shift (CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction. Natural gas purification requires separating CH{sub 4} from mixtures with CO{sub 2}, H{sub 2}S, H{sub 2}O, and higher alkanes. A dehydrating membrane would remove water vapor from gas streams in which water is a byproduct or a contaminant, such as refrigeration systems. Molecular sieve films offer the possibility of performing separations involving hydrogen, natural gas constituents, and water vapor at elevated temperatures with very high separation factors. It is in applications such as these that the authors expect inorganic molecular sieve membranes to compete most effectively with current gas separation technologies. Cryogenic separations are very energy intensive. Polymer membranes do not have the thermal stability appropriate for high temperature hydrogen recovery, and tend to swell in the presence of hydrocarbon natural gas constituents. The authors goal is to develop a family of microporous oxide films that offer permeability and selectivity exceeding those of polymer membranes, allowing gas membranes to compete with cryogenic and adsorption technologies for large-scale gas separation applications.

  19. Optical Characterization of Molecular Contaminant Films

    NASA Technical Reports Server (NTRS)

    Visentine, James T.

    2007-01-01

    A semi-empirical method of optical characterization of thin contaminant films on surfaces of optical components has been conceived. The method was originally intended for application to films that become photochemically deposited on such optical components as science windows, lenses, prisms, thinfilm radiators, and glass solar-cell covers aboard spacecraft and satellites in orbit. The method should also be applicable, with suitable modifications, to thin optical films (whether deposited deliberately or formed as contaminants) on optical components used on Earth in the computer microchip laser communications and thin-film industries. The method is expected to satisfy the need for a means of understanding and predicting the reductions in spectral transmittance caused by contaminant films and the consequent deterioration of performances of sensitive optical systems. After further development, this method could become part of the basis of a method of designing optical systems to minimize or compensate for the deleterious effects of contaminant films. In the original outer-space application, these deleterious effects are especially pronounced because after photochemical deposition, the films become darkened by further exposure to solar vacuum ultraviolet (VUV) radiation. In this method, thin contaminant films are theoretically modeled as thin optical films, characterized by known or assumed values of thickness, index of refraction, and absorption coefficient, that form on the outer surfaces of the original antireflection coating on affected optical components. The assumed values are adjusted as needed to make actual spectral transmittance values approximate observed ones as closely as possible and to correlate these values with amounts of VUV radiation to which the optical components have been exposed. In an initial study, the method was applied in correlating measured changes in transmittance of high-purity fused silica photochemically coated with silicone films of

  20. Inorganic optical dielectric films

    NASA Astrophysics Data System (ADS)

    Woollam, John A.

    1996-07-01

    Dielectric coatings have been in use for a very long time, yet today they represent a steadily growing wold-wide industry. A wide range of materials, and applications from the near ultraviolet into the infrared are in use, or under development. This paper is a brief survey, including references to the literature, and a discussion of materials diagnostics. Discussed is the microstructure, optical constants and their relationship as determined especially by optical measurements. This paper emphasizes the materials science aspects rather than applications.

  1. Optical Nonlinearity in DNA Films.

    DTIC Science & Technology

    1988-06-15

    properties of DNA implied by our discovery of counter ion effects on the optical polarizability of DNA ( Weidlich , Lindsay and Rupprechi. Biopolymers 26, 439...spectra. 2a: "The Origin of the A to B Transition in DNA Fibers and Filns" S.M. Lindsay. S.A. Lee. J.W. Powell. T. Weidlich . C. DeMarco, G.D. Lewen...Scattering Study of the Hydration of Li- and Na-DNA films" S.A. Lee. S.M. Lindsay. J.W. Powell. T. Weidlich . N.J. Tao and G.D. Lewen. Biopolymers. 26. 1637

  2. Transparency Film for Demonstration of Biaxial Optics.

    ERIC Educational Resources Information Center

    Camp, Paul R.

    1994-01-01

    Explains why transparency film demonstrates biaxial optical properties. Provides detailed descriptions of the procedure and equipment needed for large-scale optics demonstrations of the polarization interference pattern produced by biaxial crystals. (DDR)

  3. Polarization selecting optical element using a porro prism incorporating a thin film polarizer in a single element

    DOEpatents

    Hendrix, James Lee

    2001-05-08

    A Porro prism and a light polarizer are combined in a single optical element termed a Hendrix Prism. The design provides retro-reflection of incoming light of a predetermined polarization in a direction anti-parallel to the direction of light incidence, while reflecting undesired light, i.e., that having a polarization orthogonal to the predetermined polarization, from the surface of the light polarizer. The undesired light is reflected in a direction that does not interfere with the intended operation of the device in which the Hendrix Prism is installed yet provides feedback to the system in which it is used.

  4. Polarization selecting Optical Element using a Porro Prism Incorporating a thin film Polarizer in a single element

    SciTech Connect

    Hendrix, James lee

    2000-01-28

    A Porro prism and a light polarizer are combined in a single optical element termed a Hendrix Prism. The design provides retro-reflection of incoming light of a predetermined polarization in a direction anti-parallel to the direction of light incidence, while reflecting undesired light, i.e., that having a polarization orthogonal to the predetermined polarization, from the surface of the light polarizer. The undesired light is reflected in a direction that does not interfere with the intended operation of the device in which the Hendrix Prism is installed yet provides feedback to the system in which it is used.

  5. Optical Films For Solar Energy Applications

    NASA Astrophysics Data System (ADS)

    Lampert, Carl M.

    1983-11-01

    Stratified optical materials and coatings play an important role in improving the efficiency of solar conversion processes. At present the best-known stratified media are multilayer and graded-index films. Stratified media are used as heat mirrors, selective absorbers, antireflective films, and transparent insulation. Graded-index films can be homogenous materials, spatially oriented structures, or etched materials. Such films and materials improve efficiency and allow for innovation in energy-efficient windows, passive and active energy conversion, and photovoltaics. The horizons of invention can be expanded by considering new materials, techniques, and concepts that can increase the efficiency of energy utilization in buildings and transform solar energy into heat, light and electrical power. The stability requirements for materials to effectively collect and transmit solar energy are extremely demanding. This, coMbined with the need for inexpensive production methods, creates a broad area for innovative scientific research. We describe several approaches and materials systems for two broad application categories: 1) low-conductance, high-transmittance systems and 2) solar absorbers.

  6. Model selection for radiochromic film dosimetry.

    PubMed

    Méndez, I

    2015-05-21

    The purpose of this study was to find the most accurate model for radiochromic film dosimetry by comparing different channel independent perturbation models. A model selection approach based on (algorithmic) information theory was followed, and the results were validated using gamma-index analysis on a set of benchmark test cases. Several questions were addressed: (a) whether incorporating the information of the non-irradiated film, by scanning prior to irradiation, improves the results; (b) whether lateral corrections are necessary when using multichannel models; (c) whether multichannel dosimetry produces better results than single-channel dosimetry; (d) which multichannel perturbation model provides more accurate film doses. It was found that scanning prior to irradiation and applying lateral corrections improved the accuracy of the results. For some perturbation models, increasing the number of color channels did not result in more accurate film doses. Employing Truncated Normal perturbations was found to provide better results than using Micke-Mayer perturbation models. Among the models being compared, the triple-channel model with Truncated Normal perturbations, net optical density as the response and subject to the application of lateral corrections was found to be the most accurate model. The scope of this study was circumscribed by the limits under which the models were tested. In this study, the films were irradiated with megavoltage radiotherapy beams, with doses from about 20-600 cGy, entire (8 inch  × 10 inch) films were scanned, the functional form of the sensitometric curves was a polynomial and the different lots were calibrated using the plane-based method.

  7. Films Containing Optically Nonlinear Diacetylene Monomer

    NASA Technical Reports Server (NTRS)

    Paley, Mark S.; Mcmanus, Samuel P.; Frazier, Donald O.

    1993-01-01

    Solid films exhibiting nonlinear optical properties prepared as mixtures of poly(methyl methacrylate) with various amounts of diacetylene monomer called "compound 1" in article, "Synthesizing Diacetylenes With Nonlinear Optical Properties" (MFS-26186). Useful as phase-conjugate mirrors in laser-beam communications and as optical switches in optical computers. This particular diacetylene monomer exhibits strong third-order nonlinear optical properties, both in pure form and in solution.

  8. Numerical simulation and rational design of optically anisotropic columnar films

    NASA Astrophysics Data System (ADS)

    Leontyev, Viktor A.; Hawkeye, Matthew M.; Wakefield, Nicholas G.; Tabunshchyk, Kyrylo; Sit, Jeremy C.; Kovalenko, Andriy; Brett, Michael J.

    2011-03-01

    Optical anisotropy is an inherent property of columnar dielectric films, such as those fabricated by the glancing angle deposition (GLAD) technique. This process utilizes physical vapor deposition combined with computer-controlled substrate motion to finely tune the direction of column growth and vital morphological parameters such as column cross-section and inter-columnar spacing. Control over the anisotropic properties of the porous film provides an opportunity to design polarization-selective photonic devices and films with improved band gap properties. Anisotropic defects in multilayer films also result in a polarization-sensitive position of resonant transmission modes. We employed the finite-difference time-domain and frequency-domain methods to theoretically analyze and design columnar films with unique band-gap properties. The following morphologies were considered: (i) S-shaped columnar films with polarization-dependent band-gap position and width. Using numerical simulations we have shown that the competitive effect of different sources of anisotropy can be used to engineer photonic band gaps with strong selectivity to linearly-polarized light; (ii) Rugate thin films with an anisotropic defect, which exhibit resonant mode splitting. Optical devices were fabricated using titanium dioxide because it has good transparency in the visible range of the optical spectrum and a large bulk refractive index. Experimental results were compared to simulations to verify the designs and understand the limitations of the fabrication process.

  9. All optical switching in henna thin film

    NASA Astrophysics Data System (ADS)

    Henari, Fryad Z.; Jasim, Khalil E.

    2013-08-01

    The optical nonlinearity in henna (Lawson (2- hydroxyl-1,4 naphthoquinone) film was utilized to demonstrate all optical switching. The nonlinear absorption of the henna film was calculated by measuring the transmission of the laser beam ( λ = 488 nm) as a function of incident light intensities. The observed nonlinear absorption is attributed to a two-photon absorption process. The pump and probe technique was used to demonstrate all optical switching. The switching characteristics can be utilized to generate all-optical logic gates such as simple inverter switches (NOT) NOR, AND NAND logic functions.

  10. Tear film measurement by optical reflectometry technique

    PubMed Central

    Lu, Hui; Wang, Michael R.; Wang, Jianhua; Shen, Meixiao

    2014-01-01

    Abstract. Evaluation of tear film is performed by an optical reflectometer system with alignment guided by a galvanometer scanner. The reflectometer system utilizes optical fibers to deliver illumination light to the tear film and collect the film reflectance as a function of wavelength. Film thickness is determined by best fitting the reflectance-wavelength curve. The spectral reflectance acquisition time is 15 ms, fast enough for detecting film thickness changes. Fast beam alignment of 1 s is achieved by the galvanometer scanner. The reflectometer was first used to evaluate artificial tear film on a model eye with and without a contact lens. The film thickness and thinning rate have been successfully quantified with the minimum measured thickness of about 0.3 μm. Tear films in human eyes, with and without a contact lens, have also been evaluated. A high-contrast spectral reflectance signal from the precontact lens tear film is clearly observed, and the thinning dynamics have been easily recorded from 3.69 to 1.31 μm with lipid layer thickness variation in the range of 41 to 67 nm. The accuracy of the measurement is better than ±0.58% of the film thickness at an estimated tear film refractive index error of ±0.001. The fiber-based reflectometer system is compact and easy to handle. PMID:24500519

  11. Tear film measurement by optical reflectometry technique.

    PubMed

    Lu, Hui; Wang, Michael R; Wang, Jianhua; Shen, Meixiao

    2014-02-01

    Evaluation of tear film is performed by an optical reflectometer system with alignment guided by a galvanometer scanner. The reflectometer system utilizes optical fibers to deliver illumination light to the tear film and collect the film reflectance as a function of wavelength. Film thickness is determined by best fitting the reflectance-wavelength curve. The spectral reflectance acquisition time is 15 ms, fast enough for detecting film thickness changes. Fast beam alignment of 1 s is achieved by the galvanometer scanner. The reflectometer was first used to evaluate artificial tear film on a model eye with and without a contact lens. The film thickness and thinning rate have been successfully quantified with the minimum measured thickness of about 0.3 μm. Tear films in human eyes, with and without a contact lens, have also been evaluated. A high-contrast spectral reflectance signal from the precontact lens tear film is clearly observed, and the thinning dynamics have been easily recorded from 3.69 to 1.31 μm with lipid layer thickness variation in the range of 41 to 67 nm. The accuracy of the measurement is better than ±0.58% of the film thickness at an estimated tear film refractive index error of ±0.001. The fiber-based reflectometer system is compact and easy to handle.

  12. Optical Properties of Epitaxially Grown Silver Films

    NASA Astrophysics Data System (ADS)

    Wu, Yanwen; Zhang, Chendong; Zhang, Matt; Shih, Chih-Kang; Li, Xiaoqin

    2013-03-01

    One major obstacle in the advancing field of plasmonics is the loss in metals. A sizable contribution of this loss comes from grain boundaries and surface roughness introduced during thin film growth using conventional deposition methods. A novel epitaxial growth technique is used to produce silver (Ag) thin films free of such flaws. We investigate the optical properties-namely the dielectric optical constants-of these new epitaxial films in the bulk region and in the ultrathin film limit where quantum mechanical behaviors emerge due to energy quantization in the growth direction. The values for the dielectric optical constants are extracted from the spectral ellipsometry (SE) measurements over a wide range of optical frequencies. By using an adequate model of the sample structure and initial values of the fitting parameters (i.e. the real and imaginary parts of the optical constants), we can extract these measured values for the new Ag films. We have confirmed that in the bulk region, the optical constants converge with the well-known Johnson and Christy measurements. In the ultrathin film limit, however, we observed significant changes near the D-band transition likely due to a quantum well-like density of states. Equal contribution. Also affiliated with Department of Physics, The University of South Carolina, Columbia, SC 29208

  13. Thin film ferroelectric electro-optic memory

    NASA Technical Reports Server (NTRS)

    Thakoor, Sarita (Inventor); Thakoor, Anilkumar P. (Inventor)

    1993-01-01

    An electrically programmable, optically readable data or memory cell is configured from a thin film of ferroelectric material, such as PZT, sandwiched between a transparent top electrode and a bottom electrode. The output photoresponse, which may be a photocurrent or photo-emf, is a function of the product of the remanent polarization from a previously applied polarization voltage and the incident light intensity. The cell is useful for analog and digital data storage as well as opto-electric computing. The optical read operation is non-destructive of the remanent polarization. The cell provides a method for computing the product of stored data and incident optical data by applying an electrical signal to store data by polarizing the thin film ferroelectric material, and then applying an intensity modulated optical signal incident onto the thin film material to generate a photoresponse therein related to the product of the electrical and optical signals.

  14. Optically clear film for tactile interfaces

    NASA Astrophysics Data System (ADS)

    Yairi, Micah

    2016-09-01

    For years, rigid plastics dominated as cover lenses in mobile and computing devices before being replaced by rigid glass sheets, which have become the current de facto standard. This is changing again. Optically clear, soft polymer films and film stacks now offer a promising alternative to glass. These polymer films provide a fundamentally different user experience, dramatically improving the user experience of writing and drawing, while also providing good durability. Tactus has developed an optically clear stack of polymer materials for use in a writing-first device. Details, usability studies, and performance data will be presented.

  15. Thin Films for X-ray Optics

    NASA Astrophysics Data System (ADS)

    Conley, Raymond

    Focusing x-rays with refraction requires an entire array of lens instead of a single element, each contributing a minute amount of focusing to the system. In contrast to their visible light counterparts, diffractive optics require a certain depth along the optical axis in order to provide sufficient phase shift. Mirrors reflect only at very shallow angles. In order to increase the angle of incidence, contribution from constructive interference within many layers needs to be collected. This requires a multilayer coating. Thin films have become a central ingredient for many x-ray optics due to the ease of which material composition and thickness can be controlled. Chapter 1 starts with a short introduction and survey of the field of x-ray optics. This begins with an explanation of reflective multilayers. Focusing optics are presented next, including mirrors, zone plates, refractive lenses, and multilayer Laue lens (MLL). The strengths and weaknesses of each "species" of optic are briefly discussed, alongside fabrication issues and the ultimate performance for each. Practical considerations on the use of thin-films for x-ray optics fabrication span a wide array of topics including material systems selection and instrumentation design. Sputter deposition is utilized exclusively for the work included herein because this method of thin-film deposition allows a wide array of deposition parameters to be controlled. This chapter also includes a short description of two deposition systems I have designed. Chapter 2 covers a small sampling of some of my work on reflective multilayers, and outlines two of the deposition systems I have designed and built at the Advanced Photon Source. A three-stripe double multilayer monochromator is presented as a case study in order to detail specifications, fabrication, and performance of this prolific breed of x-ray optics. The APS Rotary Deposition System was the first deposition system in the world designed specifically for multilayer

  16. Optical Properties of Thin Film Molecular Mixtures

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Shumway, Dean A.; Lyons, Valerie (Technical Monitor)

    2002-01-01

    Thin films composed of molecular mixtures of metal and dielectric are being considered for use as solar selective coatings for a variety of space power applications. By controlling the degree of molecular mixing, the solar selective coatings can be tailored to have the combined properties of high solar absorptance, alpha, and low infrared emittance, epsilon. On orbit, these combined properties would simultaneously maximize the amount of solar energy captured by the coating and minimize the amount of thermal energy radiated. Mini-satellites equipped with solar collectors coated with these cermet coatings may utilize the captured heat energy to power a heat engine to generate electricity, or to power a thermal bus that directs heat to remote regions of the spacecraft. Early work in this area identified the theoretical boundary conditions needed to operate a Carnot cycle in space, including the need for a solar concentrator, a solar selective coating at the heat inlet of the engine, and a radiator. A solar concentrator that can concentrate sunlight by a factor of 100 is ideal. At lower values, the temperature of the solar absorbing surface becomes too low for efficient heat engine operation, and at higher values, cavity type heat receivers become attractive. In designing the solar selective coating, the wavelength region yielding high solar absorptance must be separated from the wavelength region yielding low infrared emittance by establishing a sharp transition in optical properties. In particular, a sharp transition in reflectance is desired in the infrared to achieve the desired optical performance. For a heat engine operating at 450C, a sharp transition at 1.8 micrometers is desired. The radiator completes the heat flow through the Carnot cycle. Additional work has been done supporting the use of molecular mixtures for terrestrial applications. Sputter deposition provides a means to apply coatings to the tubes that carry a working fluid at the focus of trough

  17. Optical Properties of Thin Film Molecular Mixtures

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Shumway, Dean A.

    2003-01-01

    Thin films composed of molecular mixtures of metal and dielectric are being considered for use as solar selective coatings for a variety of space power applications. By controlling the degree of molecular mixing, the solar selective coatings can be tailored to have the combined properties of high solar absorptance, , and low infrared emittance, . On orbit, these combined properties would simultaneously maximize the amount of solar energy captured by the coating and minimize the amount of thermal energy radiated. Mini-satellites equipped with solar collectors coated with these cermet coatings may utilize the captured heat energy to power a heat engine to generate electricity, or to power a thermal bus that directs heat to remote regions of the spacecraft. Early work in this area identified the theoretical boundary conditions needed to operate a Carnot cycle in space, including the need for a solar concentrator, a solar selective coating at the heat inlet of the engine, and a radiator.1 A solar concentrator that can concentrate sunlight by a factor of 100 is ideal. At lower values, the temperature of the solar absorbing surface becomes too low for efficient heat engine operation, and at higher values, cavity type heat receivers become attractive. In designing the solar selective coating, the wavelength region yielding high solar absorptance must be separated from the wavelength region yielding low infrared emittance by establishing a sharp transition in optical properties. In particular, a sharp transition in reflectance is desired in the infrared to achieve the desired optical performance. For a heat engine operating at 450 C, a sharp transition at 1.8 micrometers is desired.2 The radiator completes the heat flow through the Carnot cycle.

  18. Optical properties of thin nanosilicon films

    NASA Astrophysics Data System (ADS)

    Buchenko, Viktor V.; Rodionova, Tatiana V.; Sutyagina, Anastasia S.; Goloborodko, Andrey A.; Multian, Volodymyr V.; Uklein, Andrii V.; Gayvoronsky, Volodymyr Ya.

    2016-12-01

    Present paper is devoted to the investigation of the nanosilicon films internal structure effect on optical properties. Atomic force microscopy results reveal that the films with different thickness have fundamentally different grain size distribution (samples with the film thickness less than 50 nm have single-mode grain size distribution, while samples with the film thickness more than 50 nm have multi-mode distribution of grain size). The correlation between grain size of nanosilicon films, photoluminescence and scattering indicatrix was shown. Well-isolated vibronic structures were observed on the ultraviolet-visible photoluminescence spectrum from nanosilicon films with the thickness more than 10 nm. The photoluminescence spectra in the red range correlate with the nanosilicon grain size distribution due to the effect of the quantum confinement. However, due to the complex shape of the grains mathematical modeling of photoluminescence spectrum is complicated. Both scattering indicatrix and photoluminescence reveal the multi-mode grain size distribution of the films with thickness more than 50 nm. The comparative analysis of theoretical results of optical radiation scattering by nanosilicon films with experimental ones is illustrated. Mathematical modeling of the scattering indicatrix shows the correlation of average grain size from scattering and photoluminescence data.

  19. Selective optical contacting for solar spectrum management

    NASA Astrophysics Data System (ADS)

    Yang, Jianfeng; Chen, Weijian; Wang, Bo; Zhang, Zhilong; Huang, Shujuan; Shrestha, Santosh; Wen, Xiaoming; Patterson, Robert; Conibeer, Gavin

    2017-02-01

    Solar spectrum management using up/down conversion is an important method to improve the photovoltaic energy conversion efficiency. It asks for a monochromatic luminescence absorption at the band edge of the photovoltaic device to reduce both the sub-band-gap and over-band-gap energy losses. Here, we demonstrate an energy selective optical contacting concept to improve the luminescence transfer efficiency for spectrum management. By increasing both the luminescence emission and re-absorption ability through photonic resonance, an efficient photon transfer channel could be established between the luminescence emitter and the photovoltaic component in a near-field region. This concept is not only able to compensate the insufficient band edge absorption ability of the photovoltaic device, but also to break the far-field limitation of luminescence radiation. The energy selection on the optical spectrum naturally imposed by the mode resonance is also helpful to improve the monochromaticity of the luminescence yield. In this paper, a photonic crystal cavity is used to realize the optical contacting concept between a thin silicon film and spectrum converter. The optical power and photon flux transferred between different components are calculated analytically using the electromagnetic Green's function. The corresponding radiative dipole moment is estimated by the fluctuation-dissipation theorem. The example shows an over 80 times enhancement in the luminescence absorbance by the silicon layer, illustrating the great potential of this concept to be applied on nano-structured photovoltaic devices.

  20. A Directory of Selective Corrections Films.

    ERIC Educational Resources Information Center

    Lankes, George A.

    This directory of selective film titles has been prepared to serve as a ready index to many of the films of potential value for the enrichment of a corrections curriculum. Recognizing that the list is not complete, the directory has been assembled in a manner which allows for adding titles by alphabetic sequence on the blank sides of the pages.…

  1. Thin-film optical shutter. Final report

    SciTech Connect

    Matlow, S.L.

    1981-02-01

    A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, has been chosen as the one most likely to meet all of the requirements of the Thin Film Optical Shutter project (TFOS). The reason for this choice is included. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a new quantum mechanical method was developed - Equilibrium Bond Length (EBL) Theory. Some results of EBL Theory are included.

  2. Optical properties of a photopolymer film for digital holographic storage

    NASA Astrophysics Data System (ADS)

    Shin, Changwon; Kim, Junghoi; Kim, Nam; Lee, Hyojin; Kim, Eunkyoung

    2005-09-01

    Tir- and mono functional monomers were dispersed in a solution of polysulfone in organic solvent containing a photo initiator and other additives. New photopolymer film was prepared by dispersing acrylic monomer in a polysulfone matrix. The Polysulfone was adopted as a binder since it affords transparent thick films with low dimensional changes during holographic recording. Optical property of the photopolymer showed high diffraction efficiency (>90%) under an optimized optical condition at 532nm laser. The angular selectivity for angular multiplexing page oriented holographic memories (POHMs), the maximum diffraction efficiency of the material during holographic recording, the diffraction efficiency of the films as a function of an incident angle of two beams, exposure energy for saturation of the holographic material and application for holographic data storage will be discussed.

  3. Direct-patterned optical waveguides on amorphous silicon films

    DOEpatents

    Vernon, Steve; Bond, Tiziana C.; Bond, Steven W.; Pocha, Michael D.; Hau-Riege, Stefan

    2005-08-02

    An optical waveguide structure is formed by embedding a core material within a medium of lower refractive index, i.e. the cladding. The optical index of refraction of amorphous silicon (a-Si) and polycrystalline silicon (p-Si), in the wavelength range between about 1.2 and about 1.6 micrometers, differ by up to about 20%, with the amorphous phase having the larger index. Spatially selective laser crystallization of amorphous silicon provides a mechanism for controlling the spatial variation of the refractive index and for surrounding the amorphous regions with crystalline material. In cases where an amorphous silicon film is interposed between layers of low refractive index, for example, a structure comprised of a SiO.sub.2 substrate, a Si film and an SiO.sub.2 film, the formation of guided wave structures is particularly simple.

  4. Thin films from hydrophilic poly(N,N-dimethyl acrylamide) copolymers as optical indicators for humidity

    NASA Astrophysics Data System (ADS)

    Lazarova, K.; Todorova, L.; Christova, D.; Vasileva, M.; Georgiev, R.; Madjarova, V.; Babeva, T.

    2017-01-01

    In the present paper we study thin films from poly(N,N-dimethyl acrylamide)-poly(ethylene oxide) (PDMAA/PEO) copolymers of different composition and structure in order to implement them as sensitive media for optical indicators for humidity. PDMAA/PEO di- and triblock copolymers were synthesized via redox polymerization in aqueous media. Thin films were deposited on silicon substrates by spin coating method using polymers solutions with appropriate concentrations. Refractive index, extinction coefficient and thickness of the films are calculated from reflectance spectra of the films deposited on silicon substrates using non-linear curve fitting method. Sensing properties of the films were tested by films exposure to different humidity levels followed by in-situ monitoring of the changes in the optical properties. The influence of the polymer structure and postdeposition annealing on the optical and sensing properties of the films was investigated. The potential application of selected polymers for optical sensing of humidity were demonstrated and discussed.

  5. Optical properties of {beta}-Sn films

    SciTech Connect

    Takeuchi, Katsuki; Adachi, Sadao

    2009-04-01

    Optical properties of white tin ({beta}-Sn) have been investigated using spectroscopic ellipsometry in the photon-energy range between 0.6 and 6.5 eV at room temperature. The {beta}-Sn films are deposited by vacuum evaporation on Si(001) substrates. The structural properties of the films are evaluated by x-ray diffraction and ex situ atomic force microscopy. The measured {epsilon}(E) spectra reveal distinct structures at several interband critical points in the Brillouin zone of {beta}-Sn. These spectra are analyzed on the basis of a simplified model of the interband transitions, including the free-carrier absorption between the filled and empty electronic states. Dielectric-related optical constants, such as the complex refractive index, absorption coefficient, and normal-incidence reflectivity, of bulk {beta}-Sn films are also presented.

  6. Multiwavelength optical storage of diarylethene PMMA films

    NASA Astrophysics Data System (ADS)

    Guo, Haobo; Zhang, Fushi; Sun, Fan; Pu, Shouzhi; Zhou, Xinhong

    2003-04-01

    Current applied optical storage technologies are all based on the heat effect of the recording laser, i.e., heat-mode optical storage. In the present work, photon-mode optical storage using photochromic diarylethene materials was investigated. Two diarylethene molecules dispersed into PMMA together was used as storage material. The recording layer was spin-coated on a glass substrate with Al reflective layer. Two laser beams of 532 nm and 650 nm were used in recording and readout by simultaneously writing and reading, and the reading lasers detected signals with high S/N ratio. Multi-wavelength storage was realized with the diarylethene PMMA film.

  7. Nonlinear Optical Image Processing with Bacteriorhodopsin Films

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Deiss, Ron (Technical Monitor)

    1994-01-01

    The transmission properties of some bacteriorhodopsin film spatial light modulators are uniquely suited to allow nonlinear optical image processing operations to be applied to images with multiplicative noise characteristics. A logarithmic amplitude transmission feature of the film permits the conversion of multiplicative noise to additive noise, which may then be linearly filtered out in the Fourier plane of the transformed image. The bacteriorhodopsin film displays the logarithmic amplitude response for write beam intensities spanning a dynamic range greater than 2.0 orders of magnitude. We present experimental results demonstrating the principle and capability for several different image and noise situations, including deterministic noise and speckle. Using the bacteriorhodopsin film, we successfully filter out image noise from the transformed image that cannot be removed from the original image.

  8. Nonlinear Optical Image Processing with Bacteriorhodopsin Films

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Deiss, Ron (Technical Monitor)

    1994-01-01

    The transmission properties of some bacteriorhodopsin film spatial light modulators are uniquely suited to allow nonlinear optical image processing operations to be applied to images with multiplicative noise characteristics. A logarithmic amplitude transmission feature of the film permits the conversion of multiplicative noise to additive noise, which may then be linearly filtered out in the Fourier plane of the transformed image. The bacteriorhodopsin film displays the logarithmic amplitude response for write beam intensities spanning a dynamic range greater than 2.0 orders of magnitude. We present experimental results demonstrating the principle and capability for several different image and noise situations, including deterministic noise and speckle. Using the bacteriorhodopsin film, we successfully filter out image noise from the transformed image that cannot be removed from the original image.

  9. Optical properties of amorphous hydrogenated carbon films

    NASA Astrophysics Data System (ADS)

    Chen, Jing Qiu

    Carbon can be formed either as fully crystalline structures, such as diamond, graphite, and fullerene (C60). or as mostly amorphous structures, like amorphous hydrogenated carbon (a-C:H). A study was made of a-C:H films which had been deposited by plasma enhanced chemical vapor deposition (PECVD) using CH4, H2 and Ar (or N2 for doping) gas mixtures. Each film exhibits unique physical, optical and electronic properties dependent upon the specific deposition parameters. The study is intended to extend our understanding of the properties of a-C:H films. Samples prepared by James Johnson, similar to those used in his previous studies (using mainly 4 separate sets of deposition parameters), were evaluated along with other samples which were unique to this study. Film preparation parameters were varied to allow an examination of the effects induced through the variation of deposition power level, partial substitution of nitrogen for methane in the deposition process gasses and post-deposition thermal annealing. The film optical properties were evaluated using combination of non-destructive test methods, including Raman scattering, photoluminescence (PL), optical absorption and photoluminescence excitation (PLE) spectroscopies. Different PL responses at low temperature (6 K) were recorded for doped and/or annealed samples deriving from the main set of samples. Two new features at 564 and 637 nm of nitrogen doped films replaced the 597 and 703 nm of undoped films. For the first time, three Raman phonon peaks were observed in a nitrogen doped and annealed film. Additional FTIR data indicated that the third Raman phonon peak was associated with CH2 and CH3 bonding structures. The Raman scattering data contributed to an improved understanding of the two-phase (sp2, sp3) model developed by Robertson. Optical absorption measurements could only be obtained for the films deposited on fused quartz. All other measurements were made on films deposited on silicon, which is opaque in

  10. Thin Hydrogel Films for Optical Biosensor Applications

    PubMed Central

    Mateescu, Anca; Wang, Yi; Dostalek, Jakub; Jonas, Ulrich

    2012-01-01

    Hydrogel materials consisting of water-swollen polymer networks exhibit a large number of specific properties highly attractive for a variety of optical biosensor applications. This properties profile embraces the aqueous swelling medium as the basis of biocompatibility, non-fouling behavior, and being not cell toxic, while providing high optical quality and transparency. The present review focuses on some of the most interesting aspects of surface-attached hydrogel films as active binding matrices in optical biosensors based on surface plasmon resonance and optical waveguide mode spectroscopy. In particular, the chemical nature, specific properties, and applications of such hydrogel surface architectures for highly sensitive affinity biosensors based on evanescent wave optics are discussed. The specific class of responsive hydrogel systems, which can change their physical state in response to externally applied stimuli, have found large interest as sophisticated materials that provide a complex behavior to hydrogel-based sensing devices. PMID:24957962

  11. Optical Nonlinearity in DNA Films

    DTIC Science & Technology

    1989-06-28

    ordered water spines. 3. REFERENCES AND FOOTNOTES 1. "Counterion Effects on the Structure and Dynamics of Solid DNA" T. Weidlich , S.M. Lindsay, and A...Lee, J. Powell, T. Weidlich , C. DeMarco, G.D. Lewen, N.J. Tao and A. Rupprecht, Biopolymers 27, 1015-1043 (1988). 4. "Statistical Mechanics of the B...Oligonucleotide Crystals and Highly Crystalline Films of Calf Thymus DNA" T. Weidlich , S.M. Lindsay, S.A. Lee, N.J. Tao, G.D. Lewen, W.L. Peticolas, G.A. Thomas and

  12. Ultrathin hydrogel films for rapid optical biosensing.

    PubMed

    Zhang, Xi; Guan, Ying; Zhang, Yongjun

    2012-01-09

    Novel biosensors have been designed by reporting an analyte-induced (de)swelling of a stimuli-responsive hydrogel (usually in a form of thin film) with a suitable optical transducer. These simple, inexpensive hydrogel biosensors are highly desirable, however, their practical applications have been hindered, largely because of their slow response. Here we show that quick response hydrogel sensors can be designed from ultrathin hydrogel films. By the adoption of layer-by-layer assembly, a simple but versatile approach, glucose-sensitive hydrogel films with thickness on submicrometer or micrometer scale, which is 2 orders of magnitude thinner than films used in ordinary hydrogel sensors, can be facilely fabricated. The hydrogel films can not only respond to the variation in glucose concentration, but also report the event via the shift of Fabry-Perot fringes using the thin film itself as Fabry-Perot cavity. The response is linear and reversible. More importantly, the response is quite fast, making it possible to be used for continuous glucose monitoring.

  13. Design of Gradient Index Optical Thin Films

    NASA Astrophysics Data System (ADS)

    Druessel, Jeffrey J.

    Gradient index thin films provide greater flexibility for the design of optical coatings than the more conventional "layer" films. In addition, gradient index films have higher damage thresholds and better adhesion properties. In this dissertation I present an enhancement to the existing inverse Fourier transform gradient index design method, and develop a new optimal design method for gradient index films using a generalized Fourier series approach. The inverse Fourier transform method is modified to include use of the phase of the index profile as a variable in rugate filter design. Use of an optimal phase function in Fourier-based filter designs reduces the product of index contrast and thickness for desired reflectance spectra. The shape of the reflectance spectrum is recovered with greater fidelity by suppression of Gibbs oscillations and shifting of side-lobes into desired wavelength regions. A new method of gradient index thin film design using generalized Fourier series extends the domain of problems for which gradient index solutions can be found. The method is analogous to existing techniques for layer based coating design, but adds the flexibility of gradient index films. A subset of the coefficients of a generalized Fourier series representation of the gradient index of refraction profile are used as variables in a nonlinear constrained optimization formulation. The optimal values of the design coefficients are determined using a sequential quadratic programming algorithm. This method is particularly well suited for the design of coatings for laser applications, where only a few widely separated wavelength requirements exist. The generalized Fourier series method is extended to determine the minimum film thickness needed, as well as the index of refraction profile for the optimal film.

  14. Polydiacetylene thin films for nonlinear optical applications

    NASA Technical Reports Server (NTRS)

    Paley, Mark S.

    1993-01-01

    One very promising class of organic compounds for nonlinear optical (NLO) applications are polydiacetylenes, which are novel in that they are highly conjugated polymers which can also be crystalline. Polydiacetylenes offer several advantages over other organic materials: because of their highly conjugated electronic structures, they are capable of possessing large optical nonlinearities with fast response times; because they are crystalline, they can be highly ordered, which is essential for optimizing their NLO properties; and, last, because they are polymeric, they can be formed as thin films, which are useful for device fabrication. We have actively been carrying out ground-based research on several compounds of interest.

  15. Polydiacetylene thin films for nonlinear optical applications

    NASA Technical Reports Server (NTRS)

    Paley, Mark S.

    1993-01-01

    One very promising class of organic compounds for nonlinear optical (NLO) applications are polydiacetylenes, which are novel in that they are highly conjugated polymers which can also be crystalline. Polydiacetylenes offer several advantages over other organic materials: because of their highly conjugated electronic structures, they are capable of possessing large optical nonlinearities with fast response times; because they are crystalline, they can be highly ordered, which is essential for optimizing their NLO properties; and, last, because they are polymeric, they can be formed as thin films, which are useful for device fabrication. We have actively been carrying out ground-based research on several compounds of interest.

  16. Flexible parylene-film optical waveguide arrays

    NASA Astrophysics Data System (ADS)

    Yamagiwa, S.; Ishida, M.; Kawano, T.

    2015-08-01

    Modulation of neuronal activities by light [e.g., laser or light-emitting diode] using optogenetics is a powerful tool for studies on neuronal functions in a brain. Herein, flexible thin-film optical waveguide arrays based on a highly biocompatible material of parylene are reported. Parylene-C and -N thin layers with the different refractive indices form the clad and the core of the waveguide, respectively, and neural recording microelectrodes are integrated to record optical stimuli and electrical recordings simultaneously using the same alignment. Both theoretical and experimental investigations confirm that light intensities of more than 90% can propagate in a bent waveguide with a curvature radius of >5 mm. The proposed flexible thin-film waveguide arrays with microelectrodes can be used for numerous spherical bio-tissues, including brain and spinal cord samples.

  17. Unison micro-optic security film

    NASA Astrophysics Data System (ADS)

    Steenblik, Richard A.; Hurt, Mark J.

    2004-06-01

    Unison is a new class of highly counterfeit and simulation resistant micro-optic security films that provide a wide range of overt, unique, and highly visible three-dimensional and fluidic motion visual effects for currency, document, and product authentication by the general public. Unlike holograms, interference films, and diffractive OVDs, Unison incorporates micron-scale geometrical optic systems to create synthetic images that exhibit striking visual effects that are independent of illumination angle and collimation. Unison presents a pattern of visually dynamic, non-holographic, colored images that are seen against either a transparent or an opaque background. These images can be designed to either float above the surface, appear beneath the surface, or appear in the plane of the surface and to move in a counter-intuitive ortho-parallactic manner. Unison can be used as a laminate over print without obscuring it; the Unison images appear to move within, under, or over the print. Unison images can be viewed under all lighting conditions from any azimuthal angle and from a wide range of elevation angles. This new material is highly resistant to counterfeiting because it is an all-polymer multi-layer film that contains no metallized layers and its non-diffractive optical elements are based on proprietary origination, tooling, and manufacturing processes.

  18. Optical storage characters of bacteriorhodopsin molecule film

    NASA Astrophysics Data System (ADS)

    Chen, Feng; Yang, Qing; Wu, Hongcai; Hou, Xun

    2002-04-01

    The photochromic retinal protein bacteriorhodopsin (BR) is found in the cell membrane of Halobacterium salinarium. It is the key protein for photosynthetic growth of H.salinarium. BR shows an exceptional stability towards chemical, thermal, and photochemical degradation. The photochromic properties of Bacteriorhodopsin provide the possibility of application in optical information storage. Photoexcition of the O-state of BR, which has an all-trans confirmation, leads to a state with 9-cis configuration, which is thermally stable. The 9-cis containing photoproduct of the O-state was named P-state. It absorbs at 490 nm and can be photochemically reconverted to the initial state. We propose a system of optical information storage in a BR polymer film, which is a reversible optical data recording material and can be rewritten over 106 times without degradation of the film. A three-wavelength EDRAW (Erase Direct Read After Write) experiment was performed. The photoexcited P(490) state shows a permanent storage property confirmed by our contrast ratio experiments. The result of long-term information storage in BR films more than 1 year is obtained.

  19. Electrical and optical properties of carbon films

    NASA Astrophysics Data System (ADS)

    Kulkarni, Pranita

    Carbon and carbon-based materials, including graphite, diamond, and other thin-film structures, are being intensively researched for a wide range of electronic applications. A variety of graphitic, nano-structured carbon materials can be synthesized that have current or potential applications as thin-film transistors, photovoltaics, and supercapacitors. Diamond has been pursued for many years for electronics that can be used in extreme conditions, such as high temperature, high power, high frequency, and radiation environments. In this research study, electronic properties of diamond and graphitic films with crystallite or grain sizes in the nanometer range were investigated. The nano-structured graphitic carbon films were grown using a previously developed method based on the pyrolysis of poly(acrylonitrile) and poly(n-butyl acrylate) block copolymers (PAN-b-PBA). An important characteristic of these films is that the morphology (and therefore other properties) can be controlled by the compositions and processing of the starting block copolymers. Spherical, cylindrical, lamellar, and branched morphologies have been fabricated. The crystallite sizes, optical absorption, and morphology of PAN-b-PBA (containing 17.8% PAN) pyrolyzed between 400 and 600°C were determined and were compared to those derived by pyrolysis of PAN homopolymers at the same temperatures. Hall-effect measurements on pyrolyzed PAN-b-PBA films with spherical, cylindrical, and branched morphologies and homopolymer PAN films pyrolyzed at the same temperatures revealed that both PAN-b-PBA with different morphologies and PAN homopolymer-derived films had n-type conductivity; differences in carrier concentration and mobility values were correlated with the morphological differences of the films. Optical absorption measurements in the ultra-violet through visible wavelength range were also conducted on these films; measurements of the pseudo band-gaps and absorption coefficients were correlated with

  20. Surface analysis of the selective excimer laser patterning of a thin PEDOT:PSS film on flexible polymer films

    NASA Astrophysics Data System (ADS)

    Schaubroeck, David; De Smet, Jelle; Willems, Wouter; Cools, Pieter; De Geyter, Nathalie; Morent, Rino; De Smet, Herbert; Van Steenbeerge, Geert

    2016-07-01

    Fast patterning of highly conductive polymers like PEDOT:PSS (poly (3,4-ethylene dioxythiophene): polystyrene sulfonate) with lasers can contribute to the development of industrial production of liquid crystal displays on polymer foils. In this article, the selective UV laser patterning of a PEDOT:PSS film on flexible polymer films is investigated. Based on their optical properties, three polymer films are investigated: polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and cellulose triacetate (TAC). Ablation parameters for a 110 nm PEDOT:PSS film on these polymer films are optimized. A detailed study of the crater depth, topography and surface composition are provided using optical profilometry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The electrical insulation of the lines is measured and correlated to the crater analyses for different laser settings. Finally, potential ablation parameters for each of the polymer films are derived.

  1. Thermal conductivities of thin, sputtered optical films

    SciTech Connect

    Henager, C.H. Jr.; Pawlewicz, W.T.

    1991-05-01

    The normal component of the thin film thermal conductivity has been measured for the first time for several advanced sputtered optical materials. Included are data for single layers of boron nitride (BN), aluminum nitride (AIN), silicon aluminum nitride (Si-Al-N), silicon aluminum oxynitride (Si-Al-O-N), silicon carbide (SiC), and for dielectric-enhanced metal reflectors of the form Al(SiO{sub 2}/Si{sub 3}N{sub 4}){sup n} and Al(Al{sub 2}O{sub 3}/AIN){sup n}. Sputtered films of more conventional materials like SiO{sub 2}, Al{sub 2}O{sub 3}, Ta{sub 2}O{sub 5}, Ti, and Si have also been measured. The data show that thin film thermal conductivities are typically 10 to 100 times lower than conductivities for the same materials in bulk form. Structural disorder in the amorphous or very fine-grained films appears to account for most of the conductivity difference. Conclusive evidence for a film/substrate interface contribution is presented.

  2. Permanent laser conditioning of thin film optical materials

    DOEpatents

    Wolfe, C.R.; Kozlowski, M.R.; Campbell, J.H.; Staggs, M.; Rainer, F.

    1995-12-05

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold. 9 figs.

  3. Permanent laser conditioning of thin film optical materials

    DOEpatents

    Wolfe, C. Robert; Kozlowski, Mark R.; Campbell, John H.; Staggs, Michael; Rainer, Frank

    1995-01-01

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold.

  4. Optical bistability with film-coupled metasurfaces.

    PubMed

    Huang, Zhiqin; Baron, Alexandre; Larouche, Stéphane; Argyropoulos, Christos; Smith, David R

    2015-12-01

    Metasurfaces comprising arrays of film-coupled, nanopatch antennas are a promising platform for low-energy, all-optical switches. The large field enhancements that can be achieved in the dielectric spacer region between the nanopatch and the metallic substrate can substantially enhance optical nonlinear processes. Here we consider a dielectric material that exhibits an optical Kerr effect as the spacer layer and numerically calculate the optical bistability of a metasurface using the finite element method (FEM). We expect the proposed method to be highly accurate compared with other numerical approaches, such as those based on graphical post-processing techniques, because it self-consistently solves for both the spatial field distribution and the intensity-dependent refractive index distribution of the spacer layer. This method offers an alternative approach to finite-difference time-domain (FDTD) modeling. We use this numerical tool to design a metasurface optical switch and our optimized design exhibits exceptionally low switching intensity of 33  kW/cm2, corresponding to switching energy on the order of tens of attojoules per resonator, a value much smaller than those found for most devices reported in the literature. We propose our method as a tool for designing all-optical switches and modulators.

  5. Multiplexed Holographic Optical Data Storage In Thick Bacteriorhodopsin Films

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Timucin, Dogan A.; Gary, Charles K.; Ozcan, Meric; Smithey, Daniel T.; Crew, Marshall

    1998-01-01

    The optical data storage capacity of photochromic bacteriorhodopsin films is investigated by means of theoretical calculations, numerical simulations, and experimental measurements on sequential recording of angularly multiplexed diffraction gratings inside a thick D85N BR film.

  6. Multiplexed Holographic Optical Data Storage In Thick Bacteriorhodopsin Films

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Timucin, Dogan A.; Gary, Charles K.; Ozcan, Meric; Smithey, Daniel T.; Crew, Marshall

    1998-01-01

    The optical data storage capacity of photochromic bacteriorhodopsin films is investigated by means of theoretical calculations, numerical simulations, and experimental measurements on sequential recording of angularly multiplexed diffraction gratings inside a thick D85N BR film.

  7. Emittance Theory for Thin Film Selective Emitter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Lowe, Roland A.; Good, Brian S.

    1994-01-01

    Thin films of high temperature garnet materials such as yttrium aluminum garnet (YAG) doped with rare earths are currently being investigated as selective emitters. This paper presents a radiative transfer analysis of the thin film emitter. From this analysis the emitter efficiency and power density are calculated. Results based on measured extinction coefficients for erbium-YAG and holmium-YAG are presented. These results indicated that emitter efficiencies of 50 percent and power densities of several watts/sq cm are attainable at moderate temperatures (less than 1750 K).

  8. Biotin selective polymer nano-films

    PubMed Central

    2014-01-01

    Background The interaction between biotin and avidin is utilized in a wide range of assay and diagnostic systems. A robust material capable of binding biotin should offer scope in the development of reusable assay materials and biosensor recognition elements. Results Biotin-selective thin (3–5 nm) films have been fabricated on hexadecanethiol self assembled monolayer (SAM) coated Au/quartz resonators. The films were prepared based upon a molecular imprinting strategy where N,N'-methylenebisacrylamide and 2-acrylamido-2-methylpropanesulfonic acid were copolymerized and grafted to the SAM-coated surface in the presence of biotin methyl ester using photoinitiation with physisorbed benzophenone. The biotinyl moiety selectivity of the resonators efficiently differentiated biotinylated peptidic or carbohydrate structures from their native counterparts. Conclusions Molecularly imprinted ultra thin films can be used for the selective recognition of biotinylated structures in a quartz crystal microbalance sensing platform. These films are stable for periods of at least a month. This strategy should prove of interest for use in other sensing and assay systems. PMID:24655809

  9. Optical conductivity of topological insulator thin films

    SciTech Connect

    Li, L. L.; Xu, W.; Peeters, F. M.

    2015-05-07

    We present a detailed theoretical study on the optoelectronic properties of topological insulator thin film (TITFs). The k·p approach is employed to calculate the energy spectra and wave functions for both the bulk and surface states in the TITF. With these obtained results, the optical conductivities induced by different electronic transitions among the bulk and surface states are evaluated using the energy-balance equation derived from the Boltzmann equation. We find that for Bi{sub 2}Se{sub 3}-based TITFs, three characteristic regimes for the optical absorption can be observed. (i) In the low radiation frequency regime (photon energy ℏω<200 meV), the free-carrier absorption takes place due to intraband electronic transitions. An optical absorption window can be observed. (ii) In the intermediate radiation frequency regime (200<ℏω<300 meV), the optical absorption is induced mainly by interband electronic transitions from surface states in the valance band to surface states in the conduction band and an universal value σ{sub 0}=e{sup 2}/(8ℏ) for the optical conductivity can be obtained. (iii) In the high radiation frequency regime (ℏω>300 meV), the optical absorption can be achieved via interband electronic transitions from bulk and surface states in the valance band to bulk and surface states in the conduction band. A strong absorption peak can be observed. These interesting findings indicate that optical measurements can be applied to identify the energy regimes of bulk and surface states in the TITF.

  10. Robust, Thin Optical Films for Extreme Environments

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The environment of space presents scientists and engineers with the challenges of a harsh, unforgiving laboratory in which to conduct their scientific research. Solar astronomy and X-ray astronomy are two of the more challenging areas into which NASA scientists delve, as the optics for this high-tech work must be extremely sensitive and accurate, yet also be able to withstand the battering dished out by radiation, extreme temperature swings, and flying debris. Recent NASA work on this rugged equipment has led to the development of a strong, thin film for both space and laboratory use.

  11. Nonlinear optics of astaxanthin thin films

    NASA Astrophysics Data System (ADS)

    Esser, A.; Fisch, Herbert; Haas, Karl-Heinz; Haedicke, E.; Paust, J.; Schrof, Wolfgang; Ticktin, Anton

    1993-02-01

    Carotinoids exhibit large nonlinear optical properties due to their extended (pi) -electron system. Compared to other polyenes which show a broad distribution of conjugation lengths, carotinoids exhibit a well defined molecular structure, i.e. a well defined conjugation length. Therefore the carotinoid molecules can serve as model compounds to study the relationship between structure and nonlinear optical properties. In this paper the synthesis of four astaxanthins with C-numbers ranging from 30 to 60, their preparation into thin films, wavelength dispersive Third Harmonic Generation (THG) measurements and some molecular modelling calculations will be presented. Resonant (chi) (3) values reach 1.2(DOT)10-10 esu for C60 astaxanthin. In the nonresonant regime a figure of merit (chi) (3)/(alpha) of several 10-13 esu-cm is demonstrated.

  12. Thermally induced optical nonlinearity during transient heating of thin films

    SciTech Connect

    Chen, G. ); Tien, C.L. )

    1994-05-01

    This work studies the temperature field and the optical response of weakly absorbing thin films with thermally induced optical nonlinearity during picosecond to nanosecond pulsed-laser heating. A one-dimensional model is presented that examines the effects of the temperature dependent optical constants and the nonuniform absorption caused by interference. The energy equation is solved numerically, coupled with the matrix method in optical multilayer theory. Both cadmium sulfide (CdS) thin films and a zinc selenide (ZnSe) interference filter are considered. The computational results compare favorably with available experimental data on the ZnSe interference filter. This study shows that the transient temperature distributions in the films are highly nonuniform. Such nonuniformity yields Airy's formulae for calculating the thin-film reflectance and transmittance inapplicable. Applications of the work include optical bistability, localized change of the film structure, and measurement of the thermal diffusivity of thin films. 31 refs., 7 figs., 1 tab.

  13. Preparation of polymeric diacetylene thin films for nonlinear optical applications

    NASA Technical Reports Server (NTRS)

    Frazier, Donald O. (Inventor); Mcmanus, Samuel P. (Inventor); Paley, Mark S. (Inventor); Donovan, David N. (Inventor)

    1995-01-01

    A method for producing polymeric diacetylene thin films having desirable nonlinear optical characteristics has been achieved by producing amorphous diacetylene polymeric films by simultaneous polymerization of diacetylene monomers in solution and deposition of polymerized diacetylenes on to the surface of a transparent substrate through which ultraviolet light has been transmitted. These amorphous polydiacetylene films produced by photo-deposition from solution possess very high optical quality and exhibit large third order nonlinear optical susceptibilities, such properties being suitable for nonlinear optical devices such as waveguides and integrated optics.

  14. Optically Active Nanostructured ZnO Films.

    PubMed

    Duan, Yingying; Han, Lu; Zhang, Jialiang; Asahina, Shunsuke; Huang, Zhehao; Shi, Lin; Wang, Bo; Cao, Yuanyuan; Yao, Yuan; Ma, Liguo; Wang, Cui; Dukor, Rina K; Sun, Lu; Jiang, Chun; Tang, Zhiyong; Nafie, Laurence A; Che, Shunai

    2015-12-07

    Inorganic nanomaterials endowed with hierarchical chirality could open new horizons in physical theory and applications because of their fascinating properties. Here, we report chiral ZnO films coated on quartz substrates with a hierarchical nanostructure ranging from atomic to micrometer scale. Three levels of hierarchical chirality exist in the ZnO films: helical ZnO crystalline structures that form primary helically coiled nanoplates, secondary helical stacking of these nanoplates, and tertiary nanoscale circinate aggregates formed by several stacked nanoplates. These films exhibited optical activity (OA) at 380 nm and in the range of 200-800 nm and created circularly polarized luminescence centered at 510 nm and Raman OA at 50-1400 cm(-1) , which was attributed to electronic transitions, scattering, photoluminescent emission, and Raman scattering in a dissymmetric electric field. The unprecedented strong OA could be attributed to multiple light scattering and absorption-enhanced light harvesting in the hierarchical structures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. 36 CFR 704.1 - Films selected for inclusion in the National Film Registry.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Films selected for inclusion in the National Film Registry. 704.1 Section 704.1 Parks, Forests, and Public Property LIBRARY OF CONGRESS NATIONAL FILM REGISTRY OF THE LIBRARY OF CONGRESS § 704.1 Films selected for inclusion in the...

  16. 36 CFR 704.1 - Films selected for inclusion in the National Film Registry.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Films selected for inclusion in the National Film Registry. 704.1 Section 704.1 Parks, Forests, and Public Property LIBRARY OF CONGRESS NATIONAL FILM REGISTRY OF THE LIBRARY OF CONGRESS § 704.1 Films selected for inclusion in the...

  17. 36 CFR 704.1 - Films selected for inclusion in the National Film Registry.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Films selected for inclusion in the National Film Registry. 704.1 Section 704.1 Parks, Forests, and Public Property LIBRARY OF CONGRESS NATIONAL FILM REGISTRY OF THE LIBRARY OF CONGRESS § 704.1 Films selected for inclusion in the...

  18. 36 CFR 704.1 - Films selected for inclusion in the National Film Registry.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Films selected for inclusion in the National Film Registry. 704.1 Section 704.1 Parks, Forests, and Public Property LIBRARY OF CONGRESS NATIONAL FILM REGISTRY OF THE LIBRARY OF CONGRESS § 704.1 Films selected for inclusion in...

  19. Optical method for the determination of stress in thin films

    DOEpatents

    Maris, Humphrey J.

    1999-01-01

    A method and optical system is disclosed for measuring an amount of stress in a film layer disposed over a substrate. The method includes steps of: (A) applying a sequence of optical pump pulses to the film layer, individual ones of said optical pump pulses inducing a propagating strain pulse in the film layer, and for each of the optical pump pulses, applying at least one optical probe pulse, the optical probe pulses being applied with different time delays after the application of the corresponding optical probe pulses; (B) detecting variations in an intensity of a reflection of portions of the optical probe pulses, the variations being due at least in part to the propagation of the strain pulse in the film layer; (C) determining, from the detected intensity variations, a sound velocity in the film layer; and (D) calculating, using the determined sound velocity, the amount of stress in the film layer. In one embodiment of this invention the step of detecting measures a period of an oscillation in the intensity of the reflection of portions of the optical probe pulses, while in another embodiment the step of detecting measures a change in intensity of the reflection of portions of the optical probe pulses and determines a time at which the propagating strain pulse reflects from a boundary of the film layer.

  20. Optical method for the determination of stress in thin films

    DOEpatents

    Maris, H.J.

    1999-01-26

    A method and optical system is disclosed for measuring an amount of stress in a film layer disposed over a substrate. The method includes steps of: (A) applying a sequence of optical pump pulses to the film layer, individual ones of said optical pump pulses inducing a propagating strain pulse in the film layer, and for each of the optical pump pulses, applying at least one optical probe pulse, the optical probe pulses being applied with different time delays after the application of the corresponding optical probe pulses; (B) detecting variations in an intensity of a reflection of portions of the optical probe pulses, the variations being due at least in part to the propagation of the strain pulse in the film layer; (C) determining, from the detected intensity variations, a sound velocity in the film layer; and (D) calculating, using the determined sound velocity, the amount of stress in the film layer. In one embodiment of this invention the step of detecting measures a period of an oscillation in the intensity of the reflection of portions of the optical probe pulses, while in another embodiment the step of detecting measures a change in intensity of the reflection of portions of the optical probe pulses and determines a time at which the propagating strain pulse reflects from a boundary of the film layer. 16 figs.

  1. Optical readout of hydrogen storage in films of Au and Pd

    NASA Astrophysics Data System (ADS)

    Nishijima, Yoshiaki; Shimizu, Shogo; Kurihara, Keisuke; Hashimoto, Yoshikazu; Takahashi, Hajime; Balčytis, Armandas; Seniutinas, Gediminas; Okazaki, Shinji; Juodkazytė, Jurga; Iwasa, Takeshi; Taketsugu, Tetsuya; Tominaga, Yoriko; Juodkazis, Saulius

    2017-10-01

    For hydrogen sensor and storage applications, films of Au and Pd were (i) co-sputtered at different rates or (ii) deposited in a sequential layer-by-layer fashion on a cover glass. Peculiarities of hydrogen uptake and release were optically monitored using 1.3 micrometers wavelength light. Increase of optical transmission was observed for hydrogenated Pd-rich films of 10-30 nm thickness. Up to a three times slower hydrogen release took place as compared with the hydrogen uptake. Composition ratio of Au:Pd and thermal treatment of films provided control over the optical extinction changes and hydrogen uptake/release time constants. Higher uptake and release rates were observed in the annealed Au:Pd films as compared to those deposited at room temperature and were faster for the Au-richer films. Three main parameters relevant for sensors: sensitivity, selectivity, stability (reproducibility) are discussed together with the hydrogenation mechanism in Au:Pd alloys.

  2. Biochrome-reversing medium films for optical recording

    NASA Astrophysics Data System (ADS)

    Vsevolodov, N. N.; Ivanitskii, G. R.; Soskii, M. S.; Taranenko, V. B.

    1986-04-01

    The possibility of using photosensitive biological complexes as a photorecording material is demonstrated experimentally using bacteriorhodopsin as an example. The principal photoresponse characteristics of the bacteriorhodopsin films, referred to as BR biochrome films, are presented. It is shown that BR biochrome films can be used for bit mapping, polarization holograms and wavefront reversal recording, and studying polarization-induced changes and optical bistability effects.

  3. Optical conductivity of amorphous Ta and beta-Ta films

    NASA Technical Reports Server (NTRS)

    Nestell, J. E., Jr.; Scoles, K. J.; Christy, R. W.

    1982-01-01

    Tantalum films evaporated in high vacuum onto liquid-nitrogen-cooled substrates had an amorphous structure that persisted even after warming to room temperature. The optical conductivity (as well as the dc conductivity) of the amorphous films differed significantly from that of the bcc films.

  4. Depositing highly adhesive optical thin films on acrylic substrates.

    PubMed

    Takahashi, Tomoaki; Harada, Toshinori; Murotani, Hiroshi; Matumoto, Shigeharu

    2014-02-01

    Optical thin films are used to control the reflectance and transmittance of optical components. However, conventional deposition technologies applicable to organic (plastic) substrates typically result in weak adhesion. We overcame this problem by using vacuum deposition in combination with sputtering to directly deposit a SiO2 optical thin film onto an acrylic resin substrate. We observed neither yellowing nor deformation. The hardness of the film is 2H as measured by the pencil hardness test, indicating successful modulation of optical properties without sacrificing substrate hardness.

  5. Structural and Optical Properties of Nanoscale Galinobisuitite Thin Films

    PubMed Central

    Abd-Elkader, Omar H.; Deraz, N. M.

    2014-01-01

    Galinobisuitite thin films of (Bi2S3)(PbS) were prepared using the chemical bath deposition technique (CBD). Thin films were prepared by a modified chemical deposition process by allowing the triethanolamine (TEA) complex of Bi3+ and Pb2+ to react with S2− ions, which are released slowly by the dissociation of the thiourea (TU) solution. The films are polycrystalline and the average crystallite size is 35 nm. The composition of the films was measured using the atomic absorption spectroscopy (AAS) technique. The films are very adherent to the substrates. The crystal structure of Galinobisuitite thin films was calculated by using the X-ray diffraction (XRD) technique. The surface morphology and roughness of the films were studied using scanning electron microscopes (SEM), transmission electron microscopes (TEM) and stylus profilers respectively. The optical band gaps of the films were estimated from optical measurements. PMID:24473136

  6. Structural and optical properties of nanoscale Galinobisuitite thin films.

    PubMed

    Abd-Elkader, Omar H; Deraz, N M

    2014-01-27

    Galinobisuitite thin films of (Bi2S3)(PbS) were prepared using the chemical bath deposition technique (CBD). Thin films were prepared by a modified chemical deposition process by allowing the triethanolamine (TEA) complex of Bi(3+) and Pb(2+) to react with S(2)- ions, which are released slowly by the dissociation of the thiourea (TU) solution. The films are polycrystalline and the average crystallite size is 35 nm. The composition of the films was measured using the atomic absorption spectroscopy (AAS) technique. The films are very adherent to the substrates. The crystal structure of Galinobisuitite thin films was calculated by using the X-ray diffraction (XRD) technique. The surface morphology and roughness of the films were studied using scanning electron microscopes (SEM), transmission electron microscopes (TEM) and stylus profilers respectively. The optical band gaps of the films were estimated from optical measurements.

  7. Optical characterization of copper indium gallium diselenide thin films

    NASA Astrophysics Data System (ADS)

    Hebert, Damon

    Cu(In,Ga)Se2 (CIGS) and its alloys are the leading choice for thin film photovoltaic absorber layers due to their high performance in devices, low degradation, high optical absorption coefficient and high tolerance to off-stoichiometry and intrinsic defects. Film conductivity and recombination losses are controlled by intrinsic point defect concentrations, especially in the near-surface space-charge region of the heterojunction. Despite the amount of research already performed on CIGS alloys, their optoelectronic properties, defect chemistry and recombination mechanisms are still poorly understood. The focus of this dissertation is to optically characterize a selection of CIGS absorber layers fabricated by various techniques in order to better understand the radiative emission and defect physics. This work aims to identify the defects responsible for recombination and their relation to grain boundaries and band edge fluctuations, which limit device performance. This study used photoluminescence (PL) spectroscopy, photoluminescence excitation (PLE) spectroscopy, and cathodoluminescence (CL) to study radiative emissions from a variety of Cu-poor CIGS thin films. Three general types of CIGS films were analyzed. Polycrystalline layers deposited on Mo-coated soda lime glass, polycrystalline layers deposited on metal foil, and epitaxial films grown on (100) and (111) GaAs were analyzed in this work. This work concludes that the donor-acceptor pair recombination model used in most interpretations of CIGS emission should be replaced with a model that accounts for high compensation and band edge fluctuations, which is shown to be undoubtedly the case in Cu-poor CIGS. Within this model, the most commonly observed emissions were explained as free-to-bound types, specifically iii band-to-impurity (BI) and tail-to-impurity (TI) types. Band tail width was measured by PLE. A correlation was established between band tail width and device efficiency. CIGS absorber layers that

  8. Large-area graphene films by simple solution casting of edge-selectively functionalized graphite.

    PubMed

    Bae, Seo-Yoon; Jeon, In-Yup; Yang, Jieun; Park, Noejung; Shin, Hyeon Suk; Park, Sungjin; Ruoff, Rodney S; Dai, Liming; Baek, Jong-Beom

    2011-06-28

    We report edge-selective functionalization of graphite (EFG) for the production of large-area uniform graphene films by simply solution-casting EFG dispersions in dichloromethane on silicon oxide substrates, followed by annealing. The resultant graphene films show ambipolar transport properties with sheet resistances of 0.52-3.11 kΩ/sq at 63-90% optical transmittance. EFG allows solution processing methods for the scalable production of electrically conductive, optically transparent, and mechanically robust flexible graphene films for use in practice.

  9. Optical information storage of bacteriorhodopsin molecule film

    NASA Astrophysics Data System (ADS)

    Chen, Feng; Li, Baofang; Hou, Xun; Li, XingChang; Jiang, Long; Sanio, Markus; Hampp, Norbert A.

    2000-11-01

    The photochromic retinal protein bacteriorhodopsin (BR) is found in the cell membrane of Halobacterium salinarium. It is the key protein for photosynthetic growth of H.salinarium. BR shows an exceptional stability towards chemical, thermal, and photochemical degradation. In this paper, we propose a system of optical information storage in a BR polymer film. A three- wavelength EDRAW (Erase Direct Read After Write) experiment was performed. The photoexcited P(490) state shows a permanent storage property confirmed by our contrast ratio experiments. We have performed the reversible operations of 'write' and 'erase' with the BR polymer film over hundreds of cycles in our experiments. The readout contrast ratio is very sensitive to the intensity and wavelength of probe beam and the recorded data can be readout from 530 to approximately 630 nm with different contrast ratio. Within the range of 570 to approximately 600 nmm, the better contrast ratio can be obtained. Considering the erasing effect for the reason of absorption of P state, both higher contrast ratio and nondestructive reading can be realized by using 594 nm as the readout wavelength. The experimental result such BR material is very suitable for long-term photochromic information storage.

  10. Polydimethylsiloxane thin film characterization using all-optical photoacoustic mechanism.

    PubMed

    Zou, Xiaotian; Wu, Nan; Tian, Ye; Zhang, Yang; Wang, Xingwei

    2013-09-01

    This paper presents a nondestructive ultrasound testing method for characterization of the resonant frequencies of polydimethylsiloxane (PDMS) thin film by using a miniature fiber optic photoacoustic (PA) probe. The PA probe was fabricated with an optical fiber and a synthesized gold nanocomposite. During the experiment, a cured PDMS thin film with a thickness of 220 μm was immersed into a water medium using a custom-designed holder to clamp the film. An acoustic pulse was generated by the PA probe and propagated through the water media to excite the fixed film. A fiber optic pressure sensor based on the Fabry-Perot principle was used to collect the excited acoustic signals on the other side of the film. The acquired response of the acoustic pulse was used to compute the resonant frequencies of the PDMS thin film based on a deconvolution method.

  11. The Effect of Radiation on Selected Photographic Film

    NASA Technical Reports Server (NTRS)

    Slater, Richard; Kinard, John; Firsov, Ivan

    2000-01-01

    We conducted this film test to evaluate several manufacturers' photographic films for their ability to acquire imagery on the International Space Station. We selected 25 motion picture, photographic slide, and negative films from three different film manufacturers. We based this selection on the fact that their films ranked highest in other similar film tests, and on their general acceptance by the international community. This test differed from previous tests because the entire evaluation process leading up to the final selection was based on information derived after the original flight film was scanned to a digital file. Previously conducted tests were evaluated entirely based on 8 x 10s that were produced from the film either directly or through the internegative process. This new evaluation procedure provided accurate quantitative data on granularity and contrast from the digital data. This test did not try to define which film was best visually. This is too often based on personal preference. However, the test results did group the films by good, marginal, and unacceptable. We developed, and included in this report, a template containing quantitative, graphical, and visual information for each film. These templates should be sufficient for comparing the different films tested and subsequently selecting a film or films to be used for experiments and general documentation on the International Space Station.

  12. Review on optical fiber sensors with sensitive thin films

    NASA Astrophysics Data System (ADS)

    Yang, Minghong; Dai, Jixiang

    2012-03-01

    The combination of fiber optics with nano-structure technologies and sensitive thin films offers great potential for the realization of novel sensor concepts. Miniatured optical fiber sensors with thin films as sensitive elements could open new fields for optical fiber sensor applications. Thin films work as sensitive elements and transducer to get response and feedback from environments, in which optical fibers are employed to work as signal carrier. This article presents some research work conducted at the National Engineering Laboratory for Optical Fiber Sensing Technologies in recent years. Concrete examples are: Pd/WO3 co-sputtered coating as sensing material for optical hydrogen sensors shows robust mechanical stability and meanwhile good sensing performance; TbDyFe magnetostrictive coating directly deposited on fiber Bragg grating (FBG) demonstrates its possibility of miniature optical magnetic field/current sensors, and 40-pm shift of the FBG wavelength happens at a magnetic field order of 50 mT.

  13. Waveguide refractometry as a probe of thin film optical uniformity

    SciTech Connect

    Potter, Jr. B.G.; Dimos, D.; Sinclair, M.B.

    1997-02-01

    Optical inhomogeneities through the thickness of a sol-gel-derived, spin-coated Pb(Zr,Ti)O{sub 3} (PZT) thin film have been evaluated using prism-coupled waveguide refractometry. Unusual waveguide coupling angle behavior has been treated using a multilayer model to describe the optical characteristics of the film. Waveguide refractometry measurements, performed after incremental reductions in film thickness, were used to develop a consistent model for optical inhomogeneity through the film thickness. Specifically, a thin film layer model, consisting of alternating layers of high and low refractive index material, was found to accurately predict irregularities in transverse-electric (TE) mode coupling angles exhibited by the film. This layer structure has a spatial periodicity that is consistent with the positions of the upper film surface at intermediate firings during film synthesis. The correlation emphasizes the impact of the multistep thin-film deposition approach on the optical characteristics of the resulting thin film. {copyright} {ital 1997 Materials Research Society.}

  14. Dual Ion Beam Deposition Of Diamond Films On Optical Elements

    NASA Astrophysics Data System (ADS)

    Deutchman, Arnold H.; Partyka, Robert J.; Lewis, J. C.

    1990-01-01

    Diamond film deposition processes are of great interest because of their potential use for the formation of both protective as well as anti-reflective coatings on the surfaces of optical elements. Conventional plasma-assisted chemical vapor deposition diamond coating processes are not ideal for use on optical components because of the high processing temperatures required, and difficulties faced in nucleating films on most optical substrate materials. A unique dual ion beam deposition technique has been developed which now makes possible deposition of diamond films on a wide variety of optical elements. The new DIOND process operates at temperatures below 150 aegrees Farenheit, and has been used to nucleate and grow both diamondlike carbon and diamond films on a wide variety of optical :taterials including borosilicate glass, quartz glass, plastic, ZnS, ZnSe, Si, and Ge.

  15. Selectively deuterated and optically active cyclic ethers

    SciTech Connect

    Kawakami, Y.; Asai, T.; Umeyama, K.; Yamashita, Y.

    1982-08-27

    The synthesis of selectively deuterated epihalohydrins (F, Cl, Br, I) and 3,3-bis(chloromethyl)-d/sub 2/)oxetane and some observations on the stereochemistry of each transformation are reported. Further, the synthesis of optically active epihalohydrins, especially the optically active epifluorohydrin, from (S)-glycerol 1,2-acetonide ((S)-2), using mainly KX-18-CR-6 (X = F, Br, I), is reported. This is the first report on the synthesis of optically active epifluorohydrin. The direct halogenation of the presynthesized optically active epichlorohydrin with the same reagents gave the racemized products. The selectively deuterated or optically active compounds reported herein are expected to find a variety of uses in organic chemistry.

  16. Passive optical element with selective angular reflection

    SciTech Connect

    Tremblay, C.; Rheault, F.; Boulay, R.; Tremblay, R.

    1987-02-01

    This work is related to the development of passive selective transmission materials that will contribute to regularize the solar thermal gain. We propose an original solution to the problem of seasonal control of energetic input into buildings through windows. A passive optical element with selective angular reflection is used to solve this problem. This optical element allows sunlight to enter windows during the fall and winter, whereas, owing to the different astronomical path of the sun, it stops and rejects direct sunlight by means of the optical effect called total internal reflection (TIR) during the central spring-Summer period. The purpose of this paper is to describe the optical element in some detail, to develop the principal design equations, and give the results of the optimization of optical and geometrical parameters.

  17. Passive optical element with selective angular reflection.

    PubMed

    Tremblay, C; Rheault, F; Boulay, R; Tremblay, R

    1987-02-01

    This work is related to the development of passive selective transmission materials that will contribute to regularize the solar thermal gain. We propose an original solution to the problem of seasonal control of energetic input into buildings through windows. A passive optical element with selective angular reflection is used to solve this problem. This optical element allows sunlight to enter windows during the fall and winter, whereas, owing to the different astronomical path of the sun, it stops and rejects direct sunlight by means of the optical effect called total internal reflection (TIR) during the central spring-summer period. The purpose of this paper is to describe the optical element in some detail, to develop the principal design equations, and give the results of the optimization of optical and geometrical parameters.

  18. Oriented niobate ferroelectric thin films for electrical and optical devices

    DOEpatents

    Wessels, Bruce W.; Nystrom, Michael J.

    2001-01-01

    Sr.sub.x Ba.sub.1-x Nb.sub.2 O.sub.6, where x is greater than 0.25 and less than 0.75, and KNbO.sub.3 ferroelectric thin films metalorganic chemical vapor deposited on amorphous or cyrstalline substrate surfaces to provide a crystal axis of the film exhibiting a high dielectric susceptibility, electro-optic coefficient, and/or nonlinear optic coefficient oriented preferentially in a direction relative to a crystalline or amorphous substrate surface. Such films can be used in electronic, electro-optic, and frequency doubling components.

  19. Analytical theory and method for longitudinal magneto-optical Kerr effect of optically anisotropic magnetic film

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Lian, Jie; Li, Ping; Xu, XiJin; Li, MengMeng

    2017-01-01

    The Fresnel equations are solved to analyze the reflection and propagation properties of the ordinary and extraordinary light of the optically anisotropic magnetic film. Using the boundary and propagation matrix, the longitudinal magneto-optical Kerr rotation expression is derived. After that, simulations are performed on optically anisotropic and isotropic Co/SiO2 film. Results show that for Co material in the thin-film limit, the anisotropic Co can provide larger max rotations than the isotropic Co in the visible region. This is because that the refractive index discrepancy of optically anisotropic Co film reduces the Fresnel reflective coefficient rpp, which improves the Kerr rotation. This makes the optically anisotropic Co film more effective in magneto optical sensor design and device fabrication.

  20. Novel optical sensing film based on a functional nonwoven nanofibre mat for an easy, fast and highly selective and sensitive detection of tryptamine in beer.

    PubMed

    Ramon-Marquez, Teresa; Medina-Castillo, Antonio L; Fernandez-Gutierrez, Alberto; Fernandez-Sanchez, Jorge F

    2016-05-15

    In this paper, the combination of Solid Surface-Room Temperature Phosphorescence (SS-RTP) and nanotechnology has led to a new approach in the detection of biogenic amines in complex matrices. This novel approach allows, for the first time, the direct determination of the concentration of tryptamine in beers. The novelty of the proposed optical sensor resides in its simplicity, rapidity, absence of complex chromatographic separation, sample clean-up, preconcentration, and derivatization protocols. Therefore, this novel methodology simplifies and reduces considerably the time and cost of the analysis, resolving the two major problems of the determination of tryptamine in beer up to now: low sensitivity and matrix effects. The proposed sensor is based on a novel white, uncharged, and non-luminescent functional nonwoven nanofibre mat (Tiss®-Link) formed by hydrophilic nanofibres of 300 nm of diameter functionalized with a high concentration of active vinyl groups (330 µmol g(-1)). It is used to carry out a kinetically controlled covalent immobilisation of tryptamine via Michael type-reaction. The transduction of the sensor is phosphorescence; the covalently immobilized tryptamine is quantified by SS-RTP, obtaining a detection limit of 6 ng mL(-1) with short response times (15 min). The applicability of the sensor was demonstrated by analysing tryptamine in 10 different varieties of beers, obtaining recovery percentages close to 100%.

  1. Iron nanoparticles embedded in carbon films: structural and optical properties

    NASA Astrophysics Data System (ADS)

    Mashayekhi, Fatemeh; Shafiekhani, Azizollah; Sebt, Seyed Ali

    2016-06-01

    In the present work amorphous hydrogenated carbon films with sputtered iron nanoparticles (Fe NPs @ a-C:H) were deposited by co-deposition of RF-sputtering and RF-plasma enhanced chemical vapor deposition methods using acetylene gas and iron target on quartz and silicon substrates. Samples were prepared in different initial pressures and during constant deposition time. The crystalline structure of Fe NPs @ a-C:H was studied using X-ray diffraction and selected area electron diffraction patterns. The X-ray photoelectron spectroscopy analysis presents that increasing the initial pressure decreases the atomic ratio of Fe/C and the sp3-hybridized carbon content in prepared samples. The transmission electron microscope image shows the encapsulated Fe NPs in carbon films. The optical properties and localized surface plasmon resonance (LSPR) of samples were studied using UV-visible spectrophotometry, which is shown that increasing of Fe content decreases the intensity of LSPR peak and increases the optical band gap.

  2. Structural and optical properties of molybdenum trioxide thin films

    SciTech Connect

    Bhatia, Shally; Khanna, Atul

    2015-06-24

    Thermal evaporation technique was used to prepare thin films of MoO{sub 3}. X-ray diffraction measurements found that as-deposited films of MoO{sub 3} were amorphous which crystallized to orthorhombic phase on annealing at 623K for 1h in air. The optical band gap of the films decreases from 3.1eV to 1.7eV upon crystallization. Short range structure of the as deposited films and annealed films were studied by Raman spectroscopy and it consisted of MoO{sub 6} units.

  3. Optical properties of sol-gel-derived PZT thin films

    NASA Astrophysics Data System (ADS)

    Teowee, Gimtong T.; Boulton, J. M.; Motakef, Sharnaz; Uhlmann, Donald R.; Zelinski, Brian J.; Zanoni, Raymond; Moon, M.

    1992-12-01

    A series of sol-gel derived PT-based films, including PT, PZ, PZT, PLT, PLZ and PLZT, was prepared on platinized Si, fused SiO2 and Corning 7059 substrates. These films were fired at 400 - 700 C for 30 mins. The phase assembly and development were dependent on the precursor chemistries, processing and choice of substrates. The presence of Zr impacted significantly on the crystallization behavior, PbO loss and cracking behavior of the films. Crystallization was severely retarded, especially in Zr-containing PZT films when deposited on amorphous substrates compared to crystalline Pt substrates. Amorphous and crystalline PZT films can be utilized for passive and active optical applications. Waveguiding was achieved in an amorphous PZT 53/47 and a crystalline PLT 28 films and gave attenuation losses of 1.0 and 1.4 dB/cm respectively which represent the lowest values reported to date. The optical properties of the films were investigated using ellipsometry, UV-VIS transmission spectroscopy and waveguide loss measurements. Depending on composition and processing conditions, PZT films (2500 A thick) with refractive indices of 1.60 to 2.33 and absorption edges of 2900 - 3100 A can be obtained. It was ascertained that the resulting interfacial reaction layers between the films and substrates affected considerably the optical properties of thinner films (< 2000 A).

  4. Optical characterization of gold coated over nanostructured alumina films

    NASA Astrophysics Data System (ADS)

    Aslan, Mustafa M.

    2014-02-01

    The gold coated over nanostructured alumina (GCON-A) films were investigated for layers' thicknesses and optical properties between 400 and 800 nm wavelength. First GCON-A films were fabricated in three steps: atomic layer deposition of alumina, hot water treatment, and gold deposition. Then, polarization maintained angular reflectance measurements were taken with a spectroscopic ellipsometry. Layer thicknesses, effective refractive indices, and absorption coefficients of films were determined through regression analysis on the ellipsometry data. To investigate the optical properties of the GCON-A films further, reflection measurements were taken by the visible spectroscopy. All these results verify that it is feasible to tune optical properties of the GCON-A films.

  5. Enhanced optical constants of nanocrystalline yttrium oxide thin films

    SciTech Connect

    Ramana, C. V.; Mudavakkat, V. H.; Bharathi, K. Kamala; Atuchin, V. V.; Pokrovsky, L. D.; Kruchinin, V. N.

    2011-01-17

    Yttrium oxide (Y{sub 2}O{sub 3}) films with an average crystallite-size (L) ranging from 5 to 40 nm were grown by sputter-deposition onto Si(100) substrates. The optical properties of grown Y{sub 2}O{sub 3} films were evaluated using spectroscopic ellipsometry measurements. The size-effects were significant on the optical constants and their dispersion profiles of Y{sub 2}O{sub 3} films. A significant enhancement in the index of refraction (n) is observed in well-defined Y{sub 2}O{sub 3} nanocrystalline films compared to that of amorphous Y{sub 2}O{sub 3}. A direct, linear L-n relationship found for Y{sub 2}O{sub 3} films suggests that tuning optical properties for desired applications can be achieved by controlling the size at the nanoscale dimensions.

  6. Optical sensors and multisensor arrays containing thin film electroluminescent devices

    DOEpatents

    Aylott, Jonathan W.; Chen-Esterlit, Zoe; Friedl, Jon H.; Kopelman, Raoul; Savvateev, Vadim N.; Shinar, Joseph

    2001-12-18

    Optical sensor, probe and array devices for detecting chemical biological, and physical analytes. The devices include an analyte-sensitive layer optically coupled to a thin film electroluminescent layer which activates the analyte-sensitive layer to provide an optical response. The optical response varies depending upon the presence of an analyte and is detected by a photodetector and analyzed to determine the properties of the analyte.

  7. An optical reflected device using a molecularly imprinted polymer film sensor.

    PubMed

    Wu, Nan; Feng, Liang; Tan, Yiyong; Hu, Jiming

    2009-10-19

    A novel and highly selective optical sensor with molecularly imprinted polymer (MIP) film was fabricated and investigated. The optical sensor head employing a medium finesse molecularly imprinted polymer film has been fabricated and characterised. A blank polymer and formaldehyde imprinted polymer were using methacrylic acid as the functional monomer and the ethylene glycol dimethacrylate as a crosslinker. The transduction mechanism is discussed based on the changes of optical intensity of molecularly imprinted polymer film acting as an optical reflected sensor. Template molecules, which diffused into MIP, could cause film density, and refractive index change, and then induce measurable optical reflective intensity shifts. Based on the reflective intensity shifts, an optical reflection detection of formaldehyde was achieved by illuminating MIP with a laser beam. For the same MIP, the reflective intensity shift was proportional to the amount of template molecule. This optical sensor, based on an artificial recognition system, demonstrates long-time stability and resistance to harsh chemical environments. As the research moves forward gradually, we establish the possibilities of quantitative analysis primly, setting the groundwork to the synthesis of the molecular imprinted optical fiber sensor. The techniques show good reproducibility and sensitivity and will be of significant interest to the MIP community.

  8. Optical reflectivity improvement by upgrading metallic glass film quality

    SciTech Connect

    Wang, W. H.; Hsu, J. H.; Huang, J. C.

    2013-10-14

    The effects of atomic-defect and free-volume amounts of metallic glassy film on the optical reflectivity and mechanical properties of the sputtered metallic glass thin films are explored. With a lower Ar working pressure and the proper post-annealing at temperatures slightly lower than the glass-transition temperature T{sub g}, film free volumes and defects would reduce, resulting in better atomic bonding and higher film hardness/modulus, which in turn leads to lower electric resistivity and higher optical reflectivity. Annealing above T{sub g} would induce crystalline structure which would lead to competition with the optical transition of the Drude free electrons and hinder the optical reflectivity in the visible range.

  9. 36 CFR § 704.1 - Films selected for inclusion in the National Film Registry.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Films selected for inclusion in the National Film Registry. § 704.1 Section § 704.1 Parks, Forests, and Public Property LIBRARY OF CONGRESS NATIONAL FILM REGISTRY OF THE LIBRARY OF CONGRESS § 704.1 Films selected for inclusion in...

  10. Extraordinary optical transmission in nanopatterned ultrathin metal films without holes

    SciTech Connect

    Peer, Akshit; Biswas, Rana

    2016-02-01

    In this study, we experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate exhibits extraordinary optical transmission, even though no holes were etched in the film. Our film synthesis started by nanoimprinting a periodic array of nanocups with a period of ~750 nm on a polystyrene film over a glass substrate. A thin non-conformal gold film was sputter-deposited on the polystyrene by angle-directed deposition. The gold film was continuous with spatial thickness variation, the film being thinnest at the bottom of the nanocup. Measurements revealed an extraordinary transmission peak at a wavelength just smaller than the period, with an enhancement of ~2.5 compared to the classically expected value. Scattering matrix simulations model well the transmission and reflectance measurements when an ultrathin gold layer (~5 nm), smaller than the skin depth is retained at the bottom of the nanocups. Electric field intensities are enhanced by >100 within the nanocup, and ~40 in the ultrathin gold layer causing transmission through it. We show a wavelength red-shift of ~30 nm in the extraordinary transmission peak when the nanocups are coated with a thin film of a few nanometers, which can be utilized for biosensing. The continuous corrugated metal films are far simpler structures to observe extraordinary transmission, circumventing the difficult process of etching the metal film. Such continuous metal films with ultrathin regions are simple platforms for non-linear optics, plasmonics, and biological and chemical sensing.

  11. Extraordinary optical transmission in nanopatterned ultrathin metal films without holes

    DOE PAGES

    Peer, Akshit; Biswas, Rana

    2016-02-01

    In this study, we experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate exhibits extraordinary optical transmission, even though no holes were etched in the film. Our film synthesis started by nanoimprinting a periodic array of nanocups with a period of ~750 nm on a polystyrene film over a glass substrate. A thin non-conformal gold film was sputter-deposited on the polystyrene by angle-directed deposition. The gold film was continuous with spatial thickness variation, the film being thinnest at the bottom of the nanocup. Measurements revealed an extraordinary transmission peak at a wavelength just smaller thanmore » the period, with an enhancement of ~2.5 compared to the classically expected value. Scattering matrix simulations model well the transmission and reflectance measurements when an ultrathin gold layer (~5 nm), smaller than the skin depth is retained at the bottom of the nanocups. Electric field intensities are enhanced by >100 within the nanocup, and ~40 in the ultrathin gold layer causing transmission through it. We show a wavelength red-shift of ~30 nm in the extraordinary transmission peak when the nanocups are coated with a thin film of a few nanometers, which can be utilized for biosensing. The continuous corrugated metal films are far simpler structures to observe extraordinary transmission, circumventing the difficult process of etching the metal film. Such continuous metal films with ultrathin regions are simple platforms for non-linear optics, plasmonics, and biological and chemical sensing.« less

  12. Optical isolator based on mode conversion in magnetic garnet films.

    PubMed

    Hemme, H; Dötsch, H; Menzler, H P

    1987-09-15

    Calculations are presented describing a novel optical isolator which works by complete TE(0)-TM(0) mode conversion in magnetic garnet films caused by stress-induced optical anisotropy (50%) and by Faraday rotation (50%). These conversions take place along two different, perpendicular light paths in the same crystal that are connected by an integrated mirror. Possible tolerances of the film parameters are given so that a 30-dB isolation is still guaranteed.

  13. Magneto-optical activity in organic thin film materials

    NASA Astrophysics Data System (ADS)

    Vleugels, Rick; de Vega, Laura; Brullot, Ward; Verbiest, Thierry; Gómez-Lor, Berta; Gutierrez-Puebla, Enrique; Hennrich, Gunther

    2016-12-01

    A series of CF3-capped phenylacetylenes with varying symmetry is obtained by a conventional palladium-catalyzed cross-coupling protocol. The phenylacetylene targets form thin films both, liquid crystalline (LC) and crystalline in nature depending on their molecular structure. The magneto-optical activity of the resulting organic material is extraordinarily high as proved by Faraday rotation spectroscopy on thin film devices.

  14. Optical analysis methods for material films condensed on cryogenic surfaces of spacecraft

    NASA Astrophysics Data System (ADS)

    Palmer, K. F.; Williams, M. Z.; Budde, B. A.; Bertrand, W. T.

    1994-08-01

    Exhaust gases from rocket motors and outgassing products of spacecraft materials can migrate, in a space environment, to other surfaces of the spacecraft and affect their functions. Cryogenically cooled optical systems are particularly vulnerable to these contaminants as are thermal control surfaces and solar cells. One of the goals of the contamination program at AEDC (Arnold Encineering Development Center) is to predict the optical effects of contaminant layers on optical systems from laboratory measurements of the optical indices, n and k, of contaminant materials. Because the cloud of contaminant molecules, which eventually form a condensate, contain a mixture of molecular species, researchers are seeking ways to predict the optical properties of films composed of constituents using the known properties of each constituent. In this report, the authors examine the physics which describe the optical properties of thin films composed of mixtures of constituents. Examples of the analysis methods are presented for thin films composed of mixtures using AEDC data on 20K thin films of simple molecules and 80K films condensed from the outgassing products of selected spacecraft materials.

  15. Optically Transparent Ferromagnetic Nanogranular Films with Tunable Transmittance

    NASA Astrophysics Data System (ADS)

    Kobayashi, Nobukiyo; Masumoto, Hiroshi; Takahashi, Saburo; Maekawa, Sadamichi

    2016-09-01

    Developing optically transparent magnets at room temperature is an important challenge. They would bring many innovations to various industries, not only for electronic and magnetic devices but also for optical applications. Here we introduce FeCo-(Al-fluoride) nanogranular films exhibiting ferromagnetic properties with high optical transparency in the visible light region. These films have a nanocomposite structure, in which nanometer-sized FeCo ferromagnetic granules are dispersed in an Al-fluoride crystallized matrix. The optical transmittance of these films is controlled by changing the magnetization. This is a new type of magneto-optical effect and is explained by spin-dependent charge oscillation between ferromagnetic granules due to quantum-mechanical tunneling.

  16. Optically Transparent Ferromagnetic Nanogranular Films with Tunable Transmittance

    PubMed Central

    Kobayashi, Nobukiyo; Masumoto, Hiroshi; Takahashi, Saburo; Maekawa, Sadamichi

    2016-01-01

    Developing optically transparent magnets at room temperature is an important challenge. They would bring many innovations to various industries, not only for electronic and magnetic devices but also for optical applications. Here we introduce FeCo-(Al-fluoride) nanogranular films exhibiting ferromagnetic properties with high optical transparency in the visible light region. These films have a nanocomposite structure, in which nanometer-sized FeCo ferromagnetic granules are dispersed in an Al-fluoride crystallized matrix. The optical transmittance of these films is controlled by changing the magnetization. This is a new type of magneto-optical effect and is explained by spin-dependent charge oscillation between ferromagnetic granules due to quantum-mechanical tunneling. PMID:27677710

  17. Thick optical films for the conduction of optical and infrared radiation

    SciTech Connect

    Bain, C.N.; Gordon, B.A.; Knasel, T.M.; Malinowski, R.L.

    1981-01-01

    Experimental results are presented for the characteristics of thick optical films, which can be used to direct and conduct optical and IR radiation, for the case of light concentration onto solar cells. Incident light is trapped within a thin, flat sheet of transparent material by a diffuse selective surface on the back of the transparent layer, and so directed that total internal reflection occurs, with some of the captured light finding its way back to the photovoltaic cells attached to the back of the layer. A Monte Carlo computer model is used to analyze this system, whose achievable gain depends on layer thickness, trapping material refraction index, and solar cell shape and size. Results indicate that gains of a factor of two in power output are obtainable for the case of sparsely-packed solar cell arrays and lower factors for more densely-packed arrays.

  18. Oriented niobate ferroelectric thin films for electrical and optical devices and method of making such films

    DOEpatents

    Wessels, B.W.; Nystrom, M.J.

    1998-05-19

    Sr{sub x}Ba{sub 1{minus}x}Nb{sub 2}O{sub 6}, where x is greater than 0.25 and less than 0.75, and KNbO{sub 3} ferroelectric thin films metalorganic chemical vapor deposited on amorphous or crystalline substrate surfaces to provide a crystal axis of the film exhibiting a high dielectric susceptibility, electro-optic coefficient, and/or nonlinear optic coefficient oriented preferentially in a direction relative to a crystalline or amorphous substrate surface are disclosed. Such films can be used in electronic, electro-optic, and frequency doubling components. 8 figs.

  19. Oriented niobate ferroelectric thin films for electrical and optical devices and method of making such films

    DOEpatents

    Wessels, Bruce W.; Nystrom, Michael J.

    1998-01-01

    Sr.sub.x Ba.sub.1-x Nb.sub.2 O.sub.6, where x is greater than 0.25 and less than 0.75, and KNbO.sub.3 ferroelectric thin films metalorganic chemical vapor deposited on amorphous or crystalline substrate surfaces to provide a crystal axis of the film exhibiting a high dielectric susceptibility, electro-optic coefficient, and/or nonlinear optic coefficient oriented preferentially in a direction relative to a crystalline or amorphous substrate surface. Such films can be used in electronic, electro-optic, and frequency doubling components.

  20. Optical characterization of sputtered carbon films

    SciTech Connect

    Ager, J.W. III

    1992-05-01

    Spattered carbon films are widely used as protective overcoats for thin film disk media. Raman spectroscopy is nondestructive and relatively rapid and is well suited for the characterization of carbon films. Specific features in the Raman spectra are empirically correlated with the rates of specific types of mechanical wear for both hydrogenated and unhydrogenated films. This observation is interpreted in terms of a random covalent network, in which the mechanical performance of the film is determined by the nature of the bonding that links sp{sup 2}-bonded domains.

  1. Integrated optical components in thin films of polymers

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey; Abdeldayem, Hossin; Venkateswarlu, Putcha; Teague, Zedric

    1995-01-01

    The results will be reported on the study of integrated optical components based on nonlinear optical polymeric films. Polymers poly(methyl methacrylate) (PMMA) and polyimide (PI) doped with organic laser dyes 4-dicyanomethylene-2-methyl-6-p dimethylaminostyryl-4H pyran (DCM) and 1, 3, 5, 7, 8 - pentamethyl-2,6 -diethyl-pyrromethene -BF2-complex (Pyrommethene 567, PM-567) were selected as materials for light guiding films. Additionally, UV polymerized polydiacetylene (PDA) on glass substrate was used as a waveguide material. Optical waveguides were fabricated using spin coating of preoxidized silicon wafers (1.5 micrometer silicon oxide layer) with organic dye/polymer solution followed by soft baking. the modes in slab waveguides were studied using prism coupling techniques. Measured values of mode coupling angles in multimode waveguides were used to calculate film thickness and refractive index for different polarizations. Refractive index anisotropy was found in PDA waveguide. The optimal conditions of spin coating for single mode waveguide fabrication were estimated. Propagation losses were measured by collecting the light scattered from the trace of a propagating mode either by scanning photo detector or by CCD camera. Different types of light coupling techniques were used including end-dire coupling, prism and grating coupling. Mechanical printing technique was developed for coupling grating fabrication resulting in gratings with 4% diffraction efficiency. The gratings demonstrated good stability with diffraction efficiency relaxation rate 2.4 dB/hour at a temperature approximately 15-20 C below glass transition point. Dye doped waveguides were transversally pumped with frequency doubled Nd:YAG Q-switched laser producing intensive light emission with apparent 6 kW/sq cm pump threshold and spectrum narrowing near 617 nm peak in the case of DCM doped waveguide. PM-567 doped waveguide pumped with CW Ar(+) laser (514 nm wavelength) far below threshold (0.1 W

  2. Integrated optical components in thin films of polymers

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey; Abdeldayem, Hossin; Venkateswarlu, Putcha; Teague, Zedric

    1995-01-01

    The results will be reported on the study of integrated optical components based on nonlinear optical polymeric films. Polymers poly(methyl methacrylate) (PMMA) and polyimide (PI) doped with organic laser dyes 4-dicyanomethylene-2-methyl-6-p dimethylaminostyryl-4H pyran (DCM) and 1, 3, 5, 7, 8 - pentamethyl-2,6 -diethyl-pyrromethene -BF2-complex (Pyrommethene 567, PM-567) were selected as materials for light guiding films. Additionally, UV polymerized polydiacetylene (PDA) on glass substrate was used as a waveguide material. Optical waveguides were fabricated using spin coating of preoxidized silicon wafers (1.5 micrometer silicon oxide layer) with organic dye/polymer solution followed by soft baking. the modes in slab waveguides were studied using prism coupling techniques. Measured values of mode coupling angles in multimode waveguides were used to calculate film thickness and refractive index for different polarizations. Refractive index anisotropy was found in PDA waveguide. The optimal conditions of spin coating for single mode waveguide fabrication were estimated. Propagation losses were measured by collecting the light scattered from the trace of a propagating mode either by scanning photo detector or by CCD camera. Different types of light coupling techniques were used including end-dire coupling, prism and grating coupling. Mechanical printing technique was developed for coupling grating fabrication resulting in gratings with 4% diffraction efficiency. The gratings demonstrated good stability with diffraction efficiency relaxation rate 2.4 dB/hour at a temperature approximately 15-20 C below glass transition point. Dye doped waveguides were transversally pumped with frequency doubled Nd:YAG Q-switched laser producing intensive light emission with apparent 6 kW/sq cm pump threshold and spectrum narrowing near 617 nm peak in the case of DCM doped waveguide. PM-567 doped waveguide pumped with CW Ar(+) laser (514 nm wavelength) far below threshold (0.1 W

  3. Quantum Electrostatic Model for Optical Properties of Nanoscale Gold Films

    NASA Astrophysics Data System (ADS)

    Qian, Haoliang; Xiao, Yuzhe; Lepage, Dominic; Chen, Li; Liu, Zhaowei

    2015-11-01

    The optical properties of thin gold films with thickness varying from 2.5 nm to 30 nm are investigated. Due to the quantum size effect, the optical constants of the thin gold film deviate from the Drude model for bulk material as film thickness decreases, especially around 2.5 nm, where the electron energy level becomes discrete. A theory based on the self-consistent solution of the Schrödinger equation and the Poisson equation is proposed and its predictions agree well with experimental results.

  4. Stress measurement in thin films by geometrical optics

    NASA Technical Reports Server (NTRS)

    Rossnagel, S. M.; Gilstrap, P.; Rujkorakarn, R.

    1982-01-01

    A variation of Newton's rings experiment is proposed for measuring film stress. The procedure described, the geometrical optics method, is used to measure radii of curvature for a series of film depositions with Ta, Al, and Mo films. The method has a sensitivity of 1 x 10 to the 9th dyn/sq cm, corresponding to the practical radius limit of about 50 m, and a repeatability usually within five percent. For the purposes of comparison, radii are also measured by Newton's rings method and the Talysurf method; all results are found to be in general agreement. Measurement times are also compared: the geometrical optics method requires only 1/2-1 minute. It is concluded that the geometrical optics method provides an inexpensive, fast, and a reasonably correct technique with which to measure stresses in film.

  5. All-optical light modulation in bacteriorhodopsin films

    NASA Astrophysics Data System (ADS)

    Aranda, F. J.; Garimella, R.; McCarthy, N. F.; Narayana Rao, D.; Rao, D. V. G. L. N.; Chen, Z.; Akkara, J. A.; Kaplan, D. L.; Roach, J. F.

    1995-07-01

    We report a convenient method to obtain all-optical light modulation in bacteriorhodopsin films using a degenerate four-wave mixing geometry. Chemically stabilized films of bacteriorhodopsin in a polymer matrix for which the lifetime of the excited M state is tens of seconds were used to demonstrate all-optical light intensity modulation. The films are observed to be stable over a period of 4 years. Due to the sensitivity of the films, small intensities of order microwatt/ cm2 are required in the modulation experiments. Furthermore the fast photochemical transition from M to B permit reasonably fast modulation speeds independent of the slow thermal M and B relaxation time. The experimental system also acts as an all-optical switch where a low power blue pulse turns on a signal red beam.

  6. An optical filter with angular selectivity of the light transmission

    NASA Astrophysics Data System (ADS)

    Zakirullin, Rustam S.

    2015-09-01

    Features of the application of a novel optical filter with angular selectivity of the light transmission to architectural glazing are considered. The filter consists of a sheet transparent substrate with thin-film grating layers on both surfaces. The gratings formed by directionally transmissive strips, alternating with absorptive, reflective, or scattering strips. Their relative position on the input and output surfaces provides angular selectivity of the directional light transmission - as the incidence angle changes, the proportion of radiation that passes through both gratings of the filter also changes. Chromogenic materials currently used in the laminated smart windows, providing control over the intensity and spectrum of the transmitted solar radiation, cannot achieve the selective regulation on the ranges of incidence angles. Such a regulation requires the use of additional daylight-redirecting devices, especially blinds, to dynamically adapt to the position of the sun. The grating optical filter provides angular selectivity of the light transmission of a window without such devices. The features of using this filter in the single and double glazed windows are described. A graphic analytical calculation method is proposed for estimating the effect of geometrical and optical parameters of the filter on the angular characteristics of the light transmission. An algorithm to optimize filtering solar radiation taking into account the geographical coordinates of terrain, time of day and year and the orientation of the window to the cardinal is set. An algorithm to calculating geometrical parameters of the filter with pre-specified characteristics of the light transmission is obtained.

  7. The Deposition of Electro-Optic Films on Semiconductors

    DTIC Science & Technology

    1993-10-08

    Electro - optic properties of KNbO3 films on MgO are found to be similar to bulk, although the scattering losses are very high for these films. In comparison KNbO3 films grown on KTaO3 exhibit low losses of less than 8 dB, while losses for films on spinel showed to be in between those two. The variety of substrates provide us with differences in lattice mismatch, refractive index mismatch, surface morphologies, and microstructure, all of which influence loss

  8. Optical selection and collection of DNA fragments

    DOEpatents

    Roslaniec, Mary C.; Martin, John C.; Jett, James H.; Cram, L. Scott

    1998-01-01

    Optical selection and collection of DNA fragments. The present invention includes the optical selection and collection of large (>.mu.g) quantities of clonable, chromosome-specific DNA from a sample of chromosomes. Chromosome selection is based on selective, irreversible photoinactivation of unwanted chromosomal DNA. Although more general procedures may be envisioned, the invention is demonstrated by processing chromosomes in a conventional flow cytometry apparatus, but where no droplets are generated. All chromosomes in the sample are first stained with at least one fluorescent analytic dye and bonded to a photochemically active species which can render chromosomal DNA unclonable if activated. After passing through analyzing light beam(s), unwanted chromosomes are irradiated using light which is absorbed by the photochemically active species, thereby causing photoinactivation. As desired chromosomes pass this photoinactivation point, the inactivating light source is deflected by an optical modulator; hence, desired chromosomes are not photoinactivated and remain clonable. The selection and photoinactivation processes take place on a microsecond timescale. By eliminating droplet formation, chromosome selection rates 50 times greater than those possible with conventional chromosome sorters may be obtained. Thus, usable quantities of clonable DNA from any source thereof may be collected.

  9. Frequency Selective Volumes for Optical Spatial Filters

    SciTech Connect

    E Topsakal; JL Volakis

    2004-04-15

    A new model is proposed for modeling metallic losses at optical frequencies and is used in the analysis of Frequency Selective Surfaces (FSSs) and Volumes (FSVs). Conventional methods for simulating metallic losses are also outlined and a comparison with those models is given for a patch FSS. Measured data for a slot-ring FSS are also given for model validation.

  10. Magnetic and optical properties of nanocorrugated Co films

    SciTech Connect

    Sapozhnikov, M. V.; Gusev, S. A.; Rogov, V. V.; Ermolaeva, O. L.; Troitskii, B. B.; Khokhlova, L. V.; Smirnov, D. A.

    2010-03-22

    Nanostructured Co films were prepared on the top of a polymethyl methacrylate (PMMA) colloidal crystals by magnetron sputtering. Optical reflectance spectra were studied in the range of near UV, IR, and visible light for p- and s-polarizations. Valleys were observed in the spectra and their positions scaled with the PMMA sphere diameter. Both the surface plasmon resonance and the dipole resonance of single Co nanocaps should be considered to explain the obtained results. Magneto-optic measurements showed the qualitative change of the magnetization curve and the enhancement of magneto-optic rotation at wavelength lambda=632 nm in comparison with the control Co film.

  11. A selective optical sensor based on [9]mercuracarborand-3, a new type of ionophore with a chloride complexing cavity

    NASA Technical Reports Server (NTRS)

    Badr, I. H.; Johnson, R. D.; Diaz, M.; Hawthorne, M. F.; Bachas, L. G.; Daunert, S. (Principal Investigator)

    2000-01-01

    A highly selective optical sensor for chloride, based on the multidentate Lewis acid ionophore [9]mercuracarborand-3, is described herein. This sensor is constructed by embedding the mercuracarborand ionophore, a suitable pH-sensitive lipophilic dye, and lipophilic cationic sites in a plasticized polymeric membrane. The multiple complementary interactions offered by the preorganized complexing cavity of [9]mercuracarborand-3 is shown to control the anion selectivity pattern of the optical film. The film exhibits a significantly enhanced selectivity for chloride over a variety of lipophilic anions such as perchlorate, nitrate, salicylate, and thiocyanate. Furthermore, the optical selectivity coefficients obtained for chloride over other biologically relevant anions are shown to meet the selectivity requirements for the determination of chloride in physiological fluids, unlike previously reported chloride optical sensors. In addition, the optical film responds to chloride reversibly over a wide dynamic range (16 microM-136 mM) with fast response and recovery times.

  12. A selective optical sensor based on [9]mercuracarborand-3, a new type of ionophore with a chloride complexing cavity

    NASA Technical Reports Server (NTRS)

    Badr, I. H.; Johnson, R. D.; Diaz, M.; Hawthorne, M. F.; Bachas, L. G.; Daunert, S. (Principal Investigator)

    2000-01-01

    A highly selective optical sensor for chloride, based on the multidentate Lewis acid ionophore [9]mercuracarborand-3, is described herein. This sensor is constructed by embedding the mercuracarborand ionophore, a suitable pH-sensitive lipophilic dye, and lipophilic cationic sites in a plasticized polymeric membrane. The multiple complementary interactions offered by the preorganized complexing cavity of [9]mercuracarborand-3 is shown to control the anion selectivity pattern of the optical film. The film exhibits a significantly enhanced selectivity for chloride over a variety of lipophilic anions such as perchlorate, nitrate, salicylate, and thiocyanate. Furthermore, the optical selectivity coefficients obtained for chloride over other biologically relevant anions are shown to meet the selectivity requirements for the determination of chloride in physiological fluids, unlike previously reported chloride optical sensors. In addition, the optical film responds to chloride reversibly over a wide dynamic range (16 microM-136 mM) with fast response and recovery times.

  13. Optical response and activity of ultrathin films of topological insulators

    NASA Astrophysics Data System (ADS)

    Parhizgar, Fariborz; Moghaddam, Ali G.; Asgari, Reza

    2015-07-01

    We investigate the optical properties of ultrathin film of a topological insulator in the presence of an in-plane magnetic field. We show that due to the combination of the overlap between the surface states of the two layers and the magnetic field, the optical conductivity can show strong anisotropy. This leads to the effective optical activity of the ultrathin film by influencing the circularly polarized incident light. Intriguingly, for a range of magnetic fields, the reflected and transmitted lights exhibit elliptic character. Even for certain values almost linear polarizations are obtained, indicating that the thin film can act as a polaroid in reflection. All these features are discussed in the context of the time-reversal symmetry breaking as one of the key ingredients for the optical activity.

  14. Gas permeability and selectivity of cellulose nanocrystals films (layers) deposited by spin coating.

    PubMed

    Herrera, Martha A; Mathew, Aji P; Oksman, Kristiina

    2014-11-04

    Cellulose nanocrystals (CNC) were extracted from a cellulose residue using two different acid hydrolysis procedures. CNC extracted with sulfuric acid (CNC(S)) showed higher surface charge (339 μmol/g) compared with crystals extracted with hydrochloric acid (CNC(HCl)). Spin-coated films with two different configurations were prepared; the first with alternate layers of poly(allylamine hydrochloride) (PAHCl) and CNC, and the second with a single layer of PAHCl coated with multilayers of CNC. Film characteristics such as roughness, thickness, contact angle, orientation, gas permeability and gas selectivity were studied. Optical microscopy showed more homogeneous films of CNC(S) compared to CNC(HCl). The surface charge of the crystals impacted the films' hydrophobicity, being highest for 25 alternate layers of PAHCl and CNC(HCl). The gas permeability coefficient was different for each film, depending primarily on the surface charge of the crystals and secondly on the film configuration. The films made with CNC(HCl) displayed gas barriers with nitrogen and oxygen, and gas selectivity with some gas combinations. CNC(S) films did not show gas selectivity. These results indicate that CNC with low surface charge can be further developed for gas separation and barrier applications.

  15. Optical properties of thin films composed of complex hexaborides of rare-earth metals

    SciTech Connect

    Bessareba, V.I.; Dudnik, E.M.; Ivanchenko, L.A.

    1995-07-01

    The range of physical properties characteristic of hexaborides of rare-earth metals (REMs), connected with features of their chemical bonding, make these compounds promising as materials for optics and electronics. In particular, according to the data in, massive specimens of MeB{sub 6} can be used to create mirrors and optical filters. Technologies have been developed to obtain thin films of MeB{sub 6} by electron-beam and cathode sputtering of the corresponding compounds, which are then used to make vacuum condensates of congruently melting hexaborides of the cerium group and incongruently melting hexaborides of the yttrium group. As do massive materials, films exhibit selective reflection (and, accordingly, selective transmission), which is related to the resonance of free charge carriers in their plasmas. Here, the energy position of the resonance depends on the chemical composition of the material and the conditions under, which the condensate is obtained. Thus, by using different methods to obtain thin films and by varying process parameters such as condensation and annealing rates and temperatures, it is possible to change the energy position of the plasma extrema in their optical spectra. The high level of reflection of MeB{sub 6} films in the infrared region, the low level of transmission in the ultraviolet region, and the extreme transmission and reflection in the visible region make it possible to use these coatings as selective optical filters.

  16. Plasmonic transparent conducting metal oxide nanoparticles and nanoparticle films for optical sensing applications

    SciTech Connect

    Ohodnicki, Paul R; Wang, Congjun; Andio, Mark

    2013-07-31

    The ability to monitor gas species selectively, sensitively, and reliably in extreme temperatures and harsh conditions is critically important for more efficient energy production using conventional fossil energy based production technologies, enabling advanced technologies for fossil based power plants of the future, and improving efficiency in domestic manufacturing industries. Optical waveguide based sensing platforms have become increasingly important but a need exists for materials that exhibit useful changes in optical properties in response to changing gas atmospheres at high temperatures. In this manuscript, the onset of a near-IR absorption associated with an increase in free carrier density in doped metal oxide nanoparticles to form so-called conducting metal oxides is discussed in the context of results obtained for undoped and Al-doped ZnO nanoparticle based films. Detailed film characterization results are presented along with measured changes in optical absorption resulting from various high temperature treatments in a range of gas atmospheres. Optical property changes are also discussed in the context of a simple model for optical absorption in conducting metal oxide nanoparticles and thin films. The combination of experimental results and theoretical modeling presented here suggests that such materials have potential for high temperature optical gas sensing applications. Simulated sensing experiments were performed at 500 °C and a useful, rapid, and reproducible near-IR optical sensing response to H{sub 2} confirms that this class of materials shows great promise for optical gas sensing.

  17. Formation of microstructures by selective wet-etching of amorphous As-S-Se thin films

    NASA Astrophysics Data System (ADS)

    Bulanovs, A.; Snikeris, J.

    2014-10-01

    The present article is focused on the optical properties of amorphous As-S-Se thin films and chemical wet-etching in organic non-aqua amine-based solution. Different etching rates depending upon the sample exposure dose and etchant concentration were found. The maximum selective etching ratio 7:1 for samples was achieved. An interference method of in situ real-time monitoring of etching rate for the area with different exposure doses for the same sample was proposed. The efficiency of formation of relief gratings for amorphous As-S-Se thin films depending on the exposure dose was studied. Quality holographic gratings with diffraction efficiency (DE) of up to 65% were received. The results of the current study demonstrate an adequate etching selectivity for fabricating micro structures and possibility of practical application of amorphous chalcogenide thin films in holography and optical lithography.

  18. Optimizing the sensitivity of porous thin film optical sensors

    NASA Astrophysics Data System (ADS)

    Mackay, Tom G.

    2012-10-01

    We considered a porous thin film as a platform for optical sensing. It is envisaged that the porous thin filmbecomes infiltrated by a fluid containing an agent to be sensed. The basis for detection of this agent to besensed is provided by changes in the optical properties of the infiltrated porous thin film. Provided that thepore sizes are much smaller than the wavelengths involved, the infiltrated porous thin film may be regardedas a homogenized composite material. Using the well-established Bruggeman homogenization formalism, thesensitivity of such an optical sensor was investigated theoretically. The sensitivity was considered in relation tothe optical properties of the porous thin film and the infiltrating fluid, the porosity of the thin film, and theshape of the pores. For the case of an isotropic dielectric porous thin film of relative permittivity ɛa and anisotropic dielectric fluid of relative permittivity ɛb, the sensitivity was found to be maximized if: (i) the contrast between ɛa and ɛb was maximized; (ii) mid-range values of porosity were used; (iii) the regime 0 < ɛb < 1 with ɛa » 1 pertained, for example; and (iv) pores which have elongated spheroidal shapes were incorporated.

  19. Optical properties of vanadium dioxide and vanadium pentoxide thin films.

    PubMed

    Chain, E E

    1991-07-01

    Several oxides of vanadium undergo a transition from a semiconductor or insulating state to a metal phase at a critical temperature. Vanadium dioxide undergoes this transition near 68 degrees C, while V(2)O(5) undergoes a similar phase transition near 257 degrees C. During the transition a change in oxide crystal structure is accompanied by large changes in electrical and optical behavior. Thin films of vanadium oxides are capable of reversibly switching from the semiconductor to the metallic state at high speeds and with high spatial resolution. Therefore, these oxides have potential use, particularly in thin film form, for a wide variety of applications involving thermally activated electronic or optical switching devices. Such films are of considerable technical interest because of applications in chemical sensors, energy-conserving coatings, transparent conductors, and switching materials. The numerous potential electronic, optical, and optoelectronic device applications which have been suggested have stimulated work on the preparation of thin films by a variety of techniques, including chemical vapor deposition, solgel, evaporation, and sputter deposition. This paper reviews the optical properties of vanadium oxide coatings and stresses the dependence of film properties on sample preparation and resultant film microstructure.

  20. Thin film/liquid crystal composite optical materials

    NASA Astrophysics Data System (ADS)

    Sit, Jeremy C.; Brett, Michael J.

    2004-01-01

    The classic challenge faced by researchers dealing with liquid crystals is to control the LC molecular orientation and hence optimise the optical properties. Well known techniques for influencing LC texture include the use of surfactants or thin film alignment layers. The underlying limitation common to such techniques is that while excellent control of LC anchoring at the substrate surface is achieved, molecular alignment in the bulk of the LC is reliant entirely upon the cooperative effects and resulting elastic properties of the LC material. Generally, this has worked sufficiently well in practice, but unfortunately, the complete dependence on the intermolecular forces of the LC means that unencumbered, reversible switching is not always possible. Our group has taken a unique approach to influence LC orientation. Using glancing angle deposition (GLAD), highly porous thin films can be grown possessing isolated columnar microstructure whose shape can be tailored via substrate motion during film deposition. In particular, we can grow films of helical columns with controlled pitch and handedness. These films exhibit circular dichroism and optical activity similar to that seen in chiral LCs. The high porosity of GLAD films permits fluids such as LCs to be introduced into the pores, leading to a new type of hybrid optical material. Most significantly, initial work showed that when achiral LCs were embedded in chiral GLAD media, there was an enhancement of the circular dichroism and optical activity as the chiral GLAD film served to induce a chiral orientation in the LC. In this report, we start with a brief overview of the GLAD process and some relevant optical studies, leading to a review of GLAD/LC hybrid materials, switchable devices, and finally, a discussion of recent research optical characterisation and some ideas for future avenues of investigation.

  1. Thin film/liquid crystal composite optical materials

    NASA Astrophysics Data System (ADS)

    Sit, Jeremy C.; Brett, Michael J.

    2003-12-01

    The classic challenge faced by researchers dealing with liquid crystals is to control the LC molecular orientation and hence optimise the optical properties. Well known techniques for influencing LC texture include the use of surfactants or thin film alignment layers. The underlying limitation common to such techniques is that while excellent control of LC anchoring at the substrate surface is achieved, molecular alignment in the bulk of the LC is reliant entirely upon the cooperative effects and resulting elastic properties of the LC material. Generally, this has worked sufficiently well in practice, but unfortunately, the complete dependence on the intermolecular forces of the LC means that unencumbered, reversible switching is not always possible. Our group has taken a unique approach to influence LC orientation. Using glancing angle deposition (GLAD), highly porous thin films can be grown possessing isolated columnar microstructure whose shape can be tailored via substrate motion during film deposition. In particular, we can grow films of helical columns with controlled pitch and handedness. These films exhibit circular dichroism and optical activity similar to that seen in chiral LCs. The high porosity of GLAD films permits fluids such as LCs to be introduced into the pores, leading to a new type of hybrid optical material. Most significantly, initial work showed that when achiral LCs were embedded in chiral GLAD media, there was an enhancement of the circular dichroism and optical activity as the chiral GLAD film served to induce a chiral orientation in the LC. In this report, we start with a brief overview of the GLAD process and some relevant optical studies, leading to a review of GLAD/LC hybrid materials, switchable devices, and finally, a discussion of recent research optical characterisation and some ideas for future avenues of investigation.

  2. Guide to Selected Student Film Awards.

    ERIC Educational Resources Information Center

    Barley, Steven D.

    Students who are beginning to use film as a medium of expression are sometimes more highly motivated to achieve excellence if they know channels through which they can seek acclaim for their films. Listed here are three highly accessible competitive events through which acclaim may be sought. Each event is described briefly, offering information…

  3. Guide to Selected Student Film Awards.

    ERIC Educational Resources Information Center

    Barley, Steven D.

    Students who are beginning to use film as a medium of expression are sometimes more highly motivated to achieve excellence if they know channels through which they can seek acclaim for their films. Listed here are three highly accessible competitive events through which acclaim may be sought. Each event is described briefly, offering information…

  4. Growth, polishing, and optical scatter of diamond thin films

    NASA Astrophysics Data System (ADS)

    Thorpe, Thomas P.; Morrish, Arthur A.; Hanssen, Leonard M.; Butler, James E.; Snail, Keith A.

    1990-12-01

    Polycrystalline diamond films have been synthesized in an oxygen-acetylene flame (15-20 tm thick and in a filament-assisted CYD reactor (10-60 p. m thick). The quality of the diamond was measured with a Raman microprobe optical and electron microscopes an FTIR and a UV-Vis-NIR spectrophotometer. The hemispherical transmittance and reflectance of several films was measured in the UV visible and infrared with integrating spheres. The transmittance and reflectance was found to depend on which surface of the film faces the spectrophotometer''s beam this result can be explained by total internal reflection effects and the different roughness scales of the film''s two surfaces. Preliminary results on the polishing of several FACVD films using a heated steel disk a rhenium filament and a hydrogen environment are discussed. An Auger depth profile of the steel disk shows graphite at the surface of the disk iron carbide in the bulk and a depletion of carbon in the bulk near the surface. The films'' surface roughness before and after polishing was measured with a profiometer and local roughness averages of A have been achieved. Results of optical scatter measurements made on films before and after polishing are presented. 1.

  5. Extraordinary optical transmission in nanopatterned ultrathin metal films without holes

    NASA Astrophysics Data System (ADS)

    Peer, Akshit; Biswas, Rana

    2016-02-01

    We experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate exhibits extraordinary optical transmission, even though no holes were etched in the film. Our film synthesis started by nanoimprinting a periodic array of nanocups with a period of ~750 nm on a polystyrene film over a glass substrate. A thin non-conformal gold film was sputter-deposited on the polystyrene by angle-directed deposition. The gold film was continuous with spatial thickness variation, the film being thinnest at the bottom of the nanocup. Measurements revealed an extraordinary transmission peak at a wavelength just smaller than the period, with an enhancement of ~2.5 compared to the classically expected value. Scattering matrix simulations model well the transmission and reflectance measurements when an ultrathin gold layer (~5 nm), smaller than the skin depth is retained at the bottom of the nanocups. Electric field intensities are enhanced by >100 within the nanocup, and ~40 in the ultrathin gold layer causing transmission through it. We show a wavelength red-shift of ~30 nm in the extraordinary transmission peak when the nanocups are coated with a thin film of a few nanometers, which can be utilized for biosensing. The continuous corrugated metal films are far simpler structures to observe extraordinary transmission, circumventing the difficult process of etching the metal film. Such continuous metal films with ultrathin regions are simple platforms for non-linear optics, plasmonics, and biological and chemical sensing.We experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate exhibits extraordinary optical transmission, even though no holes were etched in the film. Our film synthesis started by nanoimprinting a periodic array of nanocups with a period of ~750 nm on a polystyrene film over a glass substrate. A thin non-conformal gold film was sputter-deposited on the polystyrene by

  6. Investigation of optical properties of epitaxial yttrium iron garnet films

    SciTech Connect

    Paranin, V. D.

    2016-04-13

    In work we investigated yttrium iron garnet epitaxial films with a thickness of 10 µm and 55 µm which were grown on the surface of garnet substrate. Using the polarizing microscopy method the branching domain structure of films was shown with the period of domains 21.5 µm and 42.5 µm. Disappearance of domains at presence of an external magnetic field up to 100 Oe was noted. The optical transmission of films for the polarized beam of HeNe laser is investigated and zero diffraction order and odd diffraction rings orders were shown. Interconnection of the period of chaotically oriented domains with angles of axially symmetric diffraction rings orders was shown. Diffraction patterns at various longitudinal magnetic fields are investigated. Disappearance of odd diffraction orders and increasing in intensity of zero diffraction order were fixed. Optical transmission of epitaxial films was measured in range of 500 - 900 nm.

  7. Silicon colors: spectral selective perfect light absorption in single layer silicon films on aluminum surface and its thermal tunability.

    PubMed

    Mirshafieyan, Seyed Sadreddin; Guo, Junpeng

    2014-12-15

    Using two most abundant materials in nature: silicon and aluminum, spectral selective perfect light absorption in single layer silicon films on aluminum surface is demonstrated. Perfect light absorption is achieved due to the critical coupling of incident optical wave to the second order resonance mode of the optical cavity made of a thin silicon film on aluminum surface. Spectral selective perfect light absorption results in different optical colors corresponding to different thicknesses of silicon films. The device colors do not change when viewing from large angles with respect to the surface normal. Perfect absorption wavelength can be tuned over a wide wavelength range over 70 nm by thermal annealing. This new technology, which is low cost and compatible with silicon technology platform, paves the way for many applications such as optical color filters and wavelength selective photodetectors.

  8. Multi-beam pulsed laser deposition for advanced thin-film optical waveguides

    NASA Astrophysics Data System (ADS)

    Eason, R. W.; May-Smith, T. C.; Sloyan, K. A.; Gazia, R.; Darby, M. S. B.; Sposito, A.; Parsonage, T. L.

    2014-01-01

    We discuss our progress in the use of multiple laser beams and multiple targets for the pulsed laser deposition of thin films for waveguide laser and magneto-optic applications. In contrast to the more widely used single-beam/single-target geometries, having more than one laser-produced plume can allow tuning of the material properties and complex engineering of the deposited thin films. For optical applications—the majority of the work reported here—dopants can be selectively introduced, lattice mismatch and residual strain can be compensated, which is an important factor for successful growth of thin films of ∼ tens of microns thickness, and refractive index values can be adjusted for fabrication of sophisticated waveguiding structures. We discuss mixed, layered, superlattice and Bragg reflector growth, which involve out-of-plane engineering of the film structure, and in-plane engineered geometries for designs relevant to thin-film disc lasing devices. Finally we briefly discuss our most recent use of multi-plume growth for magneto-optic thin films, which involves compositional tuning of final magnetic properties.

  9. Symmetry driven control of optical properties in WO3 films

    DOE PAGES

    Herklotz, A.; Rus, S. F.; KC, S.; ...

    2017-06-23

    Optical band gap control of semiconducting thin films is critical for the optimization of photoelectronic and photochemical applications. In this work, we demonstrate that the optical band gap of WO3 films can be continuously controlled through uniaxial strain induced by low-energy helium implantation. We show that the implantation of He into epitaxially grown and coherently strained WO3 films can be used to induce single axis out-of-plane lattice expansion of up to 2%. Ellipsometric spectroscopy reveals that this lattice expansion shifts the absorption spectrum to lower energies and effectively reduces the optical band gap by about 0.18 eV per percent expansionmore » of the out-of-plane unit cell length. Furthermore, density functional calculations show that this response is a direct result of changes in orbital degeneracy driven by changes in the octahedral rotations and tilts.« less

  10. Optical thin-film technology: past, present, future

    NASA Astrophysics Data System (ADS)

    Strickland, William P.

    1990-12-01

    The evolution of the vacuum coating industry is reviewed. Vacuum science progressed slowly until the late nineteenth century due to an incomplete understanding of vacuum and lack of applications. Edison's invention of the light bulb launched the vacuum industry and increased developmentof improved vacuum systems. The thin film optical coating industry arose from the needs of the German and U.S. military efforts during World War II. The author presents his experience in thin film coating from 1939 to the present.

  11. Nanocavity enhancement for ultra-thin film optical absorber.

    PubMed

    Song, Haomin; Guo, Luqing; Liu, Zhejun; Liu, Kai; Zeng, Xie; Ji, Dengxin; Zhang, Nan; Hu, Haifeng; Jiang, Suhua; Gan, Qiaoqiang

    2014-05-01

    A fundamental strategy is developed to enhance the light-matter interaction of ultra-thin films based on a strong interference effect in planar nanocavities, and overcome the limitation between the optical absorption and film thickness of energy harvesting/conversion materials. This principle is quite general and is applied to explore the spectrally tunable absorption enhancement of various ultra-thin absorptive materials including 2D atomic monolayers.

  12. Multi-wavelength optical storage of diarylethene PMMA film

    NASA Astrophysics Data System (ADS)

    Guo, Haobo; Zhang, Fushi; Wu, Guo-shi; Sun, Fan; Pu, Shouzhi; Mai, Xuesong; Qi, Guosheng

    2003-05-01

    Current commercial optical storage technologies are all based on the heat effect of the recording laser, i.e., heat-mode optical storage. In the present work, photon-mode optical storage using photochromic diarylethene materials was investigated. Two diarylethene derivatives were dispersed into PMMA solution, and spin-coated on a glass substrate with Al reflective layer as the recording layer. Two laser beams of 532 and 650 nm were used in recording and readout simultaneously, and signals with high S/ N ratio were detected. Multi-wavelength optical storage was realized with the diarylethene PMMA film.

  13. Steerable optical antennas by selective heating.

    PubMed

    Cuadrado, Alexander; González, Francisco Javier; Alda, Javier

    2014-04-01

    Directional steerability can be obtained for an array of optical antennas through selective heating of the individual elements. Heating changes electrical conductivity of the heated element, which affects the phase of the generated currents. The variation in temperature can be obtained by modifying the biasing point of the individual elements of the array, which would allow fast reconfiguration. The numerical evaluation of the performance of an array of a reduced number of antennas (2 and 3) shows the feasibility of this approach.

  14. A Selection of Films for Family Planning Programmes.

    ERIC Educational Resources Information Center

    International Planned Parenthood Federation, London (England).

    This catalog gives an annotated listing of selected films available for use in family planning programs. Films are listed alphabetically, geographically by particular country, and by subject. In most cases information is given concerning length, producer, distributor, cost, and rental conditions from the International Planned Parenthood…

  15. Fiber-Optic Sensor Would Monitor Growth of Polymer Film

    NASA Technical Reports Server (NTRS)

    Beamesderfer, Michael

    2005-01-01

    A proposed optoelectronic sensor system would measure the increase in thickness of a film of parylene (a thermoplastic polymer made from para-xylene) during growth of the film in a vapor deposition process. By enabling real-time monitoring of film thickness, the system would make it possible to identify process conditions favorable for growth and to tailor the final thickness of the film with greater precision than is now possible. The heart of the sensor would be a pair of fiber-optic Fabry-Perot interferometers, depicted schematically in the figure. (In principle, a single such interferometer would suffice. The proposal calls for the use of two interferometers for protective redundancy and increased accuracy.) Each interferometer would include a light source, a fiber-optic coupler, and photodetectors in a control box outside the deposition chamber. A single-mode optical fiber for each interferometer would run from inside the control box to a fused-silica faceplate in a sensor head. The sensory tips of the optical fibers would be polished flush with the free surface of the faceplate. In preparation for use, the sensor head would be mounted with a hermetic seal in a feed-through port in the deposition chamber, such that free face of the faceplate and the sensory tips of the optical fibers would be exposed to the deposition environment. During operation, light would travel along each optical fiber from the control box to the sensor head. A small portion of the light would be reflected toward the control box from the end face of each fiber. Once growth of the parylene film started, a small portion of the light would also be reflected toward the control box from the outer surface of the film. In the control box, the two reflected portions of the light beam would interfere in one of the photodetectors. The difference between the phases of the interfering reflected portions of the light beam would vary in proportion to the increasing thickness of the film and the known

  16. Optical constant of thin gold films: Structural morphology determined optical response

    NASA Astrophysics Data System (ADS)

    Yakubovsky, D. I.; Fedyanin, D. Yu.; Arsenin, A. V.; Volkov, V. S.

    2017-09-01

    The performance of metal-based devices is limited by ohmic losses in the metal, which are determined by electron scattering. The structural properties of gold thin films also play an important role in the film quality, which may affect its' optical properties and the overall capability of the device. At the same time, metal films of different thicknesses are needed for different applications and, since these films are polycrystalline, their internal properties and surface roughness can greatly vary from one thickness to another. In this work, we study, using atomic force microscopy and spectroscopic ellipsometry, the structural morphology and optical properties of polycrystalline gold thin films (fabricated by e-beam deposition at a low sputtering rate smooth gold) in the thickness range of 20 - 200 nm. By extracting the real and imaginary dielectric function and the Drude parameter of electron relaxation rate we demonstrate that the optical losses increase mainly when the film thickness gets lower than 66 nm. Our results reveal that the thickness-dependent contribution is inversely proportional to the film thickness. The experimental results are confirmed by the theoretical model, which predicts optical losses based on structure of the gold films.

  17. Optical selection rules of zigzag graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Saroka, V. A.; Shuba, M. V.; Portnoi, M. E.

    2017-04-01

    We present an analytical tight-binding theory of the optical properties of graphene nanoribbons with zigzag edges. Applying the transfer matrix technique to the nearest-neighbor tight-binding Hamiltonian, we derive analytical expressions for electron wave functions and optical transition matrix elements for incident light polarized along the structure axis. It follows from the obtained results that optical selection rules result from the wave function parity factor (-1) J, where J is the band number. These selection rules are that Δ J is odd for transitions between valence and conduction subbands and that Δ J is even for transitions between only valence (conduction) subbands. Although these selection rules are different from those in armchair carbon nanotubes, there is a hidden correlation between absorption spectra of the two structures that should allow one to use them interchangeably in some applications. The correlation originates from the fact that van Hove singularities in the tubes are centered between those in the ribbons if the ribbon width is about a half of the tubes circumference. The analysis of the matrix elements dependence on the electron wave vector for narrow ribbons shows a smooth nonsingular behavior at the Dirac points and the points where the bulk states meet the edge states.

  18. Structural and optical characterization of the propolis films

    NASA Astrophysics Data System (ADS)

    Drapak, S. I.; Bakhtinov, A. P.; Gavrylyuk, S. V.; Drapak, I. T.; Kovalyuk, Z. D.

    2006-10-01

    We have performed structural and optical characterizations of the propolis (an organic entity of biological nature) films grown on various non-organic substrates. The films were grown from a propolis melt or a propolis alcohol solution. The crystal structure has been observed in the films precipitated from the solution onto substrates such as an amorphous glass and sapphire or semiconductor indium monoselenide. For any growth method, the propolis film is a semiconductor with the bandgap of 3.07 eV at 300 K that is confirmed by a maximum in photoluminescence spectra at 2.86 eV. We argue that propolis films might be used in various optoelectronic device applications.

  19. Evaluation of optically transparent polyetherimide films for applications in space

    NASA Technical Reports Server (NTRS)

    St. Clair, Anne K.; Slemp, Wayne S.

    1991-01-01

    Several series of aromatic polyetherimide films have been synthesized and characterized with the objective of obtaining maximum optical transparency for applications in space. Incorporation of phenoxy groups into aromatic polyimides has resulted in a reduction in the color intensity of these films compared to commercial polyimide film by reducing electronic interactions between polymer chains. The resulting lightly colored to colorless polyetherimide films have been characterized by UV-visible and infrared spectroscopy before and after exposure to varying doses of UV and electron irradiation designed to simulate use as second-surface mirror thermal control coatings. After exposure to 300 equivalent solar hours UV irradiation and 1 MeV electron irradiation, the polyetherimides were 2.2 to 2.6 times more transparent than commercial polyimide film of the same thickness.

  20. Symmetry driven control of optical properties in WO3 films

    NASA Astrophysics Data System (ADS)

    Herklotz, A.; Rus, S. F.; KC, S.; Cooper, V. R.; Huon, A.; Guo, E.-J.; Ward, T. Z.

    2017-06-01

    In this work, we demonstrate that the optical bandgap of WO3 films can be continuously controlled through uniaxial strain induced by low-energy helium implantation. The insertion of He into epitaxially grown and coherently strained WO3 films can be used to induce single axis out-of-plane lattice expansion of up to 2%. Ellipsometric spectroscopy reveals that the optical bandgap is reduced by about 0.18 eV per percent expansion of the out-of-plane unit cell length. Density functional theory calculations show that this response is a direct result of changes in orbital degeneracy driven by changes in the octahedral rotations and tilts.

  1. Optical Properties of Silver Particulate Films on Modified Polymer Substrates

    NASA Astrophysics Data System (ADS)

    Gurumurthy, S. C.; Pattabi, Manjunatha; Sanjeeva, Ganesh

    2011-07-01

    Results of the investigations carried out on the optical properties of particulate films deposited on 8 MeV electron beam irradiated polystyrene (PS) and on blends of PS and Poly (4-vinyl pyridine) (P4VP) are reported. It is observed that absorption maxima shift towards higher wavelength for films deposited on irradiated polystyrene and on blends of PS and P4VP. These results indicate that morphology of the particulate films can be changed by tuning the metal polymer interaction in an inert polymer through electron beam irradiation or by blending it with an interacting polymer like P4VP.

  2. Method to adjust multilayer film stress induced deformation of optics

    DOEpatents

    Spiller, Eberhard A.; Mirkarimi, Paul B.; Montcalm, Claude; Bajt, Sasa; Folta, James A.

    2000-01-01

    Stress compensating systems that reduces/compensates stress in a multilayer without loss in reflectivity, while reducing total film thickness compared to the earlier buffer-layer approach. The stress free multilayer systems contain multilayer systems with two different material combinations of opposite stress, where both systems give good reflectivity at the design wavelengths. The main advantage of the multilayer system design is that stress reduction does not require the deposition of any additional layers, as in the buffer layer approach. If the optical performance of the two systems at the design wavelength differ, the system with the poorer performance is deposited first, and then the system with better performance last, thus forming the top of the multilayer system. The components for the stress reducing layer are chosen among materials that have opposite stress to that of the preferred multilayer reflecting stack and simultaneously have optical constants that allow one to get good reflectivity at the design wavelength. For a wavelength of 13.4 nm, the wavelength presently used for extreme ultraviolet (EUV) lithography, Si and Be have practically the same optical constants, but the Mo/Si multilayer has opposite stress than the Mo/Be multilayer. Multilayer systems of these materials have practically identical reflectivity curves. For example, stress free multilayers can be formed on a substrate using Mo/Be multilayers in the bottom of the stack and Mo/Si multilayers at the top of the stack, with the switch-over point selected to obtain zero stress. In this multilayer system, the switch-over point is at about the half point of the total thickness of the stack, and for the Mo/Be--Mo/Si system, there may be 25 deposition periods Mo/Be to 20 deposition periods Mo/Si.

  3. Optical characterization of LDEF contaminant film

    NASA Technical Reports Server (NTRS)

    Blakkolb, Brian K.; Ryan, Lorraine E.; Bowen, Howard S.; Kosic, Thomas J.

    1993-01-01

    Dark brown molecular film deposits were found at numerous locations on the Long Duration Exposure Facility (LDEF) and have been documented in great detail by several investigators. The exact deposition mechanism for these deposits is as yet unknown, although direct and scattered atomic oxygen, and solar radiation interacting with materials outgassing products have all been implicated in the formation process. Specimens of the brown molecular film were taken from below the flange of the experimental tray located at position D10 on the LDEF. The tray was one of two, comprising the same experiment, the other being located on the wake facing side of the LDEF satellite at position B4. Having access to both trays, we were able to directly compare the effect that orientation with respect to the atomic oxygen flux vector had on the formation of the brown molecular film deposits. The film is thickest on surfaces facing toward the exterior, i.e. the tray corner, as can be seen by comparing the lee and wake aspects of the rivets. The patterns appear to be aligned not with the velocity vector but with the corner of the tray suggesting that flux to the surface is due to scattered atomic oxygen rather than direct ram impingement. The role of scattered flux is further supported by more faint plume patterns on the sides of the tray. The angle of these plumes is strongly aligned with the ram direction but the outline of the deposit implies that incident atoms are scattered by collisions with the edges of the opening resulting in a directed, but diffuse, flux of atomic oxygen to the surface. Spectral reflectance measurements in the 2 to 10 micron (4000 to 1000 wavenumbers) spectral range are presented for the film in the 'as deposited' condition and for the free standing film. The material was analyzed by FTIR (Fourier Transform Infrared) microspectroscopy using gold as the reference standard. The 'as deposited' specimen was on an aluminum rivet taken from beneath the tray flange

  4. Power selective optical filter devices and optical systems using same

    DOEpatents

    Koplow, Jeffrey P

    2014-10-07

    In an embodiment, a power selective optical filter device includes an input polarizer for selectively transmitting an input signal. The device includes a wave-plate structure positioned to receive the input signal, which includes at least one substantially zero-order, zero-wave plate. The zero-order, zero-wave plate is configured to alter a polarization state of the input signal passing in a manner that depends on the power of the input signal. The zero-order, zero-wave plate includes an entry and exit wave plate each having a fast axis, with the fast axes oriented substantially perpendicular to each other. Each entry wave plate is oriented relative to a transmission axis of the input polarizer at a respective angle. An output polarizer is positioned to receive a signal output from the wave-plate structure and selectively transmits the signal based on the polarization state.

  5. Optical method for the determination of grain orientation in films

    DOEpatents

    Maris, Humphrey J.

    2003-05-13

    A method for the determination of grain orientation in a film sample is provided comprising the steps of measuring a first transient optical response of the film and determining the contribution to the transient optical response arising from a change in the energy distribution of the electrons in the sample, determining the contribution to the transient optical response arising from a propagating strain pulse within the sample, and determining the contribution to the transient optical response arising from a change in sample temperature of the sample. The grain orientation of the sample may be determined using the contributions to the transient optical response arising from the change in the energy distribution of the electrons, the propagating strain pulse, and the change in sample temperature. Additionally, a method for determination of the thickness of a film sample is provided. The grain orientation of the sample is first determined. The grain orientation, together with the velocity of sound and a propagation time of a strain pulse through the sample are then used to determine the thickness of the film sample.

  6. Optical method for the determination of grain orientation in films

    DOEpatents

    Maris, Humphrey J.

    2001-01-01

    A method for the determination of grain orientation in a film sample is provided comprising the steps of measuring a first transient optical response of the film and determining the contribution to the transient optical response arising from a change in the energy distribution of the electrons in the sample, determining the contribution to the transient optical response arising from a propagating strain pulse within the sample, and determining the contribution to the transient optical response arising from a change in sample temperature of the sample. The grain orientation of the sample may be determined using the contributions to the transient optical response arising from the change in the energy distribution of the electrons, the propagating strain pulse, and the change in sample temperature. Additionally, a method for determination of the thickness of a film sample is provided. The grain orientation of the sample is first determined. The grain orientation, together with the velocity of sound and a propagation time of a strain pulse through the sample are then used to determine the thickness of the film sample.

  7. Optical Properties of Magnetron sputtered Nickel Thin Films

    NASA Astrophysics Data System (ADS)

    Twagirayezu, Fidele; Geerts, Wilhelmus J.; Cui, Yubo

    2015-03-01

    The study of optical properties of Nickel (Ni) is important, given the pivotal role it plays in the semiconductor and nano-electronics technology. Ni films were made by DC and RF magnetron sputtering in an ATC Orion sputtering system of AJA on various substrates. The optical properties were studied ex situ by variable angle spectroscopic (220-1000 nm) ellipsometry at room temperature. The data were modeled and analyzed using the Woollam CompleteEase Software fitting ellipsometric and transmission data. Films sputtered at low pressure have optical properties similar to that of Palik. Films sputtered at higher pressure however have a lower refraction index and extinction coefficient. It is expected from our results that the density of the sputtered films can be determined from the ellipsometric quantities. Our experiments also revealed that Ni is susceptible to a slow oxidation changing its optical properties over the course of several weeks. The optical properties of the native oxide differ from those of reactive sputtered NiO similar as found by. Furthermore the oxidation process of our samples is characterized by at least two different time constants.

  8. Bacteriorhodopsin films for optical signal processing and data storage

    NASA Technical Reports Server (NTRS)

    Walkup, John F. (Principal Investigator); Mehrl, David J. (Principal Investigator)

    1996-01-01

    This report summarizes the research results obtained on NASA Ames Grant NAG 2-878 entitled 'Investigations of Bacteriorhodopsin Films for Optical Signal Processing and Data Storage.' Specifically we performed research, at Texas Tech University, on applications of Bacteriorhodopisin film to both (1) dynamic spatial filtering and (2) holographic data storage. In addition, measurements of the noise properties of an acousto-optical matrix-vestor multiplier built for NASA Ames by Photonic Systems Inc. were performed at NASA Ames' Photonics Laboratory. This research resulted in two papers presented at major optical data processing conferences and a journal paper which is to appear in APPLIED OPTICS. A new proposal for additional BR research has recently been submitted to NASA Ames Research Center.

  9. Optical and electrical characterization of bacteriorhodopsin films.

    PubMed

    Dyukova, T; Robertson, B; Weetall, H

    1997-01-01

    The lifetime of the M-state of bacteriorhodopsin (BR) is increased by genetic and chemical modifications and by solubilizing purple membranes (PMs) with detergent. Chemically modified D96E films as well as D96N films, possess close to 100% bleaching efficiency which makes them attractive for use as image storage media. The mutant S35C has spectral and kinetic properties identical to the WT, both in aqueous suspensions and in films. This indicates that substitution of Ser-35 with Cys has an insignificant effect on the photocycling activity of BR. This substitution provides an attachment site that does not interfere with the function of BR. The magnitude of photocurrent transients generated by mutant BR proteins is used to measure the efficiency of the ground-to-M-state transitions.

  10. Optical dispersion relations for diamondlike carbon films

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.; Sieg, Robert M.; Shoemaker, Neil S.; Pouch, John J.

    1989-01-01

    Ellipsometric measurements on plasma deposited diamondlike amorphous carbon (a-C:H) films were taken in the visible, (E=1.75 to 3.5 eV). The films were deposited on Si and their properties were varied using high temperature (up to 750 C) anneals. The real (n) and imaginary (k) parts of the complex index of refraction N were obtained simultaneously. Following the theory of Forouhi and Bloomer, a least squares fit was used to find the dispersion relations n(E) and k(E). Reasonably good fits were obtained, showing that the theory can be used for a-C:H films. Moreover, the value of the energy gap (Eg) obtained in this way was compared to the Eg value using conventional Tauc plots and reasonably good agreement was obtained.

  11. Optical dispersion relations for diamondlike carbon films

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.; Sieg, Robert M.; Shoemaker, Neil S.; Pouch, John J.

    1990-01-01

    Ellipsometric measurements on plasma deposited diamondlike amorphous carbon (a-C:H) films were taken in the visible, (E = 1.75 to 3.5 eV). The films were deposited on Si and their properties were varied using high temperature (up to 750 C) anneals. The real (n) and imaginary (k) parts of the complex index of refraction, N, were obtained simultaneously. Following the theory of Forouhi and Bloomer, a least squares fit was used to find the dispersion relations n(E) and k(E). Reasonably good fits were obtained, showing that the theory can be used for a-C:H films. Moreover, the value of the energy gap, Eg, obtained in this way was compared the the Eg value using conventional Tauc plots and reasonably good agreement was obtained.

  12. Optical dispersion relations for 'diamondlike' carbon films

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.; Sieg, Robert M.; Shoemaker, Neil S.; Pouch, John J.

    1989-01-01

    Ellipsometric measurements on plasma deposited diamondlike amorphous carbon (a-C:H) films were taken in the visible, (E = 1.75 to 3.5 eV). The films were deposited on Si and their properties were varied using high temperature (up to 750 C) anneals. The real (n) and imaginary (k) parts of the complex index of refraction N were obtained simultaneously. Following the theory of Forouhi and Bloomer, a least squares fit was used to find the dispersion relations n(E) and k(E). Reasonably good fits were obtained, showing that the theory can be used for a-C:H films. Moreover, the value of the energy gap (Eg) obtained in this way was compared to the Eg value using conventional Tauc plots and reasonably good agreement was obtained.

  13. Evaluation of Selected Solid Lubricating Films

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2001-01-01

    An investigation was conducted to examine the friction and wear properties of bonded molybdenum disulfide (MoS2), magnetron-sputtered MoS2, ion-plated silver, ion-plated lead, magnetron-sputtered diamondlike carbon (MS DLC), and plasma-assisted, chemical-vapor-deposited DLC (PACVD DLC) films in sliding contact with 6-mm-diameter AISI 440C stainless steel balls. Unidirectional ball-on-disk sliding friction experiments were conducted with a load of 5.9 N and a sliding velocity of 0.2 m/s at room temperature in three environments: ultrahigh vacuum (vacuum pressure, 7 x 10(exp -7) Pa), humid air (relative humidity, approx. 20 percent), and dry nitrogen (relative humidity, less than 1 percent). The main criteria for judging the performance of the solid lubricating films were coefficient of friction and wear rate, which had to be less than 0.3 and on the order of 10(exp -6) cubic mm/N(dot)m or less, respectively. The bonded MoS2 and magnetron-sputtered MoS2 films met the criteria in all three environments. The ion-plated lead and silver films met the criteria only in ultrahigh vacuum but failed in humid air and in dry nitrogen. The MS DLC and PACVD DLC films met the requirements in humid air and dry nitrogen but failed in ultrahigh vacuum.

  14. Durability Evaluation of Selected Solid Lubricating Films

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2001-01-01

    An investigation was conducted to examine the coefficients of friction, wear rates, and durability of bonded molybdenum disulfide (MoS2), magnetron-sputtered MoS2, ion-plated silver, ion-plated lead, magnetron-sputtered diamondlike carbon (MS DLC), and plasma-assisted, chemical-vapor-deposited DLC (PACVD DLC) films in sliding contact with 6-mm-diameter AISI 440C stainless steel balls. Unidirectional ball-on-disk sliding friction experiments were conducted with a load of 5.9 N and a sliding velocity of 0.2 m/s at room temperature in three environments: ultrahigh vacuum (vacuum pressure, 7 x 10(exp -7) Pa), humid air (relative humidity, approx. 20 percent), and dry nitrogen (relative humidity, less than 1 percent). The main criteria for judging the performance of the solid lubricating films were coefficient of friction and wear rate, which had to be less than 0.3 and on the order of 10(exp -6) cu mm/N.m or less, respectively. The bonded MoS2 and magnetron-sputtered MoS2 films met the criteria in all three environments. The ion-plated lead and silver films met the criteria only in ultrahigh vacuum but failed in humid air and in dry nitrogen. The MS DLC and PACVD DLC films met the requirements in humid air and dry nitrogen but failed in ultrahigh vacuum.

  15. Optical and morphological properties of sol gel derived titanium dioxide films

    NASA Astrophysics Data System (ADS)

    Sharma, A. B.; Sharma, S. K.; M, Vishwas; Rao, K. Narasimha

    2015-08-01

    Titanium oxide (Titania) thin films were synthesized on different substrates via the sol-gel dip-coating method using alkoxide solution. Some selected samples were also prepared with different percentage of Lead (Pb). The influence of Pb addition in precursor sol on the optical properties of titanium dioxide thin films was studied. The optical transmittance in the visible region has increased with increase in weight percentage of lead. The refractive index was slightly decreased with Pb addition. Crystallization of these coatings was achieved through thermal annealing at temperatures above 400 °C. The structural properties and surface morphology of the crystallized coatings were studied by Scanning Electron Microscopy. Increase in average grain size from 250 nm to 350 nm with increase in Pb concentration is observed. Films were appeared to more coarse with increase in Pb addition. An increase in Pb addition resulted increase in average roughness from 12 nm to 25 nm.

  16. Optical and morphological properties of sol gel derived titanium dioxide films

    SciTech Connect

    Sharma, A. B.; Sharma, S. K.; M, Vishwas; Rao, K. Narasimha

    2015-08-28

    Titanium oxide (Titania) thin films were synthesized on different substrates via the sol-gel dip-coating method using alkoxide solution. Some selected samples were also prepared with different percentage of Lead (Pb). The influence of Pb addition in precursor sol on the optical properties of titanium dioxide thin films was studied. The optical transmittance in the visible region has increased with increase in weight percentage of lead. The refractive index was slightly decreased with Pb addition. Crystallization of these coatings was achieved through thermal annealing at temperatures above 400 °C. The structural properties and surface morphology of the crystallized coatings were studied by Scanning Electron Microscopy. Increase in average grain size from 250 nm to 350 nm with increase in Pb concentration is observed. Films were appeared to more coarse with increase in Pb addition. An increase in Pb addition resulted increase in average roughness from 12 nm to 25 nm.

  17. Effect of Temperature Gradient on Thick Film Selective Emitter Emittance

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Good, Brian S.; Clark, Eric B.; Chen, Zheng

    1997-01-01

    A temperature gradient across a thick (greater than or equal to .1 mm) film selective emitter will produce a significant reduction in the spectral emittance from the no temperature gradient case. Thick film selective emitters of rare earth doped host materials such as yttrium-aluminum-garnet (YAG) are examples where temperature gradient effects are important. In this paper a model is developed for the spectral emittance assuming a linear temperature gradient across the film. Results of the model indicate that temperature gradients will result in reductions the order of 20% or more in the spectral emittance.

  18. Optical and structural properties of sputtered CdS films for thin film solar cell applications

    SciTech Connect

    Kim, Donguk; Park, Young; Kim, Minha; Choi, Youngkwan; Park, Yong Seob; Lee, Jaehyoeng

    2015-09-15

    Graphical abstract: Photo current–voltage curves (a) and the quantum efficiency (QE) (b) for the solar cell with CdS film grown at 300 °C. - Highlights: • CdS thin films were grown by a RF magnetron sputtering method. • Influence of growth temperature on the properties of CdS films was investigated. • At higher T{sub g}, the crystallinity of the films improved and the grains enlarged. • CdS/CdTe solar cells with efficiencies of 9.41% were prepared at 300 °C. - Abstract: CdS thin films were prepared by radio frequency magnetron sputtering at various temperatures. The effects of growth temperature on crystallinity, surface morphology and optical properties of the films were characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman spectra, UV–visible spectrophotometry, and photoluminescence (PL) spectra. As the growth temperature was increased, the crystallinity of the sputtered CdS films was improved and the grains were enlarged. The characteristics of CdS/CdTe thin film solar cell appeared to be significantly influenced by the growth temperature of the CdS films. Thin film CdS/CdTe solar cells with efficiencies of 9.41% were prepared at a growth temperature of 300 °C.

  19. Selected configuration tradeoffs of contour optical instruments

    NASA Astrophysics Data System (ADS)

    Warren, J.; Strohbehn, K.; Murchie, S.; Fort, D.; Reynolds, E.; Heyler, G.; Peacock, K.; Boldt, J.; Darlington, E.; Hayes, J.; Henshaw, R.; Izenberg, N.; Kardian, C.; Lees, J.; Lohr, D.; Mehoke, D.; Schaefer, E.; Sholar, T.; Spisz, T.; Willey, C.; Veverka, J.; Bell, J.; Cochran, A.

    2003-01-01

    The Comet Nucleus Tour (CONTOUR) is a low-cost NASA Discovery mission designed to conduct three close flybys of comet nuclei. Selected configuration tradeoffs conducted to balance science requirements with low mission cost are reviewed. The tradeoffs discussed focus on the optical instruments and related spacecraft considerations. Two instruments are under development. The CONTOUR Forward Imager (CFI) is designed to perform optical navigation, moderate resolution nucleus/jet imaging, and imaging of faint molecular emission bands in the coma. The CONTOUR Remote Imager and Spectrometer (CRISP) is designed to obtain high-resolution multispectral images of the nucleus, conduct spectral mapping of the nucleus surface, and provide a backup optical navigation capability. Tradeoffs discussed are: (1) the impact on the optical instruments of not using reaction wheels on the spacecraft, (2) the improved performance and simplification gained by implementing a dedicated star tracker instead of including this function in CFI, (3) the improved flexibility and robustness of switching to a low frame rate tracker for CRISP, (4) the improved performance and simplification of replacing a visible imaging spectrometer by enhanced multispectral imaging in CRISP, and (5) the impact on spacecraft resources of these and other tradeoffs.

  20. Optical and Structural Properties of Thin Film Composites.

    NASA Astrophysics Data System (ADS)

    Gibson, Ursula Jane

    This work describes the optical and structural characterization of metal-insulator and bimetallic composite films. Included are experimental details, theoretical descriptions of these systems, and a correlation of the optical response and microstructure of these thin film systems. The films were made by simultaneous or sequential evaporation of the constituents onto either amorphous or single crystal substrates. Two reflectance and one transmittance measurements were combined and inverted to determine the intrinsic optical constants of these materials over the wavelength range 0.2 to 3.0 microns. The metal insulator systems studied were Au-Al(,2)O(,3) and Au-MgO. The optical behavior and transport properties of these materials were measured, and correlated with their disparate microstructures. The optical behavior was compared to the predictions of three effective medium theories, labelled as the Maxwell-Garnett, Bruggeman Self-Consistent and Probabilistic Growth theories. The differing topological assumptions which form the bases of these theories were correlated with microscopic examination of the morphologies of the films, and it was found that the simple theories adequately predicted the optical response of the composites. Bimetallic systems were also studied, to investigate the extension of the Bruggeman theory to symmetric composites of immiscible metal constituents. It was found that the theory adequately predicts the behavior of films which display the symmetric morphology assumed by the theory. Studies of non-symmetric composites, and anisotropic systems (such as epitaxial layered materials (ELMs), showed that the symmetric morphology is necessary in order to model these systems with the Bruggeman theory.

  1. Molecular Optics Nonlinear Optical Processes in Organic and Polymeric Crystals and Films

    DTIC Science & Technology

    1988-04-01

    LAr 9B L Appr 1~ forjIbi1893 2 8 I I IE2 Molecular Optics: Nonlinear Optical Processes in Organic and Polymeric Crystals and Films i Professor A. F...frequency dependent local field factors. While there are various prevalent models (Lorentz- Lorenz, Onsager ) all of them give the field factors in terms of

  2. Optical and structural properties of zinc iodine thin films

    NASA Astrophysics Data System (ADS)

    Kariper, İ. A.

    2015-06-01

    Zinc iodide (ZnI2) crystalline thin film is produced with chemical bath deposition on substrates (commercial glass). The pH of chemical bath is scanned with controlled potassium hydroxide. Some properties of films changed with pH and changes of pH were analyzed. The pH values are scanned at 6.01-6.29. Transmittance, absorption, optical band gap and refractive index are investigated by UV/Vis. spectrum. The hexagonal and tetragonal form in structural properties in XRD at pH: 6.01 were seen. The pH of bath was up to 6.01, KZnI3ṡ2H2O (orthorhombic), KZnI3ṡ(H2O)2 (orthorhombic), ZnI2 (tetragonal) and ZnI2 (hexagonal) forms were observed in XRD patterns. The structural and optical properties of ZnI2 thin films analyzed at different pH. SEM analysis studied for surface analysis in films. The SEM analyses were agreed with XRD patterns. The optical band gap increased with pH between 3.4 and 3.6 eV. The film thickness changed with pH at 108-345 nm. Also refractive index and transmission generally increased with pH.

  3. Velocity selective optical pumping resonance sign reversal

    NASA Astrophysics Data System (ADS)

    Krasteva, A.; Slavov, D.; Todorov, G.; Cartaleva, S.

    2013-03-01

    We report experimental and theoretical examinations of the peculiarities in Velocity Selective Optical Pumping (VSOP) resonance behavior at open and closed hyperfine transition spectra of Cs atoms (on the D2 line), confined in optical cell with thickness L = 6λ, where λ = 852 nm. For linear and circular polarizations of the irradiating light, open transitions exhibit reduced absorption (fluorescence) VSOP resonances whose contrast increases with atomic concentration and light intensity. However, in case of closed transition the situation is different, the enhanced absorption (fluorescence) VSOP resonance reverses its sign with the atomic concentration and light intensity. Theoretical analysis based on the density matrix formalism, taking into account the statistical tensors describing atomic population and longitudinal alignment, shows that the VSOP resonance sign reversal at the closed transition can be attributed to the efficiency reduction of population transfer by the spontaneous decay with atomic source temperature.

  4. Fibre Optic Sensors for Selected Wastewater Characteristics

    PubMed Central

    Chong, Su Sin; Abdul Aziz, A. R.; Harun, Sulaiman W.

    2013-01-01

    Demand for online and real-time measurements techniques to meet environmental regulation and treatment compliance are increasing. However the conventional techniques, which involve scheduled sampling and chemical analysis can be expensive and time consuming. Therefore cheaper and faster alternatives to monitor wastewater characteristics are required as alternatives to conventional methods. This paper reviews existing conventional techniques and optical and fibre optic sensors to determine selected wastewater characteristics which are colour, Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD). The review confirms that with appropriate configuration, calibration and fibre features the parameters can be determined with accuracy comparable to conventional method. With more research in this area, the potential for using FOS for online and real-time measurement of more wastewater parameters for various types of industrial effluent are promising. PMID:23881131

  5. Selected Instrumentation Films, 1969-1970.

    ERIC Educational Resources Information Center

    Simmons, Raymond L., Ed.

    This list of currently available films and filmstrips pertinent to instrumentation has been compiled from information solicited from many government and private sources. The 1969 compilation has been organized into the following eight categories: (1) principles of measurement and basic measurements; (2) analysis instrumentation; (3) automation and…

  6. Selected Instrumentation Films, 1969-1970.

    ERIC Educational Resources Information Center

    Simmons, Raymond L., Ed.

    This list of currently available films and filmstrips pertinent to instrumentation has been compiled from information solicited from many government and private sources. The 1969 compilation has been organized into the following eight categories: (1) principles of measurement and basic measurements; (2) analysis instrumentation; (3) automation and…

  7. Films on the Future: A Selective Listing.

    ERIC Educational Resources Information Center

    Martin, Marie

    This annotated list of films focuses on fourteen subject areas: 1) Atomic Energy/Fuel/Power; 2) Automation/Computer/Data Processing; 3) Biochemical Research/Behavioral Sciences; 4) Communications/Transportation; 5) Concepts; 6) Ecology/Pollution/Weather Modification; 7) Education; 8) Food/Population Control; 9) Ocean/Ocean Sciences; 10)…

  8. Films on the Future: A Selective Listing.

    ERIC Educational Resources Information Center

    Martin, Marie

    This annotated list of films focuses on fourteen subject areas: 1) Atomic Energy/Fuel/Power; 2) Automation/Computer/Data Processing; 3) Biochemical Research/Behavioral Sciences; 4) Communications/Transportation; 5) Concepts; 6) Ecology/Pollution/Weather Modification; 7) Education; 8) Food/Population Control; 9) Ocean/Ocean Sciences; 10)…

  9. Optical Thin Film Modeling: Using FTG's FilmStar Software

    NASA Technical Reports Server (NTRS)

    Freese, Scott

    2009-01-01

    Every material has basic optical properties that define its interaction with light: The index of refraction (n) and extinction coefficient (k) vary for the material as a function of the wavelength of the incident light. Also significant are the phase velocity and polarization of the incident light These inherent properties allow for the accurate modeling of light s behavior upon contact with a surface: Reflectance, Transmittance, Absorptance.

  10. Multifunctional plasmonic film for recording near-field optical intensity.

    PubMed

    Roxworthy, Brian J; Bhuiya, Abdul M; Inavalli, V V G Krishna; Chen, Hao; Toussaint, Kimani C

    2014-08-13

    We demonstrate the plasmonic equivalent of photographic film for recording optical intensity in the near field. The plasmonic structure is based on gold bowtie nanoantenna arrays fabricated on SiO2 pillars. We show that it can be employed for direct laser writing of image data or recording the polarization structure of optical vector beams. Scanning electron micrographs reveal a careful sculpting of the radius of curvature and height of the triangles composing the illuminated nanoantennas, as a result of plasmonic heating, that permits spatial tunability of the resonance response of the nanoantennas without sacrificing their geometric integrity. In contrast to other memory-dedicated approaches using Au nanorods embedded in a matrix medium, plasmonic film can be used in multiple application domains. To demonstrate this functionality, we utilize the structures as plasmonic optical tweezers and show sequestering of SiO2 microparticles into optically written channels formed between exposed sections of the film. The plasmonic film offers interesting possibilities for photonic applications including optofluidic channels "without walls," in situ tailorable biochemical sensing assays, and near-field particle manipulation and sorting.

  11. Optical and electrochemical properties of optically transparent, boron-doped diamond thin films deposited on quartz.

    PubMed

    Stotter, Jason; Zak, Jerzy; Behler, Zack; Show, Yoshiuki; Swain, Greg M

    2002-12-01

    The optical and electrochemical properties of transparent, boron-doped diamond thin film, deposited on quartz, are discussed. The films were deposited by microwave-assisted chemical vapor deposition, for 1-2 h, using a 0.5% CH4/H2 source gas mixture at 45 Torr and 600 W of power. A high rate of diamond nucleation was achieved by mechanically scratching the quartz. This pretreatment leads to the formation of a continuous film, in a short period of time, which consists of nanometer-sized grains of diamond. The thin-film electrode was characterized by cyclic voltammetry, atomic force microscopy, and UV-visible absorption spectrophotometry. The film's electrochemical response was evaluated using Ru(NH3)6(3+/2+) in 1 M KCl, Fe(CN)6(3-/4-) in 1 M KCl, and chlorpromazine (CPZ) in 10 mM HClO4. The film exhibited a low voltammetric background current and a stable and active voltammetric response for all three redox systems. The optical transparency of the polycrystalline film in the visible region was near 50% and fairly constant between 300 and 800 nm. The optical and electrical properties were extremely stable during 48-h exposure tests in various aqueous (HNO3, NaOH) solutions and nonaqueous (e.g., chlorinated) solvents. The properties were also extremely stable during anodic and cathodic potential cycling in harsh aqueous environments. This stability is in stark contrast to what was observed for an indium-doped tin oxide thin film coated on quartz. The spectroelectrochemical response (transmission mode) for CPZ was studied in detail, using a thin-layer spectroelectrochemical cell. Thin-layer voltammetry, potential step/ absorption measurements, and detection analytical figures of merit are presented. The results demonstrate that durable, stable, and optically transparent diamond thin films, with low electrical resistivity (approximately 0.026 omega x cm) laterally through the film, can be deposited on quartz.

  12. Structural and optical properties of distyrylbenzene derivative thin films

    NASA Astrophysics Data System (ADS)

    Ni, J. P.; Ueda, Y.; Hanada, T.; Takada, N.; Ichino, Y.; Yoshida, Y.; Tanigaki, N.; Yase, K.; Wang, D. K.; Wang, F. S.

    1999-12-01

    In order to understand the relationship between the molecular orientation and optical properties of oligophenylenevinylene film, oriented thin films of 1,4-di(p-methoxystyryl)benzene (DSB-1) and 1,4-di(p-methoxystyryl)-2,5-dimethoxybenzene (DSB-2) were fabricated on a potassium bromide (KBr) (001) surface by the vacuum-evaporation method. The structures and optical properties of DSB films have been investigated by transmission electron microscopy (TEM), atomic force microscopy (AFM) and polarized photoluminescence (PL) spectroscopy, respectively. DSB-1 molecules orient obliquely and/or parallel to the substrate surface depending on the substrate temperature. On the other hand, DSB-2 molecules tend to grow epitaxially with the molecular plane parallel to the substrate surface. The anisotropic molecular orientations represent the polarized PL. The epitaxial growth and molecular orientations observed by TEM and AFM at the local and microscopic scale are confirmed by polarized PL measurement on a macroscopic scale.

  13. Optical properties of hydroxyethyl cellulose film treated with nitrogen plasma

    NASA Astrophysics Data System (ADS)

    Mahmoud, K. H.

    2016-03-01

    Hydroxyethyl cellulose (HEC) film has been prepared by casting technique. The prepared sample has been treated with nitrogen plasma at different exposure times. The optical absorption was recorded at room temperature in the wavelength range of 200-800 nm. Absorbance fitting procedure curves revealed a direct allowed transition with optical band gap, Eopt, of 4.9 eV for pristine film, and this value decreases to 4.30 eV for 20 min plasma treatment time. The band tail values (Ee) were found to be increased under plasma time treatment from 1.74 eV in case of the pristine film to 2.20 eV for 20 min. The dispersion of refractive index and complex dielectric constants under plasma treatment was also studied. Variation of color parameters under effect of the plasma treatment is analyzed in the framework of CIE L*U*V* color space.

  14. Fast Industrial Inspection of Optical Thin Film Using Optical Coherence Tomography.

    PubMed

    Shirazi, Muhammad Faizan; Park, Kibeom; Wijesinghe, Ruchire Eranga; Jeong, Hyosang; Han, Sangyeob; Kim, Pilun; Jeon, Mansik; Kim, Jeehyun

    2016-09-28

    An application of spectral domain optical coherence tomography (SD-OCT) was demonstrated for a fast industrial inspection of an optical thin film panel. An optical thin film sample similar to a liquid crystal display (LCD) panel was examined. Two identical SD-OCT systems were utilized for parallel scanning of a complete sample in half time. Dual OCT inspection heads were utilized for transverse (fast) scanning, while a stable linear motorized translational stage was used for lateral (slow) scanning. The cross-sectional and volumetric images of an optical thin film sample were acquired to detect the defects in glass and other layers that are difficult to observe using visual inspection methods. The rapid inspection enabled by this setup led to the early detection of product defects on the manufacturing line, resulting in a significant improvement in the quality assurance of industrial products.

  15. Fast Industrial Inspection of Optical Thin Film Using Optical Coherence Tomography

    PubMed Central

    Shirazi, Muhammad Faizan; Park, Kibeom; Wijesinghe, Ruchire Eranga; Jeong, Hyosang; Han, Sangyeob; Kim, Pilun; Jeon, Mansik; Kim, Jeehyun

    2016-01-01

    An application of spectral domain optical coherence tomography (SD-OCT) was demonstrated for a fast industrial inspection of an optical thin film panel. An optical thin film sample similar to a liquid crystal display (LCD) panel was examined. Two identical SD-OCT systems were utilized for parallel scanning of a complete sample in half time. Dual OCT inspection heads were utilized for transverse (fast) scanning, while a stable linear motorized translational stage was used for lateral (slow) scanning. The cross-sectional and volumetric images of an optical thin film sample were acquired to detect the defects in glass and other layers that are difficult to observe using visual inspection methods. The rapid inspection enabled by this setup led to the early detection of product defects on the manufacturing line, resulting in a significant improvement in the quality assurance of industrial products. PMID:27690043

  16. Optical Logarithmic Transformation of Speckle Images with Bacteriorhodopsin Films

    NASA Technical Reports Server (NTRS)

    Downie, John D.

    1995-01-01

    The application of logarithmic transformations to speckle images is sometimes desirable in converting the speckle noise distribution into an additive, constant-variance noise distribution. The optical transmission properties of some bacteriorhodopsin films are well suited to implement such a transformation optically in a parallel fashion. I present experimental results of the optical conversion of a speckle image into a transformed image with signal-independent noise statistics, using the real-time photochromic properties of bacteriorhodopsin. The original and transformed noise statistics are confirmed by histogram analysis.

  17. Optical properties of amorphous Se films prepared by PECVD

    NASA Astrophysics Data System (ADS)

    Nagels, P.; Sleeckx, E.; Callaerts, R.; Márquez, E.; González, J. M.; Bernal-Oliva, A. M.

    1997-05-01

    The optical transmission spectrum of amorphous Se films prepared by plasma-enhanced chemical vapour deposition was measured over the 500 to 2000 nm spectral region. The absorption coefficient values plotted vs photon energy according to Tauc's law yielded an optical gap, Eg, of 1.94 eV. The temperature dependence of Eg was measured between 13 K and 300 K and was found to be well described within Fan's one-phonon approximation. Photo-induced darkening of the optical gap was studied by illumination at 13 K and 77 K.

  18. Design of Gradient Index Optical Thin Films

    DTIC Science & Technology

    1996-06-12

    and height of the notch controlled by five parameters. More complicated rugate films are created by adding several basic rugates in parallel or in...electric field aligned perpendicular to the plane of incidence, and the transverse magnetic (TM) case, which has its electric field aligned parallel to...from Stephen Decatur High School in Decatur, Illinois in 1981, and continued his education at the Univesity of Illinois a Urbana, Illinois

  19. Annealing Effects on Structure and Optical Properties of Diamond-Like Carbon Films Containing Silver.

    PubMed

    Meškinis, Šarūnas; Čiegis, Arvydas; Vasiliauskas, Andrius; Šlapikas, Kęstutis; Gudaitis, Rimantas; Yaremchuk, Iryna; Fitio, Volodymyr; Bobitski, Yaroslav; Tamulevičius, Sigitas

    2016-12-01

    In the present study, diamond-like carbon films with embedded Ag nanoparticles (DLC:Ag) were deposited by reactive magnetron sputtering. Structure of the films was investigated by Raman scattering spectroscopy. Atomic force microscopy was used to define thickness of DLC:Ag films as well as to study the surface morphology and size distribution of Ag nanoparticles. Optical absorbance and reflectance spectra of the films were studied in the 180-1100-nm range. Air annealing effects on structure and optical properties of the DLC:Ag were investigated. Annealing temperatures were varied in the 180-400 °C range. Changes of size and shape of the Ag nanoclusters took place due to agglomeration. It was found that air annealing of DLC:Ag films can result in graphitization following destruction of the DLC matrix. Additional activation of surface-enhanced Raman scattering (SERS) effect in DLC:Ag films can be achieved by properly selecting annealing conditions. Annealing resulted in blueshift as well as significant narrowing of the plasmonic absorbance and reflectance peaks. Moreover, quadrupole surface plasmon resonance peaks appeared. Modeling of absorption spectra of the nanoclusters depending on the shape and surrounding media has been carried out.

  20. Extraordinary optical transmission through nonlocal holey metal films

    NASA Astrophysics Data System (ADS)

    David, Christin; Christensen, Johan

    2017-06-01

    We investigate nonlocal electrodynamics based on the generalized hydrodynamic approach including electron diffusion in holey gold films, showing extraordinary optical transmission (EOT). Dramatic changes with respect to the local approximation for rather large film thicknesses t ≲ 100 nm impact both reflectance and absorbance at normal incidence. Beyond the familiar resonance blueshift with the decreasing film thickness, the interference of longitudinal pressure waves in the holey structure generates an unexpected oscillatory response with geometrical parameters. An increase in the transmittance relative to the local result of up to 33% (typically up to ± 6 % at resonance) was observed, but it can also be suppressed when absorption dominates. We expect that our findings will stimulate additional studies of EOT when taking into consideration nonlocal effects in holey films of experimentally accessible parameters in two-dimensional hole arrays.

  1. A film pressure sensor based on optical fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Zhang, Zhichun; Deng, Gang; Dai, Yongbo; Liu, Yanju; Leng, Jinsong

    2010-03-01

    The measurement of pressure is essential for the design and flying controlling of aircraft. In order to measure the surface pressures of the aircraft, the common pressure tube method and Pressure sensitive paint measurement method have their own disadvantages, and are not applicable to all aircraft structures and real time pressure monitoring. In this paper, a novel thin film pressure sensor based on Fiber Bragg Grating (FBG) is proposed, using FBG measuring the tangential strain of the disk sensing film. Theoretical circle strain of the disk sensing film of the pressure sensor under pressure and temperature variation are analyzed, and the linear relationship between FBG center wavelength shift and pressure, temperature variation is gotten. The pressure and temperature calibration experiments prove the theoretical analysis. But the calibration sensing parameters are small than the calculating ones, which is caused by the constraint of optical fibre to the thin sensing film.

  2. Optical spectra of graded nanostructured TiO 2 chiral sculptured thin films

    NASA Astrophysics Data System (ADS)

    Babaei, F.; Esfandiar, A.; Savaloni, H.

    2010-07-01

    The optical properties of graded chiral sculptured TiO 2 thin films in axial and non-axial excited states are calculated using the rigorous coupled wave analysis method (RCWA) in conjunction with the Bruggeman homogenization formalism. The filtering frequency and polarization selectivity of these graded nanostructured TiO 2 sculptured thin films showed dependence on both structural and deposition parameters. The results achieved are consistent with the experimental data [K. M. Krause and M. J. Bret, Adv. Funct. Mater. 18 (2008) 3111].

  3. Theoretical and experimental optical studies of cholesteric liquid crystal films with thermally induced pitch gradients.

    PubMed

    Zografopoulos, Dimitrios C; Kriezis, Emmanouil E; Mitov, Michel; Binet, Corinne

    2006-06-01

    The reflection properties of cholesteric films with thermally induced pitch gradients are theoretically and experimentally studied. It is shown that the optical behavior of such films corresponds to the averaged contribution of a number of stochastic pitch variation profiles, due to the transversal and longitudinal nonuniformities that develop in the helical structure of such samples. Depending on the annealing time, both narrow-band and broadband behavior can be selectively achieved. The influence of the pitch profile gradient on the broadband reflection performance of cholesteric samples is theoretically analyzed, and a multi-slab structure for achieving optimum efficiency is proposed.

  4. Simultaneous Chemical and Optical Patterning of Polyacrylonitrile Film by Vapor-Based Reaction.

    PubMed

    Shin, Jae-Won; Lee, Choonghyeon; Cha, Sang-Ho; Jang, Jyongsik; Lee, Kyung Jin

    2015-06-01

    The surface of polyacrylonitrile (PAN) film is treated with ethyleneamines (EDA) in a simple chemical vapor phase reaction. Successful introduction of amine functional groups on the cyano group of PAN backbone is verified by FT-IR and NMR measurements. Further UV-vis and photoluminescence analyses show a red shift of the emission peak after repeated EDA treatment, which might be attributed to the formation of imine conjugation from newly formed carbon-nitrogen bonds on the PAN backbone. Further confocal laser scanning microscopy reveals that selective patterning of EDA on PAN films is possible via local polydimethylsiloxane masking. The results indicate that both chemical and optical patterning on PAN film can be realized via a single reaction and show the potential of this novel methodology in selective patterning. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Nanocomposite thin films for optical temperature sensing

    DOEpatents

    Ohodnicki, Jr., Paul R.; Brown, Thomas D.; Buric, Michael P.; Matranga, Christopher

    2017-02-14

    The disclosure relates to an optical method for temperature sensing utilizing a temperature sensing material. In an embodiment the gas stream, liquid, or solid has a temperature greater than about 500.degree. C. The temperature sensing material is comprised of metallic nanoparticles dispersed in a dielectric matrix. The metallic nanoparticles have an electronic conductivity greater than approximately 10.sup.-1 S/cm at the temperature of the temperature sensing material. The dielectric matrix has an electronic conductivity at least two orders of magnitude less than the dispersed metallic nanoparticles at the temperature of the temperature sensing material. In some embodiments, the chemical composition of a gas stream or liquid is simultaneously monitored by optical signal shifts through multiple or broadband wavelength interrogation approaches. In some embodiments, the dielectric matrix provides additional functionality due to a temperature dependent band-edge, an optimized chemical sensing response, or an optimized refractive index of the temperature sensing material for integration with optical waveguides.

  6. System for measuring optical admittance of a thin film stack

    NASA Astrophysics Data System (ADS)

    Chen, Sheng-Hui; Wu, Kai; Kuo, Chien-Cheng; Ma, Sheng-Ju; Lee, Cheng-Chung

    2009-07-01

    A new method based on the polarization interferometer structure has been applied to measure the optical admittance, the refractive index and thickness of a thin film. The structure is a vibration insensitive optical system. There is one Twyman-Green interferometer part to induce a phase difference and one Fizeau interferometer part to induce the interference in the system. The intensities coming from four different polarizers were measured at the same time to prevent mechanical vibration influence. Using the polarization interferometer, the optical admittance, the refractive index and thickness of a single layer of Ta2O5 thin film has been measured. The measurement results were compared with the results obtained by ellipsometer. The results meet reasonable values in both refractive index and thickness.

  7. Enhanced optical response of hybridized VO₂/graphene films.

    PubMed

    Kim, Hyeongkeun; Kim, Yena; Kim, TaeYoung; Jang, A-Rang; Jeong, Hu Young; Han, Seung Ho; Yoon, Dae Ho; Shin, Hyeon Suk; Bae, Dong Jae; Kim, Keun Soo; Yang, Woo Seok

    2013-04-07

    Application of graphene as transparent electrodes is an active research area due to its excellent electrical and optical properties. Vanadium dioxide (VO2) is an attractive material since it is a thermochromic material that undergoes a structural phase transition when heat is applied. The phase transition results in the change of electrical and optical characteristics. We report optical characteristics of hybrid materials of graphene and VO2. We observed a 12% improvement in infrared transmittance with VO2 films deposited on graphene sapphire substrates compared to that of bare sapphire substrates. We also found that the phase transition temperature decreases as the number of graphene layers on the substrates increases. In the case of VO2 films on the substrate that was coated with four layers of graphene, the mean phase transition temperature was lowered to ∼56 °C.

  8. Selective and differential optical spectroscopies in photosynthesis.

    PubMed

    Krausz, Elmars

    2013-10-01

    Photosynthetic pigments are inherently intense optical absorbers and have strong polarisation characteristics. They can also luminesce strongly. These properties have led optical spectroscopies to be, quite naturally, key techniques in photosynthesis. However, there are typically many pigments in a photosynthetic assembly, which when combined with the very significant inhomogeneous and homogeneous linewidths characteristic of optical transitions, leads to spectral congestion. This in turn has made it difficult to provide a definitive and detailed electronic structure for many photosynthetic assemblies. An electronic structure is, however, necessary to provide a foundation for any complete description of fundamental processes in photosynthesis, particularly those in reaction centres. A wide range of selective and differential spectral techniques have been developed to help overcome the problems of spectral complexity and congestion. The techniques can serve to either reduce spectral linewidths and/or extract chromophore specific information from unresolved spectral features. Complementary spectral datasets, generated by a number of techniques, may then be combined in a 'multi-dimensional' theoretical analysis so as to constrain and define effective models of photosynthetic assemblies and their fundamental processes. A key example is the work of Renger and his group (Raszewski, Biophys J 88(2):986-998, 2005) on PS II reaction centre assemblies. This article looks to provide an overview of some of these techniques and indicate where their strengths and weaknesses may lie. It highlights some of our own contributions and indicates areas where progress may be possible.

  9. Enhanced optical response of hybridized VO2/graphene films

    NASA Astrophysics Data System (ADS)

    Kim, Hyeongkeun; Kim, Yena; Kim, Taeyoung; Jang, A.-Rang; Jeong, Hu Young; Han, Seung Ho; Yoon, Dae Ho; Shin, Hyeon Suk; Bae, Dong Jae; Kim, Keun Soo; Yang, Woo Seok

    2013-03-01

    Application of graphene as transparent electrodes is an active research area due to its excellent electrical and optical properties. Vanadium dioxide (VO2) is an attractive material since it is a thermochromic material that undergoes a structural phase transition when heat is applied. The phase transition results in the change of electrical and optical characteristics. We report optical characteristics of hybrid materials of graphene and VO2. We observed a 12% improvement in infrared transmittance with VO2 films deposited on graphene sapphire substrates compared to that of bare sapphire substrates. We also found that the phase transition temperature decreases as the number of graphene layers on the substrates increases. In the case of VO2 films on the substrate that was coated with four layers of graphene, the mean phase transition temperature was lowered to ~56 °C.Application of graphene as transparent electrodes is an active research area due to its excellent electrical and optical properties. Vanadium dioxide (VO2) is an attractive material since it is a thermochromic material that undergoes a structural phase transition when heat is applied. The phase transition results in the change of electrical and optical characteristics. We report optical characteristics of hybrid materials of graphene and VO2. We observed a 12% improvement in infrared transmittance with VO2 films deposited on graphene sapphire substrates compared to that of bare sapphire substrates. We also found that the phase transition temperature decreases as the number of graphene layers on the substrates increases. In the case of VO2 films on the substrate that was coated with four layers of graphene, the mean phase transition temperature was lowered to ~56 °C. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr34054f

  10. New insights on electro-optical response of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) film to humidity

    DOE PAGES

    Muckley, Eric S.; Univ. of Tennessee, Knoxville, TN; Jacobs, Christopher B.; ...

    2017-04-26

    Understanding the relative humidity (RH) response of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is critical for improving the stability of organic electronic devices and developing selective sensors. In this work combined gravimetric sensing, nanoscale surface probing, and mesoscale optoelectronic characterization are used to directly compare the RH dependence of electrical and optical conductivities and unfold connections between the rate of water adsorption and changes in functional properties of PEDOT:PSS film. We report three distinct regimes where changes in electrical conductivity, optical conductivity, and optical bandgap are correlated with the mass of adsorbed water. At low (RH < 25%) and high (RH > 60%) humiditymore » levels dramatic changes in electrical, optical and structural properties occur, while changes are insignificant in mid-RH (25% < RH < 60%) conditions. We associate the three regimes with water adsorption at hydrophilic moieties at low RH, diffusion and swelling throughout the film at mid-RH, and saturation of the film by water at high RH. Optical film thickness increased by 150% as RH was increased from 9% to 80%. Low frequency (1 kHz) impedance increased by ~100% and film capacitance increased by ~30% as RH increased from 9% to 80% due to an increase in the film dielectric constant. Finally, changes in electrical and optical conductivities concomitantly decrease across the full range of RH tested.« less

  11. Structural, optical and nonlinear optical studies of AZO thin film prepared by SILAR method for electro-optic applications

    NASA Astrophysics Data System (ADS)

    Edison, D. Joseph; Nirmala, W.; Kumar, K. Deva Arun; Valanarasu, S.; Ganesh, V.; Shkir, Mohd.; AlFaify, S.

    2017-10-01

    Aluminium doped (i.e. 3 at%) zinc oxide (AZO) thin films were prepared by simple successive ionic layer adsorption and reaction (SILAR) method with different dipping cycles. The structural and surface morphology of AZO thin films were studied by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical parameters such as, transmittance, band gap, refractive index, extinction coefficient, dielectric constant and nonlinear optical properties of AZO films were investigated. XRD pattern revealed the formation of hexagonal phase ZnO and the intensity of the film was found to increase with increasing dipping cycle. The crystallite size was found to be in the range of 29-37 nm. Scanning Electron Microscope (SEM) images show the presence of small sized grains, revealing that the smoothest surface was obtained at all the films. The EDAX spectrum of AZO conforms the presence of Zn, O and Al. The optical transmittance in the visible region is high 87% and the band gap value is 3.23 eV. The optical transmittance is decreased with respect to dipping cycles. The room temperature PL studies revealed that the AZO films prepared at (30 cycles) has good film quality with lesser defect density. The third order nonlinear optical parameters were also studied using Z-scan technique to know the applications of deposited films in nonlinear devices. The third order nonlinear susceptibility value is found to be 1.69 × 10-7, 3.34 × 10-8, 1.33 × 10-7and 2.52 × 10-7 for AZO films deposited after 15, 20, 25 and 30 dipping cycles.

  12. Multifunctional sensing film used for fiber optic cholesterol sensor

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Huang, Jun; Li, Mingtian; Zhou, Xuan

    2008-12-01

    In this paper, by using ethyl silicate, ethanol and fluorescence indicator as the precursors, the multifunctional optic biosensing (MOBS) film containing cholesterol oxidase and the fluorescence indicator was prepared by sol-gel method. This biosensing film has both the function of biocatalyst and oxygen biosensing and can be used as the effective biosensing materials for fiber optic cholesterol sensor. The fiber optical cholesterol sensor based on fluorescence quenching was designed and fabricated using lock-in amplifying technology to realize the detection of cholesterol concentration. The experimental results showed that the best precursor proportion in volume ratio is: ethyl silicate: ethanol: 0.01 M HCl = 5: 8: 1.6. The drying rate of the sol could be controlled by using formamide as the controlling drier. When 16% of formamide were added in the mixing system, the cracks of the film could be reduced greatly and the immobilization of cholesterol oxidase and the fluorescence indicator could be improved effectively. A linear relationship between phase delay φ and the cholesterol concentration was observed in the range of 100 to 500 mg/dL. Since the cholesterol concentration is in the range of 140 to 200 mg/dL in the blood of healthy people, it will be possible for the sensor to be used in clinical detection. The biosensor with MOBS film has the response time of about 30 s, which is rather fast for a biosensor, and the relative deviation of +/-5.03%. This biosensor also has good stability.

  13. Optical buffer films for high-speed interferometric imaging

    NASA Astrophysics Data System (ADS)

    Lysogorski, Charles D.

    1995-02-01

    To understand wind tunnel flow-field turbulence, it is necessary to understand how high speed (kHz) transient events develop in time. The framing rates necessary to record such imagery are too high for conventional video camera systems to be used. While high-speed, film-based cameras (e.g. Cordin drum film recorders) have sufficient spatial resolution and framing rates, analyzing the data acquired with these cameras is time consuming, possibly taking days to process and digitize the film images. These limitations in existing digital imaging technologies, and pulsed flow-field illumination systems have prevented digital movies of phenomena in turbulent and unstable flow-field regions to be made with sufficient spatial and temporal resolution. To address this need, I am presenting two techniques which can record data onto an intermediate optical buffer with the desired temporal and spatial resolution. These optical buffers incorporate real-time erasable recording film which consist of a phosphor or bacteriorhodopsin (BR) that would be used to temporarily store the images which were recorded at kHz rates. These images are then reconstructed and digitized at standard video rates, and stored on an optical disk. The primary advantage of this technique is in the ability to record images at extremely fast rates (60 kHz or faster) and then digitize the images at standard video recording rates.

  14. Optically transparent and electrically conducting epitaxial Ta2O films

    NASA Astrophysics Data System (ADS)

    Gnanarajan, S.; Lam, S. K. H.; Foley, C. P.

    2007-03-01

    An optically transparent and electrically conducting oxide Ta2O epitaxial thin film has been fabricated and characterized. In our experiments, we grew epitaxial Ta films on r-cut sapphire crystal substrates, which were subsequently oxidized into Ta2O films. The x-ray θ-2θ scan peaks match the American Society for Testing and Materials x-ray powder data card for Ta2O (18-1302) with a cubic structure. The x-ray photoelectron spectroscopic measurements indicated Ta 4f peak energy values between those for Ta and TaO whereas the O /Ta atomic ratio is between 0.5 and 1. Resistivity-temperature measurements showed a metallic behavior with resistivity values in the range of (1.5-3.3)×10-4Ωcm at 293K. Optical measurements on 25-100nm thick films indicated that they are transparent in the range of 400-2000nm and have an energy band gap between 2.04 and 2.17eV. The Hall mobility and carrier density of the films were in the range of 62-110cm2V-1s-1 and (1.9-3.0)×1020cm-3, respectively.

  15. Chiral habit selection on nanostructured epitaxial quartz films.

    PubMed

    Carretero-Genevrier, Adrián; Gich, Martí; Picas, Laura; Sanchez, Clément; Rodriguez-Carvajal, Juan

    2015-01-01

    Understanding the crystallization of enantiomorphically pure systems can be relevant to diverse fields such as the study of the origins of life or the purification of racemates. Here we report on polycrystalline epitaxial thin films of quartz on Si substrates displaying two distinct types of chiral habits that never coexist in the same film. We combine Atomic Force Microscopy (AFM) analysis and computer-assisted crystallographic calculations to make a detailed study of these habits of quartz. By estimating the surface energies of the observed crystallites we argue that the films are enantiomorphically pure and we briefly outline a possible mechanism to explain the habit and chiral selection in this system.

  16. Possibilities Of Optically Non Linear Thin Films

    NASA Astrophysics Data System (ADS)

    De Micheli, Marc; Zyss, Joseph; Azema, Alain

    1983-11-01

    Efficient integrated frequency doubling devices transparent in the visible and near I.R. are demanded by a number of applications. The optimization of both wave interaction configurations and material intrinsic nonlinear susceptibility are successively discussed within this scope. Basic features such as power confinement, interaction length dependence, phase matching techniques, underlying the second harmonic generation conversion rate in bulk and waveguided structures are compared. Undoped Ga As film epitaxied over n+ doped Ga As substrate and TIPE Lithium Lobate waveguides exemplify the possibilities of non linear thin films. The higher non linear susceptibility of certain organic molecular single crys-tals should help raise the efficiency of doubling devices. We report the definition and bulk performances of two non linear organic crystals, namely POM (3-methyl-4 nitropyridine-1-oxyde) and MAP (methyl-(2,4-dinitropheny1)-aminopropanoate) with a figure of merit up to one order of magnitude above that of Li Nb 03. The combination of organic materials and waveguided configuration should lead to a new generation of non linear devices.

  17. Optical monitoring of thin oil film thickness in extrusion processes

    NASA Astrophysics Data System (ADS)

    Bogdanowicz, Robert; Wroczyński, Piotr; Graczyk, Jan; Gnyba, Marcin

    2005-09-01

    We have used reflectance spectroscopy for the in-situ, non-invasive monitoring of a thin oil film thickness during extrusion process of ceramic paste in capillary rheometer. Investigated pastes are disperse solid liquid systems prepared from the silicone oil AK106 (Wacker) and ceramic powder AlOOH. The thin oil film, extracted from the extruded paste, appears on walls of the rheometer die. A borosilicate view-port-glass provides optical access to the thin film inside the die. Reflectance spectroscopy enables the thin film thickness measurements by wideband spectral analysis of light back reflected from the sample. This spectrum includes extremes, which results from interference between beams reflected from glass-oil boundary and oil-paste boundary. Position and intensity of this extremes were determined by thickness of the thin film as well as refractive indices of the oil and the paste. Optoelectronic system dedicated for process monitoring by means of reflectance spectroscopy had been designed and built. The system comprises tungsten halogen lamp and fiber optic spectrometer. Optical signals are transmitted through bifurcated fibers, focusing optics and the view-port-window. Spectroscopic monitoring was carried out in VIS-NIR range from 400 to 900 nm as a function of extrusion velocity (0.01-5mm/s) and paste particle granulation (5-20 μm). Computer calculation, performed using dedicated software, enables fast determination of thickness even for reflectance spectra interfered by high noise level. Fast development of ceramic components technology requires detailed description of complex rheometric processes. Monitoring of the most important process parameter - oil layer thickness - enables pre-determination of rheometric factors required for proper paste extrusion and accurate shape filling.

  18. Application of thin dielectric films in low coherence fiber-optic Fabry-Pérot sensing interferometers: comparative study

    NASA Astrophysics Data System (ADS)

    Hirsch, Marzena; Wierzba, Paweł; Jedrzejewska-Szczerska, Małgorzata

    2016-11-01

    We examine the application of selected thin dielectric films, deposited by atomic layer deposition (ALD), in a low coherence fiber-optic Fabry-Pérot interferometer designed for sensing applications. Such films can be deposited on the end-face of a single mode optical fiber (SMF-28) in order to modify the reflectivity of the Fabry-Pérot cavity, to provide protection of the fibers from aggressive environments or to create a multi-cavity interferometric sensor. Spectral reflectance of films made from zinc oxide (ZnO), titanium dioxide (TiO2), aluminum oxide (Al2O3) and boron nitride (BN) was calculated for various thickness of the films and compared. The results show that the most promising materials for use in fiber-optic Fabry-Pérot interferometer are TiO2 and ZnO, although Al2O3 is also suitable for this application.

  19. Selectively driving optical magnetism (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Scherer, Norbert F.; Manna, Uttam; Parker, John A.; lee, Jung-Hoon; Deng, Tiansong; Shepherd, Nolan; Weizmann, Yossef

    2016-09-01

    It is well known that one can create a magnetic field by passing a DC or AC electric current through a coil of conductor (i.e., a wire); a phenomenon described by the Maxwell-Faraday's law of electromagnetic induction. NMR or ESR (nuclear magnetic resonance or electron spin resonance) spectroscopies involve the interaction of a spin (nuclear or electron, respectively) with a magnetic field. Mathematically, these phenomena can be understood as the curl of the electric field (i.e., the current or spin) producing a (time varying) magnetic field or vise versa. Thus, one should also be able to induce a magnetic response in nano- and meso-scale materials by exploiting Maxwell-Faraday's law of induction through the design of the structure, by employing an electric field with instantaneous curl or do both to produce an instantaneous circulating (or displacement) current. Here we employ cylindrical vector beams with azimuthal polarization to create an angular (cylindrical) electric field, and selectively induce a magnetic response in metal nanoparticle-based nanomaterials at optical frequencies. This time-varying magnetic field at optical frequencies is induced in systems that do not possess spin or orbital angular momentum. Moreover, with the vector beam spectroscopy we also selectively drive electric dipole modes by excitation with a radially polarized light, and show that the strength of the electric and magnetic modes can be equal in magnitude in individual metal nano-structures. This work opens new opportunities for selective spectroscopic investigation of "dark modes" and Fano resonances in nanomaterials, metamaterials and control of nanomaterial excitations and dynamics.

  20. The Deposition of Electro-Optic Films on Semiconductors

    DTIC Science & Technology

    1994-09-26

    Optical Waveguides," I ~T. M . Graettinger, D. J. Lichtenwalner, A. F. Chow, 0. Auciello, and A. I. Kingon, ISIF 1994 Proceedings, submitted to Integrated3...Ferroelectrics. Appendix 2. "Growth of Epitaxial KNbO3 Thin Films," Thomas M . Graettinger,I P. A. Morris, A. Roshko, A. I. Kingon, 0. Auciello, D. J...34Epitaxial KNb03 Thin Films on KTa03, MgAI204, and MgO Substrates,ŗ A. F. Chow, D. J. Lichtenwalner, R. R. Woolcott, Jr., T. M . Gatigr 0. Auciello, and A. I

  1. Film Selection in a Cinematherapy Intervention with Preadolescents Experiencing Parental Divorce

    ERIC Educational Resources Information Center

    Marsick, Emily

    2010-01-01

    Film selection and children's reactions to films are discussed in this article based on a qualitative multiple-case study with three preadolescent-aged children experiencing parental divorce. Six films were selected based on recommended films in cinematherapy. Although many films have been recommended for cinematherapy, multiple participants'…

  2. Low earth orbit environmental effects on osmium and related optical thin-film coatings

    NASA Technical Reports Server (NTRS)

    Gull, T. R.; Herzig, H.; Osantowski, J. F.; Toft, A. R.

    1985-01-01

    A number of samples of optical thin film materials were flown on Shuttle flight STS-8 as part of an experiment to evaluate their interaction with residual atomic oxygen in low earth orbit. Osmium was selected because of its usefulness as a reflective optical coating for far-UV instruments and for confirmation of results from previous Shuttle flights in which such coatings disappeared. Reflectance data and photographic evidence are presented to support the hypothesis that the osmium disappearance is due to reaction with oxygen to form a volatile oxide. Platinum and iridium, which were included for comparison, fared much better.

  3. Poled polymer films for nonlinear optics

    SciTech Connect

    Singer, K.D.; Kuzyk, M.G.; Holland, W.R.; Cahill, P.A.

    1989-01-01

    Second harmonic generation was measured for a thin corona-poled film of a dicyanovinyl azo dye incorporated in the side-chain methacrylate polymer. Measurements were performed at a wavelength of 1.58 ..mu..m as a function of incident angle for both p- and s-polarized incident light. From these measurements the form and magnitude of the second harmonic coefficient tensor were determined. The molecular distribution implied by the data is consistent with a thermodynamic potential containing only the dipolar orienting energy acting during poling. We have also demonstrated anomalous-dispersion phase-matched second harmonic generation for the first time using electric field induced second harmonic generation (EFISH) in a liquid solution of Foron Brilliant Blue S-R (FBB). Results are described. 10 refs., 4 figs., 2 tabs.

  4. Optical constants and nonlinear calculations of fluorescein/FTO thin film optical system

    NASA Astrophysics Data System (ADS)

    Zahran, H. Y.; Iqbal, Javed; Yahia, I. S.

    2016-11-01

    The organic thin films of fluorescein dye were deposited on fluorine-doped tin oxide glass substrate by using low-cost spin coating technique. The surface of the deposited film was characterized by using AFM and X-ray diffraction spectroscopy, which shows that the film is uniform and amorphous. The spectrophotometric study was carried out at the wavelength range of 300-2500 nm. The spectral dependences of the linear refractive index and absorption index were found to decrease as the wavelength was increased. Tauc's plot study revealed that the film shows the direct transition and energy band gap values were found 1.75 eV and 3.55 eV for the thin film and the substrate, respectively. Optical constants were found nearly the same in the higher energy domain (1.0-4.5 eV). Spectroscopic method was employed to study the nonlinear optical susceptibility χ (3). The deposited thin film is a promising optical system for new generation of optoelectronics.

  5. Investigation of optical band gap and optical phonons in indium nitride and indium aluminum nitride films

    NASA Astrophysics Data System (ADS)

    Haddad, Daad Bourhan

    2003-07-01

    We have studied the optical band gap in InN thin films and the optical phonon modes in the ternary alloy thin films, In1-x AlxN (0 ≤ x ≤ 1). The In1-xAl xN films with 0 ≤ x ≤ 1 were grown by Plasma Source Molecular Beam Epitaxy (PSMBE) on sapphire (0001) substrates. The optical properties of InN thin films (˜0.5 mum thick) grown at different substrate temperatures have been measured in order to study the effect of electron degeneracy on the band gap measurement. Hall measurements indicate that the films are n-type with a high carrier concentration (>1020 cm -3). The optical absorption data on these samples show ne dependent band gap edge and a peak corresponding to plasmon due to strong electron degeneracy. By incorporating the influence of electron degeneracy on the optical absorption data, the calculated value of true band gap energy for these films is found to be ˜0.7 eV. This value is much smaller than the earlier reported values (˜1.9 eV) in the literature, but in better agreement with recent band gap measurements on high quality InN films. In addition, the analysis of the optical absorption data of a high quality non-degenerate InN film with ne ˜7 x 1017 cm-3, obtained from Cornell University, results in an observed optical band gap energy ˜0.6 eV. The role of plasmon and LO-phonon damping on the optical measurements of InN films is discussed. The phonon and plasmon damping dramatically modify the spectral features of the optical spectra and destabilize coupled-modes of the system. The phonon damping affects the optical properties in a qualitatively different way than plasmon damping. The low-energy optical transmission region formed in between the coupled-modes in weakly damped situations is investigated. The effect of plasmon and LO-phonon coupling on the analyses of the experimental infrared reflection data of InN films (with different electron densities) is discussed. UV and visible near-resonance enhanced Raman scattering measurements in

  6. Optical limiting effects in nanostructured silicon carbide thin films

    SciTech Connect

    Borshch, A A; Starkov, V N; Volkov, V I; Rudenko, V I; Boyarchuk, A Yu; Semenov, A V

    2013-12-31

    We present the results of experiments on the interaction of nanosecond laser radiation at 532 and 1064 nm with nanostructured silicon carbide thin films of different polytypes. We have found the effect of optical intensity limiting at both wavelengths. The intensity of optical limiting at λ = 532 nm (I{sub cl} ∼ 10{sup 6} W cm{sup -2}) is shown to be an order of magnitude less than that at λ = 1064 nm (I{sub cl} ∼ 10{sup 7} W cm{sup -2}). We discuss the nature of the nonlinearity, leading to the optical limiting effect. We have proposed a method for determining the amount of linear and two-photon absorption in material media. (nonlinear optical phenomena)

  7. Optical and Chemical Properties of Mixed-valent Rhenium Oxide Films Synthesized by Reactive DC Magnetron Sputtering

    DTIC Science & Technology

    2015-04-03

    and thus, were selected for detailed ex situ characterization. Chemical analysis via X - ray photoelectron spectroscopy confirmed that all films...Chemical analysis via X - ray photoelectron spectroscopy confirmed that all films consisted largely of ReO3, but had some con- tributions from Re2O3... X cm)1 [9,12] and minimal optical absorption are a direct consequence of the electronic configuration of ReO3, which contains a single free

  8. Structural and Optical Properties of Thick Freestanding AlN Films Prepared by Hydride Vapor Phase Epitaxy

    DTIC Science & Technology

    2012-01-01

    electronic device applications, optoe- lectronic devices are the driving force of AlN based material research. Deep ultraviolet laser diodes and light...films deposited on Si and SiC substrates, removed from the substrates by etching techniques, were used as seeds to grow AlN boules with a diameter...ranging from 0.5 to 1.75 in. Selected wafers were employed as substrates to deposit epitaxial AlN films with improved structural and optical properties

  9. Selective optical detection of aromatic vapors

    NASA Astrophysics Data System (ADS)

    Podgorsek, Robert P.; Franke, Hilmar

    2002-02-01

    A sensitive layer system of amorphous Teflon AF on silver has been coated on a glass substrate. With a monochromatic light source the reflectivity of the layer system as a function of the angle of incidence exhibits the surface-plasmon resonance as well as a set of leaky-mode resonances. These optical resonance phenomena are sensitive to small refractive-index changes that may be induced by diffusion of particles into the Teflon AF layer. On the basis of this effect, the aromatic vapors benzene; toluene; and o-, p-, and m-xylene have been investigated with different vapor concentrations. By selection of a distinct angle at a particular resonance, dynamic measurements can be performed. Assuming a diffusion process in accordance with Fick's law, the diffusion profile can be calculated as a function of time. As described by the Lorentz-Lorenz relation a refractive-index profile is induced that consequently interacts with the electromagnetic fields of the optical modes. With the function of the diffusion-induced refractive-index profile the shift of the resonance lines can be calculated from the measured reflectivity change as a function of time. The characteristic diffusion coefficients of the particular vapor allow for a distinction between the different types of aromate, even between the different xylenes.

  10. A polydopamine-modified optical fiber SPR biosensor using electroless-plated gold films for immunoassays.

    PubMed

    Shi, Se; Wang, Libing; Su, Rongxin; Liu, Boshi; Huang, Renliang; Qi, Wei; He, Zhimin

    2015-12-15

    A sensitive and stable electroless-plated gold film for the preparation of an optical fiber surface plasmon resonance (SPR) sensor is presented in this work, together with a facile antibody immobilization method. Gold nanoparticles were uniformly adsorbed onto the surface of an optical fiber forming a film with a thickness of approximately 56.3 nm. The sensor had a high sensitivity with 2054 nm/RIU and 3980 nm/RIU in the refractive index ranges of 1.333-1.359 and 1.359-1.386, respectively. An SPR biosensor was developed based on polydopamine-modified gold film (PDA-Au), which was fabricated by a simple and quick spontaneous polymerization of dopamine (DA) on the gold film. When goat anti-human IgG antibodies were immobilized, the PDA-Au surface had a larger resonant wavelength shift of 66.21 nm compared with the traditional 11-mercaptoundecanoic acid-modified gold film (MUA-Au) surface. In addition, the PDA-Au surface enabled the sensitive and selective determination of human IgG down to a concentration of 2 μg mL(-1) with a high sensitivity of 0.41 nm per μg mL(-1). The PDA-Au surface exhibited an approximately four fold higher sensitivity and an about seven fold lower LOD than the MUA-Au surface to human IgG. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Optical cavity-assisted broadband optical transparency of a plasmonic metal film

    NASA Astrophysics Data System (ADS)

    Liu, Zhengqi; Nie, Yiyou; Yuan, Wen; Liu, Xiaoshan; Huang, Shan; Chen, Jing; Gao, Huogui; Gu, Gang; Liu, Guiqiang

    2015-05-01

    We theoretically present a powerful method to achieve a continuous metal film structure with broadband optical transparency via introducing a dielectric Fabry-Pérot (FP) cavity. An incident optical field could be efficiently coupled and confined with the strong localized plasmons by the non-close-packed plasmonic crystal at the input part and could then become re-radiated output via the transmission channel supported by the dielectric cavity. The formed photonic-plasmonic system could therefore make the seamless metal film structure have a superior near-unity transparency (up to 97%) response and a broadband transparent spectrum with bandwidth >245 nm (with transmittance >90%) in the optical regime. The observed optical properties of the proposed structure can be highly tuned via varying the structural parameters. Based on the colloidal assembly method, the proposed plasmonic crystal can be fabricated in a large area. In addition, the achieved optical transparency can be retained in the extremely roughed metal film structure. Thereby, the findings could offer a feasible way to achieve a broadband transparent metal film structure and hold potential applications in transparent electrodes, touch screens and interactive electronics.

  12. Optical cavity-assisted broadband optical transparency of a plasmonic metal film.

    PubMed

    Liu, Zhengqi; Nie, Yiyou; Yuan, Wen; Liu, Xiaoshan; Huang, Shan; Chen, Jing; Gao, Huogui; Gu, Gang; Liu, Guiqiang

    2015-05-08

    We theoretically present a powerful method to achieve a continuous metal film structure with broadband optical transparency via introducing a dielectric Fabry-Pérot (FP) cavity. An incident optical field could be efficiently coupled and confined with the strong localized plasmons by the non-close-packed plasmonic crystal at the input part and could then become re-radiated output via the transmission channel supported by the dielectric cavity. The formed photonic-plasmonic system could therefore make the seamless metal film structure have a superior near-unity transparency (up to 97%) response and a broadband transparent spectrum with bandwidth >245 nm (with transmittance >90%) in the optical regime. The observed optical properties of the proposed structure can be highly tuned via varying the structural parameters. Based on the colloidal assembly method, the proposed plasmonic crystal can be fabricated in a large area. In addition, the achieved optical transparency can be retained in the extremely roughed metal film structure. Thereby, the findings could offer a feasible way to achieve a broadband transparent metal film structure and hold potential applications in transparent electrodes, touch screens and interactive electronics.

  13. Optical properties of vanadium dioxide thin film in nanoparticle structure

    NASA Astrophysics Data System (ADS)

    Fang, Baoying; Li, Yi; Tong, Guoxiang; Wang, Xiaohua; Yan, Meng; Liang, Qian; Wang, Feng; Qin, Yuan; Ding, Jie; Chen, Shaojuan; Chen, Jiankun; Zheng, Hongzhu; Yuan, Wenrui

    2015-09-01

    The thermo-optic effect and infrared optical properties of VO2 nanoparticles were studied to obtain an optical material with special property that can be used in smart windows. The reflectance and transmittance spectra of the VO2 nanoparticles with different duty cycles at different temperatures were simulated with a specific dispersion relation. Vanadium metal nanoparticles were deposited on glass substrate by magnetic reactive sputtering with porous alumina template (AAO) mask, and the VO2 nanoparticles were prepared by thermal oxidation. The nanostructure and optical properties of the VO2 nanoparticles were characterized by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and spectrophotometry. The method of preparation of the sample is economical and the phase transition temperature is observed to drop to 43 °C. The transmission at 1700 nm exhibits a variation of 29% between the metallic and semiconducting states. The VO2 nanoparticles exhibit a significant thermochromic property. The transmittance of the VO2 nanoparticles is improved compared with the VO2 film. The decrease in phase transition temperature and the enhancement of optical properties demonstrate that VO2 film in nanoparticle structure is a viable candidate material for smart windows.

  14. Optical Fiber Relative-Humidity Sensor with Polyvinyl Alcohol Film

    NASA Astrophysics Data System (ADS)

    Gastón, Ainhoa; Pérez, Fátima; Sevilla, Joaquín

    2004-07-01

    We describe a fiber-optic relative-humidity (RH) sensor comprising a moisture-sensitive overlay on a single-mode side-polished fiber. The hygroscopic polymeric material deposited was polyvinyl alcohol (PVA), which proved to have good adherence and stability. The film reached a fast equilibrium with atmospheric moisture (in less than 1 min), inducing changes in the output optical power of ~10 dB for the 70%-90% RH range. To yield a low-cost device, single-mode standard communication fibers were used; therefore all the components of the sensor can be commercial, mass-produced telecommunication devices. The experimental results obtained are consistent with the expected behavior of the system; the output power decreases because of losses in the polished region of the fiber as the refractive index of its external medium approaches the fiber core value. Because the external medium is PVA film, its refractive index changes in response to its water content.

  15. Nonlinear optical properties of calcium barium niobate epitaxial thin films.

    PubMed

    Bancelin, Stéphane; Vigne, Sébastien; Hossain, Nadir; Chaker, Mohammed; Légaré, François

    2016-07-25

    We investigate the potential of epitaxial calcium barium niobate (CBN) thin film grown by pulsed laser deposition for optical frequency conversion. Using second harmonic generation (SHG), we analyze the polarization response of the generated signal to determine the ratios d15 / d32 and d33 / d32 of the three independent components of the second-order nonlinear susceptibility tensor in CBN thin film. In addition, a detailed comparison to the signal intensity obtained in a y-cut quartz allows us to measure the absolute value of these components in CBN thin film: d15 = 5 ± 2 pm / V, d32 = 3.1 ± 0.6 pm / V and d33 = 9 ± 2 pm / V.

  16. Thin Film Metal Coated Fiber Optic Hydrophone Probe

    PubMed Central

    Gopinath, R.; Arora, P.; Gandhi, G.; Daryoush, A.S.; El-Sherif, M.; Lewin, P.A.

    2010-01-01

    The purpose of this work was to improve on sensitivity performance of fiber sensor employed as Fiber Optic Hydrophone Probe (FOHP) by nano-scale thin film gold coating. The fiber is designed to provide a uniform and spatial averaging free response up to 100 MHz by etching down to an active diameter of about 9 μm. The sensitivity performance of straight cleaved (i.e. full size core and cladding) uncoated, tapered uncoated and tapered thin film gold coated fiber sensors were compared in the frequency range of 1.5 MHz to 20 MHz in the presence of acoustic pressure amplitude levels of up to 6 MPa. An unprecedented voltage sensitivity of −245 dB re 1V/uPa (560 mV/ MPa) was measured for thin film gold coated FOHP by optimizing the gold coating thickness. PMID:19881652

  17. Maximum statistical increase of optical absorption in textured semiconductor films

    NASA Astrophysics Data System (ADS)

    Deckman, H. W.; Roxlo, C. B.; Yablonovitch, E.

    1983-09-01

    It is noted that the complete statistical randomization of the direction of propagation of light trapped in semiconductor films can result in a large absorption enhancement. The absorption of a-SiH(x) films textured by the natural lithography process was evaluated using a calorimetric technique, photothermal deflection spectroscopy. It is shown that textures with feature sizes roughly equal to a wavelength of light can be fabricated which completely internally randomize incident light. Absorption enhancement factors up to 11.5 were obtained in experimental studies, which are in agreement with the predictions of statistical ray optics. It is concluded that these findings will be useful for the optimization of solar cells and other devices for which high levels of absorption are desired in thin films.

  18. Thin film metal coated fiber optic hydrophone probe.

    PubMed

    Gopinath Minasamudram, Rupa; Arora, Piyush; Gandhi, Gaurav; Daryoush, Afshin S; El-Sherif, Mahmoud A; Lewin, Peter A

    2009-11-01

    Our purpose is to improve the performance sensitivity of a fiber sensor used as a fiber optic hydrophone probe (FOHP) by the addition of nanoscale thin film gold coating. The fiber is designed to provide a uniform and spatial averaging free response up to 100 MHz by etching down to an active diameter of approximately 9 mum. The performance sensitivity of straight cleaved (i.e., full size core and cladding) uncoated, tapered uncoated, and tapered thin film gold-coated fiber sensors was compared in the frequency range from 1.5 to 20 MHz in the presence of acoustic amplitude pressure levels as high as 6 MPa. An unprecedented voltage sensitivity of -245 dB relative to 1 V/muPa (560 mV/MPa) was measured for a thin film gold-coated FOHP by optimizing the gold coating thickness.

  19. Ray optics behavior of flux avalanche propagation in superconducting films

    NASA Astrophysics Data System (ADS)

    Mikheenko, P.; Johansen, T. H.; Chaudhuri, S.; Maasilta, I. J.; Galperin, Y. M.

    2015-02-01

    Experimental evidence of wave properties of dendritic flux avalanches in superconducting films is reported. Using magneto-optical imaging the propagation of dendrites across boundaries between a bare NbN film and areas coated by a Cu layer was visualized, and it was found that the propagation is refracted in full quantitative agreement with Snell's law. For the studied film of 170 nm thickness and a 0.9 μ m thick metal layer, the refractive index was close to n =1.4 . The origin of the refraction is believed to be caused by the dendrites propagating as an electromagnetic shock wave, similar to damped modes considered previously for normal metals. The analogy is justified by the large dissipation during the avalanches raising the local temperature significantly. Additional time-resolved measurements of voltage pulses generated by segments of the dendrites traversing an electrode confirm the consistency of the adopted physical picture.

  20. Optical properties of thin films of CdSe obtained by spray pyrolisis

    NASA Astrophysics Data System (ADS)

    Gonzalez, A. M. P.; Tepantlan, C. S.; Carrillo, F. R.

    2006-06-01

    In this paper the optical properties of CdSe thin films obtained by spray pyrolisis are presented. The films are prepared by Sodium Selenosulphate (Na2SSeO3) and Cadmium Chloride (CdC12) mixing in aqueous environment. Optical parameters of the films (refractive index, absorption coefficient and optical bangap) were calculated from transmittance spectra. The obtained values of the optical bangap are compared with the result obtained by other deposition methods.

  1. Measurement of Nonlinear Optical Properties of Single-Crystal Thin-Films of 3-Methyl-4-Methoxy-4'-Nitrostilbene (MMONS)

    NASA Astrophysics Data System (ADS)

    Tan, Shida; Bhowmik, Achintya; Thakur, Mrinal

    2000-03-01

    Excellent optical quality large area ( ~1 cm^2) single-crystal thin-films of MMONS were prepared by modified shear method.(M. Thakur and S. Meyler, Macromolecules 18, 2341 (1985); M. Thakur, Y. Shani, G. C. Chi, and K. O'Brien, Synth. Met. 28, D595 (1989).) This material belongs to mm2 point group.(D. Bierlein, L. K. Cheng, Y. Wang, and W. Tam, Appl. Phys. Lett. 56, 423 (1990).) Polarized optical microscopic and X-ray diffraction studies were performed to characterize the single-crystal films. The surface orientation of the films was (100). Polarized optical absorption measurements showed a large dichroism in the film as the molecules are oriented almost parallel to the film-plane. Using a mode-locked Nd:YAG laser ( ~100 ps, 82 MHz), the significant d-coefficients were determined by polarization selective SHG measurements, and the electro-optic coefficients were determined by field-induced birefringence measurements. The measured magnitudes of d- and r-coefficients are d_33=198±10 pm/V, d_32=78±5 pm/V, r_33=52±5 pm/V, and r_23=21±2 pm/V at 1064 nm. The results indicate that these films are promising for applications in guided-wave SHG and electro-optics.

  2. Nonlinear Optical Properties of Organic and Polymeric Thin Film Materials of Potential for Microgravity Processing Studies

    NASA Technical Reports Server (NTRS)

    Abdeldayem, Hossin; Frazier, Donald O.; Paley, Mark S.; Penn, Benjamin; Witherow, William K.; Bank, Curtis; Shields, Angela; Hicks, Rosline; Ashley, Paul R.

    1996-01-01

    In this paper, we will take a closer look at the state of the art of polydiacetylene, and metal-free phthalocyanine films, in view of the microgravity impact on their optical properties, their nonlinear optical properties and their potential advantages for integrated optics. These materials have many attractive features with regard to their use in integrated optical circuits and optical switching. Thin films of these materials processed in microgravity environment show enhanced optical quality and better molecular alignment than those processed in unit gravity. Our studies of these materials indicate that microgravity can play a major role in integrated optics technology. Polydiacetylene films are produced by UV irradiation of monomer solution through an optical window. This novel technique of forming polydiacetylene thin films has been modified for constructing sophisticated micro-structure integrated optical patterns using a pre-programmed UV-Laser beam. Wave guiding through these thin films by the prism coupler technique has been demonstrated. The third order nonlinear parameters of these films have been evaluated. Metal-free phthalocyanine films of good optical quality are processed in our laboratories by vapor deposition technique. Initial studies on these films indicate that they have excellent chemical, laser, and environmental stability. They have large nonlinear optical parameters and show intrinsic optical bistability. This bistability is essential for optical logic gates and optical switching applications. Waveguiding and device making investigations of these materials are underway.

  3. Gold nanoparticles reinforced poly (vinyl alcohol) of self-standing optical films.

    PubMed

    Ram, S; Tripathy, P; Fecht, H J

    2007-09-01

    A simple one-step process is developed to synthesize self-standing optical films of Au-doped polymer of poly(vinyl alcohol) (PVA). The visible color could be tuned precisely over a wide range from the violet to a yellowish with selective Au-contents from 0.1 to 5.0 wt%. The synthetic procedure involves a caloric Au3+ --> Au reaction in aqueous PVA at 60-90 degrees C temperatures followed by casting the sample (Au-nanocrystals (NCs) embedding in the PVA polymer molecules) as films or other shapes. Stable color persists of nanocolloids as well as films. The NCs are thin platelets of triangular, square, rectangular, or hexagonal shapes. There are very few pentagonal platelets and nanorods. As analyzed with microstructure, the NCs formation results in a structural anisotropy by the preferential adsorption of PVA on selective facets. An Au-content dependent emission occurs in the 400-650 nm regions, useful for possible optical data storage, nonlinear optical devices, and color pigments.

  4. Investigation of local and nonlocal nonlinear optical refraction effect in IZO thin films

    NASA Astrophysics Data System (ADS)

    Htwe, Zin Maung; Zhang, Yun-Dong; Yao, Cheng-Bao; Li, Hui; Yuan, Ping

    2016-10-01

    We report the local and nonlocal nonlinear optical refraction properties of indium doped zinc oxide (IZO) thin films using closed aperture Z-scan technique. The Z-scan results show the films have positive nonlinear optical refraction properties. The nonlocal parameter m of samples is increased with indium. In both of local and nonlocal studies, the nonlinear optical refractions of thin films were increased with In contents and laser energy. This relation reveals the role of In composition in IZO affects on the nonlinear optical responses of the films. These results make the IZO thin films as the promising application in optoelectronics devices.

  5. Systems Issues Pertaining to Holographic Optical Data Storage in Thick Bacteriorhodopsin Films

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Timucin, Dogan A.; Gary, Charles K.; Oezcan, Meric; Smithey, Daniel T.; Crew, Marshall; Lau, Sonie (Technical Monitor)

    1998-01-01

    The optical data storage capacity and raw bit-error-rate achievable with thick photochromic bacteriorhodopsin (BR) films are investigated for sequential recording and read- out of angularly- and shift-multiplexed digital holograms inside a thick blue-membrane D85N BR film. We address the determination of an exposure schedule that produces equal diffraction efficiencies among each of the multiplexed holograms. This exposure schedule is determined by numerical simulations of the holographic recording process within the BR material, and maximizes the total grating strength. We also experimentally measure the shift selectivity and compare the results to theoretical predictions. Finally, we evaluate the bit-error-rate of a single hologram, and of multiple holograms stored within the film.

  6. Systems Issues Pertaining to Holographic Optical Data Storage in Thick Bacteriorhodopsin Films

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Timucin, Dogan A.; Gary, Charles K.; Oezcan, Meric; Smithey, Daniel T.; Crew, Marshall; Lau, Sonie (Technical Monitor)

    1998-01-01

    The optical data storage capacity and raw bit-error-rate achievable with thick photochromic bacteriorhodopsin (BR) films are investigated for sequential recording and read- out of angularly- and shift-multiplexed digital holograms inside a thick blue-membrane D85N BR film. We address the determination of an exposure schedule that produces equal diffraction efficiencies among each of the multiplexed holograms. This exposure schedule is determined by numerical simulations of the holographic recording process within the BR material, and maximizes the total grating strength. We also experimentally measure the shift selectivity and compare the results to theoretical predictions. Finally, we evaluate the bit-error-rate of a single hologram, and of multiple holograms stored within the film.

  7. Synthesis, growth kinetics and optical properties of zinc oxide nanoparticle suspensions and thin films

    NASA Astrophysics Data System (ADS)

    Wong, Eva May

    2000-10-01

    Colloidal chemistry techniques were used to synthesize ZnO particles in the nanometer size regime. The particle aging kinetics were determined by monitoring the optical band edge absorption and using the effective mass model to approximate the particle size as a function of time. The growth kinetics of the ZnO particles were found to follow the Lifshitz, Slyozov, Wagner theory for Ostwald ripening. In this model, the higher curvature and hence chemical potential of smaller particles provides a driving force for dissolution. The larger particles continue to grow by diffusion limited transport of species dissolved in solution. Thin films of ZnO quantum particles were fabricated by electrophoretic deposition from suspensions prepared via a colloidal chemistry synthesis route. Films were prepared at constant current thus eliminating the limited deposition rate associated with constant voltage deposition. The kinetics for the deposition of thin films were determined using optical absorbance techniques in conjunction with atomic absorption spectrometry. The particle velocity during deposition and the charge on the particles were determined from the deposition kinetics. The thin films prepared by electrophoretic deposition exhibited optical properties characteristic of the quantum size particles. The average particle size, and hence the optical properties, were tailored by controlling the aging time and temperature of the suspensions. Both the band-to-band and visible photoluminescence were progressively blue shifted, relative to the bulk value, with decreasing particle size in the film. A linear dependence was found between the band-to-band and visible emission. Finally, particle growth was manipulated by the specific adsorption of a series of capping ligands at the particle surface. The adsorption of the capping ligands was found to produce a diffusion barrier such that particle growth was stunted following incorporation with the extent of this effect being dependent

  8. Bioinspired Superhydrophobic Highly Transmissive Films for Optical Applications.

    PubMed

    Vüllers, Felix; Gomard, Guillaume; Preinfalk, Jan B; Klampaftis, Efthymios; Worgull, Matthias; Richards, Bryce; Hölscher, Hendrik; Kavalenka, Maryna N

    2016-11-01

    Inspired by the transparent hair layer on water plants Salvinia and Pistia, superhydrophobic flexible thin films, applicable as transparent coatings for optoelectronic devices, are introduced. Thin polymeric nanofur films are fabricated using a highly scalable hot pulling technique, in which heated sandblasted steel plates are used to create a dense layer of nano- and microhairs surrounding microcavities on a polymer surface. The superhydrophobic nanofur surface exhibits water contact angles of 166 ± 6°, sliding angles below 6°, and is self-cleaning against various contaminants. Additionally, subjecting thin nanofur to argon plasma reverses its surface wettability to hydrophilic and underwater superoleophobic. Thin nanofur films are transparent and demonstrate reflection values of less than 4% for wavelengths ranging from 300 to 800 nm when attached to a polymer substrate. Moreover, used as translucent self-standing film, the nanofur exhibits transmission values above 85% and high forward scattering. The potential of thin nanofur films for extracting substrate modes from organic light emitting diodes is tested and a relative increase of the luminous efficacy of above 10% is observed. Finally, thin nanofur is optically coupled to a multicrystalline silicon solar cell, resulting in a relative gain of 5.8% in photogenerated current compared to a bare photovoltaic device. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Structural and optical studies of Au doped titanium oxide films

    NASA Astrophysics Data System (ADS)

    Alves, E.; Franco, N.; Barradas, N. P.; Nunes, B.; Lopes, J.; Cavaleiro, A.; Torrell, M.; Cunha, L.; Vaz, F.

    2012-02-01

    Thin films of TiO 2 were doped with Au by ion implantation and in situ during the deposition. The films were grown by reactive magnetron sputtering and deposited in silicon and glass substrates at a temperature around 150 °C. The undoped films were implanted with Au fluences in the range of 5 × 10 15 Au/cm 2-1 × 10 17 Au/cm 2 with a energy of 150 keV. At a fluence of 5 × 10 16 Au/cm 2 the formation of Au nanoclusters in the films is observed during the implantation at room temperature. The clustering process starts to occur during the implantation where XRD estimates the presence of 3-5 nm precipitates. After annealing in a reducing atmosphere, the small precipitates coalesce into larger ones following an Ostwald ripening mechanism. In situ XRD studies reveal that Au atoms start to coalesce at 350 °C, reaching the precipitates dimensions larger than 40 nm at 600 °C. Annealing above 700 °C promotes drastic changes in the Au profile of in situ doped films with the formation of two Au rich regions at the interface and surface respectively. The optical properties reveal the presence of a broad band centered at 550 nm related to the plasmon resonance of gold particles visible in AFM maps.

  10. Reflective optical bi-stability of antiferromagnetic films

    NASA Astrophysics Data System (ADS)

    Bai, J.; Fu, S. F.; Zhou, S.; Wang, X. Z.

    2011-10-01

    We investigate one magnetically nonlinear response of antiferromagnetic (AF) films to incident electromagnetic waves, or the reflective optical bi-stability (ROB). Such geometry is used, where the AF anisotropy axis and external static magnetic field both are parallel to the film surfaces and normal to the incident plane. For TE incident waves with the electric component transverse to the incident plane, the ROB of the AF film with the absorption is calculated, but the case of TM incident waves is neglected since no magnetic nonlinearity is induced in this geometry. The bi-stability is completely different in the two resonant-frequency vicinities. Two kinds of bi-stability are found in the higher vicinity, and their features versus incident power are opposite. We also find that there are critical incident angle and critical film thickness for the existence of bi-stability. The bi-stability disappears when the film thickness or incident angle exceeds its critical value. Because the properties of bi-stable reflection sensitively depend on the external field and the incident angle, this bi-stability can be easily modulated by means of changing these quantities.

  11. Vitrified chiral-nematic liquid crystalline films for selective reflection and circular polarization

    SciTech Connect

    Katsis, D.; Chen, P.H.M.; Mastrangelo, J.C.; Chen, S.H.; Blanton, T.N.

    1999-06-01

    Nematic and left-handed chiral-nematic liquid crystals comprising methoxybiphenylbenzoate and (S)-(-)-1-phenylethylamine pendants to a cyclohexane core were synthesized and characterized. Although pristine samples were found to be polycrystalline, thermal quenching following heating to and annealing at elevated temperatures permitted the molecular orders characteristic of liquid crystalline mesomorphism to be frozen in the glassy state. Left at room temperature for 6 months, the vitrified liquid crystalline films showed no evidence of recrystallization. An orientational order parameter of 0.65 was determined with linear dichroism of a vitrified nematic film doped with Exalite 428 at a mole fraction of 0.0025. Birefringence dispersion of a blank vitrified nematic film was determined using a phase-difference method complemented by Abbe refractometry. A series of vitrified chiral-nematic films were prepared to demonstrate selective reflection and circular polarization with a spectral region tunable from blue to the infrared region by varying the chemical composition. The experimentally measured circular polarization spectra were found to agree with the Good-Karali theory in which all four system parameters were determined a priori: optical birefringence, average refractive index, selective reflection wavelength, and film thickness.

  12. Optical properties of metal-hydride switchable films

    NASA Astrophysics Data System (ADS)

    Griessen, Ronald

    2001-03-01

    In 1996 we discovered that yttrium-, lanthanum-, and rare-earth-hydride (REHx) films [1] protected by a thin palladium layer, exhibit spectacular changes in their optical properties when the hydrogen concentration x is increased from 2 to 3. For example, a 500 nm thick YH2 film is metallic and shiny while YH3 is yellowish and transparent. The transition is reversible, fast [2, 3], and can simply be induced by adding or removing hydrogen from the gas phase, an electrolyte or from an H containing liquid. The optical switching that occurs near the metal-insulator transition of these hydrides is remarkably robust as it is not affected by structural or compositional disorder. It occurs in polycrystalline and epitaxial films, in alloys with cubic or hexagonal crystal structures,and deuterides [4] switch as well as hydrides. At small length scales epitaxial YHx films exhibit surprising structural properties which open the way to pixel-by-pixel optical switching [5]. Colour-neutral switchable mirrors based on RE-Mg alloys [6] can be used in all-solid-state switchable devices. Newest results for Rare-Earth free switchable mirrors will be presented. [1] J. N. Huiberts, R. Griessen, J. H. Rector, R. J. Wijngaarden, J. P. Dekker, D. G. de Groot and N. J. Koeman, Nature 380 (1996) 231; [2] S. J. van der Molen, J. W. J. Kerssemakers, J. H. Rector, N. J. Koeman, B. Dam, R. Griessen, J. Appl. Phys. 86 (1999) 6107; [3] F. J. A. den Broeder, S. J. van der Molen, et al., Nature 394 (1998)656; [4] A. T. M. van Gogh, E. S. Kooij, R. Griessen, Phys. Rev. Lett. 83 (1999) 4614; [5] J. W. J. Kerssemakers, S. J. van der Molen and R. Griessen, Nature 406 (2000) 489; [6] P. van der Sluis, M. Ouwerkerk and P. A. Duine, Appl. Phys. Lett. 70 (1997) 3356.

  13. Electrical, Electrochemical, and Optical Characterization of Ceria Films

    NASA Astrophysics Data System (ADS)

    Oh, Tae-Sik

    Acceptor-doped ceria has been recognized as a promising intermediate temperature solid oxide fuel cell electrode/electrolyte material. For practical implementation of ceria as a fuel cell electrolyte and for designing model experiments for electrochemical activity, it is necessary to fabricate thin films of ceria. Here, metal-organic chemical vapor deposition was carried out in a homemade reactor to grow ceria films for further electrical, electrochemical, and optical characterization. Doped/undoped ceria films are grown on single crystalline oxide wafers with/without Pt line pattern or Pt solid layer. Deposition conditions were varied to see the effect on the resultant film property. Recently, proton conduction in nanograined polycrystalline pellets of ceria drew much interest. Thickness-mode (through-plane, z-direction) electrical measurements were made to confirm the existence of proton conductivity and investigate the nature of the conduction pathway: exposed grain surfaces and parallel grain boundaries. Columnar structure presumably favors proton conduction, and we have found measurable proton conductivity enhancement. Electrochemical property of gas-columnar ceria interface on the hydrogen electrooxidation is studied by AC impedance spectroscopy. Isothermal gas composition dependence of the electrode resistance was studied to elucidate Sm doping level effect and microstructure effect. Significantly, preferred orientation is shown to affect the gas dependence and performance of the fuel cell anode. A hypothesis is proposed to explain the origin of this behavior. Lastly, an optical transmittance based methodology was developed to obtain reference refractive index and microstructural parameters (thickness, roughness, porosity) of ceria films via subsequent fitting procedure.

  14. Selecting films for sex research: gender differences in erotic film preference.

    PubMed

    Janssen, Erick; Carpenter, Deanna; Graham, Cynthia A

    2003-06-01

    The aim of this study was to explore gender differences in sexual responsiveness to erotic films that had been selected for their differential appeal for men and women. A secondary objective was to identify variables that influence sexual arousal and explore whether these variables differ for men and women. Fifteen men (M age = 26 yrs) and 17 women (M age = 24 yrs) were presented with 20 film clips depicting heterosexual interactions, half of which were female- and the other half male-selected, and were asked to rate the clips on a number of dimensions. Overall, men found the film clips more sexually arousing than did the women. Gender differences in arousal were negligible for female-selected clips but substantial for male-selected clips. Furthermore, men and women experienced higher levels of sexual arousal to clips selected for individuals of their own gender. Cluster regression analyses, explaining 77% of the variance for male and 65% for female participants, revealed that men's sexual arousal was dependent upon the attractiveness of the female actor, feeling interested, and both "imagining oneself as a participant" and "watching as an observer." For women, with all variables entered, only "imagining oneself as a participant" contributed to sexual arousal ratings. The findings suggest that how films are selected in sex research is an important variable in predicting levels of sexual arousal reported by men and women.

  15. Preparation of flexible optical waveguide film with refractive index tunability

    NASA Astrophysics Data System (ADS)

    Kwon, Yong Ku; Noh, Seung Ju; Han, Jin Young; Suk, Min Kyun; Heo, Sung Ik; Jin, Sun Jin; Ahn, Hang Hee; Ahn, Cheol Hee

    2012-09-01

    Novel organic-inorganic hybrid materials were successfully synthesized by non-hydrolytic sol-gel processing. Crack-free and thick films were produced with no remaining traces of solvents without high volume shrinkage. Adjusting the chemical composition of the materials allows the precise tailoring of the optical properties of the materials, such as optical loss, birefringence, refractive index, and thermo-optic coefficient. They can be fabricated into the step index optical waveguide structures with well-defined and reproducible refractive index differences within 0.001. The transmission performance of each waveguide channel was tested using a 10 Gbps data stream. The electrical output signal from a photodetector, connected to a wide-band oscilloscope, displays a clear 10 Gbps eye pattern. We produced a series of flexible optical waveguides from organic-inorganic hybrid materials by using soft-lithographic technique. The optical losses of the flexible waveguide arrays bent over various curvatures were measured and the transmission performance of each waveguide channel was also tested. The bending losses of a flexible waveguide array were measured and found to yield no significant loss above 2 mm diameter curvature.

  16. Area selective molecular layer deposition of polyurea films.

    PubMed

    Prasittichai, Chaiya; Zhou, Han; Bent, Stacey F

    2013-12-26

    Patterned organic thin films with submicrometer features are of great importance in applications such as nanoelectronics and optoelectronics. We present here a new approach for creating patterned organic films using area selective molecular layer deposition (MLD). MLD is a technique that allows for conformal deposition of nanoscale organic thin films with exceptional control over vertical thickness and composition. By expanding the technique to allow for area selective MLD, lateral patterning of the film can be achieved. In this work, polyurea thin films were deposited by alternating pulses of 1,4-phenylenediisocyanate (PDIC) and ethylenediamine (ED) in a layer-by-layer fashion with a linear growth rate of 5.3 Å/cycle. Studies were carried out to determine whether self-assembled monolayer (SAM) formed from octadecyltrichlorosilane (ODTS) could block MLD on silicon substrates. Results show that the MLD process is impeded by the SAM. To test lateral patterning in MLD, SAMs were patterned onto silicon substrates using two different approaches. In one approach, SiO2-coated Si(100) substrates were patterned with an ODTS SAM by soft lithography in a well-controlled environment. In the second approach, patterned ODTS SAM was formed on H-Si/SiO2 patterned wafers by employing the chemically selective adsorption of ODTS on SiO2 over H-Si. Auger electron spectroscopy results revealed that the polyurea film is deposited predominantly on the ODTS-free regions of both patterned substrates, indicating sufficient blocking of MLD by the ODTS SAM layer to replicate the pattern. The method we describe here offers a novel approach for fabricating high quality, three-dimensional organic structures.

  17. Optical filters for wavelength selection in fluorescence instrumentation.

    PubMed

    Erdogan, Turan

    2011-04-01

    Fluorescence imaging and analysis techniques have become ubiquitous in life science research, and they are poised to play an equally vital role in in vitro diagnostics (IVD) in the future. Optical filters are crucial for nearly all fluorescence microscopes and instruments, not only to provide the obvious function of spectral control, but also to ensure the highest possible detection sensitivity and imaging resolution. Filters make it possible for the sample to "see" light within only the absorption band, and the detector to "see" light within only the emission band. Without filters, the detector would not be able to distinguish the desired fluorescence from scattered excitation light and autofluorescence from the sample, substrate, and other optics in the system. Today the vast majority of fluorescence instruments, including the widely popular fluorescence microscope, use thin-film interference filters to control the spectra of the excitation and emission light. Hence, this unit emphasizes thin-film filters. After briefly introducing different types of thin-film filters and how they are made, the unit describes in detail different optical filter configurations in fluorescence instruments, including both single-color and multicolor imaging systems. Several key properties of thin-film filters, which can significantly affect optical system performance, are then described. In the final section, tunable optical filters are also addressed in a relative comparison.

  18. The Optical Properties of Hydrogenated Amorphous Carbon Films

    NASA Astrophysics Data System (ADS)

    Furton, D. G.; Witt, A. N.

    1993-01-01

    We present the initial results of a laboratory study of hydrogenated amorphous carbon (HAC) thin films. We produce a quantitative summary of the optical and physical properties of a consistent set of HAC films processed in various ways and use these results to gain insight into the formation and evolution of dust grains in the interstellar medium. HAC thin films were deposited on NaCl coated substrates in a plasma-enhanced chemical-vapor deposition (PECVD) chamber, removed from the substrates, and characterized and processed in a variety of ways. Raman, photoluminescence (PL), transmission, and absorption spectroscopy were used to characterize these films in the visible. Infrared absorption and PL spectroscopy were used to analyze these films in the 1-20 micron region. Electron energy-loss spectroscopy (EELS) was used to calculate the index of refraction in the UV and the sp(2}/sp({3)) bonding ratio, and combustion analysis was used to determine the C/H ratio. Each member of a set of identically grown films was characterized as described above, processed to various extents, then characterized again. Some of the films were thermally annealed in vacuum over a range of temperatures and durations, while others were exposed to intense UV radiation. Our initial results are summarized as follows: The H-concentration, PL efficiency, band-gap, and transmission in the visible decrease with the extent of thermal or UV annealing. Thermally induced changes occur rapidly and long-term annealing at lower temperatures does not produce the same effects as higher temperature annealing. The films are essentially graphitized when annealed at temperatures higher than about 400(deg) C and they are completely obliterated when exposed to very intense UV radiation. We have also developed a thermal effusion oven to test to what extent HAC films can be ``rehydrogenated'' by exposure to neutral atomic hydrogen. These experiments are nearly complete and the results will be included if possible

  19. Enhanced optical discrimination system based on switchable retroreflective films

    NASA Astrophysics Data System (ADS)

    Schultz, Phillip; Heikenfeld, Jason

    2016-04-01

    Reported herein is the design, characterization, and demonstration of a laser interrogation and response optical discrimination system based on large-area corner-cube retroreflective films. The switchable retroreflective films use light-scattering liquid crystal to modulate retroreflected intensity. The system can operate with multiple wavelengths (visible to infrared) and includes variable divergence optics for irradiance adjustments and ease of system alignment. The electronic receiver and switchable retroreflector offer low-power operation (<4 mW standby) on coin cell batteries with rapid interrogation to retroreflected signal reception response times (<15 ms). The entire switchable retroreflector film is <1 mm thick and is flexible for optimal placement and increased angular response. The system was demonstrated in high ambient lighting conditions (daylight, 18k lux) with a visible 10-mW output 635-nm source out to a distance of 400 m (naked eye detection). Nighttime demonstrations were performed using a 1.5-mW, 850-nm infrared laser diode out to a distance of 400 m using a night vision camera. This system could have tagging and conspicuity applications in commercial or military settings.

  20. Optical characterization of contaminant film. [long duration exposure facility

    NASA Technical Reports Server (NTRS)

    Blakkolb, Brian K.; Yaung, James Y.; Kosic, Tom; Bowen, Howard

    1992-01-01

    The so called 'nicotine stain' documented at many locations on the Long Duration Exposure Facility is still unexplained as to the exact origin and mechanism of deposition, although enough is known to have some understanding of the conditions coincident for the formation of the deposits. Direct and scattered atomic oxygen flux, and solar ultraviolet radiation interacting with materials outgassing products have all been implicated in the formation of the dark brown contamination deposits. The nicotine stain represents a potential of performance degradation for spacecraft designed for long term operation in low Earth orbit and therefore, a need exists to characterize this form of spacecraft self contamination and quantify the impact on thermal/optical systems. Optical property measurements in the spectral range of 2 to 10 microns were performed on specimens of the contaminated film. Reflectance measurements of the contaminant film as deposited on the surface and as free standing films are presented along with transmission spectra for the bulk material. Thickness measurements along with micrographic examination of the cross section of the deposit reveal the layered structure of the deposit which further implicates solar illumination as a factor in the deposition mechanism.

  1. Optical characterization of contaminant film. [long duration exposure facility

    NASA Technical Reports Server (NTRS)

    Blakkolb, Brian K.; Yaung, James Y.; Kosic, Tom; Bowen, Howard

    1992-01-01

    The so called 'nicotine stain' documented at many locations on the Long Duration Exposure Facility is still unexplained as to the exact origin and mechanism of deposition, although enough is known to have some understanding of the conditions coincident for the formation of the deposits. Direct and scattered atomic oxygen flux, and solar ultraviolet radiation interacting with materials outgassing products have all been implicated in the formation of the dark brown contamination deposits. The nicotine stain represents a potential of performance degradation for spacecraft designed for long term operation in low Earth orbit and therefore, a need exists to characterize this form of spacecraft self contamination and quantify the impact on thermal/optical systems. Optical property measurements in the spectral range of 2 to 10 microns were performed on specimens of the contaminated film. Reflectance measurements of the contaminant film as deposited on the surface and as free standing films are presented along with transmission spectra for the bulk material. Thickness measurements along with micrographic examination of the cross section of the deposit reveal the layered structure of the deposit which further implicates solar illumination as a factor in the deposition mechanism.

  2. Optical characterization of hydrogenated silicon thin films using interference technique

    NASA Astrophysics Data System (ADS)

    Globus, Tatiana; Ganguly, Gautam; Roca i Cabarrocas, Pere

    2000-08-01

    This work introduces an application of an "interference spectroscopy technique" (IST) for determination of absorption coefficient and refractive index spectra of amorphous silicon (a-Si:H) and related thin film materials. The technique is based on computer analysis of measurements of optical transmission and specular reflection (T & R) of thin films (including the films on substrates) over a wide range of the incident photon energies (0.5-2.8 eV) using carefully controlled spectrometer conditions. IST is used to investigate the absorption spectrum in the sub-gap energy range (0.8-1.6 eV) of intrinsic and phosphorous-doped a-Si:H, "polymorphous-Si:H," and microcrystalline silicon films. The enhanced sensitivity of the technique over conventional analysis of T & R data results from utilization of interference to obtain absorption coefficient values at the maxima of transmission. The factors limiting the accuracy of the calculated absorption coefficient are discussed in detail. Measurement on films of thickness ranging from 0.1 to 5 μm identifies that the sub-gap absorption in these films arises from the bulk rather than the surface. A set of samples prepared under widely different conditions that appear to have overlapping (α=20 cm-1) sub-gap absorption spectra measured using photo-thermal deflection spectroscopy (PDS), reveal significant differences (α=10 to 100 cm-1) using IST. Changes (factor of 2) in sub-gap absorption spectra due to light soaking are also clearly observable using IST.

  3. Organic crystalline films for optical applications and related methods of fabrication

    NASA Technical Reports Server (NTRS)

    Leyderman, Alexander (Inventor); Cui, Yunlong (Inventor)

    2003-01-01

    The present invention provides organic single crystal films of less than 20 .mu.m, and devices and methods of making such films. The crystal films are useful in electro-optical applications and can be provided as part of an electro-optical device which provides strength, durability, and relative ease of manipulation of the mono-crystalline films during and after crystal growth.

  4. Optical reflectance in free-standing smectic films

    NASA Astrophysics Data System (ADS)

    Śliwa, Izabela

    2016-03-01

    We have carried out a numerical study of the structural, thermodynamic and optical properties of the partially fluorinated 5-n-alkyl-2-(4-n-(perfluoroalkyl-metheleneoxy)phenyl) free-standing smectic film in air under the action of the external electric field E. Calculations, based upon the extended McMillan‧s mean-field theory with anisotropic forces, show a stepwise reduction of the value of the Helmholtz free energy and the reflectivity of the partially fluorinated smectic film in air, as the temperature is raised above the bulk smectic-A-isotropic transition value. It has been shown, by solving the self-consistent nonlinear equations for the orientational and translational order parameters, that the electric field E may not only affect the layer-thinning transition sequences, but also change the first multilayer jump in the film thickness, whereas practically does not affect the reflectivity of the partially fluorinated smectic film in air. The partially fluorinated LC compounds reveal a compression of a smectic layer spacing during the layer-thinning transitions which is supported by the negative values of the thermal expansion coefficient.

  5. Perovskite-type oxide thin film integrated fiber optic sensor for high-temperature hydrogen measurement.

    PubMed

    Tang, Xiling; Remmel, Kurtis; Lan, Xinwei; Deng, Jiangdong; Xiao, Hai; Dong, Junhang

    2009-09-15

    Small size fiber optic devices integrated with chemically sensitive photonic materials are emerging as a new class of high-performance optical chemical sensor that have the potential to meet many analytical challenges in future clean energy systems and environmental management. Here, we report the integration of a proton conducting perovskite oxide thin film with a long-period fiber grating (LPFG) device for high-temperature in situ measurement of bulk hydrogen in fossil- and biomass-derived syngas. The perovskite-type Sr(Ce(0.8)Zr(0.1))Y(0.1)O(2.95) (SCZY) nanocrystalline thin film is coated on the 125 microm diameter LPFG by a facile polymeric precursor route. This fiber optic sensor (FOS) operates by monitoring the LPFG resonant wavelength (lambda(R)), which is a function of the refractive index of the perovskite oxide overcoat. At high temperature, the types and population of the ionic and electronic defects in the SCZY structure depend on the surrounding hydrogen partial pressure. Thus, varying the H(2) concentration changes the SCZY film refractive index and light absorbing characteristics that in turn shifts the lambda(R) of the LPFG. The SCZY-coated LPFG sensor has been demonstrated for bulk hydrogen measurement at 500 degrees C for its sensitivity, stability/reversibility, and H(2)-selectivity over other relevant small gases including CO, CH(4), CO(2), H(2)O, and H(2)S, etc.

  6. Silicon-integrated thin-film structure for electro-optic applications

    DOEpatents

    McKee, Rodney A.; Walker, Frederick Joseph

    2000-01-01

    A crystalline thin-film structure suited for use in any of an number of electro-optic applications, such as a phase modulator or a component of an interferometer, includes a semiconductor substrate of silicon and a ferroelectric, optically-clear thin film of the perovskite BaTiO.sub.3 overlying the surface of the silicon substrate. The BaTiO.sub.3 thin film is characterized in that substantially all of the dipole moments associated with the ferroelectric film are arranged substantially parallel to the surface of the substrate to enhance the electro-optic qualities of the film.

  7. Chemical and optical properties of thermally evaporated manganese oxide thin films

    SciTech Connect

    Al-Kuhaili, M. F.

    2006-09-15

    Manganese oxide thin films were deposited using thermal evaporation from a tungsten boat. Films were deposited under an oxygen atmosphere, and the effects of thickness, substrate temperature, and deposition rate on their properties were investigated. The chemical properties of the films were studied using x-ray photoelectron spectroscopy and x-ray fluorescence. The optical properties were determined from normal-incidence transmittance and reflectance. Based on the chemical and optical characterizations, the optimum conditions for the deposition of the films were investigated. Subsequently, the optical properties (refractive index, extinction coefficient, and band gap) of these films were determined.

  8. Optical properties of dielectric thin films including quantum dots

    NASA Astrophysics Data System (ADS)

    Flory, F.; Chen, Y. J.; Lee, C. C.; Escoubas, L.; Simon, J. J.; Torchio, P.; Le Rouzo, J.; Vedraine, S.; Derbal-Habak, Hassina; Ackermann, Jorg; Shupyk, Ivan; Didane, Yahia

    2010-08-01

    Depending on the minimum size of their micro/nano structure, thin films can exhibit very different behaviors and optical properties. From optical waveguides down to artificial anisotropy, through diffractive optics and photonic crystals, the application changes when decreasing the minimum feature size. Rigorous electromagnetic theory can be used to model most of the components but when the size is of a few nanometers, quantum theory has also to be used. These materials including quantum structures are of particular interest for other applications, in particular for solar cells, because of their luminescent and electronic properties. We show that the properties of electrons in multiple quantum wells can be easily modeled with a formalism similar to that used for multilayer waveguides. The effects of different parameters, in particular coupling between wells and well thickness dispersion, on possible discrete energy levels or energy band of electrons and on electron wave functions is given. When such quantum confinement appears the spectral absorption and the extinction coefficient dispersion with wavelength is modified. The dispersion of the real part of the refractive index can then be deduced from the Kramers- Krönig relations. Associated with homogenization theory this approach gives a new model of refractive index for thin films including quantum dots. Absorption spectra of samples composed of ZnO quantum dots in PMMA layers are in preparation are given.

  9. Optical properties of dielectric thin films including quantum dots.

    PubMed

    Flory, François; Chen, Yu-Jen; Lee, Cheng-Chung; Escoubas, Ludovic; Simon, Jean-Jacques; Torchio, Philippe; Le Rouzo, Judikaël; Vedraine, Sylvain; Derbal-Habak, Hassina; Shupyk, Ivan; Didane, Yahia; Ackermann, Jörg

    2011-03-20

    Depending on the minimum size of their micro/nanostructure, thin films can exhibit very different behaviors and optical properties. From optical waveguides down to artificial anisotropy, through diffractive optics and photonic crystals, the application changes when decreasing the minimum feature size. Rigorous electromagnetic theory can be used to model most of the components, but, when the size is a few nanometers, quantum theory also has to be used. The materials, including quantum structures, are of particular interest for many applications, in particular for solar cells because of their luminescent and electronic properties. We show that the properties of electrons in periodic and nonperiodic multiple quantum well structures can be easily modeled with a formalism similar to that used for multilayer waveguides. The effects of different parameters, in particular the coupling between wells and well thickness dispersion, on possible discrete energy levels or the energy band of electrons and on electron wave functions are given. When such quantum confinement appears, the spectral absorption and extinction coefficient dispersion with wavelength are modified. The dispersion of the real part of the refractive index can be deduced from the Kramers-Kronig relations. Associated with homogenization theory, this approach gives a new model of the refractive index for thin films including quantum dots. The bandgap of ZnO quantum dots in solution obtained from the absorption spectrum is in good agreement with our calculation.

  10. Optical study of thin-film photovoltaic cells with apparent optical path length

    NASA Astrophysics Data System (ADS)

    Cho, Changsoon; Jeong, Seonju; Lee, Jung-Yong

    2016-09-01

    Extending the insufficient optical path length (OPL) in thin-film photovoltaic cells (PVs) is the key to achieving a high power conversion efficiency (PCE) in devices. Here, we introduce the apparent OPL (AOPL) as a figure of merit for light absorbing capability in thin-film PVs. The optical characteristics such as the structural effects and angular responses in thin-film PVs were analyzed in terms of the AOPL. Although the Lambertian scattering surface yields a broadband absorption enhancement in thin-film PVs, the enhancement is not as effective as in thick-film PVs. On the other hand, nanophotonic schemes are introduced as an approach to increasing the single-pass AOPL by inducing surface plasmon resonance. The scheme using periodic metal gratings is proved to increase the AOPL in a narrow wavelength range and specific polarization, overcoming the Yablonovitch limit. The AOPL calculation can be also adopted in the experimental analysis and a maximum AOPL of 4.15d (where d is the active layer thickness) is exhibited in the absorption band edge region of PTB7:PC70BM-based polymer PVs.

  11. Optical transmission in thin films of vanadium compounds

    NASA Astrophysics Data System (ADS)

    Karimov, Kh. S.; Mahroof-Tahir, M.; Saleem, M.; Ahmad, N.; Rashid, A.

    2014-07-01

    Thin films of five vanadium compounds/composite: (1) VO2(3-fl) (3-fl = 3-Hydroxyflavone), (2) VO(pbd)2 (pbd = 1-Phenyl-1, 3-butadione), (3) VO(dbm)2 (dbm = Dibenzoylmethane), (4) VPc (Vanadyl Phthalocyanine) and (5) V2O5-PEPC (V2O5- poly-N-epoxypropylcarbazole composite), were deposited by the drop-casting method from the solution in benzene. The transmittance—irradiance relationships were investigated and the transmission in the visible spectrum and optical images were obtained as well. It was found that the transmittance of the VO2(3-fl), VO(pbd)2, VO(dbm)2 and VPc, was practically independent of the irradiance; whereas the transmittance of V2O5-PEPC decreased by 4% for thin and 9% for thick films with an increase of the irradiance.

  12. Optical bandgap determination of ultrathin amorphous films and superlattices

    NASA Astrophysics Data System (ADS)

    Siontas, Stylianos; Liu, Pei; Longo, Paolo; Zaslavsky, Alexander; Pacifici, Domenico

    Quantum size confinement effects determine the optical bandgap of ultrathin <5 nm amorphous films and superlattices. Although widely used, the standard experimental approach of combining normal-incidence reflectance and transmittance measurements with a single-pass absorption model may not always provide reliable results. By using ultra-thin amorphous germanium (a-Ge) layers down to d = 2 nm thickness as an experimental platform, we show that a multiple-reflection interference model is necessary to provide a more accurate extraction of the absorption coefficient. We also compare the two most frequently-used analytical models (Tauc and Cody) used to extract the optical bandgap from the measured absorption coefficient and clearly demonstrate that the Cody model provides a more reliable bandgap dependence on d. Finally, we apply our proposed method to experimentally determine the optical bandgap of a-Ge/SiO2 superlattices with alternating layers of a Ge and SiO2 ranging from 2 to 30 nm. Such superlattice structures enable additional control over the optical bandgap that may prove useful for the fabrication of high-efficiency photodetectors and solar cells in the optical and near-infrared spectral ranges.

  13. Structural and optical investigation of Te-based chalcogenide thin films

    NASA Astrophysics Data System (ADS)

    Sharma, Rita; Sharma, Shaveta; Chander, Ravi; Kumar, Praveen; Thangaraj, R.; Mian, M.

    2015-05-01

    We report the structural and optical properties of thermally evaporated Bi2Te3, In2Te3 and InBiTe3 films by using X-ray diffraction, optical and Raman Spectroscopy techniques. The as-prepared thin films were found to be Semi-crystalline by X-ray diffraction. Particle Size and Strain has been calculated from XRD data. The optical constants, film thickness, refractive index and optical band gap (Eg) has been reported for In2Te3, InBiTe3 films. Raman Spectroscopy was performed to investigate the effect of Bi, In, on lattice vibration and chemical bonding in Te based chalcogenide glassy alloys.

  14. Monitoring of diisopropyl fluorophosphate hydrolysis by fluoride-selective polymeric films using absorbance spectroscopy.

    PubMed

    Ramanathan, Madhumati; Wang, Lin; Wild, James R; Meyerhoff, Mark E; Meyeroff, Mark E; Simonian, Aleksandr L

    2010-05-14

    In this study, a novel system for the detection and quantification of organofluorophosphonates (OFP) has been developed by using an optical sensing polymeric membrane to detect the fluoride ions produced upon OFP hydrolysis. Diisopropyl fluorophosphate (DFP), a structural analogue of type G chemical warfare agents such as Sarin (GB) and Soman (GD), is used as the surrogate target analyte. An optical sensing fluoride ion selective polymeric film was formulated from plasticized PVC containing aluminum(III) octaethyl porphyrin and ETH 7075 chromoionophore (Al[OEP]-ETH 7075). Selected formulations were used to detect the fluoride ions produced by the catalytic hydrolysis of DFP by the enzyme organophosphate hydrolase (OPH, EC 3.1.8.1). The changes in absorbance that corresponded to the deprotonated state of chromoionophore within the film results from simultaneous coextraction of fluoride and protons as DFP hydrolysis takes place in the solution phase in contact with the film. The developed sensing system demonstrates excellent sensitivity for concentrations as low as 0.1microM DFP.

  15. Monitoring of Diisopropyl Fluorophosphate Hydrolysis by Fluoride-Selective Polymeric Films Using Absorbance Spectroscopy

    PubMed Central

    Ramanathan, Madhumati; Wang, Lin; Wild, James R.; Meyeroff, Mark E.; Simonian, Aleksandr L.

    2012-01-01

    In this study, a novel system for the detection and quantification of organofluorophosphonates (OFP) has been developed by using an optical sensing polymeric membrane to detect the fluoride ions produced upon OFP hydrolysis. Diisopropyl fluorophosphate (DFP), a structural analogue of Type G Chemical Warfare Agents such as Sarin (GB) and Soman (GD), is used as the surrogate target analyte. An optical sensing fluoride-ion-selective polymeric film was formulated from plasticized PVC containing aluminum(III) octaethylporphyrin and ETH 7075 chromoionophore (Al[OEP]-ETH 7075). Selected formulations were used to detect the fluoride ions produced by the catalytic hydrolysis of DFP by the enzyme organophosphate hydrolase (OPH, EC 3.1.8.1). The changes in absorbance that corresponded to the deprotonated state of chromoionophore within the film results from simultaneous co-extraction of fluoride and protons as DFP hydrolysis takes place in the solution phase in contact with the film. The developed sensing system demonstrates excellent sensitivity for concentrations as low as 0.1 µM DFP. PMID:20441875

  16. Multiple spectrum analysis and evaluation for optical constants of HfO2 thin films

    NASA Astrophysics Data System (ADS)

    Liu, Dandan; Liu, Huasong; Jiang, Chenghui; Jiang, Yugang; Wang, Lishuan; Zhao, Zhihong; Ji, Yiqin

    2014-08-01

    HfO2 thin films were deposited on ZS1 silica by Ion Beam Sputtering (IBS) technique. Optical constants of HfO2 thin films were obtained by multiple spectrum analysis method, which combined the transmittance spectrum and ellipsometry spectrum of the film. The refractive index and extinction coiefficient of HfO2 thin films were evaluated by etching experiments of the film. The analysis spectral range was between 250nm and 850nm.

  17. Optical properties of dielectric films dispersed with metal nanoparticles and applications to optically functional materials

    NASA Astrophysics Data System (ADS)

    Wakaki, Moriaki; Yokoyama, Eisuke

    2010-12-01

    Nanoparticles of noble metals exhibit variety of colors in the visible light region due to a surface plasmon resonance. The size-induced properties of nanoparticles enable addition of flexibility to existing systems in many areas. To design a material with desired electrical and optical properties is the aim in many composite materials. In this paper, we report the preparation and characterization of silver nanoparticles in SiO2, TiO2 and ZrO2 films and gold nanoparticles in TiO2 and ZrO2 films. To analyze the dielectric characteristic of the metal-dielectric nanocomposite film, three kinds of matrices with a different refractive index were compared. Titanium dioxide (TiO2) is one of the most promising photocatalysts and actively used in various practical applications. However, only a narrow band in the ultraviolet region of solar light, about 3-4%, is available for photocatalytic reaction. Therefore, the development of TiO2 photocatalysts with higher photoelectric conversion efficiency for visible light is required. Plasmon-induced photocatalytic activity in the ultraviolet and visible light region was studied for the TiO2 thin film dispersed with gold nanoparticles. Photocatalytic activity of Au/TiO2 film was analyzed by degradation of stearic acid, and compared with non-doped TiO2film.

  18. Optical properties of dielectric films dispersed with metal nanoparticles and applications to optically functional materials

    NASA Astrophysics Data System (ADS)

    Wakaki, Moriaki; Yokoyama, Eisuke

    2011-08-01

    Nanoparticles of noble metals exhibit variety of colors in the visible light region due to a surface plasmon resonance. The size-induced properties of nanoparticles enable addition of flexibility to existing systems in many areas. To design a material with desired electrical and optical properties is the aim in many composite materials. In this paper, we report the preparation and characterization of silver nanoparticles in SiO2, TiO2 and ZrO2 films and gold nanoparticles in TiO2 and ZrO2 films. To analyze the dielectric characteristic of the metal-dielectric nanocomposite film, three kinds of matrices with a different refractive index were compared. Titanium dioxide (TiO2) is one of the most promising photocatalysts and actively used in various practical applications. However, only a narrow band in the ultraviolet region of solar light, about 3-4%, is available for photocatalytic reaction. Therefore, the development of TiO2 photocatalysts with higher photoelectric conversion efficiency for visible light is required. Plasmon-induced photocatalytic activity in the ultraviolet and visible light region was studied for the TiO2 thin film dispersed with gold nanoparticles. Photocatalytic activity of Au/TiO2 film was analyzed by degradation of stearic acid, and compared with non-doped TiO2film.

  19. Radiative performance of rare earth garnet thin film selective emitters

    SciTech Connect

    Lowe, R.A.; Chubb, D.L.; Good, B.S.

    1994-08-01

    In this paper the authors present the first emitter efficiency results for the thin film 40 percent Er-1.5 percent Ho YAG (Yttrium Aluminum Garnet, Y3Al5O12) and 25 percent Ho YAG selective emitter at 1500 K with a platinum substrate. Spectral emittance and emissive power measurements were made (1.2 less than lambda less than 3.2 microns). Emitter efficiency and power density are significantly improved with the addition of multiple rare earth dopants. Predicted efficiency results are presented for an optimized (equal power density in the Er, (4)I[sub 15/2]-(4)I[sub 13/2] at 1.5 microns, and Ho, (5)I[sub 7]-(5)I[sub 8] at 2.0 micron emission bands) Er-Ho YAG thin film selective emitter.

  20. Radiative Performance of Rare Earth Garnet Thin Film Selective Emitters

    NASA Technical Reports Server (NTRS)

    Lowe, Roland A.; Chubb, Donald L.; Good, Brian S.

    1994-01-01

    In this paper we present the first emitter efficiency results for the thin film 40 percent Er-1.5 percent Ho YAG (Yttrium Aluminum Garnet, Y3Al5O12) and 25 percent Ho YAG selective emitter at 1500 K with a platinum substrate. Spectral emittance and emissive power measurements were made (1.2 less than lambda less than 3.2 microns). Emitter efficiency and power density are significantly improved with the addition of multiple rare earth dopants. Predicted efficiency results are presented for an optimized (equal power density in the Er, (4)I(sub 15/2)-(4)I(sub 13/2) at 1.5 microns, and Ho, (5)I(sub 7)-(5)I(sub 8) at 2.0 micron emission bands) Er-Ho YAG thin film selective emitter.

  1. X ray, extreme and far ultraviolet optical thin films for space applications

    NASA Technical Reports Server (NTRS)

    Zukic, Muamer; Torr, Douglas G.; Kim, Jongmin

    1993-01-01

    Far and extreme ultraviolet optical thin film filters find many uses in space astronomy, space astrophysics, and space aeronomy. Spacebased spectrographs are used for studying emission and absorption features of the earth, planets, sun, stars, and the interstellar medium. Most of these spectrographs use transmission or reflection filters. This requirement has prompted a search for selective filtering coatings with high throughput in the FUV and EUV spectral region. Important progress toward the development of thin film filters with improved efficiency and stability has been made in recent years. The goal for this field is the minimization of absorption to get high throughput and enhancement of wavelength selection. The Optical Aeronomy Laboratory (OAL) at the University of Alabama in Huntsville has recently developed the technology to determine optical constants of bulk and film materials for wavelengths extending from x-rays (0.1 nm) to the FUV (200 nm), and several materials have been identified that were used for designs of various optical devices which previously have been restricted to space application in the visible and near infrared. A new design concept called the Pi-multilayer was introduced and applied to the design of optical coatings for wavelengths extending from x-rays to the FUV. Section 3 of this report explains the Pi-multilayer approach and demonstrates its application for the design and fabrication of the FUV coatings. Two layer Pi-stacks have been utilized for the design of reflection filters in the EUV wavelength range from 70 - 100 nm. In order to eliminate losses due to the low reflection of the imaging optics and increase throughput and out-of-band rejection of the EUV instrumentation we introduced a self-filtering camera concept. In the FUV region, MgF2 and LiF crystals are known to be birefringent. Transmission polarizers and quarterwave retarders made of MgF2 or LiF crystals are commercially available but the performances are poor. New

  2. Pharmaceutical Film Coating Catalog for Spectral Domain Optical Coherence Tomography.

    PubMed

    Lin, Hungyen; Dong, Yue; Markl, Daniel; Zhang, Zijian; Shen, Yaochun; Zeitler, J Axel

    2017-10-01

    Optical coherence tomography (OCT) has recently been demonstrated to measure the film coating thickness of pharmaceutical tablets and pellets directly. The results enable the analysis of inter- and intra-tablet coating variability at an off-line and in-line setting. To date, only a few coating formulations have been tried and there is very little information on the applicability of OCT to other coatings. As it is well documented that optical methods including OCT are prone to scattering leading to limited penetration, some pharmaceutical coatings may not be measurable altogether. This study presents OCT measurements of 22 different common coatings for the assessment of OCT applicability. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  3. Magneto-optic rotation and ellipticity of ultrathin ferromagnetic films

    NASA Astrophysics Data System (ADS)

    Moog, E. R.; Zak, J.; Huberman, M. L.; Bader, S. D.

    1989-05-01

    Magneto-optic rotation φ' and ellipticity φ'' values are reported as a function of thickness for 0-400 Å of bcc Fe(100) epitaxially deposited on Au(100) for both s- and p-polarized He-Ne laser light. The values are derived from a formula that connects φ' and φ'' with our recently reported longitudinal Kerr-effect measurements of φm=(φ'2+φ''2)1/2 and the parameters of two optical compensators that are used to convert ellipticity to rotation. The measurements were made in situ through an ultrahigh-vacuum window; our approach eliminates the effect of the window birefringence. The dominant contribution to φm reverses from being φ'' in the ultrathin limit to being φ' in the thick-film limit. Also, in the 0-30 Å range, the rotation remains near zero while the ellipticity increases linearly.

  4. Controlling the optical properties of sputtered-deposited LixV2O5 films

    NASA Astrophysics Data System (ADS)

    Muñoz-Castro, M.; Berkemeier, F.; Schmitz, G.; Buchheit, A.; Wiemhöfer, H.-D.

    2016-10-01

    This study examines the influence of lithium intercalation on the optical properties of vanadium pentoxide films. The films with a thickness between 400 and 1000 nm were prepared by DC magnetron sputter deposition. Cyclic voltammetry and chronopotentiometry were used to set a well defined lithiation state of the LixV2O5 films between x = 0 and x = 1. The optical properties of these films were measured by optical reflectometry in the wavelength range between 500 and 1700 nm. From the reflectance data, the refractive index and the extinction coefficient of the films were finally calculated as a function of the wavelength using Cauchy's dispersion model. The results confirm that the optical behavior of LixV2O5 films varies significantly upon lithium insertion. It is demonstrated that the changes produced in the optical properties are completely reversible within the limits of permanent structure changes.

  5. On the Structure, Electrical and Optical Properties of TiO2 Sputtered Thin Films

    NASA Astrophysics Data System (ADS)

    Ashour, A.

    Titanium oxide thin films were prepared by sputtering technique onto glass substrates at room temperature (RT). The structure of the films was confirmed using X-ray diffraction (XRD) and revealed the stoichiometry with an O and Ti ratio of 2. The deposited films at RT were found to be amorphous and the films annealed at 300 and 400°C for 2 h were crystalline with orthorhombic structure. The lattice constants and grain size of the film are calculated. The electrical resistivity was found to depend on the film thickness and decreased with increasing the film thicknesses. The optical constants of the films such as the refractive index, extinction coefficient, and absorption coefficient were also determined using the optical transmittance measurements, and the results were discussed. The optical band gap varies from 3.2 to 3.5 eV as a function of oxygen/argon ratios.

  6. Vanadium dioxide thin films for smart windows: optical design and performance improvement

    NASA Astrophysics Data System (ADS)

    He, Xinfeng; Gu, Congcong; Chen, Fei; Xu, Xiaofeng

    2013-12-01

    The high quality vanadium dioxide (VO2) thin films have been fabricated successfully on sapphire by a simple novel sputtering oxidation coupling (SOC) method. Transmittance spectra of vanadium dioxide film have been measured between 25 °C and 90 °C. The thin film samples exhibit a good insulator-metal transition near room temperature. The optical constants of VO2 thin film samples were derived by fitting the transmittance spectra using the Drude-Lorentz model. In order to improve the transition efficiency, the thin film thickness was optimized by the optical design. The calculated results with different thin film thickness show that VO2 thin film with 84 nm owns a maximums value of the transition efficiency. This research will promote VO2 thin film optical performance improvement for the smart windows.

  7. Selective permeation of hydrogen gas using cellulose nanofibril film.

    PubMed

    Fukuzumi, Hayaka; Fujisawa, Shuji; Saito, Tsuguyuki; Isogai, Akira

    2013-05-13

    Biobased membranes that can selectively permeate hydrogen gas have been developed from aqueous dispersions of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCN) prepared from wood cellulose: TOCN-coated plastic films and self-standing TOCN films. Compared with TOCNs with sodium, lithium, potassium, and cesium carboxylate groups, TOCN with free carboxyl groups (TOCN-COOH) had much high and selective H2 gas permeation performance. Because permeabilities of H2, N2, O2, and CO2 gases through the membranes primarily depended on their kinetic diameters, the gas permeation behavior of the various TOCNs can be explained in terms of a diffusion mechanism. Thus, the selective H2 gas permeability for TOCN-COOH was probably due to a larger average size in free volume holes present between nanofibrils in the layer and film than those of other TOCNs with metal carboxylate groups. The obtained results indicate that TOCN-COOH membranes are applicable as biobased H2 gas separation membranes in fuel cell electric power generation systems.

  8. Transition-metal-nitride films for optical applications

    NASA Astrophysics Data System (ADS)

    Ribbing, Carl-Gustaf; Roos, Arne

    1997-10-01

    The three transition metal nitrides TiN, ZrN and HfN have remarkably high stability due to their bonding: a mixture of covalent and ionic contributions. The optical properties of these nitride compounds are free-electron like to a surprisingly large extent, in particular in comparison with the corresponding carbides. It is argued that the interband optical excitations of the d-electrons are restricted by selection rules, resulting in a Drude like behavior of these d-electron compounds. Hitherto, one of the main optical applications has been as opaque, wear-resistant replacements for gold-coatings. This review includes the efforts to study, understand and enhance the optical selectivity of group IVB transition metal nitrides as the selective surface in high temperature thermal solar absorbers, as the metal layer in LE-coatings on energy-efficient or solar control windows and as a Langmuir probe coating. The reflectance edge is not in the optimum position for absorber applications and attempts to shift it with alloying were unsuccessful. Recent development of inhomogeneous, cermet- type nitrides hold some promise. The LE-coatings will not reach as high selectivity as the current noble metal based multilayers, but many find use in aggressive environments because of their excellent stability.

  9. Magneto-optical coupling in ferromagnetic thin films investigated by vector-magneto-optical generalized ellipsometry

    NASA Astrophysics Data System (ADS)

    Mok, K.; Kovács, G. J.; McCord, J.; Li, L.; Helm, M.; Schmidt, H.

    2011-09-01

    We performed generalized Mueller matrix ellipsometry measurements in a magnetic field of arbitrary orientation and magnitude up to 400 mT at room temperature and probed the magneto-optical response of capped, ferromagnetic Fe, Ni20Fe80, Co, Ni80Fe20, and Ni thin films on ZnO substrates in the spectral range from 300 to 1100 nm. We determined the off-diagonal elements in the magneto-optical dielectric tensor under saturated magnetization conditions in the sample surface plane via a model analysis. The off-diagonal elements depend on the net spin polarization and the electronic band structure of the ferromagnetic thin films. For the pure ferromagnetic metals Fe, Co, and Ni, the converted off-diagonal elements agree well with the reported experimental optical conductivity data. As a result we use the extracted wavelength-dependent magneto-optical coupling constant to predict the wavelength-dependent magneto-optical response of different Ni/Fe multilayer structures.

  10. Autoindicating optical properties of laccase as the base of an optical biosensor film for phenol determination.

    PubMed

    Sanz, J; de Marcos, S; Galbán, J

    2012-08-01

    In the context of sustainable analytical chemistry, phenol has been determined through its enzymatic reaction with laccase. The method has been studied and optimized through the autoindicating optical properties of laccase both by intrinsic molecular absorption and fluorescence. The method shows a linear range from 9.79·10(-6) to 7.50·10(-4) M with a relative standard deviation of 1.07 %. The molecular absorption methodology has been implemented in a polyacrylamide film for the design of an autoindicating optical sensor. In order to increase the lifetime of the sensor, the reversibility study of the enzymatic reaction has proposed, as a novelty, the regeneration of laccase with an oxidase-type enzyme (glucose oxidase). The lifetime of the sensor film has improved from 15 to 30 measurements. The reaction mechanism has also been studied and confirmed by fluorescence and molecular absorption. The method leads to the determination of phenol in environmental samples.

  11. Correlated electron perovskite films for optical sensing applications

    NASA Astrophysics Data System (ADS)

    Schultz, Andrew M.; Brown, Thomas D.; Ohodnicki, Paul R.

    2015-10-01

    Advanced power generation technologies including solid oxide fuel cells require advancements in sensor technologies for efficient operation. Gas sensors for SOFC anode streams must be stable in high temperature and under reducing atmospheres. Optical sensing technologies offer the potential for good stability and sensing response under harsh conditions but are relatively new as compared to alternative sensing approaches and require significant developments in underlying device and enabling materials technology. In this paper, the near infrared optical sensing response of La0.8Sr0.2MnO3, a representative correlated perovskite material, is presented. Hydrogen sensing performance was measured in laboratory scale sensing experiments in the range of 1-4% hydrogen. The effect of oxygen on sensor recovery behavior was also examined. The films show a large, recoverable response to the introduction of hydrogen to the gas stream. The results presented here suggest this unique class of materials is a strong candidate for future sensor development efforts targeted at optical sensor applications but also requires additional fundamental research to understand the mechanistic origin of observed optical sensing responses.

  12. Optical control of multi-stage thin film solar cell production

    DOEpatents

    Li, Jian; Levi, Dean H.; Contreras, Miguel A.; Scharf, John

    2016-05-17

    Embodiments include methods of depositing and controlling the deposition of a film in multiple stages. The disclosed deposition and deposition control methods include the optical monitoring of a deposition matrix to determine a time when at least one transition point occurs. In certain embodiments, the transition point or transition points are a stoichiometry point. Methods may also include controlling the length of time in which material is deposited during a deposition stage or controlling the amount of the first, second or subsequent materials deposited during any deposition stage in response to a determination of the time when a selected transition point occurs.

  13. Optoelectronic scalable substrates based on film/Z-connection and its application to film optical link module (FOLM)

    NASA Astrophysics Data System (ADS)

    Yoshimura, Tetsuzo; Roman, James; Takahashi, Yasuhito; Lee, Michael; Chou, Bill; Beilin, Solomon I.; Wang, Wen-Chou V.; Inao, Masaaki

    2000-04-01

    We propose a new concept of optoelectronic (OE) interconnect hardware 'OE Scalable Substrate (OE-SS)' and 'Film Optical Link Module (FOLM)', which have potentiality to remove optics excess. The structure is as follows: OE-films, in which waveguides, thin-film OE devices, LSIs, capacitor chips etc. are integrated with via/pad/electrode, are stacked by electrical joints (Z-connections). This gives rise to standardized-interface capability and scalability. Using one basic technology 'film/Z-connection', all levels of interconnection will be achieved, including massive parallel optical link, inter-board optical connect, and 3D- stack-OE-MCM. We prose a new process 'Device Integration with Self-Organizing Transfer', which is essential for low- cost OE-SS and FOLM, especially for WDM applications.

  14. Determination of refractive index, thickness, and the optical losses of thin films from prism-film coupling measurements.

    PubMed

    Cardin, Julien; Leduc, Dominique

    2008-03-01

    We present a method of analysis of prism-film coupler spectroscopy based on the use of transfer matrix and genetic algorithm, which allows the simultaneous determination of refractive index, thickness, and optical losses of the measured layer.

  15. Optical studies on electron beam evaporated lithium triborate films.

    PubMed

    Mohandoss, R; Dhanuskodi, S; Sanjeeviraja, C

    2012-10-01

    Lithium triborate (LB3) has numerous applications in scintillator for neutron detection, laser weapon and communication. LB3 films have been prepared by electron beam evaporation technique under a pressure of 1×10(-5) mbar on glass substrate at 323 K for 4 min. The crystallographic orientations and the lattice parameters (a=8.55 (2); b=5.09 (2); c=7.39 (2)Å) were determined by powder XRD indicating the (111) preferential orientation of the film. The lower cut off wavelength at 325 nm with 75% transparency was measured from the UV-vis spectrum. The optical constants extinction coefficient (K), reflectance (R), the linear refractive index (1.34) and the optical energy band gap (~4.0 eV) were estimated. The photoluminescence spectrum shows the emission peak in the visible region with low concentration of oxygen defects. LB3 is found to be second harmonic generation (SHG) active using a Q-switched Nd:YAG laser (1064 nm, 9 ns, 10 Hz). The nonlinear refractive index (n(2)~10(-16) cm(2)/W) and nonlinear absorption coefficient (β~10(-2) cm/W) reveal (Z-scan technique) that the material has negative nonlinearity and self-focusing nature. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Optical thin films deposition by MDECR-PECVD

    NASA Astrophysics Data System (ADS)

    Haj Ibrahim, Bicher; Bulkin, Pavel; Daineka, Dmitri; Drévillon, Bernard

    2005-09-01

    We designed and built Matrix Distributed ECR (MDECR) PECVD reactor dedicated for dielectric filters deposition and equipped it with multiple sensors for process control. Planar matrix geometry of plasma source is based on electron cyclotron resonance effect at 2.45 GHz microwave frequency and provides scalability of the deposition on large area substrates. High (up to 5 nm/sec) deposition rate obtained due to high dissociation efficiency and careful design of the gas injection system. Optical emission spectroscopy, quadrupole mass-spectrometry and spectroscopic and multi-channel kinetic ellipsometry are installed for in-situ studies and control of the film deposition. We performed studies of the nature of high-density plasma discharge in silane, oxygen and nitrogen mixture and correlated its properties with optical and physical properties of deposited materials. To demonstrate the capabilities, a wide band gradient index antireflection coating on glass was realized by deposition of SiOxNy alloy thin films. The predefined variation of an index in a profile is obtained by changing the flows of precursors. Real-time control is performed with multi-channel kinetic ellipsometry.

  17. Optical Properties of ZnO-Alloyed Nanocrystalline Films

    DOE PAGES

    Che, Hui; Huso, Jesse; Morrison, John L.; ...

    2012-01-01

    ZnO is emore » merging as one of the materials of choice for UV applications. It has a deep excitonic energy level and a direct bandgap of ~3.4 eV. Alloying ZnO with certain atomic constituents adds new optical and electronic functionalities to ZnO. This paper presents research on M g x Z n 1 − x O and Z n S 1 − x O x nanocrystalline flexible films, which enable tunable optical properties in the deep-UV and in the visible range. The ZnO and Mg 0 .3 Zn 0 .7 O films were found to have bandgaps at 3.35 and 4.02 eV, respectively. The photoluminescence of the Mg 0 .3 Zn 0 .7 O exhibited a bandedge emission at 3.95 eV, and at lower energy 3.38 eV due to the limited solubility inherent to these alloys. ZnS 0 .76 O 0 .24 and ZnS 0 .16 O 0 .84 were found to have bandgaps at 3.21 and 2.65 eV, respectively. The effect of nitrogen doping on ZnS 0 .16 O 0 .84 is discussed in terms of the highly lattice mismatched nature of these alloys and the resulting valence-band modification.« less

  18. Optically Thin Metallic Films for High-Radiative-Efficiency Plasmonics.

    PubMed

    Yang, Yi; Zhen, Bo; Hsu, Chia Wei; Miller, Owen D; Joannopoulos, John D; Soljačić, Marin

    2016-07-13

    Plasmonics enables deep-subwavelength concentration of light and has become important for fundamental studies as well as real-life applications. Two major existing platforms of plasmonics are metallic nanoparticles and metallic films. Metallic nanoparticles allow efficient coupling to far field radiation, yet their synthesis typically leads to poor material quality. Metallic films offer substantially higher quality materials, but their coupling to radiation is typically jeopardized due to the large momentum mismatch with free space. Here, we propose and theoretically investigate optically thin metallic films as an ideal platform for high-radiative-efficiency plasmonics. For far-field scattering, adding a thin high-quality metallic substrate enables a higher quality factor while maintaining the localization and tunability that the nanoparticle provides. For near-field spontaneous emission, a thin metallic substrate, of high quality or not, greatly improves the field overlap between the emitter environment and propagating surface plasmons, enabling high-Purcell (total enhancement >10(4)), high-quantum-yield (>50%) spontaneous emission, even as the gap size vanishes (3-5 nm). The enhancement has almost spatially independent efficiency and does not suffer from quenching effects that commonly exist in previous structures.

  19. RESEARCH ON THE ELECTRONIC AND OPTICAL PROPERTIES OF POLYMER AND OTHER ORGANIC MOLECULAR THIN FILMS

    SciTech Connect

    ALEXEI G. VITUKHNOVSKY; IGOR I. SOBELMAN - RUSSIAN ACADEMY OF SCIENCES

    1995-09-06

    Optical properties of highly ordered films of poly(p-phenylene) (PPP) on different substrates, thin films of mixtures of conjugated polymers, of fullerene and its composition with polymers, molecular J-aggregates of cyanine dyes in frozen matrices have been studied within the framework of the Agreement. Procedures of preparation of high-quality vacuum deposited PPP films on different substrates (ITO, Si, GaAs and etc.) were developed. Using time-correlated single photon counting technique and fluorescence spectroscopy the high quality of PPP films has been confirmed. Dependence of structure and optical properties on the conditions of preparation were investigated. The fluorescence lifetime and spectra of highly oriented vacuum deposited PPP films were studied as a function of the degree of polymerization. It was shown for the first time that the maximum fluorescence quantum yield is achieved for the chain length approximately equal to 35 monomer units. The selective excitation of luminescence of thin films of PPP was performed in the temperature range from 5 to 300 K. The total intensity of luminescence monotonically decreases with decreasing temperature. Conditions of preparation of highly cristallyne fullerene C{sub 60} films by the method of vacuum deposition were found. Composites of C{sub 60} with conjugated polymers PPV and polyacetylene (PA) were prepared. The results on fluorescence quenching, IR and resonant Raman spectroscopy are consistent with earlier reported ultrafast photoinduced electron transfer from PPV to C{sub 60} and show that the electron transfer is absent in the case of the PA-C{sub 60} composition. Strong quenching of PPV fluorescence was observed in the PPV-PA blends. The electron transfer from PPV to PA can be considered as one of the possible mechanisms of this quenching. The dynamics of photoexcitations in different types of J-aggregates of the carbocyanine dye was studied at different temperatures in frozen matrices. The optical

  20. Electromagnetic resonances of wavelength-selective solar absorbers with film-coupled fishnet gratings

    NASA Astrophysics Data System (ADS)

    Matsuno, Yuki; Sakurai, Atsushi

    2017-02-01

    The purpose of this study is to clarify the optical characteristics of a Tungsten-SiO2-based film-coupled metamaterial with a fishnet-shaped grating, and we aim to show that this structure could potentially be used as a solar selective absorber for a solar thermophotovoltaic system. The proposed film-coupled metamaterial absorber combined with a fishnet-shaped grating shows significant enhancement in its absorption in the visible spectral region compared with a flat Tungsten surface, and it keeps its spectral emission low in the infrared region, thereby reducing radiative heat loss. The underlying mechanisms of the proposed absorber are discussed through a 3D full-wave electromagnetic simulation, the results of which are compared with that of theoretical equations. Furthermore, its spectral absorption under oblique incident light at the transverse magnetic and transverse electric waves is scrutinized. The underlying absorption mechanisms and relations between each optical resonance are discussed in this paper and will prove to be fundamental not only in the design of solar selective absorbers but also in other wavelength-selective thermal radiation controlling devices.

  1. The optical and electrical properties of silver nanowire mesh films

    NASA Astrophysics Data System (ADS)

    Khanarian, G.; Joo, J.; Liu, X.-Q.; Eastman, P.; Werner, D.; O'Connell, K.; Trefonas, P.

    2013-07-01

    We present experimental results for the transmission T, haze H, sheet resistance Rs, and its spatial fluctuations ΔRs for silver nanowire films. Mie light scattering theory of nanowires is developed to predict both T and H as a function of diameter D of wires and the surface fraction ϕs covered by the wires. Percolation theory is used to derive an equation for Rs in terms of D, the aspect ratio of wires D/L and ϕs. The critical exponent t for percolation of Rs is found to be 1.23 in close agreement with theoretical results for 2D random resistive networks (t = 1.3). These equations show the importance of both the distributions of diameter ⟨D⟩ and aspect ratio of wires ⟨D⟩⟨L⟩/⟨L2⟩ to predict the optical and electrical properties. Spatial fluctuations ΔRs/Rs can also be significant in these films and be greater than 10% as ϕs approaches the critical percolation concentration ϕc. We show that the calculated T versus Rs and H versus Rs curves are in good agreement with the experimental data. We propose figures of merit for percolating nanowire films in terms of high T, low H, and low Rs to order the quality of films for touch screen applications. The results show that D < 50 nm and L > 5 μm are needed to achieve low haze H < 1%, high transmission T > 90%, together with low Rs ˜ 100 Ω/sq for touch screen applications. Finally, we present experimental and theoretical results of the real and imaginary refractive indices of AgNW/polymer nanocomposites, and find that the Van De Hulst model is more accurate than the Maxwell Garnett models.

  2. Optical study of BST films combining ellipsometry and reflectivity

    NASA Astrophysics Data System (ADS)

    Železný, V.; Chvostová, D.; Pajasová, L.; Jelínek, M.; Kocourek, T.; Daniš, S.; Valvoda, V.

    2009-03-01

    Optical properties of plasma laser-deposited Ba 0.75Sr 0.25TiO 3 (BST) thin films have been investigated using variable angle spectroscopic ellipsometry (VASE) and near-normal spectroscopic reflectivity (NNSR) within a broad spectral range at room temperature. The samples prepared under various deposition conditions and the Si substrate coated with the structure SiO 2/TiO x/Pt were measured. The X-ray diffraction, atomic force microscopy and alpha step measurement were used for characterization of the samples. A special attention was paid to study sample texture. Both sets of experimental data (VASE and NNSR) were fitted simultaneously to obtain the optical constants (e.g. complex refractive index) and thicknesses of the films. For modeling of the experimental data in the range of transparency the Cauchy and Urbach formulas were used. The direct fit procedure and the Cody-Lorentz model were applied around and below absorption edge. In the entire spectral range the reflectivity spectra were analyzed by Kramers-Kronig analysis. The data around the absorption edge were fitted using the single-wavelength method and the absorption edge features were found up about 3.5 eV. The platinum-coated Si substrate data were fitted as a semi-infinite medium using the Drude and Lorentz oscillators model. The structure model for optical characterization of the sample included not only the BST layers and substrate but also the intermix and surface roughness layers to achieve good agreement with experimental data. The substrate structure was modeled by a simple bulk with surface roughness.

  3. Optical properties and recording characteristics of phthalocyanine-derivative LB films

    NASA Astrophysics Data System (ADS)

    Gan, Fuxi; Luo, Tao

    1993-08-01

    Langmuir-Blodgett (LB) films of tetra-neopentoxy phthalocyanine zinc and tetra-nonyl phthalocyanine copper are prepared. Their structures, optical properties, and temperature dependencies are investigated. Static optical recording tests by He-Ne laser are done in these LB films and the experimental results demonstrate that phthalocyanine derivates are useful for phase change type erasable data storage media.

  4. Optical and photoelectrical properties of nanostructured thin ZnO films for UV-sensors

    NASA Astrophysics Data System (ADS)

    Grigoryev, L. V.; Kulakov, S. V.; Nefedov, V. G.; Shakin, O. V.; Grigoryeva, M. L.; Moskalenko, S. D.

    2017-05-01

    The article presents the results investigations of the optical and photoelectric properties thin films zinc oxide obtained by the reactive ion-plasma method. It is shown that the optical and photoelectric properties of thin ZnO films has equivalent characteristics to the properties of single crystal zinc oxide and can be used to create UV-photoresistors.

  5. Influence of sputtering power on the optical properties of ITO thin films

    SciTech Connect

    K, Aijo John; M, Deepak T, Manju; Kumar, Vineetha V.

    2014-10-15

    Tin doped indium oxide films are widely used in transparent conducting coatings such as flat panel displays, crystal displays and in optical devices such as solar cells and organic light emitting diodes due to the high electrical resistivity and optical transparency in the visible region of solar spectrum. The deposition parameters have a commendable influence on the optical and electrical properties of the thin films. In this study, ITO thin films were prepared by RF magnetron sputtering. The properties of the films prepared under varying sputtering power were compared using UV- visible spectrophotometry. Effect of sputtering power on the energy band gap, absorption coefficient and refractive index are investigated.

  6. Thin Ag films. Influence of substrate and postdeposition treatment on morphology and optical properties

    SciTech Connect

    Roark, S.E.; Rowlen, K.L. )

    1994-01-15

    In an effort to understand the experimental parameters that influence thin metal film morphology and optical characteristics, thin Ag films are examined with a combination of atomic force microscopy (AFM), optical absorption, and surface-enhanced Raman spectroscopy (SERS). The morphology of 5 nm of Ag vapor deposited onto glass, derivatized glass, Formvar-coated glass, and mica is explored. The substrate is found to have a large effect on both Ag film surface morphology and optical properties. In addition, micrographs of a Ag film before and after exposure to solvent suggest solvent-induced morphological changes. 32 refs., 8 figs., 5 tabs.

  7. Potassium tantalate-niobate mixed crystal thin films for applications in nonlinear integrated optics

    NASA Astrophysics Data System (ADS)

    Jia, Yuechen; Szabados, Jan; Winkler, Markus; Breunig, Ingo; Cimalla, Volker; Kirste, Lutz; Žukauskaitė, Agnė; Buse, Karsten

    2017-06-01

    Potassium tantalate-niobate mixed crystal (KTN) thin films are promising candidates to meet the needs of integrated nonlinear optical devices for electro-optic and frequency-conversion applications. In this contribution we report on pulsed-laser-deposition growth of ferroelectric KTN films on MgO substrates. It was shown that highly-oriented KTN films are epitaxially grown as revealed by X-ray diffraction analysis. Moreover, the thermal annealing treatment can be further optimized to obtain optically smooth KTN films with RMS surface roughness as low as 1 nm.

  8. Spectroscopic ellipsometry investigations of optical anisotropy in obliquely deposited hafnia thin films

    SciTech Connect

    Tokas, R. B. Jena, Shuvendu; Thakur, S.; Sahoo, N. K.; Haque, S. Maidul; Rao, K. Divakar

    2016-05-23

    In present work, HfO{sub 2} thin films have been deposited at various oblique incidences on Si substrates by electron beam evaporation. These refractory oxide films exhibited anisotropy in refractive index predictably due to special columnar microstructure. Spectroscopic ellipsometry being a powerful tool for optical characterization has been employed to investigate optical anisotropy. It was observed that the film deposited at glancing angle (80°) exhibits the highest optical anisotropy. Further, anisotropy was noticed to decrease with lower values of deposition angles while effective refractive index depicts opposite trend. Variation in refractive index and anisotropy has been explained in light of atomic shadowing during growth of thin films at oblique angles.

  9. IR surface polariton spectroscopy as a method for studying the optical properties of ultra thin films

    NASA Astrophysics Data System (ADS)

    Vinogradov, E. A.

    2016-12-01

    Experimental results of investigation of optical properties of MgO thin films (thickness 10, 30, 100 i 300 nm) and AlN films (thickness 40 i 400 nm) on sapphire substrate are discussed. The optical phonon frequencies of these films are located in frequency region of surface polariton of sapphire. Due to the resonance between them the splitting and the shift of absorption spectra of sapphire surface polariton appear. From these experimental data it is possible to reconstruct all constants of the permittivity of both the film and substrate, the film thickness, and to specify its structure.

  10. Optical constants of electrochromic films and contrast ratio of reflective electrochromic devices.

    PubMed

    Jaing, Cheng-Chung; Tang, Chien-Jen; Chan, Chih-Chao; Lee, Kun-Hsien; Kuo, Chien-Cheng; Chen, Hsi-Chao; Lee, Cheng-Chung

    2014-02-01

    This study investigates the optical constants of WO3 electrochromic films and NiO ion-storage films in bleached and colored states and that of a Ta2O5 film used as an ion conductor. These thin films were all prepared by electron-beam evaporation and characterized using a spectroscopic ellipsometer. The spectra obtained using a spectrophotometer and those calculated from the optical constants agreed closely. An all-solid thin-film reflective electrochromic device was fabricated and discussed. Its mean contrast ratio of reflectance in the range of 400-700 nm was 37.91.

  11. Optical properties of bismuth sulfide thin film prepared by thermal evaporation method

    NASA Astrophysics Data System (ADS)

    Kachari, T.; Rahman, A.

    2015-04-01

    Two types of thin films of Bi2S3 have been prepared on chemically cleaned glass substrate by thermal evaporation technique. Either by thermal evaporation of Bi2S3 powder or by thermal evaporation of bismuth and sulfur from two separate source. (Both annealed for 3 h in air inside an oven). Optical properties of these annealed films have been studied by measuring transmittance, absorbance and reflectance of the films. Optical constants such as absorption coefficient, extinction constants, refractive index, dielectric constants etc. of both types of Bi2S3 films have been calculated. Optical band gap of type (I) and (II) films have been found to be 1.647 and 1.668 eV respectively. The crystalline structure and purity of these Bi2S3 films have been studied by taking X-ray diffraction and X-ray fluorescence spectra. Surface morphology of the films has been studied by scanning electron microscopy.

  12. Evaluation of space environmental effects on metals and optical thin films on EOIM-3

    NASA Technical Reports Server (NTRS)

    Vaughn, Jason A.; Linton, Roger C.; Finckenor, Miria M.; Kamenetzky, Rachel R.

    1995-01-01

    Metals and optical thin films exposed to the space environment on the Third Flight of the Evaluation of Oxygen Interactions with Materials (EOIM-3) payload, onboard Space Shuttle mission STS-46 were evaluated. The materials effects described in this paper include the effects of space exposure on various pure metals, optical thin films, and optical thin film metals. The changes induced by exposure to the space environment in the material properties were evaluated using bidirectional reflectance distribution function (BRDF), specular reflectance (250 nm to 2500 nm), ESCA, VUV reflectance (120 nm to 200 nm), ellipsometry, FTIR and optical properties. Using these analysis techniques gold optically thin film metal mirrors with nickel undercoats were observed to darken due to nickel diffusion through the gold to the surface. Also, thin film nickel mirrors formed nickel oxide due to exposure to both the atmosphere and space.

  13. Optical pulse synthesis using brillouin selective sideband amplification

    NASA Technical Reports Server (NTRS)

    Yao, X. Steve (Inventor)

    2002-01-01

    Techniques for producing optical pulses based on Brillouin selective sideband amplification by using a common modulation control signal to modulate both a signal beam to produce multiple sideband signals and a single pump beam to produce multiple pump beams.

  14. Thin-film fiber optic hydrogen and temperature sensor system

    DOEpatents

    Nave, S.E.

    1998-07-21

    The invention discloses a sensor probe device for monitoring of hydrogen gas concentrations and temperatures by the same sensor probe. The sensor probe is constructed using thin-film deposition methods for the placement of a multitude of layers of materials sensitive to hydrogen concentrations and temperature on the end of a light transparent lens located within the sensor probe. The end of the lens within the sensor probe contains a lens containing a layer of hydrogen permeable material which excludes other reactive gases, a layer of reflective metal material that forms a metal hydride upon absorbing hydrogen, and a layer of semi-conducting solid that is transparent above a temperature dependent minimum wavelength for temperature detection. The three layers of materials are located at the distal end of the lens located within the sensor probe. The lens focuses light generated by broad-band light generator and connected by fiber-optics to the sensor probe, onto a reflective metal material layer, which passes through the semi-conducting solid layer, onto two optical fibers located at the base of the sensor probe. The reflected light is transmitted over fiber optic cables to a spectrometer and system controller. The absence of electrical signals and electrical wires in the sensor probe provides for an elimination of the potential for spark sources when monitoring in hydrogen rich environments, and provides a sensor free from electrical interferences. 3 figs.

  15. Optical variability of X-ray-selected QSOs

    SciTech Connect

    Pica, A.J.; Webb, J.R.; Smith, A.G.; Leacock, R.J.; Bitran, M.

    1987-08-01

    Photometric data for ten X-ray-selected quasistellar objects have been obtained from archival records of the Rosemary Hill Observatory. Reliable magnitudes were obtained for seven of the ten sources and six displayed optical variations significant at the 95 percent confidence level or greater. One source appeared to exhibit optically violent behavior. Light curves and photographic magnitudes are presented and discussed. 22 references.

  16. Optical variability of X-ray-selected QSOs

    NASA Astrophysics Data System (ADS)

    Pica, Andrew J.; Webb, James R.; Smith, Alex G.; Leacock, Robert J.; Bitran, Mauricio

    1987-08-01

    Photometric data for ten X-ray-selected quasistellar objects have been obtained from archival records of the Rosemary Hill Observatory. Reliable magnitudes were obtained for seven of the ten sources and six displayed optical variations significant at the 95 percent confidence level or greater. One source appeared to exhibit optically violent behavior. Light curves and photographic magnitudes are presented and discussed.

  17. Engineering of the band gap and optical properties of thin films of yttrium hydride

    NASA Astrophysics Data System (ADS)

    You, Chang Chuan; Mongstad, Trygve; Maehlen, Jan Petter; Karazhanov, Smagul

    2014-07-01

    Thin films of oxygen-containing yttrium hydride show photochromic effect at room temperature. In this work, we have studied structural and optical properties of the films deposited at different deposition pressures, discovering the possibility of engineering the optical band gap by variation of the oxygen content. In sum, the transparency of the films and the wavelength range of photons triggering the photochromic effect can be controlled by variation of the deposition pressure.

  18. Engineering of the band gap and optical properties of thin films of yttrium hydride

    SciTech Connect

    You, Chang Chuan; Mongstad, Trygve; Maehlen, Jan Petter; Karazhanov, Smagul

    2014-07-21

    Thin films of oxygen-containing yttrium hydride show photochromic effect at room temperature. In this work, we have studied structural and optical properties of the films deposited at different deposition pressures, discovering the possibility of engineering the optical band gap by variation of the oxygen content. In sum, the transparency of the films and the wavelength range of photons triggering the photochromic effect can be controlled by variation of the deposition pressure.

  19. Ferroelectric Tungsten Bronze Bulk Crystals and Epitaxial Thin Films for Electro-Optic Device Applications

    DTIC Science & Technology

    1983-05-01

    23 FERROELECTRIC TUNGSTEN BRONZE BULK CRYSTALS AND EPITAXIAL THIN FILMS FOR ELECTRO-OPTIC DEVICE APPLICATIONS 10 CO O Semi-Annual Technical... THIN FILMS FOR ELECTRO-OPTIC DEVICE APPLICATIONS s TV^C or REPORT * pcmoo COVCHCO Semi-Annual Tec1! Rpt #1 for period 09/30/82-03/31/83...months, considerable progress has been made in several areas, including single crystal and thin film growth and characteriza- tion. The new

  20. Measurements of the optical properties of thin films of silver and silver oxide

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Sisk, Robert C.; Brown, Yolanda; Gregory, John C.; Nag, Pallob K.; Christl, Ligia

    1995-01-01

    The optical properties of silver films and their oxides are measured to better characterize such films for use as sensors for atomic oxygen. Good agreement between properties of measured pure silver films and reported optical constants is observed. Similar comparisons for silver oxide have not been possible because of a lack of reported constants, but self-consistencies and discrepancies in our measured results are described.

  1. [A reflection interference method for determining optical constants and thickness of a thin solid film].

    PubMed

    Yang, P; Xu, Z; Xu, L

    2000-06-01

    In this paper we report a simple method for deducing optical constants and thickness from the reflection interference spectrum of a thin transparent film which is on a substrate of high reflection coefficient. When a light beam is incident on the surface of the film, the reflection light beams at the front and rear faces are coherent. We calculated the optical constants and thickness of the film from the reflection spectrum. This simple method makes a directly programmable calculation possible.

  2. Optical frequency tripling with improved suppression and sideband selection.

    PubMed

    Thakur, Manoj P; Medeiros, Maria C R; Laurêncio, Paula; Mitchell, John E

    2011-12-12

    A novel optical dispersion tolerant millimetre-wave radio-over-fibre system using optical frequency tripling technique with enhanced and selectable sideband suppression is demonstrated. The implementation utilises cascaded optical modulators to achieve either an optical single sideband (OSSB) or double sideband-suppressed carrier (DSB-SC) signal with high sideband suppression. Our analysis and simulation results indicate that the achievable suppression ratio of this configuration is only limited by other system factors such as optical noise and drifting of the operational conditions. The OSSB transmission system performance is assessed experimentally by the transport of 4 WiMax channels modulating a 10 GHz optical upconverted RF carrier as well as for optical frequency doubling and tripling. The 10 GHz and tripled carrier at 30 GHz are dispersion tolerant resulting both in an average relative constellation error (RCE) of -28.7 dB after 40 km of fibre.

  3. Structural and Optical Study of Chemical Bath Deposited Nano-Structured CdS Thin Films

    NASA Astrophysics Data System (ADS)

    Kumar, Suresh; Sharma, Dheeraj; Sharma, Pankaj; Sharma, Vineet; Barman, P. B.; Katyal, S. C.

    2011-12-01

    CdS is commonly used as window layer in polycrystalline solar cells. The paper presents a structural and optical study of CdS nano-structured thin films. High quality CdS thin films are grown on commercial glass by means of chemical bath deposition. It involves an alkaline solution of cadmium salt, a complexant, a chalcogen source and a non-ionic surfactant. The films have been prepared under various process parameters. The chemically deposited films are annealed to estimate its effect on the structural and optical properties of films. These films (as -deposited and annealed) have been characterized by means of XRD, SEM and UV-Visible spectrophotometer. XRD of films show the nano-crystalline nature. The energy gap of films is found to be of direct in nature.

  4. Reflectivity quenching of ESR multilayer polymer film reflector in optically bonded scintillator arrays

    NASA Astrophysics Data System (ADS)

    Loignon-Houle, Francis; Pepin, Catherine M.; Charlebois, Serge A.; Lecomte, Roger

    2017-04-01

    The 3M-ESR multilayer polymer film is a widely used reflector in scintillation detector arrays. As specified in the datasheet and confirmed experimentally by measurements in air, it is highly reflective (> 98 %) over the entire visible spectrum (400-1000 nm) for all angles of incidence. Despite these outstanding characteristics, it was previously found that light crosstalk between pixels in a bonded LYSO scintillator array with ESR reflector can be as high as ∼30-35%. This unexplained light crosstalk motivated further investigation of ESR optical performance. Analytical simulation of a multilayer structure emulating the ESR reflector showed that the film becomes highly transparent to incident light at large angles when surrounded on both sides by materials of refractive index higher than air. Monte Carlo simulations indicate that a considerable fraction (∼25-35%) of scintillation photons are incident at these leaking angles in high aspect ratio LYSO scintillation crystals. The film transparency was investigated experimentally by measuring the scintillation light transmission through the ESR film sandwiched between a scintillation crystal and a photodetector with or without layers of silicone grease. Strong light leakage, up to nearly 30%, was measured through the reflector when coated on both sides with silicone, thus elucidating the major cause of light crosstalk in bonded arrays. The reflector transparency was confirmed experimentally for angles of incidence larger than 60 ° using a custom designed setup allowing illumination of the bonded ESR film at selected grazing angles. The unsuspected ESR film transparency can be beneficial for detector arrays exploiting light sharing schemes, but it is highly detrimental for scintillator arrays designed for individual pixel readout.

  5. Optical pH sensor based on the chemical modification of a porous polymer film

    SciTech Connect

    Jones, T.P.; Porter, M.D.

    1988-03-01

    A new approach to the design and construction of an optical pH sensor has been developed by immobilizing a direct azo dye at a porous cellulosic polymer film. This sensor was fabricated by binding Congo Red to a cellulose acetate film that had previously been subjected to an exhaustive base hydrolysis. Advantageous features of the design include (1) a rapid equilibration time (< 1.3 s), (2) a large dynamic range (> 4 pH units), and (3) ease of fabrication. The rapid response results from the porous structure of the polymeric support, which minimizes barriers to mass transport. The large dynamic range results from both the polyprotic acid-base reactivity of Congo Red and the large optical absorptivities of its various ionic forms. Furthermore, these results indicate that a variety of optical sensors which exhibit a rapid and sensitive response for the analysis of pH can be easily fabricated by immobilizing carefully selected direct dyes at porous polymeric substrates such as hydrolyzed cellulose acetate.

  6. Analysis of long-term internal stress and film structure of SiO2 optical thin films.

    PubMed

    Nishikawa, Toshiyuki; Ono, Hiroi; Murotani, Hiroshi; Iida, Yoshitaka; Okada, Katsuhisa

    2011-03-20

    Recently, the demand for durability of optical thin films, which have long been used, has been growing as the performance of optical components improves. The stress of a film is an important parameter that is related to its adhesion. The electron beam (EB) and ion-assisted deposition (IAD) methods are widely used to fabricate optical thin films. However, there are few reports on long-term internal stress, despite the importance of this issue. Here we discuss the time dependence of the stress of SiO2 optical thin films in terms of optical characteristics in the infrared region. It was found that SiO2 thin films prepared by the EB and IAD methods exhibited compression stress. The Si-OH molecular bond was observed at around 930 cm(-1) in the Fourier transform infrared spectroscopy spectrum of the sample prepared by the EB method, which exhibited a large change in internal stress after an elapsed time. It is considered that this change in bonding was related to the decrease in the stress of the films.

  7. CdS nanofilms: Effect of film thickness on morphology and optical band gap

    NASA Astrophysics Data System (ADS)

    Kumar, Suresh; Kumar, Santosh; Sharma, Pankaj; Sharma, Vineet; Katyal, S. C.

    2012-12-01

    CdS nanofilms of varying thickness (t) deposited by chemical bath deposition technique have been studied for structural changes using x-ray diffractometer (XRD) and transmission electron microscope (TEM). XRD analysis shows polycrystalline nature in deposited films with preferred orientation along (002) reflection plane also confirmed by selected area diffraction pattern of TEM. Uniform and smooth surface morphology observed using field emission scanning electron microscope. The surface topography has been studied using atomic force microscope. The optical constants have been calculated from the analysis of %T and %R spectra in the wavelength range 300 nm-900 nm. CdS nanofilms show a direct transition with red shift. The optical band gap decreases while the refractive index increases with increase in thickness of nanofilms.

  8. State-of-the-art thin film X-ray optics for synchrotrons and FEL sources

    NASA Astrophysics Data System (ADS)

    Hertlein, Frank; Wiesmann, Jörg; Michaelsen, Carsten; Störmer, Michael; Seifert, Andreas

    2007-05-01

    Selected aspects of simulation, preparation and characterization of total reflection and multilayer X-ray optics will be discussed. The best multilayer is found by calculating the optical properties of the coating. Sophisticated improvements in deposition technology allow the precise realization of the specified parameters when manufacturing the X-ray optics. The quality of the shape of the substrate for the optics is measured with the aid of profilometry. X-ray reflectometry measures both film thickness as well as their lateral gradient. Last but not least we will be showing results of the development of carbon coatings as total reflection mirrors for FEL (free electron laser) sources. Over the past years we have developed optimized optics for the XUV range up to 200 eV. First FEL irradiation tests have shown that carbon coatings offer high reflectivity > 95%, high radiation stability, good uniformity in thickness and roughness. An optimized coating of two stripes for different beam energies was produced especially for a tomography beamline, where a Ru/C multilayer was chosen for energies between 10 and 22 keV and a W/Si multilayer for energies between 22 and 45 keV.

  9. Analytical method for determining optical constants and thickness of absorbing films from absorption spectra

    SciTech Connect

    Filippov, V.V.

    1995-05-01

    It is shown that the reflecting power of the air-film interface can be determined from the envelopes of the extremes of interference fringes in the reflection spectrum of the absorbing film. From these data, using the oblique incidence and measurements in two polarizations, the optical constants of the film can be determined without any assumptions about the dispersion and the film thickness can be calculated analytically. 10 refs., 1 tab.

  10. Chemically modified graphene films for high-performance optical NO2 sensors.

    PubMed

    Xing, Fei; Zhang, Shan; Yang, Yong; Jiang, Wenshuai; Liu, Zhibo; Zhu, Siwei; Yuan, Xiaocong

    2016-08-07

    Various graphene-based gas sensors that operate based on the electrical properties of graphene have been developed for accurate detection of gas components. However, electronic graphene-based gas sensors are unsafe under explosive atmospheres and sensitive to electromagnetic interference. Here, a novel optical graphene-based gas sensor for NO2 detection is established based on surface chemical modification of high-temperature-reduced graphene oxide (h-rGO) films with sulfo groups. Sulfo group-modified h-rGO (S-h-rGO) films with a thickness of several nanometers exhibit excellent performance in NO2 detection at room temperature and atmospheric pressure based on the polarization absorption effect of graphene. Initial slope analysis of the S-h-rGO sensor indicates that it has a limit of detection of 0.28 ppm and a response time of 300 s for NO2 gas sensing. Furthermore, the S-h-rGO sensor also possesses the advantages of good linearity, reversibility, selectivity, non-contact operation, low cost and safety. This novel optical gas sensor has the potential to serve as a general platform for the selective detection of a variety of gases with high performance.

  11. Phase-selective vanadium dioxide (VO{sub 2}) nanostructured thin films by pulsed laser deposition

    SciTech Connect

    Masina, B. N. E-mail: slafane@cdta.dz; Lafane, S. E-mail: slafane@cdta.dz; Abdelli-Messaci, S.; Kerdja, T.; Wu, L.; Akande, A. A.; Mwakikunga, B.

    2015-10-28

    Thin films of monoclinic nanostructured vanadium dioxide are notoriously difficult to produce in a selective manner. To date, post-annealing, after pulsed laser deposition (PLD), has been used to revert the crystal phase or to remove impurities, and non-glass substrates have been employed, thus reducing the efficacy of the transparency switching. Here, we overcome these limitations in PLD by optimizing a laser-ablation and deposition process through optical imaging of the laser-induced plasma. We report high quality monoclinic rutile-type vanadium dioxide (VO{sub 2}) (M1) nanoparticles without post-annealing, and on a glass substrate. Our samples demonstrate a reversible metal-to-insulator transition at ∼43 °C, without any doping, paving the way to switchable transparency in optical materials at room temperature.

  12. Polarization-selective optical transmission through a plasmonic metasurface

    SciTech Connect

    Pelzman, Charles; Cho, Sang-Yeon

    2015-06-22

    We present the design, fabrication, and experimental characterization of a nanoslit-based metasurface that offers polarization-selective optical transmission for advanced imaging applications. The metasurface consists of an array of meta-atoms, constructed with two orthogonally coupled subwavelength apertures. Highly enhanced optical transmission was achieved by selective excitation of surface plasmon waves on the metasurface. By rotating the orientation of the linearly polarized incident beam, switching of enhanced optical transmission bands through the metasurface was experimentally demonstrated. This demonstration is a significant step towards developing advanced multispectral imaging devices.

  13. Optical and electrical properties of thin superconducting films

    NASA Astrophysics Data System (ADS)

    Covington, Billy C.; Jing, Feng Chen

    1990-12-01

    Infrared spectroscopic techniques can provide a vital probe of the superconducting energy gap which is one of the most fundamental physical properties of superconductors. Currently, the central questions regarding the optical properties of superconductors are how the energy gap can be measured by infrared techniques and at which frequency the gap exists. An effective infrared spectroscopic method to investigate the superconducting energy gap, Eg, was developed by using the Bomem DA 3.01 Fourier Transformation Spectrophotometer. The reflectivity of a superconducting thin film of YBaCuO deposited on SrTiO3 was measured. A shoulder was observed in the superconducting state reflectance R(sub S) at 480/cm. This gives a value of Eg/kT(sub c) = 7.83, where k is the Boltzmann constant and T(sub c) is the superconducting transition temperature, from which, it is suggested that YBaCuO is a very strong coupling superconductor.

  14. Continuously controlled optical band gap in oxide semiconductor thin films

    DOE PAGES

    Herklotz, Andreas; Rus, Stefania Florina; Ward, Thomas Zac

    2016-02-02

    The optical band gap of the prototypical semiconducting oxide SnO2 is shown to be continuously controlled through single axis lattice expansion of nanometric films induced by low-energy helium implantation. While traditional epitaxy-induced strain results in Poisson driven multidirectional lattice changes shown to only allow discrete increases in bandgap, we find that a downward shift in the band gap can be linearly dictated as a function of out-of-plane lattice expansion. Our experimental observations closely match density functional theory that demonstrates that uniaxial strain provides a fundamentally different effect on the band structure than traditional epitaxy-induced multiaxes strain effects. In conclusion, chargemore » density calculations further support these findings and provide evidence that uniaxial strain can be used to drive orbital hybridization inaccessible with traditional strain engineering techniques.« less

  15. Continuously controlled optical band gap in oxide semiconductor thin films

    SciTech Connect

    Herklotz, Andreas; Rus, Stefania Florina; Ward, Thomas Zac

    2016-02-02

    The optical band gap of the prototypical semiconducting oxide SnO2 is shown to be continuously controlled through single axis lattice expansion of nanometric films induced by low-energy helium implantation. While traditional epitaxy-induced strain results in Poisson driven multidirectional lattice changes shown to only allow discrete increases in bandgap, we find that a downward shift in the band gap can be linearly dictated as a function of out-of-plane lattice expansion. Our experimental observations closely match density functional theory that demonstrates that uniaxial strain provides a fundamentally different effect on the band structure than traditional epitaxy-induced multiaxes strain effects. In conclusion, charge density calculations further support these findings and provide evidence that uniaxial strain can be used to drive orbital hybridization inaccessible with traditional strain engineering techniques.

  16. Neutron diffraction optics of films with noncollinear magnetic depth structures

    NASA Astrophysics Data System (ADS)

    Korneev, Daniel A.; Chernenko, L. P.

    1992-11-01

    A model of a thin film with depth inhomogeneous or noncollinear magnetization is used to describe its neutron-optical, diffraction, and polarization properties. A quantum mechanical method of calculation is developed based on a numerical solution of the Pauli equation for a neutron in inhomogeneous matter with boundary conditions. This solution permits the uniform calculation of intensities and the polarization vector of the scattered beam over a wide range of conditions from specular reflection to neutron diffraction. The method is applied to certain model structures. Examples of its application to model structures (ferromagnetic spirals, long- period soliton) are given and the calculation can be programmed for a personal computer, taking a few seconds for each value of the incident neutron wave vector.

  17. Photonic crystals and optical mode engineering for thin film photovoltaics.

    PubMed

    Gomard, Guillaume; Peretti, Romain; Drouard, Emmanuel; Meng, Xianqin; Seassal, Christian

    2013-05-06

    In this paper, we present the design, analysis, and experimental results on the integration of 2D photonic crystals in thin film photovoltaic solar cells based on hydrogenated amorphous silicon. We introduce an analytical approach based on time domain coupled mode theory to investigate the impact of the photon lifetime and anisotropy of the optical resonances on the absorption efficiency. Specific design rules are derived from this analysis. We also show that, due to the specific properties of the photonic crystal resonances, the angular acceptance of such solar cells is particularly high. Rigorous Coupled Wave Analysis simulations show that the absorption in the a-Si:H active layers, integrated from 300 to 750 nm, is only decreased from 65.7% to 60% while the incidence angle is increased from 0 to 55°. Experimental results confirm the stability of the incident light absorption in the patterned stack, for angles of incidence up to 50°.

  18. Model of a thin film optical fiber fluorosensor

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O.; Rogowski, Robert S.

    1991-01-01

    The efficiency of core-light injection from sources in the cladding of an optical fiber is modeled analytically by means of the exact field solution of a step-profile fiber. The analysis is based on the techniques by Marcuse (1988) in which the sources are treated as infinitesimal electric currents with random phase and orientation that excite radiation fields and bound modes. Expressions are developed based on an infinite cladding approximation which yield the power efficiency for a fiber coated with fluorescent sources in the core/cladding interface. Marcuse's results are confirmed for the case of a weakly guiding cylindrical fiber with fluorescent sources uniformly distributed in the cladding, and the power efficiency is shown to be practically constant for variable wavelengths and core radii. The most efficient fibers have the thin film located at the core/cladding boundary, and fibers with larger differences in the indices of refraction are shown to be the most efficient.

  19. Model of a thin film optical fiber fluorosensor

    NASA Astrophysics Data System (ADS)

    Egalon, Claudio O.; Rogowski, Robert S.

    1991-03-01

    The efficiency of core-light injection from sources in the cladding of an optical fiber is modeled analytically by means of the exact field solution of a step-profile fiber. The analysis is based on the techniques by Marcuse (1988) in which the sources are treated as infinitesimal electric currents with random phase and orientation that excite radiation fields and bound modes. Expressions are developed based on an infinite cladding approximation which yield the power efficiency for a fiber coated with fluorescent sources in the core/cladding interface. Marcuse's results are confirmed for the case of a weakly guiding cylindrical fiber with fluorescent sources uniformly distributed in the cladding, and the power efficiency is shown to be practically constant for variable wavelengths and core radii. The most efficient fibers have the thin film located at the core/cladding boundary, and fibers with larger differences in the indices of refraction are shown to be the most efficient.

  20. Optical and electrical properties of thin superconducting films

    NASA Technical Reports Server (NTRS)

    Covington, Billy C.; Jing, Feng Chen

    1990-01-01

    Infrared spectroscopic techniques can provide a vital probe of the superconducting energy gap which is one of the most fundamental physical properties of superconductors. Currently, the central questions regarding the optical properties of superconductors are how the energy gap can be measured by infrared techniques and at which frequency the gap exists. An effective infrared spectroscopic method to investigate the superconducting energy gap, Eg, was developed by using the Bomem DA 3.01 Fourier Transformation Spectrophotometer. The reflectivity of a superconducting thin film of YBaCuO deposited on SrTiO3 was measured. A shoulder was observed in the superconducting state reflectance R(sub S) at 480/cm. This gives a value of Eg/kT(sub c) = 7.83, where k is the Boltzmann constant and T(sub c) is the superconducting transition temperature, from which, it is suggested that YBaCuO is a very strong coupling superconductor.

  1. High Energy Effects on Thermoelectric and Optical Properties of Si/Si+Sb Nanolayered Thin Films

    DTIC Science & Technology

    2013-04-01

    REPORT High Energy Effects on Thermoelectric and Optical Properties of Si/Si+Sb Nanolayered Thin Films 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: We...Energy Effects on Thermoelectric and Optical Properties of Si/Si+Sb Nanolayered Thin Films Report Title ABSTRACT We have prepared thermoelectric...the cross plane Seebeck coefficient and increase the cross plane electrical conductivity to increase the figure of merit. Some optical

  2. Optical waveguide spectrometer based on thin-film glass plates.

    PubMed

    Qi, Zhi-Mei; Matsuda, Naoki; Yoshida, Takamitsu; Asano, Hajime; Takatsu, Akiko; Kato, Kenji

    2002-11-15

    Commercially available thin-film glass plates have been successfully used for optical waveguide spectroscopy of chemical and biological films adsorbed upon the plates' surfaces. A 50-mum -thick glass plate was placed in contact with two parallel strips of silicone rubber supported on a slide glass. The plate area between the rubber strips served as the waveguiding region, eliminating the negative effect of the substrate on absorbance sensitivity. We coupled white light into the waveguide by focusing the light from a xenon lamp onto one end of a glass fiber and then inserting the other end into a glycerol drop overlaid upon the plate's surface. With a CCD detector, light at wavelengths as short as 360 nm was found to transmit out of the plate's end face. The propagation loss of the waveguide was measured to be

  3. Experimental design approach for deposition optimization of RF sputtered chalcogenide thin films devoted to environmental optical sensors.

    PubMed

    Baudet, E; Sergent, M; Němec, P; Cardinaud, C; Rinnert, E; Michel, K; Jouany, L; Bureau, B; Nazabal, V

    2017-06-14

    The development of the optical bio-chemical sensing technology is an extremely important scientific and technological issue for diagnosis and monitoring of diseases, control of industrial processes, environmental detection of air and water pollutants. Owing to their distinctive features, chalcogenide amorphous thin films represent a keystone in the manufacture of middle infrared integrated optical devices for a sensitive detection of biological or environmental variations. Since the chalcogenide thin films characteristics, i.e. stoichiometric conformity, structure, roughness or optical properties can be affected by the growth process, the choice and control of the deposition method is crucial. An approach based on the experimental design is undoubtedly a way to be explored allowing fast optimization of chalcogenide film deposition by means of radio frequency sputtering process. Argon (Ar) pressure, working power and deposition time were selected as potentially the most influential factors among all possible. The experimental design analysis confirms the great influence of the Ar pressure on studied responses: chemical composition, refractive index in near-IR (1.55 µm) and middle infrared (6.3 and 7.7 µm), band-gap energy, deposition rate and surface roughness. Depending on the intended application and therefore desired thin film characteristics, mappings of the experimental design meaningfully help to select suitable deposition parameters.

  4. Effects of cryogenic contaminants on optical surfaces: calculations of reflectance and transmittance (CALCRT) thin-film reflectance/transmittance model

    NASA Astrophysics Data System (ADS)

    Bertrand, William T.; Wood, Bob E.; Palmer, Kent F.

    1994-10-01

    Contamination of infrared sensor systems is an area of concern to spacecraft operators and designers. This paper describes the CALCRT mathematical model which can be used for calculating the reflectance and transmittance effects of thin contaminant films on optical surfaces. It uses an optical property data base that contains the cryogenic optical properties (refractive and absorptive indices) for satellite material outgassing products, atmospheric gases, propellants, and bipropellant plume products. The bipropellant plume data were obtained during firings of a 5 lb. thrust monomethylhydrazine/nitrogen tetroxide engine. Contaminant effects can be calculated as a function of substrate refractive index, incidence angle, film thickness, film materials, wavelength, and wavenumber. The model has been modified to treat the case when the condensate contains a mixture of molecular species or when a deposit on a surface consists of a `stack' of uniform layers, each of which has a distinct material composition. Computed transmittance spectra of selected films of mixtures are compared with transmittance spectra calculated with measured optical constants of the mixture.

  5. Selective-resputtering-induced perpendicular magnetic anisotropy in amorphous TbFe films.

    PubMed

    Harris, V G; Pokhil, T

    2001-08-06

    Perpendicular magnetic anisotropy energy in rf magnetron sputtered amorphous TbFe films is measured to increase exponentially with pair-order anisotropy induced by the selective resputtering of surface adatoms during film growth.

  6. Study of structural and optical properties of chemically synthesized nanostructured cadmium zinc sulphide films for band gap tunability

    NASA Astrophysics Data System (ADS)

    Mochahari, P. K.; Sarma, K. C.

    2016-01-01

    Nanostructured cadmium zinc sulphide films have been deposited onto cleaned glass substrates by chemical bath deposition method at room temperature using polyvinyl alcohol as capping agent. X-ray diffraction analysis confirms the formation of cubic-phase cadmium zinc sulphide films. Crystallite size obtained from the calculation of Scherrer's formula and Williamson-Hall plot as well as size-strain plot is found to decrease with the increase in zinc concentration. The films have very high dislocation density of the order of 1016 m-2, whereas the strain is of the order of 10-3. Scanning electron microscopic image reveals that the particles are agglomerated to form nanoclusters and energy-dispersive X-ray analysis confirms that films are composed of cadmium, zinc and sulphur. High-resolution transmission electron microscopic image reveals that the shape of the particles is nearly spherical, uniformly distributed. Selected-area electron diffraction pattern supports the formation of cubic phase of the film. Optical absorption peaks of the films shift towards lower wavelength side and their optical band gap increases with the increase in zinc concentration. The increase in zinc concentration enhances the photoluminescence emission intensity, whose emission is in the green region of visible spectrum.

  7. Ion irradiation as a tool for modifying the surface and optical properties of plasma polymerised thin films

    NASA Astrophysics Data System (ADS)

    Grant, Daniel S.; Bazaka, Kateryna; Siegele, Rainer; Holt, Stephen A.; Jacob, Mohan V.

    2015-10-01

    Radio frequency (R.F.) glow discharge polyterpenol thin films were prepared on silicon wafers and irradiated with I10+ ions to fluences of 1 × 1010 and 1 × 1012 ions/cm2. Post-irradiation characterisation of these films indicated the development of well-defined nano-scale ion entry tracks, highlighting prospective applications for ion irradiated polyterpenol thin films in a variety of membrane and nanotube-fabrication functions. Optical characterisation showed the films to be optically transparent within the visible spectrum and revealed an ability to selectively control the thin film refractive index as a function of fluence. This indicates that ion irradiation processing may be employed to produce plasma-polymer waveguides to accommodate a variety of wavelengths. XRR probing of the substrate-thin film interface revealed interfacial roughness values comparable to those obtained for the uncoated substrate's surface (i.e., both on the order of 5 Å), indicating minimal substrate etching during the plasma deposition process.

  8. Chemical gas sensor application of open-pore mesoporous thin films based on integrated optical polarimetric interferometry.

    PubMed

    Qi, Zhi-Mei; Honma, Itaru; Zhou, Haoshen

    2006-02-15

    Chemical gas sensors that employ integrated optical polarimetric interferometry were fabricated by the sol-gel synthesis of transparent mesoporous thin films of TiO2-P2O5 nanocomposite on tapered layers of TiO2 sputtered on tin-diffused glass waveguides. Atomic force microscopy images of the mesoporous thin film clearly show the open pore mouths on the film surface that favor rapid diffusion and adsorption of gas-phase analytes within the entire film. Adsorption of gas and vapor induces changes (Deltan) in the refractive index of the mesoporous thin film that lead to shifts in the phase difference between the fundamental transverse electric and magnetic modes simultaneously excited in the glass waveguide via single-beam incidence. Upon exposure to NH3 gas at concentrations as low as 100 ppb in dry air at room temperature, the sensor exhibits a reversible change in the phase difference with the response and recovery times of less than 60 and 90 s, respectively. It is unexpected that the sensor is unresponsive to either NO2 or C6H6 vapor, leading to a somewhat selective sensitivity to NH3. Determination of Deltan was carried out with a combination of the experimental results and the theoretical calculations. The sensor design represents a novel, effective, and easily accessible approach to mesoporous thin-film-based integrated optical chemical sensors.

  9. Studies of Optical Wave Front Conjugation and Imaging Properties of Nematic Liquid Crystal Films

    DTIC Science & Technology

    1988-06-30

    processes was also demonstrated. The capability of optical four wave mixing to generate amplified reflection and self- oscillation in nematic liquid crystal...via real time optical wave mixing process was also demonstrated. The capability of optical four wave mixing to generate amplified reflection and self...the special nonlinear optical properties of liquid crystal films for optical wave front conjugation and in related four -wave mixing processes. The

  10. Depth selective acousto-optic flow measurement

    PubMed Central

    Tsalach, Adi; Schiffer, Zeev; Ratner, Eliahu; Breskin, Ilan; Zeitak, Reuven; Shechter, Revital; Balberg, Michal

    2015-01-01

    Optical based methods for non-invasive measurement of regional blood flow tend to incorrectly assess cerebral blood flow, due to contribution of extra-cerebral tissues to the obtained signal. We demonstrate that spectral analysis of phase-coded light signals, tagged by specific ultrasound patterns, enables differentiation of flow patterns at different depths. Validation of the model is conducted by Monte Carlo simulation. In-vitro experiments demonstrate good agreement with the simulations' results and provide a solid validation to depth discrimination ability. These results suggest that signal contamination originating from extra-cerebral tissue may be eliminated using spectral analysis of ultrasonically tagged light. PMID:26713201

  11. Optical and scratch resistant properties of diamondlike carbon films deposited with single and dual ion beams

    NASA Technical Reports Server (NTRS)

    Kussmaul, Michael T.; Bogdanski, Michael S.; Banks, Bruce A.; Mirtich, Michael J.

    1993-01-01

    Amorphous diamondlike carbon (DLC) films were deposited using both single and dual ion beam techniques utilizing filament and hollow cathode ion sources. Continuous DLC films up to 3000 A thick were deposited on fused quartz plates. Ion beam process parameters were varied in an effort to create hard, clear films. Total DLC film absorption over visible wavelengths was obtained using a Perkin-Elmer spectrophotometer. An ellipsometer, with an Ar-He laser (wavelength 6328 A) was used to determine index of refraction for the DLC films. Scratch resistance and frictional and adherence properties were determined for select films. Applications for these films range from military to the ophthalmic industries.

  12. Optical and Scratch Resistant Properties of Diamondlike Carbon Films Deposited with Single and Dual Ion Beams

    NASA Technical Reports Server (NTRS)

    Kussmaul, Michael T.; Bogdanski, Michael S.; Banks, Bruce A.; Mirtich, Michael J.

    1993-01-01

    Amorphous diamond-like carbon (DLC) films were deposited using both single and dual ion beam techniques utilizing filament and hollow cathode ion sources. Continuous DLC films up to 3000 A thick were deposited on fused quartz plates. Ion beam process parameters were varied in an effort to create hard, clear films. Total DLC film absorption over visible wavelengths was obtained using a Perkin-Elmer spectrophotometer. An ellipsometer, with an Ar-He laser (wavelength 6328 A) was used to determine index of refraction for the DLC films. Scratch resistance, frictional, and adherence properties were determined for select films. Applications for these films range from military to the ophthalmic industries.

  13. Thermal annealing induced structural and optical properties of Se72Te25In3 thin films

    NASA Astrophysics Data System (ADS)

    Pathak, H. P.; Shukla, Nitesh; Kumar, Vipin; Dwivedi, D. K.

    2016-05-01

    Thin films of a- Se72Te25In3 were prepared by vacuum evaporation technique in a base pressure of 10-6 Torr on to well cleaned glass substrate. a-Se72Te25In3 thin films were annealed at different temperatures below their crystallization temperatures for 2h. The structural analysis of the films has been investigated using X-ray diffraction technique. The optical absorption spectra of these films were measured in the wavelength range 400-1100 nm in order to derive the absorption coefficient of these films. The optical band gap of as prepared and annealed films as a function of photon energy has been studied. It has been found that the optical band gap decreases with increasing annealing temperatures in the present system.

  14. A quantum size effect in infrared optical response of aliminum thin films

    NASA Astrophysics Data System (ADS)

    Xiao, Mufei; Villagómez, Ricardo

    1998-03-01

    We present a quantum mechanical calculation for diamagnetic optical response of metallic thin films. The study shows that in the optical response of the thin films, such as the reflectance, there exists an oscillatory dependence on the film thickness when the film contents less than about 100 monolayers, and the period of the oscillation corresponds to one or few monolayers. We show that the oscillation can be attributed to the intraband fluctuations of the valence electrons at discrete energy states as well as at continuum energy states. For comparison, we present some experimental results for Aluminum thin films of thickness 5 ~112ÅInfrared (λ=9.2μ m) optical reflectance of the films was measured, which demonstrates experimentally the predicted oscillating fine structures.

  15. Optical waveguide BTX gas sensor based on polyacrylate resin thin film.

    PubMed

    Kadir, Razak; Yimit, Abliz; Ablat, Hayrensa; Mahmut, Mamtimin; Itoh, Kiminori

    2009-07-01

    An optical sensor sensitive to BTX has been developed by spin coating a thin film of polyacrylate resin onto a tin- diffused glass optical waveguide. A pair of prism coupler was employed for optical coupling matched with diiodomethane (CH2l2). The guided wave transmits in waveguide layer and passes through the film as an evanescent wave. Polyacrylate film has a strong capacity of absorbing oil gases. The film is stable in N2 but benzene exposure at room temperature can result in rapid and reversible changes of transmittance (7) and refractive index (n1) of this film. It has been demonstrated that the sensor containing a 10 mm boardand about a hundred nanometers thick resin film can detect lower than 8 ppm BTX.

  16. Optical Sensors Based on Single Arm Thin Film Waveguide Interferometer

    NASA Technical Reports Server (NTRS)

    Sarkisov, S. S.; Diggs, D.; Curley, M.; Adamovsky, Grigory (Technical Monitor)

    2001-01-01

    Single-arm double-mode double-order optical waveguide interferometer utilizes interference between two propagating modes of different orders. Sensing effect results from the change in propagation conditions of the modes caused by the environment. The waveguide is made as an open asymmetric slab structure containing a dye-doped polymer film onto a fused quartz substrate. It is more sensitive to the change of environment than its conventional polarimetric analog using orthogonal modes (TE and TM) of the same order. The sensor still preserves the option of operating in polarimetric regime using a variety of mode combinations such as TE(sub 0)/TM(sub 0) (conventional), TE(sub 0)/TM(sub 1), TE(sub 1)/TM(sub 0), or TE(sub 1)/TM(sub 1) but can also work in nonpolarimetric regime using combinations TE(sub 0)/TM(sub 1) or TE(sub 0)/TM(sub 1). Utilization of different mode combinations simultaneously makes the device more versatile. Application of the sensor to gas sensing is based on doping polymer film with an organic indicator dye sensitive to a particular gas. Change of optical absorption spectrum of the dye caused by the gaseous pollutant results change of the reactive index of the dye-doped polymer film that can be detected by the sensor. As an indicator dyes, we utilize Bromocresol Purple doped into polymer poly(methyl) methacrylate, which shows a reversible growth of the absorption peak neat 600 nm after exposure to wet ammonia. We have built a breadboard prototype of the sensor with He-Ne laser as a light source and with a single mode fiber input and a multimode fiber output. The prototype showed sensitivity to temperature change of the order of 2 C per one full oscillation of the signal. The sensitivity of the sensor to the presence of wet ammonia is 200 ppm per one full oscillation of the signal. The further improvements include switching to a longer wavelength laser source (750-nm semiconductor laser), substitution of poly(methyl) methacrylate with hydrophilic

  17. Optical Sensors Based on Single Arm Thin Film Waveguide Interferometer

    NASA Technical Reports Server (NTRS)

    Sarkisov, S. S.; Diggs, D.; Curley, M.; Adamovsky, Grigory (Technical Monitor)

    2001-01-01

    Single-arm double-mode double-order optical waveguide interferometer utilizes interference between two propagating modes of different orders. Sensing effect results from the change in propagation conditions of the modes caused by the environment. The waveguide is made as an open asymmetric slab structure containing a dye-doped polymer film onto a fused quartz substrate. It is more sensitive to the change of environment than its conventional polarimetric analog using orthogonal modes (TE and TM) of the same order. The sensor still preserves the option of operating in polarimetric regime using a variety of mode combinations such as TE(sub 0)/TM(sub 0) (conventional), TE(sub 0)/TM(sub 1), TE(sub 1)/TM(sub 0), or TE(sub 1)/TM(sub 1) but can also work in nonpolarimetric regime using combinations TE(sub 0)/TM(sub 1) or TE(sub 0)/TM(sub 1). Utilization of different mode combinations simultaneously makes the device more versatile. Application of the sensor to gas sensing is based on doping polymer film with an organic indicator dye sensitive to a particular gas. Change of optical absorption spectrum of the dye caused by the gaseous pollutant results change of the reactive index of the dye-doped polymer film that can be detected by the sensor. As an indicator dyes, we utilize Bromocresol Purple doped into polymer poly(methyl) methacrylate, which shows a reversible growth of the absorption peak neat 600 nm after exposure to wet ammonia. We have built a breadboard prototype of the sensor with He-Ne laser as a light source and with a single mode fiber input and a multimode fiber output. The prototype showed sensitivity to temperature change of the order of 2 C per one full oscillation of the signal. The sensitivity of the sensor to the presence of wet ammonia is 200 ppm per one full oscillation of the signal. The further improvements include switching to a longer wavelength laser source (750-nm semiconductor laser), substitution of poly(methyl) methacrylate with hydrophilic

  18. Optical properties of Al-CdO nano-clusters thin films

    NASA Astrophysics Data System (ADS)

    Yahia, I. S.; Salem, G. F.; Abd El-sadek, M. S.; Yakuphanoglu, F.

    2013-12-01

    The aluminum doped cadmium oxide (CdO:Al) thin films were grown onto glass substrates by sol-gel spin-coating method. The structural properties of undoped and Al-doped CdO thin films were studied by atomic force microscopy. AFM results reveal that the studied CdO films were formed from the nano-clusters. The optical transmittance of undoped and Al-doped CdO is decreased with increasing Al contents. The optical band gaps of the CdO films were varied from 2.54 eV to 2.32 eV with increasing Al dopants. The width of localized states in the optical band gap of the films is increased with increasing Al content. The improvement of the optical constant of Al-doped CdO has potential applications as transparent conducting oxide for different optoelectronic device applications.

  19. Transparent thin-film characterization by using differential optical sectioning interference microscopy.

    PubMed

    Wang, Chun-Chieh; Lin, Jiunn-Yuan; Jian, Hung-Jhang; Lee, Chau-Hwang

    2007-10-20

    We propose an optical thin-film characterization technique, differential optical sectioning interference microscopy (DOSIM), for simultaneously measuring the refractive indices and thicknesses of transparent thin films with submicrometer lateral resolution. DOSIM obtains the depth and optical phase information of a thin film by using a dual-scan concept in differential optical sectioning microscopy combined with the Fabry-Perot interferometric effect and allows the solution of refractive index and thickness without the 2pi phase-wrapping ambiguity. Because DOSIM uses a microscope objective as the probe, its lateral resolution achieves the diffraction limit. As a demonstration, we measure the refractive indices and thicknesses of SiO2 thin films grown on Si substrate and indium-tin-oxide thin films grown on a glass substrate. We also compare the measurement results of DOSIM with those of a conventional ellipsometer and an atomic force microscope.

  20. Prism coupling technique investigation of elasto-optical properties of thin polymer films

    NASA Astrophysics Data System (ADS)

    Ay, Feridun; Kocabas, Askin; Kocabas, Coskun; Aydinli, Atilla; Agan, Sedat

    2004-12-01

    The use of thin polymer films in optical planar integrated optical circuits is rapidly increasing. Much interest, therefore, has been devoted to characterizing the optical and mechanical properties of thin polymer films. This study focuses on measuring the elasto-optical properties of three different polymers; polystyrene, polymethyl-methacrylate, and benzocyclobutane. The out-of-plane elastic modulus, refractive index, film thickness, and birefringence of thin polymer films were determined by means of the prism coupling technique. The effect of the applied stress on the refractive index and birefringence of the films was investigated. Three-dimensional finite element method analysis was used so as to obtain the principal stresses for each polymer system, and combining them with the stress dependent refractive index measurements, the elasto-optic coefficients of the polymer films were determined. It was found that the applied stress in the out-of-plane direction of the thin films investigated leads to negative elasto-optic coefficients, as observed for all the three thin polymer films.

  1. Magnetic, optical and structural characterization of ZnO:Co; ZnO:Fe thin films

    NASA Astrophysics Data System (ADS)

    Ćakıcı, Tuba; Sarıtaş, Sevda; Muǧlu, Günay Merhan; Kundakçı, Mutlu; Yildirim, Muhammet

    2017-04-01

    Co-doped ZnO and Fe-doped ZnO diluted magnetic semiconductor films were prepared on glass substrates by chemical spray pyrolysis (CSP) method. Synthesized ZnO:Co and ZnO:Fe thin films by CSP method were compared to thin film properties. Optical analysis of the synthesized thin films was examined by spectral absorption and transmittance measurements using UV-Vis double beam spectrophotometer technique and Photoluminescence (PL) spectroscopy. Structural characterizations of the thin films were examined by using X-ray diffraction (XRD), Raman Analysis, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) techniques, respectively. Magnetic properties of the films investigated by Vibrating sample magnetometer (VSM) measurements and magnetization measurements of thin films were compared.VSM measurements of ZnO:Co and ZnO:Fe thin films showed that ferromagnetic behavior for each thin films.

  2. Selective detection of antibodies in microstructured polymer optical fibers.

    PubMed

    Jensen, Jesper; Hoiby, Poul; Emiliyanov, Grigoriy; Bang, Ole; Pedersen, Lars; Bjarklev, Anders

    2005-07-25

    We demonstrate selective detection of fluorophore labeled antibodies from minute samples probed by a sensor layer of complementary biomolecules immobilized inside the air holes of microstructured Polymer Optical Fiber (mPOF). The fiber core is defined by a ring of 6 air holes and a simple procedure was applied to selectively capture either alpha-streptavidin or alpha-CRP antibodies inside these air holes. A sensitive and easy-to-use fluorescence method was used for the optical detection. Our results show that mPOF based biosensors can provide reliable and selective antibody detection in ultra small sample volumes.

  3. Thin-film fiber optic hydrogen and temperature sensor system

    DOEpatents

    Nave, Stanley E.

    1998-01-01

    The invention discloses a sensor probe device for monitoring of hydrogen gas concentrations and temperatures by the same sensor probe. The sensor probe is constructed using thin-film deposition methods for the placement of a multitude of layers of materials sensitive to hydrogen concentrations and temperature on the end of a light transparent lens located within the sensor probe. The end of the lens within the sensor probe contains a lens containing a layer of hydrogen permeable material which excludes other reactive gases, a layer of reflective metal material that forms a metal hydride upon absorbing hydrogen, and a layer of semi-conducting solid that is transparent above a temperature dependent minimum wavelength for temperature detection. The three layers of materials are located at the distal end of the lens located within the sensor probe. The lens focuses light generated by broad-band light generator and connected by fiber-optics to the sensor probe, onto a reflective metal material layer, which passes through the semi-conducting solid layer, onto two optical fibers located at the base of the sensor probe. The reflected light is transmitted over fiberoptic cables to a spectrometer and system controller. The absence of electrical signals and electrical wires in the sensor probe provides for an elimination of the potential for spark sources when monitoring in hydrogen rich environments, and provides a sensor free from electrical interferences.

  4. Optical meta-films of alumina nanowire arrays for solar evaporation and optoelectronic devices (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kim, Kyoungsik; Bae, Kyuyoung; Kang, Gumin; Baek, Seunghwa

    2017-05-01

    Nanowires with metallic or dielectric materials have received considerable interest in many research fields for optical and optoelectronic devices. Metal nanowires have been extensively studied due to the high optical and electrical properties and dielectric nanowires are also investigated owing to the multiple scattering of light. In this research, we report optical meta-films of alumina nanowire arrays with nanometer scale diameters by fabrication method of self-aggregate process. The aluminum oxide nanowires are transparent from ultraviolet to near infrared wavelength regions and array structures have strong diffusive light scattering. We integrate those optical properties from the material and structure, and produce efficient an optical haze meta-film which has high transparency and transmission haze at the same time. The film enhances efficiencies of optical devices by applying on complete products, such as organic solar cells and LEDs, because of an expanded optical path length and light trapping in active layers maintaining high transparency. On the other hands, the meta-film also produces solar steam by sputtering metal on the aluminum oxide nanowire arrays. The nanowire array film with metal coating exhibits ultrabroadband light absorption from ultraviolet to mid-infrared range which is caused by nanofocusing of plasmons. The meta-film efficiently produces water steam under the solar light by metal-coated alumina arrays which have high light-to-heat conversion efficiency. The design, fabrication, and evaluation of our light management platforms and their applications of the meta-films will be introduced.

  5. Nonlinear optical properties of nanometer-size silver composite azobenzene containing polydiacetylene film

    NASA Astrophysics Data System (ADS)

    Chen, Xin; Tao, Jun; Zou, Gang; Zhang, Qijin; Wang, Pei

    2010-07-01

    Diacetylene monomer containing p-nitrophenyl azobenzene moiety (NADA) was synthesized. Silver nanoparticles with different concentrations were adulterated in the above polymerized NADA (PNADA) films and the third-order nonlinear optical properties were investigated in detail. UV-vis spectra and transmission electron microscopy were used to confirm the formation of PNADA/Ag nanocomposite films. The silver nanoparticles (average size of 10 nm) were well dispersed in the polymer films. The value of the nonlinear refractive index n 2 for PNADA films (8.48×10-15 cm2/W) was much higher than that of pure polydiacetylene films. Further, the introduction of silver nanoparticles into the PNADA polymer films led to the further enhancement of nonlinear optical properties. The maximum value of n 2 for PNADA/Ag nanocomposite films could be 11.6×10-15 cm2/W. This enhancement should be ascribed to the surface plasmon resonance of silver nanoparticles.

  6. Optical band gap study of a-Se and Se-Sb thin films

    NASA Astrophysics Data System (ADS)

    Kaur, Ramandeep; Singh, Palwinder; Thakur, Anup

    2016-05-01

    Amorphous selenium (a-Se) and a-Se95Sb5 alloy were prepared using melt quenching technique. X-ray diffraction (XRD) pattern confirmed the amorphous nature of the prepared samples. Composition of the prepared samples has been determined using Energy dispersive X-ray fluorescence (EDXRF) technique. Differential thermal analysis (DTA) confirmed the glassy nature of the prepared samples. Thin films of the prepared samples were deposited on glass substrate using thermal evaporation method. Amorphous nature of the deposited films was confirmed using XRD. Optical properties of these films were obtained from the UV-VIS transmission spectra, at normal incidence, over 200-1100 nm spectral range. The optical absorption edge was described by using the model given by the Tauc. Optical band gap of the deposited films was calculated using Tauc plot. Optical characterization showed that average transmission and optical band gap decreased with the addition of antinomy.

  7. Optical properties of γ-irradiated Bombyx mori silk fibroin films

    NASA Astrophysics Data System (ADS)

    Madhukumar, R.; Asha, S.; Lakshmeesha Rao, B.; Sarojini, B. K.; Byrappa, K.; Wang, Youjiang; Sangappa, Y.

    2015-11-01

    In the present work the Bombyx mori silk fibroin (SF) films were prepared by the solution casting method and effects of γ-irradiation on the optical properties and optical constants of the films have been studied by using Ultra Violet-Visible (UV-Vis) spectrophotometer. The recorded UV-Vis absorption and transmission spectra have been used to determine the optical band gap (Eg), refractive index (n), extinction coefficient (k), optical conductivity (σopt) and dielectric constants (ε*) of virgin and γ-irradiated films. Reduction in optical band gap and increase in refractive index with increasing radiation dosage were observed. It is also found that there is an increase in dielectric constants with increasing photon energy. The obtained results reveal that the refractive index of the SF films may be efficiently changed by γ-irradiation.

  8. Optical band gap study of a-Se and Se-Sb thin films

    SciTech Connect

    Kaur, Ramandeep; Singh, Palwinder; Thakur, Anup

    2016-05-06

    Amorphous selenium (a-Se) and a-Se{sub 95}Sb{sub 5} alloy were prepared using melt quenching technique. X-ray diffraction (XRD) pattern confirmed the amorphous nature of the prepared samples. Composition of the prepared samples has been determined using Energy dispersive X-ray fluorescence (EDXRF) technique. Differential thermal analysis (DTA) confirmed the glassy nature of the prepared samples. Thin films of the prepared samples were deposited on glass substrate using thermal evaporation method. Amorphous nature of the deposited films was confirmed using XRD. Optical properties of these films were obtained from the UV-VIS transmission spectra, at normal incidence, over 200-1100 nm spectral range. The optical absorption edge was described by using the model given by the Tauc. Optical band gap of the deposited films was calculated using Tauc plot. Optical characterization showed that average transmission and optical band gap decreased with the addition of antinomy.

  9. Optically selective, acoustically resonant gas detecting transducer

    NASA Technical Reports Server (NTRS)

    Dimeff, J. (Inventor)

    1977-01-01

    A gas analyzer is disclosed which responds to the resonant absorption or emission spectrum of a specific gas by producing an acoustic resonance in a chamber containing a sample of that gas, and which measures the amount of that emission or absorption by measuring the strength of that acoustic resonance, e.g., the maximum periodic pressure, velocity or density achieved. In the preferred embodiment, a light beam is modulated periodically at the acoustical resonance frequency of a closed chamber which contains an optically dense sample of the gas of interest. Periodic heating of the absorbing gas by the light beam causes a cyclic expansion, movement, and pressure within the gas. An amplitude is reached where the increased losses were the cyclic radiation energy received. A transducing system is inclined for converting the pressure variations of the resonant gas into electronic readout signals.

  10. Effect of oxygen flow on the structure and optical properties of the Gd2O3 optical films

    NASA Astrophysics Data System (ADS)

    Wang, Siyu; Ma, Ping; Pu, Yunti; Qiao, Zhao; Zhang, Mingxiao; Lu, Zhongwen; Peng, Dongxu

    2016-10-01

    Gd2O3 thin films were deposited by Ion-beam sputtering (IBS) under the oxygen flow of 0 sccm~30 sccm. The structure and optical properties of the Gd2O3 optical films were investigated by Lambdar950 spectrophotometer, laser calorimetry and atomic force microscopy (AFM). When oxygen flow was less than 10 sccm, with the increase of oxygen flow, the transmittance of the films increased, at the same time absorptance and the surface roughness of the films decreased. While the flow was more than 10 sccm, with the increase of the flow rate, the surface roughness of the films increased, but the transmittance and absorptance did not show any apparent change. The results show that both the structure and optical properties are closely related to the flow of oxygen. XPS measurements demonstrated that when the oxygen flow increase from 0 sccm to 10 sccm, the defect oxygen decreases. But when the oxygen flow increase from 10 sccm to 30 sccm, the defect oxygen increase. The XPS spectra show that when the oxygen flow was 10 sccm, the defect oxygen was the least. Thus when the oxygen flow was 10 sccm, the structure and optical properties of the Gd2O3 optical films were the best.

  11. Nanofibers and thin films as a selective membrane for sensors and microTAS

    NASA Astrophysics Data System (ADS)

    da Silva, A. N. R.; da Silva, M. L. P.; Fachini, E. R.

    2013-03-01

    A composite material of PAN (polyacrylonitrile), starch granules and dimethylformamide as solvent was used as a selective membrane for volatile organic compounds (VOCs) in gaseous phase. This composite was produced as a thin film obtained by spin-casting and as a fiber mat produced by electrospinning. The fiber mat was tested for adsorption of VOCs and water. Characterization used microscopy (electron scanning and optical) in order to evaluate the fiber morphology and the starch incorporation in the PAN matrix. Infrared spectroscopy was intended to determine the starch presence. Relative viscosity of the starch/PAN suspensions was measured in order to provide a model of composite fiber formation. Quartz crystal microbalance experiments determined VOCs and water adsorption. Fibers incorporated the starch granules, making the composite sensible to water; but VOCs were not detected. Therefore, the composite was found to be a good choice as selective barrier on sensors or microTAS protection purposes.

  12. Effect of substrate temperature on structural, morphological, optical and electrical properties of IGZO thin films

    NASA Astrophysics Data System (ADS)

    Jayaraman, Vinoth Kumar; Álvarez, Arturo Maldonado; Olvera Amador, María de la luz

    2017-02-01

    Indium and gallium co-doped zinc oxide (IGZO) thin films were deposited on glass substrates by ultrasonic spray pyrolysis. Physical properties such as structural, morphological, optical and electrical properties were examined on IGZO thin films with respect to the changes in the substrate temperature (425, 450 and 475 °C). Structural results showed that IGZO films were crystalline and presented hexagonal wurtzite structure. Morphological studies proved that the substrate temperature changed the sizes of hexagonal nanostructures of IGZO. Optical transmittance in the UV-vis region and electrical measurements confirmed that IGZO films were transparent (>70%) with a minimum electrical resistivity 10.5×10-3 Ω cm.

  13. Optical characterization of Sol-Gel ZnO:Al thin films

    NASA Astrophysics Data System (ADS)

    Ivanova, T.; Harizanova, A.; Koutzarova, T.; Vertruyen, B.

    2016-03-01

    This paper presents a sol-gel technological process for preparing thin films of ZnO and ZnO:Al. The effect of annealing treatments (500, 600, 700 and 800 °C) on their properties was studied. The structural evolution with the temperature was investigated by using X-Ray diffraction (XRD). Fourier Transform Infrared (FTIR) and UV-VIS spectrophotometry were applied to characterizing the films' vibrational and optical properties. The ZnO and ZnO:Al films possessed a polycrystalline structure. The films studied are highly transparent in the visible spectral range. The optical band gap values and the haze parameter were also determined.

  14. Optical and magneto-optical properties of metal phthalocyanine and metal porphyrin thin films.

    PubMed

    Birnbaum, Tobias; Hahn, Torsten; Martin, Claudia; Kortus, Jens; Fronk, Michael; Lungwitz, Frank; Zahn, Dietrich R T; Salvan, Georgeta

    2014-03-12

    The optical constants together with the magneto-optical Voigt constants of several phthalocyanine (Pc) and methoxy functionalized tetraphenylporphyrin (TMPP) thin films prepared on silicon substrates are presented. The materials investigated are MePc with Me = Fe, Co, Ni, Cu, Zn and MeTMPP with Me = Cu, Ni. We also compared our results to the metal-free H2Pc, H2TPP and H2TMPP. The experimental results will be supported by electronic structure calculations based on density functional theory (DFT) and interpreted using the perimeter model initially proposed by Platt. The model allows for qualitative understanding of the forbidden character of transitions in planar, aromatic molecules, and is able to qualify differences between Pc and TMPP type materials.

  15. Silver Nanowire Networks as Flexible, Transparent, Conducting Films: Extremely High DC to Optical Conductivity Ratios.

    PubMed

    De, Sukanta; Higgins, Thomas M; Lyons, Philip E; Doherty, Evelyn M; Nirmalraj, Peter N; Blau, Werner J; Boland, John J; Coleman, Jonathan N

    2009-07-28

    We have used aqueous dispersions of silver nanowires to prepare thin, flexible, transparent, conducting films. The nanowires are of length and diameter close to 6.5 μm and 85 nm, respectively. At low thickness, the films consist of networks but appear to become bulk-like for mean film thicknesses above ∼160 nm. These films can be very transparent with optical transmittance reaching as high as 92% for low thickness. The transmittance (550 nm) decreases with increasing thickness, consistent with an optical conductivity of 6472 S/m. The films are also very uniform; the transmittance varies spatially by typically <2%. The sheet resistance decreases with increasing thickness, falling below 1 Ω/◻ for thicknesses above 300 nm. The DC conductivity increases from 2 × 10(5) S/m for very thin films before saturating at 5 × 10(6) S/m for thicker films. Similarly, the ratio of DC to optical conductivity increases with increasing thickness from 25 for the thinnest films, saturating at ∼500 for thicknesses above ∼160 nm. We believe this is the highest conductivity ratio ever observed for nanostructured films and is matched only by doped metal oxide films. These nanowire films are electromechanically very robust, with all but the thinnest films showing no change in sheet resistance when flexed over >1000 cycles. Such results make these films ideal as replacements for indium tin oxide as transparent electrodes. We have prepared films with optical transmittance and sheet resistance of 85% and 13 Ω/◻, respectively. This is very close to that displayed by commercially available indium tin oxide.

  16. Selected area chemical vapor deposition of thin films for conductometric microelectronic chemical sensors

    NASA Astrophysics Data System (ADS)

    Majoo, Sanjeev

    Recent advances in microelectronics and silicon processing have been exploited to fabricate miniaturized chemical sensors. Although the capability of chemical sensing technology has grown steadily, it has been outpaced by the increasing demands for more reliable, inexpensive, and selective sensors. The diversity of applications requires the deployment of different sensing materials that have rich interfacial chemistry. However, several promising sensor materials are often incompatible with silicon micromachining and their deposition requires complicated masking steps. The new approach described here is to first micromachine a generic, instrumented, conductometric, microelectronic sensor platform that is fully functional except for the front-end sensing element. This generic platform contains a thin dielectric membrane, an integrated boron-doped silicon heater, and conductance electrodes. The membrane has low thermal mass and excellent thermal isolation. A proprietary selected-area chemical vapor deposition (SACVD) process in a cold-wall reactor at low pressures was then used to achieve maskless, self-lithographic deposition of thin films. The temperature-programmable integrated microheater initiates localized thermal decomposition/reaction of suitable CVD precursors confined to a small heated area (500 mum in diameter), and this creates the active sensing element. Platinum and titania (TiOsb2) films were deposited from pyrolysis of organometallic precursors, tetrakistrifluorophosphine platinum Pt(PFsb3)sb4 and titanium tetraisopropoxide Ti(OCH(CHsb3)sb2rbrack sb4, respectively. Deposition of gold metal films from chlorotriethylphosphine gold (Csb2Hsb5)sb3PAuCl precursor was also attempted but without success. The conductance electrodes permit in situ monitoring of film growth. The as-deposited films were characterized in situ by conductance measurements and optical microscopy and ex situ by electron microscopy and spectroscopy methods. Devices equipped with

  17. Ultrahigh-Resolution Measurement by Optical Coherence Tomography of Dynamic Tear Film Changes on Contact Lenses

    PubMed Central

    Chen, Qi; Tao, Aizhu; Shen, Meixiao; Jiao, Shuliang; Lu, Fan

    2010-01-01

    Purpose. To determine the dynamic pre- and postlens tear film (PLTF and PoLTF) thicknesses by using optical coherence tomography (OCT). Methods. Ultrahigh-resolution OCT was used to image the tear film of 22 subjects before and after contact lens wear. A soft lens with 1 drop of artificial tears on its concave surface was inserted onto one randomly selected eye. OCT images were taken before insertion, immediately afterward, and every 2 minutes for 10 minutes. For the contralateral eye, the lens inserted was not prewetted on the concave surface. OCT images were taken before insertion, immediately afterward, and at 3 minutes. Then another drop was instilled, and images were taken immediately afterward and every 2 minutes for 10 minutes. Images were processed by custom software to yield tear film thickness. Results. The thickness of precorneal tear film (PCTF) was 1.9 ± 0.9 μm. The PoLTF was visualized clearly in all cases immediately after lens insertion, with 1 drop on the lens concave surface. Through the first 6 minutes after insertion, the PoLTF was greater than the PCTF. The PLTF (n = 12) and PoLTF (n = 9) were visualized immediately after lens insertion. After 3 minutes, the PLTF in most subjects and PoLTF in all subjects were invisible. The thickness of the PLTF increased after the instillation of artificial tears, whereas the PoLTF did not at any checkpoint for 10 minutes. Conclusions. Ultrahigh-resolution OCT is a promising tool for measuring the tear film. The PoLTF did not increase after instillation of artificial tears. PMID:19933178

  18. Optical properties of thin gold films applied to Schottky barrier solar cells

    NASA Technical Reports Server (NTRS)

    YEH Y. M.

    1974-01-01

    The Schottky barrier solar cell is considered a possible candidate for converting solar to electrical energy both for space and terrestrial applications. Knowledge of the optical constants of the ultrathin metal film used in the cell is essential for analyzing and designing higher efficiency Schottky barrier cells. The optical constants of 7.5 -nm (75-A) gold films on gallium arsenide have been obtained. In addition, the absolute collection efficiency of Schottky barrier solar cells has been determined from measured spectral response and optical constants of the gold film.

  19. Thermal cycling and the optical and electrical characterization of self-assembled multilayer Nile Blue A-gold thin films

    SciTech Connect

    Geist, Brian; Spillman, William B.; Claus, Richard O

    2005-10-20

    Some laser applications produce high power densities that can be dangerous to equipment and operators. We have fabricated thin-film coatings by using molecular electrostatic self-assembly to create a spectrally selective absorbing coating that is able to withstand thermal fluctuations from -20 deg. C to 120 deg. C. We made the thin-film coatings by alternating deposition of an organic dye and gold colloidal nanoparticles onto glass substrates. Nile Blue A perchlorate, with a maximum absorbance slightly above 632 nm, was chosen as the organic dye. Strong coupling between the dye molecules and the gold nanoparticles provides a redshift that increases as the film's thickness is increased. The incorporation of the gold colloidal nanoparticles also decreases the resistivity of the film. The resistivity of the film was measured with a four-point probe and found to be {approx}10 {omega}/cm for the two samples measured. Atomic-force microscopy was used to show that film thickness increased 2.4nm per bilayer. The optical properties of the film were measured at the end of every 5 thermal cycles from -20 deg. C to 120 deg. C, and negligible degradation was observed after 30 cycles.

  20. Thermal cycling and the optical and electrical characterization of self-assembled multilayer nile blue A-gold thin films.

    PubMed

    Geist, Brian; Spillman, William B; Claus, Richard O

    2005-10-20

    Some laser applications produce high power densities that can be dangerous to equipment and operators. We have fabricated thin-film coatings by using molecular electrostatic self-assembly to create a spectrally selective absorbing coating that is able to withstand thermal fluctuations from -20 degrees C to 120 degrees C. We made the thin-film coatings by alternating deposition of an organic dye and gold colloidal nanoparticles onto glass substrates. Nile Blue A perchlorate, with a maximum absorbance slightly above 632 nm, was chosen as the organic dye. Strong coupling between the dye molecules and the gold nanoparticles provides a redshift that increases as the film's thickness is increased. The incorporation of the gold colloidal nanoparticles also decreases the resistivity of the film. The resistivity of the film was measured with a four-point probe and found to be approximately 10 omega/cm for the two samples measured. Atomic-force microscopy was used to show that film thickness increased 2.4 nm per bilayer. The optical properties of the film were measured at the end of every 5 thermal cycles from -20 degrees C to 120 degrees C, and negligible degradation was observed after 30 cycles.

  1. Thermal cycling and the optical and electrical characterization of self-assembled multilayer Nile Blue A gold thin films

    NASA Astrophysics Data System (ADS)

    Geist, Brian; Spillman, William B.; Claus, Richard O.

    2005-10-01

    Some laser applications produce high power densities that can be dangerous to equipment and operators. We have fabricated thin-film coatings by using molecular electrostatic self-assembly to create a spectrally selective absorbing coating that is able to withstand thermal fluctuations from -20 °C to 120 °C. We made the thin-film coatings by alternating deposition of an organic dye and gold colloidal nanoparticles onto glass substrates. Nile Blue A perchlorate, with a maximum absorbance slightly above 632 nm, was chosen as the organic dye. Strong coupling between the dye molecules and the gold nanoparticles provides a redshift that increases as the film's thickness is increased. The incorporation of the gold colloidal nanoparticles also decreases the resistivity of the film. The resistivity of the film was measured with a four-point probe and found to be ˜10 Ω/cm for the two samples measured. Atomic-force microscopy was used to show that film thickness increased 2.4nm per bilayer. The optical properties of the film were measured at the end of every 5 thermal cycles from -20 °C to 120 °C, and negligible degradation was observed after 30 cycles.

  2. Selective Plasma Deposition of Fluorocarbon Films on SAMs

    NASA Technical Reports Server (NTRS)

    Crain, Mark M., III; Walsh, Kevin M.; Cohn, Robert W.

    2006-01-01

    A dry plasma process has been demonstrated to be useful for the selective modification of self-assembled monolayers (SAMs) of alkanethiolates. These SAMs are used, during the fabrication of semiconductor electronic devices, as etch masks on gold layers that are destined to be patterned and incorporated into the devices. The selective modification involves the formation of fluorocarbon films that render the SAMs more effective in protecting the masked areas of the gold against etching by a potassium iodide (KI) solution. This modification can be utilized, not only in the fabrication of single electronic devices but also in the fabrication of integrated circuits, microelectromechanical systems, and circuit boards. In the steps that precede the dry plasma process, a silicon mold in the desired pattern is fabricated by standard photolithographic techniques. A stamp is then made by casting polydimethylsiloxane (commonly known as silicone rubber) in the mold. The stamp is coated with an alkanethiol solution, then the stamp is pressed on the gold layer of a device to be fabricated in order to deposit the alkanethiol to form an alkanethiolate SAM in the desired pattern (see figure). Next, the workpiece is exposed to a radio-frequency plasma generated from a mixture of CF4 and H2 gases. After this plasma treatment, the SAM is found to be modified, while the exposed areas of gold remain unchanged. This dry plasma process offers the potential for forming masks superior to those formed in a prior wet etching process. Among the advantages over the wet etching process are greater selectivity, fewer pin holes in the masks, and less nonuniformity of the masks. The fluorocarbon films formed in this way may also be useful as intermediate layers for subsequent fabrication steps and as dielectric layers to be incorporated into finished products.

  3. Ultra-Smooth As-Deposited Optical Films

    DTIC Science & Technology

    2007-11-02

    thin films with state-of-the-art properties , specifically ultrasmooth surfaces, high packing density, refractive index close... properties of thin films ; in particular, the surface roughness of the thin films . And secondarily, the lifetime of the Cs source is important. In other... Film Deposition Initially, the deposition system was utilized to deposit single layer thin films of titanium oxide ( TiO2 ) and silicon oxide

  4. Preparation of silica thin films by novel wet process and study of their optical properties.

    PubMed

    Im, Sang-Hyeok; Kim, Nam-Jin; Kim, Dong-Hwan; Hwang, Cha-Won; Yoon, Duck-Ki; Ryu, Bong-Ki

    2012-02-01

    Silicon dioxide (SiO2) thin films have gained considerable attention because of their various industrial applications. For example, SiO2 thin films are used in superhydrophilic self-cleaning surface glass, UV protection films, anti-reflection coatings, and insulating materials. Recently, many processes such as vacuum evaporation, sputtering, chemical vapor deposition, and spin coating have been widely applied to prepare thin films of functionally graded materials. However, these processes suffer from several engineering problems. For example, a special apparatus is required for the deposition of films, and conventional wet processes are not suitable for coating the surfaces of substrates with a large surface area and complex morphology. In this study, we investigated the film morphology and optical properties of SiO2 films prepared by a novel technique, namely, liquid phase deposition (LPD). Images of the SiO2 films were obtained by scanning electron microscopy (SEM) and atomic force microscopy (AFM) in order to study the surface morphology of these films: these images indicate that films deposited with different reaction times were uniform and dense and were composed of pure silica. Optical properties such as refractive index and transmittance were estimated by UV-vis spectroscopy and ellipsometry. SiO2 films with porous structures at the nanometer scale (100-250 nm) were successfully produced by LPD. The deposited film had excellent transmittance in the visible wavelength region.

  5. Microstructure, hydrogenation and optical behavior of Mg-Ni multilayer films deposited by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Wang, X. L.; Qiao, Y. Q.; Xia, X. H.; Tu, J. P.

    2011-04-01

    Mg-Ni multilayer films with sequential Mg and Ni layers were prepared by direct current magnetron sputtering. The substrate temperature influences the microstructure of the films greatly. The film deposited at 298 K exhibits multilayered structure, while the film shows nanocrystalline/amorphous composite structure at the deposition temperature of 473 K. The optical properties between hydrogenation/dehydrogenation states of the films were performed using spectrophotometer in visible light region. The film deposited at 473 K can switch from mirror-like metallic state towards brownish yellow transparent state under 0.6 MPa H2 at 298 K, and the optical transmittance modulation reaches up to 20% both at a wavelength of 770 nm and IR region, while the film deposited at 298 K exhibits low optical change, and the optical switching behavior can hardly be found. The extra free energy stored in the boundary of the nanocrystallines benefits the formation of magnesium-based hydride, resulting in the enhancement of the optical switching properties of the Mg-Ni film deposited at 473 K.

  6. Structural and optical properties of nanostructure CdZnO films.

    PubMed

    Gupta, R K; Cavas, M; Yakuphanoglu, F

    2012-09-01

    CdZnO thin films with different ratio of CdO and ZnO (3:1, 1:1, and 1:3) were grown on glass substrate using sol-gel spin coating method. The morphology of the CdZnO films depends on the amount of ZnO and CdO in the films. The optical band gap of the CdZnO films depends on the compositions of CdO and ZnO. Films having higher amount of CdO shows the presence of grains along with the fiber nature of ZnO, whereas the film with lower percentage of CdO shows fiber nature of the film very similar to pure ZnO film. The optical bandgap of CdZnO (3:1), CdZnO (1:1), and CdZnO (1:3) films was calculated to be 2.80, 2.49, and 2.52 eV, respectively. Other optical properties such as refractive index, extinction coefficient, and dielectric constants were calculated using the optical data. The volume and surface energy loss functions were also calculated and observed to increase with increase in the photon energy. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Nonlinear optical parameters of nanocrystalline AZO thin film measured at different substrate temperatures

    NASA Astrophysics Data System (ADS)

    Jilani, Asim; Abdel-wahab, M. Sh; Al-ghamdi, Attieh A.; Dahlan, Ammar sadik; Yahia, I. S.

    2016-01-01

    The 2.2 wt% of aluminum (Al)-doped zinc oxide (AZO) transparent and preferential c-axis oriented thin films were prepared by using radio frequency (DC/RF) magnetron sputtering at different substrate temperature ranging from room temperature to 200 °C. For structural analysis, X-ray Diffraction (XRD) and Atomic Force Electron Microscope (AFM) was used for morphological studies. The optical parameters such as, optical energy gap, refractive index, extinction coefficient, dielectric loss, tangent loss, first and third order nonlinear optical properties of transparent films were investigated. High transmittance above 90% and highly homogeneous surface were observed in all samples. The substrate temperature plays an important role to get the best transparent conductive oxide thin films. The substrate temperature at 150 °C showed the growth of highly transparent AZO thin film. Energy gap increased with the increased in substrate temperature of Al doped thin films. Dielectric constant and loss were found to be photon energy dependent with substrate temperature. The change in substrate temperature of Al doped thin films also affect the non-liner optical properties of thin films. The value of χ(3) was found to be changed with the grain size of the thin films that directly affected by the substrate temperature of the pure and Al doped ZnO thin films.

  8. Mechanism of resonant perfect optical absorption in dielectric film supporting metallic grating structures.

    PubMed

    Chen, Xiumei; Yan, Xiaopeng; Li, Ping; Mou, Yongni; Wang, Wenqiang; Guan, Zhiqiang; Xu, Hongxing

    2016-08-22

    The mechanism of resonant perfect optical absorbers is quantitatively revealed by the coupled mode method for the air/grating/dielectric film/air four region system. The sufficient and necessary conditions of the perfect optical absorption are derived from the interface scattering coefficients analyses. The coupling of the Fabry-Perot modes in the grating slits and non-zero order quasi waveguide modes in the dielectric film play a key role for the perfect optical absorption when the light is incident from the grating side. The analytical sufficient and necessary conditions of the perfect optical absorption provide an efficient tool towards geometry design for the perfect optical absorption at the specific wavelengths. The advantages of a widely tunable perfect optical absorption wavelength, a high Q factor and the confined energy loss on metal surfaces make the air/grating/film/air structures promising for applications in sensing, modulation and detection.

  9. (abstract) Optical Scattering and Surface Microroughness of Ion Beam Deposited Au and Pt Thin Films

    NASA Technical Reports Server (NTRS)

    Al-Jumaily, Ghanim A.; Raouf, Nasrat A.; Edlou, Samad M.; Simons, John C.

    1994-01-01

    Thin films of gold and platinum have been deposited onto superpolished fused silica substrates using thermal evaporation, ion assisted deposition (IAD), and ion assisted sputtering. The influence of ion beam flux, thin film material, and deposition rate on the films microroughness have been investigated. Short range surface microroughness of the films has been examined using scanning tunneling microscopy (STM) and atomic force microscopy (AFM). Long range surface microroughness has been characterized using an angle resolved optical scatterometer. Results indicate that ion beam deposited coatings have improved microstructure over thermally evaporated films.

  10. Structural, optical and electronic structure studies of Al doped ZnO thin films

    NASA Astrophysics Data System (ADS)

    Devi, Vanita; Kumar, Manish; Shukla, D. K.; Choudhary, R. J.; Phase, D. M.; Kumar, Ravindra; Joshi, B. C.

    2015-07-01

    Structural, optical and electronic structure of Al doped ZnO thin films grown using pulsed laser deposition on glass substrate are investigated. X-ray diffraction measurements reveal that all the films are textured along the c-axis and have wurtzite structure. Al doping in ZnO films leads to increase in grain size due to relaxation in compressive stress. Enhancement in band gap of ZnO films with the Al doping is also noticed which can be ascribed to the Brustein-Moss shift. The changes in the electronic structure caused by Al in the doped thin film samples are understood through X-ray absorption measurements.

  11. Elasto-Optical Properties of Thin Polymer Films by Prism Coupling Technique

    NASA Astrophysics Data System (ADS)

    Ay, Feridun; Agan, Sedat; Kocabas, Askin; Aydinli, Atilla

    2004-05-01

    Reliable measurement of stress dependent refractive index of thin polymer films has been achieved. The effect of the applied stress on the refractive index and birefringence of the films was investigated. The out-of-plane elastic moduli of the thin polymer films were deduced by using the same prism coupling setup. Three dimensional finite element method (FEM) analysis was used to obtain the principal stresses for each polymer film and combining them with the stress dependent refractive index measurements, the elasto-optic coefficients of the polymer films were determined, for the first time.

  12. Thin film technologies for optoelectronic components in fiber optic communication

    NASA Astrophysics Data System (ADS)

    Perinati, Agostino

    1998-02-01

    will grow at an annual average rate of 22 percent from 1.3 million fiber-km in 1995 to 3.5 million fiber-km in 2000. The worldwide components market-cable, transceivers and connectors - 6.1 billion in 1994, is forecasted to grow and show a 19 percent combined annual growth rate through the year 2000 when is predicted to reach 17.38 billion. Fiber-in-the-loop and widespread use of switched digital services will dominate this scenario being the fiber the best medium for transmitting multimedia services. As long as communication will partially replace transportation, multimedia services will push forward technology for systems and related components not only for higher performances but for lower cost too in order to get the consumers wanting to buy the new services. In the long distance transmission area (trunk network) higher integration of electronic and optoelectronic functions are required for transmitter and receiver in order to allow for higher system speed, moving from 2.5 Gb/s to 5, 10, 40 Gb/s; narrow band wavelength division multiplexing (WDM) filters are required for higher transmission capacity through multiwavelength technique and for optical amplifier. In the access area (distribution network) passive components as splitters, couplers, filters are needed together with optical amplifiers and transceivers for point-to-multipoint optical signal distribution: main issue in this area is the total cost to be paid by the customer for basic and new services. Multimedia services evolution, through fiber to the home and to the desktop approach, will be mainly affected by the availability of technologies suitable for component consistent integration, high yield manufacturing processes and final low cost. In this paper some of the optoelectronic components and related thin film technologies expected to mainly affect the fiber optic transmission evolution, either for long distance telecommunication systems or for subscriber network, are presented.

  13. Six mode selective fiber optic spatial multiplexer.

    PubMed

    Velazquez-Benitez, A M; Alvarado, J C; Lopez-Galmiche, G; Antonio-Lopez, J E; Hernández-Cordero, J; Sanchez-Mondragon, J; Sillard, P; Okonkwo, C M; Amezcua-Correa, R

    2015-04-15

    Low-loss all-fiber photonic lantern (PL) mode multiplexers (MUXs) capable of selectively exciting the first six fiber modes of a multimode fiber (LP01, LP11a, LP11b, LP21a, LP21b, and LP02) are demonstrated. Fabrication of the spatial mode multiplexers was successfully achieved employing a combination of either six step or six graded index fibers of four different core sizes. Insertion losses of 0.2-0.3 dB and mode purities above 9 dB are achieved. Moreover, it is demonstrated that the use of graded index fibers in a PL eases the length requirements of the adiabatic tapered transition and could enable scaling to large numbers.

  14. Selectively Patterning Polymer Opal Films via Microimprint Lithography

    PubMed Central

    Ding, Tao; Zhao, Qibin; Smoukov, Stoyan K; Baumberg, Jeremy J

    2014-01-01

    Large-scale structural color flexible coatings have been hard to create, and patterning color on them is key to many applications, including large-area strain sensors, wall-size displays, security devices, and smart fabrics. To achieve controlled tuning, a micro-imprinting technique is applied here to pattern both the surface morphology and the structural color of the polymer opal films (POFs). These POFs are made of 3D ordered arrays of hard spherical particles embedded inside soft shells. The soft outer shells cause the POFs to deform upon imprinting with a pre-patterned stamp, driving a flow of the soft polymer and a rearrangement of the hard spheres within the films. As a result, a patterned surface morphology is generated within the POFs and the structural colors are selectively modified within different regions. These changes are dependent on the pressure, temperature, and duration of imprinting, as well as the feature sizes in the stamps. Moreover, the pattern geometry and structural colors can then be further tuned by stretching. Micropattern color generation upon imprinting depends on control of colloidal transport in a polymer matrix under shear flow and brings many potential properties including stretchability and tunability, as well as being of fundamental interest. PMID:26167447

  15. Selectively Patterning Polymer Opal Films via Microimprint Lithography.

    PubMed

    Ding, Tao; Zhao, Qibin; Smoukov, Stoyan K; Baumberg, Jeremy J

    2014-11-01

    Large-scale structural color flexible coatings have been hard to create, and patterning color on them is key to many applications, including large-area strain sensors, wall-size displays, security devices, and smart fabrics. To achieve controlled tuning, a micro-imprinting technique is applied here to pattern both the surface morphology and the structural color of the polymer opal films (POFs). These POFs are made of 3D ordered arrays of hard spherical particles embedded inside soft shells. The soft outer shells cause the POFs to deform upon imprinting with a pre-patterned stamp, driving a flow of the soft polymer and a rearrangement of the hard spheres within the films. As a result, a patterned surface morphology is generated within the POFs and the structural colors are selectively modified within different regions. These changes are dependent on the pressure, temperature, and duration of imprinting, as well as the feature sizes in the stamps. Moreover, the pattern geometry and structural colors can then be further tuned by stretching. Micropattern color generation upon imprinting depends on control of colloidal transport in a polymer matrix under shear flow and brings many potential properties including stretchability and tunability, as well as being of fundamental interest.

  16. Optical and morphological characteristics of organic thin films for optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Zhong, Zhiyou; Sun, Fenglou

    2007-12-01

    Organic semiconductor thin films of tri-(8-hydroxyquinoline)-aluminum (Alq), 9,10-di-(2-naphthyl)-anthracene (ADN), and N,N'bis(naphthalen-1-yl)-N,N'bis(phenyl)-benzidine (NPB) for optoelectronic devices were deposited onto glass substrates by vacuum sublimation technique. The surface morphology and roughness of the thin film were characterized by means of atomic force microscopy (AFM). Experimental results indicate that all thin films present similar granular topography but different surface roughness. In addition, the optical transmittance spectra of thin films were measured by a double beam spectrophotometer and their corresponding optical properties were investigated. The complex refractive index and the optical band gap of thin films were obtained, respectively. Meanwhile, the dispersion behavior of the refractive index was studied in terms of Wemple-DiDomenico single oscillator model, and the oscillator parameters were achieved.

  17. AFM investigation and optical band gap study of chemically deposited PbS thin films

    NASA Astrophysics Data System (ADS)

    Zaman, S.; Mansoor, M.; Abubakar; Asim, M. M.

    2016-08-01

    The interest into deposition of nanocrystalline PbS thin films, the potential of designing and tailoring both the topographical features and the band gap energy (Eg) by controlling growth parameters, has significant technological importance. Nanocrystalline thin films of lead sulfide were grown onto glass substrates by chemical bath deposition (CBD) method. The experiments were carried out by varying deposition temperature. We report on the modification of structural and optical properties as a function of deposition temperature. The morphological changes of the films were analyzed by using SEM and AFM. AFM was also used to calculate average roughness of the films. XRD spectra indicated preferred growth of cubic phase of PbS films in (200) direction with increasing deposition time. Optical properties have been studied by UV-Spectrophotometer. From the diffused reflectance spectra we have calculated the optical Eg shift from 0.649-0.636 eV with increasing deposition time.

  18. W:Al2O3 nanocomposite thin films with tunable optical properties prepared by atomic layer deposition

    DOE PAGES

    Babar, Shaista; Mane, Anil U.; Yanguas-Gil, Angel; ...

    2016-06-17

    Here, a systematic alteration in the optical properties of W:Al2O3 nanocomposite films is demonstrated by precisely varying the W cycle percentage (W%) from 0 to 100% in Al2O3 during atomic layer deposition. The direct and indirect band energies of the nanocomposite materials decrease from 5.2 to 4.2 eV and from 3.3 to 1.8 eV, respectively, by increasing the W% from 10 to 40. X-ray absorption spectroscopy reveals that, for W% < 50, W is present in both metallic and suboxide states, whereas, for W% ≥ 50, only metallic W is seen. This transition from dielectric to metallic character at W%more » ~ 50 is accompanied by an increase in the electrical and thermal conductivity and the disappearance of a clear band gap in the absorption spectrum. The density of the films increases monotonically from 3.1 g/cm3 for pure Al2O3 to 17.1 g/cm3 for pure W, whereas the surface roughness is greatest for the W% = 50 films. The W:Al2O3 nanocomposite films are thermally stable and show little change in optical properties upon annealing in air at 500 °C. These W:Al2O3 nanocomposite films show promise as selective solar absorption coatings for concentrated solar power applications.« less

  19. Dielectric and optical properties of sputtered thin films

    NASA Astrophysics Data System (ADS)

    Tanguay, A. R., Jr.

    1984-07-01

    Of critical importance to the eventual performance of numerous coherent optical image processors and highly parallel computers is the development of a high speed, recyclable, linear, high resolution, selectively erasable image storage transducer operable in nearly real time. Applications for such a transducer abound, including incoherent-to-coherent conversion, pattern recognition and image feature extraction, level slicing, edge enhancement, low light level image integration, scratch pad memory, and page composition for data entry in holographic memory systems. In response to this need, a wide variety of candidate devices have been proposed in the past ten years, based on photochromic, liquid crystal, photorefractive, magnetooptic, electrooptic, deformable membrane, thermoplastic, photodichroic, and ambidextrous effects in numerous configurations. The device category comprised of Electrooptic Spatial Light Modulators contains a number of leading candidates, due to a combination of wide dynamic range, high sensitivity, intermediate storage time, relative simplicity of construction and operation, and long term durability. This category includes the Pockels Readout Optical Modulator or PROM, a Soviet modification of th PROM called the PRIZ, the Microchannel Spatial Light Modulator, the TITUS and photo-TITUS, and the Photorefractive Incoherent-to-Coherent Optical Converter.

  20. Social Factors in Health Care: An Evaluation of Selected Films and Videotapes.

    ERIC Educational Resources Information Center

    Hunt, Gerard J.; Mondell, Allen S.

    Reviews of selected films and videotapes which illustrate the relationship between social factors and health care are presented in this catalog. Some 41 films were chosen for their proven ability to present social and behavioral science concepts to medical students and others involved in the health sciences. The films relate to two areas of health…

  1. Social Factors in Health Care: An Evaluation of Selected Films and Videotapes.

    ERIC Educational Resources Information Center

    Hunt, Gerard J.; Mondell, Allen S.

    Reviews of selected films and videotapes which illustrate the relationship between social factors and health care are presented in this catalog. Some 41 films were chosen for their proven ability to present social and behavioral science concepts to medical students and others involved in the health sciences. The films relate to two areas of health…

  2. Elements of adaptive optics based on metallized polymer films

    NASA Astrophysics Data System (ADS)

    Voliak, T. B.; Krasiuk, I. K.; Pashinin, P. P.

    Results of an experimental study of the stability of metallized polymer films exposed to laser radiation at wavelengths of 1.06 and 10.6 microns are reported, and methods for fabricating variable-curvature mirrors from these films are discussed. Formulas are presented for calculating the shape of film mirrors as a function of the pressure acting on the film, mounting contour, and film properties. The performance of film mirrors is investigated experimentally in a pulsed CO2 laser with stable and unstable resonators.

  3. Structural and optical properties of Tin sulphide thin films

    SciTech Connect

    Akkari, A.; Ben Nasr, T.; Kamoun, N.

    2007-09-19

    Tin sulphide SnS thin films were deposited on glass substrates using the chemical bath deposition technique (CBD). By investigating the influence of triethanolamine (TEA) concentration on the properties of deposited films, we obtained the optimum deposition parameter. These films were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) analysis and spectrophotometric measurements. The obtained thin films exhibit the orthorhombic structure and the direct band gap energy is found to be about 1.65 eV, for films prepared at TEA concentration films equal to 13.5 M.

  4. Structural and nonlinear optical behavior of Ag-doped ZnO films

    NASA Astrophysics Data System (ADS)

    Tan, Ming-Yue; Yao, Cheng-Bao; Yan, Xiao-Yan; Li, Jin; Qu, Shu-Yang; Hu, Jun-Yan; Sun, Wen-Jun; Li, Qiang-Hua; Yang, Shou-Bin

    2016-01-01

    We present the structural and nonlinear optical behavior of Ag-doped ZnO (AZO) films prepared by magnetron sputtering. The structural of AZO films are systematically investigated by X-ray diffraction (XRD) and scanning electronic microscopy (SEM), respectively. The results show that AZO films can still retain a wurtzite structure, although the c-axis as preferred orientation is decreased by Ag doping. As the amounts of the Ag dopant were increased, the crystallinity as well as the absorptivity and optical band gap were increased. Moreover, the nonlinear optical characterized of the AZO films was studied using Z-scan technique. These samples show self-defocusing nonlinearity and good nonlinear absorption behavior which increases with increasing Ag volume fraction. AZO is a potential nanocomposite material for the development of nonlinear optical devices with a relatively small limiting threshold.

  5. Structural and optical investigation of Te-based chalcogenide thin films

    SciTech Connect

    Sharma, Rita Sharma, Shaveta; Thangaraj, R.; Mian, M.; Chander, Ravi; Kumar, Praveen

    2015-05-15

    We report the structural and optical properties of thermally evaporated Bi{sub 2}Te{sub 3}, In{sub 2}Te{sub 3} and InBiTe{sub 3} films by using X-ray diffraction, optical and Raman Spectroscopy techniques. The as-prepared thin films were found to be Semi-crystalline by X-ray diffraction. Particle Size and Strain has been calculated from XRD data. The optical constants, film thickness, refractive index and optical band gap (E{sub g}) has been reported for In{sub 2}Te{sub 3}, InBiTe{sub 3} films. Raman Spectroscopy was performed to investigate the effect of Bi, In, on lattice vibration and chemical bonding in Te based chalcogenide glassy alloys.

  6. Selective and reversible ammonia gas detection with nanoporous film functionalized silicon photonic micro-ring resonator.

    PubMed

    Yebo, Nebiyu A; Sree, Sreeprasanth Pulinthanathu; Levrau, Elisabeth; Detavernier, Christophe; Hens, Zeger; Martens, Johan A; Baets, Roel

    2012-05-21

    Portable, low cost and real-time gas sensors have a considerable potential in various biomedical and industrial applications. For such applications, nano-photonic gas sensors based on standard silicon fabrication technology offer attractive opportunities. Deposition of high surface area nano-porous coatings on silicon photonic sensors is a means to achieve selective, highly sensitive and multiplexed gas detection on an optical chip. Here we demonstrate selective and reversible ammonia gas detection with functionalized silicon-on-insulator optical micro-ring resonators. The micro-ring resonators are coated with acidic nano-porous aluminosilicate films for specific ammonia sensing, which results in a reversible response to NH(3)with selectivity relative to CO(2). The ammonia detection limit is estimated at about 5 ppm. The detectors reach a steady response to NH(3) within 30 and return to their base level within 60 to 90 seconds. The work opens perspectives on development of nano-photonic sensors for real-time, non-invasive, low cost and light weight biomedical and industrial sensing applications.

  7. Optical hydrogen sensitivity of Pd-metal oxide composite films prepared on fiber optics

    NASA Astrophysics Data System (ADS)

    Maciak, Erwin; Opilski, Zbigniew; Urbanczyk, Marian

    2005-09-01

    The paper presents an optical-fiber hydrogen sensor. The sensor utilises a layered Fabry-Perot interferometer and includes gasochromic metal oxides (V2O5, Nb2O5, CeO2). The structure contains at the end a multi-mode optical fiber as the sensing element. The sensor permits to detect and to measure the concentration of hydrogen in a gaseous medium. A comparison of the properties of selected gasochromic metal oxides in the interferometric sensor structures has been presented.

  8. Effect of substrate baking temperature on zinc sulfide and germanium thin films optical parameters

    NASA Astrophysics Data System (ADS)

    Liu, Fang; Gao, Jiaobo; Yang, Chongmin; Zhang, Jianfu; Liu, Yongqiang; Liu, Qinglong; Wang, Songlin; Mi, Gaoyuan; Wang, Huina

    2016-10-01

    ZnS and Ge are very normal optical thin film materials in Infrared wave. Studying the influence of different substrate baking temperature to refractive index and actual deposition rates is very important to promote optical thin film quality. In the same vacuum level, monitoring thickness and evaporation rate, we use hot evaporation to deposit ZnS thin film materials and use ion-assisted electron beam to deposit Ge thin film materials with different baking temperature. We measure the spectral transmittance with the spectrophotometer and calculate the actual deposition rates and the refractive index in different temperature. With the higher and higher temperature in a particular range, ZnS and Ge refractive index become higher and actual deposition rates become smaller. The refractive index of Ge film material change with baking temperature is more sensitive than ZnS. However, ZnS film actual deposition rates change with baking temperature is more sensitive than Ge.

  9. Structural and optical study of nanostructure of 4-cyanopyranoquinolinedione (CPQ) thin films

    NASA Astrophysics Data System (ADS)

    Soliman, H. S.; Ibrahim, M.; El-Mansy, M. A. M.; Atef, S. M.

    2017-10-01

    Thin films of 4-cyanopyranoquinolinedione, CPQ, with different thicknesses were deposited by thermal evaporation method. The structural properties of powder and thin films were investigated using X-ray diffraction technique. The crystal structure, lattice parameters and Miller indices of the powder were indexed. The crystalline size, strain and dislocation density were determined for powder and thin films. The optical properties of CPQ thin films were studied using spectrophotometric measurements of both transmittance and reflectance in the wavelength range 200-2500 nm. HOMO-LUMO band gap was determined by cyclic voltammetry. The calculation of optical band gap using absorption coefficient showed that the film has direct allowed transition with 3.02 eV energy gap. The normal dispersion of the refractive index of the films was described by Wemple-DiDomenico single oscillator model. Some dispersion parameters were calculated. Also, the real and imaginary parts of dielectric constant, volume and surface energy loss functions were estimated.

  10. Annealing effect on structural and optical properties of chemical bath deposited MnS thin film

    NASA Astrophysics Data System (ADS)

    Ulutas, Cemal; Gumus, Cebrail

    2016-03-01

    MnS thin film was prepared by the chemical bath deposition (CBD) method on commercial microscope glass substrate deposited at 30 °C. The as-deposited film was given thermal annealing treatment in air atmosphere at various temperatures (150, 300 and 450 °C) for 1 h. The MnS thin film was characterized by using X-ray diffraction (XRD), UV-vis spectrophotometer and Hall effect measurement system. The effect of annealing temperature on the structural, electrical and optical properties such as optical constants of refractive index (n) and energy band gap (Eg) of the film was determined. XRD measurements reveal that the film is crystallized in the wurtzite phase and changed to tetragonal Mn3O4 phase after being annealed at 300 °C. The energy band gap of film decreased from 3.69 eV to 3.21 eV based on the annealing temperature.

  11. Structural and optical properties of sintered Cd 1- xZn xS films

    NASA Astrophysics Data System (ADS)

    Kumar, Vipin; Singh, V.; Sharma, Sachin K.; Sharma, T. P.

    1998-11-01

    II-VI semiconductors are of great importance due to their applications in various electro-optic devices. Sulphides of zinc and cadmium have been utilized effectively in various opto-electronic devices. We have prepared sintered CdZnS films by the screen printing method. Wide band gap ternary films have wide application in solar cells. The structural and optical properties of these films have been studied. The band gap of these films are studied by reflection spectra in the wavelength range 300-600 nm. The films have a direct band gap which varies from 3.50 eV for zinc sulphide to 2.44 for cadmium sulphide. The X-ray diffraction pattern of these films for structural analysis is also reported.

  12. Optical fluoride sensor based on monomer-dimer equilibrium of scandium(III)-octaethylporphyrin in a plasticized polymeric film.

    PubMed

    Kang, Youngjea; Kampf, Jeff W; Meyerhoff, Mark E

    2007-08-29

    A fluoride-selective optical sensor based on scandium(III)-octaethylporphyrin (Sc(III)OEP) as an ionophore within a plasticized PVC film is described. The presence of fluoride ion in the aqueous sample phase increases the formation of a difluoro-bridged Sc(III)OEP dimer species in the polymer film. The ability of the Sc(III) porphyrin to form the dimeric structure in the presence of fluoride is confirmed by UV-vis spectroscopy and X-ray crystallography. For more practical sensing applications, a pH chromoionophore (ETH 7075) is added to the plasticized PVC film along with Sc(III)OEP and the observed optical response is based on coextraction of protons with sample phase fluoride to create the dimeric porphyrin and a protonated chromoionophore species. The selectivity pattern observed is F- > ClO4(-), SCN-, NO3(-) > Br-, Cl-. Only organic salicylate is a significant interferent. Fast and reversible fluoride response is observed over the range of 10(-4) to 10(-2) M fluoride, allowing use of the sensing film in a waveguide configuration for flow-injection measurements.

  13. Optical Fluoride Sensor Based on Monomer-Dimer Equilibrium of Scandium(III)-Octaethylporphyrin in a Plasticized Polymeric Film

    PubMed Central

    Kang, Youngjea; Kampf, Jeff W.; Meyerhoff, Mark E.

    2007-01-01

    A fluoride-selective optical sensor based on scandium(III) octaethylporphyrin (Sc(III)OEP) as an ionophore within a plasticized PVC film is described. The presence of fluoride ion in the aqueous sample phase increases the formation of a difluoro-bridged Sc(III)OEP dimer species in the polymer film. The ability of the Sc(III) porphyrin to form the dimeric structure in the presence of fluoride is confirmed by UV-Vis spectroscopy and X-ray crystallography. For more practical sensing applications, a pH chromoionophore (ETH 7075) is added to the plasticized PVC film along with Sc(III)OEP and the observed optical response is based on co-extraction of protons with sample phase fluoride to create the dimeric porphyrin and a protonated chromoionophore species. The selectivity pattern observed is F-≫ClO4-, SCN-, NO3->Br-, Cl-. Only organic salicylate is a significant interferent. Fast and reversible fluoride response is observed over the range of 10-4 ~10-2 M fluoride, allowing use of the sensing film in a waveguide configuration for flow-injection measurements. PMID:17719905

  14. The gamma irradiation effects on structural and optical properties of silk fibroin/HPMC blend films

    SciTech Connect

    Shetty, G. Rajesha; Rao, B. Lakshmeesha; Gowda, Mahadeva; Shivananda, C. S.; Asha, S.; Byrappa, K.; Sangappa, Y.

    2016-05-23

    In this paper the structural, chemical and optical properties of gamma irradiated silk fibroin/Hydroxypropyl methyl cellulose (SF-HPMC) blend films were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-visible spectroscopy. The results indicate that the gamma radiation did not affect significantly the primary structure of polypeptide arrangement in the blend films. But the optical properties of the blends changed with gamma irradiation dosage.

  15. The gamma irradiation effects on structural and optical properties of silk fibroin/HPMC blend films

    NASA Astrophysics Data System (ADS)

    Shetty, G. Rajesha; Rao, B. Lakshmeesha; Gowda, Mahadeva; Shivananda, C. S.; Asha, S.; Byrappa, K.; Sangappa, Y.

    2016-05-01

    In this paper the structural, chemical and optical properties of gamma irradiated silk fibroin/Hydroxypropyl methyl cellulose (SF-HPMC) blend films were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-visible spectroscopy. The results indicate that the gamma radiation did not affect significantly the primary structure of polypeptide arrangement in the blend films. But the optical properties of the blends changed with gamma irradiation dosage.

  16. Observation of the structural phase transition in manganite films by magneto-optical imaging.

    SciTech Connect

    Crabtree, G. W.; Lin, Y.; Miller, D. J.; Nikitenko, V. I.; Vlasko-Vlasov, V. K.; Welp, U.

    1999-08-31

    A high-resolution magneto-optical imaging technique is used to reveal the formation of twins occurring during a martensitic phase transition at {approximately}105K in LCMO films grown on STO substrates. The magnetic contrast arises due to the magneto-elastic tilts of the Mn - magnetic moments in the twins. Different magnetic structures are found in LCMO films grown on MgO, NGO, and LAO substrates showing the importance of the substrate material for the manganite film properties.

  17. Infrared reflection spectroscopy and optical constants of LiNbO3 films on crystal substrates

    NASA Astrophysics Data System (ADS)

    Novikova, N. N.; Yakovlev, V. A.; Medaglia, P. G.

    2017-01-01

    We have measured infrared reflectivity spectra of thin lithium niobate films of nanometer thickness, grown by a pulsed laser deposition technique using KrF-excimer laser (λ=248 nm) on the single crystalline substrates (sapphire, MgO, NdGaO3 and SrTiO3). Using the dispersion analysis technique, we have calculated thicknesses and optical constants of the films. The phonon parameters of the substrates and films are obtained.

  18. Ultraviolet response of film candidates for the solar optical telescope photometric filtergraph

    NASA Astrophysics Data System (ADS)

    Morgan, J. A.

    1983-10-01

    Measurements of UV response between 2000 and 3000 A of Kodak films 2415, Aerocon II 3412, and SO-415 are reported. The short wavelength cutoff of the response of all films studied lies near 2100 A, occurring as a gentle falloff starting near 2500 A. The sensitivity of the films appears to remain roughly constant from 2500 to 3000 A. Estimates of UV Gamma for 2415 and the effect of hard UV on the optics in the experiment are also discussed.

  19. Ultraviolet response of film candidates for the solar optical telescope photometric filtergraph

    NASA Technical Reports Server (NTRS)

    Morgan, J. A.

    1983-01-01

    Measurements of UV response between 2000 and 3000 A of Kodak films 2415, Aerocon II 3412, and SO-415 are reported. The short wavelength cutoff of the response of all films studied lies near 2100 A, occurring as a gentle falloff starting near 2500 A. The sensitivity of the films appears to remain roughly constant from 2500 to 3000 A. Estimates of UV Gamma for 2415 and the effect of hard UV on the optics in the experiment are also discussed.

  20. Infrared reflection spectroscopy and optical constants of LiNbO3 films on crystal substrates

    NASA Astrophysics Data System (ADS)

    Novikova, N. N.; Yakovlev, V. A.; Medaglia, P. G.

    2016-12-01

    We have measured infrared reflectivity spectra of thin lithium niobate films of nanometer thickness, grown by a pulsed laser deposition technique using KrF-excimer laser (λ=248 nm) on the single crystalline substrates (sapphire, MgO, NdGaO3 and SrTiO3). Using the dispersion analysis technique, we have calculated thicknesses and optical constants of the films. The phonon parameters of the substrates and films are obtained.

  1. Stress control in optical thin films by sputtering and electron beam evaporation.

    PubMed

    Tajima, Naoya; Murotani, Hiroshi; Matsumoto, Shigeharu; Honda, Hiromitsu

    2017-02-01

    It is necessary to control the internal stress of optical thin films in order to address problems such as peeling and cracking. Internal stress differs among films prepared by different deposition methods. We investigated the internal stress of films prepared by sputtering, electron beam (EB) evaporation, and a combination deposition method that we developed. The internal stress was successfully controlled, showing a value between that of EB evaporation and sputtering.

  2. Method to adjust multilayer film stress induced deformation of optics

    DOEpatents

    Mirkarimi, Paul B.; Montcalm, Claude

    2000-01-01

    A buffer-layer located between a substrate and a multilayer for counteracting stress in the multilayer. Depositing a buffer-layer having a stress of sufficient magnitude and opposite in sign reduces or cancels out deformation in the substrate due to the stress in the multilayer. By providing a buffer-layer between the substrate and the multilayer, a tunable, near-zero net stress results, and hence results in little or no deformation of the substrate, such as an optic for an extreme ultraviolet (EUV) lithography tool. Buffer-layers have been deposited, for example, between Mo/Si and Mo/Be multilayer films and their associated substrate reducing significantly the stress, wherein the magnitude of the stress is less than 100 MPa and respectively near-normal incidence (5.degree.) reflectance of over 60% is obtained at 13.4 nm and 11.4 nm. The present invention is applicable to crystalline and non-crystalline materials, and can be used at ambient temperatures.

  3. Electrical and optical properties of molybdenum doped zinc oxide films prepared by reactive RF magnetron sputtering

    SciTech Connect

    Reddy, R. Subba; Sreedhar, A.; Uthanna, S.

    2015-08-28

    Molybdenum doped zinc oxide (MZO) films were deposited on to glass substrates held at temperatures in the range from 303 to 673 K by reactive RF magnetron sputtering method. The chemical composition, crystallographic structure and surface morphology, electrical and optical properties of the films were determined. The films contained the molybdenum of 2.7 at. % in ZnO. The films deposited at 303 K were of X-ray amorphous. The films formed at 473 K were of nanocrystalline in nature with wurtzite structure. The crystallite size of the films was increased with the increase of substrate temperature. The optical transmittance of the films was in the visible range was 80–85%. The molybdenum (2.7 at %) doped zinc oxide films deposited at substrate temperature of 573 K were of nanocrystalline with electrical resistivity of 7.2×10{sup −3} Ωcm, optical transmittance of 85 %, optical band gap of 3.35 eV and figure of merit 30.6 Ω{sup −1}cm{sup −1}.

  4. Organoaluminophosphate sol-gel silica glass thin films for integrated optics

    NASA Astrophysics Data System (ADS)

    Touam, Tahar; Milova, Galina; Saddiki, Z.; Fardad, M. A.; Andrews, Mark P.; Juma, Salim K.; Chrostowski, Jacek; Najafi, S. Iraj

    1997-01-01

    We report on the fabrication and characterization of waveguide thin films on silicon by ultraviolet light imprinting in a new photosensitive, organically modified aluminophosphate sol-gel silica glass prepared by a one-step dip-coating process. Appropriate combinations of ultraviolet light exposure time, sol-gel film thickness and postbake parameters produce waveguides suitable for optical telecommunication applications.

  5. Fiber-Optic Temperature Sensor Using a Thin-Film Fabry-Perot Interferometer

    NASA Technical Reports Server (NTRS)

    Beheim, Glenn

    1997-01-01

    A fiber-optic temperature sensor was developed that is rugged, compact, stable, and can be inexpensively fabricated. This thin-film interferometric temperature sensor was shown to be capable of providing a +/- 2 C accuracy over the range of -55 to 275 C, throughout a 5000 hr operating life. A temperature-sensitive thin-film Fabry-Perot interferometer can be deposited directly onto the end of a multimode optical fiber. This batch-fabricatable sensor can be manufactured at a much lower cost than can a presently available sensor, which requires the mechanical attachment of a Fabry-Perot interferometer to a fiber. The principal disadvantage of the thin-film sensor is its inherent instability, due to the low processing temperatures that must be used to prevent degradation of the optical fiber's buffer coating. The design of the stable thin-film temperature sensor considered the potential sources of both short and long term drifts. The temperature- sensitive Fabry-Perot interferometer was a silicon film with a thickness of approx. 2 microns. A laser-annealing process was developed which crystallized the silicon film without damaging the optical fiber. The silicon film was encapsulated with a thin layer of Si3N4 over coated with aluminum. Crystallization of the silicon and its encapsulation with a highly stable, impermeable thin-film structure were essential steps in producing a sensor with the required long-term stability.

  6. Optical properties of multilayer bimetallic films obtained by laser deposition of colloidal particles

    NASA Astrophysics Data System (ADS)

    Antipov, A.; Arakelian, S.; Vartanyan, T.; Gerke, M.; Istratov, A.; Kutrovskaya, S.; Kucherik, A.; Osipov, A.

    2016-11-01

    The optical properties of multilayer bimetallic films composed of silver and gold nanoparticles have been investigated. The dependence of the transmission spectra of the films on their morphology is demonstrated. A finite-difference time-domain (FDTD) simulation has confirmed that there is a dependence of the transmission spectra on the average distance between particles and the number of deposited layers.

  7. Conformal self-assembled thin films for optical pH sensors

    NASA Astrophysics Data System (ADS)

    Topasna, Daniela M.; Topasna, Gregory A.; Liu, Minghanbo; Tseng, Ching-Hung

    2016-04-01

    Simple, reliable, lightweight, and inexpensive thin films based sensors are still in intense development and high demand in many applications such as biomedical, industrial, environmental, military, and consumer products. One important class of sensors is the optical pH sensor. In addition, conformal thin film based sensors extend the range of application for pH optical sensors. We present the results on the fabrication and characterization of optical pH sensing coatings made through ionic self-assembled technique. These thin films are based on the combination of a polyelectrolyte and water-soluble organic dye molecule Direct Yellow 4. A series of films was fabricated and characterized in order to determine the optimized parameters of the polymer and of the organic dye solutions. The optical pH responses of these films were also studied. The transparent films were immersed in solutions at various temperature and pH values. The films are stable when immersed in solutions with pH below 9.0 and temperatures below 90 °C and they maintain their performance after longer immersion times. We also demonstrate the functionality of these coatings as conformal films.

  8. Study of optical and mechanical strengths of the glass composites with sol-gel films

    NASA Astrophysics Data System (ADS)

    Atkarskaya, A. B.; Zakalova, E. Yu; Kaunov, V. S.; Nartzev, V. M.; Chartiy, P. V.; Shemanin, V. G.

    2016-11-01

    Dependences of optical and mechanical strengths of glass composites with the drawn films upon the film thickness, particles packing density in a layer in the sol disperse phase and the particles diameter have been studied experimentally. We report that the laser ablation threshold energy density values decrease with the growth of the composites microhardness.

  9. Optical chloride sensor based on dimer-monomer equilibrium of indium(III) octaethylporphyrin in polymeric film.

    PubMed

    Zhang, Wei; Rozniecka, Ewa; Malinowska, Elzbieta; Parzuchowski, Pawel; Meyerhoff, Mark E

    2002-09-01

    A novel transduction chemistry for preparing optical anion-selective polymeric films that respond reversibly and selectively to chloride ion activity is demonstrated. The chloride sensors are prepared by casting thin (5-10 microm) plasticized PVC films containing indium(III) octaethylporphyrin hydroxide, along with optimized levels of a lipophilic tetraphenylborate salt, onto glass slides. When bathed in low-pH buffered solutions void of chloride, the porphyrin species spontaneously forms a hydroxide ion-bridged dimer, with the added lipophilic borate species serving as the counteranion for this complex. The maximum for the Soret absorption band of this dimeric species is shifted to 390 nm, from 410 nm for the initial monomeric porphyrin. Increases in chloride ion levels in the bathing solution results in chloride extraction and ligation to the In(III) center, and concomitant breaking of the dimer into monomeric porphyrin species, yielding a decrease in absorbance at 390 nm and an increase in optical signal at 410 nm. Under optimized conditions, optical selectivity coefficients toward chloride over a wide range of other anions (NO3-, ClO4-, SCN-, SO4(2-), F-, Br-, H2PO4-) are measured to be < 10(-3). Of all anions tested, only salicylate yields a slightly greater response than chloride. This selectivity is shown to be adequate for reversible and accurate sensing of chloride levels in diluted serum samples.

  10. Characterization of Cd1- x Mg x Te film and plasma diagnostic studies by optical emission spectroscopy during sputtering

    NASA Astrophysics Data System (ADS)

    Gupta, S.; Compaan, A. D.

    2009-06-01

    Cd1- x Mg x Te is an attractive II-VI semiconductor alloy candidate for obtaining energy gaps wider than 1.5 eV of CdTe needed for the top junction absorber layer in a polycrystalline thin-film tandem solar cell. We have shown that these alloy films can easily be prepared by sputtering, however, the sputtering rate is substantially lower than for CdTe and the attainable cell performance has been poor, both before and after activation treatments with chlorine-containing vapors. In this work we have applied optical emission spectroscopy (OES) using selected peaks of ArII, CdII, MgI, TeII and correlated the results with crystallographic and morphological characteristics of the deposited films. Results were obtained as a function of rf sputter power and sputter gas pressure.

  11. Investigation of structural and optical properties of solid solution films in PbF2-YF3 system

    NASA Astrophysics Data System (ADS)

    Tropin, A. N.

    2017-05-01

    This work deals with the physical chemistry of metal fluorides and their thin films applicable in thin-film optics and is related to the investigation of the structural and optical properties of solid solution films in the system PbF2-YF3 for the creation of interference coatings for the near- and mid-infrared spectra.

  12. Optical band gap tuning of Sb-Se thin films for xerographic based applications

    NASA Astrophysics Data System (ADS)

    Kaur, Ramandeep; Singh, Palwinder; Singh, Kulwinder; Kumar, Akshay; Thakur, Anup

    2016-10-01

    In the present paper we have studied the effect of Sb addition on the optical band gap tuning of thermally evaporated SbxSe100-x (x = 0, 5, 20, 50 and 60) thin films. The structural investigations revealed that all thin films were amorphous in nature. Transmission spectrum was taken in the range 400-2500 nm shows that all films are highly transparent in the near infrared region. The fundamental absorption edge shifts towards longer wavelength with Sb incorporation. The optical band gap decreases with addition of antimony in a-Se thin films. A good correlation has been drawn between experimentally estimated and theoretically calculated optical band gap. The decrease in optical band gap of thin films has been explained using chemical bond approach and density of states model. Decrease in optical band gap with Sb addition increases the concentration of electron deep traps which increases the X-ray sensitivity of Sb-Se thin films. Thus by tuning the optical band gap of Sb-Se alloy, it could be utilized for xerographic based applications.

  13. Improvement of optical properties of TiO2 thin film treated with electron beam.

    PubMed

    Shin, Joong-Hyeok; Lee, Byung Cheol; Woo, Hee-Gweon; Hwang, Kwang Ha; Jun, Jin

    2013-03-01

    Nanocrystalline titanium dioxide (TiO2) thin films on silicon wafer substrates were prepared by sol-gel spin coating process. The prepared thin films were treated with electron beam (1.1 MeV, 300 kGy) at air atmosphere. The effects of electron-beam (EB) irradiation on the structural and optical properties of the TiO2 thin films were investigated. The structures of all the TiO2 thin films by XRD analysis showed an anatase phase, and the phase remained unchanged within the investigating range of EB treatment. The thickness of the titania thin film decreased slightly with EB treatment whereas the porosity increased. The EB treatment of TiO2 thin film can increase the proportion of Ti3+ in Ti2p at the thin film surface. The optical transmittance of the film in the wavelength ranges of above 380 nm increased after the EB treatment while its refractive index decreased with increasing EB dose. Therefore, improvement of the optical properties could be due to the change in both surface chemistry and morphology of the TiO2 thin films affected by EB irradiation.

  14. Investigations in structural morphological and optical properties of Bi-Pb-S system thin films

    NASA Astrophysics Data System (ADS)

    Malika, Boukhalfa; Noureddine, Benramdane; Mourad, Medles; Abdelkader, Outzourhit; Attouya, Bouzidi; Hind, Tabet-derraz

    Bi2S3, PbS and Bi-Pb-S system thin films were grown on glass substrates by the spray pyrolysis technique. The films growth was realized by the reaction of aqueous solutions of bismuth trichloride (BiCl3) and trihydrate Lead Acetate (TLA) (Pb(CH3COO)2.3H2O) with thiourea on heated substrates. The films study was performed as a function of the TLA volume ratio (TLA vol. ratio) in the solution obtained by the mixture of BiCl3 and thiourea used as precursor solution (PrS). X-ray diffraction (XRD), field emitting scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) were used for structural and compositional analysis of the as deposited films. With the structural investigations, Bi2S3, PbS thin films and PbS-Bi2S3 composite thin films formation was confirmed. Optical properties of the deposited films were obtained using transmittance and reflectance measurements in the wavelength range [200-2500 nm]. The absorption edge shows a shift towards low energy with the increase of the TLA vol. ratio.The optical bandgaps for the films with various TLA vol. ratio are found to lie between those of the Bi2S3 and PbS ones. The optical parameters (extinction coefficient, refractive index, real and imaginary parts if the complex dielectric constant) of the thin films are also investigated. These are found to be dependent on the TLA vol. ratio.

  15. Optical and Thermo-optical Properties of Polyimide-Single-Walled Carbon Nanotube Films: Experimental Results and Empirical Equations

    NASA Technical Reports Server (NTRS)

    Smith, Joseph G., Jr.; Connell, John W.; Watson, Kent A.; Danehy, Paul M.

    2005-01-01

    The incorporation of single-walled carbon nanotubes (SWNTs) into the bulk of space environmentally durable polymers at loading levels greater than or equal to 0.05 wt % has afforded thin films with surface and volume resistivities sufficient for electrostatic charge mitigation. However, the optical transparency at 500 nm decreased and the thermo-optical properties (solar absorptivity and thermal emissivity) increased with increaed SWNT loading. These properties were also dependent on film thickness. The absorbance characteristics of the films as a function of SWNT loading and film thickness were measured and determined to follow the classical Beer-Lambert law. Based on these results, an empirical relationship was derived and molar absorptivities determined for both the SWNTs and polymer matrix to provide a predictive approximation of these properties. The molar absorptivity determined for SWNTs dispersed in the polymer was comparable to reported solution determined values for HiPco SWNTs.

  16. Thermo-optic coefficient of polyisobutylene ultrathin films measured with integrated photonic devices.

    PubMed

    Choi, Hong Seok; Neiroukh, Dania; Hunt, Heather K; Armani, Andrea M

    2012-01-10

    The optical properties of polymeric materials, such as transmission loss and the thermo-optic coefficient, determine their utility in numerous applications, ranging from nanotechnology to the automotive and aerospace industries. However, because of the wide variation in the physical properties of polymers, many are unsuited for characterization using conventional techniques; consequently, their optical properties are unknown. One such polymer is polyisobutylene, which is viscous at room temperature and therefore is not compatible with conventional transmission loss and the thermo-optic coefficient characterization techniques because they rely on contact measurements. To overcome this, we have developed an integrated, microscale optical sensor that relies on an evanescent wave to study the material's optical behavior. Using this device, we successfully determined the refractive index, the transmission loss, and the thermo-optic coefficient of ultrathin films of polyisobutylene. The films are deposited on the sensor's silica surface using either spin coating or surface-initiated cationic polymerization, demonstrating the flexibility of this approach.

  17. SODI-COLLOID (Selectable Optical Diagnostics Instrument - Colloid)

    NASA Image and Video Library

    2011-10-17

    ISS029-E-027431 (17 Oct. 2011) --- In the International Space Station?s Destiny laboratory, Japan Aerospace Exploration Agency astronaut Satoshi Furukawa, Expedition 29 flight engineer, activates the Microgravity Science Glovebox (MSG) in preparation for work with the Selectable Optical Diagnostics Instrument ? Colloid (SODI-COLLOID) hardware.

  18. SODI-COLLOID (Selectable Optical Diagnostics Instrument - Colloid)

    NASA Image and Video Library

    2011-10-17

    ISS029-E-027435 (17 Oct. 2011) --- In the International Space Station?s Destiny laboratory, Japan Aerospace Exploration Agency astronaut Satoshi Furukawa, Expedition 29 flight engineer, activates the Microgravity Science Glovebox (MSG) in preparation for work with the Selectable Optical Diagnostics Instrument ? Colloid (SODI-COLLOID) hardware.

  19. Synthesis and characterization of sol gel silica films doped with size-selected gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Ferrara, M. C.; Mirenghi, L.; Mevoli, A.; Tapfer, L.

    2008-09-01

    Homogeneous nanocomposite silica films uniformly doped with size-selected gold nanoparticles (AuNPs) have been prepared by a combined use of colloidal chemistry and the sol-gel process. For this purpose, stable thiol-functionalized AuNPs (DDT-AuNPs) were first synthesized by a two-phase aqueous/organic system and, subsequently, dispersed in an acid-catalysed sol-gel silica solution. The microstructural morphology of the samples was investigated by x-ray diffraction and field emission scanning electron microscopy. X-ray photoelectron spectroscopy (XPS) and UV-vis optical spectrophotometry were instead employed to investigate the elemental chemical behaviour and the evolution of the surface plasmon resonance (SPR) band of the AuNPs from their synthesis up to the formation of the Au-doped silica films. The results show that the size, shape and crystalline domains of the AuNPs remain unchanged during the entire preparation process, indicating that their aggregation or decomposition was prevented. XPS results show that the DDT-AuNPs lose the capping shells and oxidize themselves when dispersed in acid-catalysed sol-gel solutions, and that bare AuNPs are embedded in the SiO2 films. A large broadening of the SPR band, observed for systems with DDT-AuNPs, suggests the presence of interface effects which cause a surface electron density lowering. Thiol chain detachment from the AuNPs determines an increase of the SPR peak intensity while the oxidation of the Au surfaces causes a red shift of its position. The latter is no longer observed in doped films, suggesting that no interfacial effects between bare AuNPs and the host medium are present.

  20. Optical and mechanical properties of nanocrystalline ZrC thin films grown by pulsed laser deposition.

    DOE PAGES

    Craciun, D.; Socol, G.; Lambers, E.; ...

    2015-01-17

    Thin ZrC films (<500 nm) were grown on (100) Si substrates at a substrate temperature of 500 °C by the pulsed laser deposition (PLD) technique using a KrF excimer laser under different CH4 pressures. Glancing incidence X-ray diffraction showed that films were nanocrystalline, while X-ray reflectivity studies found out films were very dense and exhibited a smooth surface morphology. Optical spectroscopy data shows that the films have high reflectivity (>90%) in the infrared region, characteristic of metallic behavior. Nanoindentation results indicated that films deposited under lower CH4 pressures exhibited slightly higher nanohardness and Young modulus values than films deposited undermore » higher pressures. As a result, tribological characterization revealed that these films exhibited relatively high wear resistance and steady-state friction coefficients on the order of μ = 0.4.« less

  1. Optical and mechanical properties of nanocrystalline ZrC thin films grown by pulsed laser deposition.

    SciTech Connect

    Craciun, D.; Socol, G.; Lambers, E.; McCumiskey, E. J.; Taylor, C. R.; Martin, C.; Argibay, Nicolas; Craciun, V.; Tanner, D. B.

    2015-01-17

    Thin ZrC films (<500 nm) were grown on (100) Si substrates at a substrate temperature of 500 °C by the pulsed laser deposition (PLD) technique using a KrF excimer laser under different CH4 pressures. Glancing incidence X-ray diffraction showed that films were nanocrystalline, while X-ray reflectivity studies found out films were very dense and exhibited a smooth surface morphology. Optical spectroscopy data shows that the films have high reflectivity (>90%) in the infrared region, characteristic of metallic behavior. Nanoindentation results indicated that films deposited under lower CH4 pressures exhibited slightly higher nanohardness and Young modulus values than films deposited under higher pressures. As a result, tribological characterization revealed that these films exhibited relatively high wear resistance and steady-state friction coefficients on the order of μ = 0.4.

  2. Optically anisotropic microlens array film directly formed on a single substrate.

    PubMed

    Ren, Hongwen; Xu, Su; Liu, Yifan; Wu, Shin-Tson

    2013-12-02

    An optically anisotropic microlens array film directly formed on a single substrate is demonstrated. UV curable diacrylate monomers are coated as a film on the substrate. Under the action of fringing field, not only the film surface is flattened by the generated dielectric force but also the monomers are reoriented to form a gradient refractive index (GRIN) distribution in the film. Via UV exposure, the GRIN distribution is fixed and the polymeric film behaves as a microlens array. The fabrication process is simple and the film offers a switchable focus through controlling the polarization direction of the incident light. Integrating with a 90° twisted-nematic liquid crystal cell, our polymeric microlens array film shows great potential for switchable 2D/3D autostereoscopic displays.

  3. High-performance transparent film heater with an embedded Ni metal-mesh based on selected metal electrodeposition process

    NASA Astrophysics Data System (ADS)

    Liu, Yanhua; Shen, Su; Chen, LinSen; Zhou, Yun; Ye, Yan; Wang, Yanyan; Qiao, Wen; Huang, Wenbin

    2016-10-01

    An ultra-flexible and low-sheet resistance transparent conductive film is developed from nickel metal-mesh (Ni metal-mesh) embedded in a polyimide (PI) by exploiting selective deposition technique coupled with photolithography and subsequent inverted film-processing method. The fabricated conductive film achieved sheet resistance values as low as 0.15 Ω sq-1, with corresponding optical transmittance as 80% at 550 nm corresponding the figure of merit up to 1.1×104. The film shows excellent adhesion and also preserves its structural integrity and good contact with the substrate for severe bending showing less than 4% decrease of conductivity even after 104 cycles. Finally, employing the fabricated Ni metal-mesh/PI conductive film, a hybrid transparent thin-film heater is demonstrated, which exhibited higher heating temperatures (110°C) under the lower operating voltage (1 V), lower power consumption (79.1°C cm2 W-1), and shorter response time (T < 2 s) than other heaters, as well as stability after repeated test.

  4. Structural, optical and electrical properties of V2O5 xerogel thin films

    NASA Astrophysics Data System (ADS)

    Bera, B.; Esther, A. C. M.; Dey, A.; Mukhopadhyay, A. K.

    2016-06-01

    In the present work V2O5 xerogel thin films are deposited on quartz substrate by using a cost effective sol-gel based dip coating method. Films of thickness 122, 224 and 284 nm are grown as the number of dipping varies from one to three. Phase analyses of the thin films are investigated by X-ray diffraction technique. The microstructural characterization is carried out by electron microscopy techniques. Crystalline, phase pure V2O5 thin films with uniform nanoporous microstructure are grown in the present work. Solar transmittance and reflectance of films are measured by UV-VIS-NIR spectrophotometer. The optical band gap, refractive index and extinction coefficient of the films are also evaluated. Further, the average solar absorptance and IR emittance are evaluated by solar spectrum reflectometer and emissometer, respectively. The solar transmittance and optical band gap decrease with the increase in film thickness from 122 to 284 nm while reverse trend is observed for solar absorptance. Refractive index ( 1.95) and IR emittance ( 0.75) of the nanoporous V2O5 xerogel thin films on quartz substrate are almost independent of film thickness. The sheet resistance value slightly decreases from 1.6 × 106 to 2.6 × 105 ohm/cm2 as the thickness of the V2O5 xerogel thin film increases from 112 to 284 nm.

  5. Structural, Optical and Electrical Properties of Sol-Gel Derived Titanium Dioxide Thin Film

    NASA Astrophysics Data System (ADS)

    Taşkin, Dilek; Dumludaǧ, Fatih; Altindal, Ahmet

    2007-04-01

    Optical, structural and electrical (dc and ac) properties of sol-gel derived TiO2 film in a wide range of temperature (290 - 652 K) were investigated. XRD analysis was used for investigation the crystallinity of the films. Optical bad gap of the film were determined from transmission spectra. With the examination of the impedance spectra clear differences could be seen in the dependence of ω on both real and imaginary part of impedance between 290 K and 652 K. The impedance response is significantly changed with the increase of temperature.

  6. Structure and Optical Properties of Nanocrystalline Hafnium Oxide Thin Films (PostPrint)

    DTIC Science & Technology

    2014-09-01

    AFRL-RX-WP-JA-2014-0214 STRUCTURE AND OPTICAL PROPERTIES OF NANOCRYSTALLINE HAFNIUM OXIDE THIN FILMS (POSTPRINT) Neil R. Murphy AFRL...OPTICAL PROPERTIES OF NANOCRYSTALLINE HAFNIUM OXIDE THIN FILMS (POSTPRINT) 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...publication is available at http://dx.doi.org/10.1016/j.optmat.2014.08.005 14. ABSTRACT Hafnium oxide (HfO2) films were grown by sputter-deposition by

  7. Light irradiation tuning of surface wettability, optical, and electric properties of graphene oxide thin films

    NASA Astrophysics Data System (ADS)

    Furio, A.; Landi, G.; Altavilla, C.; Sofia, D.; Iannace, S.; Sorrentino, A.; Neitzert, H. C.

    2017-02-01

    In this work the preparation of flexible polymeric films with controlled electrical conductivity, light transmission and surface wettability is reported. A drop casted graphene oxide thin film is photo-reduced at different levels by UV light or laser irradiation. Optical microscopy, IR spectroscopy, electrical characterization, Raman spectroscopy and static water contact angle measurements are used in order to characterize the effects of the various reduction methods. Correlations between the optical, electrical and structural properties are reported and compared to previous literature results. These correlations provide a useful tool for independently tuning the properties of these films for specific applications.

  8. Structural and optical properties of electron beam evaporated yttria stabilized zirconia thin films

    SciTech Connect

    Kirubaharan, A. Kamalan; Kuppusami, P. Dharini, T.; Ramachandran, D.; Singh, Akash; Mohandas, E.

    2015-06-24

    Yttria stabilized zirconia (10 mole % Y{sub 2}O{sub 3}) thin films were deposited on quartz substrates using electron beam physical vapor deposition at the substrate temperatures in the range 300 – 973 K. XRD analysis showed cubic crystalline phase of YSZ films with preferred orientation along (111). The surface roughness was found to increase with the increase of deposition temperatures. The optical band gap of ∼5.7 eV was calculated from transmittance curves. The variation in the optical properties is correlated with the changes in the microstructural features of the films prepared as a function of substrate temperature.

  9. DNA based thin solid films and its application to optical fiber temperature sensor

    NASA Astrophysics Data System (ADS)

    Hong, Seongjin; Jung, Woohyun; Kim, Taeoh; Oh, Kyunghwan

    2017-04-01

    Temperature dependent refractive index of DNA-cetyltrimethylammonium chloride (CTMA) thin-solid-film was measured 20 to 90° to obtain its thermo-optic coefficient of -3.6×10-4 (dn/dT). DNA- CTMA film has high thermosoptic coefficient than other polymers. The film was deposited on coreless silica fiber (CSF) to serve as a multimode interferometer optical fiber temperature sensor. It is immersed in a water that changed temperature from 40 to 90°. It has sensitivity of 0.25nm/℃.

  10. Nonlinear optical properties of ZnO/poly (vinyl alcohol) nanocomposite films

    SciTech Connect

    Jeeju, P. P.; Jayalekshmi, S.; Chandrasekharan, K.

    2014-01-28

    Extensive studies have already been reported on the optical characteristics of ZnO/polymer nanocomposite films, using a variety of polymers including transparent polymers such as polystyrene, polymethyl methacrylate etc and many interesting results have been established regarding the non linear optical characteristics of these systems. Poly (vinyl alcohol)(PVA) is a water soluble polymer. Though the structural and optical studies of ZnO/PVA nanocomposite films have already been investigated, there are no detailed reports on the nonlinear optical characteristics of ZnO/PVA nanocomposite films, irrespective of the fact that these nanocomposite films can be synthesized using quite easy and cost effective methods. The present work is an attempt to study in detail the nonlinear optical behaviour of ZnO/PVA nanocomposite films using Z-scan technique. Highly transparent ZnO/PVA nanocomposite films were prepared from the ZnO incorporated PVA solution in water using spin coating technique. The ZnO nanoparticles were synthesized by the simple chemical route at room temperature. High-resolution transmission electron microscopy studies show that the ZnO nanoparticles are of size around 10 nm. The ZnO/PVA nanocomposite films were structurally characterized by X-ray diffraction technique, from which the presence of both PVA and ZnO in the nanocomposite was established. The optical absorptive nonlinearity in the nanocomposite films was investigated using open aperture Z-scan technique. The results indicate optical limiting type nonlinearity in the films due to two photon absorption in ZnO with efficiency more than 50%. These films also show a self defocusing type negative nonlinear refraction in closed aperture Z-scan experiment. The present studies indicate that, highly transparent and homogeneous films of ZnO/PVA nanocomposite can be obtained on glass substrates using simple methods, in a highly cost effective way, since PVA is water soluble. These nanocomposite films offer

  11. Ultrafast optical response of the Au-BaO thin film stimulated by femtosecond pulse laser

    NASA Astrophysics Data System (ADS)

    Wu, J. L.; Wang, C. M.; Zhang, G. M.

    1998-06-01

    The pump-probe method was applied to study the dependence of the transient optical transmissivity upon time delay for the Au-BaO composite thin film stimulated by a femtosecond pulsed laser. It was observed that the light absorption of the thin film increased rapidly and then resumed its initial value in several picoseconds. Optical relaxation is a process in which nonequilibrium electrons, excited by laser pulses and originating from Au ultrafine particles, return to the equilibrium state. In this article, the value of the electron-phonon coupling constant g of gold ultrafine particles in the composite thin film was calculated theoretically.

  12. Optical+NIR Quasar Selection with the SDSS and UKIDSS

    NASA Astrophysics Data System (ADS)

    Mehta, Sajjan S.; Mahon, R. G.; Richards, G. T.; Hewett, P. C.

    2010-01-01

    We present the details of an optical+near-IR quasar selection technique, which utilizes near-IR data from the UKIDSS Large Area Survey and the optical data from the Sloan Digital Sky Survey in the SDSS's deep "Stripe 82" region, which covers over 200 deg2. Our selection methods primarily consist of isolating potential candidates in giK and gJK color space, in which there exists a significant separation of the stellar locus from the quasar locus. Additionally, we discuss secondary techniques such as comparison of catalog magnitudes with aperture photometry, analysis of SDSS and UKIDSS morphological type classifications, and flag cuts. Our primary color-cut selections include most quasars with redshifts below 3.4, significantly increasing the completeness both to dust reddened quasars and quasars with redshifts z 2.7 in the SDSS footprint. A simple color cut in the UKIDSS LAS Stripe 82 regions reveals 4200 quasar candidates down to K=18. These NIR selections have been used to contribute to the Baryon Oscillation Spectroscopic Survey (BOSS), which is one of the four surveys of the SDSS-III collaboration. We additionally intend to use our NIR techniques to perform an 8-dimensional optical+NIR Bayesian selection of quasars for the AAOmege UKIDSS SDSS (AUS) survey.

  13. All-photonic switching based on selective input pump polarization states in Fe-doped PbS/PVA freestanding nanocomposite films

    NASA Astrophysics Data System (ADS)

    Rahma, M. A.; Saadon, H. L.; Mahdi, M. A.

    2017-04-01

    A new optical pump–probe technique for all-optical switching is proposed based on three-selective input pump polarization states to pump material simultaneously. The new technique makes it possible to obtain efficient all-optical switching of nonlinear optical materials with very low signal background and increased stability of switching signals. Undoped and Fe-doped PbS/PVA freestanding nanocomposite films are prepared by a simple chemical method at different doping concentrations. The x-ray diffraction patterns and optical absorption spectra of the prepared films are examined. The crystallinity and optical band gap of the prepared Fe-PbS/PVA are found to be affected by Fe doping concentration. The all-optical switching effect of Fe-PbS/PVA freestanding nanocomposite films with various Fe concentrations was investigated. The proposed technique that demonstrates all-optical switching with three-input polarization states can lead to the realization of all-photonic switching at a threshold optical pump power of 19 mW with maximum modulation depth (ON/OFF) of 86% and switching contrast (ON/OFF) of 8.6 dB for a minimum switching time of 43 ms.

  14. Optical and structural properties of PbI2 thin film produced via chemical dipping method

    NASA Astrophysics Data System (ADS)

    Kariper, İ. A.

    2016-06-01

    PbI2 thin films were deposited on glass substrates via chemical bath deposition. The characteristics of PbI2 thin films were examined through their structural and optical properties. X-ray diffraction spectra showed the presence of rhombohedral structure and atom planes were subject to change with the pH of the bath. Scanning electron microscope indicated uniform distribution of grains. Optical properties were examined via UV-VIS; optical spectrum of the thin films was measured at the range of 200-1100 nm wavelength. Optimum pH levels for producing thin films were found to be pH 4-5. It has been observed that transmission and optical band gap ( E g) increased with the pH of the bath, which varied between 66-95 and 2.24-2.50 %, respectively; on the other hand film thickness of PbI2 thin films was decreased with the pH of the bath. Energy-dispersive X-ray spectroscopy analysis were in accordance with theoretical value of PbI2 at pH = 4 and 5. Refractive index was negatively correlated with pH of the chemical bath; it has been calculated as 1.97, 1.40, 1.29 and 1.24 for the films produced at pH 2, 3, 4 and 5. The results of the study were compared with similar studies in the literature.

  15. Changes in chemical and optical properties of thin film metal mirrors on LDEF

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Zwiener, James M.; Gregory, John C.; Raikar, Ganesh N.; Christl, Ligia C.; Wilkes, Donald R.

    1995-01-01

    Thin films of the metals Cu, Ni, Pt, Au, Sn, Mo, and W deposited on fused silica flats were exposed at ambient temperature on the leading and trailing faces of the LDEF. Reflectances of these films were measured from 250 to 2500 nm and compared with controls. The exposed films were subjected to the LDEF external environment including atomic oxygen, molecular contamination, and solar ultraviolet. Major changes in optical and infrared reflectance were seen for Cu, Mo, Ni, and W films on the leading face of LDEF and are attributed to partial conversion of metal to metal oxide. Smaller changes in optical properties are seen on all films and are probably caused by thin contaminant films deposited on top of the metal. The optical measurements are correlated with film thickness measurements, x-ray photoelectron spectroscopy, optical calculations, and, in the case of Cu, with x-ray diffraction measurements. In a few cases, comparisons with results from a similar UAH experiment on STS-8 have been drawn.

  16. Photoresponsive behavior and switchable nonlinear optical properties of Langmuir-Blodgett film based on azobenzene derivatives.

    PubMed

    Li, Qiuyue; Chi, Zhen; Li, Tianfeng; Ran, Xia; Guo, Lijun

    2017-05-15

    Here, we present the investigations of photo-isomerization behavior and the nonlinear optical properties of azobenzene derivative LB films. The few-layer LB films of AOB-t4 and BNB-t4 exhibit positive nonlinear refraction and two-photon absorption properties as revealed by picosecond Z-scan. The increased conjugation by introducing an oxadiazole group improves the photo-isomerization rate and the nonlinear optical properties, due to a weaker intermolecular interaction and the formation of J-aggregates within AOB-t4 LB film. The third-order susceptibility of cis-AOB-t4 9-layer LB film reaches 1.866 × 10(-9) esu and the two-photon absorption coefficient is on the order of 10(-8) m/W. Interestingly, the 15-layer AOB-t4 LB film shows negative nonlinear refraction and saturable absorption. Taken together, we have demonstrated the switchable nonlinear optical absorption and refraction properties of AOB-t4 LB film with changing film thickness, which is of significance for nonlinear optics and photonics applications.

  17. The effect of FeCl 3 on the optical constants and optical band gap of MBZMA- co-MMA polymer thin films

    NASA Astrophysics Data System (ADS)

    Yakuphanoglu, F.; Barım, G.; Erol, I.

    2007-03-01

    The effects of the FeCl 3 dopant on the optical constants and optical band gap of the methylbenzyl methacrylate (MBZMA)- co-methyl-methacrylate (MMA) polymer thin films have been investigated by the optical characterization. The optical constants of the thin films are changed with FeCl 3 dopant. The refractive index dispersion curves of the thin films are fitted by Cauchy-Sellmeier model and dispersion parameters ( a1 and n0) change with FeCl 3 dopant. The magnitude of the refractive index increases with increasing FeCl 3 dopant. The electric susceptibility of the thin film materials was calculated and the electric susceptibility increases with FeCl 3 content. The optical band gap values of the thin films were determined. The obtained band gap values are decreased with FeCl 3 dopant. The FeCl 3 dopant changes the width of localized states in the optical band gaps of the thin films. The optical band Eg of the thin films changes from 3.52 to 3.05 eV with increasing FeCl 3 dopant, while the width of localized states in optical band gap changes from 1101.47 to 596.3 meV. It is concluded that the optical constants and optical band gap of the MBZMA- co-MMA polymer thin films change by the FeCl 3 dopant.

  18. Thickness and microstructure effects in the optical and electrical properties of silver thin films

    SciTech Connect

    Ding, Guowen Clavero, César; Schweigert, Daniel; Le, Minh

    2015-11-15

    The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C), with a value of 59 ± 2 μΩ cm ⋅ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

  19. Effect of Se addition on optical and electrical properties of chalcogenide CdSSe thin films

    NASA Astrophysics Data System (ADS)

    Hassanien, A. S.; Akl, Alaa A.

    2016-01-01

    Compositional dependence of optical and electrical properties of chalcogenide CdSxSe1-x (0.4 ≥ x ≥ 0.0 at. %) thin films was studied. Cadmium sulphoselenide films were deposited by thermal evaporation technique at vacuum (8.2 × 10-4 Pa) onto preheated glass substrates (523 K). The evaporation rate and film thickness were kept constant at 2.50 nm/s and 375 ± 5 nm, respectively. X-ray diffractograms showed that, the deposited films have the low crystalline nature. Energy dispersive analysis by X-ray (EDAX) was used to check the compositional elements of deposited films. The absorption coefficient was determined from transmission and reflection measurements at room temperature in the wavelength range 300-2500 nm. Optical density, skin depth, optical energy gap and Urbach's parameters of CdSSe thin films have also been estimated. The direct optical energy gap decreased from 2.248 eV to 1.749 eV when the ratio of Se-content was increased from 0.60 to 1.00 . Conduction band and valance band positions were evaluated. The temperature dependence of dc-electrical resistivity in the temperature range (293-450 K) has been reported. Three conduction regions due to different conduction mechanisms were detected. Electrical sheet resistance, activation energy and pre-exponential parameters were discussed. The estimated values of optical and electrical parameters were strongly dependent upon the Se-content in CdSSe matrix.

  20. A simple growth method for Nb2O5 films and their optical properties

    DOE PAGES

    Dash, J. K.; Chen, L.; Topka, Michael R.; ...

    2015-04-13

    A simple method for the synthesis of Nb₂O₅ films of thicknesses ranging from tens to several hundreds of nanometers on amorphous silicon dioxide or quartz substrates is presented. Nb₂O₅ films were formed by annealing the sputter deposited Nb films under an Ar flow and without oxygen plasma in a quartz tube within a furnace at 850 °C. The structural, compositional, optical, and vibrational properties were characterized by grazing incidence X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet visible spectroscopy, and Raman scattering. Each of the Nb₂O₅ films is polycrystalline with an orthorhombic crystal structure. We observed vibrational modes includingmore » longitudinal optical, transverse optical, and triply degenerate modes, and measured the indirect optical band gap to be ~3.65 eV. The transmittance spectrum of the ~20 nm thick Nb₂O₅ film shows over 90% transmittance below the band gap energy in the visible wavelength range and decreases to less than 20% in the ultraviolet regime. As a result, the optical properties of the films in the UV-vis range show potential applications as UV detectors.« less

  1. Microscopic thin film optical anisotropy imaging at the solid-liquid interface.

    PubMed

    Miranda, Adelaide; De Beule, Pieter A A

    2016-04-01

    Optical anisotropy of thin films has been widely investigated through ellipsometry, whereby typically an optical signal is averaged over a ∼1 cm(2) elliptical area that extends with increasing angle-of-incidence (AOI). Here, we report on spectroscopic imaging ellipsometry at the solid-liquid interface applied to a supported lipid bilayer (SLB). We detail how a differential spectrally resolved ellipsometry measurement, between samples with and without optically anisotropic thin film on an absorbing substrate, can be applied to recover in and out of plane refractive indices of the thin film with known film thickness, hence determining the thin film optical anisotropy. We also present how optimal wavelength and AOI settings can be determined ensuring low parameter cross correlation between the refractive indices to be determined from a differential measurement in Δ ellipsometry angle. Furthermore, we detail a Monte Carlo type analysis that allows one to determine the minimal required optical ellipsometry resolution to recover a given thin film anisotropy. We conclude by presenting a new setup for a spectroscopic imaging ellipsometry based on fiber supercontinuum laser technology, multi-wavelength diode system, and an improved liquid cell design, delivering a 5 ×-10 × ellipsometric noise reduction over state-of-the-art. We attribute this improvement to increased ellipsometer illumination power and a reduced light path in liquid through the use of a water dipping objective.

  2. Thickness and microstructure effects in the optical and electrical properties of silver thin films

    NASA Astrophysics Data System (ADS)

    Ding, Guowen; Clavero, César; Schweigert, Daniel; Le, Minh

    2015-11-01

    The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C), with a value of 59 ± 2 μΩ cm ṡ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

  3. Microscopic thin film optical anisotropy imaging at the solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Miranda, Adelaide; De Beule, Pieter A. A.

    2016-04-01

    Optical anisotropy of thin films has been widely investigated through ellipsometry, whereby typically an optical signal is averaged over a ˜1 cm2 elliptical area that extends with increasing angle-of-incidence (AOI). Here, we report on spectroscopic imaging ellipsometry at the solid-liquid interface applied to a supported lipid bilayer (SLB). We detail how a differential spectrally resolved ellipsometry measurement, between samples with and without optically anisotropic thin film on an absorbing substrate, can be applied to recover in and out of plane refractive indices of the thin film with known film thickness, hence determining the thin film optical anisotropy. We also present how optimal wavelength and AOI settings can be determined ensuring low parameter cross correlation between the refractive indices to be determined from a differential measurement in Δ ellipsometry angle. Furthermore, we detail a Monte Carlo type analysis that allows one to determine the minimal required optical ellipsometry resolution to recover a given thin film anisotropy. We conclude by presenting a new setup for a spectroscopic imaging ellipsometry based on fiber supercontinuum laser technology, multi-wavelength diode system, and an improved liquid cell design, delivering a 5 ×-10 × ellipsometric noise reduction over state-of-the-art. We attribute this improvement to increased ellipsometer illumination power and a reduced light path in liquid through the use of a water dipping objective.

  4. Water electrolysis-induced optical degradation of aluminum-doped zinc oxide films

    NASA Astrophysics Data System (ADS)

    Fang, Linggang; Fang, Guojia; Chen, Wanping; Li, Chun; Sheng, Su; Ma, Shuang; Zhao, Xingzhong

    2006-12-01

    A type of optical degradation of aluminium-doped zinc oxide (AZO) films due to water electrolysis-induced reduction reaction was reported. An experiment was designed in which AZO films were immersed in a 0.01 M NaOH aqueous solution as cathode to electrolyze water. Significant decreases in the optical transmission of the treated samples were observed. Studies by X-ray diffraction and scanning electron microscope showed that the degradation of AZO films was due to compositional and structural changes with the treatment of water electrolysis, which resulted from the reduction reaction of atomic hydrogen generated in the electrolysis of water. This optical degradation reflects the stability degradation of AZO films under water electrolysis environment.

  5. Correlation between composition, morphology and optical properties of PVK: n-ZnO:CTAB thin films

    NASA Astrophysics Data System (ADS)

    Azizi, Samir; Belhaj, Marwa; Zargouni, Sarra; Dridi, Cherif

    2017-07-01

    In this study, we report on the effect of zinc oxide nanoparticles ( n-ZnO) content and surfactant addition on the performance of poly ( N-vinylcarbazole) (PVK): n-ZnO nanocomposite thin films. Morphological and optical properties of ZnO, PVK and PVK: n-ZnO:cetyltrimethyl ammonium bromide (CTAB) hybrid films were investigated by atomic force microscopy (AFM), UV-Visible spectrophotometry and photoluminescence (PL) spectroscopy. We noticed that surface morphology was very dependent on surfactant addition into inorganic and organic components and on the ZnO content in the mixture. The optical absorption spectra of PVK: n-ZnO thin films showed a red shift of the optical band gap energy. Besides, PL measurements demonstrated an interfacial charge transfer between PVK matrix and ZnO nanoparticles through the reduced PL intensity of nanocomposites compared to PVK thin films.

  6. Optical Characterization of Multilayer Thin Film Cu_xIn_2-xSe_2^*

    NASA Astrophysics Data System (ADS)

    Raffaelle, R. P.; Friedfeld, R.; Mantovani, J. G.

    1996-03-01

    Cu_xIn_2-xSe2 is one of the most promising thin film solar cell materials, due to its ideal optical and electrical properties. We have been electrochemically depositing multilayer structures based on the Cu_xIn_2-xSe2 system. The interest in multilayer structures is due to their proposed use in increasing thin film solar cell efficiency. A comparison of the multilayers to ordinary bulk films is made using optical spectroscopy. The optical band gaps for these nanoscale layered films is determined as a function of their modulation wavelengths and compared to theoretical predictions. * This work was supported by the Southeastern University Research Association in collaboration with Oak Ridge National Laboratory and the Florida Solar Energy Center.

  7. Structural, Optical, and Electrical Characterization of Spray Pyrolysed Indium Sulfide Thin Films

    NASA Astrophysics Data System (ADS)

    Rahman, F.; Podder, J.; Ichimura, M.

    2013-03-01

    Indium sulfide (In2S3) thin films were deposited onto the glass substrates by a low cost simple spray pyrolysis technique at 300°C temperature. Aqueous solution of indium chloride and thiourea were used to deposit the binary In-S film. The deposited thin films were annealed at 400° and 500°C temperatures and characterized structurally, optically and electrically using EDX, X-ray diffraction, UV-visible spectroscopy and four probe van der Pauw methods. The optical constants such as refractive index and extinction coefficient are calculated from absorbance and transmittance data from 300 to 1100 nm wavelength. The optical transmittance increased after annealing at 400° and 500°C. The band gap energy was reduced from 2.90 to 2.50 eV after annealing the as deposited films. The electrical conductivity as well as the activation energy was increased after annealing the samples.

  8. Structural and optical characterization of WO{sub 3} thin films for gas sensor applications

    SciTech Connect

    Gyoergy, E.; Socol, G.; Mihailescu, I.N.; Ducu, C.; Ciuca, S.

    2005-05-01

    The structure, chemical composition, and optical properties of tungsten trioxide thin films grown by pulsed laser deposition were investigated. An ultraviolet KrF{sup *} excimer laser ({lambda}=248 nm, {tau}{sub FWHM} congruent with 20 ns, {nu}=2 Hz) was used for irradiation of tungsten trioxide targets in oxygen atmosphere. Our research focused on the effect of the ambient gas pressure and substrate temperature on the chemical composition, crystalline status, and optical properties of the obtained thin films. To this end, the films were studied by x-ray diffractometry Raman spectroscopy, and energy dispersive x-ray spectroscopy. Optical transmittance measurements were performed with a double beam spectrometer within the 400-1200 nm range. The films deposited at oxygen pressure values higher than 10 Pa and substrate temperatures above 300 deg. C consist of crystalline tungsten trioxide. Their average transmittance in the visible-infrared spectral region reaches about 85% appropriate for the envisaged applications.

  9. Interfaces roughness cross correlation properties and light scattering of optical thin films

    NASA Astrophysics Data System (ADS)

    Pan, Yong-qiang; Wu, Zhen-sen; Hang, Ling-xia

    2009-05-01

    In order to study optical thin films interfaces roughness cross correlation properties and light scattering, theoretical models of optical thin films interfaces roughness light scattering are concisely presented. Furthermore, influence of interfaces roughness cross-correlation properties to light scattering was analyzed by total backscattering. Moreover, TiO2 single optical films thickness, substrate roughness of K9 glass and ion beam assisted deposition (IBAD) technique effect on interface roughness cross correlation properties were studied by experiments, respectively. The results showed that theoretical results obtained by integrating vector light scattering were agreed well with experimental results. The interfaces roughness cross-correlation decrease with the increase of films thickness or with the decrease of substrates roughness. When ion beam assisted deposition was used, a high degree of cross-correlated can be obtained.

  10. Optical, dielectric and morphological studies of sol-gel derived nanocrystalline TiO2 films.

    PubMed

    Vishwas, M; Sharma, Sudhir Kumar; Narasimha Rao, K; Mohan, S; Gowda, K V Arjuna; Chakradhar, R P S

    2009-10-15

    Nanocrystalline TiO(2) films have been synthesized on glass and silicon substrates by sol-gel technique. The films have been characterized with optical reflectance/transmittance in the wavelength range 300-1000 nm and the optical constants (n, k) were estimated by using envelope technique as well as spectroscopic ellipsometry. Morphological studies have been carried out using atomic force microscope (AFM). Metal-Oxide-Silicon (MOS) capacitor was fabricated using conducting coating on TiO(2) film deposited on silicon. The C-V measurements show that the film annealed at 300 degrees C has a dielectric constant of 19.80. The high percentage of transmittance, low surface roughness and high dielectric constant suggests that it can be used as an efficient anti-reflection coating on silicon and other optical coating applications and also as a MOS capacitor.

  11. An optically transparent, flexible, patterned and conductive silk biopolymer film (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Umar, Muhammad; Min, Kyungtaek; Kim, Sunghwan

    2017-02-01

    Transparent, flexible, and conducting films are of great interest for wearable electronics. For better biotic/abiotic interface, the films to integrate the electronics components requires the patterned surface conductors with optical transparency, smoothness, good electrical conductivity, along with the biofriendly traits of films. We focus on silk fibroin, a natural biopolymer extracted from the Bombyx mori cocoons, for this bioelectronics applications. Here we report an optically transparent, flexible, and patterned surface conductor on a silk film by burying a silver nanowires (AgNW) network below the surface of the silk film. The conducting silk film reveals high optical transparency of 80% and the excellent electronic conductivity of 15 Ω/sq, along with smooth surface. The integration of light emitting diode (LED) chip on the patterned electrodes confirms that the current can flow through the transparent and patterned electrodes on the silk film, and this result shows an application for integration of functional electronic/opto-electronic devices. Additionally, we fabricate a transparent and flexible radio frequency (RF) antenna and resistor on a silk film and apply these as a food sensor by monitoring the increasing resistance by the flow of gases from the spoiled food.

  12. Structural and optical properties of CZTS thin films deposited by ultrasonically assisted chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Zubair Ansari, Mohd; Khare, Neeraj

    2014-05-01

    Ultrasonically assisted chemical vapour deposition has been used for the deposition of thin films of Cu2ZnSnS4 (CZTS) on glass substrates. The effect of substrate temperature on the structural and optical properties of thin films has been investigated. The CZTS films show a tetragonal structure with preferential orientation along the (1 1 2) plane. X-ray diffraction and Raman studies confirm the formation of a single-phase CZTS film at a deposition temperature of 325 °C. These films show p-type semiconducting behaviour with a carrier concentration ˜1017 cm-3, optical absorption coefficient ˜104 cm-1 and direct optical band gap ˜1.4 eV. At higher substrate temperatures (⩾350 °C), secondary phases of Cu2-xS and SnS2 also start growing along with the CZTS phase. The band gap of CZTS films increases from 1.40 to 1.50 eV as the deposition temperature increases from 325 to 400 °C. The observed higher band gap for CZTS films deposited at 400 °C has been attributed to the growth of the Cu2-xS and SnS2 secondary phase and a sulfur-poor CZTS phase. The activation energy of the CZTS thin film deposited at 325 °C is 15 meV.

  13. Morphological and optical investigation of Sol-Gel ZnO films

    NASA Astrophysics Data System (ADS)

    Ivanova, T.; Harizanova, A.; Petrova, A.

    2016-03-01

    This paper presents morphological and optical studies of the properties of spin-coated ZnO films depending on the annealing temperatures. The films microstructure was explored using a scanning nano-hardness measuring device of the NanoScan family, based on the principles of atomic force microscopy, in a constant frequency mode. The surface study revealed that the root-mean-square (RMS) surface roughness of 985.64×985.64 nm ZnO films becomes greater with the increase of the annealing temperature, but the film surface remains uniform and smooth. The results were confirmed by XRD analysis, which demonstrated that the crystallite size grew from 25 to 36 nm with the thermal treatments. The ZnO films possessed high transmittance in the visible spectral range and the optical band gaps in ZnO films varied from 3.25 eV to 3.52 eV. The optical and morphological properties of the ZnO films formed on Si and quartz substrates are very good. The sol-gel approach proposed for deposition of nanostructured ZnO films is promising for applications in optoelectronic devices or solar cells.

  14. Growth and Optical Properties of Cd1-xZnxS Thin Films

    NASA Astrophysics Data System (ADS)

    Zhou, Zhen; Zhao, Kui; Rockett, Angus

    2010-08-01

    Highly transparent cadmium zinc sulfide (Cd1-xZnxS) thin films were deposited by chemical bath deposition (CBD) under various ammonia and thiourea concentrations, which strongly affected the optical properties of Cd1-xZnxS films at different deposition stages: homogeneous reaction, atom-by-atom process and cluster-by-cluster deposition. Ammonia bound metal ions and, according to complex ion dissociation and equilibrium constants, released small concentration of ions. The hydrolysis of thiourea in the alkaline medium, provided by ammonia hydrolysis, released sulfide ion S2- resulting in the formation of Cd1-xZnxS thin films. In the CBD deposition process, it was important to control the ions concentration released by these two agents. Otherwise, there would be immediate precipitation or existed a large amount colloids in the reactive bath preventing the deposition of thin films. The influences of various ammonia and thiourea concentrations on the growth mechanism and the optical properties of thin films were investigated. The transmission spectra (TS) and spectra-ellipsometry (SE) were measured and the data were modeled and fitted, giving the parameters which were further to estimate the quality of thin films. The optical properties and the parameters indicated that the ammonia concentration played an important role for obtaining high quality Cd1-xZnxS films. All parameters showed that it was more essential to control ammonia concentration in CBD deposition of high quality thin films, compared with thiourea.

  15. Optical properties and bandgap evolution of ALD HfSiOx films.

    PubMed

    Yang, Wen; Fronk, Michael; Geng, Yang; Chen, Lin; Sun, Qing-Qing; Gordan, Ovidiu D; Zhou, Peng; Zahn, Dietrich Rt; Zhang, David Wei

    2015-01-01

    Hafnium silicate films with pure HfO2 and SiO2 samples as references were fabricated by atomic layer deposition (ALD) in this work. The optical properties of the films as a function of the film composition were measured by vacuum ultraviolet (VUV) ellipsometer in the energy range of 0.6 to 8.5 eV, and they were investigated systematically based on the Gaussian dispersion model. Experimental results show that optical constants and bandgap of the hafnium silicate films can be tuned by the film composition, and a nonlinear change behavior of bandgap with SiO2 fraction was observed. This phenomenon mainly originates from the intermixture of d-state electrons in HfO2 and Si-O antibonding states in SiO2.

  16. The Effects of ph on Structural and Optical Characterization of Iron Oxide Thin Films

    NASA Astrophysics Data System (ADS)

    Tezel, Fatma Meydaneri; Özdemir, Osman; Kariper, I. Afşin

    In this study, the iron oxide thin films have been produced by chemical bath deposition (CBD) method as a function of pH onto amorphous glass substrates. The surface images of the films were investigated with scanning electron microscope (SEM). The crystal structures, orientation of crystallization, crystallite sizes, and dislocation density i.e. structural properties of the thin films were analyzed with X-ray diffraction (XRD). The optical band gap (Eg), optical transmission (T%), reflectivity (R%), absorption coefficient (α), refraction index (n), extinction coefficient (k) and dielectric constant (ɛ) of the thin films were investigated depending on pH, deposition time, solution temperature, substrate temperature, thickness of the films by UV-VIS spectrometer.

  17. Optical Properties of Semiconductor-Metal Composite Thin Films in the Infrared Region

    NASA Technical Reports Server (NTRS)

    Nagendra, C. L.; Lamb, James L.

    1993-01-01

    Germanium:Silver (Ge:Ag) composite thin films having different concentrations of Ag, ranging from 7% to 40% have been prepared by dc co-sputtering of Ge an Ag and the films' surface morphology and optical properties have been characterized using transmission electron microscopy (TEM) and infrared spectrophotometry. It is seen that while the films containing lower concentrations of Ag have island-like morphology (i.e. Ag particles distributed in a Ge matrix), the higher metallic concentration films tend to have symmetric distribution of Ag and Ge.

  18. Structural and optical properties of zinc oxide film using RF-sputtering technique

    SciTech Connect

    Hashim, A. J.; Jaafar, M. S.; Ghazai, Alaa J.

    2012-11-27

    This paper reports the fabrication of zinc oxide (ZnO) film using RF-sputtering technique. Determination of the structural properties using High Resolution X-ray Diffraction (HRXRD) confirmed that ZnO film deposited on silicon (Si) substrate has a high quality. This result is in line with the Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) which were used to image the morphology of the film, in which a rough surface was demonstrated. Photoluminescence (PL) emission is included to study the optical properties of ZnO film that shows two PL peak in the UV region at 371 nm and in visible region at 530 nm respectively.

  19. New Numerical Simulation of the Optical Behavior of Nanocrystalline Silicon Thin Films

    NASA Astrophysics Data System (ADS)

    Besahraoui, F.; Bouizem, Y.; Chahed, L.; Sib, J. D.

    2009-11-01

    The absorption enhancement observed on the CPM spectra of nanotextured silicon thin films should be attributed to light scattering effects. A detailed numerical simulation based on Monte Carlo method is presented to calculate the absorption spectra of hydrogenated nanocrystalline silicon films according to the CPM setup. The calculated spectra of apparent optical absorption coefficient depend mainly on the characteristic parameters of nano-Si:H thin film, denoted crystalline/amorphous fraction which favors bulk light scattering phenomena and the film thickness which leads to the light scattering at the rough surface.

  20. The influence of the CIGS film thickness on its growth and optical properties

    NASA Astrophysics Data System (ADS)

    Panchal, C. J.; Ray, J. R.; Desai, M. S.; Rehani, Bharati

    2012-06-01

    CuIn1.xGaxSe2: x = 0.3 (CIGS) bulk compound in the form of powder is prepared using melt-quenching method. Thin films, of CIGS powder, were grown on organically cleaned soda lime glass substrate for different thicknesses ranging from 0.4 μm to 1 μm using the flash evaporation method. The substrate temperature is kept constant at 250°C. The analysis of surface morphology, chemical composition and the optical properties of CIGS thin films reveal that the films of thickness (˜ 1 μm) are more conducive as an absorber layer in thin film solar cell.

  1. Study of environmental biodegradation of LDPE films in soil using optical and scanning electron microscopy.

    PubMed

    Mumtaz, Tabassum; Khan, M R; Hassan, Mohd Ali

    2010-07-01

    An outdoor soil burial test was carried out to evaluate the degradation of commercially available LDPE carrier bags in natural soil for up to 2 years. Biodegradability of low density polyethylene films in soil was monitored using both optical and scanning electron microscopy (SEM). After 7-9 months of soil exposure, microbial colonization was evident on the film surface. Exposed LDPE samples exhibit progressive changes towards degradation after 17-22 months. SEM images reveal signs of degradation such as exfoliation and formation of cracks on film leading to disintegration. The possible degradation mode and consequences on the use and disposal of LDPE films is discussed.

  2. Doped, porous iron oxide films and their optical functions and anodic photocurrents for solar water splitting

    SciTech Connect

    Kronawitter, Coleman X.; Mao, Samuel S.; Antoun, Bonnie R.

    2011-02-28

    The fabrication and morphological, optical, and photoelectrochemical characterization of doped iron oxide films is presented. The complex index of refraction and absorption coefficient of polycrystalline films are determined through measurement and modeling of spectral transmission and reflection data using appropriate dispersion relations. Photoelectrochemical characterization for water photo-oxidation reveals that the conversion efficiencies of electrodes are strongly influenced by substrate temperature during their oblique-angle physical vapor deposition. These results are discussed in terms of the films' morphological features and the known optoelectronic limitations of iron oxide films for application in solar water splitting devices.

  3. Optical and electrical characterizations of nanocomposite film of titania adsorbed onto oxidized multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Feng, Wei; Feng, Yiyu; Wu, Zigang; Fujii, Akihiko; Ozaki, Masanori; Yoshino, Katsumi

    2005-07-01

    Composite film containing titania electrostatically linked to oxidized multiwalled carbon nanotubes (TiO2-s-MWNTs) was prepared from a suspension of TiO2 nanoparticles in soluble carbon nanotubes. The structure of the film was analysed principally by Fourier transform infrared spectroscopy, scanning electron micrography and x-ray diffraction. The optical and electrical characterizations of the film were investigated by UV-vis spectrum, photoluminescence and photoconductivity. The enhancement of photocurrent in the TiO2-s-MWNT film is discussed by taking the photoinduced charge transfer between the MWNT and TiO2 into consideration.

  4. Nonlinear optical characterization of ZnS thin film synthesized by chemical spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    G, Sreeja V.; V, Sabitha P.; Anila, E. I.; R, Reshmi; John, Manu Punnan; Radhakrishnan, P.

    2014-10-01

    ZnS thin film was prepared by Chemical Spray Pyrolysis (CSP) method. The sample was characterized by X-ray diffraction method and Z scan technique. XRD pattern showed that ZnS thin film has hexagonal structure with an average size of about 5.6nm. The nonlinear optical properties of ZnS thin film was studied by open aperture Z-Scan technique using Q-switched Nd-Yag Laser at 532nm. The Z-scan plot showed that the investigated ZnS thin film has saturable absorption behavior. The nonlinear absorption coefficient and saturation intensity were also estimated.

  5. Structural and optical characterization of thermally evaporated bismuth and antimony films for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Srimathy, N.; Ruban Kumar, A.

    2016-05-01

    In this present study, the thin film of bismuth and antimony is coated by thermal evaporation system equipped with the inbuilt ultra high vacuum system. XRD analysis confirmed the rhombohedral structure of Bismuth and Antimony on the prepared film. The surface roughness and physical appearance is analyzed by Atomic force microscopy. The results of Raman Spectroscopy show the wave functions and the spectrum of electrons. The preparation technique and conditions strongly influence the crystalline structure and the phase composition of bismuth and antimony thin films. The electrical and optical properties for the prepared film are analyzed. The results show a great interest and promising applications in Photovoltaic devices.

  6. High-resolution photometric optical monitoring for thin-film deposition.

    PubMed

    Rabady, Rabi; Zinoviev, Kirill; Avrutsky, Ivan

    2004-01-01

    Real-time monitoring of thin-film deposition with high resolution is important for precise fabrication of thin-film devices in a technological environment with ever-increasing demands for smaller size and better performance. Using photometry, we were able to achieve a real-time optical monitoring resolution of film thickness that is comparable with a single atomic layer scale (i.e., subnanometer). Filtering noise efficiently and compensating for sources of error by use of an appropriate model produced this high resolution. The procedure proved reliable and can be useful in the thin-film-deposition industry.

  7. Thin film optical nonlinear waveguides made of Corning 7059 glass doped with CdS microcrystallites

    NASA Astrophysics Data System (ADS)

    Chenard, Francois; Jerominek, Hubert; Larochelle, Sophie; Tremblay, Real; Delisle, Claude A.

    1989-03-01

    The technology for the fabrication of semiconductor-doped glass film by co-sputtering of Coming 7059 and a CdS powder or pellet is described. The presence of semiconductor microcrystallites was verified by using Raman spectroscopy. XPS measurements show that CdS content of the films varies from 3 to 20% by weight depending on the kind of target used and the RF power supplied to the sputtering system. Nonlinear coefficient n2 of the films is about 10-10 m2/W. The nonlinearity is probably of thermal origin. All-optical beam deflection experiment based on nonlinear properties of the deposited films is described.

  8. Nonlinear optical characterization of ZnS thin film synthesized by chemical spray pyrolysis method

    SciTech Connect

    G, Sreeja V; Anila, E. I. R, Reshmi John, Manu Punnan; V, Sabitha P; Radhakrishnan, P.

    2014-10-15

    ZnS thin film was prepared by Chemical Spray Pyrolysis (CSP) method. The sample was characterized by X-ray diffraction method and Z scan technique. XRD pattern showed that ZnS thin film has hexagonal structure with an average size of about 5.6nm. The nonlinear optical properties of ZnS thin film was studied by open aperture Z-Scan technique using Q-switched Nd-Yag Laser at 532nm. The Z-scan plot showed that the investigated ZnS thin film has saturable absorption behavior. The nonlinear absorption coefficient and saturation intensity were also estimated.

  9. Nanomechanical and optical properties of highly a-axis oriented AlN films

    NASA Astrophysics Data System (ADS)

    Jose, Feby; Ramaseshan, R.; Tripura Sundari, S.; Dash, S.; Tyagi, A. K.; Kiran, M. S. R. N.; Ramamurty, U.

    2012-12-01

    This paper reports optical and nanomechanical properties of predominantly a-axis oriented AlN thin films. These films were deposited by reactive DC magnetron sputtering technique at an optimal target to substrate distance of 180 mm. X-ray rocking curve (FWHM = 52 arcsec) studies confirmed the preferred orientation. Spectroscopic ellipsometry revealed a refractive index of 1.93 at a wavelength of 546 nm. The hardness and elastic modulus of these films were 17 and 190 GPa, respectively, which are much higher than those reported earlier can be useful for piezoelectric films in bulk acoustic wave resonators.

  10. Multifunctional organic thin films and their electronic/optical properties

    NASA Astrophysics Data System (ADS)

    Shao, Yan

    The concept of multifunctional organic thin films and their electronic/optical properties has been applied to organic functional device design, fabrication, and characterization. The organic devices involve organic light-emitting diodes (OLEDs) and organic photovoltaic devices (OPV) in this dissertation. In the research of graded junction structure of OLEDs, two kinds of naturally-formed graded junction (NFGJ) structures, sharp and shallow graded junctions, can be formed using single thermal evaporation boat loaded with uniformly mixed charge transport and light-emitting materials. OLEDs with NFGJ have been demonstrated in Chapter 3; the performance is comparable to the heterojunction OLEDs, but with better device lifetime. A novel method to prepare highly uniform mixed organic solid solutions through a high temperature and high-pressure fusion process has been demonstrated in Chapter 4. A series of fused organic solid solution (FOSS) compounds with NPD doped with different organic emitting dopants were prepared and DSC technique was utilized to determine the thermal characteristics. For the first time, the schematic phase diagram for this binary system has been obtained. High performance OLEDs of single color and white emission were fabricated and the device properties were characterized. In Chapter 5, an efficient photovoltaic heterojunction of tetracene and fullerene has been investigated and high performance organic solar cells have been demonstrated by thermal deposition and successive heat treatment. The preliminary conclusion for this enhancement is discussed and supported by atomic force microscopy images, absorption spectra and x-ray diffraction analysis. Additionally, an effective organic photovoltaic heterojunction based on the typical triplet material PtOEP was demonstrated. It is believed that introducing appropriate organic materials with long exciton lifetime is a very promising way to improve photovoltaic performance.

  11. Optical image encryption with a polarization-selective diffractive optical element based on interference

    NASA Astrophysics Data System (ADS)

    Zhu, Nan; Wang, Yongtian; Liu, Juan; Xie, Jinghui

    2010-11-01

    Data security techniques based on optical theories and methods have been proposed and widely developed in recent years. Compared with conventional mathematical encryption methods optical security system provides higher processing speed, more information volume, more encryption free-degree as well as its multi-dimension and parallel processing abilities. In this paper we proposed a novel architecture for optical image encryption with polarization-selective diffractive optical element (PDOE) based on interference theory. A target image is firstly encoded into two phase-only distributions and then these phase distributions are encrypted into the etched surface-relief pattern of a single PDOE mask. In the process of optical image decryption, when the working wavelength and the system configuration are correct, the PDOE mask with the encoded information for the target image can generate two desired polarized wavefronts by modulating the incident light beam. These two wavefronts interfere and then generate the decrypted image. The encoding algorithm to generate the phase-only distributions is simple and it does not need iterative process. The optical realization for image decryption also has the advantages of easier installation and collimation since all the optical elements are in a same optical axis. The employment of the PDOE mask in this optical security system will highly increase the information security and still maintain the parameter sensitivity in an acceptable region. Numerical simulation is performed to demonstrate the validity of this new proposed method.

  12. Depth selective diffuse optical computed topography: simulations and phantom experiments

    NASA Astrophysics Data System (ADS)

    Fujii, M.; Kawanaka, A.; Nakayama, K.

    2007-07-01

    Diffuse optical topography has excellent features as a noninvasive method that provides 2D location information of cortical activity. However, it cannot distinguish the activation depth. We propose an image reconstruction algorithm that suppresses undesirable effects of skin circulation. It comprises a filtering algorithm that extracts target signals from observation data contaminated by disturbing signals and a 2D visualizing process. Computer simulations revealed its excellent performance. We developed a depth selective diffuse optical topography system prototype and performed phantom experiments. Our algorithm significantly suppressed the influence of the disturbing body in the shallow plane with minimal degradation of the target signal.

  13. Tuning optical and three photon absorption properties in graphene oxide-polyvinyl alcohol free standing films

    NASA Astrophysics Data System (ADS)

    Karthikeyan, B.; Udayabhaskar, R.; Hariharan, S.

    2016-07-01

    We report the optical and nonlinear optical properties of graphene oxide (GO)-polyvinyl alcohol (PVA) free standing films. The composite polymer films were prepared in ex-situ method. The variation in optical absorption spectra and optical constants with the amount of GO loading was noteworthy from the optical absorption spectroscopic studies. Nonlinear optical studies done at 532 nm using 5 ns laser pulses show three photon absorption like behaviour. Both steady state and time resolved fluorescence studies reveal that the GO was functioning as a pathway for the decay of fluorescence from PVA. This is attributed to the energy level modifications of GO through hydroxyl groups with PVA. Raman spectroscopy also supports the interaction between GO and PVA ions through OH radicals.

  14. Tuning optical and three photon absorption properties in graphene oxide-polyvinyl alcohol free standing films

    SciTech Connect

    Karthikeyan, B. Hariharan, S.; Udayabhaskar, R.

    2016-07-11

    We report the optical and nonlinear optical properties of graphene oxide (GO)-polyvinyl alcohol (PVA) free standing films. The composite polymer films were prepared in ex-situ method. The variation in optical absorption spectra and optical constants with the amount of GO loading was noteworthy from the optical absorption spectroscopic studies. Nonlinear optical studies done at 532 nm using 5 ns laser pulses show three photon absorption like behaviour. Both steady state and time resolved fluorescence studies reveal that the GO was functioning as a pathway for the decay of fluorescence from PVA. This is attributed to the energy level modifications of GO through hydroxyl groups with PVA. Raman spectroscopy also supports the interaction between GO and PVA ions through OH radicals.

  15. Micromachined interferometric and atomic sensors enabled by integrated thin film optics

    NASA Astrophysics Data System (ADS)

    Perez, Maximillian A.

    In this thesis, thin film optical techniques as applied to micromachined devices with optical detection are explored for the formation of high precision sensors. Specifically, two micromachined optical MEMS devices are introduced, fabricated, and characterized. The first is an accelerometer based on parallel plate Fabry-Perot interferometers. The second is a vapor cell for use in chip scale atomic MEMS sensor applications. Both devices are fabricated using bulk micromachining with integrated thin film reflectors. A single axis Fabry-Perot accelerometer with integrated thin film reflectors is designed, fabricated and demonstrated to have a resolution better than 1 mu g/ Hz at a frequency of 2 kHz. The effect of squeeze film constriction in such devices is characterized in similar devices and shown to be capable of extending the sensor bandwidth by as much as 48% over ideally vented designs. Two thin film reflector techniques are demonstrated to form wavelength dependant reflectors that allow the serialization of Fabry-Perot accelerometers into linear serial arrays based on the wavelength division multiplexing of the optical signals. A linear array of two optically multiplexed devices is demonstrated. Similar multilayer reflectors are integrated onto the angled interior sidewalls of an atomic MEMS vapor cell to improve the optical return performance by as much as seven times. The techniques is demonstrated to be compatible with the encapsulation of the 87Rb isotope. Advanced reflector designs are introduced to overcome the challenges of integrating multilayer reflectors into the micromachined cavities forming the vapor cells.

  16. Large electro-optic coefficient in single-crystal film of a novel organic salt, DASMS

    NASA Astrophysics Data System (ADS)

    Tan, Shida; Ahyi, Ayayi; Mishra, Alpana; Thakur, Mrinal

    2001-03-01

    We have synthesized a novel electro-optic material 4'-dimethylamino-4-methylstilbazolium methanesulfonate (DASMS). Large-area ( 60 mm^2), single-crystal films of DASMS with excellent optical quality have been grown for the first time by a modified shear method^1. These films have the noncentrosymmetric hydrated phase, which is electro-optically active^2. Polarized optical microscopy, X-ray diffraction and polarized UV-visible spectroscopic studies have been used to characterize the films. The single-crystal films were observed to be highly dichroic. Using field-induced birefringence measurement, the electro-optic coefficient of DASMS at 632.8 nm has been estimated to be r_11 160 pm/V, which is five times larger than the eletro-optic coefficient of LiNbO_3. For a 1.8 μm thick film, 28% intensity modulation was observed for an electric field of 4 V/μm. 1. M. Thakur and S. Meyler, Macromolecules 18, 2341 (1985); M. Thakur, Y. Shani, G. C. Chi, and K. O'Brien, Synth. Met. 28, D595 (1989). 2. E. P. Boden, P. D. Phelps, C. P. Yakymyshyn, and K. R. Stewart, US patent 5,194,584.

  17. Monte Carlo Simulation of the Optical Absorption of Hydrogenated Nanocrystalline Silicon Thin Films

    NASA Astrophysics Data System (ADS)

    Besahraoui, Fatiha; Sib, Jamal Dine; Bouizem, Yahia; Chahed, Larbi

    2008-05-01

    The optical absorption coefficient measured by Constant Photocurrent Method (CPM) for nanotextured silicon thin films is apparent affected by light scattering produced in these heterogeneous materials. A detailed Monte Carlo simulation of the absorption spectra and the random optical paths traveled by the scattered photons is presented for the case of nano-Si:H layers. The calculated values of apparent absorption coefficient and the mean optical path depend mainly on the variation of the included nanocrystallites fraction, which favors bulk light scattering phenomena. The particular structure of these materials is a key characteristic of efficient thin films solar cells.

  18. Calculation of optical and electronic properties of modeled titanium dioxide films of different densities.

    PubMed

    Turowski, Marcus; Amotchkina, Tatiana; Ehlers, Henrik; Jupé, Marco; Ristau, Detlev

    2014-02-01

    The electronic and optical properties of TiO2 atomic structures representing simulated thin films have been investigated using density functional theory. Suitable model parameters and system sizes have been identified in advance by validation of the results with experimental data. Dependencies of the electronic band gap and the refractive index have been calculated as a function of film density. The results of the performed calculations have been compared to characterized optical properties of titania single layers deposited using different coating techniques. The modeled dependencies are consistent with experimental observations, and absolute magnitudes of simulated values are in agreement with measured optical data.

  19. Preparation, characterization, and nonlinear optical properties of graphene oxide-carboxymethyl cellulose composite films

    NASA Astrophysics Data System (ADS)

    Wang, Jiaojiao; Feng, Miao; Zhan, Hongbing

    2014-04-01

    The preparation and characterization of free-standing films made of a graphene oxide-carboxymethyl cellulose composite material is described. Characterization was accomplished using transmission electron microscopy, ultraviolet-visible absorption spectroscopy, Raman spectroscopy, and thermal gravimetric analysis. The nonlinear optical performance of this composite material was studied using the open aperture Z-scan technique in the nanosecond regime using a 532-nm wavelength laser. Results show that the composite has nonlinear optical properties that are much enhanced when composited with graphene oxide. All phenomena indicate that the film is a potential candidate for optical limiting applications.

  20. Removal of hydrocarbon contaminant film from spacecraft optical surfaces using a radiofrequency-excited oxygen plasma.

    NASA Technical Reports Server (NTRS)

    Beverly, W. D.; Gillete, R. B.; Cruz, G. A.

    1973-01-01

    Results of a study on the feasibility of removing contaminant films from optical surfaces in vacuum, using an oxygen plasma, are discussed. Contaminant films were deposited onto optical surfaces from butadiene and methane gases at a pressure of about 4 torr in the presence of ultraviolet radiation. Optical surfaces evaluated included ultraviolet-reflecting mirrors, gratings, quartz disks, and spacecraft thermal control surfaces. In general, it was found that contaminants could be removed successfully from surfaces using an oxygen plasma. Exceptions were the white-paint thermal control surfaces, which, when contaminated, degraded further during exposure to the oxygen plasma.