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Sample records for optical coatings grown

  1. Morphology and Optical Properties of Zinc Oxide Films Grown on Metal Coated Glass Substrates by Aqueous Chemical Growth

    NASA Astrophysics Data System (ADS)

    Bakar, M. A.; Hamid, M. A. A.; Jalar, A.; Shamsudin, R.

    2013-04-01

    Zinc oxide films were deposited on three different metal coated substrates (gold, nickel and platinum) by aqueous chemical growth method. This paper discusses the effect of metal coated substrates on the morphology and optical properties of grown ZnO films. X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and UV-visible spectroscopy (UV-vis) were employed to characterize the samples. All the as-deposited ZnO films exhibit crystalline hexagonal wurzite structure. The crystallite size of the ZnO films were in the range of 29 to 32 nm. FESEM micrographs revealed hexagonal rod, oval-like and flower-like ZnO structures formed on all metal coated substrates. The Pt coated film contains higher density hexagonal rod as compared to others metal coated substrate. Most probably the Pt lattice parameter is the nearest to ZnO compared to nickel and gold. The optical band gap energy, Eg of ZnO films were estimated to be 3.30 eV which is near to bulk Eg, 3.37 eV. This indicates that the ZnO grown by aqueous chemical growth is able to produce similar quality properties to other conventional method either films or bulk size.

  2. Large-Area Optical Coatings with Uniform Thickness Grown by Surface Chemical Reactions for High-Power Laser Applications

    NASA Astrophysics Data System (ADS)

    Zaitsu, Shin-ichi; Motokoshi, Shinji; Jitsuno, Takahisa; Nakatsuka, Masahiro; Yamanaka, Tatsuhiko

    2002-01-01

    We prepared optical thin films using an atomic layer deposition (ALD) procedure in order to apply this coating method to optical components for high-power and large-scale lasers. Film thickness shows a proportional relationship to the number of operation cycles even in the case of room-temperature growth, and the distribution is uniform with a thickness error of less than 1% over an area of 240 mm diameter. We examined the laser damage thresholds of the films with 1 ns laser pulses at 1.064 μm. The highest thresholds (TiO2: 5 J/cm2, Al2O3: 5.2 J/cm2) are obtained in the amorphous films grown at low growth temperatures (25-50°C). Results from the analysis of film structure and composition, and measurement of optical absorption reveal that the decrease in laser damage threshold as the growth temperature rises is caused by the crystallization of films.

  3. Studies on the effect of polymer coating on solution grown hygroscopic non-linear optical single crystal of L-lysine monohydrochloride.

    PubMed

    Rani, Neelam; Vijayan, N; Maurya, K K; Haranath, D; Saini, Parveen; Rathi, Brijesh; Wahab, M A; Bhagavanarayana, G

    2012-11-01

    Nonlinear optical single crystals are getting attention because of its enormous applications in the area of fiber optic communication and optical signal processing. In this article, we are reporting the single crystal growth of l-lysine monohydrochloride by slow evaporation solution growth technique, by using double distilled water as the solvent. We found that the grown single crystal is bulk in size and fairly transparent. But after a period of time, due to its hygroscopic nature, the transparency is completely vanished and became opaque. Then we have attempted to coat the poly methyl methacrylate (PMMA) polymer on the surface of l-lysine monohydrochloride (l-LMHCL) single crystal by dip coating method. This polymer coating is giving resistance to hygroscopic nature and also acting as thin protective covering layer without affecting the other properties. Then we have systematically studied the different properties of bare, polymer coated and hygroscopic l-LMCHL single crystals. Its crystalline perfection was examined by high resolution X-ray diffractometer and found major differences in crystalline quality. Its structural and optical behavior was assessed by powder X-ray diffraction, UV-vis and luminescence analyses.

  4. Optical coating in space

    NASA Technical Reports Server (NTRS)

    Bunner, A. N.

    1983-01-01

    A technological appraisal of the steps required to approach the goal of in-situ optical coating, cleaning and re-coating the optical elements of a remote telescope in space is reported. Emphasis is placed on the high ultraviolet throughput that a telescope using bare aluminum mirrors would offer. A preliminary design is suggested for an Orbital Coating Laboratory to answer basic technical questions.

  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. Multilayer optical dielectric coating

    DOEpatents

    Emmett, John L.

    1990-01-01

    A highly damage resistant, multilayer, optical reflective coating includes alternating layers of doped and undoped dielectric material. The doping levels are low enough that there are no distinct interfaces between the doped and undoped layers so that the coating has properties nearly identical to the undoped material. The coating is fabricated at high temperature with plasma-assisted chemical vapor deposition techniques to eliminate defects, reduce energy-absorption sites, and maintain proper chemical stoichiometry. A number of differently-doped layer pairs, each layer having a thickness equal to one-quarter of a predetermined wavelength in the material are combined to form a narrowband reflective coating for a predetermined wavelength. Broadband reflectors are made by using a number of narrowband reflectors, each covering a portion of the broadband.

  7. Effects of Precursor Concentration on Structural and Optical Properties of ZnO Thin Films Grown on Muscovite Mica Substrates by Sol-Gel Spin-Coating.

    PubMed

    Kim, Younggyu; Leem, Jae-Young

    2016-05-01

    The structural and optical properties of the ZnO thin films grown on mica substrates for different precursor concentrations were investigated. The surface morphologies of all the samples indicated that they consisted of granular structures with spherical nano-sized crystallites. The thickness of the ZnO thin films increased significantly and the optical band gap exhibited a blue shift with an increase in the precursor concentration. It is remarkable that the highest I(NBE)/I(DLE) ratio was observed for the ZnO thin film with 0.8 M precursor concentration, even though cracks formed on the surface of this film.

  8. Metasurface optical antireflection coating

    SciTech Connect

    Zhang, Boyang; Hendrickson, Joshua; Nader, Nima; Chen, Hou -Tong; Guo, Junpeng

    2014-12-15

    Light reflection at the boundary of two different media is one of the fundamental phenomena in optics, and reduction of reflection is highly desirable in many optical systems. Traditionally, optical antireflection has been accomplished using single- or multiple-layer dielectric films and graded index surface structures in various wavelength ranges. However, these approaches either impose strict requirements on the refractive index matching and film thickness, or involve complicated fabrication processes and non-planar surfaces that are challenging for device integration. Here, we demonstrate an antireflection coating strategy, both experimentally and numerically, by using metasurfaces with designer optical properties in the mid-wave infrared. Our results show that the metasurface antireflection is capable of eliminating reflection and enhancing transmission over a broad spectral band and a wide incidence angle range. The demonstrated antireflection technique has no requirement on the choice of materials and is scalable to other wavelengths.

  9. Metasurface optical antireflection coating

    DOE PAGES

    Zhang, Boyang; Hendrickson, Joshua; Nader, Nima; ...

    2014-12-15

    Light reflection at the boundary of two different media is one of the fundamental phenomena in optics, and reduction of reflection is highly desirable in many optical systems. Traditionally, optical antireflection has been accomplished using single- or multiple-layer dielectric films and graded index surface structures in various wavelength ranges. However, these approaches either impose strict requirements on the refractive index matching and film thickness, or involve complicated fabrication processes and non-planar surfaces that are challenging for device integration. Here, we demonstrate an antireflection coating strategy, both experimentally and numerically, by using metasurfaces with designer optical properties in the mid-wave infrared.more » Our results show that the metasurface antireflection is capable of eliminating reflection and enhancing transmission over a broad spectral band and a wide incidence angle range. The demonstrated antireflection technique has no requirement on the choice of materials and is scalable to other wavelengths.« less

  10. The effect of ALD-grown Al2O3 on the refractive index sensitivity of CVD gold-coated optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Mandia, David J.; Zhou, Wenjun; Ward, Matthew J.; Joress, Howie; Sims, Jeffrey J.; Giorgi, Javier B.; Albert, Jacques; Barry, Seán T.

    2015-10-01

    The combined effect of nanoscale dielectric and metallic layers prepared by atomic layer deposition (ALD) and chemical vapor deposition (CVD) on the refractometric properties of tilted optical fiber Bragg gratings (TFBG) is studied. A high index intermediate layer made up of either 50 nm or 100 nm layers of Al2O3 (refractive index near 1.62) was deposited by ALD and followed by thin gold layers (30-65 nm) deposited from a known single-source gold (I) iminopyrrolidinate CVD precursor. The fabricated devices were immersed in different surrounding refractive indices (SRI) and the spectral transmission response of the TFBGs was measured. Preliminary results indicate that the addition of the dielectric Al2O3 pre-coating enhances the SRI sensitivity by up to 75% but this enhancement is highly dependent on the polarization and dielectric thickness. In fact, the sensitivity decreases by up to 50% for certain cases. These effects are discussed with support from TFBG simulations and models, by quantifying the penetration of the evanescently coupled light out of the fiber through the various coating layers. Additional characterization studies have been carried out on these samples to further correlate the optical behaviour of the coated TFBGs with the physical properties of the gold and Al2O3 layers, using atomic force microscopy x-ray photoelectron spectroscopy and an ensemble of other optical and x-ray absorption spectroscopy techniques. The purity, roughness, and morphology of gold thin films deposited by CVD onto the dielectric-TFBG surface are also provided.

  11. The effect of ALD-grown Al₂O₃ on the refractive index sensitivity of CVD gold-coated optical fiber sensors.

    PubMed

    Mandia, David J; Zhou, Wenjun; Ward, Matthew J; Joress, Howie; Sims, Jeffrey J; Giorgi, Javier B; Albert, Jacques; Barry, Seán T

    2015-10-30

    The combined effect of nanoscale dielectric and metallic layers prepared by atomic layer deposition (ALD) and chemical vapor deposition (CVD) on the refractometric properties of tilted optical fiber Bragg gratings (TFBG) is studied. A high index intermediate layer made up of either 50 nm or 100 nm layers of Al2O3 (refractive index near 1.62) was deposited by ALD and followed by thin gold layers (30-65 nm) deposited from a known single-source gold (I) iminopyrrolidinate CVD precursor. The fabricated devices were immersed in different surrounding refractive indices (SRI) and the spectral transmission response of the TFBGs was measured. Preliminary results indicate that the addition of the dielectric Al2O3 pre-coating enhances the SRI sensitivity by up to 75% but this enhancement is highly dependent on the polarization and dielectric thickness. In fact, the sensitivity decreases by up to 50% for certain cases. These effects are discussed with support from TFBG simulations and models, by quantifying the penetration of the evanescently coupled light out of the fiber through the various coating layers. Additional characterization studies have been carried out on these samples to further correlate the optical behaviour of the coated TFBGs with the physical properties of the gold and Al2O3 layers, using atomic force microscopy x-ray photoelectron spectroscopy and an ensemble of other optical and x-ray absorption spectroscopy techniques. The purity, roughness, and morphology of gold thin films deposited by CVD onto the dielectric-TFBG surface are also provided.

  12. Colorimetry in optical coating

    NASA Astrophysics Data System (ADS)

    Oleari, Claudio

    2005-09-01

    Generally, the colour of the non-luminous objects in nature is due to absorption, diffusion and refraction of light. The colour of the optical coatings, as that of some kind of bird feathers, soap bubbles, butterfly wings, some insects, etc. is due to interference and therefore is named interference colour. This kind of colour belongs to the gonio-apparent or special-effect colours. Generally, industrial colorimetry does not deal with interference colour and the usual colorimetric instruments are inadequate to measure it. Only recently, with the new mica-pigment coatings, colorimetry is considering the measurement of the interference colour and new multiangle spectrophotometers are produced. This work is a general introduction to the ground of colorimetry and, at the end, deals with interference colours. A short overview is given of the Physiological Optics and of the Colorimetric Standards of the "Commission International de l'Eclairage" (CIE): particularly, Psychophysical Colorimetry, Psychometrical Colorimetry and Measurement Geometries are summarised. The colorimetry of gonio-apparent colours is considered. For a complete and detailed optical characterisation of interference colour the measurement of bidirectional transmittance and reflectance is needed. Particularly, basic elements for the colorimetric analysis of the interface between isotropic non-absorbing media and for thin monolayers are given.

  13. Nonoptical characterization of optical coatings.

    PubMed

    Guenther, K H

    1981-10-15

    Besides the theoretical design of optical interference coatings, the knowledge of their nonoptical properties like chemical composition, structural features, mechanical peculiarities, and environmental stability is often a basic condition for their industrial production. After some remarks on specifications and standards relevant for optical coatings this paper gives a review on various possibilities for nonoptical characterization of optical coatings. Those methods of surface analysis, depth profiling, and electron microscopy available to and widely used by a major coating manufacturer-like Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS), scanning electron microscopy (SEM), energy dispersive (ED) and wavelength dispersive (WD) electron probe microanalysis (EPMA)-are pointed out in more detail and illustrated with examples from daily practice. Other characterization methods, which are less common but very interesting, are also briefly reviewed.

  14. Pedestal substrate for coated optics

    DOEpatents

    Hale, Layton C.; Malsbury, Terry N.; Patterson, Steven R.

    2001-01-01

    A pedestal optical substrate that simultaneously provides high substrate dynamic stiffness, provides low surface figure sensitivity to mechanical mounting hardware inputs, and constrains surface figure changes caused by optical coatings to be primarily spherical in nature. The pedestal optical substrate includes a disk-like optic or substrate section having a top surface that is coated, a disk-like base section that provides location at which the substrate can be mounted, and a connecting cylindrical section between the base and optics or substrate sections. The connecting cylindrical section may be attached via three spaced legs or members. However, the pedestal optical substrate can be manufactured from a solid piece of material to form a monolith, thus avoiding joints between the sections, or the disk-like base can be formed separately and connected to the connecting section. By way of example, the pedestal optical substrate may be utilized in the fabrication of optics for an extreme ultraviolet (EUV) lithography imaging system, or in any optical system requiring coated optics and substrates with reduced sensitivity to mechanical mounts.

  15. Nanocomposite multilayer optically variable coatings

    NASA Astrophysics Data System (ADS)

    Lu, Junxia; Lai, Zhenquan; Wei, Jiandong; Zhang, Huilin; Deng, Zhongsheng; Zhang, Qinyuan; Wang, Jue

    2000-11-01

    The optically variable coatings can prevent counterfeiting of value documents. The cost of these coatings deposited by physical technology is very high. The sol-gel technology has the feature of a relatively lower cost and can be used to produce thin films with low refractive. We studied the optically variable coatings by the nano-composite technology (i.e., compound method of sol-gel technology and physical technology). The degree of color shift of some film structures with the viewing angle, including PET (substrate)/Cr/SiO2/Al and PET(sub.)/Cr/resin/Al etc., was calculated according to the color perception of human eyes. And the coatings produced were measured with the spectrometer.

  16. Vacuum deposited optical coatings experiment

    NASA Technical Reports Server (NTRS)

    Charlier, Jean

    1992-01-01

    The 138-4 Frecopa experiment consisted of 20 sorts of optical components and coatings subjected to space exposure. They covered a large range of use from the UV to IR spectrum: filters, mirrors, dichroics, beam splitters, and antireflection coatings made of several different materials as layers and substrates. By comparing pre- and post-flight spectral performances, it was possible to put into evidence the alterations due to space exposure.

  17. Mixed oxide coatings for optics.

    PubMed

    Stenzel, Olaf; Wilbrandt, Steffen; Schürmann, Mark; Kaiser, Norbert; Ehlers, Henrik; Mende, Mathias; Ristau, Detlev; Bruns, Stefan; Vergöhl, Michael; Stolze, Markus; Held, Mario; Niederwald, Hansjörg; Koch, Thomas; Riggers, Werner; Burdack, Peer; Mark, Günter; Schäfer, Rolf; Mewes, Stefan; Bischoff, Martin; Arntzen, Markus; Eisenkrämer, Frank; Lappschies, Marc; Jakobs, Stefan; Koch, Stephan; Baumgarten, Beate; Tünnermann, Andreas

    2011-03-20

    Material mixtures offer new possibilities for synthesizing coating materials with tailored optical and mechanical properties. We present experimental results on mixtures of HfO2, ZrO2, and Al2O3, pursuing applications in UV coating technology, while the mixtures are prepared by magnetron sputtering, ion beam sputtering, plasma ion-assisted deposition (PIAD), and electron beam evaporation without assistance. The properties investigated include the refractive index, optical gap, thermal shift, and mechanical stress. The first high reflectors for UV applications have been deposited by PIAD.

  18. Optically enhanced SnO2/CdSe core/shell nanostructures grown by sol-gel spin coating method

    NASA Astrophysics Data System (ADS)

    Kumar, Vijay; Rajaram, P.; Goswami, Y. C.

    2015-08-01

    Synthesis of SnO2/CdSe metal oxide/ chalcogenide nanostructures on glass micro slides using ultrasonic sol-gel process followed by spin coating has been reported. Stannous chloride, cadmium chloride and selenium dioxide compounds were used for Sn, Cd and Se precursors respectively. Ethylene glycol was used as complexing agent. The samples were characterized by XRD, SEM, AFM and UV-spectrophotometer. All the peaks shown in diffractograms are identified for SnO2. Peak broadening observed in core shell due to stress behavior of CdSe lattice. Scanning electron microscope and AFM exhibits the conversion of cluster in to nanorods structures forms. Atomic force microscope shows the structures in nanorods form and a roughness reduced 1.5194 nm by the deposition of CdSe. Uv Visible spectra shows a new absorption edge in the visible region make them useful for optoelectronic applications.

  19. Optically enhanced SnO{sub 2}/CdSe core/shell nanostructures grown by sol-gel spin coating method

    SciTech Connect

    Kumar, Vijay Goswami, Y. C.; Rajaram, P.

    2015-08-28

    Synthesis of SnO{sub 2}/CdSe metal oxide/ chalcogenide nanostructures on glass micro slides using ultrasonic sol-gel process followed by spin coating has been reported. Stannous chloride, cadmium chloride and selenium dioxide compounds were used for Sn, Cd and Se precursors respectively. Ethylene glycol was used as complexing agent. The samples were characterized by XRD, SEM, AFM and UV-spectrophotometer. All the peaks shown in diffractograms are identified for SnO{sub 2}. Peak broadening observed in core shell due to stress behavior of CdSe lattice. Scanning electron microscope and AFM exhibits the conversion of cluster in to nanorods structures forms. Atomic force microscope shows the structures in nanorods form and a roughness reduced 1.5194 nm by the deposition of CdSe. Uv Visible spectra shows a new absorption edge in the visible region make them useful for optoelectronic applications.

  20. Polarization Aberrations of Optical Coatings

    NASA Astrophysics Data System (ADS)

    Jota, Thiago

    This work does not limit itself to its title and touches on a number of related topics beyond it. Starting with the title, Polarization Aberrations of Optical Coatings, the immediate question that comes to mind is: what coatings? All coatings? Not all coatings, but just enough that a third person could take this information and apply it anywhere: to all coatings. The computational work-flow required to break-down the aberrations caused by polarizing events (3D vector forms of reflection and refraction) in dielectric and absorbing materials and for thick and thin films is presented. Therefore, it is completely general and of interest to the wide optics community. The example system is a Ritchey-Chretien telescope. It looks very similar to a Cassegrain, but it is not. It has hyperbolic surfaces, which allows for more optical aberration corrections. A few modern systems that use this configuration are the Hubble Space Telescope and the Keck telescopes. This particular system is a follow-up on this publication, where an example Cassegrain with aluminum coatings is characterized, and I was asked to simply evaluate it at another wavelength. To my surprise, I found a number of issues which lead me to write a completely new, one-of-its-kind 3D polarization ray-tracing code. It can do purely geometrical ray-tracing with add-on the polarization analysis capability, and more importantly: it keeps your data at your fingertips while offering all the outstanding facilities of Mathematica. The ray-tracing code and its extensive library, which can do several advanced computations, is documented in the appendix. The coatings of the Ritchey-Chretien induce a number of aberrations, primarily, but not limited to: tilt, defocus, astigmatism, and coma. I found those forms to exist in both aluminum and with a reflectance-enhancing dielectric quarter-wave multilayer coating over aluminum. The thickness of the film stack varies as function of position to present a quarter-wave of optical

  1. Feature issue on optical interference coatings.

    PubMed

    Macleod, H A; Carniglia, C K

    1993-10-01

    The feature issue on Optical Interference Coatings, stimulated by the June 1992 Topical Meeting, covers the wider field of optical surface treatments after polishing. It is the latest in a series that has been running every four years since 1976.

  2. Optical interference coatings for optics and photonics [Invited].

    PubMed

    Lee, Cheng-Chung

    2013-01-01

    Optical interference coatings play as an important role in the progress in optics and photonics. In this article we give a minireview of the evolution of optical interference coatings from the theory, the design, to the manufacture. Some interesting but challenging topics for the future are also discussed.

  3. Interferometric nanoporous anodic alumina photonic coatings for optical sensing.

    PubMed

    Chen, Yuting; Santos, Abel; Wang, Ye; Kumeria, Tushar; Wang, Changhai; Li, Junsheng; Losic, Dusan

    2015-05-07

    Herein, we present a systematic study on the development, optical optimization and sensing applicability of colored photonic coatings based on nanoporous anodic alumina films grown on aluminum substrates. These optical nanostructures, so-called distributed Bragg reflectors (NAA-DBRs), are fabricated by galvanostatic pulse anodization process, in which the current density is altered in a periodic manner in order to engineer the effective medium of the resulting photonic coatings. As-prepared NAA-DBR photonic coatings present brilliant interference colors on the surface of aluminum, which can be tuned at will within the UV-visible spectrum by means of the anodization profile. A broad library of NAA-DBR colors is produced by means of different anodization profiles. Then, the effective medium of these NAA-DBR photonic coatings is systematically assessed in terms of optical sensitivity, low limit of detection and linearity by reflectometric interference spectroscopy (RIfS) in order to optimize their nanoporous structure toward optical sensors with enhanced sensing performance. Finally, we demonstrate the applicability of these photonic nanostructures as optical platforms by selectively detecting gold(iii) ions in aqueous solutions. The obtained results reveal that optimized NAA-DBR photonic coatings can achieve an outstanding sensing performance for gold(iii) ions, with a sensitivity of 22.16 nm μM(-1), a low limit of detection of 0.156 μM (i.e. 30.7 ppb) and excellent linearity within the working range (0.9983).

  4. Protective, Sacrificial Coats On Optical Surfaces

    NASA Technical Reports Server (NTRS)

    Babel, Henry W.; Hasegawa, Mark M.; Jones, Cherie A.

    1994-01-01

    Clear, easily cleaned sacrificial coats of polytetrafluoroethylene, polyurethane, silicone, or other low-outgassing organic films help maintain optical properties of surfaces of radiators, solar panels, and other components. Contamination removed by erosion of coats. Applied by conventional spraying or other techniques. Originally coats intended to protect surfaces of radiators on spacecraft in low orbit around the Earth. On Earth, used to protect optical surfaces against damage during manufacture or protect and facilitate cleaning of optical surfaces particularly delicate or otherwise not cleaned easily.

  5. Protective, Sacrificial Coats On Optical Surfaces

    NASA Technical Reports Server (NTRS)

    Babel, Henry W.; Hasegawa, Mark M.; Jones, Cherie A.

    1994-01-01

    Clear, easily cleaned sacrificial coats of polytetrafluoroethylene, polyurethane, silicone, or other low-outgassing organic films help maintain optical properties of surfaces of radiators, solar panels, and other components. Contamination removed by erosion of coats. Applied by conventional spraying or other techniques. Originally coats intended to protect surfaces of radiators on spacecraft in low orbit around the Earth. On Earth, used to protect optical surfaces against damage during manufacture or protect and facilitate cleaning of optical surfaces particularly delicate or otherwise not cleaned easily.

  6. Optical coatings for metamaterials (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Jen, Yi-Jun

    2016-09-01

    Optical coatings have been referred as thin films that create interference effect to change optical properties of substrates. The most common applications of optical thin films are anti-reflection coatings, high reflective coatings, beamsplitter coatings, and bandpass filter coatings. In the recent development of metamaterials, the optical coatings also play a critical role in design, fabrication and measurement. In fabrication, glancing angle deposition has been applied to grow slanted metal nanorod arrays. The associated longitudinal plasmon and transverse plasmon modes under linear polarized illuminations are induced and generate anisotropic refractive index and extinction coefficient. Strong birefringence of a silver nanorod array reveals positive and negative real refractive indices exist for two orthogonal linear polarization states. Recently, negative index materials and hyperbolic metamaterials are realized as multilayers comprising subwavelength-scale metal and dielectric films alternatively. From the view of optical coatings, the design of optical edge filters can be applied to arrange the metal-dielectric multilayer as a symmetrical film sack to perform equivalent complex admittance and refractive index. On the other hand, the traditional admittance diagram used in design of antireflection and bandpass filters can be applied to induce the transmission of a negative index multilayer. The admittance loci of metal films are designed to be huge contours in the admittance diagram to reduce the energy loss in metal films. Five-layered symmetrical film stack and seven-layered symmetrical film stack are shown here to present as new bandpass filters with negative real refractive indices.

  7. Surface figure control for coated optics

    DOEpatents

    Ray-Chaudhuri, Avijit K.; Spence, Paul A.; Kanouff, Michael P.

    2001-01-01

    A pedestal optical substrate that simultaneously provides high substrate dynamic stiffness, provides low surface figure sensitivity to mechanical mounting hardware inputs, and constrains surface figure changes caused by optical coatings to be primarily spherical in nature. The pedestal optical substrate includes a disk-like optic or substrate section having a top surface that is coated, a disk-like base section that provides location at which the substrate can be mounted, and a connecting cylindrical section between the base and optics or substrate sections. The optic section has an optical section thickness.sup.2 /optical section diameter ratio of between about 5 to 10 mm, and a thickness variation between front and back surfaces of less than about 10%. The connecting cylindrical section may be attached via three spaced legs or members. However, the pedestal optical substrate can be manufactured from a solid piece of material to form a monolith, thus avoiding joints between the sections, or the disk-like base can be formed separately and connected to the connecting section. By way of example, the pedestal optical substrate may be utilized in the fabrication of optics for an extreme ultraviolet (EUV) lithography imaging system, or in any optical system requiring coated optics and substrates with reduced sensitivity to mechanical mounts.

  8. Polyimide-coated embedded optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Nath, Dilip K.; Nelson, Gary W.; Griffin, Stephen E.; Harrington, C. T.; He, Yi-Fei; Reinhart, Lawrence J.; Paine, D. C.; Morse, Theodore F.

    1991-10-01

    The present paper describes the behavior of embedded optical sensor fibers in a high- temperature PEEK (polyether ether ketone) carbon fiber composite. Sheets of this material, 200 micrometers thick, were layered in alternating directions for the carbon fibers. Typically, 16 sheets were used to form 3' X 6' or 3' X 8' panels by placing the optical fibers in the middle of the `prepreg' sheets, which were then heated to the processing temperature, and subjected to a pressure of 300 psi during the cool-down phase. Since the ordinary polymeric coatings of optical fibers cannot survive the 380 degree(s)C to 400 degree(s)C processing temperature of PEEK impregnated fiber composites, all of the optical sensor fibers tested were polyimide coated. The optical, mechanical, and thermal properties are reported and it is concluded that polyimide coated fibers can withstand PEEK processing conditions.

  9. Optical interference coatings design contest 2004.

    PubMed

    Tilsch, Markus; Hendrix, Karen; Verly, Pierre

    2006-03-01

    A manufacturable, broadband, broad-angle antireflection (AR) coating for the visible (13 designs submitted) and a minimum-shift immersed short-pass filter (12 designs submitted) were the subjects of the design contest held in conjunction with the 2004 Optical Interference Coatings topical meeting of the Optical Society of America. Under the specified constraints, the broadband, broad-angle AR coating could be made more than 65 nm wide. The statistical stability of manufacturing simulations is discussed. The short-pass filter could operate up to a +/- 5.5 degree angular range. The submitted designs are described and evaluated.

  10. Interferometric nanoporous anodic alumina photonic coatings for optical sensing

    NASA Astrophysics Data System (ADS)

    Chen, Yuting; Santos, Abel; Wang, Ye; Kumeria, Tushar; Wang, Changhai; Li, Junsheng; Losic, Dusan

    2015-04-01

    Herein, we present a systematic study on the development, optical optimization and sensing applicability of colored photonic coatings based on nanoporous anodic alumina films grown on aluminum substrates. These optical nanostructures, so-called distributed Bragg reflectors (NAA-DBRs), are fabricated by galvanostatic pulse anodization process, in which the current density is altered in a periodic manner in order to engineer the effective medium of the resulting photonic coatings. As-prepared NAA-DBR photonic coatings present brilliant interference colors on the surface of aluminum, which can be tuned at will within the UV-visible spectrum by means of the anodization profile. A broad library of NAA-DBR colors is produced by means of different anodization profiles. Then, the effective medium of these NAA-DBR photonic coatings is systematically assessed in terms of optical sensitivity, low limit of detection and linearity by reflectometric interference spectroscopy (RIfS) in order to optimize their nanoporous structure toward optical sensors with enhanced sensing performance. Finally, we demonstrate the applicability of these photonic nanostructures as optical platforms by selectively detecting gold(iii) ions in aqueous solutions. The obtained results reveal that optimized NAA-DBR photonic coatings can achieve an outstanding sensing performance for gold(iii) ions, with a sensitivity of 22.16 nm μM-1, a low limit of detection of 0.156 μM (i.e. 30.7 ppb) and excellent linearity within the working range (0.9983).Herein, we present a systematic study on the development, optical optimization and sensing applicability of colored photonic coatings based on nanoporous anodic alumina films grown on aluminum substrates. These optical nanostructures, so-called distributed Bragg reflectors (NAA-DBRs), are fabricated by galvanostatic pulse anodization process, in which the current density is altered in a periodic manner in order to engineer the effective medium of the resulting

  11. 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

  12. Optics and multilayer coatings for EUVL systems

    SciTech Connect

    Soufli, R; Bajt, S; Hudyma, R M; Taylor, J S

    2008-03-21

    EUV lithography (EUVL) employs illumination wavelengths around 13.5 nm, and in many aspects it is considered an extension of optical lithography, which is used for the high-volume manufacturing (HVM) of today's microprocessors. The EUV wavelength of illumination dictates the use of reflective optical elements (mirrors) as opposed to the refractive lenses used in conventional lithographic systems. Thus, EUVL tools are based on all-reflective concepts: they use multilayer (ML) coated optics for their illumination and projection systems, and they have a ML-coated reflective mask.

  13. Defect-related properties of optical coatings

    NASA Astrophysics Data System (ADS)

    Cheng, Xinbin; Wang, Zhanshan

    2014-02-01

    Defects in optical coatings are a major factor degrading their performance. Based on the nature of defects, we classified them into two categories: visible defects and non-visible defects. Visible defects result from the replication of substrate imperfections or particulates within the coatings by subsequent layers and can increase scattering loss, produce critical errors in extreme ultraviolet lithography, weaken mechanical and environmental stability, and reduce laser damage resistance. Non-visible defects mainly involve a decrease in laser damage resistance but typically have no influence on other properties of optical coatings. In the case of widely used HfO2/SiO2 dielectric coatings, metallic Hf nano-clusters, off-stoichiometric HfO2 nano-clusters, or areas of high-density electronic defects have been postulated as possible sources for non-visible defects. The emphasis of this review is devoted to discussing localized defect-driven laser-induced damage (LID) in optical coatings used for nanosecond-scale pulsed laser applications, but consideration is also given to other properties of optical coatings such as scattering, environmental stability, etc. The low densities and diverse properties of defects make the systematic study of LID initiating from localized defects time-consuming and very challenging. Experimental and theoretical studies of localized defect-driven LID using artificial defects whose properties can be well controlled are highlighted.

  14. Characterization of 1064nm laser-induced damage on antireflection coatings grown by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Liu, Zhichao; Wei, Yaowei; Chen, Songlin; Luo, Jin; Ma, Ping

    2011-12-01

    Damage tests were carried out to measure the laser resistance of Al2O3/TiO2 and Al2O3/HfO2 antireflection coatings at 1064nm grown by atomic layer deposition (ALD). The S-on-1 and R-on-1 damage results are given. It's interesting to find that ALD coatings damage performance seems closed to those grown by conventional e-beam evaporation process. For Al2O3/TiO2 coatings, the grown temperature will impact the damage resistance of thin films. Crystallization of TiO2 layer at higher temperature could play an importance role as absorption defects that reduced the LIDT of coatings. In addition, it is found that using inorganic compound instead of organic compound as precursors for ALD process can effective prevent residual carbon in films and will increase the LIDT of coatings.

  15. The early days of optical coatings

    NASA Astrophysics Data System (ADS)

    Macleod, Angus

    1999-12-01

    The history of optical coatings is a long one with many observations and publications but little industrial activity until a period of explosive growth began in the 1940s. The trigger was World War II and the need on all sides for improved optical instruments ranging from binoculars to periscopes and bombsights, but it is certain that the growth would have occurred, perhaps a year or two later, even without the war. After the war the growth continued, partly because of military needs, but much more because of other factors such as the continuing growth in general optics, the enormous expansion of the chemical industry and its need for infrared and visible analytical tools, the need for narrowband contrast enhancing filters in astronomy, and then, very significantly, the laser. Nowadays, optical coatings are indispensible features of virtually all optical systems.

  16. Figure correction of multilayer coated optics

    DOEpatents

    Chapman; Henry N. , Taylor; John S.

    2010-02-16

    A process is provided for producing near-perfect optical surfaces, for EUV and soft-x-ray optics. The method involves polishing or otherwise figuring the multilayer coating that has been deposited on an optical substrate, in order to correct for errors in the figure of the substrate and coating. A method such as ion-beam milling is used to remove material from the multilayer coating by an amount that varies in a specified way across the substrate. The phase of the EUV light that is reflected from the multilayer will be affected by the amount of multilayer material removed, but this effect will be reduced by a factor of 1-n as compared with height variations of the substrate, where n is the average refractive index of the multilayer.

  17. Innovative multilayer coated optics for Solar Physics

    NASA Astrophysics Data System (ADS)

    Meltchakov, Evgueni; Auchere, Frederic; Delmotte, Franck; De Rossi, Sebastien; Mercier, Raymond; Zhang, Xueyan

    Development of multilayer coated optics with specific spectral characteristics and enhanced temporal, thermal and radiation stability requires an innovative approach to the design of reflecting multilayers and optimization of the coating process. Here we report on the progress in design, calculations and fabrication of reflecting multilayer coatings for solar imaging in the extreme ultra-violet (EUV) range. We will present recent results of characterization of new tri-component periodic multilayer structures containing aluminum as a low absorbing material within the spectral range from 17 to 40 nm. The EUV peak reflectance of these coatings (for instance, the Al/Mo/SiC multilayers) reaches 56% at 17.4 nm and 42% at 30 nm, highest reported up to now for these wavelengths. We have studied the temporal and thermal stability of structural and optical parameters of Al-based multilayer coatings as well as the resistivity of the coatings to high-energy and high-dose proton irradiation. A special attention will be drawn to specific bi-periodic systems with enhanced selectivity, which possess two efficient reflection bands and attenuate some unwanted emission lines in the EUV range. Experimental results show that such multilayer coatings are good candidates for the EUV imaging telescopes of Solar Orbiter and future solar missions.

  18. High performance fluoride optical coatings for DUV optics

    NASA Astrophysics Data System (ADS)

    Zhang, Lichao; Cai, Xikun

    2014-08-01

    In deep ultraviolet region that typical applications are used on the ArF wavelength, coated optics should meet stringent requirements of optical systems. To meet these requirements, systematical researches are carried out on fabrication and characterization methods of fluoride coatings. First, by optimizing of deposition processes, dense coatings with the refractive index of ~1.7 for LaF3 and ~1.4 for MgF2, together with extinction coefficients of ~2×10-4 on 193nm were realized. The transmission of AR coating for 193nm achieved by using optimized deposition techniques is 99.8%. Second, a method of designing shadowing masks was developed to solve the problem of correcting coating thickness distributions for complex DUV systems. By using the method, the thickness distribution error specification of 3% PV has been achieved on substrates with ~300mm diameters and large curvatures. Finally, the laser calorimetry method is used to evaluate the laser radiation stability of fluoride coatings. It is turned out that the damage coefficients of fluoride coatings, which are defined as the values of unrecoverable increase of the absorption during the laser irradiation process, are much lower than that of fused silica substrates. The above progresses could further support the realization of high performance DUV optical systems.

  19. Optical interference coatings prepared from solution.

    PubMed

    Phillips, R W; Dodds, J W

    1981-01-01

    Recently E. M. Laboratories introduced colloidal silica and titania solutions from which one can produce optical thin films. Single quarterwave V-coats and three-layer AR coatings for the visible as well as four-and five-layer AR coatings at 1.06 microm were prepared using these solutions. Reflection spectra and ellipso-metric measurements showed that these films are essentially optically equivalent to those prepared by e-beam evaporation. However, the former films lacked the rub durability of the latter films. This deficiency was traced by frustrated multiple internal reflectance (FMIR) spectroscopy and by Auger electron spectroscopy (AES) to organic solvents trapped within the titania matrix. X-ray diffraction (XRD) showed the silica films to be amorphous whereas the titania films were slightly crystalline with the anatase structure.

  20. Optical coating technology for the EUV

    NASA Technical Reports Server (NTRS)

    Osantowski, J. F.; Keski-Kuha, R. A. M.; Herzig, H.; Toft, A. R.; Gum, J. S.; Fleetwood, C. M.

    1991-01-01

    Advances in optical coating and materials technology are one of the key motivators for the development of missions such as the Far Ultraviolet Spectroscopic Explorer recently selected by NASA for an Explorer class mission in the mid 1990's. The performance of a range of candidate coatings are reviewed for normal-incidence and glancing-incidence applications, and attention is given to strengths and problem areas for their use in space. The importance of recent developments in multilayer films, chemical-vapor deposited SiC (CVD-SiC) mirrors, and SiC films are discussed in the context of EUV instrumentation design. For example, the choice of optical coatings is a design driver for the selection of the average glancing angle for the FUSE telescope, and impacts efficiency, short-wavelength cut-off, and physical size.

  1. The Discovery Channel Telescope optical coating system

    NASA Astrophysics Data System (ADS)

    Marshall, Heather K.; Ash, Gary S.; Parsley, William F.

    2010-07-01

    The Discovery Channel Telescope (DCT) is a project of Lowell Observatory, undertaken with support from Discovery Communications, Inc., to design and construct a 4-meter class telescope and support facility on a site approximately 40 miles southeast of Flagstaff, AZ. Lowell Observatory contracted with Dynavac of Hingham, MA to design and build an optical coating system for the DCT optics. The DCT Optical Coating System includes a mechanical roughing pump, two high-vacuum cryogenic pumps, a Meissner trap, evaporative filament aluminum deposition system, LabView software and PLC-based control system, and all ancillary support equipment. The system was installed at the site and acceptance testing was completed in October 2009. The Optical Coating System achieved near perfect reflectivity performance, thickness uniformity of 1000 angstroms +/-10%, and adhesion conforming to MIL-F-48616, Section 4.6.8.1. This paper discusses the design and analysis of the coating system, the process of transportation and assembly as well as testing results.

  2. Correlation between bioactivity and structural properties of titanium dioxide coatings grown by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Grigal, I. P.; Markeev, A. M.; Gudkova, S. A.; Chernikova, A. G.; Mityaev, A. S.; Alekhin, A. P.

    2012-02-01

    TiO2 coatings were grown on Ti and Si by Atomic Layer Deposition (ALD) from titanium ethoxide and water at 300 °C in a wide range of the reaction cycles number N = 100-2000. TiO2 coatings were found to be amorphous at low value of N < 300 while the coatings grown at N ≥ 300 revealed anatase polycrystalline structure. The TiO2 coatings bioactivity was evaluated by hydroxyapatite forming ability by the technique of soaking in Simulated Body Fluid (SBF). Correlation between bioactivity and structural properties of TiO2 was determined. X-ray diffraction and scanning electron microscopy with electron probe microanalysis showed that amorphous TiO2 coating did not induce the hydroxyapatite growth whereas anatase resulted in the hydroxyapatite forming on the samples surfaces which confirmed TiO2 anatase bioactivity.

  3. Ultrasonic characterization of thermally grown oxide in thermal barrier coating by reflection coefficient amplitude spectrum.

    PubMed

    Ma, Zhiyuan; Zhao, Yang; Luo, Zhongbing; Lin, Li

    2014-04-01

    The thermally grown oxide (TGO) growth at the interface of ceramic coating/bond coating in thermal barrier coatings (TBCs) was evaluated by ultrasonic reflection coefficient amplitude spectrum (URCAS). A theoretical analysis was performed about the influence of acoustic impedance match relationship between the ceramic coating and its adjacent media on URCAS. The immersion ultrasonic narrow pulse echo method was carried out on the TBC specimen before and after oxidation under 1050°C×1h for 15cycles. The resonant peaks of URCAS obtained before and after oxidation showed that TGO which generated between the ceramic coating and bond coating due to the oxidation, changed the acoustic impedance match between the ceramic coating and its adjacent media. This method is able to nondestructively characterize the generation of TGO in TBCs, and is important to practical engineering application.

  4. The optical properties of hygroscopic soot aggregates with water coating

    NASA Astrophysics Data System (ADS)

    Wu, Yu; Cheng, Tianhai; Zheng, Lijuan

    2014-05-01

    Anthropogenic aerosols, such as soot, have modified the Earth's radiation balance by scattering and absorbing solar and long-wave radiative transmission, which have largely influenced the global climate change since the industrial era. Based on transmission electron microscope images (TEM), soot particles are shown as the complex, fractal-like aggregate structures. In humid atmospheric environments, these soot aggregates tend to acquire a water coating, which introduces further complexity to the problem of determining the optical properties of the aggregates. The hygroscopic growth of soot aggregates is important for the aging of these absorbing aerosols, which can significantly influence the optical properties of these kinds of soot particles. In this paper, according to the specific volume fractions of soot core in the water coated soot particle, the monomers of fractal soot aggregates are modeled as semi-external mixtures (physical contact) with constant radius of soot core and variable size of water coating. The single scattering properties of these hygroscopic soot particles, such as scattering matrices, the cross sections of extinction, absorption and scattering, single scattering albedo (SSA), and asymmetry parameter (ASY), are calculated using the numerically exact superposition T-matrix method. The morphological effects are compared with different monomer numbers and fractal dimensions of the soot aggregates, as well as different size of water coating for these concentric spherical monomers. The results have shown that SSA, cross sections of extinction and absorption are increased for soot aggregates with thicker weakly absorbing coating on the monomers. It is found that the SSA of aged soot aggregates with hygroscopic grown are remarkably (~50% for volume fraction of soot aggregates is 0.5, at 0.670μm) larger than fresh soot particles without the consideration of water coating, due to the size of water coating and the morphological features, such as the

  5. New sputtering concept for optical precision coatings

    NASA Astrophysics Data System (ADS)

    Rademacher, Daniel; Bräuer, Günter; Vergöhl, Michael; Fritz, Benjamin; Zickenrott, Tobias

    2011-09-01

    The deposition of optical precision coatings on glass by magnetron sputtering is still a challenging problem regarding particle density and long term stability of coating plants due to target material erosion. A novel approach to increase process stability and reduce drifts is the usage of cylindrical cathodes. These cathodes allow a particle free deposition process as they have virtually no redeposition zones that can lead to destruction of coatings by arcing caused by surface charges. In the present paper optical single layers as well as multilayer coatings were sputtered by means of reactive magnetron sputtering using a double cylindrical cathode setup. The particle density is determined and compared to particles produced with planar magnetrons. A new sputter coater concept will be presented wherein the magnetrons are attached to a rotating disc coater in a sputter-up configuration. The process was stabilized by means of oxygen partial pressure control. Preliminary optical properties as well as deposition rates of different oxide films will be presented.

  6. Coated fiber tips for optical instrumentation

    NASA Astrophysics Data System (ADS)

    Barton, John B.; Chanda, Sheetal; Locknar, Sarah A.; Carver, Gary E.

    2016-03-01

    Compact optical systems can be fabricated by integrating coatings on fiber tips. Examples include fiber lasers, fiber interferometers, fiber Raman probes, fiber based spectrometers, and anti-reflected endoscopes. These interference filters are applied to exposed tips - either connectorized or cleaved. Coatings can also be immersed within glass by depositing on one tip and connecting to another uncoated tip. This paper addresses a fiber spectrometer for multispectral imaging - useful in several fields including biomedical scanning, flow cytometry, and remote sensing. Our spectrometer integrates serial arrays of reflecting fiber tips, delay lines between these elements, and a single element detector.

  7. New Challenges in Optical Coating Design

    NASA Astrophysics Data System (ADS)

    Stenzel, Olaf

    Modern mathematical algorithms allow to theoretically generate thin film designs that fit nearly any reasonable specification. Nevertheless, as practice has shown, the gap between calculated and technologically achievable characteristics may be significant, so that the search for qualitatively new design and production tools is still in progress and represents one of the most complex challenges in thin optical coating theory and technology today. Such new design challenges include the incorporation of gradient index layers into classical designs, the design of rugate filters, or novel filter concepts that are based on resonant grating waveguide structures. Moreover, the development of novel composite coating materials is expected to facilitate the optimisation of future designs.

  8. Coherent Optical Adaptive Techniques (COAT)

    DTIC Science & Technology

    1973-02-01

    E o U rt UJ c t- 3 c o ■p t) c u •H +» ft o \\ o •d H & ■H to ■ o 10 ..,. J,.-. ..»^-^A^.^-. mfiiTflMaaj— ft ! -^^ lUMI IJI...13) 2 2 2 J,(Tidp) array r n=-oo e e ^ a Jl( XR ^o +yo j o vo E 5 n--ae 0 n\\/-N , TTD XB - i 0 sinc XR Xo ( ft ...was found that the acousto-optic Bragg cell functioning as a frequency modulator can meet the unlimited dynamic range and bandwidth requirements

  9. Laser Window Materials and Optical Coating Science

    DTIC Science & Technology

    1977-08-01

    10 Torr pressure , is presently the favored alternative RAP agent. Comparison studies of optical coatings prepared under conventional high...In principle , the uncoated surface heat also contributes to the first and second slopes but in practice, as discussed in the results in Sec. Ill...jim), CO (5.3 jim), and CO2 (9.27 and 10.6 fi.m). The window materials that are under investigation include selected alkali halides and

  10. Optical Diagnostics for Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Eldridge, J. I.; Spuckler, C. M.; Bencic, T. J.; Martin, R. E.

    2004-01-01

    The translucent nature of ceramic oxide thermal barrier coatings (TBCs) provides an opportunity to employ optical probes to monitor temperature gradients and buried damage propagation within the coating. An important advantage of noncontact optical diagnostics is that they are amendable to health monitoring of TBCs in service. In this paper, two optical diagnostic approaches, operating in different wavelength regimes, are discussed. The first approach is the use of mid-infrared reflectance (MIR) to monitor the progression of TBC delamination produced by thermal cycling. This approach takes advantage of the maximum transparency of the TBCs at mid-infrared wavelengths, in particular, between 3 and 5 microns. Recent progress in extending the MIR method to a more practical visual inspection tool will be presented. A second approach, using visible wavelengths, is the embedding of thermographic phosphors within the TBC to add sensing functions to the coating that can provide depth-selective information about temperature gradients and TBC integrity. Emphasis will be given to the use of fluorescence decay time measurements to provide temperature readings from a thermographic phosphor layer residing beneath the TBC.

  11. Optical Society of America's 2007 Topical Meeting on Optical Interference Coatings: overview.

    PubMed

    Kaiser, Norbert; Stolz, Christopher J

    2008-05-01

    The Optical Society of America's Topical Meeting on Optical Interference Coatings convenes every three years to survey and capture advancements in the broad area of optical coatings. This meeting serves as a focal point for global technical interchange in the field of optical interference coatings. It includes papers on research, development, and applications of optical coatings, such as fundamental and theoretical contributions in the field as well as practical techniques and applications.

  12. High-temperature polyimide coating for optical fibres

    SciTech Connect

    Semjonov, S L; Dianov, E M; Sapozhnikov, D A; Erin, D Yu; Zabegaeva, O N; Kushtavkina, I A; Vygodskii, Ya S; Nishchev, K N

    2015-04-30

    We present our first results on the fabrication of new, high-performance polyimide coatings. The key components of the coatings are polyimides containing various cardo and/or fluoroalkylene groups, which allows the coatings to retain their high-temperature stability and facilitates the storage of the starting polymer and the optical fibre coating process owing to the good solubility of such copolymers in many organic solvents. Annealing for 30 s, 1 h and 24 h at temperatures of 430, 350 and 300 °C, respectively, reduces the strength of optical fibres having such coating by no more than 10%. (optical fibres)

  13. Design and testing of AR coatings for MEGARA optics

    NASA Astrophysics Data System (ADS)

    Ortiz, R.; Carrasco, E.; Páez, G.; Pompa, O.; Sanchez-Blanco, E.; Gil de Paz, A.; Gallego, J.; Iglesias-Páramo, J.

    2016-08-01

    We present the antireflection coatings of the optical elements of MEGARA, the new integral field and multi-object spectrograph for the Gran Telescopio Canarias. We describe the methodology for optimizing the solutions. We also present the results of the final deposited coatings. The main optics require broadband coatings in the range from 370 nm to 980 nm for different materials with a mean R<1.3% at specific angles of incidence in each surface. For each material a specific arrangement of thicknesses of the same eight layers were produced and tested. For the spectrograph pupil elements four layer coatings were designed and produced R<0.3%. The design of main optics and pupil elements coatings have been shared between INAOE and CIO. The coating depositions have been performed at CIO in the Integrity 39 Denton Vacuum Deposition System. The main optics final coatings fulfill MEGARA requirements.

  14. Optical reflector coatings for astronomical applications from EUV to IR

    NASA Astrophysics Data System (ADS)

    Schürmann, Mark; Jobst, Paul Johannes; Yulin, Sergiy; Feigl, Torsten; Heiße, Hanno; Wilbrandt, Steffen; Stenzel, Olaf; Gebhardt, Andreas; Risse, Stefan; Kaiser, Norbert

    2012-09-01

    Optical coatings are an integral part of superior optical components. Astronomical applications (ground- and space-based) place especially high demands on these coatings, not only with regard to their optical performance but also to their mechanical and environmental stability, their thermal properties, and their radiation resistance. This article presents a short overview of several coating solutions developed in recent years at Fraunhofer IOF in order to meet the challenging demands of astronomical applications. The focus is placed on high reflective coatings for different wavelength regions including coatings for the VUV range below 100nm, coatings for the DUV wavelength range above 100nm and VIS/NIR/IR coatings. Further, amorphous silicon layers will be introduced which can be polished to very low roughness values and therefore can act as polishing layer for the manufacture of ultraprecise optical components from metal substrates.

  15. Maintaining high-Q in an optical microresonator coated with high-aspect-ratio gold nanorods

    NASA Astrophysics Data System (ADS)

    Ganta, D.; Dale, E. B.; Rosenberger, A. T.

    2013-10-01

    We report methods to coat fused-silica microresonators with solution-grown high-aspect-ratio (AR) gold nanorods (NRs). Microresonators coated using our method maintain an optical quality factor (Q) greater than 107 after coating. The more successful method involves silanization of the surface of the microresonator with 3-mercaptopropylmethyldimethoxysilane (MPMDMS), to enable the adhesion of gold NRs. The high-AR NR-coated microresonator combines the field enhancement of localized surface plasmon resonances with the cavity-enhanced evanescent components of high-Q whispering-gallery modes, making it useful for plasmonic sensing applications in the infrared. By coating with NRs having a different aspect ratio, the enhancement regime can be selected within a wide range of wavelengths.

  16. Diamondlike carbon protective coatings for optical windows

    NASA Technical Reports Server (NTRS)

    Swec, Diane M.; Mirtich, Michael J.

    1989-01-01

    Diamondlike carbon (DLC) films were deposited on infrared transmitting optical windows and were evaluated as protective coatings for these windows exposed to particle and rain erosion. The DLC films were deposited on zinc selenide (ZnSe) and zinc sulfide (ZnS) by three different ion beam methods: (1) sputter deposition from a carbon target using an 8-cm argon ion source; (2) direct deposition by a 30-cm hollow cathode ion source with hydrocarbon gas in argon; and (3) dual beam direct deposition by the 30-cm hollow cathode ion source and an 8-cm argon ion source. In an attempt to improve the adherence of the DLC films on ZnSc and ZnS, ion beam cleaning, ion implantation with helium and neon ions, or sputter deposition of a thin, ion beam intermediate coating was employed prior to deposition of the DLC film. The protection that the DLC films afforded the windows from particle and rain erosion was evaluated, along with the hydrogen content, adherence, intrinsic stress, and infrared transmittance of the films. Because of the elevated stress levels in the ion beam sputtered DLC films and in those ion beam deposited with butane, films thicker than 0.1 micron and with good adherence on ZnS and ZnSe could not be generated. An intermediate coating of germanium successfully allowed the DLC films to remain adherent to the optical windows and caused only negligible reduction in the specular transmittance of the ZnS and ZnSe at 10 microns.

  17. Multilayer optical interference coatings via glow discharge polymerization techniques.

    PubMed

    Lee, J C

    1978-08-15

    The incorporation of an optical-thickness monitor in the plasma reactor allows the fabrication of well tuned multilayer optical interference coatings, the variety and application range of which is constrained only by the limited number of presently known well characterized plasma polymers. The properties and deposition idiosyncracies of several plasma polymers found useful for optical thin films are discussed, and optical performance data for specific beam splitter and antireflection coating designs fabricated from available materials are presented.

  18. Method for forming hermetic coatings for optical fibers

    DOEpatents

    Michalske, Terry A.; Rye, Robert R.; Smith, William L.

    1993-01-01

    A method for forming hermetic coatings on optical fibers by hot filament assisted chemical vapor deposition advantageously produces a desirable coating while maintaining the pristine strength of the pristine fiber. The hermetic coatings may be formed from a variety of substances, such as, for example, boron nitride and carbon.

  19. Optical parameters of boron-doped ZnO nanorods grown by low-temperature hydrothermal reaction.

    PubMed

    Kim, Soaram; Park, Hyunggil; Nam, Giwoong; Yoon, Hyunsik; Kim, Younggyu; Kim, Byunggu; Ji, Iksoo; Kim, Jong Su; Kim, Jin Soo; Kim, Do Yeob; Kim, Sung-O; Leem, Jae-Young

    2014-11-01

    Sol-gel spin-coating was used to deposit ZnO seed layers onto quartz substrates, and ZnO nanorods doped with various concentrations of B (i.e., BZO nanorods) ranging from 0 to 2.0 at% were hydrothermally grown on the ZnO seed layers. The effects of B doping on the absorption coefficient, optical band gap, Urbach energy, refractive index, extinction coefficient, single-oscillator energy, dispersion energy, average oscillator strength, average oscillator wavelength, dielectric constant, and optical conductivity of the hydrothermally grown BZO nanorods were investigated. The optical band gaps were 3.255, 3.243, 3.254, 3.258, and 3.228 eV for the nanorods grwon at 0, 0.5, 1.0, 1.5 and 2.0 at% B, respectively. B doping increased the Urbach energy from 40.7 to 65.1 meV for the nanorods grown at 0 and 2.0 at% B, respectively, and significantly affected the dispersion energy, the single-oscillator energy, the average oscillator wavelength, the average oscillator strength, the refractive index, and the optical conductivity of the hydrothermally grown BZO nanorods.

  20. Simple method for measuring reflectance of optical coatings

    SciTech Connect

    Wen Gui Wang; Yi Sheng Chen

    1995-12-31

    The quality of optical coatings has an important effect on the performance of optical instrument. The last few years, the requirements for super low loss dielectric mirror coatings used in low gain laser systems such as free electron laser and the ring laser etc., have given an impetus to the development of the technology of precise reflectance measurement of optical coatings. A reliable and workable technique is to measure the light intensity decay time of optical resonant cavity. This paper describes a measuring method which is dependent on direct measurement of the light intensity decay time of a resonant cavity comprised of low loss optical components. According to the evolution of a luminous flux stored inside the cavity, this method guarantees not only a quick and precise reflectance measurements of low loss highly reflecting mirror coatings but also transmittance measurements of low loss antireflection coatings and is especially effective with super los loss highly reflecting mirror. From the round-trip path length of the cavity and the speed of light, the light intensity exponential decay time of an optical cavity is easy to obtain and the cavity losses can be deduced. An optical reflectance of low loss highly mirror coatings and antireflection coatings is precisely measured as well. This is highly significant for the discrimination of the coating surface characteristics, the improvement of the performance of optical instrument and the development of high technology.

  1. James Webb Space Telescope Optical Telescope Element Mirror Coatings

    NASA Technical Reports Server (NTRS)

    Keski-Kuha, Ritva A.; Bowers, Charles W.; Quijada, Manuel A.; Heaney, James B.; Gallagher, Benjamin; McKay, Andrew; Stevenson, Ian

    2012-01-01

    James Webb Space Telescope (JWST) Optical Telescope Element (OTE) mirror coating program has been completed. The science goals of the JWST mission require a uniform, low stress, durable optical coating with high reflectivity over the JWST spectral region. The coating has to be environmentally stable, radiation resistant and compatible with the cryogenic operating environment. The large size, 1.52 m point to point, light weight, beryllium primary mirror (PM) segments and flawless coating process during the flight mirror coating program that consisted coating of 21 flight mirrors were among many technical challenges. This paper provides an overview of the JWST telescope mirror coating program. The paper summarizes the coating development program and performance of the flight mirrors.

  2. Optical properties of undoped and Al-doped ZnO nanostructures grown from aqueous solution on glass substrate

    NASA Astrophysics Data System (ADS)

    Mazilu, M.; Tigau, N.; Musat, V.

    2012-09-01

    The paper presents the optical properties of undoped and aluminium-doped zinc oxide nanostructures grown on glass substrates using the hydrothermal method. The obtained ZnO-based nanostructures showed optical transmittance over 75% and low reflectance in the visible domain. The increasing of optical transmittance of Al-doped ZnO nanostructures with increased doping concentrations was observed. The optical constants such as index of refraction, extinction coefficient, dielectric constants and optical conductivity were determined using the transmission and the reflection at normal incidence of light in the wavelength range of 200-1100 nm. The band gap broadens with increasing dopant concentration from 2% to 4%. The obtained nanostructured layers with size in the range of subwavelength of visible light can act as anti-reflective coating that reduces reflectance based on the Moth Eye principle.

  3. Optical interference coatings for improved luminaire performance. Final report

    SciTech Connect

    Rubins, H.L.

    1981-01-01

    An interior broadbeam HID uplight and an upstream roadway luminaire were developed to demonstrate that optical coated luminaire components can improve the visual effectiveness and energy efficiency of a lighting system. Optical coated reflectors and flat lens covers were very effective in the development of new improved lighting techniques. The coatings reduce reflection and transmission losses, opening the door to new design options for improving lighting performance and saving energy.

  4. Metal-Coated Optical Fibers for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Zeakes, Jason; Murphy, Kent; Claus, Richard; Greene, Jonathan; Tran, Tuan

    1996-01-01

    This poster will highlight on-going research at the Virginia Tech Fiber & Electro-Optics Research Center (FEORC) in the area of thin films on optical fibers. Topics will include the sputter deposition of metals and metal; alloys onto optical fiber and fiber optic sensors for innovative applications. Specific information will be available on thin film fiber optic hydrogen sensors, corrosion sensors, and metal-coated optical fiber for high temperature aerospace applications.

  5. Self-cleaning antireflective optical coatings.

    PubMed

    Guldin, Stefan; Kohn, Peter; Stefik, Morgan; Song, Juho; Divitini, Giorgio; Ecarla, Fanny; Ducati, Caterina; Wiesner, Ulrich; Steiner, Ullrich

    2013-01-01

    Low-cost antireflection coatings (ARCs) on large optical surfaces are an ingredient-technology for high-performance solar cells. While nanoporous thin films that meet the zero-reflectance conditions on transparent substrates can be cheaply manufactured, their suitability for outdoor applications is limited by the lack of robustness and cleanability. Here, we present a simple method for the manufacture of robust self-cleaning ARCs. Our strategy relies on the self-assembly of a block-copolymer in combination with silica-based sol-gel chemistry and preformed TiO2 nanocrystals. The spontaneous dense packing of copolymer micelles followed by a condensation reaction results in an inverse opal-type silica morphology that is loaded with TiO2 photocatalytic hot-spots. The very low volume fraction of the inorganic network allows the optimization of the antireflecting properties of the porous ARC despite the high refractive index of the embedded photocatalytic TiO2 nanocrystals. The resulting ARCs combine high optical and self-cleaning performance and can be deposited onto flexible plastic substrates.

  6. Study of influence of the fiber optic coatings parameters on optical acoustic sensitivity

    NASA Astrophysics Data System (ADS)

    Lavrov, V. S.; Kulikov, A. V.; Plotnikov, M. U.; Efimov, M. E.; Varzhel, S. V.

    2016-08-01

    The paper presents the optical fiber acoustic sensitivity dependence on the coating parameters and the thickness of coating layer. A comparison of data obtained from the theoretical research and experimental estimates of real samples sensitivity in air and water.

  7. Effect of coated urea on cadmium accumulation in Oryza sativa L. grown in contaminated soil.

    PubMed

    Xu, Chao; Wu, Zisong; Zhu, Qihong; Zhu, Hanhua; Zhang, Yangzhu; Huang, Daoyou

    2015-11-01

    Experiments were conducted to determine the effects of three types of coated urea on the accumulation of cadmium (Cd) in rice (Oryza sativa L.) grown in contaminated soil. Pot-culture experiments were conducted in a greenhouse from July to November 2012 on the rice cultivar "Hua Hang Si Miao" in Guangzhou (China). The experimental design was completely randomized with four treatments and three replications. The treatments were control (CK) (N 0 mg/kg), prilled urea (PU) (N 200 mg/kg), polymer-coated urea (PCU) (N 200 mg/kg), and sulfur-coated urea (SCU) (N 200 mg/kg). Our results indicated that applications of PCU and SCU slightly increased the dry weight of rice grains. The application of SCU significantly decreased the CaCl2 and toxicity characteristic leaching procedure (TCLP)-extractable Cd concentrations by 15.4 and 56.1%, respectively. Sequential extractions showed that PCU and SCU applications led to a significant decrease in Cd in the exchangeable fraction and an increase in the bound iron (Fe) and manganese (Mn) oxides fractions. Cd concentrations in grains treated with PCU were reduced by 11.7%, whereas SCU significantly reduced Cd concentrations by 29.1%. SCU reduced Cd transfer from the straws to the grain. Our results demonstrated that PCU and SCU may be effective in mitigating Cd accumulation in rice grown in acidic Cd-contaminated soil, especially in plants receiving SCU.

  8. Optical properties of metal oxynitride thin films grown with atmospheric plasma deposition

    NASA Astrophysics Data System (ADS)

    Hovish, Michael Q.; Dauskardt, Reinhold H.

    2016-10-01

    Thin films of tantalum oxynitride (TaO x N y ) and titanium oxynitride (TiO x N y ) are deposited using atmospheric plasma deposition and a suite of optical properties are reported. Tantalum and titanium ethoxide are introduced into the afterglow of a radio-frequency capacitively coupled plasma, facilitating the growth of oxynitride films on silicon and polycarbonate at temperatures below 180 °C. The plasma power and nitrogen flow within the plasma are varied between 60 and 120 W and between 0.1 and 0.3 LPM respectively. We use spectroscopic ellipsometry to show that the optical properties of the metal oxynitride films grown in this study are comparable to those synthesized with sol-gel methods. Measurement of both the extinction coefficient and the transmission on polycarbonate substrates indicates good transparency in the visible wavelengths of light. Additionally, the refractive index increases when increasing the number of reactive nitrogen species within the discharge. We use x-ray photoelectron spectroscopy to correlate the higher indexes observed at large secondary gas flows to the presence of metal oxynitride bonding. Single layer anti-reflection coatings are deposited on silicon, with a five-fold and seven-fold reduction in reflection for TaO x N y and TiO x N y coatings, respectively. In total, we have found that the modulation of nitrogen concentration within the plasma discharge results in good control over optical constants. In addition, we observe similarities between films deposited with atmospheric plasma and those reported for sol-gel, indicating an alternative processing route where solution chemistries are currently applied.

  9. Acousto-optic interaction in polyimide coated optical fibers with flexural waves.

    PubMed

    Alcusa-Sáez, E P; Díez, A; Rivera-Pérez, E; Margulis, W; Norin, L; Andrés, M V

    2017-07-24

    Acousto-optic coupling in polyimide-coated single-mode optical fibers using flexural elastic waves is demonstrated. The effect of the polyimide coating on the acousto-optic interaction process is analyzed in detailed. Theoretical and experimental results are in good agreement. Although the elastic attenuation is significant, we show that acousto-optic coupling can be produced with a reasonably good efficiency. To our knowledge, it is the first experimental demonstration of acousto-optic coupling in optical fibers with robust protective coating.

  10. Interference Lithography for Optical Devices and Coatings

    DTIC Science & Technology

    2010-01-01

    fabricate self- healing coatings that use water from the environment to catalyze polymerization. Polymerization induced phase separation was used to... catalyzed by moisture in air; if the indices of the two polymers are matched, the coatings turn transparent after healing. Interference lithography...self- healing coatings that use water from the environment to catalyze polymerization. Polymerization induced phase separation was used to sequester

  11. 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.

  12. Optimizing thermally grown oxide for thermal barrier coatings on TiAl components via fluorine treatment

    NASA Astrophysics Data System (ADS)

    Donchev, A.; Braun, R.; Schütze, M.

    2010-01-01

    Titanium aluminides suffer from non-protective mixed-oxide scale formation during high-temperature exposure in oxidizing environments, so that they cannot be used at temperatures above approximately 800° C for longer times without additional treatment. A fluorine treatment on γ-TiAl alloys leads to the formation of a pure protective alumina scale and allows their use at service temperatures above 800°C. This thermally grown aluminum oxide layer can be used for bonding ceramic thermal barrier coatings to the TiAl substrate. Zirconia topcoats deposited by electron-beam physical vapor deposition were very adherent to F-treated TiA samples during cyclic oxidation tests at 900 to 1,000°C. A separate bond coat is not needed in this case.

  13. A novel processing of carbon nanotubes grown on molecular sieve coated porous ceramics

    NASA Astrophysics Data System (ADS)

    Mazumder, Sangram; Sarkar, Naboneeta; Park, Jung Gyu; Zhao, Wei; Kim, Sukyoung; Kim, Ik Jin

    2015-08-01

    The present study focuses on the growth of carbon nanotubes (CNTs) on Fe-containing zeolites coated porous ceramics by implementing three different and independent techniques, successively. Direct foaming-derived porous ceramics were subjected to hydrothermal reaction for on-site growth of NaA zeolites within it. The porous ceramics-zeolite composite was subjected to ion-exchange reaction to obtain the catalyst for CNT synthesis. Multi-walled CNTs (MWCNTs) were grown by catalytic chemical vapour deposition (CCVD) process using acetylene as carbon source. Microstructural, thermogravimetric and spectroscopic analyses showed distinctive differences in terms of hollow structural feature, yield and crystallinity of the MWCNTs with different reaction temperatures.

  14. Optical interference coatings: introduction by the feature editors.

    PubMed

    Macleod, H A; Thelen, A

    1989-07-15

    This introduction briefly reviews the history of the series of topical meetings on optical interference coatings and defines the scope of the features in this 15 July 1989 issue on the papers from the Fourth Topical Meeting.

  15. Fiber optic ultrasound transducers with carbon/PDMS composite coatings

    NASA Astrophysics Data System (ADS)

    Mosse, Charles A.; Colchester, Richard J.; Bhachu, Davinder S.; Zhang, Edward Z.; Papakonstantinou, Ioannis; Desjardins, Adrien E.

    2014-03-01

    Novel ultrasound transducers were created with a composite of carbon nanotubes (CNTs) and polydimethylsiloxane (PDMS) that was dip coated onto the end faces of optical fibers. The CNTs were functionalized with oleylamine to allow for their dissolution in xylene, a solvent of PDMS. Ultrasound pulses were generated by illuminating the composite coating with pulsed laser light. At distances of 2 to 16 mm from the end faces, ultrasound pressures ranged from 0.81 to 0.07 MPa and from 0.27 to 0.03 MPa with 105 and 200 μm core fibers, respectively. Using an optical fiber hydrophone positioned adjacent to the coated 200 µm core optical fiber, ultrasound reflectance measurements were obtained from the outer surface of a sheep heart ventricle. The results of this study suggest that ultrasound transducers that comprise optical fibers with CNT-PDMS composite coatings may be suitable for miniature medical imaging probes.

  16. Status of Optical Coatings for the National Ignition Facility

    SciTech Connect

    Stolz, C J; Weinzapfel, C; Rogowski, G T; Smith, D; Rigatti, A; Oliver, J; Taniguchi, J; von Gunten, M; Bevis, R; Smith, M; Ivan, V

    2001-03-05

    Optical coatings are a crucial part of the pulse trapping and extraction in the NIF multipass amplifiers. Coatings also steer the 192 beams from four linear arrays to four converging cones entering the target chamber. There are a total of 1600 physical vapor deposited coatings on NIF consisting of 576 mirrors within the multipass cavity, 192 polarizers that work in tandem with a Pockels cell to create an optical switch, and 832 transport mirrors. These optics are of sufficient size so that they are not aperture-limiting for the 40-cm x 40 cm beams over an incident range of 0 to 56.4 degrees. These coatings must withstand laser fluences up to 25 J/cm{sup 2} at 1053 nm (1 {omega}) and 3-ns pulse length and are the 1{omega} fluence-limiting component on NIF. The coatings must have a minimal impact on the beam wavefront and phase to maintain beam focusability, minimize scattered loss, and minimize nonlinear damage mechanisms. This is achieved by specifications ranging from <50 MPa coating stress, <1% coating nonuniformity, <4{angstrom} RMS surface roughness, and a PSD specification to control the amplitude of periodic spatial frequencies. Finally, the primary mission of optical coatings is efficient beam steering so reflection and transmission losses are specified as R>99.5% and >99% for mirrors and polarizers, respectively, and T>98% for polarizers.

  17. X-ray photoelectron spectroscopy study of the growth kinetics of biomimetically grown hydroxyapatite thin-film coatings

    NASA Astrophysics Data System (ADS)

    McLeod, K.; Kumar, S.; Dutta, N. K.; Smart, R. St. C.; Voelcker, N. H.; Anderson, G. I.

    2010-09-01

    Hydroxyapatite (HA) thin-film coatings grown biomimetically using simulated body fluid (SBF) are desirable for a range of applications such as improved fixation of fine- and complex-shaped orthopedic and dental implants, tissue engineering scaffolds and localized and sustained drug delivery. There is a dearth of knowledge on two key aspects of SBF-grown HA coatings: (i) the growth kinetics over short deposition periods, hours rather than weeks; and (ii) possible difference between the coatings deposited with and without periodic SBF replenishment. A study centred on these aspects is reported. X-ray photoelectron spectroscopy (XPS) has been used to study the growth kinetics of SBF-grown HA coatings for deposition periods ranging from 0.5 h to 21 days. The coatings were deposited with and without periodic replenishment of SBF. The XPS studies revealed that: (i) a continuous, stable HA coating fully covered the titanium substrate after a growth period of 13 h without SBF replenishment; (ii) thicker HA coatings about 1 μm in thickness resulted after a growth period of 21 days, both with and without SBF replenishment; and (iii) the Ca/P ratio at the surface of the HA coating was significantly lower than that in its bulk. No significant difference between HA grown with and without periodic replenishment of SBF was found. The coatings were determined to be carbonated, a characteristic desirable for improved implant fixation. The atomic force and scanning electron microscopies results suggested that heterogeneous nucleation and growth are the primary deposition mode for these coatings. Primary osteoblast cell studies demonstrated the biocompatibility of these coatings, i.e., osteoblast colony coverage of approximately 80%, similar to the control substrate (tissue culture polystyrene).

  18. Use of polyethylene glycol coatings for optical fibre humidity sensing

    NASA Astrophysics Data System (ADS)

    Acikgoz, Sabriye; Bilen, Bukem; Demir, Mustafa Muamer; Menceloglu, Yusuf Ziya; Skarlatos, Yani; Aktas, Gulen; Inci, Mehmet Naci

    2008-03-01

    Humidity induced change in the refractive index and thickness of the polyethylene glycol (PEG) coatings are in situ investigated for a range from 10 to 95%, using an optical waveguide spectroscopic technique. It is experimentally demonstrated that, upon humidity change, the optical and swelling characteristics of the PEG coatings can be employed to build a plastic fibre optic humidity sensor. The sensing mechanism is based on the humidity induced change in the refractive index of the PEG film, which is directly coated onto a polished segment of a plastic optical fibre with dip-coating method. It is observed that PEG, which is a highly hydrophilic material, shows no monotonic linear response to humidity but gives different characteristics for various ranges of humidity levels both in index of refraction and in thickness. It undergoes a physical phase change from a semi-crystalline structure to a gel one at around 80% relative humidity. At this phase change point, a drastic decrease occurs in the index of refraction as well as a drastic increase in the swelling of the PEG film. In addition, PEG coatings are hydrogenated in a vacuum chamber. It is observed that the hydrogen has a preventing effect on the humidity induced phase change in PEG coatings. Finally, the possibility of using PEG coatings in construction of a real plastic fibre optic humidity sensor is discussed.

  19. Optical monitoring for power law fluids during spin coating.

    PubMed

    Jardim, P L G; Michels, A F; Horowitz, F

    2012-01-30

    Optical monitoring is applied, in situ and in real time, to non-newtonian, power law fluids in the spin coating process. An analytical exact solution is presented for thickness evolution that well fits to most measurement data. As result, typical rheological parameters are obtained for several CMC (carboximetilcelullose) concentrations and rotation speeds. Optical monitoring thus precisely indicates applicability of the model to power law fluids under spin coating.

  20. Influence of high temperatures on optical fibers coated with multilayer protective coatings

    NASA Astrophysics Data System (ADS)

    Stanczyk, T.; Fidelus, J.; Wysokinski, K.; Lipinski, S.; Tenderenda, T.; Kuklińska, M.; Kołakowska, A.; Rodriguez Garcia, J.; Canadas Martinez, I.; Nasiłowski, T.

    2015-12-01

    In this work we present an innovative method of enhancing optical fibers' resistance to extremely high temperatures by deposition of a multilayer metal coating on the fibers' surface. Such multilayer coating is necessary because of the silica degradation at elevated temperatures. Despite the fact that copper coated fibers work well at temperatures up to 400°C, at higher temperatures copper oxidizes and can no longer protect the fiber. To hold back the copper oxidation and silica degradation processes we developed a dedicated multilayer coating which allows fibers to operate at temperatures up to 700°C. The optimal protective layer has been chosen after numerous high-temperature tests, where copper plates coated with different kinds of coatings were evaluated. What is more, we present results of the high-temperature reliability tests of copper coated fibers protected with our multilayer coating. Performed tests proved that our solution significantly improved optical fibers' reliability to both: elevated temperatures and rapid changes of temperature. Furthermore the developed metal coatings allow fibers' to be electrolytically bonded to other metal elements (e.g. sensor transducers) what makes them great candidates for harsh environment fiber optic sensor applications.

  1. Advanced optical coatings for astronomical instrumentation

    NASA Astrophysics Data System (ADS)

    Pradal, Fabien; Leplan, Hervé; Vayssade, Hervé; Geyl, Roland

    2016-07-01

    Recently Safran Reosc worked and progressed on various thin film technology for: Large mirrors with low stress and stable coatings. Large lens elements with strong curvature and precise layer specifications. Large filters with high spectral response uniformity specifications. IR coatings with low stress and excellent resistance to cryogenic environment for NIR to LWIR domains. Pixelated coatings. Results will be presented and discussed on the basis of several examples.

  2. Optical interference coating design contest 2016: a dispersive mirror and coating uniformity challenge.

    PubMed

    Kruschwitz, Jennifer D T; Pervak, Vladimir; Keck, Jason; Bolshakov, Ilya; Gerig, Zachary; Lemarchand, Fabien; Sato, Kageyuki; Southwell, William; Sugiura, Muneo; Trubetskov, Michael; Yuan, Wenjia

    2017-02-01

    A dispersive mirror and a coating uniformity challenge were the topics of the design contest held in conjunction with the 2016 Optical Interference Coatings topical meeting of The Optical Society (OSA). A total of 18 designers from China, France, Germany, Japan, and the United States submitted 38 total designs for problems A and B. Michael Trubetskov submitted the winning designs for all four design challenges. The design problems and the submitted solutions are described and evaluated.

  3. Optical Diagnostics of Thermal Barrier Coatings

    NASA Astrophysics Data System (ADS)

    Majewski, Mark Steven

    The high temperature properties of ceramic materials make them suitable for the extreme environments of gas combustion powered turbines. They are instrumental in providing thermal insulation for the metallic turbine components from the combustion products. Also, the addition of specific rare earth elements to ceramics creates materials with temperature diagnostic applications. Laser based methods have been applied to these ceramic coatings to predict their remaining thermal insulation service life and to explore their high temperature diagnostic capabilities. A method for cleaning thermal barrier coatings (TBCs) contaminated during engine operation has been developed using laser ablation. Surface contamination on the turbine blades hinders nondestructive remaining life prediction using photo luminescence piezospectroscopy (PLPS). Real time monitoring of the removed material is employed to prevent damage to the underlying coating. This method relies on laser induced breakdown spectroscopy (LIBS) to compute the cross correlation coefficient between the spectral emissions of a sample TBC that is contaminated and a reference clean TBC. It is possible to remove targeted contaminants and cease ablation when the top surface of the TBC has been reached. In collaboration with this work, Kelley's thesis [1] presents microscopy images and PLPS measurements indicating the integrity of the TBC has been maintained during the removal of surface contaminants. Thermographic phosphors (TGP) have optical emission properties when excited by a laser that are temperature dependent. These spectral and temporal properties have been investigated and utilized for temperature measurement schemes by many previous researchers. The compounds presented in this dissertation consist of various rare earth (Lanthanide) elements doped into a host crystal lattice. As the temperature of the lattice changes, both the time scale for vibrational quenching and the distribution of energy among atomic energy

  4. Microbubble generation using fiber optic tips coated with nanoparticles.

    PubMed

    Pimentel-Domínguez, Reinher; Hernández-Cordero, Juan; Zenit, Roberto

    2012-04-09

    We show that fiber optic tips can be used as microbubble generators in liquid media. Using standard single-mode silica fibers incorporating nanoparticles (carbon nanoparticles and metallic powders), bubbles can be generated with low optical powers owing to the enhanced photothermal effects of the coating materials. We provide details about the hydrodynamic effects generated in the vicinity of the fiber tip during the coating process, bubble generation and growth. Flow visualization techniques show that thermal effects lead to bubble formation on the tip of the fibers, and coating optimization is crucial for optimal performance of the probes.

  5. Electron Emission Observations from As-Grown and Vacuum-Coated Chemical Vapor Deposited Diamond

    NASA Technical Reports Server (NTRS)

    Lamouri, A.; Wang, Yaxin; Mearini, G. T.; Krainsky, I. L.; Dayton, J. A., Jr.; Mueller,W.

    1996-01-01

    Field emission has been observed from chemical vapor deposited diamond grown on Mo and Si substrates. Emission was observed at fields as low as 20 kV/cm. The samples were tested in the as-grown form, and after coating with thin films of Au, CsI, and Ni. The emission current was typically maximum at the onset of the applied field, but was unstable, and decreased rapidly with time from the as-grown films. Thin Au layers, approximately 15 nm thick, vacuum deposited onto the diamond samples significantly improved the stability of the emission current at values approximately equal to those from uncoated samples at the onset of the applied field. Thin layers of CsI, approximately 5 nm thick, were also observed to improve the stability of the emission current but at values less than those from the uncoated samples at the onset of the applied field. While Au and CsI improved the stability of the emission, Ni was observed to have no effect.

  6. Vacuum-deposited optical coatings experiment (A0138-4)

    NASA Technical Reports Server (NTRS)

    Malherbe, A.

    1984-01-01

    The stability of various vacuum deposited optical coatings exposed to the space environment were analyzed. A wide range of optical components manufactured by vacuum deposition, such as metallic and multidielectric reflective coatings in the UV range, metal dielectric interference filtes in the UV and IR ranges, narrow-bandpass filters int he near-UV and visible ranges, selective metallic mirrors in the range from 1500 to 2500 A. antireflective and reflective IR coatings, beam splitters in the visible and IR ranges, and optical surface reflection (OSR) coatings were developed. Many of these components were incorporated into scientific and technical experiments flown on balloons and rockets as well as on Symphonie, Meteosate, OTS, D2-B, TIROS n, and others. It appears that these components operate successfully in flight.

  7. Optical enhancing durable anti-reflective coating

    DOEpatents

    Maghsoodi, Sina; Varadarajan, Aravamuthan; Movassat, Meisam

    2016-07-05

    Disclosed herein are polysilsesquioxane based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In embodiments, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in the polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, Si--OH condensation catalyst and/or nanofillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes including flow coating and roll coating, and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  8. Optically transparent, scratch-resistant, diamond-like carbon coatings

    DOEpatents

    He, Xiao-Ming; Lee, Deok-Hyung; Nastasi, Michael A.; Walter, Kevin C.; Tuszewski, Michel G.

    2003-06-03

    A plasma-based method for the deposition of diamond-like carbon (DLC) coatings is described. The process uses a radio-frequency inductively coupled discharge to generate a plasma at relatively low gas pressures. The deposition process is environmentally friendly and scaleable to large areas, and components that have geometrically complicated surfaces can be processed. The method has been used to deposit adherent 100-400 nm thick DLC coatings on metals, glass, and polymers. These coatings are between three and four times harder than steel and are therefore scratch resistant, and transparent to visible light. Boron and silicon doping of the DLC coatings have produced coatings having improved optical properties and lower coating stress levels, but with slightly lower hardness.

  9. In situ optical characterization and reengineering of interference coatings.

    PubMed

    Wilbrandt, Steffen; Stenzel, Olaf; Kaiser, Norbert; Trubetskov, Michael K; Tikhonravov, Alexander V

    2008-05-01

    A new optical monitoring system has been developed that allows recording of transmission spectra in the wavelength range between 400 and 920 nm of a growing optical coating during deposition. Several kinds of thin film sample have been prepared by use of a hybrid monitoring strategy that is essentially based on a combination of quartz monitoring and in situ transmission spectra measurements. We demonstrate and discuss the applicability of our system for reengineering procedures of high-low stacks and measurements of small vacuum or thermal shifts of optical coatings.

  10. Coating Procedure of Subaru Telescope Optics

    NASA Astrophysics Data System (ADS)

    Hayashi, Saeko S.; Kamata, Yukiko; Kanzawa, Tomio; Miyashiti, Akihiko; Nakagiri, Masao; Nishimura, Tetsuo; Noguchi, Takeshi; Okita, Kiichi; Oshima, Norio; Sasaki, Goro; Torii, Yasuo; Yutani, Masami; Ishikawa, Tsuyoshi

    For coating large mirrors of Subaru Telescope, we employ conventional evaporation scheme because it is known for uniform coverage. We will report installation and the performance verification of the coating facility of Subaru telescope. The coating facility consists of a washing tower for stripping the old coating from the primary mirror, a large evaporation coating chamber, two trolleys for the primary mirror, and a scissors-like primary mirror lifter. Tests with large coating chamber at Mauna Kea, as well as with smaller chamber at Mitaka, will be discussed. To supply a large number of filaments with uniform quality, our practical solution is to pre-wet the filaments and keep them in a controlled environment before the evaporation. In the initial test, aluminum film over the large area exceeded the number targeted for the thickness and yet the uniformity turned out to be better than the specification. Reflectivity of the fresh surface was over 90% at visible wavelength. In September 1997, we re-aluminized 1.6m infrared simulator at Mitaka for the first time using pre-wetted filaments. The result verified our coating procedures for the secondary mirror in late 1997 and the 8.3m primary mirror in early in 1998.

  11. Laser Damage in Thin Film Optical Coatings

    DTIC Science & Technology

    1992-07-01

    OTHER RELEVANT ISSUES The damage thresholds of refractory oxides used as AR coatings for alexandrite laser rods were determined and measured by...used and a limited number of TiO 2/SiO2 coatings were put on alexandrite substrates. Single layer AR coatings of MgF2 and NaAIF 6 were also tested for...measurements were made using an alexandrite laser at a wavelength of 790 nm. with a pulse duration of 200 nsec at 30Hz for 2 seconds. The near spot

  12. Space environmental effects on coated optics

    NASA Technical Reports Server (NTRS)

    Donovan, T. M.; Bennett, J. M.; Gyetvay, S. R.

    1991-01-01

    Several multilayer coated mirror designs developed for potential space applications were tested on the Long Duration Exposure Facility (LDEF) along with single layer witness coatings deposited on fused silica and a coated CaF2 window. Performance requirements included high mirror reflectivity, low absorption, low scatter, environmental durability, and radiation hardness. The designs were selected in screening tests using combined electron, proton, and simulated solar UV radiation. The purpose of the space test was to validate the above test results and determine the effects of atomic oxygen and contamination on mirror performance.

  13. Optically transparent, superhydrophobic methyltrimethoxysilane based silica coatings without silylating reagent

    NASA Astrophysics Data System (ADS)

    Kavale, Mahendra S.; Mahadik, D. B.; Parale, V. G.; Wagh, P. B.; Gupta, Satish C.; Rao, A. Venkateswara; Barshilia, Harish C.

    2011-10-01

    The superhydrophobic surfaces have drawn lot of interest, in both academic and industries because of optically transparent, adherent and self-cleaning behavior. Surface chemical composition and morphology plays an important role in determining the superhydrophobic nature of coating surface. Such concert of non-wettability can be achieved, using surface modifying reagents or co-precursor method in sol-gel process. Attempts have been made to increase the hydrophobicity and optical transparency of methyltrimethoxysilane (MTMS) based silica coatings using polymethylmethacrylate (PMMA) instead of formal routes like surface modification using silylating reagents. The optically transparent, superhydrophobic uniform coatings were obtained by simple dip coating method. The molar ratio of MTMS:MeOH:H 2O was kept constant at 1:5.63:1.58, respectively with 0.5 M NH 4F as a catalyst and the weight percent of PMMA varied from 1 to 8. The hydrophobicity of silica coatings was analyzed by FTIR and contact angle measurements. These substrates exhibited 91% optical transmittance as compared to glass and water drop contact angle as high as 171 ± 1°. The effect of humidity on hydrophobic nature of coating has been studied by exposing these films at relative humidity of 90% at constant temperature of 30 °C for a period of 45 days. The micro-structural studies carried out by transmission electron microscopy (TEM).

  14. Anti-biofouling coatings for optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Mignani, Anna G.; Bizzarri, P.; Driver, M.; Palmer, R.; Liefeith, K.; Hildebrand, G.; Dakin, John P.

    2002-02-01

    One of the most serious problems relevant to the use of optical fiber sensors in real-world environments is surface fouling, that is, the cumulative build-up of undesirable material on the working surface of a sensor. This paper present the results of anti-biofouling tests on coated fiber optic probes for reflectance spectroscopy in blood- simulating foul media, namely Bovine Serum Albumin (BSA) and Fibrinogen. The anti-biofouling coating, a proprietary invention of Biocompatibles Ltd., was a cross-linkable Phosphorylcholine (PC) polymer with Silane functionality, to improve adhesion to silica-containing substrates. All tests in BSA and Fibrinogen showed that PC-1036 coating was efficient in avoiding the build-up of biological material. In fact, optical signal variations of un-coated probes showed fluctuations in the 6-20% range, while coated probes exhibited a nearly-stable optical signal. These results were also confirmed by a microscopic check, which showed adhesions of biological material to un-coated probes.

  15. Moisture-resistant coatings for optical components

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.; Johnson, C. C.

    1973-01-01

    Plasma polymerization technique is used to apply thin, adherent, hydrophobic coatings from chlorotrifluoroethylene monomer. Apparently much of the chlorine contained in original monomer is lost during polymerization, and characteristic C-Cl absorption in infrared region is essentially absent.

  16. Plasmon enhanced optical tweezers with gold-coated black silicon

    PubMed Central

    Kotsifaki, D. G.; Kandyla, M.; Lagoudakis, P. G.

    2016-01-01

    Plasmonic optical tweezers are a ubiquitous tool for the precise manipulation of nanoparticles and biomolecules at low photon flux, while femtosecond-laser optical tweezers can probe the nonlinear optical properties of the trapped species with applications in biological diagnostics. In order to adopt plasmonic optical tweezers in real-world applications, it is essential to develop large-scale fabrication processes without compromising the trapping efficiency. Here, we develop a novel platform for continuous wave (CW) and femtosecond plasmonic optical tweezers, based on gold-coated black silicon. In contrast with traditional lithographic methods, the fabrication method relies on simple, single-step, maskless tabletop laser processing of silicon in water that facilitates scalability. Gold-coated black silicon supports repeatable trapping efficiencies comparable to the highest ones reported to date. From a more fundamental aspect, a plasmon-mediated efficiency enhancement is a resonant effect, and therefore, dependent on the wavelength of the trapping beam. Surprisingly, a wavelength characterization of plasmon-enhanced trapping efficiencies has evaded the literature. Here, we exploit the repeatability of the recorded trapping efficiency, offered by the gold-coated black silicon platform, and perform a wavelength-dependent characterization of the trapping process, revealing the resonant character of the trapping efficiency maxima. Gold-coated black silicon is a promising platform for large-scale parallel trapping applications that will broaden the range of optical manipulation in nanoengineering, biology, and the study of collective biophotonic effects. PMID:27195446

  17. Plasmon enhanced optical tweezers with gold-coated black silicon

    NASA Astrophysics Data System (ADS)

    Kotsifaki, D. G.; Kandyla, M.; Lagoudakis, P. G.

    2016-05-01

    Plasmonic optical tweezers are a ubiquitous tool for the precise manipulation of nanoparticles and biomolecules at low photon flux, while femtosecond-laser optical tweezers can probe the nonlinear optical properties of the trapped species with applications in biological diagnostics. In order to adopt plasmonic optical tweezers in real-world applications, it is essential to develop large-scale fabrication processes without compromising the trapping efficiency. Here, we develop a novel platform for continuous wave (CW) and femtosecond plasmonic optical tweezers, based on gold-coated black silicon. In contrast with traditional lithographic methods, the fabrication method relies on simple, single-step, maskless tabletop laser processing of silicon in water that facilitates scalability. Gold-coated black silicon supports repeatable trapping efficiencies comparable to the highest ones reported to date. From a more fundamental aspect, a plasmon-mediated efficiency enhancement is a resonant effect, and therefore, dependent on the wavelength of the trapping beam. Surprisingly, a wavelength characterization of plasmon-enhanced trapping efficiencies has evaded the literature. Here, we exploit the repeatability of the recorded trapping efficiency, offered by the gold-coated black silicon platform, and perform a wavelength-dependent characterization of the trapping process, revealing the resonant character of the trapping efficiency maxima. Gold-coated black silicon is a promising platform for large-scale parallel trapping applications that will broaden the range of optical manipulation in nanoengineering, biology, and the study of collective biophotonic effects.

  18. Plasmon enhanced optical tweezers with gold-coated black silicon.

    PubMed

    Kotsifaki, D G; Kandyla, M; Lagoudakis, P G

    2016-05-19

    Plasmonic optical tweezers are a ubiquitous tool for the precise manipulation of nanoparticles and biomolecules at low photon flux, while femtosecond-laser optical tweezers can probe the nonlinear optical properties of the trapped species with applications in biological diagnostics. In order to adopt plasmonic optical tweezers in real-world applications, it is essential to develop large-scale fabrication processes without compromising the trapping efficiency. Here, we develop a novel platform for continuous wave (CW) and femtosecond plasmonic optical tweezers, based on gold-coated black silicon. In contrast with traditional lithographic methods, the fabrication method relies on simple, single-step, maskless tabletop laser processing of silicon in water that facilitates scalability. Gold-coated black silicon supports repeatable trapping efficiencies comparable to the highest ones reported to date. From a more fundamental aspect, a plasmon-mediated efficiency enhancement is a resonant effect, and therefore, dependent on the wavelength of the trapping beam. Surprisingly, a wavelength characterization of plasmon-enhanced trapping efficiencies has evaded the literature. Here, we exploit the repeatability of the recorded trapping efficiency, offered by the gold-coated black silicon platform, and perform a wavelength-dependent characterization of the trapping process, revealing the resonant character of the trapping efficiency maxima. Gold-coated black silicon is a promising platform for large-scale parallel trapping applications that will broaden the range of optical manipulation in nanoengineering, biology, and the study of collective biophotonic effects.

  19. Highly enhanced and temporally stable field emission from MWCNTs grown on aluminum coated silicon substrate

    SciTech Connect

    Sreekanth, M.; Ghosh, S. Patra, R.; Srivastava, P.

    2015-06-15

    In this work, a detailed field emission study of multi-walled carbon nanotubes (MWCNTs) grown on Si and Al coated Si substrates is reported. Morphological and microstructural studies of the films show higher entanglement of CNTs in the case of CNT/Si film as compared to CNT/Al/Si film. Raman studies show that the defect mediated peak (D) is substantially suppressed as compared to graphitic peak (G) resulting in significant reduction in I{sub D}/I{sub G} value in CNT/Al/Si film. Field emission (FE) current density of CNT/Al/Si film (∼25 mA/cm{sup 2}) is significantly higher as compared to that of CNT/Si film (∼1.6 mA/cm{sup 2}). A substantial improvement in temporal stability is also observed in CNT/Al/Si film. This enhancement in field emission current is attributed to strong adhesion between substrate and CNTs, low work function, high local field enhancement factor at the CNT tips and less entanglement of CNTs grown on Al/Si. The temporally stable CNT/Al/Si cold cathode can be a potential candidate to replace conventional electron sources in prototype devices.

  20. Sol-gel optical coatings for lasers, 3

    SciTech Connect

    Floch, H.G.; Belleville, P.F.; Priotton, J.J.; Pegon, P.M.; Dijonneau, C.S.; Guerain, J.

    1995-12-01

    The planned megajoule-class neodymium-glass laser system will be the world`s largest. The proposed CEL-V design, based on the use of 240 beams, will use 50--150 times more optical material than did Phebus. Almost 10,000 m{sup 2} of coated area are required for optical coatings; this is a factor of almost 500 increase over Phebus. Lens, flashlamp, blastshield, harmonic converter, debris shield, window and cavity-end mirror coatings by the sol-gel process represent >96% of the entire coated area. The remaining <4% are high-rejection-ratio polarizers, pick-off cavity mirrors and transport mirrors. Cost estimates show that, for coating deposition, the sol-gel technique provides considerable saving compared to the more conventional e-beam deposition technique. Highly reflective and polarizing sol-gel-derived optical coatings have been prepared and tested for the proposed French megajoule neodymium-glass laser. Laser damage studies are reported here.

  1. Inhomogeneous optical coatings: an experimental study of a new approach.

    PubMed

    Bertram, R; Ouellette, M F; Tse, P Y

    1989-07-15

    Inhomogeneous optical interference coatings offer a potentially superior alternative to their multilayer counterparts in meeting rigid performance requirements. However, their development has been severely hampered by the lack of appropriate design software and process control hardware. The work reported in this paper involved the experimental design and fabrication of a number of inhomogeneous coatings, and some interesting results were obtained. Using customized algorithms and simultaneous codeposition techniques, an inhomogeneous antireflection coating based on germanium and thorium fluoride has been successfully produced. Attempts with other materials such as zinc sulfide were less successful because of discrepancies between predicted and actual deposition rates, and further studies are being conducted.

  2. Knowledge-based optical coatings design and manufacturing

    NASA Astrophysics Data System (ADS)

    Guenther, Karl H.; Gonzalez, Avelino J.; Yoo, Hoi J.

    1990-12-01

    The theory of thin film optics is well developed for the spectral analysis of a given optical coating. The inverse synthesis - designing an optical coating for a certain spectral performance - is more complicated. Usually a multitude of theoretical designs is feasible because most design problems are over-determined with the number of layers possible with three variables each (n, k, t). The expertise of a good thin film designer comes in at this point with a mostly intuitive selection of certain designs based on previous experience and current manufacturing capabilities. Manufacturing a designed coating poses yet another subset of multiple solutions, as thin if in deposition technology has evolved over the years with a vast variety of different processes. The abundance of published literature may often be more confusing than helpful to the practicing thin film engineer, even if he has time and opportunity to read it. The choice of the right process is also severely limited by the given manufacturing hardware and cost considerations which may not easily allow for the adaption of a new manufacturing approach, even if it promises to be better technically (it ought to be also cheaper). On the user end of the thin film coating business, the typical optical designer or engineer who needs an optical coating may have limited or no knowledge at all about the theoretical and manufacturing criteria for the optimum selection of what he needs. This can be sensed frequently by overly tight tolerances and requirements for optical performance which sometimes stretch the limits of mother nature. We introduce here a know1edge-based system (KBS) intended to assist expert designers and manufacturers in their task of maximizing results and minimizing errors, trial runs, and unproductive time. It will help the experts to manipulate parameters which are largely determined through heuristic reasoning by employing artificial intelligence techniques. In a later state, the KBS will include a

  3. Optical coatings for artworks preservation and enhanced viewing

    NASA Astrophysics Data System (ADS)

    Piegari, A.; Arrighi, R.; Di Sarcina, I.; Farini, A.

    2005-09-01

    Many optical methods are nowadays in use in the field of art. Most techniques are applied for characterization of materials, monitoring, diagnostics. Optical thin films can find an interesting application for artwork protection from the damage induced by illumination. The deteriorating effect of light on artworks is well known and the conventional approach to reduce the damage consists in lowering the radiation intensity and shortening the exposure duration. A complementary approach is to block all radiations that are not useful for viewing the artwork. A proper optical coating deposited on glass is able to cut the radiation flux at all wavelengths outside the range of sensitivity of the human eye. Glass is already in use in museum and galleries to protect artwork from vandalism and the use of coated glass can result in a simple method for contributing to art conservation. The optical coating will also improve the viewing because of the antireflection effect that can be combined with the protection properties. Particular care must be taken of this aspect because a compromise between conservation rules and visitor satisfaction must be reached. It is important that the thin-film coating does not introduce color alterations from the point of view of the observer and for this reason color testing on coated glasses must be carried out with real viewers.

  4. Effects of container cavity size and copper coating on field performance of container-grown longleaf pine seedlings

    Treesearch

    Shi-Jean Susana Sung; James D. Haywood; Mary A. Sword-Sayer; Kristina F. Connor; D. Andrew Scott

    2010-01-01

    Longleaf pine (Pinus palustris Mill.) seedlings were grown for 27 weeks in 3 container cavity sizes [small (S), medium (M), and large (L)], and half the containers were coated with copper (Cu). In November 2004, we planted 144 seedlings from each of 6 container treatments in each of 4 replications in central LA. All plots were burned in February 2006...

  5. Analysis of Coating Thickness Variation During Optical Fiber Processing

    NASA Astrophysics Data System (ADS)

    Jiang, Qibo; Yang, Fuzheng; Pitchumani, Ranga

    2005-03-01

    During the mass production of silica-based optical fibers, a large fiber preform is softened in a high-temperature furnace and is drawn to a small fiber with a diameter of about 125 μm . The hot fiber exiting the furnace is cooled rapidly by the surrounding air or by blowing a gas, and is subsequently coated with a polymer layer to provide a protection of the fiber surface. The overall quality of the fiber depends on the uniformity of the coating layer, which is strongly influenced by the manufacturing conditions. While the average thickness of the coating layer is extensively investigated in the literature, the studies on the coating thickness fluctuation lack a sound fundamental basis. In this paper, a linear perturbation analysis is adopted to predict the coating thickness variation under different processing conditions. An experimental correlation is developed to determine the initial amplitude of the thickness disturbance. Numerical results are presented for the first time to directly link the processing and geometric parameters with the coating thickness fluctuation in the final product. The results provide guidelines for selecting coating materials, system designs, and processing parameters to achieve uniform fiber coating layers.

  6. Improved Method for Laser Damage Testing Coated Optics

    SciTech Connect

    Borden, M R; Folta, J A; Stolz, C J; Taylor, J R; Wolfe, J E; Griffin, A J; Thomas, M D

    2005-10-25

    The damage test procedure for qualifying a coating run of anti-reflection coated optics consists of scanning a pulsed 1064 nm laser over a 1 cm x 1 cm area on a test sample to illuminate approximately 2400 sites. Scans are repeated at 3 J/cm{sup 2} increments until the fluence specification for the optic is reached. In the past, initiation of 1 or more damage sites was classified as a failed coating run, requiring the production optics in the corresponding coating lot be reworked and recoated. Recent laser damage growth tests of 300 repetitive pulses performed on numerous damage sites revealed that all were stable up to 20 J/cm{sup 2}. Therefore the acceptance criteria has been modified to allow a moderate number of damage sites, as long as they are smaller than the allowed dig size and are stable (do not grow). Consequently many coating runs that previously would have been rejected are now accepted, resulting in higher yield, lower cost, and improved delivery schedule. The new test also provides assurance that initiated damage sites are stable during long term operation.

  7. Optical properties of dielectric plates coated with gapped graphene

    NASA Astrophysics Data System (ADS)

    Klimchitskaya, G. L.; Mostepanenko, V. M.

    2017-01-01

    The optical properties of dielectric plates coated with gapped graphene are investigated on the basis of first principles of quantum electrodynamics. The reflection coefficients and reflectivities of graphene-coated plates are expressed in terms of the polarization tensor of gapped graphene and the dielectric permittivity of plate material. Simple approximate expressions for the required combinations of components of the polarization tensor applicable in the wide frequency region, where the presence of a gap influences the optical properties, are found. Numerical computations of the reflectivities of graphene-coated SiO 2 plates are performed for different values of the mass-gap parameter at different temperatures. It is shown that with an increasing gap width the reflectivity of a graphene-coated plate at the normal incidence decreases by up to a factor of 8 depending on the values of frequency and mass-gap parameter. The angle dependences of reflectivities for both polarizations of the incident electromagnetic waves have been computed for Si and SiO 2 plates coated with gapped graphene. We demonstrate that the TM reflectivity has a minimum value at some angle of incidence depending on the mass-gap parameter, frequency and temperature, whereas the TE reflectivity depends on the angle of incidence monotonously. However, for the graphene coatings with a nonzero mass-gap parameter the reflected light cannot be fully polarized. Possible applications of the obtained results are discussed.

  8. Coating Thin Mirror Segments for Lightweight X-ray Optics

    NASA Technical Reports Server (NTRS)

    Chan, Kai-Wing; Sharpe, Marton V.; Zhang, William; Kolosc, Linette; Hong, Melinda; McClelland, Ryan; Hohl, Bruce R.; Saha, Timo; Mazzarellam, James

    2013-01-01

    Next generations lightweight, high resolution, high throughput optics for x-ray astronomy requires integration of very thin mirror segments into a lightweight telescope housing without distortion. Thin glass substrates with linear dimension of 200 mm and thickness as small as 0.4 mm can now be fabricated to a precision of a few arc-seconds for grazing incidence optics. Subsequent implementation requires a distortion-free deposition of metals such as iridium or platinum. These depositions, however, generally have high coating stresses that cause mirror distortion. In this paper, we discuss the coating stress on these thin glass mirrors and the effort to eliminate their induced distortion. It is shown that balancing the coating distortion either by coating films with tensile and compressive stresses, or on both sides of the mirrors is not sufficient. Heating the mirror in a moderately high temperature turns out to relax the coated films reasonably well to a precision of about a second of arc and therefore provide a practical solution to the coating problem.

  9. Optical interference coatings 2007 measurement problem.

    PubMed

    Duparré, Angela; Ristau, Detlev

    2008-05-01

    The 2007 Measurement Problem comprised measurements of the transmission and reflectance spectra and the determination of optical constants for a single oxide layer on fused silica. The angle of incidence was 45 degrees .

  10. 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

  11. 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.

  12. Optical Property Evaluation of Next Generation Thermal Control Coatings

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Deshpande, Mukund S.; Pierson, Edward A.

    2010-01-01

    Next generation white thermal control coatings were developed via the Small Business Innovative Research program utilizing lithium silicate chemistry as a binder. Doping of the binder with additives yielded a powder that was plasma spray capable and that could be applied to light weight polymers and carbon-carbon composite surfaces. The plasma sprayed coating had acceptable beginning-of-life and end-of-live optical properties, as indicated by a successful 1.5 year exposure to the space environment in low Earth orbit. Recent studies also showed the coating to be durable to simulated space environments consisting of 1 keV and 10 keV electrons, 4.5 MeV electrons, and thermal cycling. Large scale deposition was demonstrated on a polymer matrix composite radiator panel, leading to the selection of the coating for use on the Gravity Recovery And Interior Laboratory (GRAIL) mission.

  13. Large area precision optical coatings by pulse magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Frach, Peter; Gloess, Daniel; Goschurny, Thomas; Drescher, Andy; Hartung, Ullrich; Bartzsch, Hagen; Heisig, Andreas; Grune, Harald; Leischnig, Lothar; Leischnig, Steffen; Bundesmann, Carsten

    2017-05-01

    Pulse magnetron sputtering is very well suited for the deposition of optical coatings. Due to energetic activation during film growth, sputtered films are dense, smooth and show an excellent environmental stability. Films of materials like SiO2, Al2O3, Nb2O5 or Ta2O5 can be produced with very little absorption and scattering losses and are well suited for precision optics. FEP's coating plant PreSensLine, a deposition machine dedicated for the development and deposition of precision optical layer systems will be presented. The coating machine (VON ARDENNE) is equipped with dual magnetron systems (type RM by FEP). Concepts regarding machine design, process technology and process control as well as in situ monitoring are presented to realize the high demands on uniformity, accuracy and reproducibility. Results of gradient and multilayer type precision optical coatings are presented. Application examples are edge filters and special antireflective coatings for the backlight of 3D displays with substrate size up to 300 x 400mm. The machine allows deposition of rugate type gradient layers by rotating a rotary table with substrates between two sources of the dual magnetron system. By combination of the precision drive (by LSA) for the substrate movement and a special pulse parameter variation during the deposition process (available with the pulse unit UBS-C2 of FEP), it is possible to adjust the deposition rate as a function of the substrate position exactly. The aim of a current development is a technology for the uniform coating of 3D-substrates and freeform components as well as laterally graded layers.

  14. Oleophobic optical coating deposited by magnetron PVD

    NASA Astrophysics Data System (ADS)

    Bernt, D.; Ponomarenko, V.; Pisarev, A.

    2016-09-01

    Thin oxinitride films of Zn-Sn-O-N and Si-Al-O-N were deposited on glass by reactive magnetron sputtering at various nitrogen-to-oxygen ratios. Nitrogen added to oxygen led to decrease of the surface roughness and increase of oleophobic properties studied by the oil-drop test. The best oleophobity was obtained for Zn-Sn-O-N oxinitride at Zn:Sn=1:1 and N:O=1:2. Improved oleophobic properties were also demonstrated if the oxinitride film was deposited on top of the multilayer coating as the final step in the industrial cycle of production of energy efficient glass.

  15. Optical Coatings 2-6 Microns.

    DTIC Science & Technology

    1978-03-01

    Coatings on CaF 2 and S rF 2 Substrates. 4. PbF 2 ( X / 2 ) on C a F 2 HF vapor , 30 Mi 167X 21 5. PbF 2 ( X / 4 ) on SrF 2 HF vapor , 305X 22 ThF 4 ( X...a) ( 110) Surface 30 M m . _ _ _ - b) (100) Surface 60 M m . F igu re 5. PbF 2 (X14) on S r F 2 . HF vapor , 305X 22

  16. Space environmental effects on coated optics

    NASA Technical Reports Server (NTRS)

    Donovan, T. M.; Bennett, J. M.; Dalbey, R. Z.; Burge, D. K.; Gyetvay, S.

    1992-01-01

    Several high reflectance mirrors and an output window were selected for the Long Duration Exposure Facility (LDEF) by pre-flight screening using laboratory simulation of natural space radiation. One mirror, a silicon/aluminum oxide design, showed expected excellent stability in orbit and a long shelf life. An aluminum oxide coated calcium fluoride window also showed good stability. Less stable but more interesting behavior was observed in the zinc sulfide based mirrors that showed contamination effects and related dendrite formation. These samples, which were located on both leading and trailing edges, also had interesting impact sites.

  17. 2004 Optical Society Of America's Topical Meeting on Optical Interference Coatings: Manufacturing Problem.

    PubMed

    Dobrowolski, J A; Browning, Stephen; Jacobson, Michael R; Nadal, Maria

    2006-03-01

    Results are presented for the second Optical Society of America's Optical Interference Coatings Manufacturing Problem. The participants were asked to produce multilayer coatings which, in the 450-650 nm spectral region and for light incident at 60 degrees, would have transmittances of 0.7 and 0.3 for p- and s-polarized light, respectively. Three different teams each submitted four solutions. Three different deposition processes were used to produce these coatings. The smallest average departure from the target transmission values was 0.79%. A number of interesting conclusions can be drawn from this exercise.

  18. Extraordinary optical transmission through metal-coated colloidal monolayers

    NASA Astrophysics Data System (ADS)

    Landström, L.; Brodoceanu, D.; Piglmayer, K.; Bäuerle, D.

    2006-09-01

    Extraordinary optical transmission through metal-coated close-packed monolayers has been observed. The monolayers consist of silica (a-SiO2) or polystyrene microspheres that form two-dimensional close-packed lattices by self-assembly. Metal layers of Ag, Au and Ni with different thicknesses (larger than the skin depth) were evaporated onto such lattices by means of standard techniques. The optical transmission spectra investigated between 300 and 2500 nm show pronounced peaks that scale with the diameter and the optical properties of the composite slabs. The enhanced transmission observed is most likely mediated via plasmons.

  19. Optical tissue phantoms based on spin coating method

    NASA Astrophysics Data System (ADS)

    Park, Jihoon; Ha, Myungjin; Yu, Sung Kon; Radfar, Edalat; Jun, Eunkwon; Lee, Nara; Jung, Byungjo

    2015-03-01

    Fabrication of optical tissue phantom (OTP) simulating whole skin structure has been regarded as laborious and time consuming work. This study fabricated multilayer OTP optically and structurally simulating epidermis-dermis structure including blood vessel. Spin coating method was used to produce thin layer mimicking epidermal layer, then optimized for reference epoxy and silicone matrix. Adequacy of both materials in phantom fabrication was considered by comparison the fabrication results. In addition similarities between OTP and biological tissue in optical property and thickness was measured to evaluate this fabrication process.

  20. Quantitative Topographical Characterization of Thermally Sprayed Coatings by Optical Microscopy

    NASA Astrophysics Data System (ADS)

    Schwaller, P.; Züst, R.; Michler, J.

    2009-03-01

    Topography measurements and roughness calculations for different rough surfaces (Rugotest surface comparator and thermally sprayed coatings) are presented. The surfaces are measured with a novel quantitative topography measurement technique based on optical stereomicroscopy and a comparison is made with established scanning stylus and optical profilometers. The results show that for most cases the different methods yield similar results. Stereomicroscopy is therefore a valuable method for topographical investigations in both quality control and research. On the other hand, the method based on optical microscopy demands a careful optimization of the experimental settings like the magnification and the illumination to achieve satisfactory results.

  1. Composition for forming an optically transparent, superhydrophobic coating

    SciTech Connect

    Simpson, John T.; Lewis, Linda A.

    2015-12-29

    A composition for producing an optically clear, well bonded superhydrophobic coating includes a plurality of hydrophobic particles comprising an average particle size of about 200 nm or less, a binder at a binder concentration of from about 0.1 wt. % to about 0.5 wt. %, and a solvent. The hydrophobic particles may be present in the composition at a particle concentration of from about 0.1 wt. % to about 1 wt. %. An optically transparent, superhydrophobic surface includes a substrate, a plurality of hydrophobic particles having an average particle size of about 200 nm or less dispersed over the substrate, and a discontinuous binder layer bonding the hydrophobic particles to the substrate, where the hydrophobic particles and the binder layer form an optically transparent, superhydrophobic coating.

  2. Mechanical properties of polyimide coated optical fibers at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Huang, Lei; Dyer, Robert S.; Lago, Ralph J.; Stolov, Andrei A.; Li, Jie

    2016-03-01

    High temperature mechanical strength and reliability of optical fibers have become important subjects as optical fibers are increasingly used for harsher environments. Theories and models of fiber mechanical properties established for traditional telecommunications applications may need to be validated for applications at elevated temperatures. In this paper, we describe the test setup for high temperature tensile strength of fiber and report initial results of dynamic tensile strength of polyimide coated optical fiber at 300 and 350ºC for different heating time intervals. The results are compared with room temperature strength data, data available in the literature, and our earlier work on thermogravimetric analysis (TGA) weight loss of the polyimide coating and the observations on surface morphology at elevated temperatures. Interesting observations are discussed and possible explanations are proposed.

  3. Optical, Electrical, and UV Photoresponse Properties of Fluorine-Doped ZnO Thin Films Grown on Flexible Mica Substrates

    NASA Astrophysics Data System (ADS)

    Kim, Younggyu; Leem, Jae-Young

    2015-12-01

    Fluorine-doped ZnO (FZO) thin films have several potential applications, for instance, in low-cost optoelectronic devices; understanding how their optical, electrical, and photoresponse properties depend on and can be controlled via the synthesis conditions is essential for application of these systems. In this study, FZO thin films with different annealing temperatures were grown on muscovite mica substrates via sol-gel spin-coating. In photoluminescence measurements, a strong peak in the ultraviolet (UV) region and a broad peak in the visible region were observed for all films, being strongly dependent on the annealing temperature. The transmittance of the annealed films was slightly higher than that of as-grown film, and the absorption edges in the transmittance spectra red-shifted with increasing annealing temperature. The optical bandgap and Urbach energy of the films were calculated from the absorption coefficient values, using the Tauc and Urbach relations, respectively. Finally, the electrical (i.e., resistivity and carrier concentration) and photoresponse properties of the films were investigated to assess their applicability for use in FZO-based UV detectors.

  4. Optical properties of an optically rough coating from inversion of diffuse reflectance measurements

    NASA Astrophysics Data System (ADS)

    Murphy, Anthony B.

    2007-06-01

    A method is developed for determining the optical properties of an optically rough coating on an opaque substrate from reflectance measurements. A modified Kubelka-Munk two- flux model is used to calculate the reflectance of the coating as a function of the refractive index, absorption coefficient, scattering coefficient, and thickness. The calculated reflectance is then fitted to measurements using a spectral projected gradient algorithm, allowing the optical properties to be obtained. The technique is applied to titanium dioxide coatings on a titanium substrate. Realistic values of refractive index and absorption coefficients are generally obtained. Quantities that are useful for solar water-splitting applications are calculated, including the depth profile of absorption and the proportion of the incident photon flux absorbed in the coating under solar illumination.

  5. Ion Assisted Deposition of Optical Coatings.

    DTIC Science & Technology

    1986-08-01

    comparable to the value of 2.15 for e-team evaporated Ta205 reported by Herrmann. 49 Demiryont, Sites and Geib reported a value of 2.18 for ion-beam...243 (1982). 156 15. H. Demiryont, J. R. Sites and Kent Geib , "Effects of oxygen content on the optical properties of tantalum oxide films deposited by

  6. Vacuum deposited optical coatings experiment (AO 138-4)

    NASA Technical Reports Server (NTRS)

    Charlier, Jean

    1991-01-01

    The aim of this experiment was to test the optical behavior of 20 components and coatings subjected to space exposure. Most of them are commonly used for their reflective or transmittive properties in spaceborne optics. They consist in several kind of metallic and dielectric mirrors designed for the 0.12 to 10 microns spectrum, UV, and NIR bandpass filters, visible, and IR antireflecting coatings, visible/IR dichroic beam splitters, and visible beam splitter. The coatings were deposited on various substrates such as glasses, germanium, magnesium fluoride, quartz, zinc selenide, and kanigened aluminum. Several coating materials were used such as Al, Ag, Au, MgF2, LaF3, ThF3, ThF4, SiO2, TiO2, ZrO2, Al2O3, MgO, Ge, and ZnSe. Five samples of each component were manufactured. Two flight samples were mounted in such a way that one was directly exposed to space and the other looking backwards. The same arrangement was used for the spare samples stored on ground in a box identical to the flight one and they were kept under vacuum during the LDEF mission. Finally, one set of reference components was stocked in a sealed box under a dry nitrogen atmosphere. By comparing the preflight and postflight optical performances of the five samples of each component, it is possible to detect the degradations due to the space exposure.

  7. Vacuum deposited optical coatings experiment (AO 138-4)

    NASA Technical Reports Server (NTRS)

    Charlier, Jean

    1991-01-01

    The aim of this experiment was to test the optical behavior of 20 components and coatings subjected to space exposure. Most of them are commonly used for their reflective or transmittive properties in spaceborne optics. They consist in several kind of metallic and dielectric mirrors designed for the 0.12 to 10 microns spectrum, UV, and NIR bandpass filters, visible, and IR antireflecting coatings, visible/IR dichroic beam splitters, and visible beam splitter. The coatings were deposited on various substrates such as glasses, germanium, magnesium fluoride, quartz, zinc selenide, and kanigened aluminum. Several coating materials were used such as Al, Ag, Au, MgF2, LaF3, ThF3, ThF4, SiO2, TiO2, ZrO2, Al2O3, MgO, Ge, and ZnSe. Five samples of each component were manufactured. Two flight samples were mounted in such a way that one was directly exposed to space and the other looking backwards. The same arrangement was used for the spare samples stored on ground in a box identical to the flight one and they were kept under vacuum during the LDEF mission. Finally, one set of reference components was stocked in a sealed box under a dry nitrogen atmosphere. By comparing the preflight and postflight optical performances of the five samples of each component, it is possible to detect the degradations due to the space exposure.

  8. Performance-limiting factors in optical coatings

    NASA Astrophysics Data System (ADS)

    MacLeod, H. A.

    1981-01-01

    A qualitative analysis is given to the problem of the shortfalls of thin film performance below the theoretical potential. The ideal performance is described, that is, what designers could achieve if layers could be deposited with the ideal properties of homogeneous, parallel-sided slabs of bulk-like material. Losses as low as 1 dB/km are achievable in bulk materials, but are not a representative loss in thin films. Moisture and other contaminants can be adsorbed onto the thin film surface, and capillary action can cause all the void space in the film to fill with water. Moisture helps reduce durability by lowering the surface energy, and it increases the likelihood of adhesion failures. For high intensity coatings, the main cause of performance below ideal is long and short pulse laser damage.

  9. Side-detecting optical fiber coated with Zn(OH)2 nanorods for ultraviolet sensing applications

    NASA Astrophysics Data System (ADS)

    Azad, S.; Parvizi, R.; Sadeghi, E.

    2017-09-01

    This paper presents an improved coupling efficiency and side detecting of UV radiation induced by light scattering and luminescent features of Zn(OH)2 nanorods coated multimode optical fibers. Uniform and high density Zn(OH)2 nanorods were grown hydrothermally on the core of chemically etched multimode optical fibers. The prepared samples were characterized through x-ray diffraction patterns, scanning electron microscopy and photoluminescence spectroscopy. The detecting technique was based on the intensity modulation of the side coupled light through the Zn(OH)2 nanorods. A simple and cost-effective UV radiation detecting setup has been designed. Experimentally estimated coupling efficiency of the proposed setup was obtained near 11%. The proposed device exhibited stable and reversible responses with a fast rising and decaying time of about 1.4 s and 0.85 s, respectively.

  10. Optical coherence tomography for evaluation of enamel and protective coatings.

    PubMed

    Alsayed, Ehab Z; Hariri, Ilnaz; Sadr, Alireza; Nakashima, Syozi; Bakhsh, Turki A; Shimada, Yasushi; Sumi, Yasunori; Tagami, Junji

    2015-01-01

    Optical coherence tomography (OCT) is an interferometric imaging technique. This study aimed to employ OCT to evaluate four different resin-based materials including a coating containing glass-ionomer filler and calcium, a giomer, and two fluoride-releasing self-etch resins. The coating and its underlying and adjacent enamel were monitored using swept-source OCT (center wavelength: 1330 nm) at baseline, after 5,000 thermal cycles, and after 1, 4 and 7 days of demineralization (pH 4.5). The coatings showed different thicknesses (60-250 micrometers) and various levels of structural and interfacial integrity. OCT could detect a demineralization inhibition zone adjacent to the edge of the fluoride- and calcium-releasing material. Localized demineralization was occasionally observed under thinner coatings. Protection of susceptible enamel surfaces by thin resin-based bioactive coatings provides protection from demineralization. OCT can be used to non-destructively monitor the integrity of such coatings, as well as enamel changes beneath and adjacent to them.

  11. Nanocrystallized Cu2Se grown on electroless Cu coated p-type Si using electrochemical atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Lu; He, Wenya; Chen, Xiang-yu; Du, Yi; Zhang, Xin; Shen, Yehua; Yang, Fengchun

    2015-01-01

    Cuprous selenide (Cu2Se) nanocrystalline thin films are grown onto electroless Cu coating on p-Si (100) substrates using electrochemical atomic layer deposition (EC-ALD), which includes alternate electrodeposition of Cu and Se atomic layers. The obtained films were characterized by X-ray diffraction (XRD), field emission scanning electronic microscopy (FE-SEM), FTIR, and open-circuit potential (OCP) studies. The results show the higher quality and good photoelectric properties of the Cu2Se film, suggesting that the combination of electroless coating and EC-ALD is an ideal method for deposition of compound semiconductor films on p-Si.

  12. Optical Society of America's 2010 Topical Meeting on Optical Interference Coatings: introduction by the feature editors.

    PubMed

    Stolz, Christopher J; Tilsch, Markus K; Ristau, Detlev

    2011-03-20

    This Applied Optics feature issue is dedicated to the eleventh topical meeting on Optical Interference Coatings held on 6-11 June 2010 in Tucson, Arizona, USA. This topical conference is held in a three year rotation with conferences in Europe and Asia and is a premier opportunity to discuss advances in research and development within the field of optical interference coatings. Papers from this meeting cover a broad range of topics ranging from deposition processes, thin film design, materials, metrology, and a wide array of practical applications.

  13. The Optical Society's 2016 topical meeting on optical interference coatings: introduction.

    PubMed

    Ristau, Detlev; Li, Li; Sargent, Robert; Sytchkova, Anna

    2017-02-01

    This feature issue of Applied Optics is dedicated to the 13th Topical Meeting on Optical Interference Coatings, which was held June 19-24, 2016, in Tucson, Arizona, USA. The conference, taking place every three years, is a focal point for global technical interchange in the field of optical interference coatings and provides premier opportunities for people working in the field to present their new advances in research and development. Papers presented at the meeting covered a broad range of topics, including fundamental research on coating design theory, new materials, and deposition and characterization technologies, as well as the vast and growing number of applications in electronic displays, communication, optical instruments, high power and ultra-fast lasers, solar cells, space missions, gravitational wave detection, and many others.

  14. Linear and nonlinear optical properties of carbon nanotube-coated single-mode optical fiber gratings.

    PubMed

    Villanueva, Guillermo E; Jakubinek, Michael B; Simard, Benoit; Oton, Claudio J; Matres, Joaquín; Shao, Li-Yang; Pérez-Millán, Pere; Albert, Jacques

    2011-06-01

    Single-wall carbon nanotube deposition on the cladding of optical fibers has been carried out to fabricate an all-fiber nonlinear device. Two different nanotube deposition techniques were studied. The first consisted of repeatedly immersing the optical fiber into a nanotube supension, increasing the thickness of the coating in each step. The second deposition involved wrapping a thin film of nanotubes around the optical fiber. For both cases, interaction of transmitted light through the fiber core with the external coating was assisted by the cladding mode resonances of a tilted fiber Bragg grating. Ultrafast nonlinear effects of the nanotube-coated fiber were measured by means of a pump-probe pulses experiment. © 2011 Optical Society of America

  15. Characterization of 1064nm nanosecond laser-induced damage on antireflection coatings grown by atomic layer deposition.

    PubMed

    Liu, Zhichao; Chen, Songlin; Ma, Ping; Wei, Yaowei; Zheng, Yi; Pan, Feng; Liu, Hao; Tang, Gengyu

    2012-01-16

    Damage tests are carried out at 1064nm to measure the laser resistance of TiO(2)/Al(2)O(3) and HfO(2)/Al(2)O(3) antireflection coatings grown by atomic layer deposition (ALD). The damage results are determined by S-on-1 and R-on-1 tests. Interestingly, the damage performance of ALD coatings is similar to those grown by conventional e-beam evaporation process. A decline law of damage resistance under multiple irradiations is revealed. The influence of growth temperature on damage performance has been investigated. Result shows that the crystallization of TiO(2) layer at higher temperature could lead to numerous absorption defects that reduce the laser-induced damage threshold (LIDT). In addition, it has been found that using inorganic compound instead of organic compound as precursors for ALD process maybe effectively prevent carbon impurities in films and will increase the LIDT obviously.

  16. Absorptance Measurements of Optical Coatings - A Round Robin

    SciTech Connect

    Chow, R; Taylor, J R; Wu, Z L; Boccara, C A; Broulik, U; Commandre, M; DiJon, J; Fleig, C; Giesen, A; Fan, Z X; Kuo, P K; Lalezari, R; Moncur, K; Obramski, H-J; Reicher, D; Ristau, D; Roche, P; Steiger, B; Thomsen, M; von Gunten, M

    2000-10-26

    An international round robin study was conducted on the absorption measurement of laser-quality coatings. Sets of optically coated samples were made by a ''reactive DC magnetron'' sputtering and an ion beam sputtering deposition process. The sample set included a high reflector at 514 nm and a high reflector for the near infrared (1030 to 1318 nm), single layers of silicon dioxide, tantalum pentoxide, and hafnium dioxide. For calibration purposes, a sample metalized with hafnium and an uncoated, superpolished fused silica substrate were also included. The set was sent to laboratory groups for absorptance measurement of these coatings. Whenever possible, each group was to measure a common, central area and another area specifically assigned to the respective group. Specific test protocols were also suggested in regards to the laser exposure time, power density, and surface preparation.

  17. Thermal noise from optical coatings in gravitational wave detectors.

    PubMed

    Harry, Gregory M; Armandula, Helena; Black, Eric; Crooks, D R M; Cagnoli, Gianpietro; Hough, Jim; Murray, Peter; Reid, Stuart; Rowan, Sheila; Sneddon, Peter; Fejer, Martin M; Route, Roger; Penn, Steven D

    2006-03-01

    Gravitational waves are a prediction of Einstein's general theory of relativity. These waves are created by massive objects, like neutron stars or black holes, oscillating at speeds appreciable to the speed of light. The detectable effect on the Earth of these waves is extremely small, however, creating strains of the order of 10(-21). There are a number of basic physics experiments around the world designed to detect these waves by using interferometers with very long arms, up to 4 km in length. The next-generation interferometers are currently being designed, and the thermal noise in the mirrors will set the sensitivity over much of the usable bandwidth. Thermal noise arising from mechanical loss in the optical coatings put on the mirrors will be a significant source of noise. Achieving higher sensitivity through lower mechanical loss coatings, while preserving the crucial optical and thermal properties, is an area of active research right now.

  18. Damage precursor measurements on UV-optical coatings

    SciTech Connect

    Ettrich, K.; Blaschke, H.; Welsch, E.

    1995-12-31

    For application in UV thin film optics the thermal contribution to the laser-induced optical breakdown was investigated utilizing time-resolved photothermal probe beam deflection (MIRAGE) technique. The potentiality of this method for the determination of both the subdamage range and the onset of single-shot-damage of Al{sub 2}O{sub 3}/SiO{sub 2} and LaF{sub 3}/MgF{sub 2} high-reflective coatings by using the thermal branch of the MIRAGE technique could be demonstrated. Examining the dielectric mirrors by 248 nm KrF laser irradiation, distinct damage precursor features were found. Thus, the physical origin of the UV pulsed radiation breakdown in HR coatings can be elucidated.

  19. An amorphous fluoropolymer: Next generation optical coating candidate

    SciTech Connect

    Chow, R.; Loomis, G.E.; Spragge, M.K.; Lindsey, E.L.; Rainer, F.; Ward, R.L.; Kozlowski, M.R.

    1994-05-01

    Anti-reflective (AR) and high reflector (HR) optical coatings were made by physical vapor deposition (PVD) of Teflon AF2400, a perfluorinated amorphous polymer. The AR had the highest laser damage thresholds recorded for PVD coatings at the Lawrence Livermore National Laboratory damage facility. The HR was a multilayer of ZnS and AF2400. The bandwidth was 550 mn, centered at 1064 mn. Single layers of Teflon AF2400 deposited by PVD were characterized optically. The refractive index could be intentionally reduced below the bulk value by varying either deposition rate or substrate temperature. Scanning electron microscopy and nuclear magnetic resonance observations indicated that morphological changes caused the variations in the refractive index rather than compositional changes.

  20. Nanoporous Aluminum Oxide Membranes Coated with Atomic Layer Deposition-Grown Titanium Dioxide for Biomedical Applications: An In Vitro Evaluation.

    PubMed

    Petrochenko, Peter E; Kumar, Girish; Fu, Wujun; Zhang, Qin; Zheng, Jiwen; Liang, Chengdu; Goering, Peter L; Narayan, Roger J

    2015-12-01

    The surface topographies of nanoporous anodic aluminum oxide (AAO) and titanium dioxide (TiO2) membranes have been shown to modulate cell response in orthopedic and skin wound repair applications. In this study, we: (1) demonstrate an improved atomic layer deposition (ALD) method for coating the porous structures of 20, 100, and 200 nm pore diameter AAO with nanometer-thick layers of TiO2 and (2) evaluate the effects of uncoated AAO and TiO2-coated AAO on cellular responses. The TiO2 coatings were deposited on the AAO membranes without compromising the openings of the nanoscale pores. The 20 nm TiO2-coated membranes showed the highest amount of initial protein adsorption via the micro bicinchoninic acid (micro-BCA) assay; all of the TiO2-coated membranes showed slightly higher protein adsorption than the uncoated control materials. Cell viability, proliferation, and inflammatory responses on the TiO2-coated AAO membranes showed no adverse outcomes. For all of the tested surfaces, normal increases in proliferation (DNA content) of L929 fibroblasts were observed over from 4 hours to 72 hours. No increases in TNF-alpha production were seen in RAW 264.7 macrophages grown on TiO2-coated AAO membranes compared to uncoated AAO membranes and tissue culture polystyrene (TCPS) surfaces. Both uncoated AAO membranes and TiO2-coated AAO membranes showed no significant effects on cell growth and inflammatory responses. The results suggest that TiO2-coated AAO may serve as a reasonable prototype material for the development of nanostructured wound repair devices and orthopedic implants.

  1. Reflective Coating for Lightweight X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Chan, Kai-Wing; Zhang, William W.; Windt, David; Hong, Mao-Ling; Saha, Timo; McClelland, Ryan; Sharpe, Marton; Dwivedi, Vivek H.

    2012-01-01

    X-ray reflective coating for next generation's lightweight, high resolution, optics for astronomy requires thin-film deposition that is precisely fine-tuned so that it will not distort the thin sub-mm substrates. Film of very low stress is required. Alternatively, mirror distortion can be cancelled by precisely balancing the deformation from multiple films. We will present results on metallic film deposition for the lightweight optics under development. These efforts include: low-stress deposition by magnetron sputtering and atomic layer deposition of the metals, balancing of gross deformation with two-layer depositions of opposite stresses and with depositions on both sides of the thin mirrors.

  2. Optical fibre hydrogen sensors based on palladium coatings

    NASA Astrophysics Data System (ADS)

    Coelho, L.; Silva, S. F. O.; Tafulo, Paula A. R.; Santos, J. L.; Frazão, O.; Malcata, F. X.

    2011-05-01

    Optical fibre sensors for Hydrogen detection at low concentrations has become a growing research area using Palladium as an active medium. Palladium is widely used in hydrogen sensing as it show a high and selective affinity for hydrogen. This metal is capable to absorb hydrogen up to 900 times its own volume which permits that during the expansion mechanical forces are applied in the fibre modifying the optical response. Several optical fibre hydrogen sensor heads coated with Palladium are presented and compared using different working principles: interferometric, intensity and fiber grating-based sensors. These principles were applied in Fabry-Perot cavities, fibre Bragg gratings written in fibre SMF28 with etching in the cladding, multimode interferometers and fibre end micro-mirrors. Palladium thin film coatings over the fibre surface and with thicknesses from 10nm to 350nm were produced by using the sputtering RF technique. These studies were performed in a Hydrogen/Nitrogen atmosphere with Hydrogen concentrations from 0% to 4% (lower limit explosion). The Bragg grating inscribed in a fibre with reduced cladding diameter appears to be one of the best approaches for a fibre optic sensing head for Hydrogen detection. Future work will continue the investigation of other fibre optic structures with Hydrogen sensing capabilities and their application in specific field situations will be assessed.

  3. Sol-gel optical coatings for lasers, 2

    SciTech Connect

    Floch, H.G.; Belleville, P.F.; Priotton, J.J.; Pegon, P.M.; Dijonneau, C.S.; Guerain, J.

    1995-11-01

    There are three basic types of antireflective (AR) coatings. The first is a single-layer coating in which the coating index is equal to the square root of the index of the substrate, assuming air is the external medium. The second type is a system of two or more layers of different indexes. The third type is a graded-index system, where the index is uniformly and continuously graded from the substrate to the external medium. Low reflection ranges from narrow for the single-layer to broad for the graded-layer and multilayered with a large number of layers. Four types of sol-gel AR coatings have been developed at CEL-V. They are based on single-layer or multilayer designs. They consist mainly of amorphous silica in the polymeric and/or colloidal state, combined in certain cases with other metallic oxides, binders, fillers, hydrophobic and lubricating agents, and adhesion promoters. These antireflective sol-gel-derived optical coatings have been prepared and tested for the proposed French megajoule neodymium-glass laser.

  4. Influences of oil-contamination on LIDT and optical properties in dielectric coatings

    NASA Astrophysics Data System (ADS)

    Murakami, H.; Jitsuno, T.; Motokoshi, S.; Sato, E.; Mikami, K.; Kato, K.; Kawasaki, T.; Nakata, Y.; Sarukura, N.; Shinizu, T.; Shiraga, H.; Miyanaga, N.; Azechi, H.

    2012-11-01

    Laser-induced damage threshold (LIDT) in optical coating is very sensitive to organic contaminations accumulated in coating layers during storage and using condition. The sources of contamination are commonly exists, and optical coatings are easily contaminated regardless to the environment pressure, LIDT at ns region decreased largely by contamination, but LIDT at ps seems insensitive. In this study, we have investigated the influence of contamination of optical coating on LIDT and other optical properties. We examined several kinds of coating to clarify the sensitivity to the contamination. Degradations of LIDT were commonly observed in e-beam deposition, IAD and IBS. Some coatings changed spectral characteristics by contamination, and other coatings did not change. Some samples were contaminated as received condition, and some were very clean. Furthermore, we have investigated the characteristics of LIDT in dielectric coatings under the controlled contamination. LIDT of coating drops to 1/2 in the saturated toluene vapor at room temperature.

  5. Electrochemical detection of uric acid using ruthenium-dioxide-coated carbon nanotube directly grown onto Si wafer

    NASA Astrophysics Data System (ADS)

    Shih, Yi-Ting; Lee, Kuei-Yi; Lin, Chung-Kuang

    2015-12-01

    Carbon nanotubes (CNTs) directly grown onto a Si substrate by thermal chemical vapor deposition were used in uric acid (UA) detection. The process is simple and formation is easy without the need for additional chemical treatments. However, CNTs lack selectivity and sensitivity to UA. To enhance the electrochemical analysis, ruthenium oxide was used as a catalytic mediator in the modification of electrodes. The electrochemical results show that RuO2 nanostructures coated onto CNTs can strengthen the UA signal. The peak currents of RuO2 nanostructures coated onto CNTs linearly increase with increasing UA concentration, meaning that they can work as electrodes for UA detection. The lowest detection limit and highest sensitivity were 55 nM and 4.36 µA/µM, respectively. Moreover, the characteristics of RuO2 nanostructures coated onto CNTs were examined by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy.

  6. Annealing of indium tin oxide (ITO) coated optical fibers for optical and electrochemical sensing purposes

    NASA Astrophysics Data System (ADS)

    Dominik, Magdalena; Siuzdak, Katarzyna; Niedziałkowski, Paweł; Stranak, Vitezslav; Sezemsky, Petr; Sobaszek, Michał; Bogdanowicz, Robert; Ossowski, Tadeusz; Śmietana, Mateusz

    2016-12-01

    Glass and fiber structures with Indium Tin Oxide (ITO) coating were subjected to annealing in order to identify impact of the thermal treatment on their optical and electrochemical properties. It is shown that the annealing process significantly modifies optical properties and thickness of the films, which are crucial for performance of optical fiber sensors. Moreover, it visibly improves electrochemical activity of ITO on glass slides and thicker (∅=400 μm) ITO-coated fibers, whereas in the case of thinner fibers (∅=125 μm) it could lead to a loss of their electrochemical activity. Depending on the applied substrate and the annealing process, the investigated structures with ITO coating can be further used as fiber-based sensors with integrated opto-electrochemical readout.

  7. Optical, mechanical and thermal characterization of l-threonine single crystals grown in dimethyl urea solution

    NASA Astrophysics Data System (ADS)

    Shanthi, A.; Krishnan, C.; Selvarajan, P.

    2013-09-01

    An organic material of a noncentrosymmetric l-threonine single crystal was grown in a dimethyl urea solution using the slow evaporation method. The grown crystal was transparent and colorless, with a size of about 20 × 7 × 4 mm3, obtained within a period of 10 days. The grown crystal was subjected to various studies, such as x-ray diffraction (XRD), Fourier transform infrared (FTIR), microhardness, ultraviolet-visible (UV-Vis) transmittance, thermogravimetric analysis and differential thermal analysis (TGA/DTA) and second harmonic generation (SHG). l-threonine crystals grown in a dimethyl urea solution show relative SHG efficiency of 0.92 times that of potassium dihydrogen phosphate. The functional groups of the crystals have been confirmed by FTIR analysis. The mechanical strength of the crystal was estimated by the Vickers hardness test. The lattice parameters of the grown crystal were determined by single crystal XRD and powder XRD studies, and the diffraction peaks were indexed. A UV-Vis spectrum was recorded in the wavelength range of 200-1100 nm to find the suitability of the crystal for nonlinear optical applications. The thermal stability of l-threonine crystal grown in dimethyl urea was checked using the TGA/DTA analysis.

  8. Residual stress and dislocations density in silicon ribbons grown via optical zone melting

    NASA Astrophysics Data System (ADS)

    Augusto, A.; Pera, D.; Choi, H. J.; Bellanger, P.; Brito, M. C.; Maia Alves, J.; Vallêra, A. M.; Buonassisi, T.; Serra, J. M.

    2013-02-01

    We investigate the relationships between growth rate, time-temperature profile, residual stress, dislocation density, and electrical performance of silicon ribbons grown via optical zone melting. The time-temperature profiles of ribbons grown at different velocities were investigated using direct measurements and computational fluid dynamics (CFD) modeling. Residual stresses up to 20 MPa were measured using infrared birefringence imaging. The effect of crystallization speed on dislocation density and residual stress is discussed from the context of thermal stresses during growth. More broadly, we demonstrate the usefulness of combining spatially resolved stress and microstructure measurements with CFD simulations toward optimizing kerfless silicon wafer quality.

  9. Fatigue behavior of polyimide coated optical fibers at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Huang, Lei; Dyer, Robert S.; Li, Jie

    2017-02-01

    As optical fiber is being used in much harsher environments than traditional telecommunications (e.g. distributed temperature sensing at elevated temperatures) understanding its mechanical properties at high temperatures is urgently needed. As a continuation of our previous work on high temperature strength of silica optical fiber, we report our results in fatigue behavior of polyimide coated silica optical fiber at 300°C in this paper. Fiber fatigue is the degradation in strength caused by a stress dependent chemical reaction between water vapor and the surface of the silica glass. In contrast to the published data on degradation in mechanical properties of silica optical fiber at elevated temperatures, our observations indicate a negligible decrease in strength along with unchanged, n-value, (fatigue resistant factor) at 300°C. To determine the n value, we tested tensile strength of the fiber using four different strain rates while the subject under test was at 300°C. The results indicate that the polyimide coating on the silica glass fiber continues to serve as an effective water vapor barrier at 300°C. These results will be compared with data available for room temperature performance of this silica/polyimide combination and possible failure mechanisms will be discussed.

  10. 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.

  11. Evaluation of the Solutions for two Design Problems Presented at the 1998 Optical Interference Coatings Conference.

    PubMed

    Baumeister, P

    2000-05-01

    Two problems were proposed at the 1998 Conference on Optical Interference Coatings: dual-band antireflection coatings and bandpass filters. In excess of 40 solutions were submitted. An evaluation of those solutions is presented.

  12. Gold Coating of Fiber Tips in Near-Field Scanning Optical Microscopy

    NASA Technical Reports Server (NTRS)

    Vikram, Chandra S.; Witherow, William K.

    2000-01-01

    We report what is believed to be the first experimental demonstration of gold coating by a chemical baking process on tapered fiber tips used in near-field scanning optical microscopy. Many tips can be simultaneously coated.

  13. Gold Coating of Fiber Tips in Near-Field Scanning Optical Microscopy

    NASA Technical Reports Server (NTRS)

    Vikram, Chandra S.; Witherow, William K.

    2000-01-01

    We report what is believed to be the first experimental demonstration of gold coating by a chemical baking process on tapered fiber tips used in near-field scanning optical microscopy. Many tips can be simultaneously coated.

  14. Topical meeting on optical interference coatings (OIC'2001): manufacturing problem.

    PubMed

    Dobrowolski, J A; Browning, Stephen; Jacobson, Michael; Nadal, Maria

    2002-06-01

    Measurements are presented of the experimental filters submitted to the first optical thin-film manufacturing problem posed in conjunction with the Topical Meeting on Optical Interference Coatings, in which the object was to produce multilayers with spectral transmittance and reflectance curves that were as close as possible to the target values that were specified in the 400- to 600-nm spectral region. No limit was set on the overall thickness of the solutions or the number of layers used in their construction. The participants were free to use the coating materials of their choice. Six different groups submitted a total of 11 different filters for evaluation. Three different physical vapor deposition processes were used for the manufacture of the coatings: magnetron sputtering, ion-beam sputtering, and plasma-ion-assisted, electron-beam gun evaporation. The solutions ranged in metric thickness from 758 to 4226 nm and consisted of between 8 and 27 layers. For all but two of the samples submitted, the average rms departure of the measured transmittances and reflectances from the target values in the spectral region of interest was between 0.98% and 1.55%.

  15. Optical properties of lithium fluoride fibers grown by micro-pulling-down method

    NASA Astrophysics Data System (ADS)

    Santo, A. M. E.; Courrol, L. C.; Ranieri, I. M.; Wetter, N. U.; Vieira, N. D.; Baldochi, S. L.

    2004-12-01

    Fluoride single-crystalline fibers were grown by the micro-pulling-down (μ-PD) technique. The optical properties of the LiF fiber and the bulk crystal (grown by Czochralski technique) were compared. Both samples were irradiated with 40 Mrad of gamma rays at room temperature and color centers were successfully produced. The emission spectra of the fiber and the bulk crystal when excited at 447 nm show the typical broad emission bands related to the F3+ and F2 centers, with peaks at 535 and 650 nm, respectively. Both spectra contain a very strong emission band centered at 1120 nm with the same half width of 1350 cm-1 when excited with a InGaAs diode laser at 968 nm. These results indicate a potential use of these new LiF fibers in miniaturized active optical devices.

  16. Optical absorption enhancement in 3D nanofibers coated on polymer substrate for photovoltaic devices.

    PubMed

    Kiani, Amirkianoosh; Venkatakrishnan, Krishnan; Tan, Bo

    2015-06-01

    Recent research in the field of photovoltaics has shown that polymer solar cells have great potential to provide low-cost, lightweight and flexible electronic devices to harvest solar energy. In this paper, we propose a new method for the generation of three-dimensional nanofibers coated on polymer substrate induced by femtosecond laser pulses. In this new method, a thin layer of polymer is irradiated by megahertz femtosecond laser pulses under ambient conditions, and a thin fibrous layer is generated on top of the polymer substrate. This method is single step; no additional materials are added, and the layers of the three-dimensional (3D) polymer nanofibrous structures are grown on top of the substrate after laser irradiation. Light spectroscopy results show significant enhancement of light absorption in the generated 3D nanofibrous layers of polymer. Finally, we suggest how to maximize the light trapping and optical absorption of the generated nanofiber cells by optimizing the laser parameters.

  17. On physical optics for calculating scattering from coated bodies

    NASA Technical Reports Server (NTRS)

    Baldauf, J.; Lee, S. W.; Ling, H.; Chou, R.

    1989-01-01

    The familiar physical optics (PO) approximation is no longer valid when the perfectly conducting scatterer is coated with dielectric material. This paper reviews several possible PO formulations. By comparing the PO formulation with the moment method solution based on the impedance boundary condition for the case of the coated cone-sphere, a PO formulation using both electric and magnetic currents consistently gives the best numerical results. Comparisons of the exact moment method with the PO formulations using the impedance boundary condition and the PO formulation using the Fresnel reflection coefficient for the case of scattering from the cone-ellipsoid demonstrate that the Fresnel reflection coefficient gives the best numerical results in general.

  18. Buckling conditions for a dual-coated optical fiber

    NASA Astrophysics Data System (ADS)

    Suhir, Ephraim

    2013-03-01

    The elastic stability (buckling) condition for a short dual-coated optical-fiber experiencing mechanical and/or thermally induced compression is established based on the developed analytical (mathematical) predictive model. The problem is reduced to a situation when a cantilever beam of finite length is supported by a continuous elastic foundation and is subjected to a compressive force applied to the beam's free end. Easy-to-use practical guidelines and a simple diagram are suggested for choosing the adequate length of the fiber and/or its flexural rigidity and/or the characteristics of the coating materials, so that the fiber remains elastically stable. The developed model can be used also in the design and reliability evaluations of composites, including nano-composites, and in flexible (large area) photonics when high-modulus and lowexpansion fibers are embedded into a high-modulus-and-low-expansion matrix and experience axial compression at low temperature conditions.

  19. Optical, structural and microhardness properties of KDP crystals grown from urea-doped solutions

    SciTech Connect

    Pritula, I. Kosinova, A.; Kolybayeva, M.; Puzikov, V.; Bondarenko, S.; Tkachenko, V.; Tsurikov, V.; Fesenko, O.

    2008-10-02

    Potassium dihydrophosphate single crystals were grown from aqueous solutions onto a point seed using temperature reduction method by doping with different molar values of urea. The characterization of the grown crystals was made by visible and Fourier transform infrared spectroscopy, Vicker's hardness studies, X-ray powder diffraction, non-linear optical and laser damage threshold measurements. By comparing these crystals with the ones grown from the pure solution, it is shown that 0.2-2.0 M of the urea additive enhances the laser damage threshold and the second harmonic efficiency more than by 25 and 20%, respectively. By means of the Bond method using a multipurpose three-crystal X-ray diffractometer it is shown that the presence of urea additive increases the crystal lattice parameter c of the grown crystals, whereas the lattice parameter a is by an order less sensitive to the changing urea concentration in the solution. The Vicker's hardness studies at room temperature carried out on (1 0 0) and (0 0 1) crystallographic planes show an increased hardness of the doped crystals (grown in the presence of urea additive) on the plane (0 0 1) in comparison with that of pure potassium dihydrophosphate crystal.

  20. Optical Coherence Tomography and Optical Coherence Tomography Angiography in Monitoring Coats' Disease

    PubMed Central

    Hautz, Wojciech; Kocyła-Karczmarewicz, Beata

    2017-01-01

    Purpose. The aim of this study was to evaluate the usefulness of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in monitoring pediatric patients with Coats' disease. Material and Methods. This retrospective study included 9 Caucasian patients receiving treatment for Coats' disease at the Children's Memorial Health Institute Ophthalmology Department between December 2014 and May 2016. The course of the disease was monitored with OCTA in combination with OCT and fluorescein angiography (FA). Results. OCT B-scans obtained in all patients correlated with FA findings. Reliable OCTA images were obtained in 8 patients. In one patient, numerous artifacts due to poor visual acuity and retinal detachment confounded the interpretation of findings. Conclusions. OCTA and OCT, in combination with FA, are useful in Coats' disease diagnostics and treatment monitoring. As noninvasive methods, OCT and OCTA may be performed more often than FA, which enable precise monitoring of the disease and making decisions as to its further treatment. PMID:28377823

  1. Photo-induced reduction of graphene oxide coating on optical waveguide and consequent optical intermodulation

    PubMed Central

    Chong, W. Y.; Lim, W. H.; Yap, Y. K.; Lai, C. K.; De La Rue, R. M.; Ahmad, H.

    2016-01-01

    Increased absorption of transverse-magnetic (TM) - polarised light by a graphene-oxide (GO) coated polymer waveguide has been observed in the presence of transverse-electric (TE) - polarised light. The GO-coated waveguide exhibits very strong photo-absorption of TE-polarised light - and acts as a TM-pass waveguide polariser. The absorbed TE-polarised light causes a significant temperature increase in the GO film and induces thermal reduction of the GO, resulting in an increase in optical-frequency conductivity and consequently increased optical propagation loss. This behaviour in a GO-coated waveguide gives the action of an inverted optical switch/modulator. By varying the incident TE-polarised light power, a maximum modulation efficiency of 72% was measured, with application of an incident optical power level of 57 mW. The GO-coated waveguide was able to respond clearly to modulated TE-polarised light with a pulse duration of as little as 100 μs. In addition, no wavelength dependence was observed in the response of either the modulation (TE-polarised light) or the signal (TM-polarised light). PMID:27034015

  2. Optical coatings in microscale channels by atomic layer deposition.

    PubMed

    Gabriel, Nicholas T; Talghader, Joseph J

    2010-03-10

    High-aspect-ratio channels may be coated using atomic layer deposition (ALD) due to the unique self-limiting nature of the process, and this has been often demonstrated using deep reactive-ion etched trenches in silicon. However, for optical and microfluidic applications, many channels are centimeters deep with diameters of tens to hundreds of micrometers, and the relatively large area exposes more difficult problems of temperature and gas flow uniformity. To quantify the uniformity of optical coatings deposited by ALD under those conditions, an air wedge has been created between two square wafers of silicon approximately 7 cm on a side, with the air gap varying linearly from 0-1560 microm. ALD aluminum oxide uniformity is astounding, while hafnium oxide shows a need for process optimization, but still exceeds the capability observed in other deposition techniques. A six-layer Fabry-Perot optical cavity with fixed 500 nm resonance was deposited inside a wedge, and the measured resonant wavelength closely matched predictions, except at the deepest regions of the wedge.

  3. Strong nonlinear optical enhancement in MBE-grown Bi 1-xSb x

    NASA Astrophysics Data System (ADS)

    Youngdale, E. R.; Meyer, J. R.; Hoffman, C. A.; Bartoli, F. J.; Partin, D. L.; Thrush, C. M.; Heremans, J. P.

    1991-05-01

    We report an experimental study of the linear and nonlinear optical properties of Bi 1-xSb x alloy layers grown by MBE. Non-degenerate four-wave mixing experiments at CO 2 laser wavelengths yield a large third-order nonlinear susceptibility (χ (3)≈3.5 × 10 -4 esu). Furthermore, due to the high reflectivity of the Bi 1-xSb x films at both the air and substrate interfaces, the etalon formed can enhance the nonlinear optical signal by over an order of magnitude.

  4. Optical fiducial timing system for X-ray streak cameras with aluminum coated optical fiber ends

    DOEpatents

    Nilson, David G.; Campbell, E. Michael; MacGowan, Brian J.; Medecki, Hector

    1988-01-01

    An optical fiducial timing system is provided for use with interdependent groups of X-ray streak cameras (18). The aluminum coated (80) ends of optical fibers (78) are positioned with the photocathodes (20, 60, 70) of the X-ray streak cameras (18). The other ends of the optical fibers (78) are placed together in a bundled array (90). A fiducial optical signal (96), that is comprised of 2.omega. or 1.omega. laser light, after introduction to the bundled array (90), travels to the aluminum coated (82) optical fiber ends and ejects quantities of electrons (84) that are recorded on the data recording media (52) of the X-ray streak cameras (18). Since both 2.omega. and 1.omega. laser light can travel long distances in optical fiber with only a slight attenuation, the initial arial power density of the fiducial optical signal (96) is well below the damage threshold of the fused silica or other material that comprises the optical fibers (78, 90). Thus the fiducial timing system can be repeatably used over long durations of time.

  5. Optical characterization of synthetic faceted gem materials grown from hydrothermal solutions

    NASA Astrophysics Data System (ADS)

    Lu, Taijin; Shigley, James E.

    1998-10-01

    Various non-destructive optical characterization techniques have been used to characterize and identify synthetic gem materials grown from hydrothermal solutions, to include ruby, sapphire, emerald, amethyst and ametrine (amethyst-citrine), from their natural counterparts. The ability to observe internal features, such as inclusions, dislocations, twins, color bands, and growth zoning in gem materials is strongly dependent on the observation techniques and conditions, since faceted gemstones have many polished surfaces which can reflect and scatter light in various directions which can make observation difficult. However, diagnostic gemological properties of these faceted synthetic gem materials can be obtained by choosing effective optical characterization methods, and by modifying optical instruments. Examples of some of the distinctive features of synthetic amethyst, ametrine, pink quartz, ruby and emerald are presented to illustrate means of optical characterization of gemstones. The ability to observe defects by light scattering techniques is discussed.

  6. Impact of low temperature annealing on structural, optical, electrical and morphological properties of ZnO thin films grown by RF sputtering for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Purohit, Anuradha; Chander, S.; Sharma, Anshu; Nehra, S. P.; Dhaka, M. S.

    2015-11-01

    This paper presents effect of low temperature annealing on the physical properties of ZnO thin films for photovoltaic applications. The thin films of thickness 50 nm were grown on glass and indium tin oxide (ITO) coated glass substrates employing radio frequency magnetron sputtering technique followed by thermal annealing within low temperature range 150-450 °C. These as-grown and annealed films were subjected to the X-ray diffraction (XRD), UV-Vis spectrophotometer, source meter and scanning electron microscopy (SEM) for structural, optical, electrical and surface morphological analysis respectively. The compositional analysis of the as-grown ZnO film was also carried out using energy dispersive spectroscopy (EDS). The XRD patterns reveal that the films have wurtzite structure of hexagonal phase with preferred orientation (1 0 0) and polycrystalline in nature. The crystallographic and optical parameters are calculated and discussed in detail. The optical band gap was found in the range 3.30-3.52 eV and observed to decrease with annealing temperature except 150 °C. The current-voltage characteristics show that the films exhibit approximately ohmic behavior. The SEM studies show that the films are uniform, homogeneous and free from crystal defects and voids. The experimental results reveal that ZnO thin films may be used as alternative materials for eco-friendly buffer layer to the thin film solar cell applications.

  7. Reflection coefficient monitoring for optical interference coating depositions.

    PubMed

    Lee, Cheng-Chung; Wu, Kai; Ho, Meng-Yen

    2013-04-15

    The real-time reflection coefficient (both of the reflection phase and the amplitude) at normal incidence of a single wavelength was acquired from the real-time spectrum of a broadband optical monitor. This is a powerful monitoring technique for multilayer interference coatings. The monitoring method shows high stability and good error compensation ability without deposition termination ambiguity. The experiments demonstrated that reflection coefficient monitoring has remarkable performance compared with other monitoring methods. Without changing the monitoring chip, the conventional broadband monitoring was improved 82% closer to the design by the proposed monitoring method.

  8. 2007 topical meeting on optical interference coatings: manufacturing problem.

    PubMed

    Dobrowolski, J A; Browning, Stephen; Jacobson, Michael; Nadal, Maria

    2008-05-01

    Measurements are described on the experimental filters submitted to the Third Optical Thin Film Manufacturing Problem in which the object was to produce multilayers with a measured colorimetric performance that is as close as possible to that specified. The perceived colors of the coating, when illuminated with randomly polarized light incident at 7 degrees by a source representing average daylight with a correlated color temperature of approximately 6500 K, were to be yellow and blue, respectively, in light reflected from its two surfaces, and the color was to appear white when viewed in transmission mode. Eleven teams from 7 different countries submitted a total of 18 samples.

  9. The first aluminum coating of the 3700mm primary mirror of the Devasthal Optical Telescope

    NASA Astrophysics Data System (ADS)

    Bheemireddy, Krishna Reddy; Gopinathan, Maheswar; Pant, Jayshreekar; Omar, Amitesh; Kumar, Brijesh; Uddin, Wahab; Kumar, Nirmal

    2016-07-01

    Initially the primary mirror of the 3.6m Devasthal Optical Telescope is uncoated polished zerodur glass supplied by Lytkarino Optical Glass Factory, Russia/Advanced Mechanical and Optical Systems, Belgium. In order to do the aluminium coating on the primary mirror the coating plant including washing unit is installed near the telescope (extension building of telescope) by Hind High Vacuum (HHV) Bangalore, India. Magnetron sputtering technique is used for the coating. Several coating trials are done before the primary mirror coating; samples are tested for reflectivity, uniformity, adhesivity and finally commissioned. The primary mirror is cleaned, coated by ARIES. We present here a brief description of the coating plant installation, Mirror cleaning and coating procedures and the testing results of the samples.

  10. Optical properties of black carbon aggregates with non-absorptive coating

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Li, Ji; Yin, Yan; Zhu, Bin; Feng, Qian

    2017-01-01

    This study develops an idealized model to account for the effects of non-absorptive coating on the optical properties of black carbon (BC) aggregates. The classic fractal aggregate is applied to represent realistic BC particles, and the coating is assumed to be spherical. To accelerate the single-scattering simulation, BC monomers that were overlapped with coating sphere (not those completely inside the coating) are slightly moved to avoid overlapping. The multiple-sphere T-matrix method (MSTM) becomes applicable to calculate the optical properties of inhomogeneous particles with any coating amount, and is generally two orders of magnitude faster than the discrete-dipole approximation for particles we considered. Furthermore, the simple spherical coating is found to have similar effects on the optical properties to those based on more complicated coating structure. With the simple particle model and the efficient MSTM, it becomes possible to consider the influence of coating with much more details. The non-absorptive coating of BC aggregates can significantly enhance BC extinction and absorption, which is consistent with previous studies. The absorption of coated aggregates can be over two times stronger than that of BC particles without coating. Besides the coating volume, the relative position between the mass centers of BC aggregate and coating also plays an important role on the optical properties, and should obviously be considered in further studies.

  11. Optical Diagnostics for High-Temperature Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Eldridge, Jeffrey I.

    2009-01-01

    Thermal barrier coatings (TBCs) are typically composed of translucent ceramic oxides that provide thermal protection for metallic components exposed to high-temperature environments, such as in jet turbine engines. Taking advantage of the translucent nature of TBCs, optical diagnostics have been developed that can provide an informed assessment of TBC health that will allow mitigating action to be taken before TBC degradation threatens performance or safety. In particular, rare-earth-doped luminescent sublayers have been integrated into the TBC structure to produce luminescence that monitors TBC erosion, delamination, and temperature gradients. Erosion monitoring of TBC-coated specimens is demonstrated by utilizing visible luminescence that is excited from a sublayer that is exposed by erosion. TBC delamination monitoring is achieved in TBCs with a base rare-earth-doped luminescent sublayer by the reflectance-enhanced increase in luminescence produced in regions containing buried delamination cracks. TBC temperature monitoring is demonstrated using the temperature-dependent decay time for luminescence originating from the specific coating depth associated with a rare-earth-doped luminescent sublayer. The design and implementation of these TBCs with integrated luminescent sublayers is discussed, including co-doping strategies to produce more penetrating near-infrared luminescence. It is demonstrated that integration of the rare-earth-doped sublayers is achieved with no reduction in TBC life. In addition, results for multilayer TBCs designed to also perform as radiation barriers are also presented.

  12. Fabrication of optical element from unidirectional grown imidazole-imidazolium picrate monohydrate (IIP) organic crystals for nonlinear optical applications

    NASA Astrophysics Data System (ADS)

    Vivek, P.; Murugakoothan, P.

    2014-12-01

    Nonlinear optical bulk single crystal of Imidazole-imidazolium picrate monohydrate (IIP) has been grown by Sankaranarayanan-Ramasamy (SR) method using acetonitrile as solvent. First time we report the bulk growth of IIP crystal by SR method. The transparent IIP single crystal of maximum diameter 21 mm and length 46 mm was obtained by employing SR method. The grown crystal was subjected to high resolution X-ray diffraction, UV-vis-NIR transmittance, refractive index, hardness, dielectric and laser damage threshold studies. The crystalline perfection of the grown crystal was analyzed using HRXRD. Cut off wavelength and optical transmission window of the crystal was assessed by UV-vis-NIR and the refractive index of the crystal was found. The mechanical property of the crystal was estimated by Vicker's hardness test. The dielectric property of the crystal was measured as a function of frequency. The laser damage threshold value was determined. The particle size dependent second harmonic generation efficiency for IIP was evaluated with standard reference material potassium dihydrogen phosphate (KDP) by Kurtz-Perry powder method using Nd:YAG laser, which established the existence of phase matching. The second harmonic generation (SHG) of IIP crystal was investigated by the SHG Maker fringes technique. The mechanism of growth is revealed by carrying out chemical etching using acetonitrile as etchant.

  13. Optical stent inspection of surface texture and coating thickness

    NASA Astrophysics Data System (ADS)

    Bermudez, Carlos; Laguarta, Ferran; Cadevall, Cristina; Matilla, Aitor; Ibañez, Sergi; Artigas, Roger

    2017-02-01

    Stent quality control is a critical process. Coronary stents have to be inspected 100% so no defective stent is implanted into a human body. We have developed a high numerical aperture optical stent inspection system able to acquire both 2D and 3D images. Combining a rotational stage, an area camera with line-scan capability and a triple illumination arrangement, unrolled sections of the outer, inner, and sidewalls surfaces are obtained with high resolution. During stent inspection, surface roughness and coating thickness uniformity is of high interest. Due to the non-planar shape of the surface of the stents, the thickness values of the coating need to be corrected with the 3D surface local slopes. A theoretical model and a simulation are proposed, and a measurement with white light interferometry is shown. Confocal and spectroscopic reflectometry showed to be limited in this application due to stent surface roughness. Due to the high numerical aperture of the optical system, only certain parts of the stent are in focus, which is a problem for defect detection, specifically on the sidewalls. In order to obtain fully focused 2D images, an extended depth of field algorithm has been implemented. A comparison between pixel variance and Laplacian filtering is shown. To recover the stack image, two different methods are proposed: maximum projection and weighted intensity. Finally, we also discuss the implementation of the processing algorithms in both the CPU and GPU, targeting real-time 2-Million pixel image acquisition at 50 frames per second.

  14. Microstructure, mechanical and optical properties of TiAlON coatings sputter-deposited with varying oxygen partial pressures

    NASA Astrophysics Data System (ADS)

    Schalk, Nina; Thierry Simonet Fotso, J. F.; Holec, David; Fian, Alexander; Jakopic, Georg; Terziyska, Velislava L.; Daniel, Rostislav; Mitterer, Christian

    2016-01-01

    Due to their excellent mechanical and optical properties as well as chemical stability, the synthesis of transition metal oxynitride thin films has attracted growing interest in the last years. Within this work, the evolution of the structure and properties of TiAlON coatings over a wide compositional range, from the nitride to the oxide side, was investigated. The coatings were grown on Si substrates in a laboratory-scale unbalanced magnetron dc sputtering system from powder metallurgical TiAl targets with an Al/Ti atomic ratio of 60/40, using a constant level of nitrogen with rising oxygen partial pressure. Coating composition and microstructure were investigated by energy- and wavelength-dispersive x-ray spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy, Raman spectroscopy and transmission electron microscopy. Furthermore, the mechanical and optical properties were evaluated using nanoindentation and spectroscopic ellipsometry, respectively. Oxygen concentrations of up to 49 at.% within the films could be obtained, at the expense of the nitrogen content. The oxygen-free coating exhibited a single-phase fcc-Ti1-x Al x N structure. With increasing oxygen content the structure remained fcc-Ti1-x Al x N based, but additional fractions of amorphous oxides were formed. The structural evolution was corroborated by ab initio calculations. Decreasing coating hardness could be observed with increasing oxygen concentration. The refraction index and extinction coefficient were lower for coatings with higher oxygen content, but the behavior of the optical properties remained Ti1-x Al x N-like over the investigated spectral range.

  15. Characterization of GaAlAs optical waveguide heterostructures grown by molecular beam epitaxy

    NASA Technical Reports Server (NTRS)

    Radens, C. J.; Jackson, H. E.; Boyd, J. T.; Bhasin, K. B.; Pouch, J. J.

    1988-01-01

    Multiple-layer GaAlAs optical waveguide heterostructures have been grown by MBE. These samples were designed to operate at 840 nm with negligible coupling of guided light to the absorbing GaAs substrate. The Al concentration was 13 percent for the guiding layer and was 16 percent for the cladding layers. The process for growing waveguide layers was calibrated primarily by high-energy electron diffraction, with the optical quality confirmed by photoluminescence measurements. Channel waveguide structures having widths of 5 microns were etched in a low-pressure magnetically confined multipolar plasma reactor. The resulting waveguide structures were characterized by Raman spectroscopy, ellipsometry, AES, and optical-waveguide loss measurements.

  16. Structural and optical properties of PbS thin films grown by chemical bath deposition

    SciTech Connect

    Seghaier, S.; Kamoun, N.; Guasch, C.; Zellama, K.

    2007-09-19

    Lead sulphide thin films are grown on glass substrates at various deposition times tD, in the range of 40-60 min per step of 2 min, using the chemical bath deposition technique. X-ray diffraction and atomic force microscopy are used to characterize the film structure. The surface composition is analysed by Auger electron spectroscopy. It appears that the as-prepared thin films are polycrystalline with cubic structure. Nanometric scale crystallites are uniformly distributed on the surface. They exhibit almost a stoechiometric composition with a [Pb]/[S] ratio equal to 1.10. Optical properties are studied in the range of 300-3300 nm by spectrophotometric measurements. Analysis of the optical absorption data of lead sulphide thin layers reveals a narrow optical direct band gap equal to 0.46 eV for the layer corresponding to a deposition time equal to 60 min.

  17. Figuring large optics at the sub-nanometer level: compensation for coating and gravity distortions.

    PubMed

    Gensemer, Stephen; Gross, Mark

    2015-11-30

    Large, precision optics can now be manufactured with surface figures specified at the sub-nanometer level. However, coatings and gravity deform large optics, and there are limits to what can be corrected by clever compensation. Instead, deformations caused by stress from optical mounts and deposited coatings must be incorporated into the optical design. We demonstrate compensation of coating stress on a 370mm substrate to λ/200 by a process of coating and annealing. We also model the same process and identify the leading effects that must be anticipated in fabrication of optics for future gravitational wave detectors and other applications of large, precisely figured optics, and identify the limitations inherent in using coatings to compensate for these deformations.

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

  19. Large area Germanium Tin nanometer optical film coatings on highly flexible aluminum substrates

    PubMed Central

    Jin, Lichuan; Zhang, Dainan; Zhang, Huaiwu; Fang, Jue; Liao, Yulong; Zhou, Tingchuan; Liu, Cheng; Zhong, Zhiyong; Harris, Vincent G.

    2016-01-01

    Germanium Tin (GeSn) films have drawn great interest for their visible and near-infrared optoelectronics properties. Here, we demonstrate large area Germanium Tin nanometer thin films grown on highly flexible aluminum foil substrates using low-temperature molecular beam epitaxy (MBE). Ultra-thin (10–180 nm) GeSn film-coated aluminum foils display a wide color spectra with an absorption wavelength ranging from 400–1800 nm due to its strong optical interference effect. The light absorption ratio for nanometer GeSn/Al foil heterostructures can be enhanced up to 85%. Moreover, the structure exhibits excellent mechanical flexibility and can be cut or bent into many shapes, which facilitates a wide range of flexible photonics. Micro-Raman studies reveal a large tensile strain change with GeSn thickness, which arises from lattice deformations. In particular, nano-sized Sn-enriched GeSn dots appeared in the GeSn coatings that had a thickness greater than 50 nm, which induced an additional light absorption depression around 13.89 μm wavelength. These findings are promising for practical flexible photovoltaic and photodetector applications ranging from the visible to near-infrared wavelengths. PMID:27667259

  20. Large area Germanium Tin nanometer optical film coatings on highly flexible aluminum substrates

    NASA Astrophysics Data System (ADS)

    Jin, Lichuan; Zhang, Dainan; Zhang, Huaiwu; Fang, Jue; Liao, Yulong; Zhou, Tingchuan; Liu, Cheng; Zhong, Zhiyong; Harris, Vincent G.

    2016-09-01

    Germanium Tin (GeSn) films have drawn great interest for their visible and near-infrared optoelectronics properties. Here, we demonstrate large area Germanium Tin nanometer thin films grown on highly flexible aluminum foil substrates using low-temperature molecular beam epitaxy (MBE). Ultra-thin (10–180 nm) GeSn film-coated aluminum foils display a wide color spectra with an absorption wavelength ranging from 400–1800 nm due to its strong optical interference effect. The light absorption ratio for nanometer GeSn/Al foil heterostructures can be enhanced up to 85%. Moreover, the structure exhibits excellent mechanical flexibility and can be cut or bent into many shapes, which facilitates a wide range of flexible photonics. Micro-Raman studies reveal a large tensile strain change with GeSn thickness, which arises from lattice deformations. In particular, nano-sized Sn-enriched GeSn dots appeared in the GeSn coatings that had a thickness greater than 50 nm, which induced an additional light absorption depression around 13.89 μm wavelength. These findings are promising for practical flexible photovoltaic and photodetector applications ranging from the visible to near-infrared wavelengths.

  1. Large area Germanium Tin nanometer optical film coatings on highly flexible aluminum substrates.

    PubMed

    Jin, Lichuan; Zhang, Dainan; Zhang, Huaiwu; Fang, Jue; Liao, Yulong; Zhou, Tingchuan; Liu, Cheng; Zhong, Zhiyong; Harris, Vincent G

    2016-09-26

    Germanium Tin (GeSn) films have drawn great interest for their visible and near-infrared optoelectronics properties. Here, we demonstrate large area Germanium Tin nanometer thin films grown on highly flexible aluminum foil substrates using low-temperature molecular beam epitaxy (MBE). Ultra-thin (10-180 nm) GeSn film-coated aluminum foils display a wide color spectra with an absorption wavelength ranging from 400-1800 nm due to its strong optical interference effect. The light absorption ratio for nanometer GeSn/Al foil heterostructures can be enhanced up to 85%. Moreover, the structure exhibits excellent mechanical flexibility and can be cut or bent into many shapes, which facilitates a wide range of flexible photonics. Micro-Raman studies reveal a large tensile strain change with GeSn thickness, which arises from lattice deformations. In particular, nano-sized Sn-enriched GeSn dots appeared in the GeSn coatings that had a thickness greater than 50 nm, which induced an additional light absorption depression around 13.89 μm wavelength. These findings are promising for practical flexible photovoltaic and photodetector applications ranging from the visible to near-infrared wavelengths.

  2. Contamination of drinking water by coliforms from biofilms grown on rubber-coated valves.

    PubMed

    Kilb, Beate; Lange, Bernd; Schaule, Gabriela; Flemming, Hans-Curt; Wingender, Jost

    2003-10-01

    In water samples from drinking water distribution systems, coliform bacteria (predominantly Citrobacter species) were repeatedly detected. Disinfection and flushing of the systems did not erase the problem. The pattern of the coliform occurrences indicated contamination originating from biofilms. After inspection of internal surfaces of the systems, no significant biofilm growth was observed on pipe surfaces, but in a number of cases, visible biofilms were detected on rubber-coated valves which harboured the same coliform species as those found in the drinking water samples. In these cases, the rubber-coated valves seemed to act as point sources for the contamination of water.

  3. Thermochromic vanadium dioxide smart coatings grown on Kapton substrates by reactive pulsed laser deposition

    SciTech Connect

    Soltani, M.; Chaker, M.; Haddad, E.; Kruzelesky, R. V.

    2006-05-15

    Thermochromic undoped and metal (Ti and W)-doped VO{sub 2} smart coatings were achieved on Kapton HN by reactive pulsed laser deposition. The optimization of the deposition was conducted with Si (100) substrates. The coatings were deposited at relatively low deposition temperatures (250, 300, and 350 deg. C), which are compatible with the characteristics of Kapton. The stoichiometry of the VO{sub 2}-coated Kapton was confirmed by x-ray photoelectron spectroscopy analysis of the vanadium and oxygen bands. Moreover, the single phase VO{sub 2} was confirmed by x-ray diffraction of VO{sub 2}/Si synthesized at 300 deg. C. Unlike VO{sub 2}/Kapton, the VO{sub 2}/Si exhibited the well-known semiconductor-to-metallic transition, as shown by the temperature dependence of the infrared transmittance. This coating exhibited a similar transition temperature to that of VO{sub 2} single crystal ({approx_equal}68 deg. C), but a small transmittance switching (about 7%) at 2.5 {mu}m. The temperature dependence of the electrical resistivity of all coatings on Kapton was investigated by means of the standard four-point probe technique. The resistivity decreased with increasing temperature. No abrupt semiconductor-to-metallic transition was observed either for undoped or for metal-doped VO{sub 2} coatings. It was found that Ti and W dopants have an antagonistic effect on the resistivity. The resistivity was enhanced by the Ti dopant, whereas it was decreased for W-doped VO{sub 2} coatings. These results show that the tunability of the resistivity can be tailored either by controlling the deposition temperature or by adjusting the concentration of Ti and W dopants. In addition, at room temperature a much higher temperature coefficient of resistance of -3.29%/ deg. C was achieved in W(0.5%)-doped VO{sub 2}/Kapton. Finally, these VO{sub 2} smart coatings are promising materials for the IR sensing and sunshield applications.

  4. Optical and electrical properties of Titania thin films doped with In3+ and grown by sol-gel process.

    NASA Astrophysics Data System (ADS)

    Rodolfo Palomino Merino, Martín; Lozada Morales, Rosendo; Xoxocotzi Aguilar, Reyna; Díaz Furlong, Alfonso

    2004-03-01

    Using the sol-gel process were prepared Titania (TiO2) thin films formed on glass substrates by dip-coating method. The samples were grown starting from Titanium Isopropoxide and changing the concentration of In3+ ions from Indium Nitrate. The results of the characterization of the samples by UV-VIS spectroscopy , IR , thermopotency and conductivity will be reported.

  5. Fundamental optical properties of InN grown by epitaxial lateral overgrowth method

    SciTech Connect

    Kametani, Tatsuma; Kamimura, Jumpei; Inose, Yuta; Kunugita, Hideyuki; Kikuchi, Akihiko; Kishino, Katsumi; Ema, Kazuhiro

    2013-12-04

    Optical properties of InN grown by the epitaxial lateral overgrowth (ELO) method have been studied using photoluminescence (PL) and excitation-correlation (EC) measurements. The PL spectrum is analyzed by free-electron recombination band (FERB) model, which shows that the ELO sample has a very low background carrier concentration (n=5.5*10{sup 16}[cm{sup −3]}). EC measurements show that the dependences of the band gap renormalization and Auger effect on the carrier concentrations are similar in spite of the different physical origins.

  6. Optical Properties of a Quantum Dot-Ring System Grown Using Droplet Epitaxy.

    PubMed

    Linares-García, Gabriel; Meza-Montes, Lilia; Stinaff, Eric; Alsolamy, S M; Ware, M E; Mazur, Y I; Wang, Z M; Lee, Jihoon; Salamo, G J

    2016-12-01

    Electronic and optical properties of InAs/GaAs nanostructures grown by the droplet epitaxy method are studied. Carrier states were determined by k · p theory including effects of strain and In gradient concentration for a model geometry. Wavefunctions are highly localized in the dots. Coulomb and exchange interactions are studied and we found the system is in the strong confinement regime. Microphotoluminescence spectra and lifetimes were calculated and compared with measurements performed on a set of quantum rings in a single sample. Some features of spectra are in good agreement.

  7. Structural and optical investigations on seed layer assisted hydrothermally grown ZnO nanorods on flat and textured substrates

    NASA Astrophysics Data System (ADS)

    Rayerfrancis, Arokiyadoss; Balaji Bhargav, P.; Ahmed, Nafis; Balaji, C.; Dhara, Sandip

    2016-12-01

    In this article we report the synthesis of vertically aligned ZnO nanorods on plain as well as textured fluorine doped tin oxide (FTO) coated glass substrate using hydrothermal method. Prior to hydrothermal method, AZO seed layer of thickness 5, 10 and 15 nm were deposited on the chosen substrates by DC magnetron sputtering. The as-grown nanorods were annealed at 450 °C for 3 h to improve the crystallinity. Morphology and structure of the nanorods was observed by field emission scanning electron microscopy. The formation of wurtzite structure was confirmed through x-ray diffraction studies. The optical mode of ZnO, E2 (high) at 434 cm-1 present in the samples was confirmed by Raman spectroscopy. The seed layer assisted growth of ZnO nanorods were defect free, which is confirmed from the photoluminescence spectra, and the intensity of band to band emission is much greater than the emission from the defects at the deep level.

  8. Infrared optical coatings for the EarthCARE Multispectral Imager.

    PubMed

    Hawkins, Gary; Woods, David; Sherwood, Richard; Djotni, Karim

    2014-10-20

    The Earth Cloud, Aerosol and Radiation Explorer mission (EarthCARE) Multispectral Imager (MSI) is a radiometric instrument designed to provide the imaging of the atmospheric cloud cover and the cloud top surface temperature from a sun-synchronous low Earth orbit. The MSI forms part of a suite of four instruments destined to support the European Space Agency Living Planet mission on-board the EarthCARE satellite payload to be launched in 2016, whose synergy will be used to construct three-dimensional scenes, textures, and temperatures of atmospheric clouds and aerosols. The MSI instrument contains seven channels: four solar channels to measure visible and short-wave infrared wavelengths, and three channels to measure infrared thermal emission. In this paper, we describe the optical layout of the infrared instrument channels, thin-film multilayer designs, the coating deposition method, and the spectral system throughput for the bandpass interference filters, dichroic beam splitters, lenses, and mirror coatings to discriminate wavelengths at 8.8, 10.8, and 12.0 μm. The rationale for the selection of thin-film materials, spectral measurement technique, and environmental testing performance are also presented.

  9. Oriented ZnO nanorods grown on a porous polyaniline film as a novel coating for solid-phase microextraction.

    PubMed

    Zeng, Jingbin; Zhao, Cuiying; Chong, Fayun; Cao, Yingying; Subhan, Fazle; Wang, Qianru; Yu, Jianfeng; Zhang, Maosheng; Luo, Liwen; Ren, Wei; Chen, Xi; Yan, Zifeng

    2013-12-06

    In this work, oriented ZnO nanorods (ZNRs) were in situ hydrothermally grown on a porous polyaniline (PANI) film to function as a solid-phase microextraction (SPME) coating. Scanning electron microscopy (SEM) study revealed that the majority of oriented ZNRs grew from pores of PANI matrix, which protected the ZNRs from easily peeling off during operation. Furthermore, in this process, a thin layer of PANI was found to cover the ZNRs, which can enlarge the effective surface area of the composite coating. This ZNRs/PANI composite coating combined the merits of both ZNRs and PANI and, thus, has several advantages over that of sole PANI film and ZNRs coating such as improved extraction efficiency for benzene homologues, enhanced mechanical stability and longer service life (over 150 cycles of SPME-GC operation). Coupled with gas chromatography-flame ionization detector (GC-FID), the optimized SPME-GC-FID method was used for the analysis of six benzene homologues in water samples. The calibration curves were linear from 1 to 1000μgL(-1) for each analyte, and the limits of detection were between 0.001 and 0.024μgL(-1). Single fiber repeatability and fiber-to-fiber reproducibility were in the range of 1.3-6.8% and 5.3-11.2%, respectively. The spiked recoveries at 100 and 5μgL(-1) for three environmental water samples were in the range of 79.8-115.4% and 73.7-117.4%, respectively.

  10. Nonlinear optical properties of molecular beam epitaxy grown Bi1 - xSbx

    NASA Astrophysics Data System (ADS)

    Youngdale, E. R.; Meyer, J. R.; Hoffman, C. A.; Bartoli, F. J.; Partin, D. L.; Thrush, C. M.; Heremans, J. P.

    1990-07-01

    We discuss the first investigation of Bi1-xSbx as an infrared nonlinear optical material. Nondegenerate four-wave mixing experiments at CO2 laser wavelengths yield a large nonlinearity (χ(3)≊3×10-4 esu) which does not saturate at power densities up to 0.5 MW/cm2. Both the ambient and substrate interfaces of the film are highly reflective and the étalon they form is found to have a large effect on the transmission and reflectivity spectra of the as-grown films. This suggests the possibility that constructive interference of the film's internal optical fields could be used to considerably enhance the nonlinear signal.

  11. Hybrid glass coatings for optical fibers: effect of coating thickness on strength and dynamic fatigue characteristics of silica fibers

    NASA Astrophysics Data System (ADS)

    Wojcik, A. B.; Matthewson, M. J.; Castelino, K. T.; Wojcik, J.; Walewski, A.

    2006-04-01

    Specialty optical fibers operating in harsh aerospace environments are typically exposed to high temperatures and elevated humidity. This calls for better performing protective coatings. Recently developed sol-gel derived inorganicorganic hybrid materials called hybrid glass offered improved protective performance as compared to standard dual polymer coated fibers [1]. In this paper we examine the effectiveness of online UV curing for the protective ability of hybrid glass coatings. For this purpose two types of UV-curable hybrid glass candidates representing two different concentrations of acrylate groups were applied online to silica fibers as single and dual coats. Samples of fibers were collected and subjected to dynamic fatigue testing by two-point bending. The stress corrosion parameter, n, as well as the strength of the fibers were determined. Both the strength and n were higher for fibers with two layers of coating as compared to single coatings even when the thickness of both one and two layer coatings was the same. This may be caused by the greater degree of cross linking of the inorganic component when the coating is exposed twice to the heat generated in the UV chamber. Coating materials with reduced acrylate group content had higher values of the fatigue parameter n but at the same time reduced strength.

  12. Correlation of Predicted and Observed Optical Properties of Multilayer Thermal Control Coatings

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.

    1998-01-01

    Thermal control coatings on spacecraft will be increasingly important, as spacecraft grow smaller and more compact. New thermal control coatings will be needed to meet the demanding requirements of next generation spacecraft. Computer programs are now available to design optical coatings and one such program was used to design several thermal control coatings consisting of alternating layers of WO3 and SiO2. The coatings were subsequently manufactured with electron beam evaporation and characterized with both optical and thermal techniques. Optical data were collected in both the visible region of the spectrum and the infrared. Predictions of solar absorptance and infrared emittance were successfully correlated to the observed thermal control properties. Functional performance of the coatings was verified in a bench top thermal vacuum chamber.

  13. Optical fiber refractometers based on indium tin oxide coatings fabricated by sputtering.

    PubMed

    Lopez, S; del Villar, I; Ruiz Zamarreño, C; Hernaez, M; Arregui, F J; Matias, I R

    2012-01-01

    This Letter presents the fabrication of optical fiber refractometers based on indium tin oxide (ITO) coatings deposited by sputtering with response in the visible region. ITO thin films have been sputtered by means of a rotating mechanism that enables the fabrication of smooth and homogeneous coatings onto the optical fiber core. The ITO coating acts as a resonance supporting layer. This permits us to couple light from the waveguide to the ITO-coating/external medium region at specific wavelength ranges. The device is sensitive to external medium refractive index, which allows its utilization as a refractometer. The sensitivity is dependent on the coating thickness, ranging from 523.21 to 1221 nm/refractive index unit in the explored sensors. The sensor development process is time effective compared to other techniques such as dip coating or layer-by-layer self-assembly, which is interesting in terms of mass production. © 2012 Optical Society of America

  14. Enhanced osteogenesis on titanium implants by UVB photofunctionalization of hydrothermally grown TiO₂ coatings.

    PubMed

    Lorenzetti, Martina; Dakischew, Olga; Trinkaus, Katja; Lips, Katrin Susanne; Schnettler, Reinhard; Kobe, Spomenka; Novak, Saša

    2015-07-01

    Even though Ti-based implants are the most used materials for hard tissue replacement, they may present lack of osseointegration on the long term, due to their inertness. Hydrothermal treatment (HT) is a useful technique for the synthesis of firmly attached, highly crystalline coatings made of anatase titanium dioxide (TiO2), providing favorable nanoroughness and higher exposed surface area, as well as greater hydrophilicity, compared to the native amorphous oxide on pristine titanium. The hydrophilicity drops even more by photofunctionalization of the nanostructured TiO2-anatase coatings under UV light. Human mesenchymal stem cells exhibited a good response to the combination of the positive surface characteristics, especially in respect to the UVB pre-irradiation. The results showed that the cells were not harmed in terms of viability; even more, they were encouraged to differentiate in osteoblasts and to become osteogenically active, as confirmed by the calcium ion uptake and the formation of well-mineralized, bone-like nodule structures. In addition, the enrichment of hydroxyl groups on the HT-surfaces by UVB photofunctionalization accelerated the cell differentiation process and greatly improved the osteogenesis in comparison with the nonirradiated samples. The optimal surface characteristics of the HT-anatase coatings as well as the high potentiality of the photo-induced hydrophilicity, which was reached during a relatively short pre-irradiation time (5 h) with UVB light, can be correlated with better osseointegration ability in vivo; among the samples, the superior biological behavior of the roughest and most hydrophilic HT coating makes it a good candidate for further studies and applications. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  15. Post-annealing effect on optical absorbance of hydrothermally grown zinc oxide nanorods

    SciTech Connect

    Mohar, Rahmat Setiawan; Djuhana, Dede; Imawan, Cuk; Harmoko, Adhi; Fauzia, Vivi; Iwan, S.

    2016-04-19

    In this study, the optical absorbance of zinc oxide (ZnO) nanorods was investigated. The ZnO thin film were deposited on indium tin oxide (ITO) layers using ultrasonic spray pyrolysis (USP) method and then grown by hydrothermal method. In order to improve the optical absorbance, the ZnO nanorods were then post-annealed for one hour at three different of temperatures, namely 250, 400, and 500 °C. The X-ray diffraction (XRD) spectra and FESEM images show that the ZnO nanorods have the hexagonal wurtzite crystal structure and the increasing of post-annealing temperature resulted in the increasing of crystallite size from 38.2 nm to 48.4 nm. The UV-vis spectra shows that all samples of ZnO nanorods exhibited the identical sharp absorption edge at 390 nm indicating that all samples have the same bandgap. The post-annealing process seemed to decrease the optical absorbance in the region of 300-550 nm and increase the optical absorbance in the region of 550-700 nm..

  16. Growth-induced optical anisotropy of epitaxial garnet films grown on (110)-oriented substrates

    NASA Astrophysics Data System (ADS)

    Kitamura, K.; Iyi, N.; Kimura, S.; Chevrier, F.; Devignes, J. M.; Le Gall, H.

    1986-08-01

    Garnet films of nominal composition (Y,Nd)3Ga5O12, were grown on (110) 1°-off Gd3Ga5O12 substrates for investigation of their growth-induced optical anisotropy. Optical birefringence and directions of the electric vectors of polarized rays passing through the films were measured under a polarizing microscope using a Brace-Köhler compensator. The growth-induced anisotropy of these films optically exhibited orthorhombic characteristics with the X, Y, and Z optic elasticity axes coinciding with the [001], [110], and [1¯10] directions, respectively. The crystallographic data obtained by means of single-crystal diffractometry suggested that the cubic crystal system of the garnet film was distorted, though very slightly, to an orthorhombic one with a,b, and c axes that coincided, respectively, with the [1¯10],[001], and [110] of the original cubic cell. In addition, by annealing at 1150 °C, this distortion disappeared and the crystal system reverted to cubic.

  17. Optical excitation of Er centers in GaN epilayers grown by MOCVD

    NASA Astrophysics Data System (ADS)

    George, D. K.; Hawkins, M. D.; Jiang, H. X.; Lin, J. Y.; Zavada, J. M.; Vinh, N. Q.

    2016-02-01

    In this paper we present results of photoluminescence (PL), photoluminescence excitation (PLE), and time resolved PL spectroscopy of the 4I13/2 → 4I15/2 transition in Er optical centers in GaN epilayers grown by metal-organic chemical vapor deposition. Under resonance excitation via the higher-lying inner 4f shell transitions and band-to-band excitation of the semiconductor host, the PL and PLE spectra reveal an existence of two types of Er optical centers from isolated and the defect-related Er centers in GaN epilayers. These centers have different PL spectra, local defect environments, decay dynamics, and excitation cross-sections. The isolated Er optical center, which can be excited by either excitation mechanism, has the same decay dynamics, but possesses a much higher cross-section under band-to-band excitation. In contrast, the defect-related Er center can only be observed through band-to-band excitation but has the largest crosssection. Our results indicate pathways for efficient optical excitation of Er-doped GaN semiconductors.

  18. Improved antireflection coated microspheres for biological applications of optical tweezers

    NASA Astrophysics Data System (ADS)

    Ferro, Valentina; Sonnberger, Aaron; Abdosamadi, Mohammad K.; McDonald, Craig; Schäffer, Erik; McGloin, David

    2016-09-01

    The success of optical tweezers in cellular biology1 is in part due to the wide range of forces that can be applied, from femto- to hundreds of pico-Newtons; nevertheless extending the range of applicable forces to the nanoNewton regime opens access to a new set of phenomena that currently lie beyond optical manipulation. A successful approach to overcome the conventional limits on trapping forces involves the optimization of the trapped probes. Jannasch et al.2 demonstrated that an anti-reflective shell of nanoporous titanium dioxide (aTiO2, nshell = 1.75) on a core particle made out of titanium dioxide in the anatase phase (cTiO2, ncore = 2.3) results in trappable microspheres capable to reach forces above 1 nN. Here we present how the technique can be further improved by coating the high refractive index microspheres with an additional anti-reflective shell made out of silica (SiO2). This external shell not only improves the trap stability for microspheres of different sizes, but also enables the use of functionalization techniques already established for commercial silica beads in biological experiments. We are also investigating the use of these new microspheres as probes to measure adhesion forces between intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 1 (LFA-1) in effector T-Cells and will present preliminary results comparing standard and high-index beads.

  19. Effect of coating on the strain transfer of optical fiber sensors.

    PubMed

    Her, Shiuh-Chuan; Huang, Chih-Ying

    2011-01-01

    Optical fiber strain sensors with light weight, small dimensions and immunity to electromagnetic interference are widely used in structural health monitoring devices. As a sensor, it is expected that the strains between the optical fiber and host structure are the same. However, due to the shear deformation of the protective coating, the optical fiber strain is different from that of host structure. To improve the measurement accuracy, the strain measured by the optical fiber needs to be modified to reflect the influence of the coating. In this investigation, a theoretical model of the strain transferred from the host material to the optical fiber is developed to evaluate the interaction between the host material and coating. The theoretical predictions are validated with a numerical analysis using the finite element method. Experimental tests are performed to reveal the differential strains between the optical fiber strain sensor and test specimen. The Mach-Zehnder interferometric type fiber-optic sensor is adopted to measure the strain. Experimental results show that the strain measured at the optical fiber is lower than the true strain in the test specimen. The percentage of strain in the test specimen actually transferred to the optical fiber is dependent on the bonded length of the optical fiber and the protective coating. The general trend of the strain transformation obtained from both experimental tests and theoretical predictions shows that the longer the bonded length and the stiffer the coating the more strain is transferred to the optical fiber.

  20. Process for producing a well-adhered durable optical coating on an optical plastic substrate. [abrasion resistant polymethyl methacrylate lenses

    NASA Technical Reports Server (NTRS)

    Kubacki, R. M. (Inventor)

    1978-01-01

    A low temperature plasma polymerization process is described for applying an optical plastic substrate, such as a polymethyl methacrylate lens, with a single layer abrasive resistant coating to improve the durability of the plastic.

  1. Optical property degradation of anodic coatings in the Space Station low earth orbit

    NASA Technical Reports Server (NTRS)

    David, Kaia E.; Babel, Hank W.

    1992-01-01

    The anodic coatings and optical properties to be used for passive thermal control of the SSF are studied. Particular attention is given to the beginning-of-life optical properties for aluminum alloys suitable for structural and radiator applications, the statistical variation in the beginning-of-life properties, and estimates of the end-of-life properties of the alloys based on ultraviolet radiation testing and flight test results. It is concluded that anodic coatings can be used for thermal control of long life, low earth orbit spacecraft. Some use restrictions are defined for specific cases. Anodic coatings have been selected as baseline thermal control coating for large portions of the SSF.

  2. Optical property degradation of anodic coatings in the Space Station low earth orbit

    NASA Technical Reports Server (NTRS)

    David, Kaia E.; Babel, Hank W.

    1992-01-01

    The anodic coatings and optical properties to be used for passive thermal control of the SSF are studied. Particular attention is given to the beginning-of-life optical properties for aluminum alloys suitable for structural and radiator applications, the statistical variation in the beginning-of-life properties, and estimates of the end-of-life properties of the alloys based on ultraviolet radiation testing and flight test results. It is concluded that anodic coatings can be used for thermal control of long life, low earth orbit spacecraft. Some use restrictions are defined for specific cases. Anodic coatings have been selected as baseline thermal control coating for large portions of the SSF.

  3. Radiation damages to amorphous-carbon optical coatings

    NASA Astrophysics Data System (ADS)

    Juha, L.; Bittner, M.; De Grazia, M.; Feldhaus, J.; Gaudin, J.; Guizard, S.; Jacobi, S.; Kozlova, M.; Krasa, J.; Krzywinski, J.; Merdji, H.; Michaelsen, C.; Mocek, T.; Nietubyc, R.; Jurek, M.; Polan, J.; Prag, A. R.; Rus, B.; Sobierajski, R.; Steeg-Keitel, B.; Stoermer, M.; Stupka, M.; Vorlicek, V.; Wiesmann, J.; Wild, J.

    2005-08-01

    The multi-mJ, 21-nm soft-x-ray laser at the PALS facility was focused on the surface of amorphous carbon (a-C) coating, developed for heavily loaded XUV/x-ray optical elements. AFM (Atomic Force Microscopy) images show 3-micrometer expansion of the irradiated material. Raman spectra, measured with an Ar+ laser microbeam in both irradiated and unirradiated areas, confirm a high degree of graphitization in the irradiated layer. In addition to this highfluence (~ 1 J/cm2), single-shot experiment, it was necessary to carry out an experiment to investigate consequences of prolonged XUV irradiation at relatively low fluence. High-order harmonic (HH) beam generated at the LUCA facility in CEA/Saclay Research Center was used as a source of short-wavelength radiation delivering high-energy photons on the surface at a low single-shot fluence but with high-average power. a-C irradiated at a low fluence, i.e., < 0.1 mJ/cm2 by many HH shots exhibits an expansion for several nanometers. Although it is less dramatic change of surface morphology than that due to single-hot x-ray-laser exposure even the observed nanometer-sized changes caused by the HH beam on a-C surface could influence reflectivity of a grazing incidence optical element. These results seem to be important for estimating damages to the surfaces of highly irradiated optical elements developed for guiding and focusing the ultraintense XUV/x-ray beams provided by new generation sources (i.e., VUV FEL and XFEL in Hamburg; LCLS in Stanford) because, up to now, only melting and vaporization, but not graphitization, have been taken into account.

  4. Atom probe tomography of a Ti-Si-Al-C-N coating grown on a cemented carbide substrate.

    PubMed

    Thuvander, M; Östberg, G; Ahlgren, M; Falk, L K L

    2015-12-01

    The elemental distribution within a Ti-Si-Al-C-N coating grown by physical vapour deposition on a Cr-doped WC-Co cemented carbide substrate has been investigated by atom probe tomography. Special attention was paid to the coating/substrate interface region. The results indicated a diffusion of substrate binder phase elements into the Ti-N adhesion layer. The composition of this layer, and the Ti-Al-N interlayer present between the adhesion layer and the main Ti-Si-Al-C-N layer, appeared to be sub-stoichiometric. The analysis of the interlayer showed the presence of internal surfaces, possibly grain boundaries, depleted in Al. The composition of the main Ti-Al-Si-C-N layer varied periodically in the growth direction; layers enriched in Ti appeared with a periodicity of around 30 nm. Laser pulsing resulted in a good mass resolution that made it possible to distinguish between N(+) and Si(2+) at 14 Da. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Optical properties of nanostructured TiO2 thin films and their application as antireflection coatings on infrared detectors.

    PubMed

    Jayasinghe, R C; Perera, A G U; Zhu, H; Zhao, Y

    2012-10-15

    Oblique-angle deposited titanium dioxide (TiO(2)) nanorods have attracted much attention as good antireflection (AR) coating material due to their low n profile. Therefore, it is necessary to better understand the optical properties of these nanorods. TiO(2) nanorods grown on glass and Si substrates were characterized in the visible (0.4-0.8 μm) and infrared (2-12 μm) regions to extract their complex n profiles empirically. Application of these nanorods in multilayer AR coatings on infrared detectors is also discussed. Optimization of graded index profile of these AR coatings in the broad infrared region (2-12 μm) even at oblique angles of incidence is discussed. The effective coupling between the incoming light and multiple nanorod layers for reducing the reflection is obtained by optimizing the effect from Fabry-Perot oscillations. An optimized five-layer AR coating on GaN shows the reflectance less than 3.3% for normal incidence and 10.5% at 60° across the whole 2-8 μm spectral range.

  6. Geometrical characteristics and damage morphology of nodules grown from artificial seeds in multilayer coating.

    PubMed

    Shan, Yongguang; He, Hongbo; Wei, Chaoyang; Li, Shuhong; Zhou, Ming; Li, Dawei; Zhao, Yuan'an

    2010-08-01

    Nodules have been planted in an HfO(2)/SiO(2) multilayer system with absorptive gold nanoparticle seeds located on the surface of a substrate. The topography of nodules was scanned by an atomic force microscope and imaged by a scanning electron microscope. The underlying characteristics of nodules were revealed by a focused ion beam. The cross-sectional profiles reveal that nodules grown from small seeds have a continuous boundary and better mechanical stability. A laser-induced damage test shows that nodules decrease the laser-induced damage threshold by up to 3 times. The damage pits are exclusively caused by nodular ejection and triggered by the absorptive seeds. The distribution of electric field and average temperature rise in the nodules were analyzed. Theoretical results met experimental results very well. The strong absorptive seed and microlens effect of the nodule play important roles in laser-induced damage of a planted nodule.

  7. High-temperature sapphire optical sensor fiber coatings

    NASA Astrophysics Data System (ADS)

    Desu, Seshu B.; Claus, Richard O.; Raheem, Ruby; Murphy, Kent A.

    1990-10-01

    the filter. These modes may be attributed to a number of material degradation mechanisms, such as thermal shock, oxidation corrosion of the material, mechanical loads, or phase changes in the filter material. Development of high temperature optical fiber (sapphire) sensors embedded in the CXF filters would be very valuable for both monitoring the integrity of the filter during its use and understanding the mechanisms of degradation such that durable filter development will be facilitated. Since the filter operating environment is very harsh, the high temperature sapphire optical fibers need to be protected and for some sensing techniques the fiber must also be coated with low refractive index film (cladding). The objective of the present study is to identify materials and develop process technologies for the application of claddings and protective coatings that are stable and compatible with sapphire fibers at both high temperatures and pressures.

  8. Parasitic oscillation suppression in solid state lasers using optical coatings

    DOEpatents

    Honea, Eric C.; Beach, Raymond J.

    2005-06-07

    A laser gain medium having a layered coating on at least certain surfaces of the laser gain medium. The layered coating having a reflective inner material and an absorptive scattering outside material.

  9. Comparison of the optical characteristics of GaAs photocathodes grown using MBE and MOCVD

    NASA Astrophysics Data System (ADS)

    Bourree, Loig E.; Chasse, David R.; Thamban, P. L. Stephan; Glosser, Robert

    2003-02-01

    Modern image tube intensifier photocathodes rely on a GaAs active layer, which has traditionally been grown using metallorganic chemical vapor deposition (MOCVD) due to its high throughput and lower cost of operation. Molecular beam epitaxy (MBE) processes have not been thoroughly investigated in that context. The latter technique demonstrates greater structural interface control as well as an improved growth quality for a multitude of applications. Still, at this point it is uncertain, considering actual fabrication techniques for image intensifiers, that the higher growth quality will result in an improvement of devices. Studies are being carried out to compare fundamental optical parameters between GaAs photocathodes grown by both MOCVD and MBE following the same growth and fabrication guidelines. These experiments involve using photoluminescence and Raman spectroscopy to obtain electron and phonon energy information on the materials. An atomic force microscope (AFM) is employed to compare the surface roughness of both methods. In addition, the white light responses of the photocathodes are also evaluated during the creation of a negative electron affinity (NEA) surface to observe any differences between the two growth techniques.

  10. Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.

    1975-01-01

    The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

  11. Characterisation of coated aerosols using optical tweezers and neutron reflectometry

    NASA Astrophysics Data System (ADS)

    Jones, S. H.; Ward, A.; King, M. D.

    2013-12-01

    Thin organic films are believed to form naturally on the surface of aerosols [1,2] and influence aerosol properties. Cloud condensation nuclei formation and chemical reactions such as aerosol oxidation are effected by the presence of thin films [3]. There is a requirement to characterise the physical properties of both the core aerosol and its organic film in order to fully understand the contribution of coated aerosols to the indirect effect. Two complementary techniques have been used to study the oxidation of thin organic films on the surface of aerosols; laser optical tweezers and neutron reflectometry. Micron sized polystyrene beads coated in oleic acid have been trapped in air using two counter propagating laser beams. Polystyrene beads are used as a proxy for solid aerosol. The trapped aerosol is illuminated with a white LED over a broadband wavelength range and the scattered light collected to produce a Mie spectrum [4]. Analysis of the Mie spectrum results in determination of the core polystyrene bead radius, the oleic acid film thickness and refractive index dispersion of the core and shell [5]. A flow of ozone gas can then be introduced into the aerosol environment to oxidise the thin film of oleic acid and the reaction followed by monitoring the changes in the Mie spectrum. The results demonstrate complete removal of the oleic acid film. We conclude that the use of a counter propagating optical trap combined with white light Mie spectroscopy can be used to study a range of organic films on different types of aerosols and their oxidation reactions. Neutron reflectometry has been used as a complementary technique to study the oxidation of monolayer films at the air-water interface in order to gain information on reaction kinetics. The oxidation of an oleic acid film at the air-water interface by the common tropospheric oxidant ozone has been studied using a Langmuir trough. Results indicate complete removal of the oleic acid film with ozone in agreement

  12. Optical properties of InP doping superlattices grown by metal organic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Gal, M.; Viner, J. M.; Taylor, P. C.; Yaun, J. S.; Stringfellow, G. B.

    1987-04-01

    Photoluminescence (PL), time-resolved PL, and photoreflectance spectroscopy are applied to InP doping superlattices grown by metal organic chemical vapor deposition. It is observed that the emission peak and line shape depend on the optical excitation intensity; the peak of the CW PL spectrum increases in energy with the intensity of the pumping light; the highest energy peak is at 888 nm; and the time-resolved PL exhibits long decay times. The energy separation of the quantized subbands is studied by measuring the PR spectra of two samples. The measurements reveal that PR line shapes are explained by photomodulation of the subbands in the conduction band; these line shapes account for the dependence of the spectrum on the power of the exciting light and on the layer thickness.

  13. Optical properties of single wurtzite/zinc-blende ZnSe nanowires grown at low temperature

    SciTech Connect

    Zannier, V.; Cremel, T.; Kheng, K.; Artioli, A.; Ferrand, D.; Grillo, V.

    2015-09-07

    ZnSe nanowires with a dominant wurtzite structure have been grown at low temperature (300 °C) by molecular beam epitaxy assisted by solid Au nanoparticles. The nanowires emission is polarized perpendicularly to their axis in agreement with the wurtzite selection rules. Alternations of wurtzite and zinc-blende regions have been observed by transmission electron microscopy, and their impact on the nanowires optical properties has been studied by microphotoluminescence. The nanowires show a dominant intense near-band-edge emission as well as the ZnSe wurtzite free exciton line. A type II band alignment between zinc-blende and wurtzite ZnSe is evidenced by time-resolved photoluminescence. From this measurement, we deduce values for the conduction and valence band offsets of 98 and 50 meV, respectively.

  14. 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

  15. Optical and structural characterisation of epitaxial nanoporous GaN grown by CVD.

    PubMed

    Mena, Josué; Carvajal, Joan J; Martínez, Oscar; Jiménez, Juan; Zubialevich, Vitaly Z; Parbrook, Peter J; Diaz, Francesc; Aguiló, Magdalena

    2017-09-15

    In this paper we study the optical properties of nanoporous gallium nitride (GaN) epitaxial layers grown by chemical vapour deposition on non-porous GaN substrates, using photoluminescence, cathodoluminescence, and resonant Raman scattering, and correlate them with the structural characteristic of these films. We pay special attention to the analysis of the residual strain of the layers and the influence of the porosity in the light extraction. The nanoporous GaN epitaxial layers are under tensile strain, although the strain is progressively reduced as the deposition time and the thickness of the porous layer increases, becoming nearly strain free for a thickness of 1.7 μm. The analysis of the experimental data point to the existence of vacancy complexes as the main source of the tensile strain.

  16. Optical Properties of ZnO Soccer-Ball Structures Grown by Vapor Phase Transport

    NASA Astrophysics Data System (ADS)

    Nam, Giwoong; Lee, Sang-heon; Kim, Soaram; Kim, Min Su; Kim, Do Yeob; Gug Yim, Kwang; Lee, Dong-Yul; Kim, Jin Soo; Kim, Jong Su; Son, Jeong-Sik; Kim, Sung-O.; Jung, Jae Hak; Leem, Jae-Young

    2012-02-01

    ZnO soccer balls were grown on an Au-catalyzed Si(100) substrate by vapor phase transport (VPT) with a mixture of zinc oxide and graphite powders. Temperature-dependent PL was carried out to investigate the mechanism governing the quenching behavior of the PL spectra. From the PL spectra of the ZnO soccer balls at 10 K, several PL peaks were observed at 3.365, 3.318, 3.249, and 3.183 eV corresponding to excitons bound to neutral donors (DoX), a donor-acceptor pair (DAP), first-order longitudinal optical phonon replica of donor-acceptor pair (DAP-1LO), and DAP-2LO, respectively. The mixed system composed of the free exciton (FX) and DoX and the DAP radiative lifetimes were estimated with a theoretical relation between the lifetime and the spectral width. The exciton radiative lifetimes were observed to increase linearly with temperature.

  17. Structural and optical characterizations of InPBi thin films grown by molecular beam epitaxy.

    PubMed

    Gu, Yi; Wang, Kai; Zhou, Haifei; Li, Yaoyao; Cao, Chunfang; Zhang, Liyao; Zhang, Yonggang; Gong, Qian; Wang, Shumin

    2014-01-13

    InPBi thin films have been grown on InP by gas source molecular beam epitaxy. A maximum Bi composition of 2.4% is determined by Rutherford backscattering spectrometry. X-ray diffraction measurements show good structural quality for Bi composition up to 1.4% and a partially relaxed structure for higher Bi contents. The bandgap was measured by optical absorption, and the bandgap reduction caused by the Bi incorporation was estimated to be about 56 meV/Bi%. Strong and broad photoluminescence signals were observed at room temperature for samples with xBi < 2.4%. The PL peak position varies from 1.4 to 1.9 μm, far below the measured InPBi bandgap.

  18. Optical band gap of BiFeO{sub 3} grown by molecular-beam epitaxy

    SciTech Connect

    Ihlefeld, J. F.; Podraza, N. J.; Liu, Z. K.; Schlom, D. G.; Rai, R. C.; Xu, X.; Musfeldt, J. L.; Heeg, T.; Schubert, J.; Chen, Y. B.; Pan, X. Q.; Li, J.; Collins, R. W.; Ramesh, R.

    2008-04-07

    BiFeO{sub 3} thin films have been deposited on (001) SrTiO{sub 3} substrates by adsorption-controlled reactive molecular-beam epitaxy. For a given bismuth overpressure and oxygen activity, single-phase BiFeO{sub 3} films can be grown over a range of deposition temperatures in accordance with thermodynamic calculations. Four-circle x-ray diffraction reveals phase-pure, epitaxial films with {omega} rocking curve full width at half maximum values as narrow as 29 arc sec (0.008 deg.). Multiple-angle spectroscopic ellipsometry reveals a direct optical band gap at 2.74 eV for stoichiometric as well as 5% bismuth-deficient single-phase BiFeO{sub 3} films.

  19. Optical and structural characterisation of epitaxial nanoporous GaN grown by CVD

    NASA Astrophysics Data System (ADS)

    Mena, Josué; Carvajal, Joan J.; Martínez, Oscar; Jiménez, Juan; Zubialevich, Vitaly Z.; Parbrook, Peter J.; Diaz, Francesc; Aguiló, Magdalena

    2017-09-01

    In this paper we study the optical properties of nanoporous gallium nitride (GaN) epitaxial layers grown by chemical vapour deposition on non-porous GaN substrates, using photoluminescence, cathodoluminescence, and resonant Raman scattering, and correlate them with the structural characteristic of these films. We pay special attention to the analysis of the residual strain of the layers and the influence of the porosity in the light extraction. The nanoporous GaN epitaxial layers are under tensile strain, although the strain is progressively reduced as the deposition time and the thickness of the porous layer increases, becoming nearly strain free for a thickness of 1.7 μm. The analysis of the experimental data point to the existence of vacancy complexes as the main source of the tensile strain.

  20. 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.

  1. Structural and optical characterization and scintillator application of hydrothermal-grown ZnO microrods

    NASA Astrophysics Data System (ADS)

    Empizo, Melvin John F.; Santos-Putungan, Alexandra B.; Yamanoi, Kohei; Salazar, Hernanie T.; Anguluan, Eloise P.; Mori, Kazuyuki; Arita, Ren; Minami, Yuki; Luong, Mui Viet; Shimizu, Toshihiko; Estacio, Elmer S.; Somintac, Armando S.; Salvador, Arnel A.; Sarmago, Roland V.; Fukuda, Tsuguo; Sarukura, Nobuhiko

    2017-03-01

    ZnO microrods are fabricated by a simple hydrothermal growth route using zinc acetate dihydrate [Zn(CH3COO)2·2H2O] and hexamethylenetetramine [(CH2)6N4] aqueous solutions. The as-prepared microrods exhibit uniform dimensions, well-faceted surfaces, and hexagonal crystal structure. The microrods also have an intense ultraviolet (UV) emission at 392 nm with an average lifetime of 80 ps. No peaks are observed at the visible wavelengths that can be attributed to defect-related emissions. With excellent structural and optical properties and with loose adhesion to their substrates, the ZnO microrods can be isolated, harvested, and manipulated and can be integrated as building blocks of a microstructured scintillator screen. The proposed scintillator screen possibly offers efficient and precise detection with high resolution. Hydrothermal-grown ZnO microrods then hold a promise towards radiation detector innovation and integrated optoelectronic microsystems.

  2. Nanoparticle coated optical fibers for single microbubble generation

    NASA Astrophysics Data System (ADS)

    Pimentel-Domínguez, Reinher; Hernández-Cordero, Juan

    2011-09-01

    The study of bubbles and bubbly flows is important in various fields such as physics, chemistry, medicine, geophysics, and even the food industry. A wide variety of mechanical and acoustic techniques have been reported for bubble generation. Although a single bubble may be generated with these techniques, controlling the size and the mean lifetime of the bubble remains a difficult task. Most of the optical methods for generation of microbubbles involve high-power pulsed laser sources focused in absorbing media such as liquids or particle solutions. With these techniques, single micron-sized bubbles can be generated with typical mean lifetimes ranging from nano to microseconds. The main problem with these bubbles is their abrupt implosion: this produces a shock wave that can potentially produce damages on the surroundings. These effects have to be carefully controlled in biological applications and in laser surgery, but thus far, not many options are available to effectively control micron-size bubble growth. In this paper, we present a new technique to generate microbubbles in non-absorbing liquids. In contrast to previous reports, the proposed technique uses low-power and a CW radiation from a laser diode. The laser light is guided through an optical fiber whose output end has been coated with nanostructures. Upon immersing the tip of the fiber in ethanol or water, micron-size bubbles can be readily generated. With this technique, bubble growth can be controlled through adjustments on the laser power. We have obtained micron-sized bubbles with mean lifetimes in the range of seconds. Furthermore, the generated bubbles do not implode, as verified with a high-speed camera and flow visualization techniques.

  3. Repair of a mirror coating on a large optic for high laser-damage applications using ion milling and over-coating methods

    NASA Astrophysics Data System (ADS)

    Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

    2014-10-01

    When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface, and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO2 and SiO2 layers for high reflection at 1054 nm at 45° incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating's high laser-induced damage threshold (LIDT) of 64 J/cm2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49 - 61 J/cm2.

  4. Repair of a mirror coating on a large optic for high laser damage applications using ion milling and over-coating methods

    NASA Astrophysics Data System (ADS)

    Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

    2017-01-01

    When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO2 and SiO2 layers for high reflection at 1054 nm at 45 deg incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating's high laser-induced damage threshold (LIDT) of 64.0 J/cm2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 to 61.0 J/cm2.

  5. Optical investigations on Tb3+ doped L-Histidine hydrochloride mono hydrate single crystals grown by low temperature solution techniques

    NASA Astrophysics Data System (ADS)

    Rajyalakshmi, S.; Ramachandra Rao, K.; Brahmaji, B.; Samatha, K.; Visweswara Rao, T. K.; Bhagavannarayana, G.

    2016-04-01

    The potential nonlinear optical material of Terbium (Tb3+) ion doped L-Histidine hydrochloride monohydrate (LHHC) single crystals were successfully grown. Tb3+:LHHC crystals of 7 mm × 5 mm × 3 mm and 59 mm length and 15 mm diameter have been grown by the slow solvent evaporation and Sankaranarayanan-Ramasamy (SR) techniques respectively. The grown crystals were characterized by single crystal X-ray diffraction analysis to confirm the crystalline structure and morphology. High resolution X-ray diffraction (HRXRD) studies revealed that the SR grown sample shows relatively good crystalline nature with 9″ full-width at half-maximum (FWHM) for the diffraction curve. Functional groups were identified by Fourier transform infra-red spectroscopy (FTIR). The optical transparency and band gaps of grown crystals were measured by UV-Vis spectroscopy. Thermogravimetric and differential thermal analysis (TG/DTA) studies reveal that the crystal was thermally stable up to 155 °C in SR grown crystal. Surface morphology of the growth plane was observed using scanning electron microscopy (SEM). The incorporation of Tb ion was estimated by EDAX. The frequency-dependent dielectric properties of the crystals were carried out for different temperatures. Vickers hardness study carried out on (1 0 0) face at room temperature shows increased hardness of the SR method grown crystal. Second harmonic generation efficiency of SEST and SR grown crystals are 3.2 and 3.5 times greater than that of pure KDP. The Photoluminescence (PL) studies of Tb3+ ions result from the radiative intra-configurational f-f transitions that occur from the 5D4 excited state to the 7Fj (j = 6, 5, 4, 3) ground states. The decay curve of the 5D4 level of emission was observed with a long life time of 319.2041 μs for the SR grown Tb3+:LHHC crystal.

  6. Absorbance Response of Graphene Oxide Coated on Tapered Multimode Optical Fiber Towards Liquid Ethanol

    NASA Astrophysics Data System (ADS)

    Girei, S. H.; Shabaneh, A. A.; Lim, H. M.; Huang, N. H.; Mahdi, M. A.; Yaacob, M. H.

    2015-04-01

    The investigation of graphene oxide (GO) for sensing applications is attractive due to its nanoscale structure and its sensing properties has yet to be fully understood. In this paper, optical response of GO coated optical fiber sensor towards ethanol is described. GO was coated onto a multimode tapered optical fiber by drop-casting technique. The coated fiber was exposed to 5-40% of ethanol in water. The films were characterized with field emission scanning electron microscope, ultraviolet-visible spectroscopy and Raman spectroscopy. The sensing is based on changes following the absorbance of the GO coated optical fiber upon exposure to ethanol. The developed sensor shows fast response and recovery with duration of 22 and 20 s, respectively. The sensor also displays high repeatability and reversibility.

  7. Future trends in optical coatings for high-power laser applications

    SciTech Connect

    Kozlowski, M.R.; Thomas, I.M.

    1994-07-01

    Inertial Confinement Fusion (ICF) research has historically been a driver in the development of high performance, high damage threshold optical coatings. This is particularly the case now as the ICF community develops plans for a proposed 1.8 mega-joule solid state (Nd{sup +3}-phosphate glass) laser system. The new system, the National Ignition Facility, is possible in part due to advances in optical coatings technology including the laser-conditioning of multilayer dielectrics and broadened applications for room-temperature deposited coatings. Sol-gel AR coatings are the standard for large, high-power laser optics and sol-gel HR coatings are being developed. For mirror and polarizer coatings, e-beam-deposited dielectric continue to provide the highest damage threshold coatings, but their laser damage thresholds and optical performance are limited by {mu}m-scale defects and poor control over layer thickness, respectively. More energetic deposition techniques such as IAD and IBS, now popular in the commercial market, offer both advantages and disadvantages in this high-damage-threshold coatings market.

  8. Chemical Silver Coating of Fiber Tips in Near-Field Scanning Optical Microscopy

    NASA Technical Reports Server (NTRS)

    Vikram, Chandra S.; Witherow, William K.

    1998-01-01

    We report what is believed to be the first experimental demonstration of silver coating by a wet chemical process on tapered fiber tips used in near-field scanning optical microscopy. The process is at room temperature and pressure and takes only a few minutes to complete. Many tips can be simultaneously coated.

  9. Development of Multilayer Coatings for Hard X-Ray Optics at NASA Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Gurgew, Danielle N.; Broadway, David M.; Ramsey, Brian; Gregory, Don

    2017-01-01

    Broadband X-ray multilayer coatings are under development at NASA MSFC for use on future astronomical X-ray telescopes. Multilayer coatings deposited onto the reflecting surfaces of X-ray optics can provide a large bandpass enabling observations of higher energy astrophysical objects and phenomena.

  10. Optically and biologically active mussel protein-coated double-walled carbon nanotubes.

    PubMed

    Jung, Yong Chae; Muramatsu, Hiroyuki; Fujisawa, Kazunori; Kim, Jin Hee; Hayashi, Takuya; Kim, Yoong Ahm; Endo, Morinobu; Terrones, Mauricio; Dresselhaus, Mildred S

    2011-12-02

    A method of dispersing strongly bundled double-walled carbon nanotubes (DWNTs) via a homogeneous coating of mussel protein in an aqueous solution is presented. Optical activity, mechanical strength, as well as electrical conductivity coming from the nanotubes and the versatile biological activity from the mussel protein make mussel-coated DWNTs promising as a multifunctional scaffold and for anti-fouling materials.

  11. Fe(C)-coated optical fiber sensors for corrosion alarm monitoring

    NASA Astrophysics Data System (ADS)

    Hu, Wenbin; Gao, Min; Zheng, Xing; Zhu, Cheng; Guo, Donglai; Yang, Minghong

    2015-07-01

    Steel corrosion in concrete leads to severe destructions of the civil engineering structures. The detecting of the early corrosion is especially essential for steel-based structures. This paper summarized a series research works on optical fibre corrosion sensors, based on Fe(C)-coated Fibre Bragg Grating (FBG) and Fe-coated optical fibre polarizer. Three types of optical fibre sensors are presented. Type 1 and type 2, Fe-C coated FBG sensor and Fe coated etched FBG sensor, are both based on Fe(C)-coated FBG. The volume expansion and the RI variation of the coating lead to the FBG central wavelength shift respectively. By monitoring the wavelength shift, the corrosion status is evaluated and monitored. Type 3, Fe-coated optical fibre polarizer, is fabricated by side-polishing a single mode optical fibre and depositing a Fe-film on the polished side-face. The birefringence characteristics of the sensor will be reduced after being corroded, which is used for the corrosion status indicating. The fabrication processes of the three types of sensors are introduced. By investigating the experimental results of corrosion test in NaCl solution, the performance of the sensors are discussed. The experimental results show that the proposed sensors are proved to be sensible of early corrosion.

  12. Low temperature-grown GaAs carrier lifetime evaluation by double optical pump terahertz time-domain emission spectroscopy.

    PubMed

    Mag-Usara, Valynn Katrine; Funkner, Stefan; Niehues, Gudrun; Prieto, Elizabeth Ann; Balgos, Maria Herminia; Somintac, Armando; Estacio, Elmer; Salvador, Arnel; Yamamoto, Kohji; Hase, Muneaki; Tani, Masahiko

    2016-11-14

    We present the use of a "double optical pump" technique in terahertz time-domain emission spectroscopy as an alternative method to investigate the lifetime of photo-excited carriers in semiconductors. Compared to the commonly employed optical pump-probe transient photo-reflectance, this non-contact and room temperature characterization technique allows relative ease in achieving optical alignment. The technique was implemented to evaluate the carrier lifetime in low temperature-grown gallium arsenide (LT-GaAs). The carrier lifetime values deduced from "double optical pump" THz emission decay curves show good agreement with data obtained from standard transient photo-reflectance measurements on the same LT-GaAs samples grown at 250 °C and 310 °C.

  13. Linear and nonlinear optical characterization of methyl-p-hydroxybenzoate (p-MHB) single crystal grown by TSSG method

    NASA Astrophysics Data System (ADS)

    Sritharan, K.; Manikandan, V.; Srinivasan, K.

    2017-06-01

    The nonlinear optical single crystal methyl-p-hydroxybenzoate (p-MHB) was grown by employing top seeded solution growth method (TSSG) for the first time. A good quality small size crystal grown from methanol solution was inserted into the melt as a seed for growth after seasoning it around the melt temperature. Highly transparent optical quality p-MHB single crystal with regular faceting was harvested after the successful growth run. The unit cell parameter of the grown crystal was determined by powder X-ray diffraction (PXRD) and the crystal structure was confirmed by single crystal X-ray diffraction (SCXRD) methods. The UV-Vis-NIR absorption spectrum has been recorded in the range 200-2700 nm and it shows that the lower cutoff wavelength exits at 307 nm. The study indicates that the grown crystal has good optical transparency window in the visible and near IR region in the range 307-2136 nm. Second harmonic generation (SHG) efficiency of the grown crystal was studied by Kurtz-Perry powder method with 1064 nm Nd: YAG laser beam as a fundamental source and it was about twice that the standard KDP.

  14. Study of post annealing effects on structural and optical properties of sol-gel derived ZnO thin films grown on n-Si substrate

    NASA Astrophysics Data System (ADS)

    Bahadur Yadav, Aniruddh; Periasamy, C.; Jit, S.

    2015-02-01

    Zinc oxide (ZnO) thin films were grown on n-type silicon (100) substrates by sol- gel spin coating technique. The prepared thin films were annealed in the presence of Ar at three different temperatures (at 450°C, 550°C and 650°C) to study the impact of annealing temperature on the structural and optical properties of the ZnO thin films. The structural, surface morphology and optical properties of the thin film were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) measurements respectively. The grown ZnO thin films are polycrystalline in nature with wurtzite hexagonal structure as evident from the XRD and SEM analyses. It further indicates that the crystalline size increases with increasing annealing temperature. The post annealing is also found to influence the optical properties in the terms of band gap energy of the ZnO thin films. The optical energy band gap was found to be decreased from 3.205 to 3.13eV as the annealing temperature is increased from 450°C to 650°C. However, our results concerning the growth of ZnO thin films on Si substrates suggest that there is an intermediate growth temperature allowing for the optimization of the ZnO film growth. The results of the study can be used as a guideline for growing ZnO thin films on n-Si substrates with a homogenous surface morphology, high surface to volume ratio and desired particle size, which are suited for optoelectronic/ gas sensing applications.

  15. Label-free optical detection of cells grown in 3D silicon microstructures.

    PubMed

    Merlo, Sabina; Carpignano, Francesca; Silva, Gloria; Aredia, Francesca; Scovassi, A Ivana; Mazzini, Giuliano; Surdo, Salvatore; Barillaro, Giuseppe

    2013-08-21

    We demonstrate high aspect-ratio photonic crystals that could serve as three-dimensional (3D) microincubators for cell culture and also provide label-free optical detection of the cells. The investigated microstructures, fabricated by electrochemical micromachining of standard silicon wafers, consist of periodic arrays of silicon walls separated by narrow deeply etched air-gaps (50 μm high and 5 μm wide) and feature the typical spectral properties of photonic crystals in the wavelength range 1.0-1.7 μm: their spectral reflectivity is characterized by wavelength regions where reflectivity is high (photonic bandgaps), separated by narrow wavelength regions where reflectivity is very low. In this work, we show that the presence of cells, grown inside the gaps, strongly affects light propagation across the photonic crystal and, therefore, its spectral reflectivity. Exploiting a label-free optical detection method, based on a fiberoptic setup, we are able to probe the extension of cells adherent to the vertical silicon walls with a non-invasive direct testing. In particular, the intensity ratio at two wavelengths is the experimental parameter that can be well correlated to the cell spreading on the silicon wall inside the gaps.

  16. Optical investigations of Be doped ZnO films grown by molecular beam epitaxy

    SciTech Connect

    Chen, Mingming; Zhu, Yuan; Chen, Anqi; Shen, Zhen; Tang, Zikang

    2016-06-15

    Highlights: • The optical properties of Be doped ZnO films were investigated. • Low temperature photoluminescence spectrum was dominated by D°X and DAP emissions. • Shallow acceptor state with ionization energy of 116 meV was found in ZnO:Be films. • It is suggested that the incorporated Be atom might favor formation of Zn vacancies defects. • This work demonstrates that N doping BeZnO might be suitable for fabricating reliable p-type ZnO materials. - Abstract: In this article, the optical properties of ZnO:Be films grown by plasma-assisted molecular beam epitaxy were investigated by the excitation density-dependent and temperature-dependent photoluminescence measurements. The low temperature photoluminescence spectra showed a dominant excitons bound to neutral donors (D°X) emission centered at 3.3540 eV and strong donor-acceptor pair (DAP) transitions at 3.3000 eV. In addition, it showed that the intensity ratio of the DAP and D°X peaks changed with background electron concentration. Furthermore, a shallow acceptor state with ionization energy of 116 meV was found and attributed to Zn vacancy. The present study further suggests that Be and N codoping ZnO might be suitable for fabricating reliable p-type ZnO materials.

  17. Repair of a mirror coating on a large optic for high laser damage applications using ion milling and over-coating methods

    DOE PAGES

    Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

    2016-07-08

    Here, when an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched.more » Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO2 and SiO2 layers for high reflection at 1054 nm at 45 deg incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 to 61.0 J/cm2.« less

  18. Repair of a Mirror Coating on a Large Optic for High Laser Damage Applications using Ion Milling and Over-Coating Methods.

    DOE PAGES

    Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

    2016-06-01

    When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface, and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairsmore » were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO2 and SiO2 layers for high reflection at 1054 nm at 45° incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm2. Finally, the repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 – 61.0 J/cm2.« less

  19. Repair of a Mirror Coating on a Large Optic for High Laser Damage Applications using Ion Milling and Over-Coating Methods.

    SciTech Connect

    Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

    2016-06-01

    When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface, and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO2 and SiO2 layers for high reflection at 1054 nm at 45° incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm2. Finally, the repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 – 61.0 J/cm2.

  20. Repair of a Mirror Coating on a Large Optic for High Laser Damage Applications using Ion Milling and Over-Coating Methods.

    SciTech Connect

    Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

    2016-06-01

    When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface, and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO2 and SiO2 layers for high reflection at 1054 nm at 45° incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm2. Finally, the repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 – 61.0 J/cm2.

  1. Repair of a mirror coating on a large optic for high laser damage applications using ion milling and over-coating methods

    SciTech Connect

    Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

    2016-07-08

    Here, when an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO2 and SiO2 layers for high reflection at 1054 nm at 45 deg incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 to 61.0 J/cm2.

  2. Sputter-Coated Microparticle Additives for Tailored Optical Properties

    DTIC Science & Technology

    2016-09-01

    physical, and electromagnetic properties, which are useful in the additive industry for modifying bulk polymer and composite materials. Previous...shaking mechanism as in Baechle et al.1 using an external electromagnetic shaker. The results of elemental analysis on the flat wafer coatings are...spectrometer Lamda 1050) for reflectance of the coatings in the visible spectrum . Coating thickness, as measured by RBS, was used to calculate the

  3. Study on structural and optical properties of TiO2 ALD coated silicon nanostructures

    NASA Astrophysics Data System (ADS)

    Pavlenko, Mykola; Myndrul, Valerii; Iatsunskyi, Igor; Jurga, Stefan; Smyntyna, Valentyn

    2016-04-01

    Structural and optical properties of TiO2 ALD coated silicon nanostructures were investigated. The morphology and chemical composition of TiO2 coated silicon nanopillars and porous silicon were studied by using methods of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Optical characteristics were studied using measurements of reflectance and luminescence spectra. Detailed analysis of morphological features and photoluminescence mechanisms were provided. Peculiarities of reflectance spectra were discussed. It was shown the possible application of these structures as antireflectance coatings.

  4. Investigation of microwave transitions and nonlinear magneto-optical rotation in anti-relaxation-coated cells

    SciTech Connect

    Budker, D.; Hollberg, L.; Kimball, D.F.; Kitching, J.; Pustclny, S.; Robinson, H.G.; Yashchuk, V.V.

    2004-06-04

    Using laser optical pumping, widths and frequency shifts are determined for microwave transitions between the components of the ground-state hyperfine structure for {sup 85}Rb and {sup 87}Rb atoms contained in vapor cells with alkane anti-relaxation coatings. The results are compared with data on Zeeman relaxation obtained in nonlinear magneto-optical rotation (NMOR) experiments, a comparison important for quantitative understanding of spin-relaxation mechanisms in coated cells. By comparing cells manufactured over a forty-year period we demonstrate the long-term stability of coated cells, which may be useful for atomic clocks and magnetometers.

  5. Microwave transitions and nonlinear magneto-optical rotation in anti-relaxation-coated cells

    SciTech Connect

    Budker, Dmitry; Hollberg. Leo; Kimball, Derek F.; Kitching J.; Pustelny Szymon; Yashchuk, Valeriy V.

    2004-08-12

    Using laser optical pumping, widths and frequency shifts are determined for microwave transitions between ground-state hyperfine components of {sup 85}Rb and {sup 87}Rb atoms contained in vapor cells with alkane anti-relaxation coatings. The results are compared with data on Zeeman relaxation obtained in nonlinear magneto-optical rotation (NMOR) experiments, a comparison important for quantitative understanding of spin-relaxation mechanisms in coated cells. By comparing cells manufactured over a forty-year period we demonstrate the long-term stability of coated cells, an important property for atomic clocks and magnetometers.

  6. Microwave transitions and nonlinear magneto-optical rotation in anti-relaxation-coated cells

    SciTech Connect

    Budker, D.; Hollberg, L.; Kitching, J.; Kimball, D.F.; Pustelny, S.; Yashchuk, V.V.

    2005-01-01

    Using laser optical pumping, widths and frequency shifts are determined for microwave transitions between ground-state hyperfine components of {sup 85}Rb and {sup 87}Rb atoms contained in vapor cells with alkane antirelaxation coatings. The results are compared with data on Zeeman relaxation obtained in nonlinear magneto-optical rotation experiments, a comparison important for quantitative understanding of spin-relaxation mechanisms in coated cells. By comparing cells manufactured over a 40-year period we demonstrate the long-term stability of coated cells, an important property for atomic clocks and magnetometers.

  7. Effect of Au coating on optical properties of CdS nanoparticles and their optical limiting studies

    NASA Astrophysics Data System (ADS)

    Mathew, S.; Samuel, Boni; Mujeeb, A.; Kailasnath, M.; Nampoori, V. P. N.; Girijavallabhan, C. P.

    2017-10-01

    We synthesized Au coated CdS nanoparticles by a novel synthesis route in which CdS is acting as a core. Transmission electron microscopy of the prepared CdS and Au coated nanoparticles shows that the size of the nanoparticles are in the range of 5 nm. TEM elemental maps of the Au coated CdS nanoparticles confirms the presence of Au nanoparticles on the surface of CdS nanoparticles. Nonlinear optical characteristics of these nanoparticles embedded in PVA thin films were studied by the Z-scan technique using Q-switched nanosecond Nd:YAG laser (532 nm). An enhancement in nonlinear optical property was observed for the prepared Au coated CdS embedded PVA nanocomposite films compared to that of bare CdS embedded PVA nanocomposite films. Nonlinear optical absorption coefficient and positive nonlinear refractive index of these films were measured to be 6.28 × 10-6cm/W and 4.86 × 10-11 cm2/W respectively. Au coated CdS nanoparticles embedded PVA film possesses a low limiting threshold of 34 MW/cm2 and also possess good positive nonlinear refractive index making suitable for optical limiting and optical switching applications.

  8. Angular scattering from optical interference coatings: scalar scattering predictions and measurements.

    PubMed

    Zavislan, J M

    1991-06-01

    A scalar scattering theory is developed that predicts the angular distribution of light scattered and the total integrated scatter from a randomly rough or inhomogeneous optical interference coating. Three types of random variation are considered: uncorrelated roughness, additive roughness, and uncorrelated index inhomogeneity. The scattering calculations are formulated so that the output of any conventional thin film analysis program along with a coating's surface or index statistics could be used to calculate the scattering distribution of a coating. The scattering calculations are compared to experimental measurements from a sixteen-layer high reflector coating with small additive roughness sigma = 2.4 A and large correlated roughness sigma = 93 A.

  9. Soft-x-ray hollow fiber optics with inner metal coating

    SciTech Connect

    Matsuura, Yuji; Oyama, Tadaaki; Miyagi, Mitsunobu

    2005-10-10

    A glass capillary with an inner metal coating is proposed to be used as soft-x-ray fiber optics in medical applications. Based on the results of theoretical calculations, nickel was chosen as the coating material for x rays radiated from a conventional x-ray tube. A nickel-coated capillary was fabricated by electroless deposition, and focusing and collimating effects were observed from measurements of the transmission efficiency of soft x rays. The transmission of a nickel-coated capillary with an inner diameter of 0.53 mm and a length of 300 mm was 10%, which is approximately double that of an uncoated glass capillary.

  10. Deep-ultraviolet antireflective coating with improved conformality, optical density, and etch rate

    NASA Astrophysics Data System (ADS)

    Guerrero, Douglas J.; Meador, James D.; Xu, Gu; Suzuki, Hitoshi; Sone, Yasuhisa; Krishnamurthy, Vandana N.; Claypool, James B.; Lamb, James E., III

    1998-06-01

    A new bottom antireflective coating (BARC) for 248 nm lithography is described. The new coating has an optical density of approximately 10/micrometers (k equals 0.41 and n equals 1.482) and plasma etches at rates higher than that of DUV resists depending on the etch conditions. Coating conformality is superior to older generation BARCs, also contributing to improved etch dynamics. Excellent 0.25 micrometers features have been obtained with ESCAP, Acetal and t-BOC type photoresists. The new BARC is spin coated from safe solvents and is spin bowl compatible with EBR and photoresist solvents.

  11. Low temperature and UV curable sol-gel coatings for long lasting optical fiber biosensors

    NASA Astrophysics Data System (ADS)

    Otaduy, D.; Villar, A.; Gomez-Herrero, E.; Goitandia, A. M.; Gorritxategi, E.; Quintana, I.

    2010-04-01

    The use of optical fibers as sensing element is increasing in clinical, pharmaceutical and industrial applications. Excellent light delivery, long interaction length, low cost and ability not only to excite the target molecules but also to capture the emitted light from the targets are the hallmarks of optical fiber as biosensors. In biosensors based on fiber optics the interaction with the analyte can occur within an element of the optical fiber. One of the techniques for this kind of biosensors is to remove the fiber optic cladding and substitute it for biological coatings that will interact with the parameter to sensorize. The deposition of these layers can be made by sol-gel technology. The sol-gel technology is being increasingly used mainly due to the high versatility to tailor their optical features. Incorporation of suitable chemical and biochemical sensing agents have allowed determining pH, gases, and biochemical species, among others. Nonetheless, the relatively high processing temperatures and short lifetime values mean severe drawbacks for a successful exploitation of sol-gel based coated optical fibres. With regard to the latter, herein we present the design, preparation and characterization of novel sol-gel coated optical fibres. Low temperature and UV curable coating formulations were optimized to achieve a good adhesion and optical performance. The UV photopolymerizable formulation was comprised by glycidoxypropyltrimethoxysilane (GLYMO), Tetraethylorthosilicate (TEOS) and an initiator. While the thermoset coating was prepared by using 3-aminopropyltrimethoxysilane, GLYMO, and TEOS as main reagents. Both curable sol-gel coated fibres were analysed by FTIR, SEM and optical characterization. Furthermore, in the present work a new technique for silica cladding removal has been developed by ultra-short pulses laser processing, getting good dimensional accuracy and surface integrity.

  12. Structural Properties of Potexvirus Coat Proteins Detected by Optical Methods.

    PubMed

    Semenyuk, P I; Karpova, O V; Ksenofontov, A L; Kalinina, N O; Dobrov, E N; Makarov, V V

    2016-12-01

    It has been shown by X-ray analysis that cores of coat proteins (CPs) from three potexviruses, flexible helical RNA-containing plant viruses, have similar α-helical structure. However, this similarity cannot explain structural lability of potexvirus virions, which is believed to determine their biological activity. Here, we used circular dichroism (CD) spectroscopy in the far UV region to compare optical properties of CPs from three potexviruses with the same morphology and similar structure. CPs from Alternanthera mosaic virus (AltMV), potato aucuba mosaic virus (PAMV), and potato virus X (PVX) have been studied in a free state and in virions. The CD spectrum of AltMV virions was similar to the previously obtained CD spectrum of papaya mosaic virus (PapMV) virions, but differed significantly from the CD spectrum of PAMV virions. The CD spectrum of PAMV virions resembled in its basic characteristics the CD spectrum of PVX virions characterized by molar ellipticity that is abnormally low for α-helical proteins. Homology modeling of the CP structures in AltMV, PAMV, and PVX virions was based on the known high-resolution structures of CPs from papaya mosaic virus and bamboo mosaic virus and confirmed that the structures of the CP cores in all three viruses were nearly identical. Comparison of amino acid sequences of different potexvirus CPs and prediction of unstructured regions in these proteins revealed a possible correlation between specific features in the virion CD spectra and the presence of disordered N-terminal segments in the CPs.

  13. Microstructural behavior of nitriding compound layer for Nb-carbonitride coating grown by thermo-reactive diffusion process

    NASA Astrophysics Data System (ADS)

    Lee, Kyunghoon; Kang, Namhyun; Bae, Jong-Seong; Lee, Chang-Woo

    2016-09-01

    This study aims to understand the microstructural behavior of nitriding compound layer and its effect on Nb-carbonitride growth produced by the thermo-reactive diffusion (TRD) process. Gas nitriding was performed at 550 °C for 3 and 6 h, followed by TRD at 900 °C for 6 h. The nitriding compound layers had thicknesses of 10 and 16 μm for nitriding time of 3 and 6 h, respectively. The corresponding Nb-carbonitride layers produced by TRD were 7.2 and 11.2 μm thick, respectively. Reheating at 900 °C transformed the microstructure of the nitriding compounds to Fe3O4 and FeN0.0939. As reheating proceeded to 30 min, high concentration of nitrogen, initially existing in the nitride layer diffused to 80-90 μm into the substrate. Therefore, the TRD process produced NbN layer at the interfacial area due to intensively dissolved nitrogen from FeN0.0939. As the TRD proceeded, supply of C atoms from the base metal became competitive with the N diffusion. Thus, the TRD coating layer was grown to above the interface. Reheating at 900 °C for the 16-μm-thick nitride layer resulted in a nitrogen content ˜0.4 at% higher than that for the 10-μm-thick nitride layer, thereby producing a thicker Nb-carbonitride layer.

  14. The effect of time on optical coating mechanical loss and implications for LIGO-India

    NASA Astrophysics Data System (ADS)

    Kinley-Hanlon, Maya; Fair, Hannah M.; Jiffar, Isaac; Newport, Jonathan; Gitelman, Louis; Harry, Gregory; Billingsley, Garilynn; Penn, Steve

    2016-07-01

    We report on the persistence of mechanical loss with time of ion beam sputtered dielectric coatings made from alternating layers of Ta2O5 and SiO2 deposited onto fused silica substrates. From this, we predict the coating thermal noise in gravitational wave interferometers, after the coated optics have been stored for years. We measured the modal mechanical quality factor, Q, of two coated fused silica samples in 2015. These samples also had their modal Q's measured in 2002. We conclude that storing the coated silica disks for 13 years does not change their mechanical loss and thus the storage of Advanced LIGO gravitational wave detector optics until their future installation in India will not degrade their achievable thermal noise.

  15. Optical and mechanical behavior of GeC and BP antireflection coatings under rain erosion tests

    NASA Astrophysics Data System (ADS)

    Mackowski, Jean-Marie; Cimma, B.; Lacuve, J.; Laprat, Patrice

    1994-09-01

    Thick germanium carbide (GeC) and boron phosphide (BP) films are successfully grown on various zinc sulfide and germanium substrates at temperatures up to 450 degree(s)C by reactive radio-frequency sputtering (RRFS). The sputtering conditions are respectively a germanium target within a medium of methane-argon for GeC films and a high density boron target in a sputtering medium of phosphine-argon for BP films. The rain erosion resistance of GeC and BP films protected or not by diamond-like carbon (DLC) coating on top are measured for water drop diameter of 1.2 mm or 2 mm with an impact velocity ranging from 210 m/s to 265 m/s on the Saab-Scania whirling-arm rig facilities (Linkoping, Sweden). Rain erosion resistance of BP films for a wavelength band in the 8 micrometers to 10 micrometers range shows no damage for a speed up to 250 m/s with an exposure time up to 10 min, whereas the GeC rain erosion resistance shows no damage up to 235 m/s for the same exposure time. The transmission of each film is well correlated to its optical absorption at 10.6 micrometers . The GeC absorption can be reduced down to 40 cm-1 whereas the BP absorption stays around 220 cm-1 for sputtered films. So the compromise between the optical performance and the rain erosion resistance can be achieved by the use of GeC or BP films.

  16. Formation process of Si3N4 particles on surface of Si ingots grown using silica crucibles with Si3N4 coating by noncontact crucible method

    NASA Astrophysics Data System (ADS)

    Nakajima, Kazuo; Morishita, Kohei; Murai, Ryota; Usami, Noritaka

    2014-03-01

    A noncontact crucible method was used to investigate the process by which a Si3N4 coating material forms Si3N4 particles or precipitates on the surface of Si melts and ingots. Si ingots were grown using crucibles with and without a mixture of α- and β-Si3N4 particles. The oxygen and nitrogen concentrations in the ingots were measured by Fourier transform infrared spectrometry analysis. The nitrogen concentration in the ingots grown using crucibles with a Si3N4 coating was significantly higher than that in ingots grown using crucibles without a Si3N4 coating because the nitrogen from the Si3N4 coating material dissolved into the Si melt. From orientation image maps analyzed using electron backscattering diffraction patterns of SixNy particles on the surface of the ingots, it was clarified that most of the SixNy particles were β-Si3N4. This was also confirmed by X-ray diffraction measurements. The Si3N4 particles on the surface of the ingots had several morphologies such as needle-like, columnar, leaf-like, and hexagonal structures. There were two cases in which floating Si3N4 particles were formed on the surface of the Si melts, i.e., the removal and dissolution of the Si3N4 coating material. The removed or dissolved Si3N4 coating materials, which consisted of a mixture of α- and β-Si3N4 particles, are considered to have finally changed into β-Si3N4 in the form of transformers or precipitates on the surface of the Si melt, and these β-Si3N4 particles became attached to the surface of the ingots.

  17. Perspective on electrodeposited and electroless nickel coatings used in optical applications

    SciTech Connect

    Sanger, G.M.; Dini, J.W.

    1982-01-04

    Electrodeposits of copper, gold, silver and electroless nickel coatings are playing an ever more important role in optical technology. Any material that can be adherently coated with these deposits can be finished by conventional polishing or diamond turning techniques, thus greatly expanding design strategies and supporting manufacturing capability for optical surfaces. The importance of good quality coatings, e.g., the absence of surface pits, porosity, nodules, stress and inclusions large enough to damage the diamond tool or adversely effect conventional polishing process are emphasized and information is presented on influence of plating defects on optics. Recent data on the diamond turning and polishing of other electrodeposited coatings including bright nickel, sulfamate nickel and tin-nickel are also included.

  18. Optical and environmentally protective coatings for potassium dihydrogen phosphate (KDP) harmonic converter crystals

    SciTech Connect

    Thomas, I.M.

    1991-06-24

    Potassium dihydrogen phosphate (KDP) crystals have been used as harmonic converters on the Nova laser at LLNL for over six years. All crystals were coated with a single layer, quarterwave AR coating of porous silica with a refractive index of 1.22. This was prepared by a sol-gel process and was applied from a colloidal suspension by spin coating at room temperature. A few crystals were also coated with a methyl silicone coating prior to the application of the AR coating for environmental protection. The initial optical performance of all crystals was very good but there has been some deterioration over the years because of environmental and laser damage degradation. The deterioration in the silicone samples was, however, much less than the others. We are now in the process of replacing all ten KDP arrays with new crystals and will apply the silicone undercoat to all samples. Recently we have been evaluating a new perfluorinated organic polymer coating which has a refractive index of 1.29. This material is soluble in fluorinated solvents and can be applied by dip coating from solution at room temperature. We hope that this can provide environmental protection when applied to KDP and also act as an AR coating at the same time. The optical performance is not as good as our porous silica because of the higher index; about 0.3% reflection per surface is obtained. 4 refs., 10 figs., 1 tab.

  19. How smooth chemistry allows high-power laser optical coating preparation

    NASA Astrophysics Data System (ADS)

    Belleville, Philippe F.; Prene, Philippe; Bonnin, Claude; Beaurain, Laurence; Montouillout, Yves; Lavastre, Eric

    2004-02-01

    For fifty years, a considerable effort has been and is still being directed to the production of optical coatings using liquid deposition route. Sol-Gel is a chemical process widely used for oxide material preparation. Based on smooth chemistry (low temperature conditions), sol-gel allows nanoparticle and polymeric material synthesis dispersed in appropriate liquid medium. The process investigated at CEA (French Commission for Atomic Energy) is strongly developed to afford coatings onto mineral or metallic substrates using colloidal oxide-based and/or inorganic-organic hybrid materials. Such a chemical process is sufficiently adjustable to develop purpose-built materials and coatings for high power laser optical components, taking into account the high laser damage threshold requirement. Because the CEA megajoule-class pulsed laser is needing 7,000-m2 of coated area onto 10,000 large-sized optical components, we have developed to date, several optical coating procedures, each optical thin film being prepared from a specific material and deposition process. First need to fulfil was the antireflective (AR) coating required for transparent optics and used to increase laser light transmission and to suppress damaging residual reflection. The as-developed AR-coatings were made of nanosized particle-containing fragile single layer or abrasion-resistant polymeric-based broadband layer stack. For used on highly-reflective (HR) component, a specific unstressed multilayer coating has been developed and deposited onto deformable adaptative end-cavity mirror substrate. This HR-coating is made of quaterwave stack of colloidal-based low index and hybrid high index thin films. Using such materials, first high ratio polarizing sol-gel coatings have been also produced. Apart optical coating preparation, sol-gel chemistry has been used to develop an hybrid dense protective thin film to enhance durability of oxidation-sensitive silver cavity reflectors. Each coating material

  20. Tuning physical and optical properties of ZnO nanowire arrays grown on cotton fibers.

    PubMed

    Athauda, Thushara J; Hari, Parameswar; Ozer, Ruya R

    2013-07-10

    This article reports the first systematic study on the quantitative relationship between the process parameters of solution concentration ratio, structure, and physical and optical properties of ZnO nanowires grown on cotton surfaces. To develop a fundamental understanding concerning the process-structure-activity relations, we grew a series of well-defined, radially oriented, highly dense, and uniform single-crystalline ZnO nanorods and nanoneedles on cotton surfaces by a simple and inexpensive two-step optimized hydrothermal process at a relatively low temperature. This process involves seed treatment of a cotton substrate with ZnO nanocrystals that will serve as the nucleation sites for subsequent anisotropic growth of single crystalline ZnO nanowires. All of the ZnO nanowires exhibit wurtzite crystal structure oriented along the c-axis. For investigating structure-controlled properties, seed-to-growth solutions concentrations ratio ([S]/[G]) of the synthesis process was varied over six different values. Superhydrophobicity was achieved for all morphologies after 1-dodecanethiol modification, which was highly durable after prolonged UV irradiation. Durability of the ZnO materials under laundry condition was also verified. Variation of the [S]/[G] ratio resulted in a morphological transform from nanorods to needle-like structures in conjunction with a drastic change in the physical and optical properties of the ZnO modified cotton surfaces. Higher [S]/[G] ratios yielded formation of ZnO nanoneedles with high degree of crystallinity and higher aspect ratio compared to nanorods. Increasing [S]/[G] ratio resulted in the amount of ZnO grown on the cotton surface to drop significantly, which also caused a decrease in the surface hydrophobicity and UV absorption. In addition, room temperature photoluminescence measurements revealed that the band gap of ZnO widened and the structural defects were reduced as the morphology changed from nanorods to nanoneedles. A similar

  1. Spacecraft materials guide. [including: encapsulants and conformal coatings; optical materials; lubrication; and, bonding and joining processes

    NASA Technical Reports Server (NTRS)

    Staugaitis, C. L. (Editor)

    1975-01-01

    Materials which have demonstrated their suitability for space application are summarized. Common, recurring problems in encapsulants and conformal coatings, optical materials, lubrication, and bonding and joining are noted. The subjects discussed include: low density and syntactic foams, electrical encapsulants; optical glasses, interference filter, mirrors; oils, greases, lamillar lubricants; and, soldering and brazing processes.

  2. Multilayer coated optics for an alpha-class extreme ultraviolet lithography system

    SciTech Connect

    Folta, J A; Grabner, R F; Hudyma, R M; Montcalm, C; Schmidt, M A; Spiller, E; Walton, C C; Wedowski, M

    1999-08-25

    We present the results of coating the first set of optical elements for an alpha-class extreme-ultraviolet (EUV) lithography system, the Engineering Test Stand (ETS). The optics were coated with Mo/Si multilayer mirrors using an upgraded DC-magnetron sputtering system. Characterization of the near-normal incidence EUV reflectance was performed using synchrotron radiation from the Advanced Light Source at the Lawrence Berkeley National Laboratory. Stringent requirements were met for these multilayer coatings in terms of reflectance, wavelength matching among the different optics, and thickness control across the diameter of each individual optic. Reflectances above 65% were achieved at 13.35 nm at near-normal angles of incidence. The run-to-run reproducibility of the reflectance peak wavelength was maintained to within 0.4%, providing the required wavelength matching among the seven multilayer-coated optics. The thickness uniformity (or gradient) was controlled to within {+-}0.25% peak-to-valley (P-V) for the condenser optics and {+-}0.1% P-V for the four projection optics, exceeding the prescribed specification for the optics of the ETS.

  3. Epoxy-based broadband antireflection coating for millimeter-wave optics.

    PubMed

    Rosen, Darin; Suzuki, Aritoki; Keating, Brian; Krantz, William; Lee, Adrian T; Quealy, Erin; Richards, Paul L; Siritanasak, Praween; Walker, William

    2013-11-20

    We have developed epoxy-based, broadband antireflection coatings for millimeter-wave astrophysics experiments with cryogenic optics. By using multiple-layer coatings where each layer steps in dielectric constant, we achieved low reflection over a wide bandwidth. We suppressed the reflection from an alumina disk to 10% over fractional bandwidths of 92% and 104% using two-layer and three-layer coatings, respectively. The dielectric constants of epoxies were tuned between 2.06 and 7.44 by mixing three types of epoxy and doping with strontium titanate powder required for the high dielectric mixtures. At 140 K, the band-integrated absorption loss in the coatings was suppressed to less than 1% for the two-layer coating, and below 10% for the three-layer coating.

  4. Optical properties of strain-free AlN nanowires grown by molecular beam epitaxy on Si substrates

    SciTech Connect

    Wang, Q.; Zhao, S.; Connie, A. T.; Shih, I.; Mi, Z.; Gonzalez, T.; Andrews, M. P.; Du, X. Z.; Lin, J. Y.; Jiang, H. X.

    2014-06-02

    The optical properties of catalyst-free AlN nanowires grown on Si substrates by molecular beam epitaxy were investigated. Such nanowires are nearly free of strain, with strong free exciton emission measured at room temperature. The photoluminescence intensity is significantly enhanced, compared to previously reported AlN epilayer. Moreover, the presence of phonon replicas with an energy separation of ∼100 meV was identified to be associated with the surface-optical phonon rather than the commonly reported longitudinal-optical phonon, which is further supported by the micro-Raman scattering experiments.

  5. Optical polarization characteristics of m-plane GaN/AlGaN quantum well structures grown on m-plane SiC substrate

    NASA Astrophysics Data System (ADS)

    Park, Seoung-Hwan; Ahn, Doyeol

    2015-12-01

    Optical polarization characteristics of m-plane GaN/AlGaN QW structures grown on m-plane SiC substrate were theoretically investigated using the multiband effective-mass theory. The QW structure grown on SiC substrate shows much larger in-plane optical polarization than that grown on GaN substrate. This is attributed to the fact that the QW structure grown on SiC substrate has larger y‧-polarized optical emission and smaller x‧-polarized optical emission than the QW structure grown on GaN substrate. Also, the magnitude of the optical polarization is found to depend on the carrier density and decrease gradually with increasing carrier density. This can be explained by the fact that, with increasing k∥, the x‧-polarized matrix element increases while the y‧-polarized matrix element rapidly decreases.

  6. Mid-infrared to ultraviolet optical properties of InSb grown on GaAs by molecular beam epitaxy

    SciTech Connect

    D'Costa, Vijay Richard Yeo, Yee-Chia; Tan, Kian Hua; Jia, Bo Wen; Yoon, Soon Fatt

    2015-06-14

    Spectroscopic ellipsometry was used to investigate the optical properties of an InSb film grown on a GaAs (100) substrate, and to compare the optical properties of InSb film with those of bulk InSb. The film was grown by molecular beam epitaxy under conditions intended to form 90° misfit dislocations at the InSb-GaAs interface. The complex dielectric function obtained in a wide spectroscopic range from 0.06–4.6 eV shows the critical point transitions E{sub 0}, E{sub 1}, E{sub 1} + Δ{sub 1}, E{sub 0}{sup ′}, and E{sub 2}. The amplitudes, energy transitions, broadenings, and phase angles have been determined using a derivative analysis. Comparing film and bulk critical point results reveal that the epitaxial film is nearly relaxed and has bulk-like optical characteristics.

  7. Optical characterization of an unknown single layer: Institut Fresnel contribution to the Optical Interference Coatings 2004 Topical Meeting Measurement Problem.

    PubMed

    Lemarchand, Fabien; Deumié, Carole; Zerrad, Myriam; Abel-Tiberini, Laëtitia; Bertussi, Bertrand; Georges, Gaëlle; Lazaridès, Basile; Cathelinaud, Michel; Lequime, Michel; Amra, Claude

    2006-03-01

    We present the characterizations performed at the Institut Fresnel for the Measurement Problem of the Optical Interference Coatings 2004 Topical Meeting. A single layer coated on a fused-silica substrate of unknown composition and parameters is analyzed in terms of optogeometrical parameters, uniformity, and scattering. We determine the refractive index and the average thickness of the coating, then provide the localized determination of the thickness with a 2 mm spatial resolution. Topography measurements include atomic force microscopy and angle-resolved scattering measurements. These results are completed thanks to a Taylor Hobson noncontact 3D surface profiler.

  8. Effects of Rapid Thermal Annealing on the Structural, Electrical, and Optical Properties of Zr-Doped ZnO Thin Films Grown by Atomic Layer Deposition.

    PubMed

    Wu, Jingjin; Zhao, Yinchao; Zhao, Ce Zhou; Yang, Li; Lu, Qifeng; Zhang, Qian; Smith, Jeremy; Zhao, Yongming

    2016-08-13

    The 4 at. % zirconium-doped zinc oxide (ZnO:Zr) films grown by atomic layer deposition (ALD) were annealed at various temperatures ranging from 350 to 950 °C. The structural, electrical, and optical properties of rapid thermal annealing (RTA) treated ZnO:Zr films have been evaluated to find out the stability limit. It was found that the grain size increased at 350 °C and decreased between 350 and 850 °C, while creeping up again at 850 °C. UV-vis characterization shows that the optical band gap shifts towards larger wavelengths. The Hall measurement shows that the resistivity almost keeps constant at low annealing temperatures, and increases rapidly after treatment at 750 °C due to the effect of both the carrier concentration and the Hall mobility. The best annealing temperature is found in the range of 350-550 °C. The ZnO:Zr film-coated glass substrates show good optical and electrical performance up to 550 °C during superstrate thin film solar cell deposition.

  9. Effects of Rapid Thermal Annealing on the Structural, Electrical, and Optical Properties of Zr-Doped ZnO Thin Films Grown by Atomic Layer Deposition

    PubMed Central

    Wu, Jingjin; Zhao, Yinchao; Zhao, Ce Zhou; Yang, Li; Lu, Qifeng; Zhang, Qian; Smith, Jeremy; Zhao, Yongming

    2016-01-01

    The 4 at. % zirconium-doped zinc oxide (ZnO:Zr) films grown by atomic layer deposition (ALD) were annealed at various temperatures ranging from 350 to 950 °C. The structural, electrical, and optical properties of rapid thermal annealing (RTA) treated ZnO:Zr films have been evaluated to find out the stability limit. It was found that the grain size increased at 350 °C and decreased between 350 and 850 °C, while creeping up again at 850 °C. UV–vis characterization shows that the optical band gap shifts towards larger wavelengths. The Hall measurement shows that the resistivity almost keeps constant at low annealing temperatures, and increases rapidly after treatment at 750 °C due to the effect of both the carrier concentration and the Hall mobility. The best annealing temperature is found in the range of 350–550 °C. The ZnO:Zr film-coated glass substrates show good optical and electrical performance up to 550 °C during superstrate thin film solar cell deposition. PMID:28773816

  10. Hard protective waterproof coating for high-power laser optical elements.

    PubMed

    Murahara, Masataka; Sato, Nobuhiro; Ikadai, Akimitsu

    2005-12-15

    We developed a new method for making a waterproof coating by photooxidation of silicone oil. The silicone oil was spin coated onto the surfaces of optical elements, i.e., a plastic lens, a laser mirror, and a nonlinear optical crystal, and then irradiated with a xenon excimer lamp in air, which transformed the organic silicone oil into an amorphous glass film. This technique has enabled an optical thin film to transmit ultraviolet rays of wavelengths below 200 nm and to exhibit the characteristics of homogeneity, high density, and resistance to environmental effects and to corrosion by water, and a Mohs scale value of 5.

  11. Manufacturing and coating of optical components for the EnMAP hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Schürmann, M.; Gäbler, D.; Schlegel, R.; Schwinde, S.; Peschel, T.; Damm, C.; Jende, R.; Kinast, J.; Müller, S.; Beier, M.; Risse, S.; Sang, B.; Glier, M.; Bittner, H.; Erhard, M.

    2016-07-01

    The optical system of the hyperspectral imager of the Environmental Mapping and Analysis Program (EnMAP) consists of a three-mirror anastigmat (TMA) and two independent spectrometers working in the VNIR and SWIR spectral range, respectively. The VNIR spectrometer includes a spherical NiP coated Al6061 mirror that has been ultra-precisely diamond turned and finally coated with protected silver as well as four curved fused silica (FS) and flint glass (SF6) prisms, respectively, each with broadband antireflection (AR) coating, while the backs of the two outer prisms are coated with a high-reflective coating. For AR coating, plasma ion assisted deposition (PIAD) has been used; the high-reflective enhanced Ag-coating on the backside has been deposited by magnetron sputtering. The SWIR spectrometer contains four plane and spherical gold-coated mirrors, respectively, and two curved FS prisms with a broadband antireflection coating. Details about the ultra-precise manufacturing of metal mirrors and prisms as well as their coating are presented in this work.

  12. R and AR optical coatings for high-power laser and for X, DUV, VIS, and IR wavelengths

    NASA Astrophysics Data System (ADS)

    Dumartin, Serge; Robert, Patrick; Hayer, Laurent

    2004-02-01

    Optical Components improvements generally call specific improvements of optical coatings. SESO introduce here, some examples of new coatings, developed for applications in its activity fields such as, space, defense, synchrotrons and high power laser programs, astronomy. To answer to a need of coating, in a very wide wavelength range, from X rays to FAR IR: - Metallic reflective coating for X Rays. - Specific Aluminium coating for EUV up to 190 nm - Dielectric coatings for wavelength broadband, double or triple bands (VIS + IR) To answer to a need of High Level Laser damage: - Hf/Metal coating (R and AR) to face energies up to 40J/cm2 To answer to a need of long lifetime for coatings submitted to stringent environmental conditions: - enhanced silver coating for astronomical mirrors - Hard Gold for Space applications - Protected aluminium for solar simulators To answer to a need of coating a large variety of substrates: - R and AR coatings on Silicium, ZnS, ZnSe, Ge, Saphyr... At least to answer to a need of high uniformity coatings and to realise coating on very large optical components, SESO recently installed a large coating machine able to work with optical components up to Φ 1100mm.

  13. Deep reactive ion etched anti-reflection coatings for sub-millimeter silicon optics.

    PubMed

    Gallardo, Patricio A; Koopman, Brian J; Cothard, Nicholas F; Bruno, Sarah Marie M; Cortes-Medellin, German; Marchetti, Galen; Miller, Kevin H; Mockler, Brenna; Niemack, Michael D; Stacey, Gordon; Wollack, Edward J

    2017-04-01

    Refractive optical elements are widely used in millimeter and sub-millimeter (sub-mm) astronomical telescopes. High-resistivity silicon is an excellent material for dielectric lenses given its low loss tangent, high thermal conductivity, and high index of refraction. The high index of refraction of silicon causes a large Fresnel reflectance at the vacuum-silicon interface (up to 30%), which can be reduced with an anti-reflection (AR) coating. In this work, we report techniques for efficiently AR coating silicon at sub-mm wavelengths using deep reactive ion etching (DRIE) and bonding the coated silicon to another silicon optic. Silicon wafers of 100 mm diameter (1 mm thick) were coated and bonded using the silicon direct bonding technique at high temperature (1100°C). No glue is used in this process. Optical tests using a Fourier transform spectrometer show sub-percent reflections for a single-layer DRIE AR coating designed for use at 320 μm on a single wafer. Cryogenic (10 K) measurements of a bonded pair of AR-coated wafers also reached sub-percent reflections. A prototype two-layer DRIE AR coating to reduce reflections and increase bandwidth is presented, and plans for extending this approach are discussed.

  14. Structural and optical properties of GaAsSb QW heterostructures grown by laser deposition

    SciTech Connect

    Zvonkov, B. N.; Vikhrova, O. V. Dorokhin, M. V.; Kalentyeva, I. L.; Morozov, S. V.; Kryzhkov, D. I.; Yunin, P. A.

    2015-01-15

    The possibility of using the laser deposition method to grow crystalline light-emitting structures with GaAsSb/GaAs quantum wells (QWs) is experimentally demonstrated for the first time. The growth temperature of the GaAs{sub 1−x}Sb{sub x} layers is varied within the range 450–550°C; according to X-ray diffraction analyses, the content of antimony reaches x{sub Sb} ≈ 0.37 at a growth temperature of 450°C. Low-temperature (4 K) photoluminescence spectroscopy demonstrates the presence of a peak associated with the GaAsSb/GaAs QW at around 1.3 μm at the minimum laser-light pumping level. The optimal growth temperature T{sub g} = 500°C and arsine flow rate P{sub A} = 2.2 × 10{sup −8} mol/s at which the best emission properties of QWs with x{sub Sb} ∼ 0.17–0.25 are observed at temperatures of 77 and 300 K are determined. It is shown that GaAsSb/GaAs QWs with similar parameters (width and composition) grown by laser deposition at 500°C and metal-organic vapor-phase epitaxy at 580°C have comparable optical quality.

  15. Optical waveguide loss minimized into gallium nitride based structures grown by metal organic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Stolz, A.; Cho, E.; Dogheche, E.; Androussi, Y.; Troadec, D.; Pavlidis, D.; Decoster, D.

    2011-04-01

    The waveguide properties are reported for wide bandgap gallium nitride (GaN) structures grown by metal organic vapor phase epitaxy on sapphire using a AlN/GaN short period-superlattice (SPS) buffer layer system. A detailed optical characterization of GaN structures has been performed using the prism coupling technique in order to evaluate its properties and, in particular, the refractive index dispersion and the propagation loss. In order to identify the structural defects in the samples, we performed transmission electron microscopy analysis. The results suggest that AlN/GaN SPS plays a role in acting as a barrier to the propagation of threading dislocations in the active GaN epilayer; above this defective region, the dislocations density is remarkably reduced. The waveguide losses were reduced to a value around 0.65dB/cm at 1.55 μm, corresponding to the best value reported so far for a GaN-based waveguide.

  16. Optical Gratings Coated with Thin Si3N4 Layer for Efficient Immunosensing by Optical Waveguide Lightmode Spectroscopy.

    PubMed

    Diéguez, Lorena; Caballero, David; Calderer, Josep; Moreno, Mauricio; Martínez, Elena; Samitier, Josep

    2012-04-10

    New silicon nitride coated optical gratings were tested by means of Optical Waveguide Lightmode Spectroscopy (OWLS). A thin layer of 10 nm of transparent silicon nitride was deposited on commercial optical gratings by means of sputtering. The quality of the layer was tested by x-ray photoelectron spectroscopy and atomic force microscopy. As a proof of concept, the sensors were successfully tested with OWLS by monitoring the concentration dependence on the detection of an antibody-protein pair. The potential of the Si3N4 as functional layer in a real-time biosensor opens new ways for the integration of optical waveguides with microelectronics.

  17. Anti-Reflective and Waterproof Hard Coating for High Power Laser Optical Elements

    NASA Astrophysics Data System (ADS)

    Murahara, Masataka; Yabe, Takashi; Uchida, Shigeaki; Yoshida, Kunio; Okamoto, Yoshiaki

    2006-05-01

    A hard coating method of single crystalline porous silica film is widely used for high power laser optical elements in the air. However, there is no protective hard coating method for the elements to survive high power laser irradiance while in the water. We, thus, developed a new method for a waterproof coating with photo-oxidation of silicone oil. The silicone oil was spin-coated onto the surface of optical elements, and then irradiated with a xenon excimer lamp in the air. In this treatment, a protective coating for plastic lenses, mirrors, and nonlinear optical crystals, which are highly deliquescent, was developed by taking advantage of the phenomenon in which organic silicone oil is transformed to inorganic amorphous glass by a process of photo-oxidation. This technique has enabled an optical thin coating film to transmit ultraviolet rays of wavelengths under 200 nm and possess the characteristics of homogeneity, high density, resistance to environment, anti-reflectiveness, resistance to water, and Mohs' scale of 5, which is comparable to apatite. This allows us to cool a slab laser head and use as a mirror for underwater laser welding.

  18. MFI-type zeolite functional liquid phase sensor coated on the optical fiber end-face

    NASA Astrophysics Data System (ADS)

    Hu, Yaoxin; Sidiroglou, Fotios; Hill, Matthew R.; Collins, Stephen F.; Duke, Mikel

    2012-02-01

    Optical fibers are a unique medium to coat with functional sensor materials that change in refractive index upon adsorption/interaction with specific compounds. In this work, we demonstrate a simple technique to coat the end face of an optical fiber with the microporous MFI-type zeolite. The exposure of the zeolite films from air to water or to aqueous solutions of ethanol and isopropanol causes a distinct change in the film's refractive index. This change was then detected using a simple fiber optic refractive index sensor by monitoring the signal intensity reflected back from the coated fiber endface and as the zeolite is transferred between air, water and solutions containing ethanol and isopropanol. The zeolite coating was developed using the in-situ templated growth technique to grow the zeolite crystals on the cleaved endface of an optical fiber. Effective coating was achieved when the fiber was oriented horizontally in the hydrothermal reactor. The zeolite coated end face reflected less energy in water, at 0.0201 μW, and exhibited almost no change (~2% increase) with increasing ethanol concentration, but exhibited a 135% increase in reflected energy, i.e. 0.048 μW, in 100% ethanol. The zeolite therefore gave the sensor alcohol selectivity. Further work is exploring applicability for liquid phase chemical and water quality analysis.

  19. Improving electro-optic window reliability with DIACER coatings

    NASA Astrophysics Data System (ADS)

    Carasso, M. L.; Adair, J. H.; Demkowicz, P. A.; Gilbert, D. G.; Singh, Rajiv K.

    1997-06-01

    Most commercial diamond synthesis processes involve some form of chemical vapor deposition (CVD) which results in heterogeneous nucleation on the surface of window or dome materials. Generally, these processes have relatively long deposition times driven by the slow CVD kinetics. An alternate method called DIACERTM uses an aqueous seed crystal dispersion applied to the window substrates prior to CVD. These seed crystals reduce nucleation times and speed CVD deposition rates. Thicker coatings can be produced by repeating the seeding/CVD cycle until the required thickness is achieved. This paper reviews DIACERTM coating results on silicon substrates. Scanning electron microscopy and atomic force microscopy images of images of the coatings are presented. IR transmission results are presented both before and after sand and rain erosion exposures. The results of this testing will show DICERTM coatings to durable for the protection of silicon substrates after exposure to severe sand environments.

  20. Electro-Optically Pumped Catalytic Coatings for Hydrolysis And Sensing

    DTIC Science & Technology

    2008-12-01

    periodic treatment also restores the coating to its initial physical characteristics. In particular, we discuss a mixed oxide photocatalyst coating...oxynitrides as compared to the redox potentials for reactions (1) and (2). For these to occur, the conduction band for any suitable photocatalyst ...particle size of the photocatalyst becomes smaller, the probability increases that an exciton can reach the mate- rial surface before recombination

  1. Simultaneous electrical and optical readout of graphene-coated high Q silicon nitride resonators

    NASA Astrophysics Data System (ADS)

    Adiga, V. P.; De Alba, R.; Storch, I. R.; Yu, P. A.; Ilic, B.; Barton, R. A.; Lee, S.; Hone, J.; McEuen, P. L.; Parpia, J. M.; Craighead, H. G.

    2013-09-01

    Resonant mechanics of high quality factor (Q) graphene coated silicon nitride devices have been explored using optical and electrical transduction schemes. With the addition of the graphene layer, we retain the desirable mechanical properties of silicon nitride but utilize the electrical and optical properties of graphene to transduce and tune the resonant motion by both optical and electrical means. By positioning the graphene-on-silicon-nitride drums in a tunable optical cavity, we observe position dependent damping and resonant frequency control of the devices due to optical absorption by graphene.

  2. Optically transparent and environmentally durable superhydrophobic coating based on functionalized SiO₂ nanoparticles.

    PubMed

    Schaeffer, Daniel A; Polizos, Georgios; Smith, D Barton; Lee, Dominic F; Hunter, Scott R; Datskos, Panos G

    2015-02-06

    Optical surfaces such as mirrors and windows that are exposed to outdoor environmental conditions are susceptible to dust buildup and water condensation. The application of transparent superhydrophobic coatings on optical surfaces can improve outdoor performance via a 'self-cleaning' effect similar to the Lotus effect. The contact angle (CA) of water droplets on a typical hydrophobic flat surface varies from 100° to 120°. Adding roughness or microtexture to a hydrophobic surface leads to an enhancement of hydrophobicity and the CA can be increased to a value in the range of 160°-175°. This result is remarkable because such behavior cannot be explained using surface chemistry alone. When surface features are on the order of 100 nm or smaller, they exhibit superhydrophobic behavior and maintain their optical transparency. In this work we discuss our results on transparent superhydrophobic coatings that can be applied across large surface areas. We have used functionalized silica nanoparticles to coat various optical elements and have measured the CA and optical transmission between 190 and 1100 nm on these elements. The functionalized silica nanoparticles were dissolved in a solution of the solvents, while the binder used was a polyurethane clearcoat. This solution was spin-coated onto a variety of test glass substrates, and following a curing period of about 30 min, these coatings exhibited superhydrophobic behavior with a static CA ≥ 160°.

  3. Optically transparent and environmentally durable superhydrophobic coating based on functionalized SiO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Schaeffer, Daniel A.; Polizos, Georgios; Barton Smith, D.; Lee, Dominic F.; Hunter, Scott R.; Datskos, Panos G.

    2015-02-01

    Optical surfaces such as mirrors and windows that are exposed to outdoor environmental conditions are susceptible to dust buildup and water condensation. The application of transparent superhydrophobic coatings on optical surfaces can improve outdoor performance via a ‘self-cleaning’ effect similar to the Lotus effect. The contact angle (CA) of water droplets on a typical hydrophobic flat surface varies from 100° to 120°. Adding roughness or microtexture to a hydrophobic surface leads to an enhancement of hydrophobicity and the CA can be increased to a value in the range of 160°-175°. This result is remarkable because such behavior cannot be explained using surface chemistry alone. When surface features are on the order of 100 nm or smaller, they exhibit superhydrophobic behavior and maintain their optical transparency. In this work we discuss our results on transparent superhydrophobic coatings that can be applied across large surface areas. We have used functionalized silica nanoparticles to coat various optical elements and have measured the CA and optical transmission between 190 and 1100 nm on these elements. The functionalized silica nanoparticles were dissolved in a solution of the solvents, while the binder used was a polyurethane clearcoat. This solution was spin-coated onto a variety of test glass substrates, and following a curing period of about 30 min, these coatings exhibited superhydrophobic behavior with a static CA ≥ 160°.

  4. Optically transparent and environmentally durable superhydrophobic coating based on functionalized SiO2 nanoparticles

    DOE PAGES

    Schaeffer, Daniel A.; Polizos, Georgios; Smith, D. Barton; ...

    2015-01-09

    Optical surfaces such as mirrors and windows that are exposed to outdoor environmental conditions are susceptible to dust buildup and water condensation. The application of transparent superhydrophobic coatings on optical surfaces can improve outdoor performance via a self-cleaning effect similar to the Lotus effect. The contact angle (CA) of water droplets on a typical hydrophobic flat surface varies from 100° to 120°. Adding roughness or microtexture to a hydrophobic surface leads to an enhancement of hydrophobicity and the CA can be increased to a value in the range of 16≥0° to 175°. This result is remarkable because such behavior cannotmore » be explained using surface chemistry alone. When surface features are on the order of 100 nm or smaller, surfaces exhibit superhydrophobic behavior and maintain their optical transparency. In this work we discuss our results on transparent superhydrophobic coatings that can be applied across large surface areas. We have used functionalized silica nanoparticles to coat various optical elements and have measured the contact angle and optical transmission between 190 to 1100 nm on these elements. The functionalized silica nanoparticles were dissolved in a solution of the solvents isopropyl alcohol and 4-chlorobenzotrifluoride (PCBTF) and a proprietary ceramic binder (Cerakote ). Finally, this solution was spin-coated onto a variety of test glass substrates, and following a curing period of about 30 minutes, these coatings exhibited superhydrophobic behavior with a static CA ≥160°.« less

  5. Sulfurization effect on optical properties of Cu2SNS3 thin films grown by two-stage process

    NASA Astrophysics Data System (ADS)

    Reddy, G. Phaneendra; Reddy, K. T. Ramakrishna

    2017-05-01

    A good phase controlled and impurity free two stage process was used to prepare Cu2SnS3 layers on glass substrates. The layers were prepared by sulfurization of sputtered Cu-Sn metallic precursors by varying the sulfurization temperature (Ts) in the range, 150-450°C, keeping the other deposition parameters constant. A complete investigation of the optical properties of the layers with sulfurization temperature was made by using the optical transmittance and reflectance measurements versus wavelength. The absorption coefficient α, was evaluated using the optical data that showed a α > 104 cm-1 for all the as-grown films. The optical bandgap of the as grown layers was determined from the second derivative diffused reflectance spectra that varied from 1.96 eV to 0.99 eV. Consequently, refractive index and extinction coefficient were calculated from Pankov's relations. In addition, the other optical parameters such as the dielectric constants, dissipation factor and also optical conductivity calculated. A detailed analysis of the dependence of all the above parameters on Ts is reported and discussed.

  6. Anisotropy of the optical and magneto-optical response of Au/Co/Au/Cu multilayers grown on vicinal Si (111) surfaces

    NASA Astrophysics Data System (ADS)

    Cheikh-Rouhou, W.; Sampaio, L. C.; Bartenlian, B.; Beauvillain, P.; Brun, A.; Ferré, J.; Georges, P.; Jamet, J.-P.; Mathet, V.; Stupakewicz, A.

    2002-05-01

    The optical and magneto-optical second harmonic reflectivity response of Au/Co/Au/Cu multilayers grown on vicinal Si (111) substrates has been studied. These azimuthal optical non-linear experiments check the uniaxial character of the crystallinity of the Au buffer layer and the magnetic behavior of the ultrathin Co films in the metallic multilayer. They clearly show the strong dependence of the growth parameters and the misorientation of the vicinal surface on the SHG reflectivity signals. This uniaxial behavior is also correlated to linear MOKE experiments on the magnetic anisotropy with an easy magnetization axis parallel to the step edges.

  7. Growth and optical properties of AlN homoepitaxial layers grown by ammonia-source molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Iwata, Shiro; Nanjo, Yoshiyuki; Okuno, Toshihiro; Kurai, Satoshi; Taguchi, Tsunemasa

    2007-04-01

    We have performed the homoepitaxial growth of high-crystalline quality Aluminium nitride (AlN) epilayers by the ammonia-gas source (GS) molecular-beam epitaxy method using the hydride vapor-phase epitaxy (HVPE) grown AlN thin layers as substrates. Surface morphologies and step-bunching structures of the homoepitaxially grown AlN epilayers were evaluated using in situ reflection high-energy electron diffraction (RHEED) patterns and scanning probe microscopy. It is noted that the step height of several monolayers was achieved on the surface of homoepitaxial layers. The homoepitaxial AlN thin films had the same or improved crystalline quality compared with the HVPE-grown AlN layers from X-ray rocking curve measurements, and its optical properties were investigated using cathodoluminescence measurements. Excitonic emission, which originates from the A free-exciton transition, was clearly observed in the present high-quality homoepitaxial AlN epilayers.

  8. Solar energy absorption characteristics and the effects of heat on the optical properties of several coatings

    NASA Technical Reports Server (NTRS)

    Lowery, J. R.

    1981-01-01

    The solar energy absorption characteristics of several high temperature coatings were determined and effects of heat on these coatings were evaluated. Included in the investigation were an electroplated alloy of black chrome and vanadium, electroplated black chrome, and chemically colored 316 stainless steel. Each of the coatings possessed good selective solar energy absorption properties at laboratory ambient temperature. Measured at a temperature of 700 K (800 F), the emittances of black chrome, black chrome vanadium, and colored stainless steel were 0.11, 0.61, and 0.15, respectively. Black chrome and black chrome vanadium did not degrade optically in the presence of high heat (811 K (1000 F)). Chemically colored stainless steel showed slight optical degradation when exposed to moderately high heat (616 K (650 F)0, but showed more severe degradation at exposure temperatures beyond this level. Each of the coatings showed good corrosion resistance to a salt spray environment.

  9. Tapered optical fiber coated with graphene based nanomaterials for measurement of ethanol concentrations in water

    NASA Astrophysics Data System (ADS)

    Girei, Saad H.; Shabaneh, Atafat A.; Ngee-Lim, Hong; Hamidon, Mohd N.; Mahdi, Mohd A.; Yaacob, Mohd H.

    2015-06-01

    Tapered optical fibers coated with graphene and graphene oxide (GO) as the active layer for ethanol sensing were reported. The multimode optical fiber with 125 µm diameter was tapered to 40 µm diameter to enhance the sensitivity. Graphene and GO thin films were characterized using a scanning electron microscopy, Raman spectroscopy and ultraviolet-visible (UV-Vis) spectroscopy. The absorbance properties of the developed sensors increased when exposed to ethanol due to the change of light in the evanescent field. The sensing results indicated that the GO-coated sensor showed better performance with absorbance change of 80 % towards ethanol concentration of 5 % when compared to graphene-coated sensor with 40 % absorbance change towards ethanol with similar concentrations. The reliable response of the graphene and GO-coated on tapered fibers for detecting ethanol concentrations was achieved at room temperature.

  10. Computational manufacturing of optical interference coatings: method, simulation results, and comparison with experiment.

    PubMed

    Friedrich, Karen; Wilbrandt, Steffen; Stenzel, Olaf; Kaiser, Norbert; Hoffmann, Karl Heinz

    2010-06-01

    Virtual deposition runs have been performed to estimate the production yield of selected oxide optical interference coatings when plasma ion-assisted deposition with an advanced plasma source is applied. Thereby, deposition of each layer can be terminated either by broadband optical monitoring or quartz crystal monitoring. Numerous deposition runs of single-layer coatings have been performed to investigate the reproducibility of coating properties and to quantify deposition errors for the simulation. Variations of the following parameters are considered in the simulation: refractive index, extinction coefficient, and film thickness. The refractive index and the extinction coefficient are simulated in terms of the oscillator model. The parameters are varied using an apodized normal distribution with known mean value and standard deviation. Simulation of variations in the film thickness is performed specific to the selected monitoring strategy. Several deposition runs of the selected oxide interference coatings have been performed to verify the simulation results by experimental data.

  11. Quantifying Pharmaceutical Film Coating with Optical Coherence Tomography and Terahertz Pulsed Imaging: An Evaluation

    PubMed Central

    Lin, Hungyen; Dong, Yue; Shen, Yaochun; Zeitler, J Axel

    2015-01-01

    Spectral domain optical coherence tomography (OCT) has recently attracted a lot of interest in the pharmaceutical industry as a fast and non-destructive modality for quantification of thin film coatings that cannot easily be resolved with other techniques. Because of the relative infancy of this technique, much of the research to date has focused on developing the in-line measurement technique for assessing film coating thickness. To better assess OCT for pharmaceutical coating quantification, this paper evaluates tablets with a range of film coating thickness measured using OCT and terahertz pulsed imaging (TPI) in an off-line setting. In order to facilitate automated coating quantification for film coating thickness in the range of 30–200 μm, an algorithm that uses wavelet denoising and a tailored peak finding method is proposed to analyse each of the acquired A-scan. Results obtained from running the algorithm reveal an increasing disparity between the TPI and OCT measured intra-tablet variability when film coating thickness exceeds 100 μm. The finding further confirms that OCT is a suitable modality for characterising pharmaceutical dosage forms with thin film coatings, whereas TPI is well suited for thick coatings. © 2015 The Authors. Journal of Pharmaceutical Sciences published by Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3377–3385, 2015 PMID:26284354

  12. Quantifying Pharmaceutical Film Coating with Optical Coherence Tomography and Terahertz Pulsed Imaging: An Evaluation.

    PubMed

    Lin, Hungyen; Dong, Yue; Shen, Yaochun; Zeitler, J Axel

    2015-10-01

    Spectral domain optical coherence tomography (OCT) has recently attracted a lot of interest in the pharmaceutical industry as a fast and non-destructive modality for quantification of thin film coatings that cannot easily be resolved with other techniques. Because of the relative infancy of this technique, much of the research to date has focused on developing the in-line measurement technique for assessing film coating thickness. To better assess OCT for pharmaceutical coating quantification, this paper evaluates tablets with a range of film coating thickness measured using OCT and terahertz pulsed imaging (TPI) in an off-line setting. In order to facilitate automated coating quantification for film coating thickness in the range of 30-200 μm, an algorithm that uses wavelet denoising and a tailored peak finding method is proposed to analyse each of the acquired A-scan. Results obtained from running the algorithm reveal an increasing disparity between the TPI and OCT measured intra-tablet variability when film coating thickness exceeds 100 μm. The finding further confirms that OCT is a suitable modality for characterising pharmaceutical dosage forms with thin film coatings, whereas TPI is well suited for thick coatings.

  13. Quantifying Pharmaceutical Film Coating with Optical Coherence Tomography and Terahertz Pulsed Imaging: An Evaluation.

    PubMed

    Lin, Hungyen; Dong, Yue; Shen, Yaochun; Axel Zeitler, J

    2015-10-01

    Spectral domain optical coherence tomography (OCT) has recently attracted a lot of interest in the pharmaceutical industry as a fast and non-destructive modality for quantification of thin film coatings that cannot easily be resolved with other techniques. Because of the relative infancy of this technique, much of the research to date has focused on developing the in-line measurement technique for assessing film coating thickness. To better assess OCT for pharmaceutical coating quantification, this paper evaluates tablets with a range of film coating thickness measured using OCT and terahertz pulsed imaging (TPI) in an off-line setting. In order to facilitate automated coating quantification for film coating thickness in the range of 30-200μm, an algorithm that uses wavelet denoising and a tailored peak finding method is proposed to analyse each of the acquired A-scan. Results obtained from running the algorithm reveal an increasing disparity between the TPI and OCT measured intra-tablet variability when film coating thickness exceeds 100μm. The finding further confirms that OCT is a suitable modality for characterising pharmaceutical dosage forms with thin film coatings, whereas TPI is well suited for thick coatings. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3377-3385, 2015. Copyright © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  14. In-Line Monitoring of a Pharmaceutical Pan Coating Process by Optical Coherence Tomography.

    PubMed

    Markl, Daniel; Hannesschläger, Günther; Sacher, Stephan; Leitner, Michael; Buchsbaum, Andreas; Pescod, Russel; Baele, Thomas; Khinast, Johannes G

    2015-08-01

    This work demonstrates a new in-line measurement technique for monitoring the coating growth of randomly moving tablets in a pan coating process. In-line quality control is performed by an optical coherence tomography (OCT) sensor allowing nondestructive and contact-free acquisition of cross-section images of film coatings in real time. The coating thickness can be determined directly from these OCT images and no chemometric calibration models are required for quantification. Coating thickness measurements are extracted from the images by a fully automated algorithm. Results of the in-line measurements are validated using off-line OCT images, thickness calculations from tablet dimension measurements, and weight gain measurements. Validation measurements are performed on sample tablets periodically removed from the process during production. Reproducibility of the results is demonstrated by three batches produced under the same process conditions. OCT enables a multiple direct measurement of the coating thickness on individual tablets rather than providing the average coating thickness of a large number of tablets. This gives substantially more information about the coating quality, that is, intra- and intertablet coating variability, than standard quality control methods. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  15. X-ray reflection efficiency of nickel-coated quartz optical flats

    NASA Technical Reports Server (NTRS)

    Reynolds, J. M.; Fields, S. A.; Wilson, R. M.

    1973-01-01

    The reflection efficiency of quartz optical flats vacuum coated with 1000-A nickel was evaluated. Of the three vacuum coated samples tested, two had been contaminated during the firing of the Lunar Module Reaction Control System in the vacuum chamber. Measurements were made for 1.54-, 1.79-, and 2.29-A incident radiation. The reflection efficiency of the contaminated samples was reduced by as much as 50 percent for some angles of incidence.

  16. Wideband optical coatings for protecting artwork from ultraviolet and infrared radiation damage

    NASA Astrophysics Data System (ADS)

    Piegari, Angela; Polato, Pietro

    2003-09-01

    The damaging effects of illumination on artwork are well known. Art conservation requires protection from both vandalism and radiation damage. Glass is an appropriate material for these requirements but it partially transmits UV and IR radiation. An optical coating on glass that eliminates UV and IR radiation coming from natural or artificial illumination, is proposed. This coated glass, positioned in front of the artwork, is also able to reduce reflection without altering the appearance or colour.

  17. Combined laser calorimetry and photothermal technique for absorption measurement of optical coatings

    SciTech Connect

    Li Bincheng; Blaschke, Holger; Ristau, Detlev

    2006-08-10

    To the best of our knowledge, a combined sensitive technique employing both laser calorimetry and a surface thermal lens scheme for measuring absorption values of optical coatings is presented for the first time. Laser calorimetric and pulsed surface thermal lens signals are simultaneously obtained with a highly reflecting UV coating sample irradiated at 193 nm. The advantages and potential applications of the combined technique and the experimental factors limiting the measurement sensitivity are discussed.

  18. Combined laser calorimetry and photothermal technique for absorption measurement of optical coatings.

    PubMed

    Li, Bincheng; Blaschke, Holger; Ristau, Detlev

    2006-08-10

    To the best of our knowledge, a combined sensitive technique employing both laser calorimetry and a surface thermal lens scheme for measuring absorption values of optical coatings is presented for the first time. Laser calorimetric and pulsed surface thermal lens signals are simultaneously obtained with a highly reflecting UV coating sample irradiated at 193 nm. The advantages and potential applications of the combined technique and the experimental factors limiting the measurement sensitivity are discussed.

  19. Multilayer coatings for optics in the extreme ultraviolet

    NASA Astrophysics Data System (ADS)

    Larruquert, Juan I.; Vidal-Dasilva, Manuela; García-Cortés, Sergio; Rodríguez-de Marcos, Luis; Fernández-Perea, Mónica; Aznárez, José A.; Méndez, José A.

    2011-02-01

    The strong absorption of materials in the extreme ultraviolet (EUV) above ~50 nm has precluded the development of efficient coatings. The development of novel coatings with improved EUV performance is presented. An extensive research was performed on the search and characterization of new materials with low absorption or high reflectance. Lanthanide series was found to be a source of materials with relatively low absorption in this range, where most materials in nature present a strong absorption. Other materials, such as SiO and B, have been found to have interesting properties for applications on EUV coatings. As a result, novel multilayers based on Yb, Al, and SiO have been developed with narrowband performance in the 50-92 nm range. In some cases, the difficulty of developing narrowband coatings in the EUV can be overcome by designing multilayers that address specific purposes, such as maximizing and/or minimizing the reflectance at two or more wavelengths or bands. In this direction, we are working towards the development of coatings that combine a relatively high reflectance in a desired EUV band with a low reflectance in another band, for applications in which the presence of the latter radiation may mask a weak EUV radiation source.

  20. Structural and optical properties of near-UV LEDs grown on V-grooved sapphire substrates fabricated by wet etching

    NASA Astrophysics Data System (ADS)

    Cheong, H. S.; Na, M. G.; Choi, Y. J.; Cuong, T. V.; Hong, C.-H.; Suh, E.-K.; Kong, B. H.; Cho, H. K.

    2007-01-01

    V-grooved sapphire substrates (VGSS) were fabricated by a simple wet etching process with SiO 2 stripe masks along < 1 1¯ 2 0> orientation of the sapphire substrate and a mixed solution of H 2SO 4 and H 3PO 4. The growth of low-defect GaN template was optimized by two-step growth technique of metalorganic vapor deposition (MOCVD), resulting in the threading dislocation (TD) density of 2-4×10 7 cm -2 in the entire region of the GaN template. The epitaxial structure of near-UV light emitting diode (LED) was grown on the GaN templates on both the VGSS and the flat sapphire substrate (FSS) in order to compare the characteristics of their structural and optical properties. The internal quantum efficiency and the extraction efficiency of the LED structure grown on the VGSS were remarkably increased when compared to the conventional LED structure grown on the FSS. It seems to be attributed to the reduction in the TD density of the GaN template on the VGSS and the decrease in the number of times of total internal reflections of the light flux due to the V-grooved pattern, respectively. The increase in optical output power of the LED grown on the VGSS agreed well with the expected value based on the simulation of the commercial Light Tool program and temperature-dependent photoluminescence (PL) intensities.

  1. Optical properties of as-grown and annealed InAs(N)/InGaAsP strained multiple quantum wells

    NASA Astrophysics Data System (ADS)

    Chen, Guan-Ru; Lin, Hao-Hsiung; Wang, Jyh-Shyang; Shih, Ding-Kang

    2001-12-01

    Optical and structural properties of as-grown and annealed InAs(N)/InGaAsP strained multiple quantum-well (MQW) structures grown by gas source molecular-beam epitaxy are investigated by photoluminescence (PL), double crystal x-ray diffraction, and photoconductivity spectroscopies. Properties of the as-grown and annealed MQW's are studied and those of the InAs/InGaAsP MQW (C821) and the InAsN/InGaAsP MQW with the lowest nitrogen contents N=1.1% in the well (C822) are compared. For the C821 InAs/InGaAsP MQW with a very large total strain, a low energy shoulder, possibly induced by defects or impurities, can be seen in the low temperature PL spectrum, and a large density of nonradiative recombination centers is found. For nitrogen-containing MQW's, the PL full width at half maximum and PL peak evolutions with increasing annealing temperature are influenced by the alloy inhomogeneities. The initial redshift of the PL peak after rapid thermal annealing means that the luminescence is dominated by As-rich regions in these as-grown samples. Exciton localization induced by alloy disorders is also found in high-nitrogen-content samples. By comparing the experimental results of C821 and C822, adding a little nitrogen to reduce the rather large total strain in the structure is beneficial to structural and optical quality improvement.

  2. Audio-band coating thermal noise measurement for Advanced LIGO with a multimode optical resonator

    NASA Astrophysics Data System (ADS)

    Gras, S.; Yu, H.; Yam, W.; Martynov, D.; Evans, M.

    2017-01-01

    In modern high precision optical instruments, such as in gravitational wave detectors or frequency references, thermally induced fluctuations in the reflective coatings can be a limiting noise source. This noise, known as coating thermal noise, can be reduced by choosing materials with low mechanical loss. Examination of new materials becomes a necessity in order to further minimize the coating thermal noise and thus improve sensitivity of next generation instruments. We present a novel approach to directly measure coating thermal noise using a high finesse folded cavity in which multiple Hermite-Gaussian modes coresonate. This method is used to probe surface fluctuations on the order 10-17 m /√{Hz } in the frequency range 30-400 Hz. We applied this technique to measure thermal noise and loss angle of the coating used in Advanced LIGO.

  3. Design of antireflective nanostructures and optical coatings for next-generation multijunction photovoltaic devices.

    PubMed

    Perl, Emmett E; McMahon, William E; Bowers, John E; Friedman, Daniel J

    2014-08-25

    The successful development of multijunction photovoltaic devices with four or more subcells has placed additional importance on the design of high-quality broadband antireflection coatings. Antireflective nanostructures have shown promise for reducing reflection loss compared to the best thin-film interference coatings. However, material constraints make nanostructures difficult to integrate without introducing additional absorption or electrical losses. In this work, we compare the performance of various nanostructure configurations with that of an optimized multilayer antireflection coating. Transmission into a four-junction solar cell is computed for each antireflective design, and the corresponding cell efficiency is calculated. We find that the best performance is achieved with a hybrid configuration that combines nanostructures with a multilayer thin-film optical coating. This approach increases transmitted power into the top subcell by 1.3% over an optimal thin-film coating, corresponding to an increase of approximately 0.8% in the modeled cell efficiency.

  4. J-Black: a stray light coating for optical and infrared systems

    NASA Astrophysics Data System (ADS)

    Waddell, Patrick; Black, David S.

    2016-07-01

    A new stray light coating, called J-Black, has been developed for NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA). The coating is a layered composition of Nextel-Suede 3101 primers and top coats and silicon carbide grit. J-Black has been applied to large areas of the SOFIA airborne telescope and is currently operating within the open cavity environment of the Boeing 747. Over a series of discrete filter bands, from 0.4 to 21 microns, J-Black optical and infrared reflectivity performance is compared with other available coatings. Measured total reflectance values are less than 2% at the longest wavelengths, including at high incidence angles. Detailed surface structure characteristics are also compared via electron and ion microscopy. Environmental tests applicable for aerospace applications are presented, as well as the detailed steps required to apply the coating.

  5. Numerical methods for the design of gradient-index optical coatings.

    PubMed

    Anzengruber, Stephan W; Klann, Esther; Ramlau, Ronny; Tonova, Diana

    2012-12-01

    We formulate the problem of designing gradient-index optical coatings as the task of solving a system of operator equations. We use iterative numerical procedures known from the theory of inverse problems to solve it with respect to the coating refractive index profile and thickness. The mathematical derivations necessary for the application of the procedures are presented, and different numerical methods (Landweber, Newton, and Gauss-Newton methods, Tikhonov minimization with surrogate functionals) are implemented. Procedures for the transformation of the gradient coating designs into quasi-gradient ones (i.e., multilayer stacks of homogeneous layers with different refractive indices) are also developed. The design algorithms work with physically available coating materials that could be produced with the modern coating technologies.

  6. Zirconia-coated carbonyl-iron-particle-based magnetorheological fluid for polishing optical glasses and ceramics

    SciTech Connect

    Shafrir, Shai N.; Romanofsky, Henry J.; Skarlinski, Michael; Wang, Mimi; Miao, Chunlin; Salzman, Sivan; Chartier, Taylor; Mici, Joni; Lambropoulos, John C.; Shen Rui; Yang Hong; Jacobs, Stephen D.

    2009-12-10

    We report on magnetorheological finishing (MRF) spotting experiments performed on glasses and ceramics using a zirconia-coated carbonyl-iron (CI)-particle-based magnetorheological (MR) fluid. The zirconia-coated magnetic CI particles were prepared via sol-gel synthesis in kilogram quantities. The coating layer was {approx}50-100 nm thick, faceted in surface structure, and well adhered. Coated particles showed long-term stability against aqueous corrosion. ''Free'' nanocrystalline zirconia polishing abrasives were cogenerated in the coating process, resulting in an abrasive-charged powder for MRF. A viable MR fluid was prepared simply by adding water. Spot polishing tests were performed on a variety of optical glasses and ceramics over a period of nearly three weeks with no signs of MR fluid degradation or corrosion. Stable material removal rates and smooth surfaces inside spots were obtained.

  7. Stimulated emission and optical gain in AlGaN heterostructures grown on bulk AlN substrates

    SciTech Connect

    Guo, Wei Bryan, Zachary; Kirste, Ronny; Bryan, Isaac; Hussey, Lindsay; Bobea, Milena; Haidet, Brian; Collazo, Ramón; Sitar, Zlatko; Xie, Jinqiao; Mita, Seiji; Gerhold, Michael

    2014-03-14

    Optical gain spectra for ∼250 nm stimulated emission were compared in three different AlGaN-based structures grown on single crystalline AlN substrates: a single AlGaN film, a double heterostructure (DH), and a Multiple Quantum Well (MQW) structure; respective threshold pumping power densities of 700, 250, and 150 kW/cm{sup 2} were observed. Above threshold, the emission was transverse-electric polarized and as narrow as 1.8 nm without a cavity. The DH and MQW structures showed gain values of 50–60 cm{sup −1} when pumped at 1 MW/cm{sup 2}. The results demonstrated the excellent optical quality of the AlGaN-based heterostructures grown on AlN substrates and their potential for realizing electrically pumped sub-280 nm laser diodes.

  8. Resonances in coated long period fiber gratings and cladding removed multimode optical fibers: a comparative study.

    PubMed

    Del Villar, Ignacio; Zamarreño, Carlos R; Hernaez, Miguel; Arregui, Francisco J; Matias, Ignacio R

    2010-09-13

    Two optical fiber devices have been coated in parallel: a long period fiber grating (LPFG) and a cladding-removed multimode optical fiber (CRMOF). The progressive coating of the LPFG by means of the layer-by-layer electrostatic-self-assembly, permits to observe a resonance wavelength shift of the attenuation bands in the transmission spectrum. The cause of this wavelength shift is the reorganization of the cladding mode effective indices. The cause of this modal reorganization can be understood with the results observed in the CRMOF coated in parallel. A lossy-mode-resonance (LMR) is generated in the same wavelength range of the LPFG attenuation bands analyzed. Moreover, the thickness range where the wavelength shift of the LPFG attenuation bands occurs coincides exactly with the thickness range where the LMR can be visualized in the transmission spectrum. These phenomena are analyzed theoretically and corroborated experimentally. The advantages and disadvantages of both optical fiber devices are explained.

  9. Aluminum Mirror Coatings for UVOIR Telescope Optics Including the Far UV

    NASA Technical Reports Server (NTRS)

    Balasubramanian, Kunjithapatha; Hennessy, John; Raouf, Nasrat; Nikzad, Shouleh; Ayala, Michael; Shaklan, Stuart; Scowen, Paul; Del Hoyo, Javier; Quijada, Manuel

    2015-01-01

    NASA Cosmic Origins (COR) Program identified the development of high reflectivity mirror coatings for large astronomical telescopes particularly for the far ultra violet (FUV) part of the spectrum as a key technology requiring significant materials research and process development. In this paper we describe the challenges and accomplishments in producing stable high reflectance aluminum mirror coatings with conventional evaporation and advanced Atomic Layer Deposition (ALD) techniques. We present the current status of process development with reflectance of approx. 55 to 80% in the FUV achieved with little or no degradation over a year. Keywords: Large telescope optics, Aluminum mirror, far UV astrophysics, ALD, coating technology development.

  10. Characterization of optical coatings using a multisource table-top scatterometer.

    PubMed

    von Finck, Alexander; Herffurth, Tobias; Schröder, Sven; Duparré, Angela; Sinzinger, Stefan

    2014-02-01

    Light scattering measurement and analysis is a powerful tool for the characterization of optical and nonoptical surfaces. To enable a more comprehensive postmeasurement characterization, three visible laser sources were recently implemented in a highly sensitive table-top scatterometer with 3D spherical detection capability. Based on wavelength scaling, the instrument is utilized to characterize thin-film coatings and their substrates with respect to surface roughness, roughness growth, and contamination. Topographic measurement techniques are used to verify the results. The spectral sensitivity to contamination (scatter loss) is demonstrated to be significantly different for single surfaces and interference coatings. In addition, power losses of a highly reflective coating are analyzed.

  11. Study on Thermochromic VO2 Films Grown on ZnO-Coated Glass Substrates for “Smart Windows”

    NASA Astrophysics Data System (ADS)

    Kato, Kazuhiro; Song, Pung Keun; Odaka, Hidehumi; Shigesato, Yuzo

    2003-10-01

    Vanadium dioxide (VO2) is one of the most attractive thermochromic materials, which show large changes in optical and electrical properties at the transition temperature (Tt) close to the atmospheric temperature (approximately 340 K). We already reported for VO2 deposition by rf magnetron sputtering using V2O3 or V2O5 targets that VO2 films thicker than 400 nm showed high thermochromic performance, whereas the VO2 films thinner than 200 nm did not show such performance because of their poor crystallinity and off-stoichiometry. In this study, very thin thermochromic VO2 films with thicknesses of about 50 nm were successfully deposited using highly < 001>-preferred oriented ZnO polycrystalline films as a buffer layer between the VO2 film and glass substrate (VO2/ZnO/glass) because of the heteroepitaxial growth of VO2 polycrystalline films. W-doped VO2 films were also deposited on the ZnO-coated glass substrates (ZnO/glass) by cosputtering. It was confirmed that W doping for thin VO2 films deposited on the ZnO/glass can decrease Tt systematically. Such very thin VO2 films should have high potential for application in “smart windows”.

  12. Development of surface thermal lensing technique in absorption and defect analyses of optical coatings

    NASA Astrophysics Data System (ADS)

    He, Hongbo; Li, Xia; Fan, Shuhai; Shao, Jianda; Zhao, Yuanan; Fan, Zhengxiu

    2005-12-01

    Absorption is one of the main factors which cause damage to optical coatings, under the radiation of high power lasers. Surface thermal lensing (STL) technique was developed into a practical high-sensitivity apparatus for the weak absorption analysis of optical coatings. A 20 W continuous-wave 1064 nm Nd:YAG laser and a 30 mW He-Ne laser were employed as pump source and probe source, respectively. Low noise photoelectrical components and an SR830 DSP lock-in amplifier were used for photo-thermal deformation signal detection. In order to improve sensitivity, the configuration of the apparatus was optimized through choosing appropriate parameters, that including pump beam spot size, chopper frequency, detection distance, waist radius and position of probe beam. Coating samples were mounted on an x-y stage which was driven by high precision stepper motors. Different processes of absorption measurements, including single spot, linear scan and 2-dimension area scan, could be performed manually or automatically under the control of PC program. Various optical coatings were prepared by both electron beam evaporation and ion beam sputtering deposition. High sensitivity was obtained and low to 10 ppb absorption could be measured by surface thermal lensing technique. And a spatial resolution of 25 micron was proved according to the area scanning which traced out the profile of photo-thermal defects inside optical coatings. The system was employed in the analyses of optical absorption, absorption uniformity and defect distribution, and revealed the relationship between laser-induced damage and absorption of optical coatings.

  13. Structure of anodized Al-Zr sputter deposited coatings and effect on optical appearance

    NASA Astrophysics Data System (ADS)

    Gudla, Visweswara Chakravarthy; Canulescu, Stela; Shabadi, Rajashekhara; Rechendorff, Kristian; Dirscherl, Kai; Ambat, Rajan

    2014-10-01

    The mechanism of interaction of light with the microstructure of anodized layer giving specific optical appearance is investigated using Al-Zr sputter deposited coating as a model system on an AA6060 substrate. Differences in the oxidative nature of various microstructural components result in the evolution of typical features in the anodized layer, which are investigated as a function of microstructure and correlated with its optical appearance. The Zr concentration in the coating was varied from 6 wt.% to 23 wt.%. Heat treatment of the coated samples was carried out at 550 °C for 4 h in order to evolve Al-Zr based second phase precipitates in the microstructure. Anodizing was performed using 20 wt.% sulphuric acid at 18 °C with an intention to study the effect of anodizing on the Al-Zr based precipitates in the coating. Detailed microstructural characterization of the coating and anodized layer was carried out using high resolution scanning and transmission electron microscopy, grazing incidence X-ray diffraction analysis, glow discharge optical emission spectroscopy, and optical appearance using spectrophotometry. The evolution of microstructure in the anodized layer as a function of anodizing parameters and their influence on the interaction of light is investigated and the results in general are applicable to discolouration of anodized layer on recycled aluminium alloys due to intermetallics.

  14. Highly sensitive fiber optic Fabry-Perot geophone with graphene coated PMMA membrane

    NASA Astrophysics Data System (ADS)

    Yu, C. B.; Wu, Y.; Wu, F.; Li, C.; Zhou, J. H.; Rao, Y. J.; Chen, Y. F.

    2017-04-01

    A highly sensitive fiber-optic Fabry-Perot interferometric geophone (FFPG) with graphene coated PMMA membrane is proposed and demonstrated, where the graphene coating is used for enhancement of the mechanical strength of the membrane. It is found that the sensitivity of the FFPG is much higher than that of the conventional electrical geophone. Such a novel all-optical geophone with low cost, high sensitivity, electromagnetic interference immunity, easy fabrication and robust structure would have great potential for use in oil/gas exploration and seismic wave detection.

  15. High-sensitivity DNA biosensor based on optical fiber taper interferometer coated with conjugated polymer tentacle.

    PubMed

    Huang, Yunyun; Tian, Zhuang; Sun, Li-Peng; Sun, Dandan; Li, Jie; Ran, Yang; Guan, Bai-Ou

    2015-10-19

    A sensitive bio-probe to in situ detect unlabeled single-stranded DNA targets based on optical microfiber taper interferometer coated by a high ordered pore arrays conjugated polymer has been presented. The polymer coating serves as tentacles to catch single-stranded DNA molecules by π-π conjugated interaction and varies the surface refractive index of the optical microfiber. The microfiber taper interferometer translates the refractive index information into wavelength shift of the interference fringe. The sensor exhibits DNA concentration sensitivity of 2.393 nm/log M and the lowest detection ability of 10(-10) M or even lower.

  16. 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.

  17. Development and characterization of coatings on silicon pore optics substrates for the ATHENA Mission

    NASA Astrophysics Data System (ADS)

    Ferreira, Desiree Della Monica; Jakobsen, Anders C.; Christensen, Finn E.; Shortt, Brian J.; Krumrey, Michael; Garnæs, Jørgen; Simonsen, Ronni B.

    2012-09-01

    We present description and results of the test campaign performed on Silicon Pore Optics (SPO) samples to be used on the ATHENA mission. We perform a pre-coating characterization of the substrates using Atomic Force Microscopy (AFM), X-ray Re ectometry (XRR) and scatter measurements. X-ray tests at DTU Space and correlation between measured roughness and pre-coating characterization are reported. For coating development, a layer of Cr was applied underneath the Ir/B4C bi-layer with the goal of reducing stress, and the use of N2 during the coating process was tested in order to reduce the surface roughness in the coatings. Both processes show promising results. Measurements of the coatings were carried out at the 8 keV X-ray facility at DTU Space and with synchrotron radiation in the laboratory of PTB at BESSY II to determine re ectivity at the grazing incidence angles and energies of ATHENA. Coating development also included a W/Si multilayer coating. We present preliminary results on X-ray Re ectometry and Cross-sectional Transmission Electron Microscopy (TEM) of the W/Si multilayer.

  18. Advanced optical coating technology used in the development of concentrator arrays for solar space power applications

    NASA Astrophysics Data System (ADS)

    Fulton, Michael L.; O'Neill, Mark J.

    2006-08-01

    Since 1990 thin film optical coatings have taken a prominent role in the development of highly efficient solar power concentrators for future space applications. During the initial development of this coating technology, the Boeing High Technology Center explored various ways of protecting ENTECH's DC93-500 silicone Fresnel lenses from the harsh space environment. ENTECH's mini-dome lenses focused solar energy onto small high-efficiency solar cells for generating electrical power. To protect the silicone lenses from solar UV darkening, one early approach involved a cerium-doped glass cover cemented over the lens. Unfortunately, during launch simulation shock testing the glass lens covers cracked. We next explored the deposition of a UV blocking thin film coating directly to the silicone lens surface. This was a problem of immense proportions analogous to pouring concrete on to the surface of a reservoir filled with "Jell-O." Differential in coefficient of thermal expansion between the DC93-500 silicone and the deposited dielectric optical coating had to be balanced with intrinsic stress of the optical coating materials. Ion Beam Optics' work has culminated, some fifteen years later, in the current coating technology that is being incorporated in the Stretched Lens Array SquareRigger (SLASR). SLASR is designed to replace classic flat panel solar arrays with a lighter, lower cost, and more efficient (30%) concentrator arrays for future space applications. This paper will describe the coating technology and show its performance and benefits for SLASR space power systems. Results from both ground tests and space flight tests will be presented.

  19. Large-area sol-gel optical coatings for the Megajoule Laser prototype

    NASA Astrophysics Data System (ADS)

    Pegon, Philippe M.; Germain, Chantal V.; Rorato, Yannick R.; Belleville, Philippe F.; Lavastre, Eric

    2004-02-01

    In the field of thin film coatings, sol-gel (SG) process is an alternative to the conventional Physical Vapor Deposition (PVD) techniques. Sol-gel process is particularly competitive on large-area or fragile substates by taking advantage of various liquid phase deposition techniques performed at room temperature and atmospheric pressure, coupled with the versatility of organo-metallic chemistry. Developed by the French Commission for Atomic Energy (CEA) since 1985 for its former high-power lasers generation, optimized sol-gel coatings proved also very resistant to laser energy. In 1998, THALES Angenieux (TAGX) was selected by CEA to provide all the sol-gel coatings dedicated to the French Laser MegaJoule (LMJ) prototype, named Ligne d'Integration Laser (LIL). In cooperation with Saint-Etienne Pole Optique et Vision (POV), TAGX initiated the building of a sol-gel technological platform (SGPF) aimed at demonstrating the feasibility of production of optical and functional coatings on large area substrates. A technology transfer was performed by CEA (Le Ripault) to TAGX focusing on the manufacture mainly of single-layer antireflective coatings (SLAR), but also of multi-layer AR-coatings and of multi-layered highly reflective (HR)-coatings. Since beginning of 2001 and using SGPF equipments, TAGX successfully coated within specificaitons and schedule most of the 300 optics required for LIL activation. After this 2 years 1/2 production campaign in pre-industrial conditions, we can now analyse the advantages of each deposition technique used, the repeatability of the several processes, and the performance of the various coatings.

  20. Diode laser 87Rb optical pumping in an evacuated wall-coated cell

    NASA Technical Reports Server (NTRS)

    Lee, W. K.; Robinson, H. G.; Johnson, C. E.

    1984-01-01

    The evacuated wall coated sealed cell coupled with diode laser optical pumping offers a number of attractive potential advantages for use in Rb or Cs atomic frequency standards. An investigation of systematic effects is required to explore possible limitations of the technique. The use of diode laser optical pumping of 87 Rb in an evacuated wall coated sealed cell is presented. Experimental results/discussion to be presented include the signal strength and line broadening of the 0 - 0 hyperfine resonance as a function of light intensity for the D1 optical transitions (F - F prime) - (2 1 prime) and (2 - 2 prime), shift of the 0 - 0 hyperfine frequency as a function of laser intensity and de-tuning from optical resonance, and diode laser frequency stabilization techniques.

  1. Behavior of optical thin-film materials and coatings under proton and gamma irradiation.

    PubMed

    Di Sarcina, Ilaria; Grilli, Maria Luisa; Menchini, Francesca; Piegari, Angela; Scaglione, Salvatore; Sytchkova, Anna; Zola, Danilo

    2014-02-01

    Optical materials and coatings are exposed to the flux of energetic particles when used in either space applications or nuclear energy plants. The study of their behavior in such an environment is important to avoid failure of the optical components during their operation. The optical performance of several thin-film materials ((HfO2, Ta2O5, Nb2O5, TiO2, SiO2) and coatings, under irradiation with high-dose gamma rays (5.8 MGy) and exposure to low-energy (60 keV) protons, has been investigated. Some variations of optical properties have been detected in silicon oxide after irradiation, while the other materials are stable in such conditions.

  2. Integration of an organic photodetector onto a plastic optical fiber by means of spray coating technique.

    PubMed

    Binda, Maddalena; Natali, Dario; Iacchetti, Antonio; Sampietro, Marco

    2013-08-21

    A working prototype of integrated fiber/receiver system for optical data transmission is realized. The prototype is made by directly depositing an organic photodetector onto a plastic optical fiber. For the deposition of the organic layers, spray coating is successfully exploited. Operation over four orders of magnitude range of light intensities as well as photoresponse to pulsed stimulation are demonstrated. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Surface properties of hard protective coatings studied by optical techniques

    NASA Astrophysics Data System (ADS)

    Jaglarz, Janusz; Wolska, N.; Mitura, K.; Duraj, R.; Marszalek, K. W.; El Kouari, Y.

    2016-06-01

    The paper describes optical study of SiC, C and NiC layers deposited on Si substrates by double beam ion sputtering (DBIS) method. The following optical methods: ellipsometry, bidirectional reflection distribution function (BRDF) and total integrated scattering (TIS) studies have been applied. The obtained results allowed us to determine the refractive indices, extinction coefficients and the roughness parameters of DBIS films. Also surface profiles of optical constants determined from scanning ellipsometric measurements have been presented. The power spectral density functions (PSD) of surface roughness for studied samples have been determined. The influence of the deposition technology on film topography has been discussed.

  4. Fabrication, Testing, Coating and Alignment of Fast Segmented Optics

    DTIC Science & Technology

    2006-05-25

    mirror segment, a 100 mm thick Zerodur mirror blank was purchased from Schott. Figure 2 shows the segment and its support for polishing and testing in...Polishing large off-axis segments of fast primary mirrors 2. Testing large segments in an off-axis geometry 3. Alignment of multiple segments of a large... mirror 4. Coatings that reflect high-intensity light without distorting the substrate These technologies are critical because of several unique

  5. Coatings for SiO2 optical fibers

    NASA Astrophysics Data System (ADS)

    Covino-Hrbacek, Josephine

    1993-11-01

    A chemical coating consisting of a mixture of tetraethoxysilane (TEOS), Al(OC4H9)3, LiOH, Ti(OC3H7)4, Zr()2C5H7)4, HNO3 for pH control, and glycerol is introduced which produces an environmentally protective barrier resistant to cracking or crazing to a glass fiber to which it is applied by the SOL-GEL process.

  6. Characterizing environmental effects on visible and UV reflectance of ALD-coated optics

    NASA Astrophysics Data System (ADS)

    Carter, Christian; Moore, Christopher S.; Hennessy, John; Jewell, April D.; Nikzad, Shouleh; France, Kevin

    2016-09-01

    Numerous atomic and molecular transitions that provide important diagnostics for astrophysical research exist in the Lyman-ultraviolet (LUV; 91.2 - 121.6 nm) and far-ultraviolet (FUV; 121.6 - 200 nm) bandpasses. Future astronomy and planetary science missions require the development of mirror coatings with improved reflectance between 90 - 200 nm which maintain optical performance in visible and IR wavelengths (320 - 2000 nm). Towards this end, we have developed an atomic layer deposition (ALD) process for optical coatings to enhance the efficiency of future space observatories. We measured the reflectance from 115-826 nm of sample optics, consisting of silicon wafers coated with lithium fluoride films deposited via ALD. We also measured the reflectance of sample optics stored in various environments, and characterized the effect of storage environment on visible and UV optical performance over week-long time scales. Minimal change in optical performance was observed for wavelengths between 200 and 800 nm, regardless of storage environment.

  7. Athermal compensation of the stress-induced surface deflection of optical coatings using iso-admittance layers.

    PubMed

    Lemarquis, Frédéric

    2014-02-01

    Mechanical stress in optical thin films can induce surface deflection of optical coatings. In the case of a substrate coated on both sides, a method is proposed which can provide perfect cancellation of this deflection, independently of the deposition process or any other external parameter, such as the temperature sensitivity of the mechanical stress. It is straightforward to implement this method, based on iso-admittance layers, since the thickness of such layers can be used to freely compensate for deflection effects only, without having any influence on the film's optical properties. This method is illustrated by two possible solutions for the design problem B from the Optical Interference Coatings (OIC) 2013 meeting.

  8. Influence of lithium coating on the optics of Doppler backscatter system.

    PubMed

    Zhang, X H; Liu, A D; Zhou, C; Hu, J Q; Wang, M Y; Yu, C X; Liu, W D; Li, H; Lan, T; Xie, J L

    2015-10-01

    This paper presents the first investigation of the effect of lithium coating on the optics of Doppler backscattering. A liquid lithium limiter has been applied in the Experimental Advanced Superconducting Tokamak (EAST), and a Doppler backscattering has been installed in the EAST. A parabolic mirror and a flat mirror located in the vacuum vessel are polluted by lithium. An identical optical system of the Doppler backscattering is set up in laboratory. The power distributions of the emission beam after the two mirrors with and without lithium coating (cleaned before and after), are measured at three different distances under four incident frequencies. The results demonstrate that the influence of the lithium coating on the power distributions are very slight, and the Doppler backscattering can work normally under the dosage of lithium during the 2014 EAST campaign.

  9. Evaluation of diamond coatings on optical fibre sensors for biological use.

    PubMed

    Neto, V F; Santos, J A; Alberto, N J; Pinto, J L; Nogueira, R N; Grácio, J

    2011-06-01

    The inscription of a Fibre Bragg Grating (FBG) in optical fibres allows them to be used as sensors, being capable of decoding small variations of strain; temperature; pressure; loading; bending; or even refractive index, by means of a shift in the reflected wavelength. Nevertheless, broadening their sensitivity and operation range would be desirable. This may be achieved by appropriated fibre coating. Diamond possesses a set of extreme properties, such as high thermal conductivity, hardness and resistance to hazard environments. Furthermore, it is known for its excellent biocompatible response, so it may be suitable to be used as a coating material for biological sensors. In this paper, the results of the optimization process of diamond coatings on optical fibre sensors is presented, considering their potential use for practical biological purposes.

  10. Optical coherence tomography complemented by hyperspectral imaging for the study of protective wood coatings

    NASA Astrophysics Data System (ADS)

    Dingemans, L. M.; Papadakis, V. M.; Liu, P.; Adam, A. J. L.; Groves, R. M.

    2015-06-01

    Optical coherence tomography (OCT) is a contactless and non-destructive testing (NDT) technique based on low-coherence interferometry. It has recently become a popular NDT-tool for evaluating cultural heritage. In this study, protective coatings on wood and their penetration into the wood structure were measured with a customized infrared fiber optic OCT instrument. In order to enhance the understanding of the OCT measurements of coatings on real wooden samples, an optimization of the measuring and analyzing methodology was performed by developing an averaging approach and by post-processing the data. The collected information was complemented by data obtained with hyperspectral imaging to allow data from local OCT A-scans to be used in mapping the coating thicknesses over larger areas.

  11. Fluoride antireflection coatings for deep ultraviolet optics deposited by ion-beam sputtering.

    PubMed

    Yoshida, Toshiya; Nishimoto, Keiji; Sekine, Keiichi; Etoh, Kazuyuki

    2006-03-01

    Optically high quality coatings of fluoride materials are required in deep ultraviolet (DUV) lithography. We have applied ion-beam sputtering (IBS) to obtain fluoride films with smooth surfaces. The extinction coefficients were of the order of 10(-4) at the wavelength of 193 nm due to the reduction of their absorption loss. The transmittance of the MgF2/GdF3 antireflection coating was as high as 99.7% at the wavelength of 193 nm. The surfaces of the IBS deposited films were so smooth that the surface roughness of the A1F3/GdF3 film was comparable with that of the CaF2 substrate. The MgF2/GdF3 coating fulfilled the temperature and humidity requirements of military specification. Thus, the IBS deposited fluoride films are promising candidate for use in the DUV lithography optics.

  12. Influence of lithium coating on the optics of Doppler backscatter system

    SciTech Connect

    Zhang, X. H.; Liu, A. D. Zhou, C.; Hu, J. Q.; Wang, M. Y.; Yu, C. X.; Liu, W. D.; Li, H.; Lan, T.; Xie, J. L.

    2015-10-15

    This paper presents the first investigation of the effect of lithium coating on the optics of Doppler backscattering. A liquid lithium limiter has been applied in the Experimental Advanced Superconducting Tokamak (EAST), and a Doppler backscattering has been installed in the EAST. A parabolic mirror and a flat mirror located in the vacuum vessel are polluted by lithium. An identical optical system of the Doppler backscattering is set up in laboratory. The power distributions of the emission beam after the two mirrors with and without lithium coating (cleaned before and after), are measured at three different distances under four incident frequencies. The results demonstrate that the influence of the lithium coating on the power distributions are very slight, and the Doppler backscattering can work normally under the dosage of lithium during the 2014 EAST campaign.

  13. Study on the Sensing Coating of the Optical Fibre CO2 Sensor

    PubMed Central

    Wysokiński, Karol; Napierała, Marek; Stańczyk, Tomasz; Lipiński, Stanisław; Nasiłowski, Tomasz

    2015-01-01

    Optical fibre carbon dioxide (CO2) sensors are reported in this article. The principle of operation of the sensors relies on the absorption of light transmitted through the fibre by a silica gel coating containing active dyes, including methyl red, thymol blue and phenol red. Stability of the sensor has been investigated for the first time for an absorption based CO2 optical fiber sensor. Influence of the silica gel coating thickness on the sensitivity and response time has also been studied. The impact of temperature and humidity on the sensor performance has been examined too. Response times of reported sensors are very short and reach 2–3 s, whereas the sensitivity of the sensor ranges from 3 to 10 for different coating thicknesses. Reported parameters make the sensor suitable for indoor and industrial use. PMID:26694412

  14. Optical anisotropy in self-assembled InAs nanostructures grown on GaAs high index substrate

    PubMed Central

    Bennour, M.; Saidi, F.; Bouzaïene, L.; Sfaxi, L.; Maaref, H.

    2012-01-01

    We present a study of the optical properties of InAs self-assembled nanostructures grown by molecular beam epitaxy on GaAs(11N)A substrates (N = 3–5). Photoluminescence (PL) measurements revealed good optical properties of InAs quantum dots (QDs) grown on GaAs(115)A compared to those grown on GaAs(113)A and (114)A orientations substrate. An additional peak localized at 1.39 eV has been shown on PL spectra of both GaAs(114)A and (113)A samples. This peak persists even at lower power density. Supporting on the polarized photoluminescence characterization, we have attributed this additional peak to the quantum strings (QSTs) emission. A theoretical study based on the resolution of the three dimensional Schrödinger equation, using the finite element method, including strain and piezoelectric-field effect was adopted to distinguish the observed photoluminescence emission peaks. The mechanism of QDs and QSTs formation on such a high index GaAs substrates was explained in terms of piezoelectric driven atoms and the equilibrium surfaces at edges. PMID:22396623

  15. Defect-induced optical absorption and photoluminescence of Verneuil-grown SrTiO 3 crystal

    NASA Astrophysics Data System (ADS)

    Mochizuki, Shosuke; Fujishiro, Fumito; Ishiwata, Ken'ichiro; Shibata, Kohei

    2006-04-01

    In order to clarify the mechanism of the photoluminescence (PL) and other photo-induced effects observed for Verneuil-grown SrTiO 3 crystal, a nominally pure dark-blue as-grown crystal, which has high DC conductivity (σ≃10 Ω cm) and high dielectric constant ( ε>10 at 1 kHz) at room temperature, was prepared and annealed at 973 K in a 90% Ar-10% H 2 mixture gas stream. The optical density (OD) and PL spectra were studied at the different stages of the annealing. In addition to the band gap absorption, at least eight intense optical absorptions due to crystal defects are observed around about 2.9, 2.4, 2.2, 2.1, 1.7, 0.82 and 0.27 eV for the as-grown crystal. With progressing annealing, these absorptions became weak and the crystal became a colorless-transparent insulator. We have found a reasonable connection between the OD spectra and the PL ones.

  16. Optically driven switch turn-off time reduced by opaque coatings

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Turn-off response time of an optically driven switch is reduced by placing an opaque covering over the passivating silicon dioxide members. The coating prevents photon absorption so that carriers are not trapped or stored on the base region, thus shortening turn-off time.

  17. Study of lobster eye optics with iridium coated x-ray mirrors for a rocket experiment

    NASA Astrophysics Data System (ADS)

    Stehlikova, Veronika; Urban, Martin; Nentvich, Ondrej; Inneman, Adolf; Döhring, Thorsten; Probst, Anne-Catherine

    2017-05-01

    In the field of astronomical X-ray telescopes, different types of optics based on grazing incidence mirrors can be used. This contribution describes the special design of a lobster-eye optics in Schmidt's arrangement, which uses dual reflection to increase the collecting area. The individual mirrors of this wide-field telescope are made of at silicon wafers coated with reflecting iridium layers. This iridium coatings have some advantages compared to more common gold layers as is shown in corresponding simulations. The iridium coating process for the X-ray mirrors was developed within a cooperation of the Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague. Different mirror parameters essential for a proper function of the X-ray optics, like the surface microroughness and the problematic of a good adhesion quality of the coatings were studied. After integration of the individual mirrors into the final lobster-eye optics and the corresponding space qualification testing it is planned to fly the telescope in a recently proposed NASA rocket experiment.

  18. Nanometre optical coatings based on strong interference effects in highly absorbing media

    NASA Astrophysics Data System (ADS)

    Kats, Mikhail A.; Blanchard, Romain; Genevet, Patrice; Capasso, Federico

    2013-01-01

    Optical coatings, which consist of one or more films of dielectric or metallic materials, are widely used in applications ranging from mirrors to eyeglasses and photography lenses. Many conventional dielectric coatings rely on Fabry-Perot-type interference, involving multiple optical passes through transparent layers with thicknesses of the order of the wavelength to achieve functionalities such as anti-reflection, high-reflection and dichroism. Highly absorbing dielectrics are typically not used because it is generally accepted that light propagation through such media destroys interference effects. We show that under appropriate conditions interference can instead persist in ultrathin, highly absorbing films of a few to tens of nanometres in thickness, and demonstrate a new type of optical coating comprising such a film on a metallic substrate, which selectively absorbs various frequency ranges of the incident light. These coatings have a low sensitivity to the angle of incidence and require minimal amounts of absorbing material that can be as thin as 5-20 nm for visible light. This technology has the potential for a variety of applications from ultrathin photodetectors and solar cells to optical filters, to labelling, and even the visual arts and jewellery.

  19. Nanometre optical coatings based on strong interference effects in highly absorbing media.

    PubMed

    Kats, Mikhail A; Blanchard, Romain; Genevet, Patrice; Capasso, Federico

    2013-01-01

    Optical coatings, which consist of one or more films of dielectric or metallic materials, are widely used in applications ranging from mirrors to eyeglasses and photography lenses. Many conventional dielectric coatings rely on Fabry-Perot-type interference, involving multiple optical passes through transparent layers with thicknesses of the order of the wavelength to achieve functionalities such as anti-reflection, high-reflection and dichroism. Highly absorbing dielectrics are typically not used because it is generally accepted that light propagation through such media destroys interference effects. We show that under appropriate conditions interference can instead persist in ultrathin, highly absorbing films of a few to tens of nanometres in thickness, and demonstrate a new type of optical coating comprising such a film on a metallic substrate, which selectively absorbs various frequency ranges of the incident light. These coatings have a low sensitivity to the angle of incidence and require minimal amounts of absorbing material that can be as thin as 5-20 nm for visible light. This technology has the potential for a variety of applications from ultrathin photodetectors and solar cells to optical filters, to labelling, and even the visual arts and jewellery.

  20. Optical properties and environmental stability of oxide coatings deposited by reactive sputtering.

    PubMed

    Edlou, S M; Smajkiewicz, A; Al-Jumaily, G A

    1993-10-01

    Refractory metal-oxide coatings are deposited by reactive dc magnetron sputtering in an oxygen environment. The optical constants and the environmental stability of silicon oxide, aluminium oxide, hafnium oxide, zirconium oxide, tantalum oxide, titanium oxide, and a blend of hafnium oxide with silicon oxide are investigated. Properties of both single-layer and multilayer interference filters are examined.

  1. Structural and optical properties of copper-coated substrates for solar thermal absorbers

    NASA Astrophysics Data System (ADS)

    Pratesi, Stefano; De Lucia, Maurizio; Meucci, Marco; Sani, Elisa

    2016-10-01

    Spectral selectivity, i.e. merging a high absorbance at sunlight wavelengths to a low emittance at the wavelengths of thermal spectrum, is a key characteristics for materials to be used for solar thermal receivers. It is known that spectrally selective absorbers can raise the receiver efficiency for all solar thermal technologies. Tubular sunlight receivers for parabolic trough collector (PTC) systems can be improved by the use of spectrally selective coatings. Their absorbance is increased by deposing black films, while the thermal emittance is minimized by the use of properly-prepared substrates. In this work we describe the intermediate step in the fabrication of black-chrome coated solar absorbers, namely the fabrication and characterization of copper coatings on previously nickel-plated stainless steel substrates. We investigate the copper surface features and optical properties, correlating them to the coating thickness and to the deposition process, in the perspective to assess optimal conditions for solar absorber applications.

  2. Optical DLTS for the study of recombination centers in GaAsN grown by chemical beam epitaxy

    NASA Astrophysics Data System (ADS)

    Kowaki, Hiroyuki; Lee, Kan-Hua; Kojima, Takuto; Inagaki, Makoto; Ikeda, Kazuma; Bouzazi, Boussairi; Kojima, Nobuaki; Ohshita, Yoshio; Yamaguchi, Masafumi; Ekins-Daukes, N. J.

    2013-09-01

    New broad DLTS peak signals in GaAsN solar cell, grown by chemical beam epitaxy, were obtained using the combination of optical-irradiation and conventional Deep Level Transient Spectroscopy (DLTS). Those broad peak signals cannot be detected by conventional DLTS method in the dark. The broad peak signals were overlapped with three deep level states at least and showed the increase of DLTS peak intensity. However, the other deep level state (EV+0.60eV) showed no significant change of DLTS peak signals in the dark and optical excitation. The condition of minority carrier injection by optical irradiation indicated that the mechanism of carrier capture and emission at some deep centers had been changed.

  3. Effects of strain cycling on buckling, cracking and spalling of a thermally grown alumina on a nickel-based bond coat

    SciTech Connect

    Wang, J.S.; Evans, A.G.

    1999-01-15

    Strain cycling has been used to study various events that occur in association with an alumina thin layer thermally grown on a Ni-based bond coat. There are three main findings. (i) Buckles propagate with a growth per cycle suggestive of effects of cycling on the friction acting at the separated interfaces. (ii) Cracking of the thermally grown oxide (TGO) occurs within buckles having high ellipticity, subject to a flexural strength typical of fine-grained Al{sub 2}O{sub 3}, with small stressed volume. Such cracking has implications for oxygen ingress and rapid degradation. (iii) Spalling occurs preferentially in those buckles that previously crack. The measurements are analyzed using the mechanics of buckle propagation, bending and kinking.

  4. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  5. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  6. In-situ grown MgO-ZnO ceramic coating with high thermal emittance on Mg alloy by plasma electrolytic oxidation

    NASA Astrophysics Data System (ADS)

    Li, Hang; Lu, Songtao; Qin, Wei; Wu, Xiaohong

    2017-07-01

    Intense solar radiation and internal heat generation determine the equilibrium temperature of an in-orbit spacecraft. Thermal control coatings with low solar absorptance and high thermal emittance effectively maintain the thermal equilibrium within safe operating limits for exposed, miniaturized and highly integrated components. A novel ceramic coating with high thermal emittance and good adhesion was directly prepared on the Mg substrate using an economical process of controlled plasma electrolytic oxidation (PEO) in the electrolyte containing ZnSO4. XRD and XPS results showed that this coating was mainly composed of the MgO phase as well as an unusual ZnO crystalline phase. The adhesive strength between the coating and substrate determined by a pull-off test revealed an excellent adhesion. Thermal and optical properties test revealed that the coating exhibited a high infrared emittance of 0.88 (2-16 μm) and low solar absorptance of 0.35 (200-2500 nm). The result indicated that the formation of ZnO during the PEO process played an important role in the improvement of the coating emittance. The process developed provides a simple surface method for improving the thermal emittance of Mg alloy, which presents a promising application prospect in the thermal management of the spacecraft.

  7. Double-layer optical fiber coating analysis in MHD flow of an elastico-viscous fluid using wet-on-wet coating process

    NASA Astrophysics Data System (ADS)

    Khan, Zeeshan; Islam, Saeed; Shah, Rehan Ali; Khan, Muhammad Altaf; Bonyah, Ebenezer; Jan, Bilal; Khan, Aurangzeb

    Modern optical fibers require a double-layer coating on the glass fiber in order to provide protection from signal attenuation and mechanical damage. The most important plastic resins used in wires and optical fibers are plastic polyvinyl chloride (PVC) and low and high density polyethylene (LDPE/HDPE), nylon and Polysulfone. One of the most important things which affect the final product after processing is the design of the coating die. In the present study, double-layer optical fiber coating is performed using melt polymer satisfying Oldroyd 8-constant fluid model in a pressure type die with the effect of magneto-hydrodynamic (MHD). Wet-on-wet coating process is applied for double-layer optical fiber coating. The coating process in the coating die is modeled as a simple two-layer Couette flow of two immiscible fluids in an annulus with an assigned pressure gradient. Based on the assumptions of fully developed laminar and MHD flow, the Oldroyd 8-constant model of non-Newtonian fluid of two immiscible resin layers is modeled. The governing nonlinear equations are solved analytically by the new technique of Optimal Homotopy Asymptotic Method (OHAM). The convergence of the series solution is established. The results are also verified by the Adomian Decomposition Method (ADM). The effect of important parameters such as magnetic parameter Mi , the dilatant constant α , the Pseodoplastic constant β , the radii ratio δ , the pressure gradient Ω , the speed of fiber optics V , and the viscosity ratio κ on the velocity profiles, thickness of coated fiber optics, volume flow rate, and shear stress on the fiber optics are investigated. At the end the result of the present work is also compared with the experimental results already available in the literature by taking non-Newtonian parameters tends to zero.

  8. Multienergy gold ion implantation for enhancing the field electron emission characteristics of heterogranular structured diamond films grown on Au-coated Si substrates

    NASA Astrophysics Data System (ADS)

    Sankaran, K. J.; Manoharan, D.; Sundaravel, B.; Lin, I. N.

    2016-09-01

    Multienergy Au-ion implantation enhanced the electrical conductivity of heterogranular structured diamond films grown on Au-coated Si substrates to a high level of 5076.0 (Ω cm)-1 and improved the field electron emission (FEE) characteristics of the films to low turn-on field of 1.6 V/μm, high current density of 5.4 mA/cm2 (@ 2.65 V/μm), and high lifetime stability of 1825 min. The catalytic induction of nanographitic phases in the films due to Au-ion implantation and the formation of diamond-to-Si eutectic interface layer due to Au-coating on Si together encouraged the efficient conducting channels for electron transport, thereby improved the FEE characteristics of the films.

  9. Au nanocrystals grown on a better-defined one-dimensional tobacco mosaic virus coated protein template genetically modified by a hexahistidine tag

    NASA Astrophysics Data System (ADS)

    Liu, Nan; Wang, Chong; Zhang, Wei; Luo, Zhaopeng; Tian, Dandan; Zhai, Niu; Zhang, Hongfei; Li, Zhonghao; Jiang, Xingyi; Tang, Gangling; Hu, Qingyuan

    2012-08-01

    In this paper, tobacco mosaic virus (TMV) coated protein (CP) was genetically modified by introducing a hexahistidine tag into it for a well-defined one-dimensional template, on which Au nanocrystals (NCs) were grown. The results showed that genetic modification could not only ameliorate the one-dimensional structure of the template, but also improve the growth density of Au NCs on the template. This indicated that genetic modification could be an effective method to modulate the structure of the TMVCP template-based nanocomposites allowing for a broader application of them.

  10. Electrical and Optical Studies of Defect Structure of HgCdTe Films Grown by Molecular Beam Epitaxy

    NASA Astrophysics Data System (ADS)

    Świątek, Z.; Ozga, P.; Izhnin, I. I.; Fitsych, E. I.; Voitsekhovskii, A. V.; Korotaev, A. G.; Mynbaev, K. D.; Varavin, V. S.; Dvoretsky, S. A.; Mikhailov, N. N.; Yakushev, M. V.; Bonchyk, A. Yu.; Savytsky, H. V.

    2016-07-01

    Electrical and optical studies of defect structure of HgCdTe films grown by molecular beam epitaxy (MBE) are performed. It is shown that the peculiarity of these films is the presence of neutral defects formed at the growth stage and inherent to the material grown by MBE. It is assumed that these neutral defects are the Te nanocomplexes. Under ion milling, they are activated by mercury interstitials and form the donor centers with the concentration of 1017 cm-3, which makes it possible to detect such defects by measurements of electrical parameters of the material. Under doping of HgCdTe with arsenic using high temperature cracking, the As2 dimers are present in the arsenic flow and block the neutral Te nanocomplexes to form donor As2Te3 complexes. The results of electrical studies are compared with the results of studies carried out by micro-Raman spectroscopy.

  11. Effect of surface coating and organic matter on the uptake of CeO2 NPs by corn plants grown in soil: Insight into the uptake mechanism

    PubMed Central

    Zhao, Lijuan; Peralta-Videa, Jose R.; Varela-Ramirez, Armando; Castillo-Michel, Hiram; Li, Chunqiang; Zhang, Jianying; Aguilera, Renato J.; Keller, Arturo A.; Gardea-Torresdey, Jorge L.

    2015-01-01

    Little is known about the fate, transport, and bioavailability of CeO2 nanoparticles (NPs) in soil. Moreover, there are no reports on the effect of surface coating upon NPs uptake by plants. In this study, Zea mays plants were grown for one month in unenriched and organic soils treated with coated and uncoated CeO2 NPs. In addition, plants were exposed to fluorescein isothiocyanate (FITC)-stained CeO2 NPs and analyzed in a confocal microscope. In organic soil, roots from uncoated and coated NPs at 100, 200, 400, and 800 mg kg−1 had 40, 80, 130, and 260% and 10, 70, 90, and 40% more Ce, respectively, compared to roots from unenriched soil. Conversely, shoots of plants from unenriched soil had significantly more Ce compared with shoots from organic soil. Confocal fluorescence images showed FITC-stained CeO2 NP aggregates in cell walls of epidermis and cortex, suggesting apoplastic pathway. The μXRF results revealed the presence of CeO2 NP aggregates within vascular tissues. To the authors knowledge this is the first report on the effects of surface coating and organic matter on Ce uptake from CeO2 NPs and upon the mechanisms of CeO2 NPs uptake by higher plants PMID:22633924

  12. Characterization of ZnO thin films grown on different p-Si substrate elaborated by solgel spin-coating method

    SciTech Connect

    Chebil, W.; Fouzri, A.; Fargi, A.; Azeza, B.; Zaaboub, Z.; and others

    2015-10-15

    Highlights: • High quality ZnO thin films grown on different p-Si substrates were successful obtained by sol–gel process. • PL measurement revealed that ZnO thin film grown on porous Si has the better optical quality. • I–V characteristics for all heterojunctions exhibit successful diode formation. • The diode ZnO/PSi shows a better photovoltaic effect under illumination with a maximum {sub Voc} of 0.2 V. - Abstract: In this study, ZnO thin films are deposited by sol–gel technique on p-type crystalline silicon (Si) with [100] orientation, etched silicon and porous silicon. The structural analyses showed that the obtained thin films were polycrystalline with a hexagonal wurtzite structure and preferentially oriented along the c-axis direction. Morphological study revealed the presence of rounded and facetted grains irregularly distributed on the surface of all samples. PL spectra at room temperature revealed that ZnO thin film grown on porous Si has a strong UV emission with low defects in the visible region comparing with ZnO grown on plat Si and etched Si surface. The heterojunction parameters were evaluated from the (I–V) under dark and illumination at room temperature. The ideality factor, barrier height and series resistance of heterojunction grown on different p-Si substrates are determined by using different methods. Best electrical properties are obtained for ZnO layer deposited on porous silicon.

  13. Anomalous thickness-dependent optical energy gap of ALD-grown ultra-thin CuO films

    NASA Astrophysics Data System (ADS)

    Tripathi, T. S.; Terasaki, I.; Karppinen, M.

    2016-11-01

    Usually an inverse square relation between the optical energy gap and the size of crystallites is observed for semiconducting materials due to the strong quantum localization effect. Coulomb attraction that may lead to a proportional dependence is often ignored or considered less important to the optical energy gap when the crystallite size or the thickness of a thin film changes. Here we report a proportional dependence between the optical energy gap and the thickness of ALD-grown CuO thin films due to a strong Coulomb attraction. The ultrathin films deposited in the thickness range of 9-81 nm show a p-type semiconducting behavior when analyzed by Seebeck coefficient and electrical resistivity measurements. The indirect optical energy gap nature of the films is verified from UV-vis spectrophotometric measurements. A progressive increase in the indirect optical energy gap from 1.06 to 1.24 eV is observed with the increase in the thickness of the films. The data are analyzed in the presence of Coulomb attractions using the Brus model. The optical energy gap when plotted against the cubic root of the thickness of the films shows a linear dependence.

  14. Optical parameters of Al-doped ZnO nanorod array thin films grown via the hydrothermal method.

    PubMed

    Kim, Soaram; Kim, Min Su; Nam, Giwoong; Park, Hyunggil; Yoon, Hyunsik; Leem, Jae-Young

    2013-09-01

    ZnO seed layers were deposited onto a quartz substrate using the sol--gel method, and Al-doped ZnO (AZO) nanorod array thin films with different Al concentrations that ranged from 0 to 2.0 at. % were grown on the ZnO seed layers via the hydrothermal method. Optical parameters, including the optical band gap, the absorption coefficient, the Urbach energy, the refractive index, the dispersion parameter, and the optical conductivity, were studied to investigate the effects of Al doping on the optical properties of AZO nanorod array thin films. The optical band gaps of the ZnO and AZO nanorod array thin films were 3.206 at 0 at.%, 3.214 at 0.5 at.%, 3.226 at 1.5 at.%, and 3.268 at 2.0 at.%. The Urbach energy gradually decreased from 126 meV (0 at.%) to 70 meV (2.0 at.%) as the Al concentration was increased. The dispersion energy, the single-oscillator energy, the average oscillator wavelength, the average oscillator strength, the refractive index, and the optical conductivity of the AZO nanorod array thin films were all affected by Al doping.

  15. Structural, magnetic and optical properties of a dilute magnetic semiconductor based on Ce{sub 1−x}Co{sub x}O{sub 2} thin film grown on LaAlO{sub 3}

    SciTech Connect

    Mahmoud, Waleed E.; Al-Ghamdi, A.A.; Al-Agel, F.A.; Al-Arfaj, E.; Shokr, F.S.; Al-Gahtany, S.A.; Alshahrie, Ahmed; Jalled, Ouissem; Bronstein, L.M.; Beall, Gary W.

    2015-12-15

    Highlights: • Co doped CeO{sub 2} was grown on LaAlO{sub 3} (0 0 1) via a modified sol–gel spin-coating technique. • The concentration of the Co ions was varied from 1 to 15 at.%. • The incorporation of 5 at.% of Mn ions was found to provide formation of exceptionally magnetic moment. • This amount demonstrated a giant magnetic moment of 1.09 μ{sub B}/Co. • This amount reduced the optical band gap and enhanced the optical performance. - Abstract: The enhancement of the room temperature ferromagnetism and optical properties of the dilute magnetic metal oxides is a crucial clue to construct spin-based optoelectronic devices. In this work, Ce{sub 1−x}Co{sub x}O{sub 2} (0.01 ≤ x ≤0.15) thin films were prepared via ethylene glycol modified sol–gel spin coating technique on the LaAlO{sub 3} (0 0 1) substrate to enhance their room temperature ferromagnetism and optical properties. The structures, magnetic and optical properties of the prepared films were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, SQUID magnetometer, X-ray photoelectron spectroscopy and UV–vis spectrophotometer. The results demonstrated that a single phase cubic structure was formed, implying the substitution of Co ions into the Ce ions sites. The prepared films showed room temperature ferromagnetism with saturation magnetic moment of 1.09 μ{sub B}/Co was achieved for 5 at.% Co-doped CeO{sub 2}. This film exhibited high optical transparency of 85% and low optical band energy gap of 3.39 eV. The improved magnetic and optical properties are argued to the increase of the density of the oxygen vacancies into the cerium oxide crystal structure due to the incorporation of Co ions.

  16. Characterization of the optical properties of hydrophobic coatings and realization of high performance AR coatings with dust- and water-repellent properties

    NASA Astrophysics Data System (ADS)

    Bruynooghe, S.; Spinzig, S.; Fliedner, M.; Hsu, G. J.

    2008-09-01

    Hydrophobic coatings enable the manufacture of easy-to-clean surfaces having dust- and water-repellent properties. In this work, a hydrophobic coating is deposited as a top layer on an antireflective (AR) multilayer system comprising a MgF2 upper layer to produce low reflectance optical surfaces at a normal incident angle in the visible spectrum with dust- and water-repellent properties for applications in precision optics. We report on the preparation and characterization of the optical properties of hydrophobic coatings deposited using a vacuum evaporation process and a commercially available water repellent substance. By means of a grazing incidence X-ray reflectometer it is shown that the hydrophobic coating can be considered, from an optical point of view, as two adjacent thin layers having specific thicknesses and densities. In fact, the hydrophobic layer is one monolayer comprising molecular chains with anchoring groups responsible for the chemical bond with the substrate material and functional groups responsible for the water- and oil-repellent properties. Optical constants are determined using a spectroscopic ellipsometer and are taken into account in the final multilayer system design. High performance AR coatings having an average reflectance of 0.14% at 7° incident angle in the 400-680nm spectral range together with a pleasing purple-red reflex color are produced. Coated lenses exhibit an excellent abrasion resistance, environmental stability, resistance to cleaning agents, homogeneity and water repellence with contact angles against water higher than 110°.

  17. Dynamic response of tapered optical multimode fiber coated with carbon nanotubes for ethanol sensing application.

    PubMed

    Shabaneh, Arafat; Girei, Saad; Arasu, Punitha; Mahdi, Mohd; Rashid, Suraya; Paiman, Suriati; Yaacob, Mohd

    2015-05-04

    Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%), the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s) towards ethanol.

  18. Optical Fiber Relative Humidity Sensor Based on a FBG with a Di-Ureasil Coating

    PubMed Central

    Correia, Sandra F. H.; Antunes, Paulo; Pecoraro, Edison; Lima, Patrícia P.; Varum, Humberto; Carlos, Luis D.; Ferreira, Rute A. S.; André, Paulo S.

    2012-01-01

    In this work we proposed a relative humidity (RH) sensor based on a Bragg grating written in an optical fiber, associated with a coating of organo-silica hybrid material prepared by the sol-gel method. The organo-silica-based coating has a strong adhesion to the optical fiber and its expansion is reversibly affected by the change in the RH values (15.0–95.0%) of the surrounding environment, allowing an increased sensitivity (22.2 pm/%RH) and durability due to the presence of a siliceous-based inorganic component. The developed sensor was tested in a real structure health monitoring essay, in which the RH inside two concrete blocks with different porosity values was measured over 1 year. The results demonstrated the potential of the proposed optical sensor in the monitoring of civil engineering structures. PMID:23012521

  19. Dynamic Response of Tapered Optical Multimode Fiber Coated with Carbon Nanotubes for Ethanol Sensing Application

    PubMed Central

    Shabaneh, Arafat; Girei, Saad; Arasu, Punitha; Mahdi, Mohd; Rashid, Suraya; Paiman, Suriati; Yaacob, Mohd

    2015-01-01

    Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%), the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s) towards ethanol. PMID:25946634

  20. Structural and optical properties of cobalt slanted nanopillars conformally coated with few-layer graphene

    SciTech Connect

    Wilson, Peter M.; Lipatov, Alexey; Schmidt, Daniel; Schubert, Eva; Schubert, Mathias; Hofmann, Tino E-mail: thofmann@engr.unl.edu; Sinitskii, Alexander E-mail: thofmann@engr.unl.edu

    2015-06-08

    Optical characterization of anisotropic multicomponent nanostructures is generally not a trivial task, since the relation between a material's structural properties and its permittivity tensor is nonlinear. In this regard, an array of slanted cobalt nanopillars that are conformally coated with few-layer graphene is a particularly challenging object for optical characterization, as it has a complex anisotropic geometry and comprises several materials with different topologies and filling fractions. Normally, a detailed characterization of such complex nanostructures would require a combination of several microscopic and spectroscopic techniques. In this letter, we demonstrate that the important structural parameters of these graphene-coated sculptured thin films can be determined using a fast and simple generalized spectroscopic ellipsometry test combined with an anisotropic Bruggeman effective medium approximation. The graphene coverage as well as structural parameters of nanostructured thin films agree excellently with electron microscopy and Raman spectroscopy observations. The demonstrated optical approach may also be applied to the characterization of other nanostructured materials.

  1. Optical, electrical and surface characterization of mercuric iodide platelets grown in the HgI{sub 2}-HI-H{sub 2}O system

    SciTech Connect

    Fornaro, L.; Chen, H.; Chattopadhyay, K.; Chen, K.T.; Burger, A.

    1998-12-31

    The optical, electrical and surface properties of mercuric iodide platelets grown from solution in a HgI{sub 2}-HI-H{sub 2}O system were investigated by comparing them with Physical Vapor Transport (PVT) grown crystals. The absence of bulk imperfections and the uniformity of the as-grown surfaces and the KI solution etched surfaces were confirmed by optical microscopy. The as-grown surface uniformity is higher for solution grown crystals than that of PVT crystals, since the platelets do not have to be cleaved or polished. AFM studies show that the roughness for the cleaved, aged and etched surfaces were 0.06 nm, 0.48 nm and 0.3 nm respectively. Low temperature photoluminescence properties were measured for the two kinds of crystals and will be discussed. However, I-V curves give higher current density and lower apparent resistivity values for the solution grown than for PVT grown crystals. Correlations between optical and surface quality as well as the electrical properties of the crystals grown from both solution and PVT methods are also discussed.

  2. YBCO Coated Conductor with an Integrated Optical Fiber Sensor

    SciTech Connect

    Sathyamurthy, Srivatsan; Rupich, Marty; Schwartz, Justin

    2016-03-31

    The primary objectives of the Phase I Project was to develop a proof-of-principle for a concept of integrating an optical fiber sensor into the laminated 2G wire, there by producing a functionalized 2G wire with self-monitoring capabilities

  3. Selection of Optical Cavity Surface Coatings for 1micron Laser Based Missions

    NASA Technical Reports Server (NTRS)

    Hedgeland, Randy J.; Straka, Sharon; Matsumura, Mark; Hammerbacher, Joseph

    2004-01-01

    The particulate surface cleanliness level on several coatings for aluminum and beryllium substrates were examined for use in the optical cavities of high pulse energy Nd:YAG Q-switched, diode-pumped lasers for space flight applications. Because of the high intensity of the lasers, any contaminants in the laser beam path could damage optical coatings and limit the instrument mission objectives at the operating wavelength of 1 micron (micrometer). Our goal was to achieve an EST-STD-CC1246D Level 100 particulate distribution or better to ensure particulate redistribution during launch would not adversely affect the performance objectives. Tapelifts were performed to quantify the amount of particles using in-house developed procedures. The primary candidate coatings included chromate conversion coating aluminum (Al), uncoated Al electroless Nickel (Ni) on Al, Ni-gold (Au) on Al, anodized Al, and gold (Au)/Ni on Beryllium (Be). The results indicate that there were advantages in Ni and Au coating applications for the two major substrates, Al and Be, when considering applications that need to meet launch environments.

  4. Optical Properties of Thermal Control Coatings After Weathering, Simulated Ascent Heating, and Simulated Space Radiation Exposure

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Tuan, George C.; Westheimer, David T.; Peters, Wanda C.; Kauder, Lonny R.

    2008-01-01

    Spacecraft radiators reject heat to their surroundings and coatings play an important role in this heat rejection. The coatings provide the combined optical properties of low solar absorptance and high infrared emittance. The coatings are applied to the radiator panel in a number of ways, including conventional spraying, plasma spraying, or as an applique. Not designed for a terrestrial weathering environment, the durability of spacecraft paints, coatings, and appliques upon exposure to weathering and subsequent exposure to ascent heating, solar wind, and ultraviolet radiation was studied. In addition to traditional aluminum panels, new isocyanate ester composite panels were exposed for a total of 90 days at the Atmospheric Exposure Site of Kennedy Space Center's (KSC) Beach Corrosion Facility for the purpose of identifying their durability to weathering. Selected panel coupons were subsequently exposed to simulated ascent heating, solar wind, and vacuum ultraviolet (UV) radiation to identify the effect of a simulated space environment on as-weathered surfaces. Optical properties and adhesion testing were used to document the durability of the paints, coatings, and appliques.

  5. Silicone rubber-coated highly sensitive optical fiber sensor for temperature measurement

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Vanita; Gangwar, Rahul Kumar; Singh, Vinod Kumar

    2016-12-01

    A silicone rubber-coated Mach-Zehnder interferometer (MZI) is proposed and applied to temperature measurement. The MZI is fabricated by splicing single mode fiber between a short section of no-core fiber (NCF) and the ultra-abrupt taper region. The sensing length of MZI is coated with liquid silicone rubber to enhance the temperature sensitivity. Here, NCF is used to excite the higher order cladding mode, the ultra-abrupt taper region acts as a optical fiber coupler, and the silicone rubber coating on sensing length is used as solid cladding material instead of liquid. The enhancement of the sensitivity of a device is due to the high refractive index (1.42) and thermo-optic coefficient (-1.4×10-4/°C) of silicone rubber as compared to liquid cladding temperature sensors. The experiment was performed for both coated and uncoated MZI and the results were compared. The MZI exhibits a high temperature sensitivity of 253.75 and 121.26 pm/°C for coated and uncoated sensing probes, respectively, in the temperature range from 30°C to 75°C.

  6. Method for reducing the effect of environmental contamination of Sol-gel optical coatings

    SciTech Connect

    Burnham, A. K.; Ertel, J. R.; Frieders, S. C.; Thomas, I. M.

    1998-07-28

    AR coatings prepared from colloidal suspensions of silica have a large surface area because of their porosity. The surface is quite polar and readily absorbs vapor contamination to the detriment of the optical performance and the laser damage threshold. This effect is particularly bad in ''dirty'' vacuum systems such as target chambers. The polar surface is due to residual Si-OH and Si-ethoxyl groups formed as a result of the method of preparation of the coating suspension. We have now found that these groups can be removed by further treatment of the coating after preparation. This involves two steps, the first being exposure to ammonia and water vapor which hydrolyzes the ethoxyl groups to hydroxyl groups with the formation of more Si-OH groups. Some of these react further by self condensation to Si-0-Si linkages. The remaining Si-OH groups are removed in the second step by reaction with hexamethyl-disilazane (HMDS) which converts them to trimethylsilyl groups. The latter are completely non-polar and substantially eliminate vapor absorption. We have carried out a series of tests involving exposure of treated and untreated coatings to various types of vapor contamination and followed the degree of contamination by the reduction in optical transmission. In all cases the treated coatings showed a significant reduction in transmission loss. These tests also provide guidance as to which materials are acceptable for use.

  7. Silver nanowire/optical adhesive coatings as transparent electrodes for flexible electronics.

    PubMed

    Miller, Michael S; O'Kane, Jessica C; Niec, Adrian; Carmichael, R Stephen; Carmichael, Tricia Breen

    2013-10-23

    We present new flexible, transparent, and conductive coatings composed of an annealed silver nanowire network embedded in a polyurethane optical adhesive. These coatings can be applied to rigid glass substrates as well as to flexible polyethylene terephthalate (PET) plastic and elastomeric polydimethylsiloxane (PDMS) substrates to produce highly flexible transparent conductive electrodes. The coatings are as conductive and transparent as indium tin oxide (ITO) films on glass, but they remain conductive at high bending strains and are more durable to marring and scratching than ITO. Coatings on PDMS withstand up to 76% tensile strain and 250 bending cycles of 15% strain with a negligible increase in electrical resistance. Since the silver nanowire network is embedded at the surface of the optical adhesive, these coatings also provide a smooth surface (root mean squared surface roughness<10 nm), making them suitable as transparent conducting electrodes in flexible light-emitting electrochemical cells. These devices continue to emit light even while being bent to radii as low as 1.5 mm and perform as well as unstrained devices after 20 bending cycles of 25% tensile strain.

  8. High Performance Optical Coatings Utilizing Tailored Refractive Index Nanoporous Thin Films

    NASA Astrophysics Data System (ADS)

    Poxson, David J.

    Refractive index is perhaps the most important quantity in optics. It is particularly relevant in the field of optical coatings, where the refractive index appears in virtually every optics equation as a figure of merit. Recently it has been demonstrated through control of the deposition angle during oblique-angle electron-beam deposition, nanoporous films of virtually any desired porosity may be accurately deposited. As the porosity of a nanoporous film directly relates to its effective refractive index, the refractive index value of a film may be tailored to any value between that of the bulk material and close to that of air. These two characteristics, namely; (i) tailored-refractive index and (ii) very low-refractive index values close to that of air, offer significant advantages in the design and optical performance in all optical coating applications. In this dissertation we explore optical coating applications whose performance can be greatly enhanced by utilization of a tailored- and low-refractive index nanoporous material system. One such important application is in the design and fabrication of broadband, omnidirectional antireflection (AR) coatings on solar cell devices. To harness the full spectrum of solar energy, Fresnel reflections at the surface of a photovoltaic cell must be reduced as much as possible over the relevant solar wavelength range and over a wide range of incident angles. However, the development of AR coatings embodying omni-directionality over a wide range of wavelengths is challenging. By utilizing the tailored- and low-refractive index properties of the nanoporous material system, in conjunction with a computational genetic algorithm and a predictive quantitative model for the porosity of such nanoporous films, truly optimized AR coatings can be designed and fabricated on solar cells. Here we show that these optimized AR structures demonstrate significant improvement to overall device efficiency. Traditionally, nanoporous films

  9. Development of damage resistant sputtered oxide optical coatings for use at 248 NM

    SciTech Connect

    Pawlewicz, W.T.; Martin, P.M.; Hays, D.D.; Mann, I.B.

    1981-10-01

    This report summarizes the results of a six-month effort to develop damage-resistant Kr*F laser mirrors by using and refining reactive sputter deposition techniques for the fabricaton of multilayer oxide optical coatings. Mirror performance goals included a reflectivity of 99% at 248 nm and a laser damage threshold of 5 J/cm/sup 2/ for 20 ns pulses. Oxide multilayer coating combinations selected for development were SiO/sub 2//Al/sub 2/O/sub 3/, SiO/sub 2//HfO/sub 2/ and SiO/sub 2//Y/sub 2/O/sub 3/. Selection was based on review and compilation of the optical properties of oxide materials reported in the recent literature. Twenty-eight coatings of selected designs were fabricated on LLNL substrates for laser damage testing by LLNL. Forty other coatings were fabricated on PNL substrates for optical, microstructural and topographical characterization by PNL aimed at optimization of their performance. Specimens for damage testing consisted of single layers of Al/sub 2/O/sub 3/, HfO/sub 2/ and Y/sub 2/O/sub 3/ in thicknesses of lambda/2, 3lambda/2 and 2lambda at 248 nm plus high reflectors of the design LL (HL)/sup m/ HLL.

  10. Damage to coated ZnSe optical components by high-power CO2 laser radiation

    NASA Astrophysics Data System (ADS)

    Haas, C. R.; Kreutz, Ernst-Wolfgang; Wesner, David A.

    1994-07-01

    Coated ZnSe optical components are irradiated with high-power, pulsed CO2 laser radiation ((lambda equals 10.6 micrometers , pulse length approximately 100 ns) at fluences up to 210 J/cm2. The components are characterized at various stages of irradiation by thermography, optical microscopy, stylus profilometry, and surface chemical analysis (x-ray photoemission and Auger electron spectroscopy). During irradiation no temperature in the component surface is observed. Two types of coating damage occur within the irradiated area of the component: a breaking apart of the ZnSe overlayer of the coating system over relatively large areas, and the formation of isolate craters of diameter approximately 30 - 50 micrometers extending in depth approximately 3 micrometers through the coating system down to the ZnSe substrate. Chemically, the irradiated area is characterized by an oxidation of both Zn and Se and an increase in the stoichiometric ratio of Zn to Se. These effects are especially pronounced at the crater defects, and are attributed to localized optical absorption, leading to thermal stress and chemical reactions of Zn and Se with atmospheric or adsorbed water and/or oxygen.

  11. Anti-reflection coated optical fibers for use in thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

    2017-02-01

    The Thulium fiber laser (TFL) is being studied as an alternative to Holmium:YAG laser for lithotripsy. The near single mode TFL beam profile enables transmission of higher laser power through smaller optical fibers than possible during Holmium laser lithotripsy. Current free-space coupling of collimated TFL output beam into a disposable silica fiber for ureteroscopy is limited by back-reflected light from the fiber input surface, which may result in laser shutoff or damage, if left unchecked. This study examines whether anti-reflection (AR) coated fibers may sufficiently reduce back-reflected light to prevent laser shutoff, increase fiber optic transmission, and potentially increase laser stone ablation rates as well. Fiber optic transmission and stone ablation studies were conducted comparing uncoated and AR-coated 105- and 200-μm-core fibers. Magnified images of proximal fiber surfaces were taken before and after each trial to examine for AR-coating damage. TFL wavelength of 1908 nm was coupled into silica fibers, with incrementally increasing pulse energy (5-35 mJ), fixed 500-μs pulse duration, and pulse rates of 50-300 Hz. For each pulse rate, 100,000 pulses were also delivered through the fibers to examine for potential damage. Back-reflection at proximal fiber surface was reduced from 3.25% with uncoated fibers to 0.06% with AR coated fibers. For both fiber diameters, output power was stable, and no proximal fiber damage was observed after delivery of 100,000 pulses at 35 mJ, 300 Hz, and 10.5 W average power. There was no significant difference in stone ablation rates between fiber diameters (105 vs. 200 μm) or bare or AR-coated fibers. Laser shutdown was not observed using AR-coated fibers, which reduce back-reflection and improve energy transmission, but do not improve stone ablation rates.

  12. Broad range tuning of structural and optical properties of Zn x Mg1-x O nanostructures grown by vapor transport method

    NASA Astrophysics Data System (ADS)

    Vanjaria, Jignesh V.; Azhar, Ebraheem Ali; Yu, Hongbin

    2016-11-01

    One-dimensional (1D) Zn x Mg1-x O nanomaterials have drawn global attention due to their remarkable chemical and physical properties, and their diverse current and future technological applications. In this work, 1D ZnMgO nanostructures with different magnesium concentrations and different morphologies were grown directly on zinc oxide-coated silicon substrates by thermal evaporation of zinc oxide, magnesium boride and graphite powders. Highly well-defined Mg-rich ZnMgO nanorods with a rock salt structure and Zn-rich ZnMgO nanostructures with a wurtzite structure have been deposited individually by careful optimization of the source mixture and process parameters. Structural and optical properties of the deposited products were studied by scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, and Raman spectroscopy. Cathodoluminescence measurements demonstrate strong dominant peaks at 3.3 eV in Mg poor ZnMgO nanostructures and 4.8 eV in Mg rich nanostructures implying that the ZnMgO nanostructures can be used for the fabrication of deep UV optoelectronic devices. A mechanism for the formation and achieved diverse morphology of the ZnMgO nanostructures was proposed based on the characterization results.

  13. Optical characteristics of ZnO single crystal grown by the hydrothermal method

    SciTech Connect

    Chen, G. Z.; Yin, J. G. E-mail: yjg@siom.ac.cn; Zhang, L. H.; Zhang, P. X.; Wang, X. Y.; Liu, Y. C.; Zhang, C. L.; Gu, S. L.; Hang, Y.

    2015-12-15

    ZnO single crystals have been grown by the hydrothermal method. Raman scattering and Photoluminescence spectroscopy (PL) have been used to study samples of ZnO that were unannealed or annealed in different ambient gases. It is suggested that the green emission may originate from defects related to copper in our samples.

  14. Raman sensing of fuel gases using a reflective coating capillary optical fiber

    NASA Astrophysics Data System (ADS)

    Buric, M. P.; Chen, K.; Falk, J.; Velez, R.; Woodruff, S.

    2009-05-01

    Hollow core fiber optics enable gas phase Raman spectroscopy with relatively low power laser excitation sources. A Raman sensor for gaseous fuel analysis is demonstrated using silver coated capillary optical fiber as the sample cell and as the signal collection optic. Using laser powers with as little as a few milliwatts excitation power, the majority species of natural gas and syngas are readily detected, as well as oxygen and nitrogen in a single sensor system. Exchange rates in the capillary optical fiber are high enough to enable optical analysis in sub-second response time for real time sensing and control. Because this one sensor system simultaneously detects and resolves all the component species, real time feedback to the combustion control system of fuel content and properties is enabled.

  15. Design of a superluminal ring laser gyroscope using multilayer optical coatings with huge group delay

    NASA Astrophysics Data System (ADS)

    Qu, Tianliang; Yang, Kaiyong; Han, Xiang; Wu, Suyong; Huang, Yun; Luo, Hui

    2014-11-01

    We propose and analyze a superluminal ring laser gyroscope (RLG) using multilayer optical coatings with huge group delay (GD). This GD assisted superluminal RLG can measure the absolute rotation with a giant sensitivity-enhancement factor of ~103; while, the broadband FWHM of the enhancement factor can reach 20 MHz. This superluminal RLG is based on a traditional RLG with minimal re-engineering, and beneficial for miniaturization according to theoretical calculation. The idea of using GD coatings as a fast-light medium will shed lights on the design and application of fast-light sensors.

  16. Design of a superluminal ring laser gyroscope using multilayer optical coatings with huge group delay

    PubMed Central

    Qu, Tianliang; Yang, Kaiyong; Han, Xiang; Wu, Suyong; Huang, Yun; Luo, Hui

    2014-01-01

    We propose and analyze a superluminal ring laser gyroscope (RLG) using multilayer optical coatings with huge group delay (GD). This GD assisted superluminal RLG can measure the absolute rotation with a giant sensitivity-enhancement factor of ~103; while, the broadband FWHM of the enhancement factor can reach 20 MHz. This superluminal RLG is based on a traditional RLG with minimal re-engineering, and beneficial for miniaturization according to theoretical calculation. The idea of using GD coatings as a fast-light medium will shed lights on the design and application of fast-light sensors. PMID:25403698

  17. Wideband optical coatings for artwork protection from ultraviolet and infrared radiation damage

    NASA Astrophysics Data System (ADS)

    Piegari, Angela M.; Polato, Pietro

    2003-11-01

    The damaging effects of illumination on artworks are well known. Art conservation requires protection against vandalism and protection against radiation damage. Glass is an appropriate material for both requirements, but it partially transmits ultraviolet and infrared radiation. An optical coating on glass that eliminates the ultraviolet and the infrared radiation coming from natural or artificial source of illumination, is proposed. This coated glass, positioned in front of the artwork, is also able to reduce the visible radiation without altering the vision or the color rendering.

  18. Design of a superluminal ring laser gyroscope using multilayer optical coatings with huge group delay.

    PubMed

    Qu, Tianliang; Yang, Kaiyong; Han, Xiang; Wu, Suyong; Huang, Yun; Luo, Hui

    2014-11-18

    We propose and analyze a superluminal ring laser gyroscope (RLG) using multilayer optical coatings with huge group delay (GD). This GD assisted superluminal RLG can measure the absolute rotation with a giant sensitivity-enhancement factor of ~10(3); while, the broadband FWHM of the enhancement factor can reach 20 MHz. This superluminal RLG is based on a traditional RLG with minimal re-engineering, and beneficial for miniaturization according to theoretical calculation. The idea of using GD coatings as a fast-light medium will shed lights on the design and application of fast-light sensors.

  19. Thermal and optical analysis of selective absorber coatings based on soot for applications in solar cookers

    NASA Astrophysics Data System (ADS)

    Servín, H.; Peña, M.; Sobral, H.; González, M.

    2017-01-01

    The thermal and optical properties of selective absorber coatings of a solar cooker have been investigated. Coatings have been prepared using soot from pine resin, wood stove and sugarcane, previously separated by size. Results show that the cooking power and the overall efficiency of these pots are higher than others painted with black primer. Besides, by using an integrating sphere, the diffuse reflectance of absorbers has been obtained. Lower values of the reflectance have been measured for the pots covered with soot, showing a high correlation with the results achieved from the thermal tests, considering the measurement errors.

  20. Structural and electrical characterization of NbO2 vertical devices grown on TiN coated SiO2/Si substrate

    NASA Astrophysics Data System (ADS)

    Joshi, Toyanath; Borisov, Pavel; Lederman, David

    Due to its relatively high MIT temperature (1081 K) and current-controlled negative differential resistance, NbO2 is a robust candidate for memory devices and electrical switching applications. In this work, we present in-depth analysis of NbO2 thin film vertical devices grown on TiN coated SiO2/Si substrates using pulsed laser deposition (PLD). Two of the films grown in 1 mTorr and 10 mTorr O2/Ar (~7% O2) mixed growth pressures were studied. The formation of NbO2 phase was confirmed by Grazing Incidence X-ray Diffractometry (GIXRD), X-ray Photoelectron Spectroscopy (XPS) and current vs. voltage measurements. A probe station tip (tip size ~2 μm) or conductive AFM tip was used as a top and TiN bottom layer was used as a bottom contact. Device conductivity showed film thickness and contact size dependence. Current pulse measurements, performed in response to applied triangular voltage pulses, showed a non-linear threshold switching behavior for voltage pulse durations of ~100 ns and above. Self-sustained current oscillations were analyzed in terms of defect density presented in the film. Supported by FAME (sponsored by MARCO and DARPA, Contract 2013-MA-2382), WV Higher Education Policy Commission Grant (HEPC.dsr.12.29), and WVU SRF. We also thank S. Kramer from Micron for providing the TiN-coated Si substrates.

  1. On-line defect detection of aluminum coating using fiber optic sensor

    NASA Astrophysics Data System (ADS)

    Patil, Supriya S.; Shaligram, A. D.

    2015-03-01

    Aluminum metallization using the sprayed coating for exhaust mild steel (MS) pipes of tractors is a standard practice for avoiding rusting. Patches of thin metal coats are prone to rusting and are thus considered as defects in the surface coating. This paper reports a novel configuration of the fiber optic sensor for on-line checking the aluminum metallization uniformity and hence for defect detection. An optimally chosen high bright 440 nm BLUE LED (light-emitting diode) launches light into a transmitting fiber inclined at the angle of 60° to the surface under inspection placed adequately. The reflected light is transported by a receiving fiber to a blue enhanced photo detector. The metallization thickness on the coated surface results in visually observable variation in the gray shades. The coated pipe is spirally inspected by a combination of linear and rotary motions. The sensor output is the signal conditioned and monitored with RISHUBH DAS. Experimental results show the good repeatability in the defect detection and coating non-uniformity measurement.

  2. Surface coating of graphene quantum dots using mussel-inspired polydopamine for biomedical optical imaging.

    PubMed

    Nurunnabi, Md; Khatun, Zehedina; Nafiujjaman, Md; Lee, Dong-geun; Lee, Yong-kyu

    2013-08-28

    Because of the superiority of GQDs (graphene quantum dots) in biomedical imaging, in terms of biocompatibility and toxicity of semiconductor quantum dots, GQDs bring new opportunities for the diagnosis and detection of diseases. In this study, we synthesized photoluminescent (PL) graphene quantum dots (GQDs) through a simple exfoliation and oxidation process, and then coated them with polydopamine (pDA) for enhanced stability in water and low toxicity in vivo. From the results, the GQDs coated with pDA showed an excellent stability of PL intensity. It showed that the PL intensity of noncoated GQDs in PBS solution rapidly decreased with time, resulting in a 45% reduction of the PL intensity for 14 days of incubation in PBS solution. After coating with polydopamine, PL intensities of polydopamine-coated GQDs was maintained more stably for 14 days compared with uncoated GQDs. We have observed the in vitro and in vivo biocompatibility of pDA-coated GQDs in nude mice. The overall observation revealed that pDA-coated GQDs could be used as a long-term optical imaging agent as well as a biocompatible drug carrier.

  3. Ex vivo optical characterization of in vivo grown tissues on dummy sensor implants using double integrating spheres measurement

    NASA Astrophysics Data System (ADS)

    Sharma, Sandeep; Goodarzi, Mohammad; Aernouts, Ben; Gellynck, Karolien; Vlaminck, Lieven; Bockstaele, Ronny; Cornelissen, Maria; Ramon, Herman; Saeys, Wouter

    2014-05-01

    Near infrared spectroscopy offers a promising technological platform for continuous glucose monitoring in the human body. NIR measurements can be performed in vivo with an implantable single-chip based optical NIR sensor. However, the application of NIR spectroscopy for accurate estimation of the analyte concentration in highly scattering biological systems still remains a challenge. For instance, a thin tissue layer may grow in the optical path of the sensor. As most biological tissues allow only a small fraction of the collimated light to pass, this might result in a large reduction of the light throughput. To quantify the effect of presence of a thin tissue layer in the optical path, the bulk optical properties of tissue samples grown on sensor dummies which had been implanted for several months in goats were characterized using Double Integrating Spheres and unscattered transmittance measurements. The measured values of diffuse reflectance, diffuse transmittance and collimated transmittance were used as input to Inverse Adding-Doubling algorithm to estimate the bulk optical properties of the samples. The estimates of absorption and scattering coefficients were then used to calculate the light attenuation through a thin tissue layer. Based on the lower reduction in unscattered transmittance and higher absorptivity of glucose molecules, the measurement in the combination band was found to be the better option for the implantable sensor. As the tissues were found to be highly forward scattering with very low unscattered transmittance, the diffuse transmittance measurement based sensor configuration was recommended for the implantable glucose sensor.

  4. Mechanical and optical characterization of tungsten oxynitride (W-O-N) nano-coatings

    NASA Astrophysics Data System (ADS)

    Nunez, Oscar Roberto

    Aation and cation doping of transition metal oxides has recently gained attention as a viable option to design materials for application in solar energy conversion, photo-catalysis, transparent electrodes, photo-electrochemical cells, electrochromics and flat panel displays in optoelectronics. Specifically, nitrogen doped tungsten oxide (WO3) has gained much attention for its ability to facilitate optical property tuning while also demonstrating enhanced photo-catalytic and photochemical properties. The effect of nitrogen chemistry and mechanics on the optical and mechanical properties of tungsten oxynitride (W-O-N) nano-coatings is studied in detail in this work. The W-O-N coatings were deposited by direct current (DC) sputtering to a thickness of ˜100 nm and the structural, compositional, optical and mechanical properties were characterized in order to gain a deeper understanding of the effects of nitrogen incorporation and chemical composition. All the W-O-N coatings fabricated under variable nitrogen gas flow rate were amorphous. X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectrometry (RBS) measurements revealed that nitrogen incorporation is effective only for a nitrogen gas flow rates ?9 sccm. Optical characterization using ultraviolet-visible-near infrared (UV-VIS-NIR) spectroscopy and spectroscopic ellipsometry (SE) indicate that the nitrogen incorporation induced effects on the optical parameters is significant. The band gap (Eg) values decreased from ˜2.99 eV to ˜1.89 eV indicating a transition from insulating WO3 to metallic-like W-N phase. Nano-mechanical characterization using indentation revealed a corresponding change in mechanical properties; maximum values of 4.46 GPa and 98.5 GPa were noted for hardness and Young?s modulus, respectively. The results demonstrate a clear relationship between the mechanical, physical and optical properties of amorphous W-O-N nano-coatings. The correlation presented in this thesis could

  5. Design and fabrication of stress-compensated optical coatings: Fabry-Perot filters for astronomical applications.

    PubMed

    de Denus-Baillargeon, Marie-Maude; Schmitt, Thomas; Larouche, Stéphane; Martinu, Ludvik

    2014-04-20

    The performance of optical coatings may be negatively affected by the deleterious effects of mechanical stress. In this work, we propose an optimization tool for the design of optical filters taking into account both the optical and mechanical properties of the substrate and of the individual deposited layers. The proposed method has been implemented as a supplemental module in the OpenFilters open source design software. It has been experimentally validated by fabricating multilayer stacks using e-beam evaporation, in combination with their mechanical stress assessment performed as a function of temperature. Two different stress-compensation strategies were evaluated: (a) design of two complementary coatings on either side of the substrate and (b) implementing the mechanical properties of the individual materials in the design of the optical coating on one side only. This approach has been tested by the manufacture of a Fabry-Perot etalon used in astronomy while using evaporated SiO2 and TiO2 films. We found that the substrate curvature can be decreased by 85% and 49% for the first and second strategies, respectively.

  6. Experimental demonstration of a Fresnel-reflection based optical fiber biosensor coated with polyelectrolyte multilayers

    NASA Astrophysics Data System (ADS)

    Yu, Wenjie; Lang, Tingting

    2014-11-01

    We report that the end facet of an optical fiber can be coated with polyelectrolyte multilayers (PEM) of polycation (diallyldimethyl ammonium chloride) and polyanion (styrenesulfonate sodium salt) (PDDA+PSS)n (n is the number of bilayers), which functions effectively as a Fresnel-reflection based biosensor. The experimental setup includes a broadband light source, a 3dB coupler, and an optical spectrum analyzer. Biotin and streptavidin are deposited onto the multilayers-coated end facet sequentially. The light intensity change due to variation of external refractive index is monitored. When the concentrations of streptavidin changes from 0.1mg/ml to 1mg/ml, a linear relationship between the concentration of streptavidin and the reflected optical power at the wavelength of 1530nm is observed. The sensitivity increases from -1.6262×10-3 dB/ppm to -4.7852 ×10-3 dB/ppm, when the number of PEM increases from 1 to 2. Then we confirm the optimized numbers of bilayers of PEM are 5 through experiment. Selectivity and repeatability of our proposed optical fiber biosensor are verified. When bovine serum albumin (BSA) is added instead of streptavidin, the obtained spectra overlaps with that of biotin's. The final end facet coated with PEM and biotin-streptavidin can be cleaned using microwave vibration or aqua regia. The microwave vibration method is utilized due to security concern. The optical spectra changes back to the initial one of the optical fiber in air. In conclusion, a Fresnel-reflection based optical fiber biosensor with good sensitivity, selectivity and repeatability is proposed. This biosensor has the advantages of simple structure, low cost and reliability.

  7. Robust optical properties of sandwiched lateral composition modulation GaInP structure grown by molecular beam epitaxy

    DOE PAGES

    Park, Kwangwook; Kang, Seokjin; Ravindran, Sooraj; ...

    2016-12-26

    Double-hetero structure lateral composition modulated (LCM) GaInP and sandwiched LCM GaInP having the same active layer thickness were grown and their optical properties were compared. Sandwiched LCM GaInP showed robust optical properties due to periodic potential nature of the LCM structure, and the periodicity was undistorted even for thickness far beyond the critical layer thickness. A thick LCM GaInP structure with undistorted potential that could preserve the properties of native LCM structure was possible by stacking thin LCM GaInP structures interspaced with strain compensating GaInP layers. Furthermore, the sandwiched structure could be beneficial in realizing the LCM structure embedded highmore » efficiency solar cells.« less

  8. Adsorbed Molecules and Surface Treatment Effect on Optical Properties of ZnO Nanowires Grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Jabri, S.; Souissi, H.; Sallet, V.; Lusson, A.; Meftah, A.; Galtier, P.; Oueslati, M.

    2017-07-01

    We have investigated the optical properties of ZnO nanowires grown by metalorganic chemical vapor deposition (MOCVD) with nitrous oxide (N2O) as oxygen precursor. Photoluminescence (PL) and Raman measurements showed the influence of adsorbed molecules on the optical properties. Low-temperature (4 K) PL studies on the surface exciton (SX) at 3.3660 eV elucidated the nature and origin of this emission. In particular, surface treatment by annealing at high temperature under inert gas reduced the emission intensity of SX. Raman vibrational spectra proved that presence of a considerable amount of adsorbed molecules on the surface of ZnO nanowires plays a key role in the occurrence of surface excitons.

  9. Robust optical properties of sandwiched lateral composition modulation GaInP structure grown by molecular beam epitaxy

    SciTech Connect

    Park, Kwangwook; Kang, Seokjin; Ravindran, Sooraj; Min, Jung-Wook; Hwang, Hyeong-Yong; Jho, Young-Dahl; Lee, Yong Tak

    2016-12-26

    Double-hetero structure lateral composition modulated (LCM) GaInP and sandwiched LCM GaInP having the same active layer thickness were grown and their optical properties were compared. Sandwiched LCM GaInP showed robust optical properties due to periodic potential nature of the LCM structure, and the periodicity was undistorted even for thickness far beyond the critical layer thickness. A thick LCM GaInP structure with undistorted potential that could preserve the properties of native LCM structure was possible by stacking thin LCM GaInP structures interspaced with strain compensating GaInP layers. The sandwiched structure could be beneficial in realizing the LCM structure embedded high efficiency solar cells.

  10. Effects of Mn dope on morphological, structural and optical properties of ZnO nanorods grown by a hydrothermal method

    NASA Astrophysics Data System (ADS)

    Putri, N. A.; Febrianti, Y.; Sugihartono, I.; Fauzia, V.; Handoko, D.

    2017-07-01

    ZnO nanorods were grown on glass substrate has been systematically investigated by varying Mn doping concentrations. The nanorods have been developed by a simple hydrothermal method on the ZnO seed layers which were deposited by ultrasonic spray pyrolysis method. The influences of Mn on the morphological, structural and optical behavior were observed by measuring Scanning Electron Microscope, X-Ray Diffraction, and UV-Vis spectrophotometer, respectively. It is found that the nanorods growth without any orientation. Interestingly, all the nanorods under investigated exhibit a polycrystalline hexagonal wurtzite structure with strong absorption in UV region and a high transparency in the visible region suggesting that optical properties of ZnO nanorods have been modified by Mn doping.

  11. Structural and optical characterization of ZrO2 thin films grown on silicon and quartz substrates

    NASA Astrophysics Data System (ADS)

    Hojabri, Alireza

    2016-09-01

    Zirconium oxide thin films were grown successfully by thermal annealing of zirconium thin films deposited on quartz and silicon substrates by direct current magnetron sputtering technique. The structural and optical properties in relation to thermal annealing times were investigated. The X-ray diffraction patterns revealed that structure of films changes from amorphous to crystalline by increase of annealing times in range 60-240 min. The composition of films was determined by Rutherford back scattering spectroscopy. Atomic force microscopy results exhibited that surface morphology and roughness of films depend on the annealing time. The refractive index of the films was calculated using Swanepoel's method. The optical band gap energy of annealed films decreased from 5.50 to 5.34 eV with increasing thermal annealing time.

  12. Electric, dielectric and optical properties of Ga2O3 grown by metal organic chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Paskaleva, A.; Spassov, D.; Terziyska, P.

    2017-01-01

    Thin film (15-130 nm) of gallium oxide were grown by the industry relevant metal organic chemical vapour deposition (MOCVD) technique on p-type Si to check the possibility for integration of newly rediscovered wide bandgap material with the Si technology. Electric, dielectric and optical properties were studied and analyzed. To perform electrical characterization, Ga2O3 films were integrated into Al/Ga2O3/p-Si metal–oxide–semiconductor (MOS) capacitors. Relative dielectric permittivity, flat-band voltage shift and effective oxide charge density were obtained from C-V measurements. Spectroscopic ellipsometry measurements reveal that Ga2O3 deposited by MOCVD is a direct bandgap material with a large optical bandgap of about 5.1 eV. Both ellipsometrical and electrical results show formation of a thick interfacial SiO2.

  13. Nonlinear optical studies of inorganic nanoparticles-polymer nanocomposite coatings fabricated by electron beam curing

    NASA Astrophysics Data System (ADS)

    Misra, Nilanjal; Rapolu, Mounika; Venugopal Rao, S.; Varshney, Lalit; Kumar, Virendra

    2016-05-01

    The optical nonlinearity of metal nanoparticles in dielectrics is of special interest because of their high polarizability and ultrafast response that can be utilized in potential device applications. In this study nanocomposite thin films containing in situ generated Ag nanoparticles dispersed in an aliphatic urethane acrylate (AUA) matrix were synthesized using electron beam curing technique, in presence of an optimized concentration of diluent Trimethylolpropanetriacrylate (TMPTA). The metal nanocomposite films were characterized using UV-visible spectrophotometry, transmission electron microscope (TEM) and field emission scanning electron microscope (FE-SEM) techniques. Ag nanoparticle impregnated films demonstrated an absorption peak at ∼420 nm whose intensity increased with increase in the Ag concentration. The optical limiting property of the coatings was tested using a nanosecond Nd-YAG laser operated at third harmonic wavelength of 355 nm. For a 25 ns pulse and 10 Hz cycle, Ag-polymer coatings showed good optical limiting property and the threshold fluence for optical limiting was found to be ∼3.8×10-2 J/cm2 while the transmission decreased to 82%. The nonlinear optical coefficients were also determined using the standard Z-scan technique with picosecond (∼2 ps, 1 kHz) and femtosecond (∼150 fs, 100 MHz) pulses. Open aperture Z-scan data clearly suggested two-photon absorption as the dominant nonlinear absorption mechanism. Our detailed studies suggest these composites are potential candidates for optical limiting applications.

  14. Microstructure and optical properties of Ge(Si) dots grown on Si

    NASA Astrophysics Data System (ADS)

    Wan, Jun; Tong, Song; Jiang, Zhimei; Jin, Gaolong; Luo, Y. H.; Liu, Jian-Lin; Liao, Xiaozhou; Zou, Jin; Wang, Kang L.

    2002-03-01

    The microstructural, luminescence properties and photoresponse of multilayer Ge(Si) quantum dots grown on Si (100) substrates are studied. The strain and composition of the dots are studied by synchrotron-radiation x-ray. The dots are found to be Si0.58Ge0.42 alloy with 50% strain relaxed in average. The photoluminescence from the dots is observed up to room temperature. The thermal stability of the quantum dots is studied. P-i-n structures are grown with Ge(Si) dots embedded in the i-layer for photodetection investigation. The photoresponse wavelength of Ge(Si) dots covers the wavelength range of 1.3-1.52 mm and relatively high external quantum efficiency is obtained.

  15. Study of the morphological, optical, structural and photoelectrochemical properties of TiO2 nanorods grown with various precursor concentrations

    NASA Astrophysics Data System (ADS)

    Choi, Hayoung; Ryu, Hyukhyun; Lee, Won-Jae

    2017-06-01

    Vertically aligned TiO2 nanorods were grown on a fluorine-doped tin oxide (FTO) substrate covered with a TiO2 buffer layer by using the hydrothermal method with various titanium precursor concentrations. In this study, the effects of the precursor concentration on the morphological, structural, optical and photoelectrochemical properties of TiO2 nanorods were investigated. We observed that photoelectrochemical properties were mainly dependent on the nanorod length, surface area, transmittance and (002) XRD peak intensity, which indicates the oriented growth of the TiO2 nanorods perpendicular to the substrate. As a result, the sample grown from a 0.09 M precursor solution, which grew vertically and had the highest surface area, showed the highest photocurrent density, 0.733 mA/cm2 (at 1.0 V vs. SCE). Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to characterize the morphology of the nanorods, X-ray diffraction (XRD) was used to detect the structural properties of the nanorods, UV-visual spectroscopy was used to measure the optical properties, and analysis with a three-electrode potentiostat was used to measure the photoelectrochemical properties. [Figure not available: see fulltext.

  16. Mirrors for High Resolution X-Ray Optics---Figure Preserving IR/PT Coating

    NASA Technical Reports Server (NTRS)

    Chan, Kai-Wing; Olsen, Lawrence; Sharpe, Marton; Numata, Ai; McClelland, Ryan; Saha, Timo; Zhang, Will

    2016-01-01

    Coating stress of 10 - 20 nm of Ir is sufficiently high to distort the figure of arc-second thin lightweight mirrors. For iridium: --Stress sigma 4 GPa for 15 nm film implies 60 Nm integrated stress-- Need less than 3 N/m (or stress less than 200 MPa) for sub-arcsecond optics. Basic Approaches for Mitigation. A. Annealing the film-- Glass can be heat up to 400 C without distortion. Silicon is even more resistant.-- It was found that recovery is limited by residual thermal stress from taking the mirror down from high T. B. Coating bi-layer films with compressive stress with tensile stress. C. Front-and-back coating with magnetron sputtering or atomic layer deposition-- Sputtering involve spanning of substrates. Geometric difference in setup (convexness/concaveness of curved mirrors) does not permit precise front-and-back matching-- Atomic layer deposition can provide a uniform deposition front and back simultaneously.

  17. High-refractive-index transparent coatings enhance the optical fiber cladding modes refractometric sensitivity.

    PubMed

    Renoirt, Jean-Michel; Zhang, Chao; Debliquy, Marc; Olivier, Marie-Georges; Mégret, Patrice; Caucheteur, Christophe

    2013-11-18

    The high order cladding modes of standard single mode optical fiber appear in quasi-degenerate pairs corresponding to mostly radially or mostly azimuthally polarized light. In this work, we demonstrate that, in the presence of a high-refractive-index coating surrounding the fiber outer surface, the wavelength spacing between the orthogonally polarized cladding modes families can be drastically enhanced. This behavior can be advantageously exploited for refractometric sensing purposes. For this, we make use of tilted fiber Bragg gratings (TFBGs) as spectral combs to excite the orthogonally polarized cladding modes families separately. TFBGs were coated with a nanometer-scale transparent thin film characterized by a refractive index value close to 1.9, well higher than the one of pure silica. This coating brings two important assets: an ~8-fold increase in refractometric sensitivity is obtained in comparison to bare TFBGs while the sensitivity is extended to surrounding refractive index (SRI) values above 1.45.

  18. Optical Fiber Nanotips Coated with Molecular Beacons for DNA Detection

    PubMed Central

    Giannetti, Ambra; Barucci, Andrea; Cosi, Franco; Pelli, Stefano; Tombelli, Sara; Trono, Cosimo; Baldini, Francesco

    2015-01-01

    Optical fiber sensors, thanks to their compactness, fast response and real-time measurements, have a large impact in the fields of life science research, drug discovery and medical diagnostics. In recent years, advances in nanotechnology have resulted in the development of nanotools, capable of entering the single cell, resulting in new nanobiosensors useful for the detection of biomolecules inside living cells. In this paper, we provide an application of a nanotip coupled with molecular beacons (MBs) for the detection of DNA. The MBs were characterized by hybridization studies with a complementary target to prove their functionality both free in solution and immobilized onto a solid support. The solid support chosen as substrate for the immobilization of the MBs was a 30 nm tapered tip of an optical fiber, fabricated by chemical etching. With this set-up promising results were obtained and a limit of detection (LOD) of 0.57 nM was reached, opening up the possibility of using the proposed nanotip to detect mRNAs inside the cytoplasm of living cells. PMID:25919369

  19. Study of properties of SiC layer in TRISO coated particles grown using different alkyl-silicon compounds

    NASA Astrophysics Data System (ADS)

    Prakash, Jyoti; Ghosh, Sunil; Venugopalan, Ramani; Sathiyamoorthy, D.

    2013-06-01

    The silicon carbide (SiC) layer used for the formation of Tri-isostatic (TRISO) coated fuel particles is normally produced at high temperatures via fluidized bed chemical vapor deposition from methyltrichlorosilane (MTS) in a hydrogen environment. In this work, we show the deposition of uniform SiC layers using different organosilicon precursors such as MTS and hexamethyldisilane (HMDS) via spouted bed chemical vapor deposition. From the X-ray diffraction pattern it could be inferred that the SiC deposits obtained through different precursors have the β-SiC phase. The microstructure and mechanical properties of the fabricated SiC coating were studied. The hardness and fracture toughness of the fabricated SiC coatings using MTS and HMDS were nearly the same and close to the theoretical value for pure silicon carbide.

  20. The influence of Er3+ doping on the structural and optical properties of CeO2 thin films grown by PED

    NASA Astrophysics Data System (ADS)

    Tatar, B.; Gökdemir, F. P.; Pehlivan, E.; Urgen, M.

    2013-11-01

    Erbium doped CeO2 thin films were deposited on both Corning glass substrates and indium doped tin oxide (ITO) coated glass substrates by pulsed e-beam deposition (PED) method at room temperature. Structural features of Er doped CeO2 thin films were studied with X-ray diffraction (XRD) and micro-Raman spectra. The XRD patterns of all films showed polycrystalline nature and cubic crystalline structure. Raman active peaks for both undoped CeO2 and Er doped CeO2 films were determined at ˜465 cm-1. The Raman shift observed in this study can also be assigned to Raman active modes of CeO2 that are shifted from the original position due to different doping concentration. The optical properties of CeO2 films and Er doped CeO2 films, which were determined from transmittance and reflectance measurements at room temperature, were very similar in character. The refractive indices and extinction coefficients, which were calculated from 3.5 to 1.25 eV (300-1000 nm), were between 1.5-3 and 0.05-0.2, respectively. The optical band gaps were deduced from the absorption coefficient according to solid band theory. The electrochromic measurements revealed that 2% Er doped CeO2 films grown on ITO + WO3 substrates had highest charge density compared to the other samples. Long-time cyclic voltammetry (CV) and chronoamperometry (CA) measurements were carried out to investigate the stability of this film.

  1. Injection moulding of optical functional micro structures using laser structured, PVD-coated mould inserts

    NASA Astrophysics Data System (ADS)

    Hopmann, Ch.; Weber, M.; Schöngart, M.; Schäfer, C.; Bobzin, K.; Bagcivan, N.; Brögelmann, T.; Theiß, S.; Münstermann, T.; Steger, M.

    2015-05-01

    Micro structured optical plastics components are intensively used i. e. in consumer electronics, for optical sensors in metrology, innovative LED-lighting or laser technology. Injection moulding has proven to be successful for the large-scale production of those parts. However, the production of those parts still causes difficulties due to challenges in the moulding and demoulding of plastics parts created with laser structured mould inserts. A complete moulding of the structures often leads to increased demoulding forces, which then cause a breaking of the structures and a clogging of the mould. An innovative approach is to combine PVD-coated (physical vapour deposition), laser structured inserts and a variothermal moulding process to create functional mic8iüro structures in a one-step process. Therefore, a PVD-coating is applied after the laser structuring process in order to improve the wear resistance and the anti-adhesive properties against the plastics melt. In a series of moulding trials with polycarbonate (PC) and polymethylmethacrylate (PMMA) using different coated moulds, the mould temperature during injection was varied in the range of the glass transition and the melt temperature of the polymers. Subsequently, the surface topography of the moulded parts is evaluated by digital 3D laser-scanning microscopy. The influence of the moulding parameters and the coating of the mould insert on the moulding accuracy and the demoulding behaviour are being analysed. It is shown that micro structures created by ultra-short pulse laser ablation can be successfully replicated in a variothermal moulding process. Due to the mould coating, significant improvements could be achieved in producing micro structured optical plastics components.

  2. Injection moulding of optical functional micro structures using laser structured, PVD-coated mould inserts

    SciTech Connect

    Hopmann, Ch.; Weber, M.; Schöngart, M.; Schäfer, C.; Bobzin, K.; Bagcivan, N.; Brögelmann, T.; Theiß, S.; Münstermann, T.; Steger, M.

    2015-05-22

    Micro structured optical plastics components are intensively used i. e. in consumer electronics, for optical sensors in metrology, innovative LED-lighting or laser technology. Injection moulding has proven to be successful for the large-scale production of those parts. However, the production of those parts still causes difficulties due to challenges in the moulding and demoulding of plastics parts created with laser structured mould inserts. A complete moulding of the structures often leads to increased demoulding forces, which then cause a breaking of the structures and a clogging of the mould. An innovative approach is to combine PVD-coated (physical vapour deposition), laser structured inserts and a variothermal moulding process to create functional mic8iüro structures in a one-step process. Therefore, a PVD-coating is applied after the laser structuring process in order to improve the wear resistance and the anti-adhesive properties against the plastics melt. In a series of moulding trials with polycarbonate (PC) and polymethylmethacrylate (PMMA) using different coated moulds, the mould temperature during injection was varied in the range of the glass transition and the melt temperature of the polymers. Subsequently, the surface topography of the moulded parts is evaluated by digital 3D laser-scanning microscopy. The influence of the moulding parameters and the coating of the mould insert on the moulding accuracy and the demoulding behaviour are being analysed. It is shown that micro structures created by ultra-short pulse laser ablation can be successfully replicated in a variothermal moulding process. Due to the mould coating, significant improvements could be achieved in producing micro structured optical plastics components.

  3. Improving optical transmission and image contrast in medium and high performance optical systems using weighted average angle of incidence techniques to optimize coatings

    NASA Astrophysics Data System (ADS)

    Harder, James A.; Sprague, Michaelene

    2008-10-01

    Designers of medium and high performance optical systems often overlook a very simple technique that can improve the system transmission and image contrast, as well as reduce scattering within the system. The resulting improvement in the optical collection efficiency can be used to increase performance or be traded off to realize improvements in other areas (i.e. aperture size, weight, etc.). The technique is based on the observation that many (if not most) anti-reflection coatings specified for lens surfaces, are specified at a normal angle of incidence. Since most of the energy incident on a typical lens impinges at angles other than the normal, the efficiency of an anti-reflection coating at any surface might be improved by using an approach based on weighted average angles of the incident radiation. This paper describes one approach to calculate weighted average coating angles for a optical systems. The optical transmissions are estimated, when the respective coatings are specified at the normal angle of incidence and at an angle based on the incident ray geometry. The measured transmission of two (otherwise identical) aspheric lenses, one coated using a standard SLAR coating specified at a normal incidence angle and the other coated using a standard SLAR coating specified at optimized incidence angles are presented.

  4. Optical design of COATLI: an all-sky robotic optical imager with 0.3 arcsec image quality

    NASA Astrophysics Data System (ADS)

    Fuentes-Fernández, Jorge; Cuevas, Salvador; Watson, Alan M.; Chapa, Oscar

    2016-08-01

    COATLI is a new instrument and telescope that will provide 0.3 arcsec FWHM images from 550 to 920 nm over a large fraction of the sky. It consists of a robotic 50-cm telescope with a diffraction-limited imager. The imager has a steering mirror for fast guiding, a blue channel using a EMCCD from 400 to 550 nm to measure image motion, a red channel using a standard CCD from 550 to 920 nm, and an active optics system based on a deformable mirror to compensate static aberrations in the red channel. Since the telescope is small, fast guiding will provide diffraction-limited image quality in the red channel over a large fraction of the sky, even in relatively poor seeing. COATLI will be installed at the Observatorio Astronomico Nacional in Baja California, Mexico, in September 2016 and will operate initially with a simple interim imager. The definitive COATLI instrument will be installed in 2017. In this paper, we present some of the details of the optical design of the instrument.

  5. Graphene coated fiber optic surface plasmon resonance biosensor for the DNA hybridization detection: Simulation analysis

    NASA Astrophysics Data System (ADS)

    Shushama, Kamrun Nahar; Rana, Md. Masud; Inum, Reefat; Hossain, Md. Biplob

    2017-01-01

    In this paper, a graphene coated optical fiber surface plasmon resonance (SPR) biosensor is presented for the detection of DNA Hybridization. For the proposed sensor, a four layer model (fiber core /metal /sensing layer /sample) where a sheet of graphene (biomolecular recognition elements (BRE)) acting as a sensing layer is coated around the gold film because graphene enhances the sensitivity of fiber optic SPR biosensor. Numerical analysis shows the variation of resonance wavelength and spectrum of transmitted power for mismatched DNA strands and for complementary DNA strands. For mismatched DNA strands variation is negligible whereas for complementary DNA strands is considerably countable. Proposed sensor successfully distinguishes hybridization and single nucleotide polymorphisms (SNP) by observing the variation level of resonance wavelength and spectrum of transmitted power.

  6. A device for applying plastic film antireflection coatings to optical elements

    NASA Technical Reports Server (NTRS)

    Augason, G. C.

    1984-01-01

    To simplify the process of thermally bonding thin plastic films to optical elements and to help eliminate the source of the flaws, a film-application device (FAD) is developed. Any plastic film may be used to make the coatings, but thin polyethylene is particularly useful for this application since it is readily available. If more than one layer of polyethylene is required, several layers may be applied, one layer at a time. The coatings may be used for protecting optical elements or to reduce surface reflection of radiation with wavelengths greater than 20 microns. When the FAD is used without the central plate it may be used to stretch single sheets of plastic material to make pellicles or beam-splitters for many applications.

  7. Optical coatings on glass for preserving artworks from illumination induced damage: design and testing

    NASA Astrophysics Data System (ADS)

    Farini, A.; Arrighi, R.; Di Sarcina, I.; Piegari, A. M.

    2005-06-01

    The deteriorating effect of light on artworks exposed in museums and galleries has been noticed for many years. A number of methods, which act on the illumination source, are presently in use to reduce the damage. A complementary approach is proposed here that consists in blocking the radiation, outside the range of sensitivity of the human eye, before it reaches the artwork. This result can be achieved by an optical coating deposited on the glass pane that is usually put in front of the artworks to protect them from vandalism. In addition to the preservation from illumination induced damage, the proposed coating is also able to improve the observation of the artwork by reducing the reflection effects of uncoated glass. Optical, colorimetric and psychophysical measurements on test samples are reported.

  8. High power coatings for line beam laser optics of up to 2-meter in length

    NASA Astrophysics Data System (ADS)

    Mende, Mathias; Kohlhaas, Jürgen; Ebert, Wolfgang

    2016-03-01

    Laser material processing plays an important role in the fabrication of the crucial parts for state-of-the-art smartphones and tablets. With industrial line beam systems a line shaped beam with a length above one meter and an average power of several thousand watts can be realized. To ensure excellent long axis beam homogeneity, demanding specifications regarding the substrate surface form tolerances and the coating uniformity have to be achieved for each line beam optic. In addition, a high laser damage threshold and a low defect density are required for the coatings. In order to meet these requirements, the MAXIMA ion beam sputtering machine was developed and built by LASEROPTIK. This contribution describes the functional principle of MAXIMA deposition machine, which adapts the ion beam sputtering technology with its highest coating quality to the field of large area deposition. Furthermore, recent developments regarding the process control by optical broadband monitoring are discussed. Finally experimental results on different thin film characteristics as for example the coating uniformity, the microstructure and the laser damage resistance of multilayers are presented.

  9. Measurement of adhesive forces between bacteria and protein-coated surfaces using optical tweezers

    NASA Astrophysics Data System (ADS)

    Simpson, Kathryn H.; Bowden, Gabriela; Hook, Magnus; Anvari, Bahman

    2002-05-01

    Bacterial adhesion is a primary cause of failure in implanted medical devices. Bacteria commonly found in device-related infections, such as S. aureus, have multiple cell surface adhesins which mediate specific adhesion to molecules found in extracellular matrix and blood plasma. Adhesins recognizing fibrinogen, fibronectin, collagen, and elastin molecules have been isolated in S. aureus. We have used optical tweezers to measure the adhesive force between a single bacterium and a protein-coated surface. Various concentrations of fibronectin, fibrinogen, or whole plasma were immobilized onto 10-micrometers diameter polystyrene microspheres. We optically trapped a bacterium with a titanium-sapphire laser tuned to 830 nm and contacted the cell with a coated bead. We determined the minimum force necessary to separate the cell and bead. For beads coated with fibronectin and fibrinogen, detachment force values occurred as approximate integer multiples of an estimated single bond detachment force. With plasma-coated beads, only cells lacking the fibrinogen adhesin could be detached; therefore, we believe that either this adhesin is prevalent on wilde-type cells, or it is preferentially adsorbed onto the beads. Additionally, the whole plasma detachment forces appeared random; therefore, we believe that many adhesins participate in boding to plasma.

  10. A novel perfluorinated AR (antireflective) and protective coating for KDP (potassium dihydrogen phosphate) and other optical materials

    SciTech Connect

    Thomas, I.M.; Campbell, J.H.

    1990-12-17

    A new commercially available perfluorinated organic polymer has been used to prepare a combined quarterwave AR and protective coating for KDP and other optical materials. Coatings are applied from solution at room temperature by spin or dip, they are fully dense and have a refractive index of 1.29. The laser damage threshold at 1064 nm and 355 nm is the highest that we have ever measured for an AR coating material. 5 refs., 8 figs., 3 tabs.

  11. Thin film NiTi coatings on optical fiber Bragg sensors

    SciTech Connect

    Mohanchandra, K. P.; Karnani, S.; Emmons, M. C.; Carman, G. P.; Richards, W. L.

    2008-07-21

    This paper describes the sputter deposition and characterization of nickel titanium (NiTi) thin film shape memory alloy onto the surface of an optical fiber Bragg grating. The NiTi coating uniformity, crystallinity, and transformation temperatures are measured using scanning electron microscope, x-ray diffraction, and differential scanning calorimeter, respectively. The strain in the optical fiber is measured using centroid calculation of wavelength shifts. Results show distinct and abrupt changes in the optical fiber signal with the four related transformation temperatures represented by the austenite-martensite forward and reverse phase transformations. These tests demonstrate a coupling present between optical energy and thermal energy, i.e., a modified multiferroic material.

  12. Fabrication of double layer optical tissue phantom by spin coating method: mimicking epidermal and dermal layer

    NASA Astrophysics Data System (ADS)

    Park, Jihoon; Bae, Yunjin; Bae, Youngwoo; Kang, Heesung; Lee, Kyoung-Joung; Jung, Byungjo

    2013-02-01

    Methodologies to fabricate a solid optical tissue phantom (OTP) mimicking epidermal thin-layer have been developed for in vitro human skin experiment. However, there are cumbersome and time-consuming efforts in fabrication process such as a custom-made casting and calculation of solvent volume before curing process. In a previous study, we introduced a new methodology based on spin coating method (SCM) which is utilized to fabricate a thin-layer OTP analogous to epidermal thickness. In this study, a double layer solid OTP which has epidermal and dermal layers was fabricated to mimic the morphological and optical similarity of human tissue. The structural characteristic and optical properties of fabricated double layer OTP were measured using optical coherence tomography and inverse adding doubling algorithms, respectively. It is expected that the new methodology based on the SCM may be usefully used in the fabrication of double layer OTP.

  13. Protective coating and hyperthermal atomic oxygen texturing of optical fibers used for blood glucose monitoring

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor)

    2008-01-01

    Disclosed is a method of producing cones and pillars on polymethylmethacralate (PMMA) optical fibers for glucose monitoring. The method, in one embodiment, consists of using electron beam evaporation to deposit a non-contiguous thin film of aluminum on the distal ends of the PMMA fibers. The partial coverage of aluminum on the fibers is randomly, but rather uniformly distributed across the end of the optical fibers. After the aluminum deposition, the ends of the fibers are then exposed to hyperthermal atomic oxygen, which oxidizes the areas that are not protected by aluminum. The resulting PMMA fibers have a greatly increased surface area and the cones or pillars are sufficiently close together that the cellular components in blood are excluded from passing into the valleys between the cones and pillars. The optical fibers are then coated with appropriated surface chemistry so that they can optically sense the glucose level in the blood sample than that with conventional glucose monitoring.

  14. Topical meeting on optical interference coatings (OIC'2001): design contest results.

    PubMed

    Thelen, Alfred; Tilsch, Markus; Tikhonravov, Alexander V; Trubetskov, Michael K; Brauneck, Ulf

    2002-06-01

    A gain-flattening filter (GFF) for minimum manufacturing errors (12 designs submitted) and dense wavelength-division multiplex (DWDM) filters for low group-delay (GD) variation (9 designs submitted) was the subject of a design contest held in conjunction with the Optical Interference Coatings 2001 topical meeting of the Optical Society of America. Results of the contest are given and evaluated. It turned out that the parameter space for GFFs with optimum performance when manufacturing errors are not considered is much different from that when manufacturing errors are considered. DWDM filter solutions with low GD variation are possible.

  15. Optical Interference Coatings Design Contest 2007: triple bandpass filter and nonpolarizing beam splitter.

    PubMed

    Tilsch, Markus; Hendrix, Karen

    2008-05-01

    A triple bandpass filter (28 solutions received) and a nonpolarizing beam splitter (23 solutions received) were the subjects of the design contest held in conjunction with the 2007 Optical Interference Coatings topical meeting of the Optical Society of America. Fifteen designers participated using a wide spectrum of design approaches and optimization strategies to create the submissions. The results differ significantly, but all meet the contest requirements. Fabien Lemarchand wins both contests by submitting the thinnest (6254 nm) triple bandpass design and the widest (61.7 nm) nonpolarizing beam-splitter design. Michael Trubetskov is in second place, followed by Vladimir Pervak in both contests. The submitted designs are described and evaluated.

  16. Optical field characteristics of nanofocusing by conical metal-coated dielectric probe.

    PubMed

    Tanaka, Kazuo; Katayama, Kiyofumi; Tanaka, Masahiro

    2011-10-10

    Nanofocusing of surface plasmon polariton by a conical metal-coated dielectric probe was investigated numerically using the three dimensional volume integral equation. The basic characteristics of the nanofocused optical fields generated by this probe were investigated in detail. The intensity distribution near the probe tip was found to be very sensitive to the shape of the probe tip. Enhanced local fields interfere near the tip for certain probe tip shapes.

  17. Optical coatings of variable refractive index and high laser-resistance from physical-vapor-deposited perfluorinated amorphous polymer

    DOEpatents

    Chow, Robert; Loomis, Gary E.; Thomas, Ian M.

    1999-01-01

    Variable index optical single-layers, optical multilayer, and laser-resistant coatings were made from a perfluorinated amorphous polymer material by physical vapor deposition. This was accomplished by physically vapor depositing a polymer material, such as bulk Teflon AF2400, for example, to form thin layers that have a very low refractive index (.about.1.10-1.31) and are highly transparent from the ultra-violet through the near infrared regime, and maintain the low refractive index of the bulk material. The refractive index can be varied by simply varying one process parameter, either the deposition rate or the substrate temperature. The thus forming coatings may be utilized in anti-reflectors and graded anti-reflection coatings, as well as in optical layers for laser-resistant coatings at optical wavelengths of less than about 2000 nm.

  18. Optical coatings of variable refractive index and high laser-resistance from physical-vapor-deposited perfluorinated amorphous polymer

    DOEpatents

    Chow, R.; Loomis, G.E.; Thomas, I.M.

    1999-03-16

    Variable index optical single-layers, optical multilayer, and laser-resistant coatings were made from a perfluorinated amorphous polymer material by physical vapor deposition. This was accomplished by physically vapor depositing a polymer material, such as bulk Teflon AF2400, for example, to form thin layers that have a very low refractive index (ca. 1.10--1.31) and are highly transparent from the ultra-violet through the near infrared regime, and maintain the low refractive index of the bulk material. The refractive index can be varied by simply varying one process parameter, either the deposition rate or the substrate temperature. The thus forming coatings may be utilized in anti-reflectors and graded anti-reflection coatings, as well as in optical layers for laser-resistant coatings at optical wavelengths of less than about 2000 nm. 2 figs.

  19. Dual-Clad (Coat) Pure Silica Optical Fibers For Biosensors/Endoscopes

    NASA Astrophysics Data System (ADS)

    Skutnik, Bolesh J.; Clarkin, James P.; Hille, Ronald E.

    1989-06-01

    The whole field of biosensing has been enhanced by the development of optical fibers CIA. They provide a means of activating the sensors and of carrying the sensor's signal back to the monitoring system. The small dimensions and flexibility of the fibers allow the development of the miniaturized sensor packages capable of introduction into a patient's vascular system. In a similar fashion optical fibers have revolutionized endoscopic techniques. Smaller, more flexible probes are permitting longer pathlengths and easier, less intrusive inspection of internal body areas. Standard fibers provide lighting while special optical fibers or bundles provide viewing capability. During the next decade real time sensing in vivo together with various endoscopic and laser techniques will provide doctors and patients with many new and delicate alternative procedures to common surgery. Not only will trauma be minimized, but with better and quicker knowledge of the patient's blood gas levels and other body conditions, doctors will be able to efficiently correct for unforeseen difficulties while controlling the known problems effectively. In both these application areas, the optimum fibers will need to have large numerical apertures (NA) to improve the sensing efficiency or the lighting efficiency and they must be sturdy/reliable as well as flexible. This places stringent requirements on the optical and mechanical porperties of the fibers. This paper describes a new type of fiber, Dual-Clad (Coat), High NA, Hard Clad Silica (HCS*) Fibers, which have the required optical and mechanical porperties for these application areas and very high core/clad/coat ratios.

  20. Optical Emission Spectroscopy in PECVD Helps Modulate Key Features in Biofunctional Coatings for Medical Implants

    NASA Astrophysics Data System (ADS)

    Santos, Miguel; Michael, Praveesuda; Filipe, Elysse; Wise, Steven; Bilek, Marcela; University of Sydney Collaboration

    2015-09-01

    We explore the use of optical emission spectroscopy (OES) diagnostic tools as a process feedback control strategy in plasma-assisted deposition of biofunctional coatings. Hydrogenated carbon nitride coatings are deposited on medical-grade metallic substrates using radio-frequency (rf) discharges sustained in C2H2/N2/Ar gaseous mixtures. The discharge is generated by capacitively coupling the rf power (supplied at f = 13.56 MHz) to the plasma and the substrates are electrically biased using a pulse generator to provide microsecond square profiled pulses at voltages in the range |Vbias| = 250 V - 1000 V. Nitrogen content and CN bonding configurations in the coatings follow similar trends to those of CN radicals and nitrogen molecular ions in the discharge. OES is used as a non-intrusive diagnostic technique to identify a suitable window of process parameters and ultimately achieve biofunctional interfaces compatible with current clinical demands. Importantly, we demonstrate that key features of the coatings can be modulated and made suitable for blood and/or tissue contacting medical implants, such as coronary stents and orthopaedic implants. The coatings are mechanically robust, inherently non-thrombogenic and can be readily modified, enabling an easy functionalization through the immobilization of biological molecules in a bioactive conformation.

  1. Optical Constants of Crystallized TiO2 Coatings Prepared by Sol-Gel Process

    PubMed Central

    Wang, Xiaodong; Wu, Guangming; Zhou, Bin; Shen, Jun

    2013-01-01

    Titanium oxide coatings have been deposited by the sol-gel dip-coating method. Crystallization of titanium oxide coatings was then achieved through thermal annealing at temperatures above 400 °C. The structural properties and surface morphology of the crystallized coatings were studied by micro-Raman spectroscopy and atomic force microscopy, respectively. Characterization technique, based on least-square fitting to the measured reflectance and transmittance spectra, is used to determine the refractive indices of the crystallized TiO2 coatings. The stability of the synthesized sol was also investigated by dynamic light scattering particle size analyzer. The influence of the thermal annealing on the optical properties was then discussed. The increase in refractive index with high temperature thermal annealing process was observed, obtaining refractive index values from 1.98 to 2.57 at He-Ne laser wavelength of 633 nm. The Raman spectroscopy and atomic force microscopy studies indicate that the index variation is due to the changes in crystalline phase, density, and morphology during thermal annealing. PMID:28811410

  2. Effects of dicarboxylic acid coating on the optical properties of soot.

    PubMed

    Xue, Huaxin; Khalizov, Alexei F; Wang, Lin; Zheng, Jun; Zhang, Renyi

    2009-09-28

    Soot is a major component of atmospheric aerosols responsible for absorption of visible solar radiation. Internal mixing of soot with transparent materials can enhance its ability to absorb and scatter light, resulting in a larger role of soot in climate forcing. We have investigated the absorption and scattering of visible light (532 nm) by soot aerosol internally mixed with succinic and glutaric acids using a combination of a cavity ring-down spectrometer and an integrating nephelometer. The measurements were performed for flame-generated soot aerosol with well-characterized morphology and mixing state in the particle size range from 155 to 320 nm. Thin coatings of dicarboxylic acids on soot aggregates (with a mass fraction of 0.1-0.4) enhance significantly light scattering (up to 3.8 fold) and slightly light absorption (less than 1.2 fold). Cycling the coated soot aerosol through high relative humidity (humidified to 90% RH and then dried to 5% RH) promotes further increase in light absorption and scattering for soot internally mixed with glutaric acid, but not for soot mixed with succinic acid. The larger effect of glutaric acid on light absorption and scattering is caused by the irreversible restructuring of soot aggregates induced by the coating material. Our results indicate that the enhancement in the optical properties of soot by transparent coatings is strongly related to the ability of the coating materials to change the morphology of soot aggregates.

  3. Optical spectroscopy of arsenic- and silver-containing sol-gel coatings

    NASA Astrophysics Data System (ADS)

    García, M. A.; Paje, S. E.; Llopis, J.; Villegas, M. A.; Fernández Navarro, J. M.

    1999-05-01

    Sol-gel silica coatings doped with 1 mol% silver and/or 1 mol% arsenic oxide have been investigated by photoluminescence (PL) and optical absorption (OA) spectroscopy. The presence of Ag+ ions in the silica host has been monitored by recording a luminescence peak located between 320 and 330 nm upon excitation with 228 nm light, whereas the formation of small particles of metallic silver has been assessed by recording the absorption band centred at about 405 nm. The luminescence peak has been related to the d10icons/Journals/Common/leftrightarrow" ALT="leftrightarrow" ALIGN="TOP"/>d9 s parity-forbidden transitions in Ag+, which are partially allowed by odd-phonon assistance. On the other hand, the absorption peak at about 405 nm arises from the well known surface-plasmon resonance of silver particles. Coating densification under various atmospheres gives rise to significant effects on the PL and OA spectra. Results indicate that, after coating densification in air, most of the silver appears as Ag+ ions, in contrast to coating densification under a 90% N2-10% H2 atmosphere, which favours the formation of small particles of metallic silver. The presence of arsenic oxide in the silver coatings densified in air has been found to improve the stabilization of Ag+ ions, so that partially prevents the formation of colloidal silver under reducing atmospheres.

  4. Comparisons between laser damage and optical electric field behaviors for hafnia/silica antireflection coatings

    SciTech Connect

    Bellum, John; Kletecka, Damon; Rambo, Patrick; Smith, Ian; Schwarz, Jens; Atherton, Briggs

    2011-03-20

    We compare designs and laser-induced damage thresholds (LIDTs) of hafnia/silica antireflection (AR) coatings for 1054 nm or dual 527 nm/1054 nm wavelengths and 0 deg. to 45 deg. angles of incidence (AOIs). For a 527 nm/1054 nm, 0 deg. AOI AR coating, LIDTs from three runs arbitrarily selected over three years are {approx}20 J/cm{sup 2} or higher at 1054 nm and <10 J/cm{sup 2} at 527 nm. Calculated optical electric field intensities within the coating show two intensity peaks for 527 nm but not for 1054 nm, correlating with the lower (higher) LIDTs at 527 nm (1054 nm). For 1054 nm AR coatings at 45 deg. and 32 deg. AOIs and S and P polarizations (Spol and Ppol), LIDTs are high for Spol (>35 J/cm{sup 2}) but not as high for Ppol (>30 J/cm{sup 2} at 32 deg. AOI; {approx}15 J/cm{sup 2} at 45 deg. AOI). Field intensities show that Ppol discontinuities at media interfaces correlate with the lower Ppol LIDTs at these AOIs. For Side 1 and Side 2 dual 527 nm/1054 nm AR coatings of a diagnostic beam splitter at 22.5 deg. AOI, Spol and Ppol LIDTs (>10 J/cm{sup 2} at 527 nm; >35 J/cm{sup 2} at 1054 nm) are consistent with Spol and Ppol intensity behaviors.

  5. Laser-induced damage thresholds of optical coatings at different temperature

    NASA Astrophysics Data System (ADS)

    Mikami, K.; Motokoshi, S.; Fujita, M.; Jitsuno, T.; Tanaka, K. A.

    2011-12-01

    Laser-induced damage thresholds for dielectric and metal single-layer coatings at different temperature conditions (123-473 K) were measured by 1064-nm wavelength and 4-ns pulses to elucidate the effects of initial temperature to laser damage mechanisms. SiO2, MgF2, gold, silver and copper single-layer coatings were prepared as experimental samples. In the experimental results, temperature dependence of LIDTs for optical substrates and all dielectric single-layer coatings indicated same trend as that for bulk silica glasses, which increased linearly with decreasing the temperature. However, all metallic coatings had the inverse trend of the dependence for dielectric coatings. The effects of initial temperature to laser damage mechanisms were considered with separated processes from the experimental results. In the conclusions, free-electron generation and electron multiple caused difficultly at low temperature and the laser-induced damage thresholds increased. On the other hand, plasma heating caused easily at low temperature and the laser-damage thresholds decreased.

  6. Optical and thermal properties of selective absorber coatings under CSP conditions

    NASA Astrophysics Data System (ADS)

    Macias, Juan Daniel; Herrera-Zamora, Dallely Melissa; Lizama-Tzec, Francisco Ivan; Bante-Guerra, Jose; Arés-Muzio, Oscar Eduardo; Oskam, Gerko; Rubio, Hernando Romero-Paredes; Alvarado-Gil, Juan Jose; Arancibia-Bulnes, Camilo; Ramos-Sánchez, Victor; Villafán-Vidales, Heidi Isabel

    2017-06-01

    Concentrating solar power (CSP) systems use solar absorbers to convert sunlight into thermal electric power. In CSP systems, a high reflective surface focuses sunlight onto a receiver that captures the solar energy and converts it into heat. The operation of high efficiency CSP systems involves improvements in the performance of the coatings of the solar absorption materials. To accomplish this, novel, more efficient selective coatings are being developed with high solar absorptance and low thermal losses at their operation temperature. Heat losses in a CSP system occur by three mechanisms: conduction, convection and radiation. It has been widely documented that energy losses increase with increasing operating temperature of CSP systems, and the precise knowledge of the thermophysical properties of the materials involved in CSP systems may allow us to increase the efficiency of systems. In this work, we applied the pulsed photoradiometry technique (PPTR) to evaluate the changes in the thermophysical properties of selective coatings on a variety of substrates as a function of temperature. Three types of coatings deposited with two different techniques on three types of substrate were examined: commercial coatings based on titanium oxynitride deposited by sputtering on substrates of copper and aluminum, coatings based on black nickel deposited by electrochemical methods on substrates of steel, and coatings based on black cobalt deposited by electrochemical methods on substrates of steel and copper. Values of the thermal diffusivity and thermal conductivity were obtained in the temperature range of 25 to 550 °C. Optical reflectance measurements have been performed in order to provide an estimate of the dependence of the thermal emittance on temperature using the black body radiation theory.

  7. Fabrication and characterization of replicated and lacquer-coated grazing incidence optics for X-ray astronomy

    NASA Technical Reports Server (NTRS)

    Ulmer, Melville P.; Haidle, R.; Altkorn, R.; Georgopoulos, P.; Rodricks, B.; Takacs, P. Z.

    1991-01-01

    The fabrication and testing of electroformed replica Wolter I optics made from gold-coated lacquered mandrels are discussed. Also discussed is the testing of gold- and palladium-coated lacquered test flats. X-ray (5 keV for Wolter I mirror and 8-40 keV for test flats) and optical (NCP-1000 profiler) measurements were used to evaluate the mirrors.

  8. Optical properties of PbS/CdS superlattices grown by pulsed laser evaporation

    NASA Astrophysics Data System (ADS)

    Musikhin, Sergey F.; Bakueva, Ludmila G.; Il'in, Vladimir I.; Rabizo, Oleg V.; Sharonova, Larissa V.

    1994-06-01

    PbS/CdS superlattices have been grown on BaF 2, CaF 2, Si and glass subtrates. Each specimen contained 10 to 23 pairs of the PbS/CdS layers. Absorption spectra of the structures have shown specific steps. The energy distribution of the steps has been analysed using models of Tipe-I and Tipe-II superlattices. Experimental results have been shown to follow the theoretical values of the steps for Tipe-II superlattices. This gives a foundation for classifying PbS/CdS superlattices as Tipe-II.

  9. Near-bandgap optical properties of pseudomorphic GeSn alloys grown by molecular beam epitaxy

    SciTech Connect

    D'Costa, Vijay Richard Wang, Wei; Yeo, Yee-Chia

    2016-08-14

    We investigated the compositional dependence of the near-bandgap dielectric function and the E{sub 0} critical point in pseudomorphic Ge{sub 1-x}Sn{sub x} alloys grown on Ge (100) substrate by molecular beam epitaxy. The complex dielectric functions were obtained using spectroscopic ellipsometry from 0.5 to 4.5 eV at room temperature. Analogous to the E{sub 1} and E{sub 1}+Δ{sub 1} transitions, a model consisting of the compositional dependence of relaxed alloys along with the strain contribution predicted by the deformation potential theory fully accounts for the observed compositional dependence in pseudomorphic alloys.

  10. Study on growth, structural, optical, thermal and mechanical properties of organic single crystal ethyl p-amino benzoate (EPAB) grown using vertical Bridgman technique

    NASA Astrophysics Data System (ADS)

    Muthuraja, A.; Kalainathan, S.

    2017-02-01

    Ethyl p-aminobenzoate (EPAB) single crystal was grown using vertical Bridgman technique (VBT). The crystal system of grown crystal was identified, and lattice parameters have been measured from the powder X-ray diffraction (PXRD). The optical transparency of EPAB single crystal was 55%, and the cut-off wavelength was found to be 337 nm. The thermal stability of EPAB single crystal was analyzed by thermogravimetric analysis. Etching studie were carried out for the grown crystal using different solvents, and etch pit density (EPD) was calculated and compared. Vickers microhardness (Hv) measurements revealed that EPAB belongs to the category of soft material. The dielectric studies reveal that the dielectric constant and dielectric loss of grown crystal decreases with increasing frequency for various temperatures. The third-order nonlinear optical property of EPAB was investigated and compared with other organic crystals. The evaluation of third-order optical properties such as nonlinear refractive index (n2), nonlinear absorption (β) and third-order nonlinear susceptibility (χ3) have found to be in the range of 10-11 m2/W, 10-4 m/W and 10-5 esu respectively. The Laser damage threshold energy of EPAB was measured using Nd: YAG laser. The blue emission of the grown crystal was identified by photoluminescence (PL) spectra measurements. The second harmonic generation (SHG) for the grown EPAB crystal was confirmed by Kurtz powder technique.

  11. Zinc oxide coated optical fiber long period gratings for sensing of volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Coelho, L.; Viegas, D.; Santos, J. L.; Martins de Almeida, José Manuel Marques

    2016-04-01

    The detection of volatile organic compounds is accomplished with a sensing device based on a long period fiber grating (LPFG) coated with a zinc oxide (ZnO) thin layer with self-temperature compensation. The ZnO coating structure was produced onto the cladding of the fiber by thermal oxidation of a metallic Zn thin film. The morphological characterization of ZnO thin films, grown at the same time on silicon substrates, was performed using X-ray diffraction, X-ray Photoelectron Spectroscopy and Scanning Electron Microscope which shows very good agreement. LPFGs with 290 nm thick ZnO coating were fabricated and characterized for the detection of ethanol and hexane in vapor phase. For ethanol a sensitivity of 0.99 nm / g.m-3 was achieved when using the wavelength shift interrogation mode, while for hexane a much lower sensitivity of 0.003 nm / g.m-3 was measured, indicating a semi-selectivity of the sensor with a spectral resolution better than 3.2 g.m-3.

  12. Grain structure and growth of dispersed phase BN-AlN coatings grown via chemical vapor deposition

    SciTech Connect

    Freeman, G.B.; Lackey, W.J.; Hanigofsky, J.A. . Georgia Technology Research Inst.); Lee, Woo Y. ); More, K.L. )

    1990-01-01

    This paper discusses the variation in microstructures encountered during the separate depositions of boron nitride (BN) and aluminium nitride (AlN) as well as during the codeposition of BN-AlN dispersed phase ceramic coatings. This combination was chosen in order to take advantage of the self lubricating properties of hexagonal BN along with the hard, erosion resistance of AlN. Films were characterized using scanning and transmission electron microscopy (SEM and TEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD). A range of coating microstructures are possible depending on the conditions of deposition. The best films produced, in terms of hardness, density, and tenacity, were a fine mixture of turbostratic BN and preferentially oriented A1N whiskers aligned with the whisker axis perpendicular to the substrate surface as seen by both electron microscopy and x-ray diffraction. 4 refs., 9 figs., 1 tab.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  14. Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition.

    PubMed

    Abou Chaaya, Adib; Viter, Roman; Bechelany, Mikhael; Alute, Zanda; Erts, Donats; Zalesskaya, Anastasiya; Kovalevskis, Kristaps; Rouessac, Vincent; Smyntyna, Valentyn; Miele, Philippe

    2013-01-01

    A study of transmittance and photoluminescence spectra on the growth of oxygen-rich ultra-thin ZnO films prepared by atomic layer deposition is reported. The structural transition from an amorphous to a polycrystalline state is observed upon increasing the thickness. The unusual behavior of the energy gap with thickness reflected by optical properties is attributed to the improvement of the crystalline structure resulting from a decreasing concentration of point defects at the growth of grains. The spectra of UV and visible photoluminescence emissions correspond to transitions near the band-edge and defect-related transitions. Additional emissions were observed from band-tail states near the edge. A high oxygen ratio and variable optical properties could be attractive for an application of atomic layer deposition (ALD) deposited ultrathin ZnO films in optical sensors and biosensors.

  15. Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition

    PubMed Central

    Abou Chaaya, Adib; Alute, Zanda; Erts, Donats; Zalesskaya, Anastasiya; Kovalevskis, Kristaps; Rouessac, Vincent; Smyntyna, Valentyn; Miele, Philippe

    2013-01-01

    Summary A study of transmittance and photoluminescence spectra on the growth of oxygen-rich ultra-thin ZnO films prepared by atomic layer deposition is reported. The structural transition from an amorphous to a polycrystalline state is observed upon increasing the thickness. The unusual behavior of the energy gap with thickness reflected by optical properties is attributed to the improvement of the crystalline structure resulting from a decreasing concentration of point defects at the growth of grains. The spectra of UV and visible photoluminescence emissions correspond to transitions near the band-edge and defect-related transitions. Additional emissions were observed from band-tail states near the edge. A high oxygen ratio and variable optical properties could be attractive for an application of atomic layer deposition (ALD) deposited ultrathin ZnO films in optical sensors and biosensors. PMID:24205465

  16. Deeply-etched micromirror with vertical slit and metallic coating enabling transmission-type optical MEMS filters

    NASA Astrophysics Data System (ADS)

    Othman, Muhammad A.; Sabry, Yasser M.; Sadek, Mohamed; Nassar, Ismail M.; Khalil, Diaa A.

    2016-03-01

    In this work we report a novel optical MEMS deeply-etched mirror with metallic coating and vertical slot, where the later allows reflection and transmission by the micromirror. The micromirror as well as fiber grooves are fabricated using deep reactive ion etching technology, where the optical axis is in-plane and the components are self-aligned. The etching depth is 150 μm chosen to improve the micromirror optical throughput. The vertical optical structure is Al metal coated using the shadow mask technique. A fiber-coupled Fabry-Pérot filter is successfully realized using the fabricated structure. Experimental measurements were obtained based on a dielectric-coated optical fiber inserted into a fiber groove facing the slotted micromirror. A versatile performance in terms of the free spectral range and 3-dB bandwidth is achieved.

  17. Piezoelectric InAs (211)B quantum dots grown by molecular beam epitaxy: Structural and optical properties

    SciTech Connect

    Dialynas, G. E.; Kalliakos, S.; Xenogianni, C.; Androulidaki, M.; Kehagias, T.; Komninou, P.; Savvidis, P. G.; Pelekanos, N. T.; Hatzopoulos, Z.

    2010-11-15

    The structural and optical properties of piezoelectric (211)B InAs nanostructures grown by molecular beam epitaxy are systematically investigated as a function of the various growth parameters. Depending on the specific growth conditions, we show that the InAs nanostructures take the form of a quantum dot (QD) or a quantum dash, their height ranges between 2 and 20 nm, and their density varies from a few times 10{sup 8} cm{sup -2} all the way up to a few times 10{sup 10} cm{sup -2}. The (211)B QDs are characterized by large aspect ratios, which are compatible with a truncated pyramid morphology. By analyzing the QD emission spectrum, we conclude that only small size QDs, with heights less than 3 nm, are optically active. This is consistent with high resolution transmission electron microscopy observations showing that large QDs contain misfit dislocations, whereas small QDs are dislocation-free. The formation of a two-dimensional wetting layer is observed optically, and its thickness is determined to be between 0.30 and 0.39 nm. Finally, the large blueshift in the QD emission observed with increasing excitation power represents a clear evidence of the strong built-in piezoelectric field present in these dots.

  18. Optical anisotropies of Si grown on step-graded SiGe(110) layers

    NASA Astrophysics Data System (ADS)

    Balderas-Navarro, R. E.; Lastras-Martínez, L. F.; Arimoto, K.; Castro-García, R.; Villalobos-Aguilar, O.; Lastras-Martínez, A.; Nakagawa, K.; Sawano, K.; Shiraki, Y.; Usami, N.; Nakajima, K.

    2010-03-01

    Macroreflectance and microreflectance difference spectroscopies have been used to measure the strain induced optical anisotropies of semiconductor structures comprised of strained Si(110) thin films deposited on top of step-graded SiGe virtual substrates. The stress relaxation mechanism mainly occurs by the introduction of microtwin formation, whose fluctuation depends strongly on growth conditions. Correlations of such optical diagnostics with x-ray diffraction measurements and atomic force microscopy images, allow for the in situ study of the strain within both the top Si layer and the SiGe underneath with an spatial resolution of at least 5 μm.

  19. Performance of multilayer optical coatings under long-term 532nm laser exposure

    NASA Astrophysics Data System (ADS)

    Poulios, D.; Konoplev, O.; Chiragh, F.; Vasilyev, A.; Stephen, M.; Strickler, K.

    2013-11-01

    The effects of long-term exposure to high intensity 532 nm radiation on various dielectric-coated optics are studied. To investigate potential photodarkening effects on optical surfaces, an accelerated life test platform was constructed where optics were exposed to 532 nm radiation from a short-pulse, high repetition rate fiber amplifier at total doses up to 1 trillion shots. The first run of trillion-shot tests were conducted on e-beam deposited and ion beam sputtering (IBS) coated high reflecting mirrors with onsurface intensities ranging from 1.0-1.4 GW/cm2. It was found that the e-beam coated mirrors failed catastrophically at less than 150 billion shots, while the IBS coated mirror was able to complete the trillionshot test with no measurable loss of reflectivity. Profiling the IBS mirror surface with a high-resolution white light interferometer post-irradiation revealed a ~10 nm high photocontamination deposit at the irradiation site that closely matched the intensity profile of the laser spot. Trillion-shot surface exposure tests were also conducted at multiple surface sites of an LBO frequency doubling crystal at ~1.5 GW/cm2 at multiple surface sites. The transmitted power and on-surface beam size were monitored throughout the tests, and periodic measurements of the beam quality and waist location of the transmitted light were also made using an M2 meter. No changes in transmitted power or M2 were observed in any of the tests, but 3D surface profiling revealed laser-induced contamination deposits at each site tested.

  20. Structural, optical, and electrical-transport properties of Al-P-O inorganic layer coated on flexible stainless steel substrate

    NASA Astrophysics Data System (ADS)

    Kim, Moojin; Min, Jinhyuk; Kwak, Yongsu; Kim, Doori; Kim, Kyoung-Bo; Song, Jonghyun

    2017-03-01

    We coated inorganic layer containing oxygen, aluminium, phosphorus, and negligible sodium (APO) on stainless steel (STS) by using slot-die coating method and studied its application prospects as a substrate for flexible devices. The APO layer was compositionally uniform in overall area with an amorphous crystal structure. Surface morphology characterization of STS exhibited an improved flatness after the APO layer coating process. The optical property characterization of the APO film carried out by measuring optical reflectance spectrum and refractive index. We also investigated the electrical-transport mechanism in the APO layer. These experimental observations imply the possibility of potential application of APO-STS as a substrate for flexible devices.

  1. TiO2 nanoparticle thin film-coated optical fiber Fabry-Perot sensor.

    PubMed

    Jiang, Mingshun; Li, Qiu-Shun; Wang, Jun-Nan; Jin, Zhongwei; Sui, Qingmei; Ma, Yaohong; Shi, Jianguo; Zhang, Faye; Jia, Lei; Yao, Wei-Guo; Dong, Wen-Fei

    2013-02-11

    In this paper, a novel TiO(2) nanoparticle thin film coated optical fiber Fabry-Perot (F-P) sensor had been developed for refractive index (RI) sensing by monitoring the shifts of the fringe contrast in the reflectance spectra. Using in situ liquid phase deposition approach, the TiO(2) nanoparticle thin film could be formed on the fiber surface in a controlled fashion. The optical properties of as-prepared F-P sensors were investigated both theoretically and experimentally. The results indicated that the RI sensitivity of F-P sensors could be effectively improved after the deposition of nanoparticle thin-films. It was about 69.38 dB/RIU, which was 2.6 times higher than that of uncoated one. The linear RI measurement range was also extended from 1.333~1.457 to 1.333~1.8423. More importantly, its optical properties exhibited the unique temperature-independent performance. Therefore, owing to these special optical properties, the TiO(2) nanoparticle thin film coated F-P sensors have great potentials in medical diagnostics, food quality testing, environmental monitoring, biohazard detection and homeland security, even at elevated temperature.

  2. Au3+ ion implantation on FTO coated glasses: Effect on structural, electrical, optical and phonon properties

    NASA Astrophysics Data System (ADS)

    Sahu, Bindu; Dey, Ranajit; Bajpai, P. K.

    2017-06-01

    Effects of 11.00 MeV Au3+ ions implanted in FTO coated (thickness ≈300 nm) silicate glasses on structural, electrical optical and phonon behavior have been explored. It has been observed that metal clustering near the surface and sub-surface region below glass-FTO interface changes electrical and optical properties significantly. Ion implantation does not affect the crystalline structure of the coated films; however, the unit cell volume decreases with increase in fluence and the tetragonal distortion (c/a ratio) also decreases systematically in the implanted samples. The sheet resistivity of the films increases from 11 × 10-5 ohm-cm (in pristine) to 7.5 × 10-4 ohm-cm for highest ion beam fluence ≈1015 ions/cm2. The optical absorption decreases with increasing fluence whereas, the optical transmittance as well as reflectance increases with increasing fluence. The Raman spectra are observed at ∼530 cm-1 and ∼1103 cm-1 in pristine sample. The broad band at 530 cm-1 shifts towards higher wave number in the irradiated samples. This may be correlated with increased disorder and strain relaxation in the samples as a result of ion beam irradiation.

  3. Electrical and optical properties of VO2 thin films grown on various sapphire substrates by using RF sputtering deposition

    NASA Astrophysics Data System (ADS)

    Jung, Dae Ho; So, Hyeon Seob; Ko, Kun Hee; Park, Jun Woo; Lee, Hosun; Nguyen, Trang Thi Thu; Yoon, Seokhyun

    2016-12-01

    VO2 thin films were grown on a-, c-, m-, and r-plane sapphire and SiO2/Si substrates under identical conditions by using RF sputtering deposition from a VO2 target. The structural and the morphological properties of all VO2 films were investigated. The grain sizes of the VO2 films varied between 268 nm and 355 nm depending on the substrate's orientation. The electrical and the optical properties of all VO2 thin films were examined in detail. The metal-insulator transition temperature (TMI) varied with the substrate's orientation. The (200)/(bar 211 )-oriented VO2 films on the a-plane sapphire showed the lowest TMI of about 329.3 K (56.3 °C) while the (020)/(002)-VO2 films on the c-plane sapphire displayed the highest TMI of about 339.6 K (66.6 °C). The VO2 films showed reversible changes in the resistivity as large as 1.19 × 105 and a hysteresis of 2 K upon traversing the transition temperature. The variations observed in the TMI with respect to the substrate's orientation were due to changes in the lattice strain and the grain size distribution. Raman spectroscopy showed that metal (rutile) - insulator (monoclinic) transitions occurred via the M2 phase for VO2 films on the c-plane substrate rather than the direct M1 to rutile transition. The shifts in the phonon frequencies of the VO2 film grown on various sapphire substrates were explained in terms of the strain along the V-V atomic bond direction (cR). Our work shows a possible correlation between the transition parameters ( e.g., TMI, sharpness, and hysteresis width) and the width ( σ) of the grain size distribution. It also shows a possible correlation between the TMI and the resistivities at the insulating and the metallic phases for VO2 films grown on various sapphire substrates.

  4. Optical Properties of LiNbO3 Single Crystal Grown by Czochralski Method

    NASA Astrophysics Data System (ADS)

    Sahar, M. R.; Naim, N. M.; Hamzah, K.

    2011-03-01

    Pure LiNbO3 single crystal was grown by Czochralski method using Automatic Diameter Control—Crystal Growth System (ADC-CGS). The transmission spectrum was determined by using Infrared Spectroscopy while the refractive index was determined using UV-Vis spectroscopy via the Sellmeier equation. The density was also measured using the Archimedes principle. It was found that the peak for the absorption vibrational spectrum for LiNbO3 crystal occurs at 801 cm-1, 672 cm-1, 639 cm-1 and 435 cm-1. The refractive index, ne was found to be 2.480 and the crystal density was around 4.64 g/cm3.

  5. Structural, Optical, and Electrical Characterization of Monoclinic β-Ga2O3 Grown by MOVPE on Sapphire Substrates

    NASA Astrophysics Data System (ADS)

    Tadjer, Marko J.; Mastro, Michael A.; Mahadik, Nadeemullah A.; Currie, Marc; Wheeler, Virginia D.; Freitas, Jaime A.; Greenlee, Jordan D.; Hite, Jennifer K.; Hobart, Karl D.; Eddy, Charles R.; Kub, Fritz J.

    2016-04-01

    Epitaxial growth of monoclinic β-Ga2O3 on a-plane and c-plane sapphire substrates by metalorganic vapor-phase epitaxy (MOVPE) is reported. Crystalline phase, growth rate (˜150 nm/h), and energy gap (˜4.7 eV) were determined by x-ray diffraction and optical reflectance measurements. Film density of ˜5.6 g/cm3 measured by x-ray reflectivity suggests the presence of vacancies, and the O-rich growth regime implies the presence of Ga vacancies in the films. O/Ga ratio of 1.13, as measured by XPS for Ga2O3 grown on c-plane Al2O3, suggests that, near the surface, the film is O-deficient. Atomic force microscopy revealed smoother, smaller grain size when films were grown on c-plane Al2O3. Raman spectroscopy suggested inclusions of α-Ga2O3, likely present at the sapphire interface due to growth on nonnative substrate. Samples of β-Ga2O3 were selectively implanted with Si in the source/drain regions and subsequently annealed at 1000°C for 10 min. Normally-off transistors (V T ≅ 4.7 V) with 20-nm-thick Al2O3 gate oxide were fabricated, and a maximum drain-source current of 4.8 nA was measured.

  6. Effect of lattice strain on structural and optical properties of ZnO nanorods grown by hydrothermal method

    SciTech Connect

    Gautam, Khyati Nirwal, Varun Singh; Singh, Joginder; Peta, Koteswara Rao; Bhatnagar, P. K.; Singh, Inderpreet

    2016-05-06

    In this work, we have synthesized ZnO nanorods over ZnO seeds/ITO/glass substrate by the facile hydrothermal method. ZnO seeds are grown at different temperatures ranging from 150°C to 550°C in steps of 100°C. We have studied the effect of strain on the structural and optical properties of ZnO nanorods. It was observed that the growth temperature of seed layer has an influence over the lattice strain present in the nanorods. The as synthesized nanorods were characterized by scanning electron microscope (SEM), x-ray diffraction (XRD) and photoluminescence (PL). SEM images confirm the formation of dense arrays of vertically aligned nanorods on seeds which are grown at 350°C. In addition to this, XRD patterns reveal that these ZnO nanorods are preferentially oriented along (002) direction. The strain analysis based on the XRD results reveals that the minimum value of strain is obtained at 350°C which is attributed to the improved crystalline quality of the interface of seed layer and nanorods leading to their c-axis alignment and enhancement of ultraviolet emission as observed in the PL spectra.

  7. Bandedge optical properties of MBE grown GaAsBi films measured by photoluminescence and photothermal deflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Beaudoin, M.; Lewis, R. B.; Andrews, J. J.; Bahrami-Yekta, V.; Masnadi-Shirazi, M.; O'Leary, S. K.; Tiedje, T.

    2015-09-01

    The bandedge optical properties of GaAsBi films, as thick as 470 nm, with Bi content varying from 0.7% Bi to 2.8% Bi grown by molecular beam epitaxy on GaAs substrates are measured by photoluminescence (PL) and photothermal deflection spectroscopy (PDS). The PDS spectra were fit with a modified Fernelius model which takes into account multiple reflections within the GaAsBi layer and GaAs substrate. Three undoped samples and two samples that are degenerately doped with silicon are studied. The undoped samples show a clear Urbach absorption edge with a composition dependent bandgap that decreases by 56 meV/% Bi and a composition independent Urbach slope parameter of 25 meV due to absorption by Bi cluster states near the valence band. The doped samples show a long absorption tail possibly due to absorption by gap states and free carriers in addition to a Burstein-Moss bandgap shift. PL of the undoped samples shows a lower energy emission peak due to defects not observed in the usually available thin samples (50 nm or less) grown under similar conditions.

  8. Annealing Effect on the Structural and Optical Properties of Sputter-Grown Bismuth Titanium Oxide Thin Films

    PubMed Central

    Alfonso, José E.; Olaya, Jhon J.; Bedoya-Hincapié, Claudia M.; Toudert, Johann; Serna, Rosalia

    2014-01-01

    The aim of this work is to assess the evolution of the structural and optical properties of BixTiyOz films grown by rf magnetron sputtering upon post-deposition annealing treatments in order to obtain good quality films with large grain size, low defect density and high refractive index similar to that of single crystals. Films with thickness in the range of 220–250 nm have been successfully grown. After annealing treatment at 600 °C the films show excellent transparency and full crystallization. It is shown that to achieve larger crystallite sizes, up to 17 nm, it is better to carry the annealing under dry air than under oxygen atmosphere, probably because the nucleation rate is reduced. The refractive index of the films is similar under both atmospheres and it is very high (n =2.5 at 589 nm). However it is still slightly lower than that of the single crystal value due to the polycrystalline morphology of the thin films. PMID:28788626

  9. Superconductivity in epitaxially grown self-assembled indium islands: progress towards hybrid superconductor/semiconductor optical sources

    SciTech Connect

    Gehl, Michael; Gibson, Ricky; Zandbergen, Sander; Keiffer, Patrick; Sears, Jasmine; Khitrova, Galina

    2016-02-01

    Currently, superconducting qubits lead the way in potential candidates for quantum computing. This is a result of the robust nature of superconductivity and the non-linear Josephson effect which make possible many types of qubits. At the same time, transferring quantum information over long distances typically relies on the use of photons as the elementary qubit. Converting between stationary electronic qubits in superconducting systems and traveling photonic qubits is a challenging yet necessary goal for the interface of quantum computing and communication. The most promising path to achieving this goal appears to be the integration of superconductivity with optically active semiconductors, with quantum information being transferred between the two by means of the superconducting proximity effect. Obtaining good interfaces between superconductor and semiconductor is the next obvious step for improving these hybrid systems. As a result, we report on our observation of superconductivity in self-assembled indium structures grown epitaxially on the surface of semiconductor material.

  10. Influence of Te doping on the dielectric and optical properties of InBi crystals grown by directional freezing

    NASA Astrophysics Data System (ADS)

    Ajayakumar, C. J.; Kunjomana, A. G.

    2014-05-01

    Stoichiometric pure and tellurium (Te) doped indium bismuthide (InBi) were grown using the directional freezing technique in a fabricated furnace. The X-ray diffraction profiles identified the crystallinity and phase composition. The surface topographical features were observed by scanning electron microscopy and atomic force microscopy. The energy dispersive analysis by X-rays was performed to identify the atomic proportion of elements. Studies on the temperature dependence of dielectric constant ( ɛ), loss tangent (tan δ), and AC conductivity ( σ ac) reveal the existence of a ferroelectric phase transition in the doped material at 403 K. When InBi is doped with tellurium (4.04 at%), a band gap of 0.20 eV can be achieved, and this is confirmed using Fourier transform infrared studies. The results thus show the conversion of semimetallic InBi to a semiconductor with the optical properties suitable for use in infrared detectors.

  11. Study of optical and structural properties of CZTS thin films grown by co-evaporation and spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Moreno, R.; Ramirez, E. A.; Gordillo Guzmán, G.

    2016-02-01

    Results regarding optical and structural properties of Cu2ZnSnS4 (CZTS) thin films prepared by co-evaporation using a novel procedure are compared with those obtained with CZTS films grown using a solution based route. The lattice strain ε and crystallite size D of CZTS films prepared by co-evaporation and by spray pyrolysis were estimated through X-ray diffraction (XRD) measurements using Williamson-Hall-isotropic strain model. The results of estimated average crystallite size of CZTS films by Scherrer and Williamson-Hall plot methods were compared with AFM (atomic force microscopy) measurements. It was found that the average crystallite size measured by Williamson-Hall plot methods agree quite well with AFM results. Further, information regarding the influence of preparation method on both, crystalline phases and the formation of structural defects was achieved through Raman and Urbach energy measurements.

  12. Structure and optical band gaps of (Ba,Sr)SnO{sub 3} films grown by molecular beam epitaxy

    SciTech Connect

    Schumann, Timo; Raghavan, Santosh; Ahadi, Kaveh; Kim, Honggyu; Stemmer, Susanne

    2016-09-15

    Epitaxial growth of (Ba{sub x}Sr{sub 1−x})SnO{sub 3} films with 0 ≤ x ≤ 1 using molecular beam epitaxy is reported. It is shown that SrSnO{sub 3} films can be grown coherently strained on closely lattice and symmetry matched PrScO{sub 3} substrates. The evolution of the optical band gap as a function of composition is determined by spectroscopic ellipsometry. The direct band gap monotonously decreases with x from to 4.46 eV (x = 0) to 3.36 eV (x = 1). A large Burnstein-Moss shift is observed with La-doping of BaSnO{sub 3} films. The shift corresponds approximately to the increase in Fermi level and is consistent with the low conduction band mass.

  13. Ga-related defect in as-grown Zn-doped GaN: An optically detected magnetic resonance study

    NASA Astrophysics Data System (ADS)

    Hai, P. N.; Chen, W. M.; Buyanova, I. A.; Monemar, B.; Amano, H.; Akasaki, I.

    2000-10-01

    A detailed study of as-grown Zn-doped GaN employing optically detected magnetic resonance (ODMR) spectroscopy is presented. Besides the well-known ODMR spectra of an effective-mass-like donor and Zn acceptor, a positive ODMR signal of an S=12 paramagnetic center was observed when monitoring the dominating blue luminescence band peaking at 2.8 eV. The involvement of a single Ga nucleus in the defect center is revealed from the rather well-resolved hyperfine interactions involving the isotopes 71Ga (39.9%) and 69Ga (60.1%), both with nuclear spin I=32. The C3v symmetry, the hyperfine interaction and the defect formation suggest a Ga-related complex nature of this center.

  14. Solution processable broadband transparent mixed metal oxide nanofilm optical coatings via substrate diffusion doping

    NASA Astrophysics Data System (ADS)

    Glynn, Colm; Aureau, Damien; Collins, Gillian; O'Hanlon, Sally; Etcheberry, Arnaud; O'Dwyer, Colm

    2015-11-01

    Devices composed of transparent materials, particularly those utilizing metal oxides, are of significant interest due to increased demand from industry for higher fidelity transparent thin film transistors, photovoltaics and a myriad of other optoelectronic devices and optics that require more cost-effective and simplified processing techniques for functional oxides and coatings. Here, we report a facile solution processed technique for the formation of a transparent thin film through an inter-diffusion process involving substrate dopant species at a range of low annealing temperatures compatible with processing conditions required by many state-of-the-art devices. The inter-diffusion process facilitates the movement of Si, Na and O species from the substrate into the as-deposited vanadium oxide thin film forming a composite fully transparent V0.0352O0.547Si0.4078Na0.01. Thin film X-ray diffraction and Raman scattering spectroscopy show the crystalline component of the structure to be α-NaVO3 within a glassy matrix. This optical coating exhibits high broadband transparency, exceeding 90-97% absolute transmission across the UV-to-NIR spectral range, while having low roughness and free of surface defects and pinholes. The production of transparent films for advanced optoelectronic devices, optical coatings, and low- or high-k oxides is important for planar or complex shaped optics or surfaces. It provides opportunities for doping metal oxides to ternary, quaternary or other mixed metal oxides on glass, encapsulants or other substrates that facilitate diffusional movement of dopant species.Devices composed of transparent materials, particularly those utilizing metal oxides, are of significant interest due to increased demand from industry for higher fidelity transparent thin film transistors, photovoltaics and a myriad of other optoelectronic devices and optics that require more cost-effective and simplified processing techniques for functional oxides and coatings

  15. NiCoO2 flowers grown on the aligned-flakes coated Ni foam for application in hybrid energy storage

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoyang; Zhao, Huilin; Zhou, JingKuo; Xue, Ruinan; Gao, Jianping

    2016-10-01

    Many NiCoO2 flowers with an average diameter of about 4 μm were grown on the NiCoO2 flakes coated Ni foam (denoted as NiCoO2/Ni foam) through a simple hydrothermal method and confirmed by scanning and transmission electron microscopies, X-ray diffraction and X-ray photoelectron spectrum measurements. The NiCoO2/Ni foam with high specific area and porosity was directly used as the working electrode without any binders. The measured specific capacitance of NiCoO2 grown on Ni foam is 756 F/g at 0.75 A/g using a three-electrode setup in 1 M KOH. Considering the high capacity of NiCoO2 and the good stability of rGO, the NiCoO2/Ni foam//rGO hybrid supercapacitor combining NiCoO2/Ni foam and rGO shows very good properties, such as high specific capacitance (82 F/g at 2 A/g based on the total mass of active materials), high energy density (25.7 Wh/kg at 1500 W/kg based on the total mass of active materials), good stability (about 90% capacitance retention after 2000-cycle at 100 mV/s), and low charge ion transfer resistance.

  16. Optical fiber pH sensor based on gold nanoparticles into polymeric coatings

    NASA Astrophysics Data System (ADS)

    Socorro, A. B.; Rivero, Pedro J.; Hernaez, M.; Goicoechea, J.; Matias, I. R.; Arregui, F. J.

    2015-05-01

    A pH optical fiber sensor based on electromagnetic resonances generated in a waveguide-nanocoating interface is presented here. The incorporation of gold nanoparticles (AuNPs) into polymeric thin films has been deeply studied and the deposition of these thin-films onto an optical fiber core has been performed in order to obtain a resonance-based optical fiber device. The presence of both the metal nanoparticles and the polymers in the coating allows the generation of two different electromagnetic resonances: localized surface plasmon resonance (LSPR) and lossy mode resonance (LMR). These phenomena can be simultaneously observed in the transmitted spectrum. The resultant device has shown a high sensitivity to pH changes from pH 4.0 to pH 6.0, with a large dynamical range and a very fast response.

  17. Structural, morphological and optical characterizations of ZnO:Al thin films grown on silicon substrates by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Alyamani, A.; Sayari, A.; Albadri, A.; Albrithen, H.; El Mir, L.

    2016-09-01

    The pulsed laser deposition (PLD) technique is used to grow Al-doped ZnO (AZO) thin films at 500 ° C on silicon substrates under vacuum or oxygen gas background from ablating AZO nanoparticle targets synthesized via the sol-gel process. The structural, morphological and optical properties were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and spectroscopic ellipsometry (SE) techniques. XRD and TEM images show that AZO powder has a wurtzite-type structure and is composed of small prismatic-like shape nanoparticles with an average size of 30nm. The structural properties of the AZO films grown under oxygen show no significant changes compared to those of the film grown under vacuum. However, the optical properties show a dependence on the growth conditions of the AZO films. Highly c -axis-oriented AZO thin films were obtained with grain size ˜ 15 nm. The stress in the AZO films is tensile as measured from the c -parameter. The dielectric function, the refractive index and the extinction coefficient as a function of the photon energy for the AZO films were determined by using spectroscopic ellipsometry measurements in the photon energy region from 1 to 6eV. The band gap energy was observed to slightly decrease in the presence of the O2 gas background and this may be attributed to the stress. The surface and volume energy loss functions are calculated and exhibit different behaviors in the energy range 1-6eV. Refractive indices of 1.9-2.1 in the visible region were obtained for the AZO films. Also, the electronic carrier concentration appears to be related to the presence of O2 during the growth process.

  18. Solution processable broadband transparent mixed metal oxide nanofilm optical coatings via substrate diffusion doping.

    PubMed

    Glynn, Colm; Aureau, Damien; Collins, Gillian; O'Hanlon, Sally; Etcheberry, Arnaud; O'Dwyer, Colm

    2015-12-21

    Devices composed of transparent materials, particularly those utilizing metal oxides, are of significant interest due to increased demand from industry for higher fidelity transparent thin film transistors, photovoltaics and a myriad of other optoelectronic devices and optics that require more cost-effective and simplified processing techniques for functional oxides and coatings. Here, we report a facile solution processed technique for the formation of a transparent thin film through an inter-diffusion process involving substrate dopant species at a range of low annealing temperatures compatible with processing conditions required by many state-of-the-art devices. The inter-diffusion process facilitates the movement of Si, Na and O species from the substrate into the as-deposited vanadium oxide thin film forming a composite fully transparent V0.0352O0.547Si0.4078Na0.01. Thin film X-ray diffraction and Raman scattering spectroscopy show the crystalline component of the structure to be α-NaVO3 within a glassy matrix. This optical coating exhibits high broadband transparency, exceeding 90-97% absolute transmission across the UV-to-NIR spectral range, while having low roughness and free of surface defects and pinholes. The production of transparent films for advanced optoelectronic devices, optical coatings, and low- or high-k oxides is important for planar or complex shaped optics or surfaces. It provides opportunities for doping metal oxides to ternary, quaternary or other mixed metal oxides on glass, encapsulants or other substrates that facilitate diffusional movement of dopant species.

  19. Optical properties of plasmon-resonant bare and silica-coated nanostars used for cell imaging.

    PubMed

    Bibikova, Olga; Popov, Alexey; Bykov, Alexander; Prilepskii, Artur; Kinnunen, Matti; Kordas, Krisztian; Bogatyrev, Vladimir; Khlebtsov, Nikolai; Vainio, Seppo; Tuchin, Valery

    2015-07-01

    We synthesized and characterized gold nanostars and their silica-coated derivatives with 7- to 50-nm shell thicknesses as contrast agents for optical imaging. The scattering and absorption coefficients of the nanoparticles (NPs) were estimated by means of collimated transmittance and diffuse reflectance/transmittance analyses. The contrasting properties of the nanostructures were studied in optical coherence tomography glass capillary imaging. The silica-coated nanostars with the thickest shell have higher scattering ability in comparison with bare nanostars. Viability assays confirmed weak in vitro toxicity of nanostructures at up to ∼200-μg/mL concentrations. We showed real-time visualization of nanostars in both agarose and cultured cells by analyzing the backscattering signal using a conventional laser confocal microscope. The signal intensity detected from the silica-coated NPs was almost 1.5 times higher in comparison with bare nanostars. To the best of our knowledge, this is the first time that conventional laser confocal microscopy was applied in combined scattering and transmitted light modes to detect the backscattered signal of gold nanostars, which is useful for direct monitoring of the uptake, translocation, and accumulation of NPs in living cells.

  20. Optical breathing of nano-porous antireflective coatings through adsorption and desorption of water

    PubMed Central

    Nielsen, Karsten H.; Kittel, Thomas; Wondraczek, Katrin; Wondraczek, Lothar

    2014-01-01

    We report on the direct consequences of reversible water adsorption on the optical performance of silica-based nanoporous antireflective (AR) coatings as they are applied on glass in photovoltaic and solar thermal energy conversion systems. In situ UV-VIS transmission spectroscopy and path length measurements through high-resolution interferometric microscopy were conducted on model films during exposure to different levels of humidity and temperature. We show that water adsorption in the pores of the film results in a notable increase of the effective refractive index of the coating. As a consequence, the AR effect is strongly reduced. The temperature regime in which the major part of the water can be driven-out rapidly lies in the range of 55°C and 135°C. Such thermal desorption was found to increase the overall transmission of a coated glass by ~ 1%-point. As the activation energy of isothermal desorption, we find a value of about 18 kJ/mol. Within the experimental range of our data, the sorption and desorption process is fully reversible, resulting in optical breathing of the film. Nanoporous AR films with closed pore structure or high hydrophobicity may be of advantage for maintaining AR performance under air exposure. PMID:25307536

  1. Optical breathing of nano-porous antireflective coatings through adsorption and desorption of water

    NASA Astrophysics Data System (ADS)

    Nielsen, Karsten H.; Kittel, Thomas; Wondraczek, Katrin; Wondraczek, Lothar

    2014-10-01

    We report on the direct consequences of reversible water adsorption on the optical performance of silica-based nanoporous antireflective (AR) coatings as they are applied on glass in photovoltaic and solar thermal energy conversion systems. In situ UV-VIS transmission spectroscopy and path length measurements through high-resolution interferometric microscopy were conducted on model films during exposure to different levels of humidity and temperature. We show that water adsorption in the pores of the film results in a notable increase of the effective refractive index of the coating. As a consequence, the AR effect is strongly reduced. The temperature regime in which the major part of the water can be driven-out rapidly lies in the range of 55°C and 135°C. Such thermal desorption was found to increase the overall transmission of a coated glass by ~ 1%-point. As the activation energy of isothermal desorption, we find a value of about 18 kJ/mol. Within the experimental range of our data, the sorption and desorption process is fully reversible, resulting in optical breathing of the film. Nanoporous AR films with closed pore structure or high hydrophobicity may be of advantage for maintaining AR performance under air exposure.

  2. Improvement of the Thermal and Optical Performances of Protective Polydimethylsiloxane Space Coatings with Cellulose Nanocrystal Additives.

    PubMed

    Planes, Mikael; Brand, Jérémie; Lewandowski, Simon; Remaury, Stéphanie; Solé, Stéphane; Le Coz, Cédric; Carlotti, Stéphane; Sèbe, Gilles

    2016-10-07

    This work investigates the possibility of using cellulose nanocrystals (CNCs) as biobased nanoadditives in protective polydimethylsiloxane (PDMS) space coatings, to improve the thermal and optical performances of the material. CNCs produced from wood pulp were functionalized in different conditions with the objective to improve their dispersibility in the PDMS matrix, increase their thermal stability and provide photoactive functions. Polysiloxane, cinnamate, chloroacetate and trifluoroacetate moieties were accordingly anchored at the CNCs surface by silylation, using two different approaches, or acylation with different functional vinyl esters. The modified CNCs were thoroughly characterized by FT-IR spectroscopy, solid-state NMR spectroscopy and thermogravimetric analysis, before being incorporated into a PDMS space coating formulation in low concentration (0.5 to 4 wt %). The cross-linked PDMS films were subsequently investigated with regards to their mechanical behavior, thermal stability and optical properties after photoaging. Results revealed that the CNC additives could significantly improve the thermal stability of the PDMS coating, up to 140 °C, depending on the treatment and CNC concentration, without affecting the mechanical properties and transparency of the material. In addition, the PDMS films loaded with as low as 1 wt % halogenated nanoparticles, exhibited an improved UV-stability after irradiation in geostationary conditions.

  3. Temperature driven evolution of thermal, electrical, and optical properties of Ti–Al–N coatings

    PubMed Central

    Rachbauer, Richard; Gengler, Jamie J.; Voevodin, Andrey A.; Resch, Katharina; Mayrhofer, Paul H.

    2012-01-01

    Monolithic single phase cubic (c) Ti1−xAlxN thin films are used in various industrial applications due to their high thermal stability, which beneficially effects lifetime and performance of cutting and milling tools, but also find increasing utilization in electronic and optical devices. The present study elucidates the temperature-driven evolution of heat conductivity, electrical resistivity and optical reflectance from room temperature up to 1400 °C and links them to structural and chemical changes in Ti1−xAlxN coatings. It is shown that various decomposition phenomena, involving recovery and spinodal decomposition (known to account for the age hardening phenomenon in c-Ti1−xAlxN), as well as the cubic to wurtzite phase transformation of spinodally formed AlN-enriched domains, effectively increase the thermal conductivity of the coatings from ∼3.8 W m−1 K−1 by a factor of three, while the electrical resistivity is reduced by one order of magnitude. A change in the coating color from metallic grey after deposition to reddish-golden after annealing to 1400 °C is related to the film structure and discussed in terms of film reflectivity. PMID:23482424

  4. Temperature driven evolution of thermal, electrical, and optical properties of Ti-Al-N coatings.

    PubMed

    Rachbauer, Richard; Gengler, Jamie J; Voevodin, Andrey A; Resch, Katharina; Mayrhofer, Paul H

    2012-03-01

    Monolithic single phase cubic (c) Ti1-x Al x N thin films are used in various industrial applications due to their high thermal stability, which beneficially effects lifetime and performance of cutting and milling tools, but also find increasing utilization in electronic and optical devices. The present study elucidates the temperature-driven evolution of heat conductivity, electrical resistivity and optical reflectance from room temperature up to 1400 °C and links them to structural and chemical changes in Ti1-x Al x N coatings. It is shown that various decomposition phenomena, involving recovery and spinodal decomposition (known to account for the age hardening phenomenon in c-Ti1-x Al x N), as well as the cubic to wurtzite phase transformation of spinodally formed AlN-enriched domains, effectively increase the thermal conductivity of the coatings from ∼3.8 W m(-1) K(-1) by a factor of three, while the electrical resistivity is reduced by one order of magnitude. A change in the coating color from metallic grey after deposition to reddish-golden after annealing to 1400 °C is related to the film structure and discussed in terms of film reflectivity.

  5. Optical properties of plasmon-resonant bare and silica-coated nanostars used for cell imaging

    NASA Astrophysics Data System (ADS)

    Bibikova, Olga; Popov, Alexey; Bykov, Alexander; Prilepskii, Artur; Kinnunen, Matti; Kordas, Krisztian; Bogatyrev, Vladimir; Khlebtsov, Nikolai; Vainio, Seppo; Tuchin, Valery

    2015-07-01

    We synthesized and characterized gold nanostars and their silica-coated derivatives with 7- to 50-nm shell thicknesses as contrast agents for optical imaging. The scattering and absorption coefficients of the nanoparticles (NPs) were estimated by means of collimated transmittance and diffuse reflectance/transmittance analyses. The contrasting properties of the nanostructures were studied in optical coherence tomography glass capillary imaging. The silica-coated nanostars with the thickest shell have higher scattering ability in comparison with bare nanostars. Viability assays confirmed weak in vitro toxicity of nanostructures at up to ˜200-μg/mL concentrations. We showed real-time visualization of nanostars in both agarose and cultured cells by analyzing the backscattering signal using a conventional laser confocal microscope. The signal intensity detected from the silica-coated NPs was almost 1.5 times higher in comparison with bare nanostars. To the best of our knowledge, this is the first time that conventional laser confocal microscopy was applied in combined scattering and transmitted light modes to detect the backscattered signal of gold nanostars, which is useful for direct monitoring of the uptake, translocation, and accumulation of NPs in living cells.

  6. Graphene grown on stainless steel as a high-performance and ecofriendly anti-corrosion coating for polymer electrolyte membrane fuel cell bipolar plates

    NASA Astrophysics Data System (ADS)

    Pu, Nen-Wen; Shi, Gia-Nan; Liu, Yih-Ming; Sun, Xueliang; Chang, Jeng-Kuei; Sun, Chia-Liang; Ger, Ming-Der; Chen, Chun-Yu; Wang, Po-Chiang; Peng, You-Yu; Wu, Chia-Hung; Lawes, Stephen

    2015-05-01

    In this study, the growth of graphene by chemical vapor deposition (CVD) on SUS304 stainless steel and on a catalyzing Ni/SUS304 double-layered structure was investigated. The results indicated that a thin and multilayered graphene film can be continuously grown across the metal grain boundaries of the Ni/SUS304 stainless steel and significantly enhance its corrosion resistance. A 3.5 wt% saline polarization test demonstrated that the corrosion currents in graphene-covered SUS304 were improved fivefold relative to the corrosion currents in non-graphene-covered SUS304. In addition to enhancing the corrosion resistance of stainless steel, a graphene coating also ameliorates another shortcoming of stainless steel in a corrosive environment: the formation of a passive oxidation layer on the stainless steel surface that decreases conductivity. After a corrosion test, the graphene-covered stainless steel continued to exhibit not only an excellent low interfacial contact resistance (ICR) of 36 mΩ cm2 but also outstanding drainage characteristics. The above results suggest that an extremely thin, lightweight protective coating of graphene on stainless steel can act as the next-generation bipolar plates of fuel cells.

  7. Carbon Nanofiber Arrays Grown on Three-Dimensional Carbon Fiber Architecture Substrate and Enhanced Interface Performance of Carbon Fiber and Zirconium Carbide Coating.

    PubMed

    Yan, Liwen; Zhang, Xinghong; Hu, Ping; Zhao, Guangdong; Dong, Shun; Liu, Dazhao; Sun, Boqian; Zhang, Dongyang; Han, Jiecai

    2017-05-24

    Carbon nanofibers (CNFs) were grown around the carbon fiber architecture through a plasma enhanced chemical vapor deposition method to enhance the interface performance between CF architecture substrate and ZrC preceramic matrix. The synthesized 3D CF hierarchical architectures (CNFs-CF) are coated with zirconium carbide (ZrC) ceramic to enhance their antioxidant property and high temperature resistance. The composition and the crystalline phase structure of the composite were detected with the X-ray photoelectron spectroscopy and X-ray diffraction. The results of scanning electron microscopy show that, the as-prepared CNFs and consistent ZrC ceramic coating are uniformly covered on the surface of carbon fiber architecture substrate. The ZrC ceramic products with excellent crystallinity were got from the pyrolysis of preceramic polymer at 1600 °C in inert atmosphere. Comparing with the untreated CF, the loading of ZrC ceramics around the CNFs-CF architecture surface are significantly increased. The thermal stability and mechanical property of CNFs-CF/ZrC nanocomposites have been promoted obviously compared with the CF/ZrC ceramic nanocomposite. The prepared CNFs-CF/ZrC ceramic nanocomposite is one of the potential candidate materials for the thermal protection application.

  8. Models for the optical simulations of fractal aggregated soot particles thinly coated with non-absorbing aerosols

    NASA Astrophysics Data System (ADS)

    Wu, Yu; Cheng, Tianhai; Zheng, Lijuan; Chen, Hao

    2016-10-01

    Light absorption enhancement of aged soot aerosols is highly sensitive to the morphologies and mixing states of soot aggregates and their non-absorbing coatings, such as organic materials. The quantification of these effects on the optical properties of thinly coated soot aerosols is simulated using an effective model with fixed volume fractions. Fractal aggregated soot was simulated using the diffusion limited aggregation (DLA) algorithm and discretized into soot dipoles. The dipoles of non-absorbing aerosols, whose number was fixed by the volume fraction, were further generated from the neighboring random edge dipoles. Their optical properties were calculated using the discrete dipole approximation (DDA) method and were compared with other commonly used models. The optical properties of thinly coated soot calculated using the fixed volume fraction model are close to (less than ~10% difference) the results of the fixed coating thickness model, except their asymmetry parameters (up to ~25% difference). In the optical simulations of thinly coated soot aerosols, this relative difference of asymmetry parameters and phase functions between these realistic models may be notable. The realizations of the fixed volume fraction model may introduce smaller variation of optical results than those of the fixed coating thickness model. Moreover, the core-shell monomers model and homogeneous aggregated spheres model with the Maxwell-Garnett (MG) theory may underestimate (up to ~20%) the cross sections of thinly coated soot aggregates. The single core-shell sphere model may largely overestimate (up to ~150%) the cross sections and single scattering albedo of thinly coated soot aggregates, and it underestimated (up to ~60%) their asymmetry parameters. It is suggested that the widely used single core-shell sphere approximation may not be suitable for the single scattering calculations of thinly coated soot aerosols.

  9. Thermomechanical model to assess stresses developed during elevated-temperature cleaning of coated optics.

    PubMed

    Liddell, H P H; Lambropoulos, J C; Jacobs, S D

    2014-09-10

    A thermomechanical model is developed to estimate the stress response of an oxide coating to elevated-temperature chemical cleaning. Using a hafnia-silica multilayer dielectric pulse compressor grating as a case study, we demonstrate that substrate thickness can strongly affect the thermal stress response of the thin-film coating. As a result, coatings on large, thick substrates may be susceptible to modes of stress-induced failure (crazing or delamination) not seen in small parts. We compare the stress response of meter-scale optics to the behavior of small-scale test or "witness" samples, which are expected to be representative of their full-size counterparts. The effects of materials selection, solution temperature, and heating/cooling rates are explored. Extending the model to other situations, thermal stress results are surveyed for various combinations of commonly used materials. Seven oxide coatings (hafnia, silica, tantala, niobia, alumina, and multilayers of hafnia-silica and alumina-silica) and three glass substrates (BK7, borosilicate float glass, and fused silica) are examined to highlight some interesting results.

  10. Tailoring the optical and hydrophobic property of zinc oxide nanorod by coating with amorphous graphene

    NASA Astrophysics Data System (ADS)

    Pahari, D.; Das, N. S.; Das, B.; Chattopadhyay, K. K.; Banerjee, D.

    2016-09-01

    Zinc oxide (ZnO) nanorods were synthesized at room temperature on potassium permanganate activated silicon and glass substrate by simple chemical method using zinc acetate as precursor. To modify the surface energy of the as prepared ZnO thin films the samples were coated with amorphous graphene (a-G) synthesized by un-zipping of chemically synthesized amorphous carbon nanotubes (a-CNTs). All the pure and coated samples were characterized by x-ray diffraction, field emission scanning electron microscope, Raman spectroscopy, and Fourier transformed infrared spectroscopy. The roughness analysis of the as prepared samples was done by atomic force microscopic analysis. The detail optical properties of all the samples were studied with the help of a UV-Visible spectrophotometer. The surface energy of the as prepared pure and coated samples was calculated by measuring the contact angle of two different liquids. It is seen that the water repellence of ZnO nanorods got increased after they are being coated with a-Gs. Also even after UV irradiation the contact angle remain same unlike the case for the uncoated sample where the contact angle gets decreased significantly after UV irradiation. Existing Cassie-Wenzel model has been employed along with the Owen's approach to determine the different components of surface energy.

  11. Magneto-optical magnetometry of individual 30 nm cobalt nanowires grown by electron beam induced deposition

    SciTech Connect

    Nikulina, E.; Idigoras, O.; Berger, A.; Vavassori, P.; Chuvilin, A.

    2012-04-02

    We show that magnetometry measurements based upon the magneto-optical Kerr effect and high resolution optical microscopy can be used as a noninvasive probe of magnetization reversal for individual nano-structures. Our measurements demonstrate single pass hysteresis loop measurements for sample sizes down to 30 nm width. A quantitative signal-to-noise ratio evaluation shows that our approach achieves an at least 3-fold improvement in sensitivity if compared to focused laser based nano-magnetometry. An analysis of the physical limits of our detection scheme enables us to estimate that measurements for structures with single digit nm widths and magnetic moments of 10{sup -16} Am{sup 2} are feasible.

  12. Optical studies of MBE-grown InN nanocolumns: Evidence of surface electron accumulation

    NASA Astrophysics Data System (ADS)

    Segura-Ruiz, J.; Garro, N.; Cantarero, A.; Denker, C.; Malindretos, J.; Rizzi, A.

    2009-03-01

    Vertically self-aligned InN nanocolumns have been investigated by means of scanning electron microscopy, Raman scattering, and photoluminescence spectroscopy. Different nanocolumn morphologies corresponding to different molecular beam epitaxy growth conditions have been studied. Raman spectra revealed strain-free nanocolumns with high crystalline quality for the full set of samples studied. Longitudinal optical modes both uncoupled and coupled to an electron plasma coexist in the Raman spectra pointing to the existence of two distinctive regions in the nanocolumn: a surface layer of degenerated electrons and a nondegenerated inner core. The characteristics of the low-temperature photoluminescence and its dependence on temperature and excitation power can be explained by a model considering localized holes recombining with degenerated electrons close to the nonpolar surface. The differences observed in the optical response of different samples showing similar crystalline quality have been attributed to the variation in the electron accumulation layer with the growth conditions.

  13. Upregulation of cell proliferation via Shc and ERK1/2 MAPK signaling in SaOS-2 osteoblasts grown on magnesium alloy surface coating with tricalcium phosphate.

    PubMed

    Jiang, Tianlong; Guo, Lei; Ni, Shenghui; Zhao, Yuyan

    2015-04-01

    Magnesium (Mg) alloys have been demonstrated to be viable orthopedic implants because of mechanical and biocompatible properties similar to natural bone. In order to improve its osteogenic properties, a porous β-tricalcium phosphate (β-TCP) was coated on the Mg-3AI-1Zn alloy by alkali-heat treatment technique. The human bone-derived cells (SaOS-2) were cultured on (β-TCP)-Mg-3AI-1Zn in vitro, and the osteoblast response, the morphology and the elements on this alloy surface were investigated. Also, the regulation of key intracellular signalling proteins was investigated in the SaOS-2 cells cultured on alloy surface. The results from scanning electron microscope and immunofluorescence staining demonstrated that (β-TCP)-Mg-3AI-1Zn induced significant osteogenesis. SaOS-2 cell proliferation was improved by β-TCP coating. Moreover, the (β-TCP)-Mg-3AI-1Zn surface induced activation of key intracellular signalling proteins in SaOS-2 cells. We observed an enhanced activation of Src homology and collagen (Shc), a common point of integration between bone morphogenetic protein 2, and the Ras/mitogen-activated protein kinase (MAPK) pathway. ERK1/2 MAP kinase activation was also upregulated, suggesting a role in mediating osteoblastic cell interactions with biomaterials. The signalling pathway involving c-fos (member of the activated protein-1) was also shown to be upregulated in osteoblasts cultured on the (β-TCP)-Mg-3AI-1Zn. These results suggest that β-TCP coating may contribute to successful osteoblast function on Mg alloy surface. (β-TCP)-Mg-3AI-1Zn may upregulate cell proliferation via Shc and ERK1/2 MAPK signaling in SaOS-2 osteoblasts grown on Mg alloy surface.

  14. Structural and optical properties of silicon nanocrystals grown by plasma-enhanced chemical vapor deposition.

    PubMed

    Prakash, G V; Daldosso, N; Degoli, E; Iacona, F; Cazzanelli, M; Gaburro, Z; Pucker, G; Dalba, P; Rocca, F; Ceretta Moreira, E; Franzò, G; Pacifici, D; Priolo, F; Arcangeli, C; Filonov, A B; Ossicini, S; Pavesi, L

    2001-06-01

    Silicon nanocrystals (Si-nc) embedded in SiO2 matrix have been prepared by high temperature thermal annealing (1000-1250 degrees C) of substoichiometric SiOx films deposited by plasma-enhanced chemical vapor deposition (PECVD). Different techniques have been used to examine the optical and structural properties of Si-nc. Transmission electron microscopy analysis shows the formation of nanocrystals whose sizes are dependent on annealing conditions and deposition parameters. The spectral positions of room temperature photoluminescence are systematically blue shifted with reduction in the size of Si-nc obtained by decreasing the annealing temperature or the Si content during the PECVD deposition. A similar trend has been found in optical absorption measurements. X-ray absorption fine structure measurements indicate the presence of an intermediate region between the Si-nc and the SiO2 matrix that participates in the light emission process. Theoretical observations reported here support these findings. All these efforts allow us to study the link between dimensionality, optical properties, and the local environment of Si-nc and the surrounding SiO2 matrix.

  15. The Electric, Magnetic, and Optical Characterization of Permalloy Oxide Grown by Dual-Ion Beam Sputtering

    NASA Astrophysics Data System (ADS)

    Compton, Maclyn; Leblanc, Elizabeth; Geerts, Wilhelmus; Simpson, Nelson; Robinson, Michael

    2014-03-01

    Permalloy (Ni80Fe20) is a commonly used soft magnetic material in magnetic reading heads. Its magnetic properties do not depend on stress, a parameter difficult to control in thin film devices. Permalloy Oxide (PyO) on the other hand, has a high resistivity (>4 .103 Ω cm), is anti-ferromagnetic and has recently been shown to strongly enhance the performance of lateral spin valve devices. Historically, the oxidation of permalloy has been seen as a defect that should be avoided by appropriate encapsulation and very little is known on its electric and optical properties. We deposited thin PyO films by Dual Ion Beam Sputtering (DIBS) at room temperature on various substrates. Van der Pauw and Hall measurements were carried out from 77K to 400K and at magnetic fields up to 9T in order to determine its electronic bandgap, resistivity, free carrier concentration, and its mobility. The dielectric properties and defects were studied using a CV-setup and an impedance analyzer. Magnetic measurements were conducted on a Quantum Design PPMS VSM to determine the state of oxidation. Optical properties were measured by a M2000 Woollam variable angle spectroscopic ellipsometer. These properties were used to determine film thickness, bandgap and the optical constants of PyO. The authors would like to thank Research Corporation for financial support.

  16. Templated growth of PFO-DBT nanorod bundles by spin coating: effect of spin coating rate on the morphological, structural, and optical properties.

    PubMed

    Fakir, Muhamad Saipul; Supangat, Azzuliani; Sulaiman, Khaulah

    2014-01-01

    In this study, the spin coating of template-assisted method is used to synthesize poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) nanorod bundles. The morphological, structural, and optical properties of PFO-DBT nanorod bundles are enhanced by varying the spin coating rate (100, 500, and 1,000 rpm) of the common spin coater. The denser morphological distributions of PFO-DBT nanorod bundles are favorably yielded at the low spin coating rate of 100 rpm, while at high spin coating rate, it is shown otherwise. The auspicious morphologies of highly dense PFO-DBT nanorod bundles are supported by the augmented absorption and photoluminescence.

  17. Fabricate Optical Microfiber by Using Flame Brushing Technique and Coated with Polymer Polyaniline for Sensing Application

    NASA Astrophysics Data System (ADS)

    Razak, N. A.; Hamida, B. A.; Irawati, N.; Habaebi, M. H.

    2017-06-01

    Adiabaticity is one of the essential criteria in producing good fabricated tapered fibers. Good tapered fibers can be use in sensor application such as humidity sensor, temperature sensor and refractive index sensor. In this paper, good tapering silica fiber is produced by using flame brushing technique and then, the microfiber is coated with polymer Polyaniline (PAni) to sense different type of alcohols with different concentrations. The outcome of this experiment gives excellent repeatability in the detection of alcohol sensing with a sensitivity of 0.1332 μW/% and a resolution of 3.764%. In conclusion, conducting polymer coated optical microfiber sensor for alcohol detection with low cost, effective and simple set-up was successfully achieved in this study.

  18. Intensity-modulated relative humidity sensing with polyvinyl alcohol coating and optical fiber gratings.

    PubMed

    Yang, Jingyi; Dong, Xinyong; Ni, Kai; Chan, Chi Chu; Shun, Perry Ping

    2015-04-01

    A relative humidity (RH) sensor in reflection mode is proposed and experimentally demonstrated by using a polyvinyl alcohol (PVA)-coated tilted-fiber Bragg grating (TFBG) cascaded by a reflection-band-matched chirped-fiber Bragg grating (CFBG). The sensing principle is based on the RH-dependent refractive index of the PVA coating, which modulates the transmission function of the TFBG. The CFBG is properly designed to reflect a broadband of light spectrally suited at the cladding mode resonance region of the TFBG, thus the reflected optical signal passes through and is modulated by the TFBG again. As a result, RH measurements with enhanced sensitivity of ∼1.80  μW/%RH are realized and demodulated in the range from 20% RH to 85% RH.

  19. Local field-induced optical properties of Ag-coated CdS quantum dots.

    PubMed

    Je, Koo-Chul; Ju, Honglyoul; Treguer, Mona; Cardinal, Thierry; Park, Seung-Han

    2006-08-21

    Local field-induced optical properties of Ag-coated CdS quantum dot structures are investigated. We experimentally observe a clear exciton peak due to the quantum confinement effect in uncoated CdS quantum dots, and surface plasmon resonance and red-shifted exciton peak in Ag-coated CdS composite quantum dot structures. We have calculated the Stark shift of the exciton peak as a function of the local field for different silver thicknesses and various sizes of quantum dots based on the effective-mass Hamiltonian using the numerical-matrix-diagonalization method. Our theoretical calculations strongly indicate that the exciton peak is red-shifted in the metal-semiconductor composite quantum dots due to a strong local field, i.e., the quantum confined Stark effect.

  20. Sensitive and absolute absorption measurements in optical materials and coatings by laser-induced deflection technique

    NASA Astrophysics Data System (ADS)

    Mühlig, Christian; Bublitz, Simon

    2012-12-01

    The laser-induced deflection (LID) technique, a photo-thermal deflection setup with transversal pump-probe-beam arrangement, is applied for sensitive and absolute absorption measurements of optical materials and coatings. Different LID concepts for bulk and transparent coating absorption measurements, respectively, are explained, focusing on providing accurate absorption data with only one measurement and one sample. Furthermore, a new sandwich concept is introduced that allows transferring the LID technique to very small sample geometries and to significantly increase the sensitivity for materials with weak photo-thermal responses. For each of the different concepts, a representative application example is given. Particular emphasis is placed on the importance of the calibration procedure for providing absolute absorption data. The validity of an electrical calibration procedure for the LID setup is proven using specially engineered surface absorbing samples. The electrical calibration procedure is then applied to evaluate two other approaches that use either doped samples or highly absorptive reference samples.

  1. Comparative investigation of hydrogen bonding in silicon based PECVD grown dielectrics for optical waveguides

    NASA Astrophysics Data System (ADS)

    Ay, F.; Aydinli, A.

    2004-06-01

    Silicon oxide, silicon nitride and silicon oxynitride layers were grown by a PECVD technique. The resulting refractive indices of the layers varied between 1.47 and 1.93. The compositional properties of the layers were analyzed by FTIR and ATR infrared spectroscopy techniques. Comparative investigation of bonding structures for the three different layers was performed. Special attention was given to analyze N-H bond stretching absorption at 3300-3400 cm -1. Quantitative results for hydrogen related bonding concentrations are presented based on IR analysis. An annealing study was performed in order to reduce or eliminate this bonding types. For the annealed samples the N-H bond concentration was strongly reduced as verified by FTIR transmittance and ATR spectroscopic methods. A correlation between the N-H concentration and absorption loss was verified for silicon oxynitride slab waveguides. Moreover, a single mode waveguide with silicon oxynitride core layer was fabricated. Its absorption and insertion loss values were determined by butt-coupling method, resulting in low loss waveguides.

  2. Impact of extended defects on optical properties of (1-101)GaN grown on patterned Si

    NASA Astrophysics Data System (ADS)

    Okur, S.; Izyumskaya, N.; Zhang, F.; Avrutin, V.; Metzner, S.; Karbaum, C.; Bertram, F.; Christen, J.; Morkoç, H.; Özgür, Ü.

    2014-03-01

    The optical quality of semipolar (1 101)GaN layers was explored by time- and polarization-resolved photoluminescence spectroscopy. High intensity bandedge emission was observed in +c-wing regions of the stripes as a result of better structural quality, while -c-wing regions were found to be of poorer optical quality due to basal plane and prismatic stacking faults (BSFs and PSFs) in addition to a high density of TDs. The high optical quality region formed on the +cwings was evidenced also from the much slower biexponential PL decays (0.22 ns and 1.70 ns) and an order of magnitude smaller amplitude ratio of the fast decay (nonradiative origin) to the slow decay component (radiative origin) compared to the -c-wing regions. In regard to defect-related emission, decay times for the BSF and PSF emission lines at 25 K (~ 0.80 ns and ~ 3.5 ns, respectively) were independent of the excitation density within the range employed (5 - 420 W/cm2), and much longer than that for the donor bound excitons (0.13 ns at 5 W/cm2 and 0.22 ns at 420 W/cm2). It was also found that the emission from BSFs had lower polarization degree (0.22) than that from donor bound excitons (0.35). The diminution of the polarization degree when photogenerated carriers recombine within the BSFs is another indication of the negative effects of stacking faults on the optical quality of the semipolar (1101)GaN. In addition, spatial distribution of defects in semipolar (1101)-oriented InGaN active region layers grown on stripe patterned Si substrates was investigated using near-field scanning optical microscopy. The optical quality of -c- wing regions was found to be worse compared to +c-wing regions due to the presence of higher density of stacking faults and threading dislocations. The emission from the +c-wings was very bright and relatively uniform across the sample, which is indicative of a homogeneous In distribution.

  3. Ultrafast all-optical switching based on indium gallium arsenic phosphide grown by helium plasma-assisted molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Qian, Li

    We present the first experimental study of the optical properties of HELP InGaAsP (InGaAsP grown by He-plasma- assisted molecular beam epitaxy) relevant to all-optical switching, and the first demonstration of picosecond switching using this material. We observed an optical response time of 15 ps, a nonlinear index change as large as 0.077, a sharp absorption band edge, and a small absorption tail in HELP InGaAsP. The unique coexistence of ultrafast response, large interband nonlinearity, and small band-tail absorption, never before reported, makes HELP InGaAsP particularly suitable for ultrafast all-optical switching. Additionally, faster response (subpicosecond) was achieved by doping the material with beryllium, and moderate doping (up to ~1018 cm-3) did not significantly alter the absorption edge. We systematically studied the response time variations with doping concentration, annealing temperature, carrier density, and wavelength. We conclude that, (a)Be doping reduces the response time by compensating for donor-like mid-gap states, thus increasing the electron trap concentration; (b)annealing removes defects responsible for fast carrier trapping; (c)the response time increases with carrier density due to limited trap states; (d)the response time varies with wavelength due to difference in electron and hole trapping cross-sections, which were determined based on experimental results and a phenomenological two-trap- level rate equation model. We investigated two types of HELP-InGaAsP-based all- optical switching devices, the nonlinear directional coupler (NLDC) and the asymmetric Fabry-Pérot (AFP) switch. Based on numerical modelling and waveguide loss measurements, we conclude that, while HELP-InGaAsP-based passive NLDCs are in principle viable, practical devices will tend to require high switching energy, and will likely experience low contrast and high insertion loss. We demonstrated that AFP devices will outperform NLDCs in contrast ratio, throughput

  4. OMEGA: A NEW COLD X-RAY SIMULATION FACILITY FOR THE EVALUATION OF OPTICAL COATINGS

    SciTech Connect

    Fisher, J H; Newlander, C D; Fournier, K B; Beutler, D E; Coverdale, C A; May, M J; Tobin, M; Davis, J F; Shiekh, D

    2007-04-27

    We report on recent progress for the development of a new cold X-ray optical test capability using the Omega Facility located at the Laboratory for Laser Energetics (LLE) at the University of Rochester. These tests were done on the 30 kJ OMEGA laser at the Laboratory for Laser Energetics (LLE) at the University of Rochester, Rochester, NY. We conducted a six-shot series called OMEGA II on 14 July 2006 in one eight-hour day (supported by the Defense Threat Reduction Agency). The initial testing was performed using simple protected gold optical coatings on fused silica substrates. PUFFTFT analyses were completed and the specimen's thermal lateral stress and transverse stress conditions were calculated and interpreted. No major anomalies were detected. Comparison of the pre- and posttest reflective measurements coupled with the TFCALC analyses proved invaluable in guiding the analyses and interpreting the observed damage. The Omega facility is a high quality facility for performing evaluation of optical coatings and coupons and provides experience for the development of future National Ignition Facility (NIF) testing.

  5. Femtosecond laser direct-write of optofluidics in polymer-coated optical fiber

    NASA Astrophysics Data System (ADS)

    Joseph, Kevin A. J.; Haque, Moez; Ho, Stephen; Aitchison, J. Stewart; Herman, Peter R.

    2017-03-01

    Multifunctional lab in fiber technology seeks to translate the accomplishments of optofluidic, lab on chip devices into silica fibers. a robust, flexible, and ubiquitous optical communication platform that can underpin the `Internet of Things' with distributed sensors, or enable lab on chip functions deep inside our bodies. Femtosecond lasers have driven significant advances in three-dimensional processing, enabling optical circuits, microfluidics, and micro-mechanical structures to be formed around the core of the fiber. However, such processing typically requires the stripping and recoating of the polymer buffer or jacket, increasing processing time and mechanically weakening the device. This paper reports on a comprehensive assessment of laser damage in urethane-acrylate-coated fiber. The results show a sufficient processing window is available for femtosecond laser processing of the fiber without damaging the polymer jacket. The fiber core, cladding, and buffer could be simultaneously processed without removal of the buffer jacket. Three-dimensional lab in fiber devices were successfully fabricated by distortion-free immersionlens focusing, presenting fiber-cladding optical circuits and progress towards chemically-etched channels, microfluidic cavities, and MEMS structure inside buffer-coated fiber.

  6. Coated photodiode technique for the determination of the optical constants of reactive elements: La and Tb

    NASA Astrophysics Data System (ADS)

    Seely, John F.; Uspenskii, Yurii A.; Kjornrattanawanich, Benjawan; Windt, David L.

    2006-08-01

    A novel technique, utilizing thin films with protective capping layers deposited onto silicon photodiode substrates, has been developed to accurately determine the optical constants of reactive elements such as the rare earths and transition metals. Depositing protected layers on photodiode substrates has three primary advantages over the study of the transmittance of free-standing films and the angle-dependent reflectance of coatings on mirror substrates. First, it is easy to deposit a thin protective capping layer that prevents oxidation or contamination of the underlying reactive layer. Second, very thin layers of materials that have intrinsically low transmittance can be studied. Third, the optical constants are determined from the bulk properties of the protected layer and are not influenced by reflectance from the top surface that can be affected by oxidation or contamination. These and other benefits of this technique will be discussed, and results for La and Tb will be presented. The determined optical constants are significantly different from the CXRO and other tabulated values. The rare earth (lanthanide) elements with atomic numbers 57-71 have 5d or 4f open shells, and this open shell structure results in transmission windows in the extreme ultraviolet wavelength range >45 nm where materials typically have low transmittance. These transmission windows make possible the fabrication of a new class of multilayer interference coatings, based on rare earth elements, with relatively high peak reflectances and narrow reflectance profiles, both important factors for the imaging of solar and laboratory radiation sources with multilayer telescopes.

  7. Active control of the optical properties of nanoscale coatings using 'smart' nanoparticles

    NASA Astrophysics Data System (ADS)

    Cortie, Michael B.; Barnett, Michael; Ford, Michael J.

    2007-09-01

    Coatings that can self-modulate their optical properties as a function of an external stimulus are of significant technological interest. In this regard, the possibilities for thermo- or electrochromic materials such as VO II and WO 3 are already comparatively well-known. Here, however, we explore a new kind of 'smart' coating, based on the active control of a plasmon resonance in nanoparticles. One possible system is based on the modulation of the plasmon resonance of a precious metal nanorod or nanosphere by an active dielectric shell. The active dielectric undergoes an insulator-to-metal transition on increase of temperature which modulates the plasmon resonance of the underlying precious metal nanoparticle, thereby changing the wavelength at which its optical extinction is maximum. In the case of nanorods, the absorption maximum of the longitudinal plasmon is particularly sensitive to the aspect ratio of the nanoparticle and the dielectric properties of the environment, and may be readily tuned across the visible and near-infrared portions of the spectrum. In addition, nanoparticles of certain thermochromic dielectrics, such as VO II, are expected to have a plasmon resonance of their own which can be switched on or off by control of the temperature. We consider some of the possibilities, using both the discrete dipole approximation and the exact analytical solution due to Mie to calculate the optical properties.

  8. Optical measurements of dynamic adhesive forces between bacteria and protein-coated surfaces

    NASA Astrophysics Data System (ADS)

    Simpson, Kathryn H.; Bowden, Gabriela; Hook, Magnus; Anvari, Bahman

    2003-06-01

    Bacterial adhesion to host tissue is an initial step in the infectious process. Staphylococcus aureus, a major human pathogen, has covalently anchored cell surface adhesins called microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) which mediate specific adhesion to extracellular matrix (ECM) molecules. Understanding MSCRAMM binding is potentially useful in developing effective antibacterial drugs. In this study, optical tweezers were used in conjunction with a quadrant photodetector to measure adhesive forces between MSCRAMMs and surfaces coated with the ECM molecule fibronectin. Using a piezoelectrically driven stage, a fibronectin-coated microsphere adherent to a coverslip was brought into contact with a cell optically trapped at 830 nm. The microsphere was subsequently moved away from the cell, and a quadrant photodiode monitored the cell displacement from the trap center during the detachment process. The photodetector voltage signals were subsequently converted into the adhesive forces between MSCRAMMs and fibronectin based on a calibration using Stoke"s law for viscous drag. Optical detection of the trapped bead displacement allowed us to study both the dynamics of the detachment process and observe the effects of various loading rates. This technique can be extended to identify the contributions of various MSCRAMM domains to adhesion in order to develop new methods of treating infections.

  9. Optical properties of hydrogenated amorphous carbon films grown from methane plasma

    NASA Technical Reports Server (NTRS)

    Pouch, J. J.; Alterovitz, S. A.; Warner, J. D.; Liu, D. C.; Lanford, W. A.

    1985-01-01

    A 30 kHz ac glow discharge formed from methane gas was used to grow carbon films on InP substrates. Both the growth rate, and the realitive Ar ion sputtering rate at 3 keV varied monotonically with deposition power. Results from the N-15 nuclear reaction profile experiments indicated a slight drop in the hydrogen concentration as more energy was dissipated in the ac discharge. Values for the index of refraction and extinction coefficient ranged from 1.721 to 1.910 and 0 to -0.188, respectively. Optical bandgaps as high as 2.34 eV were determined.

  10. Stoichiometric YFe2O4-δ single crystals grown by the optical floating zone method

    NASA Astrophysics Data System (ADS)

    Mueller, Thomas; Groot, Joost de; Strempfer, Jörg; Angst, Manuel

    2015-10-01

    We report the growth, by the optical floating zone method of YFe2O4-δ single crystals, showing for the first time the same magnetization as highly stoichiometric (δ = 0.00) powder samples and sharp superstructure reflections in single crystal X-ray diffraction. The latter can be attributed to three dimensional long-range charge ordering. Resonant X-ray diffraction at the Fe K-edge with full linear polarization analysis was used for the investigation of the possibility of orbital order.

  11. Structural and optical characteristics of the hexagonal ZnO films grown on cubic MgO (001) substrates.

    PubMed

    Shen, Xiangqian; Zhou, Hua; Li, Yaping; Kang, Junyong; Zheng, Jin-Cheng; Ke, Shanming; Wang, Qingkang; Wang, Hui-Qiong

    2016-11-01

    In this Letter, we report on the structural and optical characteristics of ZnO films with a wurtzite structure grown on MgO (001) substrates with cubic structures. The ZnO films were prepared through the molecular beam epitaxy method, and growth orientation transformation from [0001] to [10-10] direction was observed with the change of growth temperature and thickness. The x-ray diffraction pole figures and in situ RHEED patterns demonstrated that the rotational relationship among grains within the ZnO films appeared in a typical two-fold rotation of about 30° for the [0001] growth orientation and four-fold rotation of about 30° or 60° for the [10-10] growth orientation, respectively. Last, we investigated their optical properties through measuring the transmission and photoluminescence spectra of the ZnO films, which showed the bulk-like bandgap feature of the ZnO films in spite of the existing growth orientation transformation.

  12. Influence of low-energy plasma annealing on structural and optical properties of silver nanoclusters grown by magnetron sputtering deposition

    NASA Astrophysics Data System (ADS)

    Antad, V.; Simonot, L.; Babonneau, D.

    2014-03-01

    Structural and optical modifications induced by low-energy (≤80 eV) bias-plasma annealing of silver nanoclusters (2-25 nm) grown by magnetron sputtering deposition are reported. By combining postmortem structural characterizations and real-time optical measurements, we show that etching effects associated with enhanced Ag mobility result in progressive and irreversible changes of both the morphology and organization of the nanoclusters (i.e., decrease of the cluster size and intercluster distance as well as increase of their out-of-plane aspect ratio). Surface plasmon resonance bands of the nanoclusters are also modified by plasma treatment, which causes a blue-shift together with an amplitude decrease and a narrowing of the band. In addition, the kinetics of plasma-induced modifications can be easily controlled by varying the applied bias voltage. Therefore, plasma annealing could emerge as an efficient alternative to more traditional thermal annealing treatments for tuning the plasmonic properties of noble metal nanoclusters with great flexibility.

  13. Substrate dependent structural, optical and electrical properties of ZnS thin films grown by RF sputtering

    NASA Astrophysics Data System (ADS)

    Pathak, Trilok K.; Kumar, Vinod; Purohit, L. P.; Swart, H. C.; Kroon, R. E.

    2016-10-01

    Zinc sulphide (ZnS) films are of great importance for applications in various optoelectronic devices. ZnS thin films were grown on glass, indium tin oxide (ITO) and Corning glass substrates by radio-frequency magnetron sputtering at a temperature of 373 K and a comparative study of the structural, optical and electrical properties was performed using X-ray diffraction (XRD), scanning electron microscopy, optical and current-voltage (I-V) measurements. The XRD patterns showed that the sputtered thin films exhibited good crystallinity with the (111) peak around 2θ=28.3° indicating preferential orientation of the cubic structure. The maximum strain and most densely packed grains were obtained for the Corning glass substrate. The transmittance spectra of the films were measured in the wavelength range from 200 to 800 nm, showing that the films are about 77% transparent in the visible region. A slight change of 3.50 eV to 3.54 eV was found for the bandgap of the films deposited on different substrates. The ZnS thin films deposited on Corning glass show better crystallinity, morphology and I-V characteristics than that deposited on ordinary glass and ITO substrates.

  14. Synthesis and optical characteristics of yttrium-doped zinc oxide nanorod arrays grown by hydrothermal method.

    PubMed

    Park, Hyunggil; Kim, Younggyu; Ji, Iksoo; Lee, Sang-Heon; Kim, Jin Soo; Kim, Jin Soo; Leem, Jae-Young

    2014-11-01

    Yttrium-doped ZnO (YZO) nanorods were synthesized by hydrothermal growth on a quartz substrate with various post-annealing temperatures. To investigate the effects of post-annealing on the optical properties and parameters of the nanorods, X-ray diffractometry (XRD), photoluminescence (PL) measurement, and ultraviolet (UV)-visible spectroscopy were used. From the XRD investigation, the full width at half maximum (FWHM) and the dislocation density of the nanorods was found to increase with an increase in the post-annealing temperature. In the PL spectra, the intensity of the near band edge (NBE) emission peak in the UV region also increases with an increase in the temperature of post-annealing. The deep level emission (DLE) peak in the visible region changes with various post-annealing temperatures, and its intensity increases remarkably with post-annealing at 800 degrees C. In this paper, changes in the optical parameters of the nanorods caused by variation in the behavior of Y during post-annealing was investigated, with properties such as absorption coefficients, refractive indices, and dispersion parameters being obtained from transmittance and reflectance analysis.

  15. Optical properties of LFZ grown β-Ga2O3:Eu3+ fibres

    NASA Astrophysics Data System (ADS)

    Santos, N. F.; Rodrigues, J.; Fernandes, A. J. S.; Alves, L. C.; Alves, E.; Costa, F. M.; Monteiro, T.

    2012-09-01

    Due to their relevance for electronic and optoelectronic applications, transparent conductive oxides (TCO) have been extensively studied in the last decades. Among them, monoclinic β-Ga2O3 is well known by its large direct bandgap of ˜4.9 eV being considered a deep UV TCO suitable for operation in short wavelength optoelectronic devices. The wide bandgap of β-Ga2O3 is also appropriate for the incorporation of several electronic energy levels such as those associated with the intra-4fn configuration of rare earth ions. Among these, Eu3+ ions (4f6) are widely used as a red emitting probes both in organic and inorganic compounds. In this work, undoped and Eu2O3 doped (0.1 and 3.0 mol%) Ga2O3 crystalline fibres were grown by the laser floating zone approach. All fibres were found to stabilize in the monoclinic β-Ga2O3 structure while for the heavily doped fibres the X-ray diffraction patterns show, in addition a cubic europium gallium garnet phase, Eu3Ga5O12. The spectroscopic properties of the undoped and Eu doped fibres were analysed by Raman spectroscopy, low temperature photoluminescence (PL) and photoluminescence excitation (PLE). The Eu3+ luminescence is mainly originated in the garnet, from where different europium site locations can be inferred. The spectral analysis indicates that at least one of the centres corresponds to Eu3+ ions in dodecahedral site symmetry. For the lightly doped samples, the spectral shape and intensity ratio of the 5D0 → 7FJ transitions is totally different from those on Eu3Ga5O12, suggesting that the emitting ions are placed in low symmetry sites in the β-Ga2O3 host.

  16. Scalable process for mitigation of laser-damaged potassium dihydrogen phosphate crystal optic surfaces with removal of damaged antireflective coating.

    PubMed

    Elhadj, S; Steele, W A; VanBlarcom, D S; Hawley, R A; Schaffers, K I; Geraghty, P

    2017-03-10

    We investigate an approach for the recycling of laser-damaged large-aperture deuterated potassium dihydrogen phosphate (DKDP) crystals used for optical switching (KDP) and for frequency conversion (DKDP) in megajoule-class high-power laser systems. The approach consists of micromachining the surface laser damage sites (mitigation), combined with multiple soaks and ultrasonication steps in a coating solvent to remove, synergistically, both the highly adherent machining debris and the laser-damage-affected antireflection coating. We identify features of the laser-damage-affected coating, such as the "solvent-persistent" coating and the "burned-in" coating, that are difficult to remove by conventional approaches without damaging the surface. We also provide a solution to the erosion problem identified in this work when colloidal coatings are processed during ultrasonication. Finally, we provide a proof of principle of the approach by testing the full process that includes laser damage mitigation of DKDP test parts, coat stripping, reapplication of a new antireflective coat, and a laser damage test demonstrating performance up to at least 12  J/cm2 at UV wavelengths, which is well above current requirements. This approach ultimately provides a potential path to a scalable recycling loop for the management of optics in large, high-power laser systems that can reduce cost and extend lifetime of highly valuable and difficult to grow large DKDP crystals.

  17. Scalable process for mitigation of laser-damaged potassium dihydrogen phosphate crystal optic surfaces with removal of damaged antireflective coating

    DOE PAGES

    Elhadj, S.; Steele, W. A.; VanBlarcom, D. S.; ...

    2017-03-07

    Here, we investigate an approach for the recycling of laser-damaged large-aperture deuterated potassium dihydrogen phosphate (DKDP) crystals used for optical switching (KDP) and for frequency conversion (DKDP) in megajoule-class high-power laser systems. The approach consists of micromachining the surface laser damage sites (mitigation), combined with multiple soaks and ultrasonication steps in a coating solvent to remove, synergistically, both the highly adherent machining debris and the laser-damage-affected antireflection coating. We then identify features of the laser-damage-affected coating, such as the “solvent-persistent” coating and the “burned-in” coating, that are difficult to remove by conventional approaches without damaging the surface. We also providemore » a solution to the erosion problem identified in this work when colloidal coatings are processed during ultrasonication. Finally, we provide a proof of principle of the approach by testing the full process that includes laser damage mitigation of DKDP test parts, coat stripping, reapplication of a new antireflective coat, and a laser damage test demonstrating performance up to at least 12 J/cm2 at UV wavelengths, which is well above current requirements. Our approach ultimately provides a potential path to a scalable recycling loop for the management of optics in large, high-power laser systems that can reduce cost and extend lifetime of highly valuable and difficult to grow large DKDP crystals.« less

  18. Optical gain characteristics of a-plane GaN/AlGaN quantum well lasers grown on strain-engineered MgZnO layer

    NASA Astrophysics Data System (ADS)

    Park, Seoung-Hwan

    2017-09-01

    Optical gain characteristics of a-plane (11 2 bar 0) AlGaN/GaN quantum well (QW) lasers grown on a GaN buffer with strain anisotropy using a strain-engineered MgZnO layer were investigated using the multiband effective mass theory. The calculated transition energies for QW structures grown on MgZnO layer are in good agreement with experimental results. The optical gain of the QW structure grown on the MgZnO substrate is dominated by the z ‧ -polarization because the dominant states constituting the topmost valence subband for the QW structure changes from | Y ‧ > - to | Z ‧ > -like and carriers occupy higher states above k∥ = 0 at a higher carrier density. On the other hand, the optical gain of the QW structure grown on conventional GaN buffer is dominated by both y ‧ - and z ‧ -polarizations. Thus, the optical polarization characteristics of a-plane AlGaN/GaN QW lasers can be engineered by using MgZnO substrate.

  19. Impact of non-integer planetary revolutions on the distribution of evaporated optical coatings

    DOE PAGES

    Oliver, J. B.

    2017-02-08

    Planetary substrate rotation for optical-coating deposition is evaluated based on initial and final positions for a given layer with different numbers of revolutions and various deposition-source locations. The influence of partial revolutions of the rotation system is analyzed relative to the total number of planetary revolutions in that layer to determine the relative impact on film thickness and uniformity. Furthermore, guidance is provided on the necessary planetary revolutions that should take place in each layer versus the expected error level in the layer thickness for the modeled system.

  20. VUV and XUV reflectance of optically coated mirrors for selection of high harmonics

    SciTech Connect

    Larsen, K. A.; Cryan, J. P.; Shivaram, N.; Champenois, E. G.; Wright, T. W.; Ray, D.; Kostko, O.; Ahmed, M.; Belkacem, A.; Slaughter, D. S.

    2016-08-08

    We report the reflectance, ~1° from normal incidence, of six different mirrors as a function of photon energy, using monochromatic vacuum ultraviolet (VUV) and extreme ultraviolet (XUV) radiation with energies between 7.5 eV and 24.5 eV. The mirrors examined included both single and multilayer optical coatings, as well as an uncoated substrate. Furthermore, we discuss the performance of each mirror, paying particular attention to the potential application of suppression and selection of high-order harmonics of a Ti:sapphire laser.