Margaritondo. Optical Reflectance Measurements for Commonly Used Reflectors Optical properties of aggregated gold on aluminum. The frequency-dependent The effects of prolonged heating at 350 degrees. We find that for the These effects are believed to arise from changes in the localized state density and distribution in the forbidden gap owing to the introduction of defects into the random network by the irradiation. In a second more versatile construction aluminum is coated with two dielectric layers separated by a semi-transparent metal film. Aggregation of the gold and diffusion of the aluminum into the gold by heat treatment produces surfaces with high absorptance in the visible and high reflectance in the infrared, characteristics required of selective solar absorbers. Journal of the Optical Society of America. conductivity obtained from Kramers-Kronig analysis of the metallic All rights reserved. σ>2×104 Ω-1 cm-1. Dielectric resonance, local field distribution, and optical response in 3D resonant composites, Optical and electrical conductivity of polyaniline. The volume fraction, f, of metal in the samples studied was between f = 0.03 and f - 1. The absorption data are consistent with a direct For the disordered composites in 2D and 3D, inverse participation ratios (IPR) with q = 2 are used to represent the localization of the field. Due to the different values of Greens function in 2D and 3D, for the same cluster, the values of the dielectric resonances in 3D are smaller than those in 2D, but the fields are more localized than those in 2D. Application of effective-medium theory implies an intrinsic dc Finally, both for 2D and 3D disordered composites, the absorption range broadens with increasing impurity concentration, and a red shift of the absorption peak is observed in 3D. PDF | The reflectance in the infrared and visible ... and effective linear optical responses for one-bond, two-bond and three-bond clusters, as well as for various disordered composites. The measured dc values have thus far been limited by the low-density visible exhausts the oscillator strength sum rule for π electrons Kramers-Kronig analysis of the reflection data has been carried out to Using the formalism, we investigate the dielectric resonances, local-field distribution, and effective linear optical responses for one-bond, two-bond and three-bond clusters, as well as for various disordered composites. spectrum and also to increase their photoconductivity. In situ measurements showed that the effect of bombardment on the films was to enhance their electrical conductivity in a manner consistent with variable range hopping, to increase their optical absorption in the near IR and visible, The optical reflectances of evaporated deposits of gold on aluminum have been measured in the visible and IR regions. In the first design aluminum is coated with evaporated films of germanium and silicon monoxide, each film approximately one-quarter wavelength thick. There is some evidence that these defects may not be homogeneously distributed throughout the material. Two multilayer film designs especially suitable for producing mirror coatings with low visible and high infrared reflectance are described. These filter mirrors are useful for decreasing unwanted visible radiation in infrared equipment. B15, 3272 (1977). (Leipz.) Electronic structure of polyacetylene: Optical and infrared studies of undoped semiconducting (CH)x... Mirror Coatings for Low Visible and High Infrared Reflectance. The sum rule of dielectric resonance in three-component composites is extended to d dimensions. © 2008-2020 ResearchGate GmbH. The reflectance in the infrared and visible (0.08 eV to 3.2 eV) has been measured for aluminum small particles compacted into potas- sium chloride. Berger L. Forro G.G. A203, 385 (1904). Comparison of experiment with simple theories shows that the self consistent theory predicts the general form of the reflectance if the low concentration for first achieving conduction is taken into consideration. In one example of this design, consisting of Al–SiO–Al–SiO, the low-reflectance region extends from 0.4µ to 1.5µ and more than 90% reflectance is obtained for all wavelengths longer than 3µ. The aluminum particles were prepared by evaporation o o in inert gas atmosphere and had mean diameters of 200A and 600A. gap of approximately 1.4 eV in the trans-(CH)x. Trans. consistent with an interband transition. When we increase the concentration of impurity bonds, a blue shift of IPR peaks occurs in 3D, while in 2D, these peaks are very stable. The band structure and electronic properties of pure and heavily doped The effect of single and multilayer coatings on the reflectance of metals is discussed. [CH(AsF5)0.15]x of conductivity for metallic investigated by a combination of optical-absorption and -reflection For f - 0.15 the specimens exhibited finite dc conductivity. the visible (4.0 eV). For the same resonance, the intensity of the local-field in 3D is also weaker than that in the 2D case, but the fields are more localized than those in 2D. Evaporated films of germanium and silicon have been irradiated at 14K in high vacuum with saturation doses of 100 keV Ge** plus and Si** plus ions respectively. Instrument An instrument for measuring the angular distribution of reflectance has been designed and built . The main feature of the data is a decreasing reflec- tance with increasing frequency. D. A. G. Bruggeman, Ann. Rev. fibril morphology. Access scientific knowledge from anywhere. METHODS A. polymer reflection data suggests "interrupted-strand" behavior. All content in this area was uploaded by David Tanner on Jan 28, 2016. Reflectance and Texture of Real-World Surfaces KRISTIN J. DANA Columbia University BRAM VAN GINNEKEN Utrecht University SHREE K. NAYAR Columbia University JAN J. KOENDERINK Utrecht University In this work, we investigate the visual appearance of real-world surfaces and the dependence of appearance on the geometry of imaging conditions. this construction the visible reflectance is decreased to 2% and a steep rise in reflectance from 5% to 90% takes place from 0.7µ to 1.2µ. polyacetylene (both as grown and stretch oriented) have been Scitation is the online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies, H.H. undoped semiconducting polymer, the strong transition observed in the Kramers-Kronig inversion of the reflectances yield frequency dependent conductivi- ties which are not like those of a simple metal. J. C. Maxwell-Garnett, Philos. We extend the Greens function formalism in a binary 2D composite to 3D. III. A Join ResearchGate to find the people and research you need to help your work. SOME EFFECTS OF ION BOMBARDMENT IN ELEMENTAL DISORDERED FILMS. 24, 636 (1935). Phys. The magnitude of the reflectance increases with metal concentration. Soc. In one example using. The changes introduced by bombardment were reversible on annealing to 300K, after an initial bombardment and anneal. measurements in the frequency range from the middle ir (0.1 eV) through Roy. J. I. Gittleman and B. Abeles, Phys. obtain σ(ω) and ɛ(ω). Optical Reflectance Measurements for Commonly Used Reflectors Martin Janecek, Member, IEEE, and William W. Moses, Fellow, IEEE T. 2 incident angle.