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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

WAVEFRONT ERRORS PRODUCED BY MULTILAYER THIN-FILM OPTICAL COATINGS

Knowlden, Robert Edward January 1981 (has links)
The mirrors used in high energy laser systems have at least two requirements that are uncommon in optical engineering: the reflectance of such mirrors must be very high (> 0.999), and the level of aberrations introduced by the mirrors is desired to be very low, typically λ/50 peak at 3.8 μ. The first requirement can be met by using multilayer thin film coatings, but such coatings can themselves produce aberrations in an optical system. One possible effect in multilayers is that such coatings produce an optical phase change on reflection that varies with angle of incidence and polarization of the illuminating beam. On a strongly curved mirror, such as an f/1.5 parabola used as a collimator, these effects may be appreciable for some coatings (e.g., λ/13 for a broadband all-dielectric reflector), but for an enhanced silver coating the effects are small, typically λ/400 of error that is almost entirely in the form of a small focus shift. If this same parabola is tested at its center of curvature, the coating-caused aberration due to angle of incidence effects are nearly zero (e.g., λ/50,000 for the broadband reflector that gave λ/13 when the parabola was used as a collimator). The wavefront errors due to coating nonuniformities are usually more important than angle of incidence effects. The simplest type of coating nonuniformity to analyze is a proportional error, i.e., an error where the ratios of the thicknesses of the layers are fixed but the thin film stack varies in total thickness across a surface. For a six-layer enhanced reflector for use at 3.8 μ, a 1% thickness error produces an approximate λ/100 wavefront error. At visible wavelengths, however, the aberration produced by such a coating error can be very different because of the optical interference nature of the coating. Means may be developed to estimate the performance of such an infrared reflector from measurements at visible wavelengths. If the errors produced by the coating are to be distinguished from those existing in the test due to misalignment or gravitational flexure of a large mirror, two or more wavelengths must be chosen. There are ambiguities in such a test that may be resolved by choice of an appropriate coating design or by using enough wavelengths in the visible, and both means have been studied. A technique was found where the infrared wavefront can be determined for a coating with proportional thickness errors if the coating prescription is known: interferograms of the mirror are made at three visible wavelengths, and the IR wavefront error due to the coating error is determined in a way that is insensitive to any errors caused by distortion of the substrate or even fairly large misalignments in the optical test of a mirror's figure.
52

The structure of multilayer films studies by sum frequency generation spectroscopy

Kett, Peter John Nicholas January 2011 (has links)
No description available.
53

Equilibrium and dynamical properties of epitaxial ferroelectric heterostructures

Kim, Yeongkwan 05 1900 (has links)
No description available.
54

Langmuir films and nanoparticle applications of a spider silk protein analog

Davidson, Patricia Marie L. January 2006 (has links)
A synthetic analog of a spider silk protein (M4) was studied. Langmuir films were made and an inflexion in the isotherm indicated conformational changes upon compression. Deposition onto solid substrates was most successful using a hydrophobic substrate and the Langmuir-Schaeffer method. AFM was used to image the surface, which was mesh like and did not show any indication of order. / Gold nanoparticles were produced in the presence of the protein and protein solutions were added to read made nanoparticles for the purpose of displacing the weak ligands present. CD measurements were performed on the protein solutions to study its conformation. Nanoparticle size information was obtained from TEM images. DLS was used to determine if the protein was affected by the addition of the gold nanoparticles. Precipitation of the protein was shown not to affect the nanoparticles.
55

Designed superlattices : from lattice matched to lattice mismatched building blocks /

Nguyen, Ngoc Thanh, January 2007 (has links)
Thesis (Ph. D.)--University of Oregon, 2007. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 209-231). Also available for download via the World Wide Web; free to University of Oregon users.
56

Synthesis and characterization of novel nanoparticles

Peña, David Jude. January 2001 (has links) (PDF)
Thesis (Ph.D.)--Pennsylvania State University, 2001. / Includes bibliographical references.
57

Fabrication and characterization of superconducting PLD MgB2 thin films

Zhao, Yue. January 2005 (has links)
Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references.
58

Nanoscale investigation of polarization interaction and polarization switching in ferroelectric P(VDF-TrFE) copolymer samples

Kim, Jihee. January 1900 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed July 22, 2008). PDF text: ix, 169 p. : ill. (some col.) ; 8 Mb. UMI publication number: AAT 3299685. Includes bibliographical references. Also available in microfilm and microfiche formats.
59

Synthesis and characterization of [(NbSe₂)m̲(CrSe₂)n̳] superlattices /

Berseth, Polly A., January 2004 (has links)
Thesis (Ph. D.)--University of Oregon, 2004. / On t.p. "m̲" and "n̲" are subscript. Typescript. Includes vita and abstract. Includes bibliographical references (leaves 147-153). Also available for download via the World Wide Web; free to University of Oregon users.
60

Synthesis of ternary Chevrel phases using elemental modulated reactants /

Schneidmiller, Robert, January 1999 (has links)
Thesis (Ph. D.)--University of Oregon, 1999. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 100-105). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9947982.

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