Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 34 for “"Optical constants"”.
-
Inversion of Light Scattering Measurements for Particle Size and Optical Constants
… to be valuable tools in determining the size and optical properties of aerosol particles. Laser light scattering techniques can be used unobtrusively in harsh environments, so the development and improvement of these techniques is of great interest. The primary difficulty associated with light …
-
Changes of some optical constants of thin metallic films due to exposure to gases
The reflectivity, transmissivity, and absorptivity of freshly evaporated silver and copper films were measured in vacuo and then in the presence of several gases. These measurements were performed, using the photoelectric method, with two photomultiplier tubes (931-A and 1P21), and were made at an …
-
The optical properties of oxide films on copper and copper alloys
… self-nulling ellipsometer. From this data the optical constants and thickness of the oxide films were computed and compared to those of the bulk oxide. The optical constants of the oxide were found to depend on the thickness of the film and the identity of the alloying addition in the …
-
Optical Properties of Organic Semiconductors: from Submonolayers to Crystalline Films
We have measured the optical properties of films of the organic semiconductors PTCDA (3,4:9,10-perylene-tetracarboxylic dianhydride) and HBC (peri-hexabenzocoronene), prepared by Organic Molecular Beam Expitaxy (OMBE), on different substrates by means of Differential Reflectance Spectroscopy (DRS). …
-
FABRICATION AND OPTICAL RESPONSE OF SILVER NANOWIRE METAMATERIALS
… they can potentially provide in designing the optical response of a material. Engineering of the electromagnetic subunits means that the optical constants of a fabricated medium are not restricted to the limits encountered in nature. Metamaterials operational at visible frequencies require …
-
Surface-enhanced Raman scattering and electron spectroscopic studies of copper and silver surfaces.
… second set of experiments involved measuring the optical properties of the Pb-modified Cu and Ag surfaces using electron energy loss spectroscopy in the reflection mode (REELS). Based on electromagnetic (EM) theory, the enhancement is, to a rough approximation, indirectly proportional to ε₂, the …
-
Optical absorption measurements on silver halides in the ultraviolet and extreme ultraviolet energy ranges
… for measurements in the high energy range. Optical constants have been calculated over the extended energy range, 3.5 to 240 electron volts. Band gaps have been estimated from the ultraviolet energy data and exciton binding energies. Comparison of ultraviolet structure and extreme …
-
Optical modeling off-stoichiometric amorphous Al2O3 thin films deposited by reactive sputtering
… brought up by previous research about how the optical properties of alumina droplets/particles found in solid rocket motors are related to their stoichiometry. We approached this question by adopting methods common in thin film technology. Alumina/aluminum/off-stoichiometric thin films were …
-
Excitons in the thallous halides
… has been developed and has facilitated the optical and magneto-optical experiments on the Thallous Halides. The strain reduction achieved has revealed optical spectra of exceptional sharpness, Previously undiscovered absorption features have appeared and exciton effects have been …
-
Microreflectance and ellipsometric studies on the polished surfaces of some minerals
The optical properties of a series of ore minerals are assessed using microscope photometry and ellipsometry. Results from both methods are compared and any discrepancies in the data are Interpreted within the experimental and instrumental constraints of the two techniques. The errors involved in …
-
Novel characterization of materials using THz spectroscopic techniques
… domain waveforms are measured and the complex optical constants are deduced directly without resorting to the Kramers-Kronig Analysis. In this work, THz spectroscopy has been used to characterize different types of materials. Materials investigated consisted of semiconductors, gate dielectric …
-
Growth and Characterization of (InGa)2O3 Alloys
… in heterostructures in which the electrical and optical properties can be tuned. While research has been concentrated on the development and understanding of the properties of In2O3 and Ga2O3 thin films, there is a need to develop an understanding of the structure and behavior of alloys composed …
-
Plasmonic and Superconducting Self-Assembled MBE Grown Indium Islands
… grown silver films have been shown to possess optical constants closer to that of intrinsic silver leading to lower losses and thus allowing for higher quality plasmonics. MBE has also been used to grow silver nanocrystals and indium droplets, or islands, for plasmonics. These self-assembled …
-
Carbon stars and silicon carbide
… both position and time. We then examine existing optical constants for SiC, and obtain a new set of optical properties that eliminates limitations in the older data. Finally, we use small-particle absorption and scattering theory to produce a program which allows us to apply commonly used shape …
-
Light scattering from tantalum diselenide
… a band gap seen in thermoreflectance data. The optical constants have also been measured. A dip in the real part of the dielectric constant also occurs in the yellow part of the spectrum, and is related to the observed luminescence and resonance effects.
-
Scandium Oxide Thin Films and Their Optical Properties in the Extreme Ultraviolet
This study reports on the physical and optical characterization of scandium oxide thin films. Thin films of scandium oxide, 20-40 nm thick, were deposited on silicon wafers, quartz slides, and silicon photodiodes by reactively sputtering scandium in an oxygen environment. These samples were …
-
Bridging the Modeling-Sampling Gap for Mid-Infrared Reflectance Spectroscopy of Small Particles, Films, and Fibers
… regions, at coverages of less than 1 monolayer. Optical constants were calculated from these measurements, differing by a factor of 2-4 less than that in the literature. To test if the origin of the reduced cross-section was an electric field effect related to the surface selection rule, …
-
Deposition, Characterization, and Fabrication of a Zinc Oxide Piezoelectric Thin Film Microspeaker Using DC Reactive Sputtering
… approach was taken and the structural, optical, electrical, and piezoelectric properties of the ZnO were investigated. Scanning electron microscopy, x-ray diffraction, and atomic force microscopy were utilized to discover the ZnO’s structural properties. Using the XRD and SEM, the …
-
Metrology of very thin silicon epitaxial films
… 700 - 900° C. The effect of heavy doping on the optical properties of crystalline silicon in the spectral range 0.73 - 3.3 eV is precisely described by the Drude free carrier model. It is shown that visible-NIR SE can simultaneously determine the substrate dopant concentration, the thicknesses of …
-
Multilayer solar selective coatings for high temperature solar applications: from concept to design
… contains aspects of very high novelty including optical simulation, coating deposition using cathodic vacuum arc (CVA) and advanced characterization. The computer program CODE was used to simulate the reflectance spectra of different complete coating. Simulated reflectance spectra were compared …
Page 1 of 2