Physics Commons^™

Determination Of The Goos-Hänchen Shift In Dielectric Waveguides Via Photo Emission Electron Microscopy In The Visible Spectrum, Theodore Stedmark, Robert Campbell Word, Rolf Kӧnenkamp

Physics Faculty Publications and Presentations

Photoemission Electron Microscopy (PEEM) is a versatile tool that relies on the photoelectric effect to produce high-resolution images. Pulse lasers allow for multi-photon PEEM where multiple photons are required excite a single electron. This non-linear process can directly image the near field region of electromagnetic fields in materials. We use this ability here to analyze wave propagation in a linear dielectric waveguide with wavelengths of 410nm and 780nm. The propagation constant of the waveguide can be extracted from the interference pattern created by the coupled and incident light and shows distinct polarization dependence. The electromagnetic field interaction at the boundaries …

Photoemission From Localized Surface Plasmons In Fractal Metal Nanostructures, Robert Campbell Word, Rolf Könenkamp, T. T. Dornan

Physics Faculty Publications and Presentations

We use photoemission microscopy to characterize localized surface plasmon distributions in nanostructured gold layers on indium-tin-oxide/glass substrates. The Au films have a fractal dimension of ∼1.3 and smallest feature sizes of ∼100 nm. We use femtosecond laser pulses at a wavelength of ∼800 nm for the plasmon excitation. Photoelectron emission occurs by a three-photon process in localized areas of indium-tin-oxide with ∼70 nm diameter. In these areas the photoemission rate is enhanced several thousand fold compared to nonstructured surface areas. The results show that plasmon enhanced photoemission can be induced in a nonabsorbing material in proximity to a plasmon-active metal …

An Assessment Of The Transmission Electron Microscope For The Study Of Aerosol-Gas Interactions: Direct Observations Of Sodium Chloride Hydration Phenomena, Antony David Clarke

Dissertations and Theses

An experimental study of solid-gas interactions was made for sodium chloride particles, using a specially fabricated environmental chamber in a transmission electron microscope. It was found that under suitable conditions the hydration and dehydration of these particles could be directly observed and quantitatively measured. Measurements of growth were obtained with a time resolution of one-thirtieth of a second for particles having diameters ranging from 0.02 μm to 1.0 μm.

Crystal Structure Determination Of Β-Lactoglobulin From Electron Micrographs, Richard Roeter

Dissertations and Theses

Often electron micrographs exhibit a repeating structure. Sometimes this repeating structure satisfies the definition of a crystal in that it has a three dimensional repeating structure. If the unit cell structure of this repeating structure can be determined it can be used to help categorize different sections of a particular sample. In some cases, the use of optical diffraction analysis of electron micrographs with repeating structure is a method of determining the unit cell structure.

Samples of β-Lactoglobulin were prepared for viewing in the electron microscope using both the crystalline material and carbon replicas of the crystal surface. Because the …