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Optics

Portland State University

Photoemission

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Full-Text Articles in Physics

Observation And Control Of Photoemission And Electric Field Enhancement Of Plasmonic Antennas Through Photoemission Electron Microscopy, Christopher M. Scheffler Jun 2022

Observation And Control Of Photoemission And Electric Field Enhancement Of Plasmonic Antennas Through Photoemission Electron Microscopy, Christopher M. Scheffler

Dissertations and Theses

Photoemission electron microscopy (PEEM) is an imaging method which uses electrons excited through the photoelectric effect to characterize a sample surface with nanometer-level resolution. In PEEM, a high intensity laser excites electrons from the surface of the material and electron optics are used to form an image from the intensity and spatial distribution of the photoemission from the sample. The goal of this research was to study and maximize light confinement, which was accomplished using plasmonic nanostructures. Surface plasmons represent oscillations in the electron density of a material and can occur along the transition interface between a metal and a …


Simulation Of Light Propagation Captured By Photoemission Electron Microscopy (Peem), Nabila Islam Jul 2021

Simulation Of Light Propagation Captured By Photoemission Electron Microscopy (Peem), Nabila Islam

Dissertations and Theses

The Photoemission electron microscopes (PEEM) is a powerful tool capable of synchronously imaging wave nature of light manifested by interference patterns as well as its particle nature through the energy exchange between the incident photons and the photoemitted imaging electrons. PEEM offers a non-invasive high-resolution approach for studying light propagation and interaction phenomena within a nanophotonic waveguide [7,8]. The electric field intensity variation of the interference pattern yielded by the interaction between the incident light and the guided mode coupled into the waveguide produces varying photoemission yields creating contrast in PEEM image. The guided modes cannot be excited simply by …


Photoemission Electron Microscopy For Analysis Of Dielectric Structures And The Goos-Hänchen Shift, Theodore Axel Stenmark Jun 2016

Photoemission Electron Microscopy For Analysis Of Dielectric Structures And The Goos-Hänchen Shift, Theodore Axel Stenmark

Dissertations and Theses

Photoemission Electron Microscopy (PEEM) is a versatile tool that relies on the photoelectric effect to produce high-resolution electron images. Ultrafast pulse lasers allow for multi-photon PEEM where multiple visible or IR photons excite a single electron in a nonlinear process. The photoelectron yield in both cases is related to the near-field region of electromagnetic fields at the surface of the sample. We use this ability here to analyze wave propagation in a linear dielectric waveguide with wavelengths of 410 nm and 780 nm. The propagation constant of the waveguide can be extracted from interference patterns created by light propagating in …


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 Feb 2016

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 …


Direct Coupling Of Photonic Modes And Surface Plasmon Polaritons Observed In 2-Photon Peem, Robert Campbell Word, Joseph Fitzgerald, Rolf Könenkamp Dec 2013

Direct Coupling Of Photonic Modes And Surface Plasmon Polaritons Observed In 2-Photon Peem, Robert Campbell Word, Joseph Fitzgerald, Rolf Könenkamp

Physics Faculty Publications and Presentations

We report the direct microscopic observation of optical energy transfer from guided photonic modes in an indium tin oxide (ITO) thin film to surface plasmon polaritons (SPP) at the surfaces of a single crystalline gold platelet. The photonic and SPP modes appear as an interference pattern in the photoelectron emission yield across the surface of the specimen. We explore the momentum match between the photonic and SPP modes in terms of simple waveguide theory and the three-layer slab model for bound SPP modes of thin metal films. We show that because the gold is thin (30- 40 nm), two SPP …