Nanometer tip-based ultrafast electron sources : emission processes and direct pulse characterization techniques
Abstract/Contents
- Abstract
- Since the first half of the 20th century, metal tips ending in hemispheres with a radius of curvature of hundreds of nanometers or less have been used as stochastic field emission electron sources because the small radius of curvature allows the application of very strong electric fields to the tip apex. These tips are high brightness electron sources because they have very small virtual source sizes-typically smaller than the tip radius. In this work, field emission tips are operated as pulsed electron sources triggered by a femtosecond laser; thus, the temporal profile of the electron emission is determined by the laser pulse, but the source size is much smaller than the diffraction-limited laser focal spot. Furthermore, due to optical field enhancement at the tip apex, it is possible to get into the strong field regime, where electron emission happens on a time-scale shorter than the optical period. Possible applications of these sources include ultrafast x-ray tubes, improved ultrafast time-resolved electron microscopy and diffraction, injectors for laser accelerators, and quantum optics experiments with time-tagged electrons. The first part of this thesis presents a unified picture of the ultrafast laser-induced emission processes (photo-assisted field emission, multiphoton emission and strong field photoemission, thermally enhanced field emission) and experimental characterization of these processes. The second half describes two ongoing experiments that seek to directly characterize the electron pulses in time. The first is based on streaking the bias field of the tip, which maps the electron emission time onto electron kinetic energy. The second is a cross-correlator for electrons and photons, where an electron absorbs a photon in the near field created by scattering light from a nanostructure. These experiments will constitute not only the first direct measurement of the electron pulse duration in this system but will also point the way towards new techniques for manipulating ultrafast electron pulses with optical and microwave fields.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Kealhofer, Catherine |
|---|---|
| Associated with | Stanford University, Department of Physics. |
| Primary advisor | Kasevich, Mark A |
| Thesis advisor | Kasevich, Mark A |
| Thesis advisor | Bucksbaum, Philip H |
| Thesis advisor | Byer, R. L. (Robert L.), 1942- |
| Advisor | Bucksbaum, Philip H |
| Advisor | Byer, R. L. (Robert L.), 1942- |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Catherine Kealhofer. |
|---|---|
| Note | Submitted to the Department of Physics. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2013. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2013 by Catherine Morgan Kealhofer
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