arXiv subjects

Eric R. Jones

Publications and source records attributed to Eric R. Jones.

3 recordsLinked to original sources

arXiv2021

Laser-induced electron emission from Au nanowires: A probe for orthogonal polarizations

Photoelectron field emission, induced by femtosecond laser pulses focused on metallic nanotips, provides spatially coherent and temporally short electron pulses. The properties of the photoelectron yield give insight into both the material properties of the nanostructure and the exciting laser focus. Ultralong nanoribbons, grown as a single crystal attached to a metallic taper, are sources of electron field emission that have not yet been characterized. In this report, photoemission from gold nanoribbon samples is studied and compared to emission from tungsten and gold tips. We observe that the emission from sharp tips generally depends on one transverse component of the exciting laser field, while the emission of a blunted nanoribbon is found to be sensitive to both components. We propose that this property makes photoemission from nanoribbons a candidate for position-sensitive detection of the longitudinal field component in a tightly focused beam.

physics.app-ph↗

arXiv2019

Partially coherent quantum degenerate electron matter waves

The use of electron beams is ubiquitous; electron microscopy, scanning tunneling microscopy, electron lithography, and electron diffractometry all use well-collimated and focused beams. On the other hand, quantum degenerate electron beams do currently not exist. The realization of such beams may impact all electron beam technologies and are interesting to pursue. Past attempts to reach degeneracy were hampered by the low degeneracy of continuously emitting electron sources. With the recent advent of ultra-short electron pulses, high degeneracy is expected. Coulomb repulsion and low quantum coherence are hurdles that need to be overcome. A quantum analysis of the electron degeneracy for partially coherent pulsed electron sources is presented. Two-particle coincidence spectra are obtained for source parameters that are currently available. The conclusive demonstration of the fermionic Hanbury-Brown Twiss (HBT) effect for free electrons is shown to be within reach, and our results support the claim that femto-second nanotip electron sources, both polarized and unpolarized, can manifest partial to complete quantum degeneracy with appreciable signal-to-noise-ratios for free electron pulses notwithstanding their small particle numbers.

quant-ph↗

arXiv2019

Femtosecond-Laser-Induced Spin-Polarized Electron Emission from a GaAs Tip

It is shown that focusing circularly-polarized 800 nm light pulses of 100 fs duration on the tips of p-GaAs crystalline shards having no negative electron affinity (NEA) activation results in electron emission that is both fast and spin-polarized. The 400 fs duration of the emission process was determined by pump/probe measurements. The three samples we investigated produced electron polarizations of 13.1(9)%, 13.3(7)%, and 10.4(2)%. Emission currents ranged between 50 pA and 3 nA with a sample bias of -100V and average laser power of 100 mW. The electron emission exhibited linear dichroism and was obtained under moderate vacuum conditions, similar to that of metallic tips. This source of spin-polarized electron pulses is "fast" in the sense that the electron emission process is of comparable duration to the laser pulses that initiate it.

physics.optics↗