title: Visible-laser acceleration of relativistic electrons in a semi-infinite vacuum.
abstract: We demonstrate a new particle acceleration mechanism using 800 nm laser radiation to accelerate relativistic electrons in a semi-infinite vacuum. The experimental demonstration is the first of its kind and is a proof of principle for the concept of laser-driven particle acceleration in a structure loaded vacuum. We observed up to 30 keV energy modulation over a distance of 1000 lambda, corresponding to a 40 MeV/m peak gradient. The energy modulation was observed to scale linearly with the laser electric field and showed the expected laser-polarization dependence. Furthermore, as expected, laser acceleration occurred only in the presence of a boundary that limited the laser-electron interaction to a finite distance.
authors.affiliation: Stanford University, Stanford, California 94305, USA.
authors.forename: T
authors.initials: T
authors.lastname: Plettner
authors.forename: R L
authors.initials: RL
authors.lastname: Byer
authors.forename: E
authors.initials: E
authors.lastname: Colby
authors.forename: B
authors.initials: B
authors.lastname: Cowan
authors.forename: C M S
authors.initials: CM
authors.lastname: Sears
authors.forename: J E
authors.initials: JE
authors.lastname: Spencer
authors.forename: R H
authors.initials: RH
authors.lastname: Siemann