2017/01/31 by J. G. H. Franssen, T. L. I. Frankort, E. J. D. Vredenbregt +1 · 1 citation
Engineering · Physics and Astronomy · #Atmospheric-pressure laser ionization #Electron #Femtosecond #Ionization #Laser #Laser-Matter Interactions and Applications #Microsecond #Particle Accelerators and Free-Electron Lasers #Photoionization #Quantum chaos and dynamical systems #Ultrashort pulse #physics.acc-ph #physics.atom-ph #physics.plasm-ph
paper · pdf · doi:10.1063/1.4978996
published as Struct. Dyn. 4, 044010 (2017)
openalex created_date 2017/02/03 · arxiv created 2017/02/27 · openalex publication_date 2017/03/23 · arxiv updated 2017/03/24 · openalex updated_date 2026/08/05
We present measurements of the pulse length of ultracold electron bunches generated by near-threshold two-photon photoionization of a laser-cooled gas. The pulse length has been measured using a resonant 3 GHz deflecting cavity in TM110 mode. We have measured the pulse length in three ionization regimes. The first is direct two-photon photoionization using only a 480 nm femtosecond laser pulse, which results in short (∼15 ps) but hot (∼104 K) electron bunches. The second regime is just-above-threshold femtosecond photoionization employing the combination of a continuous-wave 780 nm excitation laser and a tunable 480 nm femtosecond ionization laser which results in both ultracold (∼10 K) and ultrafast (∼25 ps) electron bunches. These pulses typically contain ∼103 electrons and have a root-mean-square normalized transverse beam emittance of 1.5 ± 0.1 nm rad. The measured pulse lengths are limited by the energy spread associated with the longitudinal size of the ionization volume, as expected. The third regime is just-below-threshold ionization which produces Rydberg states which slowly ionize on microsecond time scales.