Control of three-dimensional electron vortices from femtosecond multiphoton ionization

Time-resolved 3D imaging of ultrafast spin–orbit wave packet dynamics

“…Additional pathways to a p-type continuum (via s-and d-type intermediates) are not shown but included in the numerical simulations presented in section 4 (see figures 5 and 6). Even though these pathways are typically less efficient due to propensity rules [36,37], the photoelectron wave packet is, in general, described by a coherent superposition of a p-and an f-wave [20,21,38].…”

“…In the experiments reported here, 45 projections were measured for rotation angles between −90°and 86°. From the recorded two-dimensional projections, the 3D-EDs are retrieved using the Fourier slice algorithm [21,45].…”

“…In this contribution, we present a technique for time-resolved 3D reconstruction of ultrafast quantum dynamics by combining the aforementioned advantages of polarization-shaped pulses and highly differential photoelectron detection. The technique is based on the combination of bichromatic polarization pulse shaping, for the generation of polarization-shaped two-color pump-probe pulse sequences, with photoelectron imaging tomography to reconstruct the full energy and angular distribution of photoelectron wave packets released by the probe [19][20][21]. The experimental scheme has been introduced in [20] and applied to the coherent control of photoelectron momentum distributions aiming at the design of unusual angular momentum superposition states.…”

Modeling tomographic measurements of photoelectron vortices in counter-rotating circularly polarized laser pulses

“…One particularly useful arrangement of pulses, namely a pair of time-delayed counter-rotating circular pulses, has become a prominent tool for influencing ionization dynamics in a range of atomic and molecular targets. Such a setup creates interference between wavepackets of differing magnetic quantum number, which is manifest in photoelectron momentum distributions in the form of spiral vortices [10][11][12]. When the pulses are of different colors, this scheme also has important implications for high-order harmonic generation (HHG), and has long been recognized as a source of elliptically polarized attosecond pulse trains [13][14][15][16][17][18][19][20].…”

“…We present a comparison of the measured photoelectron momentum distribution of Ref. [11] with that predicted using RMT. More specifically, we compare our calculated distributions with those measured in a set of planes in momentum space, which are ultimately used for tomographic reconstruction of the entire three-dimensional momentum distribution.…”