Circular Holographic Ionization-Phase Meter

Abstract

We propose an attosecond XUV-pump IR-probe photoionization protocol that employs pairs of counter-rotating consecutive harmonics and angularly resolved photoelectron detection, thereby providing direct measurement of ionization phases. The present method, which we call circular holographic ionization-phase meter (CHIP), gives also access to the phase of photoemission amplitudes of even-parity continuum states from a single time-delay measurement, since the relative phase of one-and two-photon ionization pathways is imprinted in the photoemission anisotropy. The method is illustrated with ab initio simulations of photoionization via autoionizing resonances in helium. The rapid phase excursion in the transition amplitude to both the dipole-allowed (2s2p) 1 P o and the dipole-forbidden (2p 2 ) 1 D e states are faithfully reproduced.

Phase delays in $ω-2ω$ above-threshold ionization

“…Two-color (ω − 2ω) laser fields with well-controlled relative phases between both colors have been experimentally and theoretically studied since the last decade of the last century [31][32][33][34][35]. Recently, they have also been employed as alternative tool to extract information on ionization phases and time delays [36][37][38][39]. One key feature is that the broken inversion symmetry of the ω − 2ω field allows for interference between odd and even partial waves of the outgoing photoelectron which leads to a (θ ↔ π − θ) asymmetry of the emission signal.…”

New Method for Measuring Angle-Resolved Phases in Photoemission

“…Usually, the IR pulse is the fundamental of the odd harmonics in the pulse train, although Loriot et al [22] report a variant using the second harmonic. Recent work on phase retrieval includes methods based on photorecombination [13,23], two-color, two-photon ionization via a resonance [24], and a proposal to use successive harmonics of circularly polarized light [25].…”

Reconstruction of attosecond beating by interference of two-photon transitions in the bulk of solids

“…Advances in ultrafast laser technology during the last two decades have given rise to the field of attosecond science -the study and control of electron dynamics at their natural (attosecond) timescale 1,2 . Among the experimental techniques that made this possible, the reconstruction of attosecond beating by interference of two photon transitions (RABBIT) stands out [3][4][5][6][7][8] . Since it uses weak electric fields, it allows one to monitor coherent electronic dynamics that are barely modified by the laser.…”