Observing angular precession of a Rydberg wave packet due to spin-orbit coupling by orthogonally polarized weak half-cycle pulses

Abstract

Arbor-We investigate the response of an np Rydberg wave packet to orthogonal polarized half-cycle pulses(HCPs) over the course of its field free evolution. The population redistribution from p to s states is highly sensitive to the polarization of HCPs and changes with the precession of the electron orbits due to spin-orbit coupling. The selection rules of HCP redistribution are obtained and an intuitive classical interpretation is given.

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

“…The treatment is similar to the formalism used e.g. in [24,26] and the bright-/dark-state model employed in [11,25,35]. However, the description presented here is specifically adapted to the creation of SOWPs by general polarization-shaped bichromatic laser fields and, moreover, includes the spatial aspects of the SOWP mapped into the 3D photoelectron momentum distribution.…”

“…In this appendix, we provide a rigorous mathematical description of the spatiotemporal electron dynamics in the potassium p 4 fine-structure states excited by a resonant polarization-shaped laser pulse, building on the treatment in [11,24,25,33,35]. We develop an analytical 3D model of the spatial SOWP dynamics (appendix A.1) which is subsequently applied to SOWPs launched by a circularly (appendix A.2) and a linearly polarized (appendix A.3) pump pulse, as used in the experiment.…”

“…SOWPs, being a prototype example of coherent electron dynamics, were among the first electron wave packets studied in realtime. For example, SOWPs have been investigated in Rydberg atoms on the picosecond timescale [22][23][24] and in alkali metals [11,25] and noble gases [26][27][28] on the femtosecond timescale. Recently, the sub-femtosecond motion of SOWPs in krypton ions was observed using attosecond transient absorption spectroscopy [29].…”

“…Recently, the sub-femtosecond motion of SOWPs in krypton ions was observed using attosecond transient absorption spectroscopy [29]. In addition, coherent control of SOWPs based on shaped femtosecond laser pulses was demonstrated [28,[30][31][32] and the polarization dependence of SOWPs was studied experimentally [11,24] and proposed as a means to produce highly spin-polarized electrons [33,34]. So far, the dynamics of SOWPs have mainly been studied by means of scalar observables.…”

“…For example, in [11,25,35], oscillations in the ion yield from multiphotonionization of potassium atoms due to variation of the ionization probability during the SOWP time evolution were measured and analyzed in a bright-/dark-state formalism. However, since SO interaction induces a precession of the electron orbital alignment in angular direction [11,24,33], highly differential detection techniques are required to gain a complete spatiotemporal picture of the coupled angular momentum dynamics. In [26], photoelectron imaging spectroscopy was used to observe the angular dynamics of a SOWP in krypton atoms from linearly polarized excitation and ionization.…”