Physical Review Research

Electronic coherences in argon through interfering one- and two-photon ionization processes in the vicinity of Feshbach resonances

Roger Y. Bello, Vicent J. Borràs, Jesús González‐Vázquez, Fernando Martı́n

Published Oct 14, 2022• 11 citations

Abstract

The role of Rydberg autoionizing states in interfering one- and two-photon ionization paths is theoretically investigated in atomic Ar. The angularly resolved photoionization cross sections for each individual path is provided. By varying the relative optical phase between the two pulses the phase difference between the two interfering paths is extracted. The retrieved phase difference and the photoelectron angular distributions exhibit a strong dependence on the photon energy in the vicinity of the resonant states. In contrast to previous results obtained in atomic Ne, the phase difference features a smooth dependence with photoelectron emission angle.

DOI: 10.1103/physrevresearch.4.043028

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Physical Review Research

Electronic coherences in argon through interfering one- and two-photon ionization processes in the vicinity of Feshbach resonances

Roger Y. Bello, Vicent J. Borràs, Jesús González‐Vázquez, Fernando Martı́n

Published Oct 14, 2022• 11 citations

Publisher

Abstract

DOI: 10.1103/physrevresearch.4.043028

Related papers

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Jan 1, 19920 citations

6s6p\text{ }{^{1}P}_{1}

intermediate state electron to an energy between the

5{d}_{3∕2}ϵ

and the

5{d}_{5∕2}ϵ

thresholds with concurrent one-photon and two-photon interactions. The left-right asymmetry of the photoelectron angular distributions for the two energy-resolved product states,

6{s}_{1∕2}ϵ

and

5{d}_{3∕2}ϵ

, show sinusoidal modulation as a function of the relative phase of the $\ensuremath{\omega}\text{\ensuremath{-}}2\ensuremath{\omega}$ fields. The phase difference between these signals, or phase lag, varies rapidly with the laser frequency when the interaction is nearly resonant with autoionizing resonances in the continuum. An exceptionally large phase lag variation of over $2\ensuremath{\pi}$ was measured.

{)}^{1}

P${\mathrm{\ifmmode^\circ\else\textdegree\fi{}}}_{1}$ and the (5d6p

{)}^{1}

P${\mathrm{\ifmmode^\circ\else\textdegree\fi{}}}_{1}$ states are used as intermediates in the photoexcitation of barium to energies in the range of a series of 5dnd autoionizing states. Dramatic differences in the profiles of autoionizing lines are observed for excitation pathways involving different intermediate states. Angular distributions of photoelectrons collected across the range of autoionizing resonances demonstrate strong variations that follow constraints imposed by the angular momentum of the autoionizing peaks and also suggest significant spin-orbit interactions in the photoionization step.

\beta

from its nonrelativistic value of 2. Spin-orbit coupling displaces the minimum in the cross section for excitation to the $\rm \varepsilon P\sb{1/2}$ and $\rm \varepsilon P\sb{3/2}$ and results in a rapid variation of the angular distribution with photon energy in this region. Through the measurement of two-photon ionization angular distributions the quantum defects and spin-orbit coupling were investigated. These studies help us to understand the phase interference interaction, and the data in those studies would be used to analyze the interference processes.