Using a passively stable attosecond beamline for relative photoemission time delays at high XUV photon energies

Abstract

We present and demonstrate an experimental scheme that enables overlap-free reconstruction of attosecond beating by the interference of two-photon transition (RABBITT) measurements at high extreme-ultraviolet (XUV) photon energies. A compact passively-stabilized attosecond beamline employing a multilayer (ML) mirror allows us to obtain XUV pulses consisting of only two odd high-harmonic orders from an attosecond pulse train (APT). We compare our new technique to existing schemes that are used to perform RABBITT measurements and discuss how our scheme resolves the limitations imposed by spectral complexity of the harmonic comb at high photon energies. We further demonstrate first applications of our scheme for rare gases and gas mixtures, and show that this scheme can be extended to gas-molecule mixtures.

Photoionization of Xe and Xe@C60 from the 4d shell in RABBITT fields

“…We hope that the present work will guide the new generation of RABBITT measurements accessing very large sideband orders and deeper atomic shells. These measurements have been reported in the literature very recently [7,14,15]. In heavier atoms and deeper atomic shells such as Xe 4d, the spin-orbit splitting effects become noticeable.…”

“…Recently, this technique has become angular resolved [11][12][13]. While the initial studies have been confined to a narrow photon energy range not exceeding 40 eV (24th harmonic of the fundamental radiation at λ 800 nm), the most recent experiments [7,14,15] extended this range above 100 eV. This has enabled the study of photoemission dynamics beyond the outer atomic shells and to probe the subvalent 4d shell of the Xe atom [14].…”

Attosecond interferometry of shape resonances in the recoil frame of CF 4

“…Parameters that were varied are the HHG phase-matching conditions, such as the xenon gas pressure and the IR intensity, the metallic filter (either Al or Sn), the electric extraction field in the COLTRIMS, and the magnetic field. The data were then analyzed for argon and CF 4 separately using a CVPCA, which has been introduced by Jordan and Wörner (35) and since then successfully used to extract phases in spectrally congested time-resolved electron spectra (48)(49)(50). The CVPCA is implemented as follows.…”

Relativistic Two-photon Matrix Elements for Attosecond Delays

“…The delay difference between photoelectrons originating from the outermost p 3/2 and p 1/2 orbitals in Krypton and Xenon have been studied in Ref. [71,72], using the interferometric RABBITT technique. In Fig.…”

“…While RRPA theory was originally developed in the late seventies by Johnson and Cheng to describe one-photon ionization cross sections in heavy elements [69,70], the interest in such phenomena is revived by recent RABBIT experiments that have targeted heavy elements. Firstly, Jordan et al [71] and Jain et al [72] have compared photoelectrons from the fine-structure split valance orbitals: 4p j and 5p j with j = 1/2 and 3/2 of Krypton and Xenon atoms, respectively, and secondly, Jain et al [73] and Zhong et al [74], have compared photoelectrons from inner orbitals in Xenon, down to the 4d orbital. The 4d orbital is of special interest since it is known to posses a giant collective resonance in the photoionization cross section, as evidenced by MBPT in the early seventies by Amusia and Wendin [75,76].…”