Abstract
We study carrier-envelope phase (CEP) -dependent photoelectron momentum distributions (PEMDs) generated by strong-field ionization of Xe atoms with linearly polarized sub-two-cycle near-infrared laser pulses. The PEMDs in the polarization direction end with a cutoff structure whose position and shape are analyzed using the adiabatic theory of rescattering [T. Morishita and O. I. Tolstikhin, Phys. Rev. A 96, 053416 (2017)]. This theory predicts that the cutoff, wherein the PEMD begins to exponentially decay, is located at a quantum caustic that is shifted towards higher energies with respect to the corresponding classical caustic at which long and short backward rescattering trajectories coalesce. The observed position of the cutoff in the PEMDs agrees well with the adiabatic theory, confirming the quantum shift of the caustic. This result paves the way to a more accurate procedure for extracting electron-ion elastic scattering differential cross sections from CEP-dependent cutoffs in strong-field PEMDs.
- Received 9 March 2021
- Accepted 15 April 2021
DOI:https://doi.org/10.1103/PhysRevA.103.043121
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