Dynamical Phase Evolution of Coulomb-Focused Electrons in Strong-Field Ionization Probed by a Standing Light Wave
We use an interferometer made of a pulsed standing wave light grating created by colliding two femtosecond laser pulses to measure the time evolution of the phase of a slow photoelectron as it escapes from a Coulomb potential. The technique exploits the Kapitza Dirac effect to diffract the broad-band electron wavepacket. Our findings show that low-energy electrons exhibit a unique chromosome-shaped diffraction pattern, distinct from higher-energy electrons. Our numerical model quantitatively reproduces the experimental results, confirming this pattern maps the electron's time-dependent phase evolution as it escapes from a Coulomb potential. Our pulsed diffraction grating technique offers a new way to sense an electron's quantum phase at very large distances without interfering its release mechanism.
Fig. 1: Time-dependent diffraction fringes for Coulomb-focused electrons.
Publication:
Dynamical Phase Evolution of Coulomb-Focused Electrons in Strong-Field Ionization Probed by a Standing Light Wave
Yuan Gu, Hao Liang, Weiran Zheng, Aofan Lin, Jiaye Zhang, Zichen Li, Juan Du, Lei Ying, Peilun He, Jan‑Michael Rost, Sina Jacob, Maksim Kunitski, Till Jahnke, Sebastian Eckart, Kang Lin, and Reinhard Dörner
DOI: 10.1103/63v1-3b63
Phys. Rev. Lett. 136, 103201 - Published 11 March, 2026
See online:
https://doi.org/10.1103/63v1-3b63
https://journals.aps.org/prl/abstract/10.1103/63v1-3b63
Acknowledgments:
The Frankfurt based work was funded by the European Union (ERC, Timing-FreePhase-Project No. 101141762)