English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Quantum mechanically, photoionization can be fully described by the complexphotoionization amplitudes that describe the transition between the groundstate and the continuum state. Knowledge of the value of the phase of theseamplitudes has been a central interest in photoionization studies and newlydeveloping attosecond science, since the phase can reveal important informationabout phenomena such as electron correlation. We present a newattosecond-precision interferometric method of angle-resolved measurement forthe phase of the photoionization amplitudes, using two phase-locked ExtremeUltraviolet pulses of frequency $\omega$ and $2\omega$, from a Free-ElectronLaser. Phase differences $\Delta \tilde \eta$ between one- and two-photonionization channels, averaged over multiple wave packets, are extracted forneon $2p$ electrons as a function of emission angle at photoelectron energies7.9, 10.2, and 16.6 eV. $\Delta \tilde \eta$ is nearly constant for emissionparallel to the electric vector but increases at 10.2 eV for emissionperpendicular to the electric vector. We model our observations with bothperturbation and \textit{ab initio} theory, and find excellent agreement. Inthe existing method for attosecond measurement, Reconstruction of AttosecondBeating By Interference of Two-photon Transitions (RABBITT), a phase differencebetween two-photon pathways involving absorption and emission of an infraredphoton is extracted. Our method can be used for extraction of a phasedifference between single-photon and two-photon pathways and provides a newtool for attosecond science, which is complementary to RABBITT.

A new method for measuring angle-resolved phases in photoemission