Attosecond pulse characterization with coherent Rydberg wavepackets

TL;DR

This paper introduces a novel method for characterizing ultrafast extreme ultraviolet pulses using coherent Rydberg wavepackets, enabling phase retrieval by analyzing quantum beats in photoelectron spectra.

Contribution

It presents a new technique that leverages atomic Rydberg wavepackets to fully reconstruct the temporal structure of EUV pulses, overcoming phase measurement challenges.

Findings

Angle integration removes dipole phase influence.

Rydberg wavepackets provide clear quantum beat signals.

Multiple electronic states enable cross-checking of phase reconstruction.

Abstract

We propose a new technique to fully characterize the temporal structure of extreme ultraviolet pulses by ionizing a bound coherent electronic wavepacket. The populated energy levels make it possible to interfere different spectral components leading to quantum beats in the photoelectron spectrum as a function of the delay between ionization and initiation of the wavepacket. The influence of the dipole phase, which is the main obstacle for state-of-the-art pulse characterization schemes, can be eliminated by angle integration of the photoelectron spectrum. We show that particularly atomic Rydberg wavepackets are ideal and that wavepackets involving multiple electronic states provide redundant information which can be used to cross-check the consistency of the phase reconstruction.