# Tracking Attosecond Electronic Coherences Using Phase-Manipulated Extreme Ultraviolet Pulses

## TL;DR

This paper demonstrates a method to directly control and manipulate the phase of XUV pulses in a sequence, enabling advanced nonlinear spectroscopy and coherent control of electronic states with high temporal resolution.

## Contribution

It introduces a phase-stabilized, phase-modulated XUV-pump, XUV-probe technique that overcomes previous experimental challenges in controlling XUV pulse sequences.

## Key findings

- Directly probes evolution and dephasing of electronic coherence
- Avoids XUV optics for pulse manipulation
- Enables advanced nonlinear spectroscopy at XUV wavelengths

## Abstract

The recent development of ultrafast extreme ultraviolet (XUV) coherent light sources bears great potential for a better understanding of the structure and dynamics of matter. Promising routes are advanced coherent control and nonlinear spectroscopy schemes in the XUV energy range, yielding unprecedented spatial and temporal resolution. However, their implementation has been hampered by the experimental challenge of generating XUV pulse sequences with precisely controlled timing and phase properties. In particular, direct control and manipulation of the phase of individual pulses within a XUV pulse sequence opens exciting possibilities for coherent control and multidimensional spectroscopy, but has not been accomplished. Here, we overcome these constraints in a highly time-stabilized and phase-modulated XUV-pump, XUV-probe experiment, which directly probes the evolution and dephasing of an inner subshell electronic coherence. This approach, avoiding any XUV optics for direct pulse manipulation, opens up extensive applications of advanced nonlinear optics and spectroscopy at XUV wavelengths.

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Source: https://tomesphere.com/paper/1906.07112