Spectro-temporal shaping of seeded free-electron laser pulses

TL;DR

This paper demonstrates control over the spectro-temporal properties of XUV pulses from a seeded FEL by manipulating seed laser chirp, enabling precise pulse shaping and coherence verification, advancing applications in nonlinear optics and quantum control.

Contribution

It introduces a method to shape FEL pulses spectro-temporally via seed laser chirp manipulation and confirms the full temporal coherence of FEL light.

Findings

Spectro-temporal control of XUV pulses achieved.

Full temporal coherence of FEL light demonstrated.

Generation of Fourier-limited pulses through phase tuning.

Abstract

We demonstrate the ability to control and shape the spectro-temporal content of extreme-ultraviolet (XUV) pulses produced by a seeded free-electron laser (FEL). The control over the spectro-temporal properties of XUV light was achieved by precisely manipulating the linear frequency chirp of the seed laser. Our results agree with existing theory, which allows retrieving the temporal properties (amplitude and phase) of the FEL pulse from measurements of the spectra as a function of the FEL operating parameters. Furthermore, we show the first direct evidence of the full temporal coherence of FEL light and generate Fourier limited pulses by fine-tuning the FEL temporal phase. The possibility to tailor the spectro-temporal content of intense short-wavelength pulses represents the first step towards efficient nonlinear optics in the XUV to X-ray spectral region and will enable precise manipulation of core-electron excitations using the methods of coherent quantum control.