0.5 keV soft X-ray attosecond continua

TL;DR

This paper demonstrates the generation of 0.5 keV soft X-ray attosecond supercontinua with high flux and temporal precision, enabling element-specific ultrafast probing in materials science.

Contribution

It introduces a novel transient phase matching regime to produce high-energy soft X-ray supercontinua with controlled pulses and high photon flux.

Findings

Generated soft X-ray supercontinua up to 0.5 keV energy.

Achieved attosecond pulses with 13 as transform limit.

Produced flux of approximately 7.3 x 10^7 photons per second.

Abstract

Attosecond light pulses in the extreme ultraviolet have drawn a great deal of attention due to their ability to interrogate electronic dynamics in real time. Nevertheless, to follow charge dynamics and excitations in materials, element selectivity is a prerequisite, which demands such pulses in the soft X-ray region, above 200 eV, to simultaneously cover several fundamental absorption edges of the constituents of the materials. Here, we experimentally demonstrate the exploitation of a transient phase matching regime to generate carrier envelope controlled soft X-ray supercontinua with pulse energies up to 2.9 +/- 0.1 pJ and a flux of (7.3 +/- 0.1)x10^7 photons/s across the entire water window and attosecond pulses with 13 as transform limit. Our results herald attosecond science at the fundamental absorption edges of matter by bridging the gap between ultrafast temporal resolution and element specific probing.