A high-intensity highly coherent soft X-ray femtosecond laser seeded by a high harmonic beam

• Published in: Nature Vol. 431; no. 7007; pp. 426 - 429
• Main Authors: Zeitoun, Ph, Faivre, G, Sebban, S, Mocek, T, Hallou, A, Fajardo, M, Aubert, D, Balcou, Ph, Burgy, F, Douillet, D, Kazamias, S, de Lachèze-Murel, G, Lefrou, T, le Pape, S, Mercère, P, Merdji, H, Morlens, A. S, Rousseau, J. P, Valentin, C
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 23.09.2004; Nature Publishing Group
• Subjects: Biology; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Lasers; Optics; Physics; Research methodology; Scientific apparatus & instruments; X- and γ-ray instruments and techniques; X- and γ-ray lasers; X- and γ-ray sources, mirrors, gratings and detectors; X-rays; Soft X radiation; Radiation sources; X-ray lasers; fs range; Optical harmonic generation; Nonlinear optics; Higher harmonic
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature02883

Synchrotrons have for decades provided invaluable sources of soft X-rays, the application of which has led to significant progress in many areas of science and technology. But future applications of soft X-rays-in structural biology, for example-anticipate the need for pulses with much shorter duration (femtoseconds) and much higher energy (millijoules) than those delivered by synchrotrons. Soft X-ray free-electron lasers should fulfil these requirements but will be limited in number; the pressure on beamtime is therefore likely to be considerable. Laser-driven soft X-ray sources offer a comparatively inexpensive and widely available alternative, but have encountered practical bottlenecks in the quest for high intensities. Here we establish and characterize a soft X-ray laser chain that shows how these bottlenecks can in principle be overcome. By combining the high optical quality available from high-harmonic laser sources (as a seed beam) with a highly energetic soft X-ray laser plasma amplifier, we produce a tabletop soft X-ray femtosecond laser operating at 10 Hz and exhibiting full saturation, high energy, high coherence and full polarization. This technique should be readily applicable on all existing laser-driven soft X-ray facilities.