Status and prospects of x-ray free-electron lasers (X-FELs): a simple presentation

Abstract

The first part of this topical review provides the reader with a conceptual background sufficient to understand the mechanism of an X-FEL without using any formalism. The discussion is thus accessible to non-specialized scientists from any discipline. Then, we review the present status of selected X-FEL projects throughout the world. Examples of actual experiments are used to illustrate the potential impact of these new, exciting sources at the forefront of photon technology.

An ultrashort pulse ultra-violet radiation undulator source driven by a laser plasma wakefield accelerator

“…1,2 It has been proposed as a compact driver of undulator radiation, [3][4][5] which has recently been demonstrated initially in the visible 6 and then in the extreme ultra-violet 7 spectral range. The high peak current, quasi-monoenergetic, and ultrashort electron bunches ensure an inherently high peak brilliance source of undulator radiation 8 tuneable over a wide spectral range.…”

“…LWFAs could ultimately serve the large user communities of nextgeneration synchrotron and free-electron laser (FEL) light sources at shorter wavelengths. 8,9 However, of immediate interest in the VUV range are applications in ultrafast spectroscopy 10,11 of photo-and biochemical processes, including femtochemistry 12 and femtobiology, 13 that require a temporal resolution of 10 fs or less. The prospect of a LWFAdriven VUV undulator radiation source for such applications is demonstrated by simulations of our electron beam transport, carried out using the General Particle Tracer (GPT) code 14 and presented in Fig.…”

X-ray Diffraction: A Powerful Technique for the Multiple-Length-Scale Structural Analysis of Nanomaterials

“…These materials require the use of coherent X-rays available at dedicated synchrotron radiation beamlines or Free Electron Lasers [72]. In Figure 10 a schematic description of a SAXS experiment with a coherent X-ray beam is provided, to introduce the concept of speckled SAXS pattern.…”

Echo-Enabled Harmonic Generation Studies for the FERMI Free-Electron Laser

“…At present, free-electron lasers (FELs), which amplify the light emitted by relativistic electrons wiggling inside a periodic magnetic field of an undulator [5], are the only light sources able to generate such pulses [6][7][8][9]. To study femtosecond dynamics with element sensitivity using a resonant pump-resonant probe approach [10] or a nonlinear wave-mixing scheme [11], the light source has to meet even more stringent requirements.…”