The book reviews the most recent achievements in optical technologies for XUV and X-ray coherent sources. Particular attention is given to free-electron-laser facilities, but also to other sources available at present, such as synchrotrons, high-order laser harmonics and X-ray lasers. The optical technologies relevant to each type of source are discussed. In addition, the main technologies used for photon handling and conditioning, namely multilayer mirrors, adaptive optics, crystals and gratings are explained. Experiments using coherent light received during the last decades a lot of attention for the X-ray regime. Strong efforts were taken for the realization of almost fully coherent sources, e.g. the free-electron lasers, both as independent sources in the femtosecond and attosecond regimes and as seeding sources for free-electron-lasers and X-ray gas lasers. In parallel to the development of sources, optical technologies for photon handling and conditioning of such coherent and intense X-ray beams advanced. New problems were faced for the realization of optical components of beamlines demanding to manage coherent X-ray photons, e.g. the preservation of coherence and time structure of ultra short pulses.

Master the physics and understand the current applications of modern X-ray and EUV sources with this fully updated second edition.

These proceedings comprise of invited and contributed papers presented at the 13th International Conference on X-Ray Lasers (ICXRL 2012) which was held 11–15 June 2012 in Paris, France, in the famous Quartier Latin, inside the historical Center of Cordeliers. This conference is part of a continuing series dedicated to recent developments and applications of x-ray lasers and other coherent x-ray sources with attention to supporting technologies and instrumentation. New results in the generation of intense coherent x-rays and progress towards practical devices and their applications are reported in these proceedings, including areas of research in plasma-based x-ray lasers, 4th generation accelerator-based sources and higher harmonic generation. Recent achievements related to the increase of the repetition rate up to 100 Hz and shorter wavelength collisional plasma-based soft x-ray lasers down to about 7 nm are presented. Seeding the amplifying plasma with a femtosecond high-order harmonic of infrared laser was foreseen as the required breakthrough to break the picosecond frontier. Numerical simulations based on the Maxwell-Bloch model are presented in these proceedings, transposing the chirped pulse amplification technique to the x-ray domain in order to increase the time over which the femtosecond seed can be amplified. These proceedings also include innovative applications of soft x–ray lasers based on techniques and diagnostics relevant to topical domains such as EUV lithography, inertial confinement fusion, or warm dense matter physics.

This thesis discusses the power scaling of ultrashort pulses in enhancement cavities, utilized in particular for frequency conversion processes, such as Thomson scattering and high-harmonic generation. Using custom optics for ultrashort-pulse enhancement cavities, it demonstrates for the first time that at the envisaged power levels, the mitigation of thermal effects becomes indispensable even in cavities comprising solely reflective optics. It also studies cavities with large beams, albeit with low misalignment sensitivity, as a way to circumvent intensity-induced mirror damage. Average powers of several hundred kilowatts are demonstrated, which benefit hard x-ray sources based on Thomson scattering. Furthermore, pulses as short as 30 fs were obtained at more than 10 kW of average power and employed for high-harmonic generation with photon energies exceeding 100 eV at 250 MHz repetition rate, paving the way for frequency comb spectroscopy in this spectral region.

Up-to-date accounts of recent and future advances in short-wavelength spectroscopy of laboratory and cosmic plasmas.

High harmonic generation (HHG) is a fascinating strong-field physics phenomenon that occurs when a laser pulse with a moderate intensity interacts with atoms and partially ionizes the atoms. A series of harmonics are generated at similar efficiencies and extend to a few tenth, even thousandth, order harmonics at the extreme ultraviolet (EUV) and soft X-ray range. Such an unprecedented broadband and coherent spectrum thus has many novel applications, one of which is to build tabletop coherent EUV and soft X-ray sources. The development of EUV and soft X-ray lasers is very challenging because of the strong absorption of these wavelengths in almost all materials and the lack of appropriate reflection optics. So far, bright coherent EUV and soft X-ray sources are only available at several large-scale facilities, like free-electron lasers. However, the demands for coherent EUV sources is growing due to the advances in atomic physics, chemistry, and material science. Therefore, lab-scale EUV sources are highly desirable for these novel applications and research opportunities, and HHG emerges as a promising technology toward this goal. This thesis will present my PhD work on HHG. It includes the numerical models developed to simulate HHG either on single-atom scale or for a macroscopic medium, the modification to the current theoretical model, the analysis of the influence of plasma defocusing on HHG, the study of the wavelength scaling of HHG efficiency and cutoff with visible and near-infrared (IR) lasers, and the generation of multi-mJ ultrashort mid-IR (2.6 mJ, 39 fs, and 2 tm central wavelength) pulses at kHz repetition rate in the aim of extending the cutoff of HHG. With the kHz mid-IR pulses, an EUV source providing up to 108 photons/sec at 160 eV has been demonstrated, and photons in the water window range have also been detected. At the end, a chapter will summarize these research works and propose some possible future directions.