Abstract

In the first decade of the 21^st century rapid development of laser- and accelerator- based light sources (high-harmonic generation and free-electron lasers (FEL)) enabled generating ultra-intense and ultra-short extreme-ultra-violet (EUV) or soft X-ray pulses. This substantially extended the borders of the ultrafast science, providing a basis for a variety of novel time-resolved schemes (including e.g., attosecond soft X-ray / infrared (IR) [1] or femtosecond EUV / EUV [2] pump-probe experiments), and triggered a number of fundamental studies on light-induced non-linear processes in this energy range. The next milestone has been achieved when the first X-ray FEL, Linac Coherent Light Source (LCLS) at Stanford has become operational in 2009 [3]. This machine, currently delivering few mJ 5-500 fs pulses at photon energies up to 8 KeV, brought non-linear optics into the X-ray domain, and opened a way for numerous exciting applications ranging from atomic and molecular physics to material science and biology.

© 2011 Optical Society of America