Attosecond single-cycle undulator light : a review

Research at modern light sources continues to improve our knowledge of the natural world, from the subtle workings of life to matter under extreme conditions. Free-electron lasers, for instance, have enabled the characterization of biomolecular structureswith sub-angstrom spatial resolution, and paved the way to controlling the molecular functions. On the other hand, attosecondtemporal resolution is necessary to broaden our scope of the ultrafast world. Here, we discuss the state-of-the art of ultrashort pulsegeneration and attosecondscience beyond present capabilities. Furthermore, we review three recently proposed methods of generating attosecondx-ray pulses. These novel methods exploit the coherent radiation of microbunched electrons in undulators and the tailoring of the emitted wavefronts. The computed pulse energy outperforms pre-existing technologies by three orders of magnitude. Specifically, our simulations of the proposed Soft X-Ray Laser(SXL) at MAX IV (Lund, Sweden) show that a pulse duration of 50-100 attosecondsand a pulse energy up to 5 microjoules is feasible with the novel methods. In addition, the methods feature pulse shape control, enable the incorporation of orbital angular momentum, and can be used in combination with modern compact free-electron lasersetups. Research at modern light sources continues to improve our knowledge of the natural world, from the subtle workings of life to matter under extreme conditions. Free-electron lasers, for instance, have enabled the characterization of biomolecular structureswith sub-angstrom spatial resolution, and paved the way to controlling the molecular functions. On the other hand, attosecondtemporal resolution is necessary to broaden our scope of the ultrafast world. Here we discuss attosecondpulse generation beyond present capabilities. Furthermore, we review three recently proposed methods of generating attosecondx-ray pulses. These novel methods exploit the coherent radiation of microbunched electrons in undulators and the tailoring of the emitted wavefronts. The computed pulse energy outperforms pre-existing technologies by three orders of magnitude. Specifcally, our simulations of the proposed Soft XRay Laser (SXL) at MAX IV (Lund, Sweden) show that a pulse duration of 50-100 attosecondsand a pulse energy up to 5 microjoules is feasible with the novel methods. In addition, the methods feature pulse shape control, enable the incorporation of orbital angular momentum, and can be used in combination with modern compact free-electron lasersetups.