Seminarium: Peter van der Slot, Inst. voor Nanotechnologie, Universiteit Twente
|Wanneer:||di 11-01-2011 om 11:00|
Titel: " Fully coherent EUV radiation from seeded Free-Electron Lasers ”
Free-electron lasers are considered to be the next generation of short-pulse, ultra-bright light sources that will allow investigation of matter at the atomic scale with femtosecond temporal resolution.The shortest wavelength produced so far is 1.5 Å by LCLS, while the seeded FERMI@Elettra free-electron laser recently demonstrated coherent light generation at 43 nm (6th harmonic of seed laser).
In this presentation I will first review the operating principle of a free-electron laser. For long wavelengths, fully coherent light is obtained by configuring the laser with a resonator. However, appropriate mirrors are not readily available in the EUV and x-ray wavelength range. Therefore, most systems rely on self-amplified spontaneous emission in a single pass to operate in this wavelength regime (like LCLS) and the properties of these systems are discussed.To obtain fully coherent light pulses, a seed laser is required. The seeding requirements will be reviewed and direct and sub-harmonic seeding options are presented. Some of these will be tested by us on the FERMI@Elettra free-electron laser in the coming years.