Abstract

We present the design, the fabrication and the characterization of non-periodic multilayer mirrors for the compression of attosecond pulses generated by a high harmonic source. A first set of mirrors have been optimized to get a reflectivity higher than 10% over the energy range 35-55 eV, and a negative group delay dispersion, in order to compensate for the intrinsic positive chirp of the source. A second set of mirrors have been optimized by using a time domain approach, in the 20-120 eV range, to get sub-50 as pulse duration when combined with a broadband hybrid filter. At wavelength characterizations have been performed both on an attosecond source and on synchrotron radiation source using a variety of techniques. The agreement with theoretical calculation is excellent. These results show that non-periodic multilayer mirrors provide an efficient way to compress attosecond pulses in the XUV spectral domain.

© 2011 Optical Society of America