Multilayer Mirrors for Attosecond Pulse Shaping between 30 and 200 eV

Attosecond (as) physics has become a wide spreaded and still
growing research field over the last decades. It allows for probing
and controlling core- and outer shell electron dynamics with never
before achieved temporal precision. High harmonic generation in
gases in combination with advanced extreme ultraviolet (XUV )
optical components enable the generation of isolated attosecond
pulses as required for absolute time measurements. But until
recently, single attosecond pulse generation has been restricted to
the energy range below 100 eV due to the availability of sources
and attosecond optics. Multilayer mirrors are the up to date widest
tunable optical components in the XUV and key components in
attosecond physics from the outset. In this thesis, the design,
fabrication and measurement of periodic and aperiodic XUV
multilayer mirrors and their application in the generation and
shaping of isolated attosecond pulses is presented. Two- and three
material coatings based on a combination of molybdenum, silicon,
boron carbide, lanthanum and scandium covering the complete
spectral range between 30 and 200 eV are developed and
characterized. Excellent agreement between reflectivity simulations
and experiments is based on the highly stable ion beam sputter
deposition technique. It allows for atomically smooth deposition
and the realization of aperiodic multilayer structures with high
precision and reproducibility. XUV reflectivity simulation of
lanthanum containing multilayer coatings are based on an improved
measured set of optical constants, introduced in this thesis. This
work enabled the generation of the shortest ever measured isolated
light pulses so far, the creation of the first isolated attosecond
pulses above 100 eV , the first demonstration of absolute control
of the “attochirp” by means of multilayer mirrors and the formation
of spectrally cleaned attosecond pulses, in a spectral region which
lacks appropriate filter materials, for a never before achieved
combination of spectral and temporal resolution at 125 eV . Here
presented concepts are in principle not restricted to specific
energies or experimental set-ups and may be extended in the near
future to enter completely new regimes of ultrashort physics.