Stability Estimates for Phase Retrieval from Discrete Gabor Measurements

Journal of Fourier Analysis and Applications - We prove a sharp general inequality estimating the distance of two probability measures on a compact Lie group in the Wasserstein metric in terms of...     

Time-resolved thermoreflectivity of thin gold films and its dependence on film thickness

\valunit{10}{nm} to have been measured by femtosecond time-resolved pump-probe experiments. A conspicuous change of the relaxation behavior was found around for pump pulse fluences of . Thicker films show a nearly exponential decay of the transient linear reflectivity, which turns into a linear decay during the first for films with thicknesses of or less. This observation is evidence of a mean free path of about for hot electrons with temperatures around . Received: 17 December 1996     

The role of electron-phonon coupling in femtosecond laser damage of metals

Femtosecond laser pulses were applied to study the energy deposition depth and transfer to the lattice for Au, Ni, and Mo films of varying thickness. The onset of melting, defined here as damage threshold, was detected by measuring changes in the scattering, reflection and transmission of the incident light. Experiments were done in multi-shot mode and single-shot threshold fluences were extracted by taking incubation into account. Since melting requires a well-defined energy density, we found the threshold depends on the film thickness whenever this is smaller than the range of electronic energy transport. The dependence of the threshold fluence on the pulse length and film thickness can be well described by the two-temperature model, proving that laser damage in metals is a purely thermal process even for femtosecond pulses. The importance of electron-phonon coupling is reflected by the great difference in electron diffusion depths of noble and transition metals.