Andrea Cavalleri

Abstract:

We review the progress we made recently on the generation of a femtosecond thermal X-ray source (line and broadband emissions) using solid-density-plasmas generated by ultrashort laser, in view of applications to molecular dynamic.

Abstract:

Time-resolved x ray diffraction was used to study ultrafast structural transitions in optically excited semiconductors and metals. Non thermal changes in the lattice structure was observed in less than 300 fs. The analysis confirmed the existence of femtosecond non-thermal melting in a covalent semiconductor. The analysis indicated an ultrafast structural transition in a metal.

Abstract:

Using time-resolved x-ray diffraction ultafast lattice dynamics in fs-laser-excited crystalline bulk Ge and Ge/Si-heterostructures has been studied. This experimental technique uniquely allows us to observe fast energy transport deep into. the bulk of the material, coherent acoustic phonon dynamics, lattice anharmonicity, and vibrational transport across a buried interface.

Abstract:

Relatively small-scale laser-driven sources of short wavelength radiation covering a range from the extreme ultraviolet to the hard X-ray regime are now available. Because the duration of the X-ray pulses is comparable to, or shorter than the laser pulse width, it is possible to carry out X-ray measurements with picosecond or femtosecond time resolution.