Timescales in the response of materials to femtosecond laser excitation

The interaction of ultrashort laser pulses with materials involves a number of special features that are different from laser–matter interaction for longer pulse durations. For femtosecond laser excitation the fundamental physical processes such as energy deposition, melting, and ablation are separated in time. By choosing proper time windows, the various processes can be investigated separately. We present selected examples of theoretical studies of free electron excitation in metals, timescales of different melting processes, and peculiarities of near-threshold ablation. Depending on the timescales and intensity ranges, the discussed processes are combined in an overall picture of possible pathways of the material from excitation to ablation.

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