Physical mechanisms of fused silica restructuring and densification after femtosecond laser excitation [Invited]

We study experimentally the physics of the generation of permanent material restructuring, for the case of fused silica after excitation with intense femtosecond pulses and filaments, in the bulk of the medium. Using a powerful time and spectrally resolved holographic technique we monitor the temporal material evolution from the initial electronic excitation through its successive relaxation stages and up to the final permanent amorphous lattice state. A complete physical model is formulated from the experimental data. (C) 2011 Optical Society of America