ABSTRACT
This chapter reviews experiments on the development of ultrashort acoustic solitons from intense picosecond strain wavepackets. It discusses generate millimeter-wide, nanometer-thick, supersonic disks with pressures as high as tens of kilobars. High-amplitude, bipolar wave-packets are injected by the impact of optical pulses from an amplified Ti-sapphire laser on a thin chromium film evaporated on the surface of the sapphire crystal. Under high-power excitation, the formation of a shock front occurs in a distance of less than 100 micrometers, the distance over which the strain pulse steepens by the velocity increase of the high-amplitude peak with respect to the low-amplitude front. The development of high-amplitude, ultrashort strain solitons opens up a variety of technological perspectives. High-pressure pulses of ultrashort time duration might therefore be applied to modify material properties with nanometer precision. For the problem of ultrashort strain packets in a crystalline lattice, it may well be worth the effort to consider a derivation that maintains the discrete character of the atomic lattice.
