  The laser ultrasonics technique perfectly fits the needs for non-contact,
non-invasive, non-destructive mechanical probing of samples of mm to nm sizes.
This technique is however limited to the excitation of low-amplitude strains,
below the threshold for optical damage of the sample. In the context of strain
engineering of materials, alternative optical techniques enabling the
excitation of high amplitude strains in a non-destructive optical regime are
seeking. We introduce here a non-destructive method for laser-shock wave
generation based on additive superposition of multiple laser-excited strain
waves. This technique enables strain generation up to mechanical failure of a
sample at pump laser fluences below optical ablation or melting thresholds. We
demonstrate the ability to generate nonlinear surface acoustic waves (SAWs) in
Nb:SrTiO$_3$ substrates, at typically 1 kHz repetition rate, with associated
strains in the percent range and pressures close to 100 kbars. This study paves
the way for the investigation of a host of high-strength SAW-induced phenomena,
including phase transitions in conventional and quantum materials, plasticity
and a myriad of material failure modes, chemistry and other effects in bulk
samples, thin layers, or two-dimensional materials.

Materials Science;Optics