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:SrTiO3 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.
@article{arxiv.2209.13897,
title = {Additive Laser Excitation of Giant Nonlinear Surface Acoustic Wave Pulses},
author = {Jude Deschamps and Yun Kai and Jet Lem and Ievgeniia Chaban and Alexey Lomonosov and Abdelmadjid Anane and Steven E. Kooi and Keith A. Nelson and Thomas Pezeril},
journal= {arXiv preprint arXiv:2209.13897},
year = {2023}
}