Speaker
Description
Pulsed lasers are routinely used to excite and detect acoustic waves over a broad frequency range, from MHz to THz. Laser ultrasonics enables non-contact, non-invasive, and non-destructive mechanical probing of samples with dimensions ranging from millimetres to nanometres. Although established for decades, the technique is constrained by optical damage thresholds, which typically limit the achievable acoustic pressures to values well below the gigapascal range. Higher pressures, sufficient to generate shock waves, can be reached at the expense of irreversible sample damage. Such experiments therefore require single-shot measurements, often with limited reproducibility and low signal-to-noise ratios. These limitations motivate the development of alternative optical approaches capable of generating large-amplitude strain pulses without damaging the sample, opening new perspectives for strain engineering of materials.
In this talk, I will present a novel methodology for generating non-destructive shock waves at high repetition rates, with amplitudes limited only by the mechanical strength of the sample [1]. Through selected case studies, I will show how this approach can be combined with time-domain Brillouin scattering, a time-resolved optical technique based on the generation and detection of GHz acoustic waves, to probe the mechanical response induced by the passage of these shock waves. This methodology opens new opportunities for systematic investigations of subtle strain-induced phenomena in strain-sensitive correlated materials.
[1] J. Deschamps, Y. Kai, J. Lem, I. Chaban, A. Lomonosov, A. Anane, S. Kooi, K. Nelson, T. Pezeril, Additive laser excitation of giant nonlinear surface acoustic wave pulses, Phys. Rev. Appl. 20, 044044 (2023).
| Type of presence | Presence online |
|---|