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For elastography measurements, Muthupillai et al. assumed that a displacement of a few hundreds of nanometers should be sufficient to perform shear wave elastography \cite{7569924}. However, displacements of 5 to 20 $\mu$m are the order of the micrometer is  usually required, which isslightly  higher than themaximum  displacement observed here (about 2 $\mu$m at a energy of 10 mJ in thermoelastic regime and about the same order of magnitude at a energy of 200 mJ  in the chicken breast sample). ablative regime.  The minimum energy of the laser (532 nm, 10 ns, 80 10  mJ, 5 mm diameter) used in our experiments to get a shear wave is about twenty 2.5  times higher than above  the maximum exposure permissible as given by the current American National Standard Institute (Z136.1-2000) for skin \cite{ANSIZ1361}, a value which is also used in typical photoacoustic imaging experiments \cite{Ku_2005}. This value is also about fifty a few hundred  times lower than the typical energy used for skin tatoo removal \cite{8352621}. There are different ways to obtain measurable displacements with a lower laser energy: using more efficient speckle-tracking algorithm, decrease the ultrasound acquisition frame-rate, or averaging over multiple experiments. The laser also has the advantage of being non-contact and totally remote. For example, Li et al. have proposed to induce surface acoustic waves by laser to measure elastic properties of biological thin layers like skin or cornea \cite{li2011elastic}, \cite{li2014laser}. Moreover, a laser probe can be made extremely small (smaller than 100 $\mu$m diameter if required), especially if optical fibres are employed, for example for insertion in small vessels. Additionally, the shear wave source emits very weak electromagnetic noise (apart from the laser device itself), so it can be quite convenient for magnetic resonance elastography measurements, which are currently using external drivers or non-magnetic ultrasound probes. Moreover, the laser probe could help to shape precisely the shear wave shape, with focusing capabilities for example (see for example \cite{noroy1993laser}).