deletions | additions       diff --git a/The_maximum_displace.tex b/The_maximum_displace.tex  index a76d58f..ea5ee93 100644  --- a/The_maximum_displace.tex  +++ b/The_maximum_displace.tex 
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The maximum displacement was equal to 8 $\mu$m. This value is close to the sensitivity Even if Muthupillai et al. declared that displacements  of magnetic resonance elastography \cite{muthupillai1995magnetic} and ultrasound a few hundreds of nanometers should be sufficient to perform shear wave  elastography \cite{nightingale2002acoustic} about 10 \cite{7569924}, displacements of 5  to 20 $\mu$m. $\mu$m are usually required \cite{11937286}, which is slightly higher than the maximum displacement observed here (about 2 $\mu$m).  The maximum laser beam energy used in the chicken sample, 532 nm, 15 ns, 200 mJ for a 5-mm diameter beam, is about fifty times the maximumpermissible  exposure permissible  as given by the current  American National Standard Institute (Z136.1-2000) for skin \cite{ANSIZ1361}. It \cite{ANSIZ1361}, but  is also about five to ten times lower than the typical energy used for skin tatto removal \cite{8352621}. The linear dependence with laser energy means that shear waves of lower amplitude could be observed with more efficient displacement observation methods. This can be performed with better displacement tracking algorithms, and devices with an higher spatial resolution, like ultrasound probe of higher frequency or an optical coherence tomography probe. The laser have also the advantage to be 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, the probe used for laser can be made extremely small (smaller than 100 um diameter if required), especially if optical fibres are employed. There could be then an interest for endoscopy, by inducing displacement with a simple optic fibre which can be inserted in small intima or vessels. Additionally, the shear wave source does not emit electromagnetic noise (if the laser device is placed far from the region of interest), so it can be quite convenient for magnetic resonance elastography experiment which is 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}). 
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