deletions | additions       diff --git a/The_maximum_displace.tex b/The_maximum_displace.tex  index e43b9ed..e237d89 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 of magnetic resonance elastography \cite{muthupillai1995magnetic} and ultrasound elastography \cite{nightingale2002acoustic} about 10 to 20 $\mu$m. The laser beam energy used in the chicken sample, estimated at 10 mJ/mm$^2$, was about a ten times higher than the american \textit{Food and Drug Administration} standard maximum. 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 more efficient displacement tracking algorithms or devices with a better spatial resolution, like ultrasound probe of higher frequency or optical coherence tomography probe.  For shear wave elastography, a laser probe could control easily  the sources of displacement currently in use (surface vibrator or transducers using acoustic radiation force) are rather considered as adequate for elastography technique, so there is no strong need shear wave shape (focusing capabilities  for alternatives right now. The laser is more expensive than simple vibrator and involves higher risks example, see  for patients example \cite{noroy1993laser}),  with high-power laser. an high speed repetition rate.  However, there could be some particular applications where current probes prove unsuitable. A laser probe could control easily the shear wave shape (focusing capabilities for example, see for example \cite{noroy1993laser}), with an high speed repetition rate. 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\cite{li2011elastic},\cite{li2012noncontact}  or cornea \cite{li2011elastic},\cite{li2012noncontact},  \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 expensive non-magnetic ultrasound probes - even if this price needs to be balanced with the one of a laser probe. This study presented observation of elastic shear waves generated in soft tissues using a laser beam. The involved phenomenon was investigated. Experiments in chicken breast sample showed the feasibility of an elastography method using a laser beam as a shear wave source.