deletions | additions       diff --git a/Physical model.tex b/Physical model.tex  index 6da70c7..1e6ba70 100644  --- a/Physical model.tex  +++ b/Physical model.tex 
...
Let's examine now the physical phenomena involved in these experiments. The optical intensity, $I_0$, of the laser beam is defined as $I_0=\frac{1}{S}\frac{d E}{dt}$, where $S$ is the beam surface and $E$ is the beam energy. When emitted on the surface of a medium and in the absence of reflection, the laser beam is absorbed with an exponential decay as a function of the medium depth $z$: $I(z)=I_0 \exp(- \gamma z)$, where $\gamma$ is the absorption coefficient of the medium. We have experimentally estimated $\gamma$ by measuring the fraction of light that is able to penetrate \textcolor{red}{transmitted through  different thicknesses slices  of the medium (0, (with thicknesses of 0,  30, 50, and 100 $\mu$m) $\mu$m)}  with a laser beam energy-measurement device (QE50LP-S-MB-D0 energy detector, Gentec, Qu\'ebec, QC, Canada). We found respective transmitted powers of 100\%, 42\%, 28\%, and 11\%, with \textcolor{red}{which gives  $\gamma^{-1} \approx$ 40 $\mu m$ m$}  in our sample as indicated by an exponential fit.