deletions | additions       diff --git a/Physical model.tex b/Physical model.tex  index e6c7f3b..7af31da 100644  --- a/Physical model.tex  +++ b/Physical model.tex 
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\gamma=\frac{2}{\delta}=2(\pi \sigma \mu_r \mu_0 \nu)^{\frac{1}{2}}  \label{eq:skinDepth}  \end{equation}  where $\sigma$ is the electrical conductivity of the medium, $\mu_r \mu_0$ its permeability, $\nu$ the frequency of the radiation and factor 2 is due the relation of $\delta$ with magnitude of the electrical field while $\gamma$ is related to the magnitude of the optical energy, equal to the square of the electrical field magnitude. Substituting $\sigma \approx$ 0.1 S.m$^{-1}$, $\mu_r \mu_0$ = 4 $\pi \times 10^{-7}$ H.m$^{-1}$ and $\nu$ = 3 10$^8$ / 532 10$^{-9}$ = 5.6 10$^{14}$ Hz, we find that $\gamma^{-1} \approx$ 35 $\mu m$: it means that about 63\% of the radiation energy is absorbed in the first 35 micrometers of the sample. We have validated experimentally this value by measuring the fraction of light which go through different thicknesses of the medium (respectively 0, 30, 50 and 100 $\mu$m) with a laser beam power measurement device (QE50LP-S-MB-D0 energy detector, Gentec, Qu\'ebec, QC, Canada). We found respective transmitted powers of 100\%, 88\%, 71\% 42\%, 28\%  and 57\%: 11\%:  an exponential fit indicated that $\gamma^{-1} \approx$ 50 $\mu m$ in our sample, which is in accordance with the theoretical value found previously.