+In order to develop simple, cost effective and user-friendly cantilever arrays,
+authors of ~\cite{AFMCSEM11} have developped a system based of
+interferometry. In opposition to other optical based systems, using a laser beam
+deflection scheme and sentitive to the angular displacement of the cantilever,
+interferometry is sensitive to the optical path difference induced by the
+vertical displacement of the cantilever.
+
+The system build by authors of~\cite{AFMCSEM11} has been developped based on a
+Linnick interferomter~\cite{Sinclair:05}. It is illustrated in
+Figure~\ref{fig:AFM}. A laser diode is first split (by the splitter) into a
+reference beam and a sample beam that reachs the cantilever array. In order to
+be able to move the cantilever array, it is mounted on a translation and
+rotational hexapod stage with five degrees of freedom. The optical system is
+also fixed to the stage. Thus, the cantilever array is centered in the optical
+system which can be adjusted accurately. The beam illuminates the array by a
+microscope objective and the light reflects on the cantilevers. Likewise the
+reference beam reflects on a movable mirror. A CMOS camera chip records the
+reference and sample beams which are recombined in the beam splitter and the
+interferogram. At the beginning of each experiment, the movable mirror is
+fitted manually in order to align the interferometric fringes approximately
+parallel to the cantilevers. When cantilevers move due to the surface, the
+bending of cantilevers produce movements in the fringes that can be detected
+with the CMOS camera. Finally the fringes need to be
+analyzed. In~\cite{AFMCSEM11}, the authors used a LabView program to compute the
+cantilevers' movements from the fringes.
+
+\begin{figure}
+\begin{center}
+\includegraphics[width=\columnwidth]{AFM}
+\end{center}
+\caption{schema of the AFM}
+\label{fig:AFM}
+\end{figure}
+
+
