\section{Introduction}
-Cantilevers are used inside atomic force microscope which provides high
+Cantilevers are used inside atomic force microscope (AFM) which provides high
resolution images of surfaces. Several technics have been used to measure the
displacement of cantilevers in litterature. For example, it is possible to
determine accurately the deflection with different mechanisms.
then a estimation method is required to determine the displacement of each
cantilever. In~\cite{AFMCSEM11}, the authors have used an algorithm based on
spline to estimate the cantilevers' positions.
-%%RAPH : ce qui est génant c'est qu'ils ne parlent pas de spline dans ce papier...
+
The overall process gives
accurate results but all the computation are performed on a standard computer
using labview. Consequently, the main drawback of this implementation is that
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.
-%%RAPH : est ce qu'on pique une image? génant ou non?
-The system build by authors of~\cite{AFMCSEM11} has been developped based on a
-Linnick interferomter~\cite{Sinclair:05}. A laser beam 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 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.
+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 beam 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 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}
%% image tirée des expériences.
