Consolidate fig:afm-schematic and fig:piezo-schematic into one figure.

Also cite binnig86 (AFM with STM sensor) and meyer88 (AFM with optical
lever) when introducing the AFM.

diff --git a/src/apparatus/afm.tex b/src/apparatus/afm.tex
index ef6babbd1895942d933ac3edddc9691ad29ec73c..234bf989c090b309c3fa5f85ab5e40aa8e10815f 100644 (file)
--- a/src/apparatus/afm.tex
+++ b/src/apparatus/afm.tex
@@ -10,21 +10,12 @@ transitions in DNA\citep{florin95,rief99} and
 polysaccharides\citep{rief97a}.
 
 An AFM\index{AFM} uses a sharp tip integrated at the end of a
-cantilever to interact with the sample.  Cantilever bending is
-measured by a laser reflected off the cantilever and incident on a
-position sensitive photodetector (\cref{fig:afm-schematic}).  When the
-bending force constant of the cantilever is known\citep{levy02}, the
-force applied to the sample can be calculated using Hooke's law
-(\cref{eq:sawsim:hooke}).
-
-\begin{figure}
-  \asyinclude{figures/schematic/afm}%
-  \caption{Operating principle for an Atomic Force
-    Microscope\index{AFM}.  A sharp tip integrated at the end of a
-    cantilever interacts with the sample.  Cantilever bending is
-    measured by a laser reflected off the cantilever and incident on a
-    position sensitive photodetector.\label{fig:afm-schematic}}
-\end{figure}
+cantilever to interact with the sample\cite{binnig86}.  Cantilever
+bending is measured by a laser reflected off the cantilever and
+incident on a position sensitive photodetector\cite{meyer88}
+(\cref{fig:afm-schematic}).  When the bending force constant of the
+cantilever is known\citep{levy02}, the force applied to the sample can
+be calculated using Hooke's law (\cref{eq:sawsim:hooke}).
 
 The substrate is mounted on a three dimensional piezoelectric actuator
 so that the tip may be positioned on the surface with sub-nanometer
@@ -34,19 +25,31 @@ range of TODO in the horizontal directions and a range of TODO in the
 vertical (\cref{fig:piezo-schematic}).
 
 \begin{figure}
-  \asyinclude{figures/schematic/piezo}%
-  \caption{Schematic of a tubular piezoelectric actuator.  In our AFM,
-    the substrate is mounted on the top end of the tube, and the
-    bottom end is fixed to the microscope body.  This allows the piezo
-    to control the relative position between the substrate and the AFM
-    cantilever.  The electrodes are placed so radial electric fields
-    can be easily generated.  These radial fields will cause the piezo
-    to expand or contract axially.  The $z$ voltage causes the tube to
-    expand and contract uniformly in the axial direction.  The $x$ and
-    $y$ voltages cause expansion on one side of the tube, and
-    contraction (because of the reversed polarity) on the other side
-    of the tube.  This tilts the tube, shifting the sample
-    horizontally.\label{fig:piezo-schematic}}
+  \begin{center}
+    \subfloat[][]{\label{fig:afm-schematic}
+      \asyinclude{figures/schematic/afm}}
+    \hspace{.25in}%
+    \subfloat[][]{\label{fig:piezo-schematic}
+      \asyinclude{figures/schematic/piezo}}
+    \caption{\subref{fig:afm-schematic} Operating principle for an
+      Atomic Force Microscope\index{AFM}.  A sharp tip integrated at
+      the end of a cantilever interacts with the sample.  Cantilever
+      bending is measured by a laser reflected off the cantilever and
+      incident on a position sensitive photodetector.
+      \subref{fig:piezo-schematic} Schematic of a tubular
+      piezoelectric actuator.  In our AFM, the substrate is mounted on
+      the top end of the tube, and the bottom end is fixed to the
+      microscope body.  This allows the piezo to control the relative
+      position between the substrate and the AFM cantilever.  The
+      electrodes are placed so radial electric fields can be easily
+      generated.  These radial fields will cause the piezo to expand
+      or contract axially.  The $z$ voltage causes the tube to expand
+      and contract uniformly in the axial direction.  The $x$ and $y$
+      voltages cause expansion on one side of the tube, and
+      contraction (because of the reversed polarity) on the other side
+      of the tube.  This tilts the tube, shifting the sample
+      horizontally.\label{fig:afm-schematic-and-piezo}}
+  \end{center}
 \end{figure}
 
 % really, AFM can do this ;)