Instruction manual

TappingMode AFM
Preparation Prior to Imaging
108 MultiMode SPM Instruction Manual Rev. B
Figure 7.2d Voltage meters on the MultiMode base reveal a great deal about the amplitude and alignment of the
TappingMode laser signal on a tuned tip operating at its resonant frequency.
Small laser signal amplitude
yields low output voltage.
Vertical voltage difference
high because laser signal
falls on bottom half of
photodetector only.
Well centered laser
beam yields a vertical
voltage difference of zero.
Larger laser signal amplitude
yields higher output voltage.
Sum voltage low due to
misalignment of laser on
cantilever or laser on
photodetector.
Sum voltage higher due to
stronger laser signal. All of
beam falls on photodetector.
RMS VERT
SUM
0.06
9.91
1.2
RMS VERT
SUM
0.28
0.00
3.8