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companies. Any rights not expressly granted herein are reserved. ATTENTION: Specifications and technical data are subject
to change without notice.
V.2.c.
Contact Mode
In Contact Mode the cantilever is not excited at its resonance frequency.
Only a DC voltage is applied to the dither piezo (normally on DAC1) and
correspondingly the DC voltage of the photo-detected signal (normally on
ADC1) is used to detect the topography.
Contrary to the non-contact mode the tip-fiber cavity is not set to the WP by
tuning DAC1 manually but by using ADC1 as the feedback input and defining
the working point WP as the setpoint.
1. Adjustment of the fiber-cantilever cavity length:
Execute a dither spectroscopy (photo-detector signal (normally on ADC1)
vs. DC dither voltage (normally on DAC1)) to check the interferometric
signal. To do so, choose the 'Spectroscopy' and the 'Spectroscopy View' tab
with the following settings:
Start:
0V
End :
4V (@RT); 10V (@LT)
Data Points:
1000
Data Point Avg. Time: 2ms
Delay per Data Point: 0ms
Start the spectroscopy.
The ‘
Spectroscopy View
’ should look similar to the Figure 18 below.
The working point WP (point of highest sensitivity where signal depends
linearly on the cavity length between fiber end and cantilever) is located at
the midpoint between minimum and maximum of the interference signal.
Содержание attoAFM I
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