Figure 2.2B Early Contact Afm Which Allowed Imaging Non-Conductive Samples; Figure 2.2C Optical Lever For Monitoring Tip Movement - Veeco 004-210-000 Instruction Manual

an electronic image. The main disadvantage of this method was difficulty in aligning the contacting
tip's cantilever and the STM tip directly above it.

Figure 2.2b Early Contact AFM which allowed Imaging Non-conductive Samples

AFM tip
Preceding the first SPMs, some profilometers had relied upon optical methods to monitor the rise
and fall of a sharp stylus over sample surfaces. This approach offered good sensitivity by reflecting
a laser beam off the end of the stylus and into a photodetector to obtain an "optical lever" capable of
detecting even the smallest movements (see
A related method utilized interference to detect shifts in interference fringes.
Laser beam movement is monitored over two axes: vertically and horizontally. As the tip traces
various surface features, its upward and downward movement shifts the beam between upper and
lower photodiode components, creating voltage differences which are electronically rendered into
height information. Lateral movements of the beam are also monitored, corresponding to frictional
phenomena on the surface.
Rev. B
STM tip
Sample

Figure 2.2c Optical Lever for Monitoring Tip Movement

Photodetector
MultiMode SPM Instruction Manual
SPM Fundamentals for the MultiMode
Control Mechanisms and Feedback
Flexible cantilever
Figure 2.2c). This approach was then applied to SPMs.
Laser
Cantilever and tip
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