Abbreviated Instructions for the MultiMode AFM
Rev. F
Scanning Probe Microscope Training Notebook
33
15.6 Align Laser and Tip-Sample Approach (2 Methods)
1. Magnifier Method for Aligning Laser and Tip-Sample:
a. Focus on the side-view of the cantilever with the magnifier. If you are having trouble
finding the cantilever, try searching for the red light of the laser and focus on that. Use
the “paper method” described below for positioning the laser spot on the cantilever:
b. Move laser until it is at the front edge of the cantilever substrate. Move laser just off the
front edge and move laterally along the edge looking for the reflection of the laser spot
from the cantilever onto the paper. Center the laser on the cantilever at its end.
c. Keeping the optical head level, focus on the laser reflection of the cantilever and sample
to bring the cantilever close to the sample. Use screws at the base of the optical head
(front and left) to position the cantilever over the area of interest on the sample.
2. Optical Viewing Microscope Method for Aligning Laser and Tip-Sample
a. Place the microscope on the optical microscope positioning stage.
b. Turn on the monitor and the light source.
c. Focus on the cantilever (zoom out, if using optical microscope equipped with zoom).
Use the base screws on the stage of the optical microscope to center the cantilever in the
field of view. Lower the focus of the optical microscope to the sample surface. You will
still see an out of focus “shadow” of the cantilever in the field of view. Keep the optical
head level while lowering the cantilever until it is almost in the same plane of focus -
keep the shadow of the cantilever in the field of view at all times. It is helpful to go up
and check the focus on the cantilever from time to time to see how close it is to the
sample surface.
d. Once the cantilever is close to the sample surface, adjust the laser so that it is positioned
over the cantilever. Use the two screws at the top of the optical head to move the red
laser spot onto the cantilever. You may need to change the field of view of the optical
microscope initially to find the laser spot.
e. Next use the “paper method” (as described under Magnifier Method) to fine position the
laser spot on the cantilever. Use the two screws at the base of the optical head (front and
left) to position the cantilever over the area of interest on the sample. As the stepper
motor moves during engagement, the cantilever will shift towards the back of the
microscope (unless you are using a Vertical Engage Scanner). This means that you
should place the cantilever in front of (below on the monitor) the area where you want to
engage.