Portable Optical Tweezers Kit
Chapter 7: Experiments
Rev B, July 8, 2019
Page 65
Focus Level Settings
Set the laser focus so that you see the sample beads clearly and sharply. By moving the
laser spot onto a bead using the servomotors and levers on the K-cube controllers, you
can trap a bead and move it to another location. If you are able to capture one of the beads,
you have found the correct focus level.
Please note that reflections of the laser may occur. In the camera image, these will appear
with varying diameter (small spots or larger shapes). These are not a sign of bad
adjustment and can be ignored.
At this point, if the trapped beads move out of the focal plane, it indicates that the focal
planes of the laser and camera system are not aligned. See Section 6.5, above, for details.
7.3. Arranging the Silica Beads
In order to get to know the optical tweezers better, try next to move as many beads as
possible to one location using the K-cube controllers as shown in Figure 50. These
controllers allow you to set different speeds. You can use this to your advantage when
releasing the beads.
If you experience lagging of the camera image, try to reduce the frame rate in the camera
settings.
Hint
With older or slightly dried samples, one can observe that some beads no longer move,
but instead "stick" in place.
Summary of Contents for EDU-OT2
Page 1: ...EDU OT2 EDU OT2 M Portable Optical Tweezers User Guide...
Page 91: ......
Page 92: ...www thorlabs com...
