30
distance to the mirror from the camera but if we assume > 0.1 m distance then the
angular noise is < 1 μrad. In reality we see air turbulence and temperature drifts
lead to beam noise of more than this but we have locked with targets sizes of 10
μm and distances of 2 m so angular tolerances of <5 μrad.
What is the beam pointing which results from one step on a Picomotor?
A typical Picomotor step is <30 nm and mirror mount lever arm is ~50 mm so the
angular change with one step is less than 0.6 μrad.
Do we have to set up the 2 cameras after the two mirror mounts?
It is common for set-ups to have CAM1 directly behind MM2. This is not a
configuration we recommend because in this set up any movement of MM2 will
have no effect on the beam going to CAM1 and so there are multiple solutions
for the beam to hit the two cameras.
What should I do if I don’t see the beam on one (or both) Camera(s)?
Make sure both cameras are connected to the Model 8783 Controller. If so, try
lowering the Camera Pixel Clock setting to 10-20. If the problem persists, close
the GuideStar II application and open the MicroEye Camera Manager program.
Ensure that both cameras show up in the Camera List with the appropriate
Camera ID.
How do I swap camera ID’s:
Close the GuideStar II application and start the uEye Camera Manager. Both
cameras should appear in the list. Select one, then click “Camera Information”
and change its camera ID from 1 to 2 or from 2 to 1. Click “OK”, and then do the
same for the other camera. Close the uEye Camera Manager and restart the
GuideStar II application. If the System Set-up window does not open after re-
starting, click the System set-up button. Perform the camera check again.
None (or only one) of my Picomotors is moving either manually or
automatically. How can I fix this?
First make sure that the each Picomotor is connected to its appropriate port on the
Model 8783 GuideStar II Controller front panel. If so, it has been found that the
best course of action is to un-install the GuideStar II application and all associated
programs/files, then re-install. This will usually do the trick.
What is the advantage using CMOS camera instead of PSD?
The position measurement performances are similar but the camera gives
information on beam size and shape as well. We use that information to make
sure the stabilization routine is “smart” and does not have any unnecessary or
dangerous beam steering.
