© 2011 Thorlabs
100 Thorlabs Beam 4.0
3.5.6.2
Beam Alignment
Why Beam Alignment?
The Beam Profiler has a defined input aperture, so when moving it along the
translation stage's axis it must be ensured that the laser beam remains within the
aperture. Ideally, the beam centroid remains centered within the aperture during
movement of the beam profiler.
So prior to start M² measurement, the beam must be aligned parallel to the
movement axis of the stage and should hit the aperture in the center.
It is highly recommended to do the alignment procedure precisely in order to
obtain accurate measurement results.
Open the Initialize tab of M² measurement panel and additionally the 2D Projection
as shown below:
For beam alignment, the manual Translation Stage Control is used, while the
beam position is observed in the 2D Projection panel. For more convenience,
enable the Reference Position crosshair (set to sensor center) and enable the
centroid cross.
Preconditions
Prior to start beam alignment and measurement take care of these points:
- avoid reflections, interferences, ambient light
- check that entire laser beam is entering the Beam Profiler aperture
- warm up laser system 1 hour
- ensure that laser output is spatially and temporally stable
- set the camera beam profiler to Auto exposure mode.
- the camera must not enter saturation at any time!
Hints
It's helpful to enable the Reference Position, set to sensor center:
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