THORLABS M2MS, Operating Manual

Page: 90 / 167

BP209 Series 7 Operation Instructions
Page 88
21424-D02
7.2.7.1 Beam Alignment
Why Beam Alignment?
The Beam Profiler has a defined input aperture, so when moving the translation stage 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 stage - this is a precondition for correct
beam quality measurements.
All internal parts of the M2MS Measurement System are factory aligned. A beam entering the
M2MS exactly parallel to the stage movement direction will remain centered to the Beam
Profiler aperture during stage movement. In other words, the beam alignment is dependent only
on the position of the light source. In the common case, the light source is a device with open
beam output. In order to direct the beam under test into the M2MS, a combination of two
adjustable mirrors is required, Thorlabs offers a variety of such items.
The beam alignment is executed in 3 steps, guided by a software wizard:
1. Coarse Alignment : Determine the correct location of the Laser Under Test output aperture
by means of an auxiliary laser (included).
2. Beam Alignment of the Laser Under Test for minimum beam displacement and pointing
angle without focusing lens.
3. Alignment of the Focusing Lens for minimum beam displacement and pointing angle.
89
92
96