© 2011 Thorlabs
85Operating the Beam Profiler
3.5.2
M² Application recommendations
This section describes exemplary needs which are useful for some applications.
The BC106 Beam Profiler is delivered with a SM1BC adapter which allows to mount
1 inch threaded extensions to the Beam Profiler. The following examples give an
idea how to realize special needs and how to personalize the Beam Profiler setup.
Using anti-reflection (AR) coated filters
In some cases it can be advantageous to use AR coated filters instead of the
uncoated filters on the Filter wheel . These uncoated filters might allow reflections
from the camera CCD sensor to the filter and back to the sensor. Under certain
circumstances (like not perfectly aligned optical elements in the optical path) these
reflection tend to walk over the sensor while driving the camera over the translation
stage.
This effect can be avoided by using AR coated filters - reflected light from the CCD
sensor is not reflected from the filter surfaces. Stackable AR coated filters can be
found on our website www.thorlabs.com.
Suppressing ambient light
In a M
2
measurement the beam width on the CCD sensor varies. At constant laser
power the beam intensity increases when approaching the beam waist. In this case,
the exposure time is adapted in order to avoid saturation of the camera.
Though the Ambient Light Correction is able to eliminate influence of ambient
light, particularly at extended exposure time, it is recommended to shield the BC106
input aperture from ambient light, for example using SM1Lxx lens tubes with SM1BC
adapter. Lens tubes can be found on our website www.thorlabs.com.
Attention
Make sure that a mounted to the BC106 camera beam profiler lens tube
won't collide with other parts of the optical setup!
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