PRIMES
BeamMonitor BM+ with LDS 2.98
51
Revision 01/2018 EN
11.2.8
Symmetry Check
This display menu checks the rotational symmetry of the power density distribution of a laser beam. It can,
for instance in connection with the monitor operation, be used for the alignment of laser resonators.
In the following, the figures Fig. 11.21 and Fig. 11.22 show two examples for the possible results of a sym-
metry check at an elliptic beam.
Fig. 11.20: Power density distribution of an elliptic beam
Together with the
Symmetry check
the power density distribution of an elliptic beam as displayed in Fig.
11.20 comes to the following results:
Fig. 11.21: Presentation in Cartesian coordinates
The abscissa in Fig. 11.21 shows the angle and the ordinate of the beam radius with the intersection lines
at different powers between 86 % and 10 % of the total power.
On the screen the curves appear in different colors. The radius is indicated in pixel coordinates. The mini-
mum as well as the maximum of the radius values can be chosen. On the right side the standard deviation
of the different radius values is indicated. These values give detailed information on the symmetry of the
beam distribution.
Well aligned resonators reach standard deviations in the range of 3 % to 5 %. Partially, values in a 1 % and
2 % range are possible.
