Primes HP-MSM-HB, Оригинальное руководство пользователя

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128
Revision 00 EN - 01/2021
HP-MSM-HB
35,0(6
24.4.6 Caustic (menu Presentation > Caustic)
The results of the caustic measurement can be displayed by means of the menu item
Presentation >
Caustic
. On the left Fig. 24.17 on page 128 shows the measured beam parameter either on the basis of
the 86%-radii or the 2. moment method evaluation according to ISO 11146. In the middle of the picture the
graphic shows the caustic profile. The beam radii are depicted on the beam spread direction. On the right is
a false color presentation of the measurement plane selected with the mouse shown together with numerical
results of this corresponding plane.
Fig. 24.17: Dialogue window Caustic
The red line depicts a compensation curve according to the calculated fits which can be displayed via the
check box
Fit
in the 2D presentation.
Compensating curve
In order to evaluate the caustic, a hyperbolic compensating curve (ISO 11146) is adapted to the measur-
ing values. This compensating curve describes the propagation of an ideal laser beam mathematically. The
development of the compensating curve is theoretically determined by means of the following parameters:
• Standardized beam quality factor M² or respectively beam propagation ratio K
• z-position
• focus radius
• Rayleigh length
Standardized beam quality factor M² (or respectively the beam propagation ratio K= )
The normed beam quality factor describes how well the affected laser beam can be focused in relation to the
dominant mode. The basic mode represents the theoretically best possible beam and has a beam quality
factor M² of 1. All other beams have higher M² values.