THORLABS WFS20-14AR, Руководство по эксплуатации

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5 Operating Instruction
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Please go to the Wavefront Sensor Setup
à
Pupil Definition, switch off both options and define
the pupil diameter and position manually. Please consider the hints given in chapter Pupil
Definitions Setup .
Adaption to previously measured spot centroids
If centroid adaption is off ( ) the software defines a rigid grid of spot interroga-
tion windows based on the spot reference positions. Since the actual detected spot centroids
match their reference positions only in case of exactly orthogonal incidence of a pure plane
wavefront, it is likely that some spots of an arbitrary measured wavefront will not fall into the ref-
erence grid. The following error occurs:
Therefore, it is highly recommended to enable option 'Adapt Centroids' ( ). In this
case, the software checks if the spot centroid positions measured in Normal Mode are suitable
to define a grid of calculation windows that can capture all spots. The grid is flexible with re-
spect to window size and offset position in both x and y direction. This flexibility allows adaption
of tilted and spherical wavefronts of a moderate amplitude.
If the above error message occurs, the input wavefront is so excessively deformed that it can-
not be measured in High-Speed Mode.
In High-Speed mode, the status window will display a warning that there is a risk of incorrect
measurement results due to restricted error detection capabilities:
Auto Exposure in High-Speed Mode
It is recommended that Auto Exposure be enabled in High-Speed Mode. This way, a sensor
saturation can be avoided. Overexposure or underexposure (Warnings "Power too high" or
"Power too low" in the status window) lead to wavefront measurement errors.
Disable the auto exposure feature in High-Speed Mode only in case of a sufficient and nearly
constant input power level.
Another detectable error in high speed mode is the violation of the spot windows by the detec-
ted centroids:
Note
If this warning occurs, the wavefront measurement is most likely affected by spots that are trun-
cated by their detection windows.
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