THORLABS WFS20-14AR, Руководство по эксплуатации

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Wavefront Sensor
Positive RoC distances represent divergent spherical wavefronts where the point source is loc-
ated in front of the Wavefront Sensor reference plane, whereas negative values indicate a con-
vergent spherical wavefront with a virtual focal point that lies behind the Wavefront Sensor ref-
erence plane. The higher the absolute RoC value, the flatter the corresponding wavefront and
the higher the parallelism of the beam.
In the case of a planar wave front, the Z5 term theoretically should be 0, and the RoC infinite.
As a result, the wavefront sensor will not be able to measure large RoC values accurately. In
order .to indicate the reduced accuracy of of RoC v
played in the following format:
RMS Variations
Since the Zernike modes are normalized to unity variance, all Zernike coefficients of a particu-
lar order can be summed and expressed as total RMS variation of this Zernike order. The num-
ber of Zernike orders, defined in the
Zernike Fit Setup panel, will determine the number of
output appropriate RMS variation results.
Zernike Modes
The coefficients of the Zernike modes which are determined by a least square fit to the meas-
ured wavefront are displayed either in microns or waves. The mode number is followed by the
order and frequency number of the mode in brackets.
Fit Error
The fit error describes the difference between the measured and the reconstructed wavefront.
A lower value indicates a better fit. Usually, a Zernike fit that uses more modes will reduce the
fit error.
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