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THORLABS WFS Series User Manual

THORLABS WFS Series
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© 2007-2012 Thorlabs GmbH
26 WFS Series
The image is scanned for detectable spots generated by the microlenses and their
positions are compared to reference positions. The user select an internal or an user
reference table of spot positions.
Spot deviations are calculated and afterwards integrated in order to get a wavefront
array which is displayed in a 3D diagram. All valid spot deviations within the defined
pupil region and the desired number of Zernike orders / modes are input data to the
Zernike fit that fits the measured wavefront using well-known Zernike functions.
Output data are Zernike coefficients which are displayed numerically and within a
bar graph panel. All or a few selected Zernike modes are used for the wavefront
reconstruction. Also the difference between measured and fitted wavefront data is
available.
3.1
Shack-Hartmann Functional Principle
The WFS series Wavefront Sensor consists basically of a CCD/CMOS camera with
a microlens array mounted in a defined distance in front of its sensor chip. Each
microlens generates a spot onto the sensor whereas the spot centroid position
depends on the wavefront gradient in front of the lens area.
Each microlens of the lenslet array collects the light falling onto its aperture and
generates a single spot on the detector plane (CCD/CMOS camera) that is situated
a focal length behind the lenslets. The spot positions are straight behind the lenses
only in case the launched wavefront is plane and parallel to the plane of the lenslets.
We call these the Reference Spot Positions or reference spotfield.
In the common case however, the current spot positions will be deviated in X and Y
direction, that is, every spot lies away from the optical axis z of its associated
microlens, separated by an angle

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THORLABS WFS Series Specifications

General IconGeneral
BrandTHORLABS
ModelWFS Series
CategoryAccessories
LanguageEnglish