Wavefront sensor with Fresnel zone plates for use in an undergraduate laboratory
Principle of a Hartmann wavefront detector.
(a) Normalized radial distribution of the light intensity within the spots created by Fresnel zone plates with a given number of transparent zones (symbols) and by refractive lenses of the same aperture and focal length (solid lines). (b) The radius at half of the maximum intensity of the spot created by a zone plate as a function of the number of zones.
Experimental setup for wavefront measurements. Lenses and , wavefront-distorting element WD, and mask M.
Sample images from the wavefront sensor obtained with the masks shown. The scale is maintained between the images and the masks. (a) and (b) .
Geometry used in the reconstruction of the wavefront.
Typical deviations of a single measurement of a flat wavefront from the arithmetic mean of 20 measurements in intervals for the mask with focal lengths of (a) and (b) .
Sample distortions of the wavefront of a collimated laser beam propagating in a turbulent air flow induced by a soldering iron located beneath the beam. The focal lengths of the zone plates used are equal to (a) and (b) . (c) The wavefronts shown in (b) after subtracting a flat, tilted wavefront.
(a) The wavefront of a collimated beam reflected from a spherical mirror with an angle of incidence of . (b) The sections of the wavefront in the tangential and sagittal planes.
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