Evaluation of Large Aberrations Using a Lateral-Shear Interferometer Having Variable Shear

Abstract

A variable shear lateral shearing interferometer consisting of two holographically produced crossed diffraction gratings is used to test nonrotationally symmetric wavefronts having aberrations greater than 100 wavelengths and slope variations of more than 400 wavelengths/diameter. Comparisons are made with results of Twyman-Green interferometric tests for wavefront aberrations of up to thirty wavelengths. The results indicate that small wavefront aberrations can be measured as accurately with the lateral-shear interferometer as with the Twyman-Green interferometer and that aberrations that cannot be measured at all with a Twyman-Green interferometer can be measured to about 1% accuracy or better.

Retrieving the axial position of fluorescent light emitting spots by shearing interferometry

“…In principle, one could obtain the wave front W according to the method of Rimmer and Wyant 23 by numerically integrating the difference V for two shears in orthogonal directions. This would also allow using the expansion in Ref.…”

Integrated diffractive shearing interferometry for adaptive wavefront sensing

“…Other implementations vary the rotation angle between a series of crossed gratings [20,21] or rely on rotation within Talbot self-imaging to alter the region of overlap [22]. Mechanical motion and tight tolerances associated with these techniques are not ideal for integrated devices.…”

Polynomial fit of interferograms

“…Because total wavefront Let us review the coefficient transformation approach. The following material is extracted from Rimmer and Wyant (1975). where N. is the digitized error.…”

“…Deleting test optics error (Parks, 1978) 1 2 2. Lateral shearing interferogram analysis (Rimmer and Wyant, 1975) 3. Ritchey-Common test (Shu, Parks and Shannon, 1981) 4.…”