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13 October 1986 A Shearing Interferometer For Astronomical Wavefront Sensing
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A wavefront sensor has been designed to measure wavefront aberrations occurring during astronomical observations with high spatial and temporal resolution. Results of laboratory experimentation are presented. The sensor consists of a grating lateral shear heterodyne interferometer using a solid-state detector array. It has high light efficiency and is a self-referencing interferometer, thus allowing the use of white-light extended astronomical sources for the measurements. The wavefront sensor employs a heterodyne technique and is insensitive to intensity variations across the pupil and detector nonuniformities. To obtain a wavefront map, two sets of orthogonal wavefront difference data from the lateral shear interferometer are required. Both sets are measured simultaneously using a single laminar grating to produce the sheared diffraction orders and a single solid-state detector array placed in a plane conjugate to the telescope pupil plane. The signal from the detector array is digitized and fed into a computer where the wavefront differences are calculated. From these differences a wavefront map on a square array of 24 by 24 points is obtained by filtering the data in the spatial frequency domain. The time required for the acquisition of a complete set of data for one wavefront map is 13.3 ms. A wavefront reconstruction may be done within several milliseconds by using fast algorithms and floating point processor hardware.
© (1986) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Klaus Freischlad and Chris L. Koliopoulos "A Shearing Interferometer For Astronomical Wavefront Sensing", Proc. SPIE 0627, Instrumentation in Astronomy VI, (13 October 1986);

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