| 摘要 |
A method for analyzing a wavefront of light finds application in the control of mirror segments in a segmented mirror array. A shearing interferometer is used to combine a beam of light from a reference mirror segment with beams from individual controllable segments, creating detectable interference. The path length through the interferometer is modulated in time in a focusing region, causing the wavefronts of the beams to fluctuate in curvature. Magnification of one of the beams relative to the other gives it a less severe curvature in the region where the beams overlap. Orientation differences between compared segments can be found at a point of interference detection by comparing, with regard to the modulation cycle, the detection time of the wavefront in question and the detection time of the reference wavefront. By shearing the light from a number of segments with different parts of the reference wavefront, orientation differences for a number of segments can be detected simultaneously. Actuators on the controllable segments corresponding to the detectors in the interference region can be used to adjust the segments, reducing the orientation differences.
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