A SCANNING INTERFEROMETER FOR WAVEFRONT ABERRATION MEASUREMENTS

The fundamental principles of operation and of the design of a new type of lateral shearing interferometer are described. This instrument has the advantage over existing devices that no computation is required in order to derive the wavefront, shape from the interferogram. Instead, the aberration is obtained directly by measurement of the variation of phase difference at the center of one of the component wavefronts as it is scanned across the other. The technique lends itself readily to automatic recording of wavefront aberration. © 1969 Optical Society of America.