MULTIPLE-BEAM LATERAL SHEAR INTERFEROMETRY FOR OPTICAL-TESTING

Lateral shear interferometry is used to obtain the lateral aberrations of a lens. The zeroth-order fringe in an interferogram obtained from a wedge-plate lateral shear interferometer, however, directly displays the lateral aberration curve of a test lens. Nevertheless, the intens ity distribution, is cosinusoidal. Multiple-beam interferometry result s in sharpened fringes; hence the multiple-beam wedge-plate shear inte rferometer displays the lateral aberration curve of a lens sharply, pr ovided the shear is small. For large shear, some new artifacts appear in the interferogram, which are also explained.