  A method to create instructive, nonuniform aperture functions using spatial
frequency filtering is described. The diffraction from a single slit in the
Fresnel limit and the interference from a double slit in the Fraunhofer limit
are spatially filtered to create electric field distributions across an
aperture to produce apodization, inverse apodization or super-resolution, and
apertures with phase shifts across their widths. The diffraction effects from
these aperture functions are measured and calculated. The excellent agreement
between the experimental results and the calculated results makes the
experiment ideal for use in an advanced undergraduate or graduate optics
laboratory to illustrate experimentally several effects in Fourier optics.
