Near-field electromagnetic devices having an opaque metallic screen with a
fractal iterate aperture are provided. More specifically, the aperture is
obtained by application of a self-similar replacement rule to an initial
shape two or more times. Alternatively, the aperture can be obtained by
application of a self-similar replacement rule one or more times to an
initial C-shape. Such apertures tend to have multiple transmission
resonances due to their multiple length scales. Fractal iterate apertures
can provide enhanced transmission and improved spatial resolution
simultaneously. Enormous improvement in transmission efficiency is
possible. In one example, a checkerboard fractal iterate aperture
provides 10.sup.11 more intensity gain than a square aperture having the
same spatial resolution. Efficient transmission for fractal iterate
apertures having spatial resolution of .lamda./20 is also shown. The
effect of screen thickness and composition can be included in detailed
designs, but do not alter the basic advantages of improved transmission
and spatial resolution provided by the invention.