  The use of photonic crystal and negative refractive index materials is known
to improve resolution of optical microscopy and lithography devices down to 80
nm level. Here we demonstrate that utilization of well-known digital image
recovery techniques allows us to further improve resolution of optical
microscope down to 30 nm level. Our microscope is based on a flat dielectric
mirror deposited onto an array of nanoholes in thin gold film. This
two-dimensional photonic crystal mirror may have either positive or negative
effective refractive index as perceived by surface plasmon polartions in the
visible frequency range. The optical images formed by the mirror are enhanced
using simple digital filters.
