Digital resolution enhancement in surface plasmon microscopy

The use of photonic crystal and negative refractive index materials is known to improve the resolution of optical microscopy and lithography devices down to the 80 nm level. Here we demonstrate that utilization of well-known digital image recovery techniques allows us to further improve the resolution of optical microscopy down to the 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 a 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.