Scanning near-field photolithography--surface photochemistry with nanoscale spatial resolution.

This tutorial review describes recent advances that have challenged the traditional view that the Rayleigh limit, of approximately lambda/2, represents the ultimate resolution accessible using optical methods. Near-field optical methods offer a powerful capability for optical measurement and manipulation of materials. Using a scanning near-field optical microscope coupled to a UV laser it is possible to create photopatterned molecular structures with dimensions nearly 15 times smaller than the Rayleigh limit. Near-field methods offer the possibility for selective initiation of surface chemical transformations with exquisite spatial resolution, bringing the prospect of unifying top-down and bottom-up nanofabrication into view.