A review of optical near-fields in particle/tip-assisted laser nanofabrication

Abstract

Nanofabrication by using lasers with a spatial resolution beyond the optical diffraction limit is a challenging task. One of the solutions is to use near-field techniques, in which evanescent waves dominate over free waves in the vicinity of scattering objects and sub-diffraction-limited focus (as small as ∼10 nm) can be achieved. Theoretical modelling of near-field phenomena is extremely important for the understanding of these near-field techniques, especially for some cases where it is not possible to directly measure the near-fields. In this article, a brief review of the existing near-field laser nanofabrication techniques is given. Different theoretical methods for the computation of optical near-fields, including both analytical and numerical methods, are then presented. The optical near-field distributions of different micro/nano-systems (isolated particles, aggregated particles, particles on the substrate, particles in liquid, and the tip-sample system) are then reviewed in detail within the framework of laser nanofabrication.