Two-photon polymerisation for three-dimensional micro-fabrication

This article presents an overview of the recent work related to the fabrication of three-dimensional (3D) micro-structures and photonic devices by means of the two-photon polymerisation (2PP) technology. The principle of the 2PP technique and the method for micro-fabrication are introduced in this article. The solidified size of a micro-structure formed during the photo-polymerisation process can be controlled by adjusting optical fabrication parameters; the minimum size can be as small as 150 nm. The influence of photo-initiators and material properties of a resin are discussed. Recent progress related to the development of initiators and resins for 2PP is briefly introduced. Chemical processes, preparation procedures and post-processing of the common resins (including commercialised and customer-made ones) are summarised in tables. Microstructures such as photonic crystal woodpile structures fabricated by using various resins are reviewed. The performance indicators of common resins for photonic crystal application are emphasised. (c) 2006 Elsevier B.V. All rights reserved.