Photonic crystals and plasmonic structures recorded by multi-exposure of holographic patterns

Abstract

Different technologies can be used for fabrication of photonic crystals such as: self-assembly of colloidal particles, ebeam lithography (EB), interference lithography (IL) and focused ion beam (FIB). Among them, the holographic lithography (HL) is the only technique that is able to fabricate both two-dimensional and three-dimensional photonic crystals, as well as plasmonic structures, in large areas. In this paper we demonstrate the use of the multi-exposure of two-beam interference patterns, with rotation of the sample around different axis, for fabrication of large areas 2D and 3 D photonic crystals and plasmonic structures. Using this technique, we achieved aspect ratios of about 4 in 2D photoresist templates recorded in 1 cm² glass substrates. In order to generate the 2D photonic band gap layers and plasmonic structures, we combine the use the high aspect ratio photoresist templates with shadow evaporation of appropriated materials, with a further lift-off of the photoresist. The optical properties of the recorded structures, both photonic and plasmonic, were measured to demonstrate the applicability of the technique.