Article ID Journal Published Year Pages File Type
5189897 Polymer 2005 10 Pages PDF
Abstract
A single-monomer acrylate resin (SR348, Sartomer) with an aromatic ketone photoinitiator (Irgacure 369, Ciba) has been developed to produce photonic crystal structures by two-photon photopolymerisation. Compared with more complex acrylate-based resins, this one-component resin is easily prepared. The material is homogeneous before and after photocuring and has a high photosensitivity. SR348 (ethoxylated (2) bisphenol A dimethacrylate) is a difunctional monomer, which generates an insoluble crosslinked network by free radical polymerisation. The polymerised material is thermally stable up to 300 °C. Its refractive index jumps from 1.54 to 1.59 upon polymerisation. Scanning electron microscopy images of photonic crystal structures reveal a minimum structural element size of approximately 300 nm. The photonic crystals were fabricated in a 40 layer woodpile structure at a layer-spacing of 500 nm and an in-plane rod spacing of 1.5 μm. Fundamental stop gaps were observed in the stacking direction at wavelengths of 1.9-2.3 μm dependent on the rod size. Suppression of infrared light transmission of as much as 40% in the stop gap region and gap/midgap ratios of up to 0.15 demonstrate the high degree of correlation of structural elements in three dimensions.
Related Topics
Physical Sciences and Engineering Chemistry Organic Chemistry
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