Laser interaction in sol-gel based materials - 3-D lithography for photonic applications

As an example for laser interactions with polymer materials, inorganic-organic hybrid polymers were polymerized with femtosecond laser pulses, making use of two-photon absorption (TPA) processes. The material was synthesized by catalytically controlled polycondensation reactions, resulting in a storage-stable resin which is built up by inorganic (-Si-O-Si-) nm-size units which are organically functionalized with typically (oligo-)methacryl and styryl moieties, respectively. This results in materials which can be patterned by single- or two-photon absorption. The latter method allows one to directly write arbitrary structures in three dimensions into the hybrid polymer material with a resolution down to 200 nm or even below. The materials and the patterning process will be discussed with respect to applications in photonic devices. (c) 2005 Elsevier B.V. All rights reserved.