Abstract

Micro/nanofabrication based on femtosecond laser induced multiphoton polymerization is attracting a lot of attention as it enables to fabricate three-dimensional (3D) structures such as photonic crystals, plasmonic and metamaterial components, voids or channels, and many other components with complex geometry. By moving the laser focal point, 3D micro/nanostructures can be directly written in the photopolymer [1]. To date, several commercial and specially-designed photoresists have been employed. One such class of materials is photosensitive organic-inorganic hybrid sol-gels [2]. These materials can be easily prepared and, after photopolymerization, they are chemically and electrochemically inert and mechanically stable. The co-polymerization of a silicon alkoxide with another metal alkoxide has been shown to enhance the material mechanical stability and allow the modification of its refractive index [3]. The incorporation of germanium alkoxides in a photosensitive sol-gel is particularly interesting, as they possess high optical transparency in the visible and near-infrared part of the spectrum. Due to, germanium doping is widely used in fiber optics, it makes such photpolymer useful in integrated microoptical circuits. Using a material containing germanium, it is possible to manufacture microoptical components of similar material contents as the core of the optical fiber itself [4].

© 2011 Optical Society of America