Berlin 2005 – scientific programme

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HL: Halbleiterphysik

HL 42: Symposium: Photonic Crystals

HL 42.6: Talk

Monday, March 7, 2005, 17:30–18:00, TU P270

Sol-Gel Approaches to Photonic Crystal Systems — •Frank Marlow, Denan Konjhodzic, Helmut Bretinger , and Hongliang Li — Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr

A prerequisite for an efficient ”molding the flow of light” by photonic crystals is the molding of materials in desired nanostructures. Very often, conventional materials and processing techniques cannot fulfill the theoretical requirements for the materials and structures. Sol-gel methods enable the controlled introduction of porosity into the materials by the use of molecular or supramolecular templates. The porosity can be used for lowering the refractive index, for soft processing of the materials and for stress relaxation. Examples for this are ultra-low refractive index film used as supports for 2D photonic crystals, inverse opals with a skeleton-like unit cell filling and ferroelectric films with high transparency and good structuring possibilities. Detail results will be described on mesoporous silica films with a refractive index of 1.14 and on their use in 2D photonic crystals waveguide systems. The films are synthesized by a template-modified sol-gel process using triblock copolymers.[1] Furthermore, the structure tuning possibilities of inverse opals and their photonic properties will be investigated. Here materials with new possible bandgaps can be constructed.[2] Finally, first investigations of sol-gel processed ferroelectric PZT films will be shown. They can lead to switchable photonic crystals.
[1] M. Schmidt, G. Boettger, M. Eich, W. Morgenroth, U. Huebner, H. G. Meyer, D. Konjhodzic, H. Bretinger, F. Marlow, Appl. Phys. Lett. 85 (2004) 16.
[2] F. Marlow, W. Dong, ChemPhysChem 4 (2003) 549.