Bioinspired design of functional optical structures

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The application of cellular plant tissue as three-dimensional morphogenetic template for microstructure patterning of optical functional materials in the μm and sub-μm length scale will be explored. Processing of random as well as periodical arrays of highly oriented wave guide pillars of X-ray storage phosphor (XRSP) cera-mics based on rare earth doped earth alkaline aluminate will be investigated. High resolution X-ray imaging systems are of increasing importance in medical diagnosis systems as well as various other fields including quality control, materials science or security inspection. Adopting the principle of apposition compound eyes, where the individual microlens facets and wave guiding elements are optically isolated from one another, the biotemplated XRSP arrays offer a high potential for optimising spatial resolution of X-ray storage imaging systems. Biotemplates of suitable three dimen-sional pore channel morphology will be selected from Gymnospermae which offer a uniform tracheidal cell anatomy. A diffusional flow reactor will be used to control ma-terial transport and local ion concentration in the template membrane. Major scientific questions to be addressed centre on the role of the biotemplate for governing the microstructure formation. While the individual cell morphology provides a unique compartment for controlling nucleation and crystal growth in the pore lumae (large single crystalline domains) or in the cell wall (nano crystalline), the tissue anatomy is supposed to determine the geometrical arrangement in the pillar arrays. Though experimental work concentrates on SrAl2O4:Eu to be processed into XRSP arrays the principles of microstructure patterning by use of three dimensional morphogenetic biotemplates might be of increasing interest for other ceramic material systems and applications such as for example large area piezoelectric sensor and actuator arrays.