Bioinspired design of functional optical structures

将探索细胞植物组织作为三维形态发生模板在μm和亚μm长度尺度上的光学功能材料微结构图案化中的应用。研究了稀土掺杂碱式铝酸盐X射线存储荧光粉(XRSP)陶瓷的随机和周期性的高取向波导柱阵列的加工。高分辨率X射线成像系统在医疗诊断系统以及包括质量控制、材料科学或安全检查在内的各个领域都发挥着越来越重要的作用。生物模板化XRSP阵列采用对位复眼原理，其中单个微透镜小面和波导元件彼此光学隔离，为优化X射线存储成像系统的空间分辨率提供了高潜力。将从裸子植物中选择合适的三维孔道形态的生物模板，提供统一的管胞解剖结构。扩散流反应器将被用来控制模板膜中的材料传输和局部离子浓度。需要解决的主要科学问题集中在生物模板在管理微结构形成方面的作用。虽然单个细胞的形态为控制孔腔(大的单晶域)或细胞壁(纳米晶体)中的成核和晶体生长提供了独特的隔间，但组织解剖学被认为决定了柱子阵列中的几何排列。虽然实验工作主要集中在将SrAl2O4：Eu加工成XRSP阵列，但利用三维形态发生生物模板进行微结构图案化的原理可能会对其他陶瓷材料系统和应用越来越感兴趣，例如，大面积压电传感器和致动器阵列。

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.