Numerical modelling of nanoporous anodic alumina photonic structures for optical biosensing

Identifier:  TDX:2902

Handle: https://hdl.handle.net/20.500.11797/TDX2902

Authors:  Bertó Roselló, Francisco

Abstract:
Some materials shown particular physical, optical and chemical properties at the nanoscale. The nanotechnology permits to scientist enhance their properties modifying the matter structure at this level and take advantage of them for the development of new devices and applications. Particularly important is the research in biosensing in order to obtain more sensitive and reliable devices with a view for their deployment to society in the form of cost-effective and reliable diagnostic systems. The manufacturing of such devices in some cases implies the manipulation of the light in these materials at the nanoscale, for which it implies to have a deep knowledge of the optical behaviour of the structure. In this sense, the election of the appropriate material is decisive in the development of biosensing devices. Nanoporous anodic alumina (NAA) is a self-ordered porous material which their optical properties in the visible, their great tunability of the structure, their ability to act as a holder or scaffold of small objects and their stability under biological conditions make it especially appropriate as a platform for the development of optical biosensors. Theoretical studies on the NAA optical properties is a fundamental field of research. The numerical modelling of these properties permits to understand their relationship with the structural features of the NAA, providing a conceptual framework for the analysis of their optical behaviour. In this thesis, we have analyzed the suitability and developed several predictive models for the optical properties of the NAA valid in a wide range of geometrical characteristics. Subsequently our simulation model has been applied to study the suitability of two types of gold-coated NAA structures as a platform for reflectometric-based plasmonic biosensors. Finally, a theoretical study of the optical behaviour by means of numerical modelling of gradient-index NAA (NAA-GI) based structures has been performed.