Santos, AbelAbell, Andrew D.Law, Cheryl Suwen2019-07-092019-07-092019http://hdl.handle.net/2440/119957Conventional analytical systems have intrinsic limitations that restrict their applicability, including high costs, bulkiness, time-consuming processing, and require highly trained personnel. This triggers an increasing demand of optical sensing technologies that can address these limitations, while offering enhanced sensing capabilities over benchmark analytical techniques. Current progress in nanotechnology is enabling development of rapid, sensitive, user-friendly, and cost-competitive optical sensors integrated into lab-on-a-chip platforms with broad applicability across different disciplines, including medicinal, industrial and environmental applications. This thesis presents the development of cutting-edge optical sensing systems based on the combination of nanoporous anodic alumina photonic crystals (NAA-PCs) and reflectometric interference spectroscopy (RIfS). Fundamental and applied advances of the proposed sensing systems towards ultrasensitive and selective detection of target analytes are achieved through rational structural engineering of NAA-PCs and surface chemistry architectures. A collection of NAA-PCs was generated by innovative pulse-like anodisation methods aimed at engineering the optical properties of these photonic crystals to harness light–matter interactions at the nanoscale. The sensing characteristics of these optical sensing systems in terms of selectivity and sensitivity were further optimised by engineering the surface chemistry architecture of NAA-PC platforms with multiple functional molecules. The sensitivity and reliability of the proposed sensing systems were demonstrated through real-time detection of heavy metal ions (i.e. gold (III) and mercury (II) ions) and other analytes. The work completed in this thesis advances both fundamental understanding and applied knowledge on the sensing performance of NAA-PCs with optimised geometrical, chemical and optical properties integrated with RIfS, pushing the boundaries of science a step closer to fully functional and marketable analytical tools for real-life medical, environmental, industrial and defence applications.enNanoporous anodic aluminaphotonic crystalsoptical sensingThesis