| Summary: | Patterning, the utilisation and manipulation of geometric properties, is important both for the rational design of technological devices and also to the understanding of many natural phenomena. In this thesis I examine the way in which micro and nano patterning can alter optical properties across a large range of wavelength scales and how these novel phenomena can be utilised. Micro patterned electrodes can tune the geometry of radio frequency electric fields to generate dielectrophoretic microfluidic devices. These devices use the dielectrophoretic force to sort, position and characterise the properties of micro and nano particles. I develop a new image processing algorithm that radically improves experimental efficiency allowing for real-time supervisor free dielectrophoretic characterisation of nanoparticles. Metamaterials are composite structures that have repeating units that are much smaller than the wavelength of radiation they are designed to work with. The optical properties of the materials are derived from these units rather than the bulk characteristics of the materials they are composed of. I demonstrate the development of novel THz metamaterial absorber devices. These devices provide a means to design and control the absorption of THz radiation, modulating bandwidth, polarization dependence and frequency in a form that is readily integrable with other standard fabrication processes. Finally by periodically patterning materials on the nanometer scale I demonstrate the development of novel photonic crystal devices and complementary optical components. In these devices the periodicity of the electromagnetic wave is modulated by the periodicity of the structures themselves resulting in band gaps and resonances analogous to the band gaps and defect states found commonly in semi-conductor physics. I demonstrate the theory, fabrication and measurement of these devices using novel broadband supercontinuum sources and propose a future application for biosensing. Further topics covered in the appendix include the development of a spin out technology, a $100 open source atomic force microscope developed while spending time in China. Finally I examine the role of patterning for optimising the performance of nanomechanical cantilever biosensors, and show how geometrical effects on the microscopic scale are crucial to understanding the workings of the vancomycin family of antibiotics, as screened using microcantilevers. Portions of this report are edited extracts from published articles resulting from this work, a full list of which is given in Appendix A.
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