Grant: Discovery Grants Program - Individual

I am building a research program to investigate the interaction between water-based structures/tissues and microwaves. As a uniquely high-index dielectric material at 2.5 GHz water can form resonant optical structures that enable the tight focussing of electromagnetic energy densities into tiny subwavelength volumes. The same phenomena-namely, morphology-dependent resonances (MDRs)-are being actively developed with visible/near-IR light at the nanoscale for a wide range of applications. Such applications include biosensors and bioassays, near-field and sub-resolution imaging, nano-emitters, and environmental/chemical sensing. Development of useful dielectric nanostructures hinges on the discovery and study of transparent materials with indexes of refraction of order 10. While no such material is known in the visible/near-IR, water's relative transparency and high index (~9) at microwave frequencies means that aqueous structures are likely acting as resonators in our cities and homes where microwave, Wi-Fi, and telecom GHz frequencies are ubiquitous. Furthermore, the ability to study MDRs with microwaves at centimetre scales provides exciting opportunities to investigate fundamental aspects of scattering phenomena in ways that cannot currently be done at the nanoscale. I propose a range of projects that aim to address both these approaches; namely, to study resonant water/microwave interactions as found phenomena and as a testbed for nanophotonic applications. This program will employ creative low-tech experimental approaches,  computer simulations, and analytical methods to explore electromagnetic resonances in aqueous cm-scale objects such as foodstuffs, hydrogels, and the human head.      My research program comprises mature projects, nascent projects, and longer-term initiatives: The study of resonant dimers and the process of dimerization-that is, how resonances in isolated aqueous spheres interact to yield a super-resonance in a proximal pair of objects-is an example of an ongoing mature study. Extension of such work from (mostly) simulations to experimental realization will involve establishing intensity- and polarization-controlled microwave excitation in free-space outside the confines of a household oven. Once polarization control is established, the longer-term goals of experimental confirmation of various resonant phenomena (such as non-radiating anapoles, prolate dimer hotspots, and heating in animal head models) will be targeted. At all stages, our research will develop important knowledge relevant to nanotechnology and microwave and biomedical engineering.      With a focus on interesting and translatable (bio)photonics, this research program will provide a venue for superior student training in experimental, theoretical, and computational methods. Students emerging from this program will have developed broad expertise in microwave photonics and valuable understanding of the scalability of resonant phenomena.