New Frontiers in Plasmonic Metamaterials: Flat-Lens Microscopy and Tractor Beaming

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A renaissance in optics has been sparked by the recent possibility of creating materials from the ground up with optical properties that are impossible to find in nature. Such materials, known as metamaterials, are based on the principle of "artificial atoms" having properties defined by morphological features sculpted on scales well below the wavelength of light.  ***When wavelengths are just hundreds of nanometres, it becomes difficult to fabricate artificial atoms with sufficient spatial resolution. A promising route to overcome this limitation is to use "plasmonic" metamaterials that transform light into shorter-wavelength oscillations known as surface plasmon polaritons (SPPs)- light waves bound on metallic surfaces.  These materials offer exciting new ways to mould light at UV to visible frequencies, a spectral region fundamentally important for human vision, displays, solar technologies, and microscopy.  Recent work has already shown that plasmonic metamaterials can be tailor-made to mimic exotic properties linked to a hypothetical negative-index medium, such as light bending the "wrong" way or light pressure that pulls rather than pushes.  ***My research program uses plasmonic metamaterials to realize new forms of negative-index behaviour based on the configuration of ultra-thin metallic and dielectric layers.  My past work has shown that such systems provide a platform to understand how SPPs conspire to elicit negative-index behaviour and can be used as a building block to make unique optical elements such as flat lenses. The proposed research has two goals. The first is to find recipes for new types of flat lenses having some of the desirable traits found in typical lenses, such as transparency over the visible spectrum. The second is to explore how and why plasmonic metamaterials can re-coil towards a light source, a form of tractor beaming yet to be fully understood. The methodology consists of simulations to model optical and opto-mechanical interactions in plasmonic metamaterials and experiments to validate their use for imaging and tractor beaming.  Tractor-beaming measurements will be based on visualizing tiny, light-driven displacements in a scanning electron microscope, the first experiment of its kind in Canada.***Flat lenses hold promise for innovative microscopes that can be used to image over large areas, yet made at a low cost using spray-on fabrication. Efforts to better understand tractor beaming will provide new perspectives on the momentum of light in matter, the topic of a lingering debate that leaves the foundations of electrodynamic theory unsettled.  HQP gain high-technology skills that are valuable to Canada's growing technology sector and support modernization of its resource sector. Entrepreneurship training opportunities will equip HQP with the skills to lead others and build companies.**