Researchers at the University of Oregon and the University of Canterbury, New Zealand are studying the possibility of using fractal electrodes as efficient interfaces between retinal implants and functioning retinal neurons. They’re using nanocluster deposition to create fractal electrodes, that they call nanoflowers (see side image), that should provide better coupling than traditional electronic chips.
From an article by Richard Taylor of U of Oregon in Physics World:
During the deposition process, the nanoflowers nucleate at points of roughness on the substrate. Therefore, when nanoflowers are grown on top of the implant’s photodiodes, the surface roughness will be exploited to "automatically" grow the nanoflowers, making this a highly practical process for future implants. One challenge of the growth process lies in reducing nanocluster migration along nanoflower edges, which smears out the fine branches. This can be achieved by tuning the cluster sizes (which range from several nanometres up to hundreds of nanometres) and adjusting their deposition rate.
The nanoflowers can be grown to match the size of the photodiodes (20 µm), and will feature branch sizes down to 100 nm. Many of the gaps between the fractal branches will therefore be smaller than the wavelength of visible light, opening up the possibility of using the physics of fractal plasmonics to "super lens" the electromagnetic radiation into the photodiodes.
Significantly, the inherent advantages of the nanoflower electrodes lie in adopting the fractal geometry of the human eye rather than the Euclidean geometry of today’s cameras.
UOregon statement: Forecast calls for nanoflowers to help return eyesight…
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