Researchers draw inspiration from nature to create 3D imaging
Did you know that many insects can see ultraviolet light? This is a higher frequency of light, which is invisible to the human eye. Insects’ eyes are composed of thousands of lenses which work together to provide a sophisticated image, and scientists say that the same technique can be used for 3-dimensional imaging.
Engineers and physicists at the University of Pennsylvania have shown how liquid crystals can be used to create compound lenses, which are akin to those in nature. Now, the researchers can grow lenses with controllable sizes by making full use of the geometry in which the liquid crystals like to arrange themselves. These lenses produce sets of images with different focal lengths, a property that could be used for 3D imaging. Moreover, they are also responsive to the polarization of light, a quality that is thought to help bees navigate through their environment.
The research group had also shown how smectic liquid crystal naturally self-assembled into flower-like structures when placed around a central silica bead. “Given the liquid crystal flower’s outward similarity to a compound lens, we were curious about its optical properties,” lead researcher Mohamed Amine Gharbi said.
Photolithography was used by the researchers to make the lenses. A sheet of micro-pillars was fashioned, and then the liquid crystal was spread on the sheet. This liquid crystal then adheres to the tops of posts at room temperature and transmits an elastic energy cue that causes the crystal’s focal conic domains to line up in concentric circles around the posts.
“Last time we had tiny flowers. Now they are 10 times bigger. If we ever wanted to mass-produce these lenses, we can use the same technique on arbitrarily large surfaces,” co-researcher Kathleen Stebe said.
By understanding the geometric relationships between the pillars’ size, the arrangement of the focal conic domains and the focal lengths of the micro-lenses produced by the researchers, the team has shown how to grow the compound lenses to order and, as co-researcher Stebe stated, can use the very same technique to produce the lenses in large quantities.
Throughout the years, researchers have been drawing their inspiration from various aspects of Nature; some have been successful, some have not. How far this particular research goes is yet to be seen.