Nanoscale Device Adapts Filtering Properties When Stretched
ADELAIDE and MELBOURNE, Australia — A stretchable nanoscale device that can filter specific colors while remaining transparent may one day be used in smart contact lenses to filter harmful optical radiation, transmit data and gather information.
Rendering of nanoscale glass structures that filter or manipulate light. Courtesy of RMIT/The University of Adelaide.
The device was developed by University of Adelaide researchers with expertise in the interaction of light with artificial materials working with researchers in materials science and nanofabrication at RMIT University.
The light manipulation relies on creating tiny artificial crystals, called dielectric resonators. The dielectric resonators currently only work for specific colours, but the flexible surface can be stretched to adjust the operation range.
"Manipulation of light using these artificial crystals uses precise engineering,” said professor Withawat Withayachumnankul of the University of Adelaide's School of Electrical and Electronic Engineering. "With advanced techniques to control the properties of surfaces, we can dynamically control their filter properties, which allow us to potentially create devices for high data-rate optical communication or smart contact lenses.
Associate Professor Madhu Bhaskaran, co-leader of the Functional Materials and Microsystems Research Group at RMIT, said the devices were made on a rubber-like material used for contact lenses.
"We embed precisely controlled crystals of titanium oxide, a material that is usually found in sunscreen, in these soft and pliable materials," she said. "Both materials are proven to be biocompatible, forming an ideal platform for wearable optical devices.
"By engineering the shape of these common materials, we can create a device that changes properties when stretched. This modifies the way the light interacts with and travels through the device, which holds promise of making smart contact lenses and stretchable colour changing surfaces."
Lead author and RMIT researcher Philipp Gutruf said the major scientific hurdle overcome by the team was combining high-temperature processed titanium dioxide with the rubber-like material, and achieving nanoscale features.
"With this technology, we now have the ability to develop light weight wearable optical components which also allow for the creation of futuristic devices such as smart contact lenses or flexible ultrathin smartphone cameras," Gutruf said.
The work, published in ACS Nano (doi: 10.1021/acsnano.5b05954), was undertaken at RMIT's Micro Nano Research Facility and supported by the Australian Research Council.
- A transparent optical component consisting of one or more pieces of optical glass with surfaces so curved (usually spherical) that they serve to converge or diverge the transmitted rays from an object, thus forming a real or virtual image of that object.
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