This image shows nanoscale glass structures that can filter or manipulate light. Image: RMIT/The University of Adelaide.
This image shows nanoscale glass structures that can filter or manipulate light. Image: RMIT/The University of Adelaide.

Researchers at RMIT University and the University of Adelaide, both in Australia, have joined forces to create a stretchable nano-scale device that can manipulate light. This required combining the University of Adelaide researchers' expertise in the interaction of light with artificial materials with the materials science and nanofabrication expertise available at RMIT University.

By utilizing nanoscale crystals, the device was able to manipulate light to such an extent that it could filter specific colors while still being transparent. This technology could one day lead to lenses that can filter harmful optical radiation without interfering with vision; more advanced versions could transmit data and gather live vital information or even show information like a head-up display.

The light manipulation relies on creating tiny artificial crystals termed ‘dielectric resonators’. These crystals are just 100–200nm in size, a fraction of the wavelength of light or over 500 times thinner than a human hair.

"Manipulation of light using these artificial crystals uses precise engineering," explained Withawat Withayachumnankul at 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. The current challenge is that dielectric resonators only work for specific colors, but with our flexible surface we can adjust the operation range simply by stretching it."

According to Madhu Bhaskaran, co-leader of the functional materials and microsystems research group at RMIT, 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 bio-compatible, 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 color changing surfaces."

According to Philipp Gutruf, RMIT researcher and lead author of a paper describing this work in ACS Nano, the major scientific hurdle that needed to be overcome 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 lightweight wearable optical components which also allow for the creation of futuristic devices such as smart contact lenses or flexible ultra-thin smartphone cameras," he said.

This story is adapted from material from RMIT University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.