A new material produced by Juejun Hu and his team can be repeatedly stretched without losing its optical properties. Courtesy of the researchers
A team of scientists have devised a new method to create photonic devices that are stretchable and flexible without being damaged.
Researchers from the Massachusetts Institute of Technology (MIT), and several other institutions, used a specialized kind of glass called chalcogenide that can be made to stretch and bend when formed into a spring-like coil, while maintaining its desirable optical properties.
“You end up with something as flexible as rubber, that can bend and stretch and still has a high refractive index and is very transparent,” Juejun Hu, Ph.D., the Merton C. Flemings Associate Professor of Materials Science and Engineering, said in a statement.
During testing, the researchers found that spring-like configurations made directly on a polymer substrate can undergo thousands of stretching cycles with no detectable degradation in their optical performance.
The research team produced a variety of photonic components that were interconnected by the flexible, spring-like waveguides, all in an epoxy resin matrix, which was made stiffer near the optical components and more flexible around the waveguides.
Photonic devices process light beams directly, using systems of LEDs, lenses and mirrors fabricated with the same kinds of processes used to manufacture electronic microchips.
However, the majority of photonic devices are fabricated from rigid materials on rigid substrates because soft materials generally have a low refractive index that leads to a poor ability to confine a light beam.
This novel method could be used to produce photonic devices in cables that connect computing devices or in diagnostic and monitoring systems that could be attached to the skin or implanted in the body, flexing easily with the natural tissue.
Some of the applications also include skin-mounted monitoring devices that could directly sense optical signals, while simultaneously detecting heart rate, blood oxygen levels and blood pressure. The flexible, stretchable photonic circuits could also be used in applications where the devices need to conform to the uneven surfaces of other materials, including in strain gauges.
Hu said the research is still in the early stages and more work is needed.
“For it to be useful, we have to demonstrate all the components integrated on a single device,” he said.
