Researchers at Singapore University of Technology and Design (SUTD) have developed the use of chalcogenide nanostructures to tune Mie resonances in the visible spectrum.
Next-generation video displays will need optical nanoantennas, devices that use nanotechnology to mix and interfere with light beams to produce color and even holograms.
These nanoantennas have been developed previously to produce color images but they are fixed and cannot be tuned back and forth.
The SUTD solution is smaller than a single strand of human hair and can be switched between two optical states using heat to induce phase transistors.
“We demonstrate phase change nanodiscs’ ability to interfere and manipulate visible light — that is the first step towards a video hologram display,” said Robert Simpson, associate professor and the principal investigator at SUTD.
The technology relies on phase change materials, which are typically used in storage devices. Instead of using germanium-antimony-tellurium alloys, researchers used antimony trisulphide, an abundant Earth material. They found this material can be switched at a high speed to create tunable vivid colors.
To use the material, SUTD has to develop a new nanofabrication method to create antimony trisulphide nanostructures with specific optical properties.
They used femtosecond laser pulses to switch the optical state of these particles to ensure the optical properties and resonances could be reversibly switched. Substantial optimization was also necessary to find the conditions that would lead to this state without vaporizing the nanoparticle structures.
SUTD said the work paves the way for high resolution color displays, holographic displays and miniature lidar scanning systems.
The next phase is to change material to other programmable photonic applications and foster deals for full potential of the material in these applications.
“Our work clearly demonstrates that reversible switching is possible, but for practical devices, we also need to develop an elegant, integrated system to electrically address and control the optical state of the nanoparticles,” Simpson said. “We are currently working on these technologies, and we hope that this paper will inspire the wider research community to further extend the capabilities of these important chalcogenide nanoparticles.”