Engineers at Duke University have demonstrated a device capable of directing photons of light around sharp corners with little or no backscatter loss. This is necessary if electronic devices are ever to be replaced by light-based devices. An article about this was published in the journal Nature Nanotechnology.

This result was achieved by photonic crystals built on the concept of topological insulators. By carefully controlling the geometry of the crystal lattice, scientists were able to prevent light from entering it and transmitted it along its surface. Due to this, the device provides near perfect transmission of light around corners, although it is much smaller than previous designs.

According to the Semiconductor Industry Association, the number of electronic devices is growing so rapidly that by 2040 there will not be enough energy worldwide to power all of them. One possible solution is to use massless photons instead of electrons for data transmission. In addition to saving energy, photonic systems also promise to be faster and have higher throughput.

Photons are already used in some devices. One of the drawbacks of current technology is that such systems are ineffective at turning or bending light. Photons need to go around corners under microscopic conditions if they ever replace electrons in microchips.

Previous demos have also shown little loss in guiding photons around corners, but a new study by Duke scientists has done this in a rectangular device just 35 micrometers long and 5.5 micrometers wide – 100 times smaller than past work.

The scientists fabricated topological insulators using electron beam lithography and measured the transmission of light in a series of sharp turns. The result showed that only a few percent of the light was lost at each turn.

The researchers note that their device also has wide bandwidth, is compatible with semiconductor technologies, and operates at the wavelengths used in telecommunications today. Next, they plan to make their waveguide dynamically tunable in order to change its bandwidth. This will enable the device to be turned on and off at any time, which is also important for the implementation of photon-based optical technologies.