Chinese scientists say they slowed down light to improve microchips

That could improve the performance of these microchips – known as photonic chips – and their applications in light sensing, communications and computing.

The research was carried out by a team from the Shenzhen Institute of Advanced Technology, under the Chinese Academy of Sciences. They published their findings in the peer-reviewed journal Nano Letters on January 5.

Photonic chips use photons instead of electrons in their circuits. When used for calculation, their accuracy is approaching that of electronic chips, but photonic chips have the advantage of using less power and they are faster.

While the speed of light in a vacuum is a constant and cannot be exceeded, it can be slowed down in other media, meaning it can be manipulated more – which is crucial in designing photonic chips.

“When light is slowed down, the energy density of the light increases,” said Dr Li Guangyuan, a researcher of optical engineering at the Shenzhen institute who led the study.

“This means that with the same device length, the effective distance for the light to interact becomes longer – essentially enhancing the performance of a photonic device.”

Li’s team designed a photonic chip in a way that slowed down the light by more than 10,000 times. They said this was done with a greatly reduced loss of energy, which was only about 20 per cent of the loss seen in previous attempts.