Nano-control of light enables understanding of black holes

The work opens opportunities for using AM at a chip-scale for the generation, transmission, processing and recording of information, and could also be used to help scientists better understand the evolution and nature of black holes.

While traveling approximately in a straight line, a beam of light also spins and twists around its optical axis. The AM of light, which measures the amount of that dynamic rotation, has attracted tremendous research interest in recent decades.

A key focus is the potential of using AM to enable the mass expansion of the available capacity of optical fibres through the use of parallel light channels - an approach known as "multiplexing".

But realising AM multiplexing on a chip scale has remained a major challenge, as there is no material in nature capable of sensing twisted light.

"By designing a series of elaborate nano-apertures and nano-grooves on the photonic chip, our team has enabled the on-chip manipulation of twisted light for the first time," Gu said.
"The design removes the need for any other bulky interference-based optics to detect the AM signals.

The team devised nano-grooves to couple AM-carrying beams into different plasmonic AM fields, with the nano-apertures subsequently sorting and transmitting the different plasmonic AM signals.

As well as laying the foundation for the future ultra-broadband big data industry and providing a new platform for the next industry revolution, the research offers a precise new method for improving scientific knowledge of black holes.