Nano-control of light pioneers new paths

Friday 8 April 2016

integrated nanophotonic chip

The breakthrough nanophotonic chip can harness the angular momentum of light, paving the way for next generation optical technologies. Image: RMIT University.

In summary

  • Researchers have developed a nanophotonic chip that offers new opportunities in generating, transmitting, processing and recording information.
  • Their research could also enable scientists to gain a deeper understanding of black holes.

An Australian-based research team has created a breakthrough chip for the nano-manipulation of light, paving the way for next generation optical technologies and enabling deeper understanding of black holes.

The team – from Swinburne University of Technology and RMIT in Australia and Jinan University in China – designed an integrated nanophotonic chip that can achieve unparalleled levels of control over the angular momentum (AM) of light.

The pioneering work opens new opportunities for using AM at a chip-scale for the generation, transmission, processing and recording of information. It 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 measures the amount of that dynamic rotation.

Lead author Haoran Ren, a PhD candidate at Swinburne, says: “If you send an optical data signal to a photonic chip it is critical to know where the data is going, otherwise information will be lost.

“Our specially-designed nanophotonic chip can precisely guide AM data signals so they are transmitted from different mode-sorting nano-ring slits without losing any information.”

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.

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.

Professor Min Gu, Associate Deputy Vice-Chancellor for Research Innovation and Entrepreneurship at RMIT, said the work offered the possibility of full control over twisted light, including both spin angular momentum (SAM) and orbital angular momentum (OAM).

“Due to the fact that rotating black holes can impart OAM associated with gravitational waves, an unambiguous measuring of the OAM through the sky could lead to a more profound understanding of the evolution and nature of black holes in the universe,” he said.

The research has been published online by the journal Science.