Scientists Develop Light-Twisting Metamaterial


Scientists Develop Light-Twisting Metamaterial

22 July 2014

A new type of metamaterial able to rotate the polarisation of light and open the door for major developments in photonics has been discovered by a team of scientists from the Australian National University (ANU).

The artificially-created properties of the material spring from the asymmetry of its molecule - a pattern of tiny metal shapes, called meta-atoms. The research team obtained optical rotation by using pairs of C-shaped meta-atoms, one suspended over the other via a fine wire. When light reaches the pair only the top one rotates, making the system asymmetric.

According to lead author Mingkai Liu, a PhD student at ANU, the metamaterial's most important property is its responsiveness to light, which opens the door for scientists to develop metamaterial-based opto-electronic devices to replace today's much less efficient electric ones. To achieve that, they need a way to actively control the properties of light - one of which is its polarisation.

The movement from electronic-based devices to photonic ones is comparable to the increase of efficiency in signal transmission achieved when fiber optic cables replace electric ones. Scientists estimate that it will also be useful for reducing humanity's carbon footprint. Currently, electronics is estimated to be responsible for 2% of the carbon emitted into the atmosphere, while photonics have no carbon footprint whatsoever.

The idea to use meta-atoms, hanging by a string - making them easier to rotate - came to Liu after he found a piece of wire in his washing basket, he explained.