A new photonic material developed with the help of a scientist based in Cork has the potential to ensure significantly higher internet speeds with simultaneous reductions in power consumption in digital devices.
The breakthrough has been achieved by Dr Sebastian Schulz of the Tyndall National Institute and the Centre for Advanced Photonics and Process Analysis at Cork Institute of Technology in collaboration with scientists in Canada and Mexico.
The artificial material can be customised and potentially used in a range of devices including the smartphone, Dr Schulz said. It enables the production of thinner lenses for cameras and mobile phones. It could also enhance microscopy tools used in medicine and biology, which generate images viewed under a microscope.
Their technology, details of which have been published in the international journal Nature Photonics, combines two known concepts; "metamaterials" which consist of arrays of antennas, and a thin film of a non-linear material. In this instance, the antenna array is made from gold and the thin film from indium tin oxide (a transparent conductor typically used in solar cells and touchscreens).
Optical response
The new metamaterial has a much stronger optical response than is available in natural materials, and overcomes the limitation up to now of non-linear material, which either required a large amount of power or was very slow in transmission.
Most optical devices use linear material, as for example with glass, where light of a certain brightness is transmitted through the material and emerges from it at the same intensity.
Yet, nonlinear optical systems exist, where the behaviour depends on the amount of light entering the system, as with a green laser pointer. “In such systems, depending on the power, light can change colour, direction or even its speed, and the team would like to use these effects to manipulate light, for example to imprint data on light to reduce the power consumption of the internet.”
Critically, with their technology this change occurs on an extremely short timescale, he noted; “Within one millionth of one millionth of a second.” In addition, it overcomes the typical scenario with a non-linear lens where an image is degraded – ie becomes pixelated.
"Short response times are important, as the response time limits how many times a system can be switched per second and therefore the amount of data that can be processed," Dr Shulz added. "The short response time of our system makes it suitable for operation at THz [terahertz] speeds, 10 times faster than current core internet links."
Because the non-linear response of most materials is typically extremely weak, non-linear optics have rarely been used up to now. “Typical optical systems – ie ones using light, such as optical fibres used in the ICT industry – are linear. This means that the behaviour is independent of the amount of light in the system: if the incident light is doubled, the amount of light exciting the system is doubled.”
Dr Schulz is working in conjunction with a team directed by Prof Robert Boyd, a pioneer and global leader in photonics, at the University of Ottawa, and researchers at Tecnológico de Monterrey in Mexico. The next step, he said, was to demonstrate the applications that arise from using their new artificial material, before developing it in an industrial setting.
