Australian National University (ANU) physicists have developed new tech that controls the direction that light can and cannot travel in using nanoparticles, possibly discovering the path to cheaper, faster and more reliable internet.
In collaboration with colleagues from Singapore, China and Germany, ANU scientists have developed small translucent slides that produce two different images, depending on the direction that light passes through them. For example, at first, a slide may produce an image of a microscope but once it is flipped it produces an image of a collection of wheels and cogs, and this is but one of a large number of possibilities.
“Some particles allow light to flow from left to right only, others from right to left or the pathway might be blocked in either direction.”
“While the purpose of these images is mainly artistic, they demonstrate the potential for this new technology,” said Lei Wang from Southeast University in China.
“In real-world applications, these nanoparticles can be assembled into complex systems that would control the flow of light in a useful manner—such as in next-generation communications infrastructure,” said Wang.
What This Tech Means For Future Technology
The researchers note the breakthrough has the potential to create new light-based devices that may not only be the key to improved and less expensive internet, but also the basis for multiple technologies of the future.Kruk said that control of light flow at the nanoscale guarantees that light will go where it is supposed to go and avoid where it is not.
“We exchange enormous amounts of information with the help of light,” he said. “When you make a video call, say, from Australia to Europe, your voice and image get converted into short pulses of light that travel thousands of kilometres through an optical fibre over the continents and oceans.”
“Unfortunately, when we use current light-based technologies to exchange information a lot of parasitic effects might occur. Light might get scattered or reflected, which compromises your communication.”
Kruk said that many issues with current technologies would resolve if the light was guaranteed to flow exactly where it needed to.
“On a general note, the traffic control of light at the nanoscale that we are working on resembles similarities with the traffic control of electrical currents inside our computer chips (performed with nanoscale semiconductor diodes and transistors).”
“If information is handled using beams of light instead of electrical currents, certain tasks may be performed much faster.”
He said that the broad deployment of tiny tech that controls light flow could inspire technological and social changes reminiscent of those triggered by diodes and transistors—small components that control electricity flow.
“Control over the flow of electricity at the nanoscale is what ultimately brought us modern computers and smartphones. It is therefore exciting to envision the potential of our emerging technology for controlling the flow of light.”
Rival Technology
“A useful device for optical communications is an ”optical isolator“,” Kruk said in an email to The Epoch Times. “It allows light to propagate forward, but not backward thus protecting sophisticated communication systems from parasitic backward light scattering and reflections.”Although like the new tech developed by ANU, optical isolators can control light flow, they have drawbacks.
“Current optical isolators are quite big and expensive. Commercial isolators that we buy for our lab are typically several cm in size and cost over $1000,” he said.
“This research direction may reduce the size of optical isolators to the nanoscale (nanometre— one billionth of a metre) and also to reduce the cost to a fraction of a dollar.
“A wide deployment of small and cheap optical isolators would facilitate the development of faster, more reliable, and cheaper internet.”
However, Kruk said that, at the moment, there is an important difference between the newly developed slides and the optical isolators.
“Our slides change the colour of light, or in other words, the frequency at which the wave of light oscillates, while an optical isolator does not.”
Plans to Address the Device Altering Light Colour
Kruk said that nonlinear optics—how materials interact with very bright light beams, like lasers— is the fundamental physical principle that permits asymmetry in the way that light interacts with the translucent slide.“In this work, we employed nonlinear optical phenomenon called ”third-harmonic generation“ which triples the frequency of light.”
He said that, at the moment, the team is working on applying a second optical phenomenon called “nonlinear self-action”, which will maintain the asymmetrical transmission of light whilst sustaining its frequency.
“For the first step, we chose ”third-harmonic generation“ as it works well with silicon—one of the easiest materials for nanofabrication (computer chips are made from silicon, therefore nanofabrication techniques are very mature).”
“For the second step based on ”self-action“ (e.g. no frequency change), we research several a bit more exotic materials, and high-quality nanofabrication is one of the challenges.”
