Graphene enables lightspeed circuitry
Purdue researchers open door to next-gen optics and circuits Metal Tech News – October 27, 2021
Last updated 11/16/2021 at 4:02pm
In a recent breakthrough by Purdue University, researchers have devised a method utilizing the remarkable properties of graphene to support unidirectional electromagnetic waves on its edge, more simply, a new form of potentially lightspeed communications.
The topological circulators developed by Purdue scientists are the smallest one-way routers of signals in the world and could be a breakthrough for on-chip, all-optical processing.
Circulators themselves are a fundamental building block in integrated optical circuits that have long since had challenges in miniaturization due to bulky components and the narrow bandwidth of current technologies.
However, the topological circulator developed by Purdue seems to overcome these inherent issues by being both ultra-subwavelength and broadband, enabled by a unique electromagnetic phase of matter.
To understand this, one must delve a little into topology or the study of how surfaces behave in different dimensions.
Generally discussed in mathematics, topology involves the properties of a geometric object that is seemingly preserved under continuous deformations, such as stretching, twisting, crumpling, and bending.
A prime example is a Mobius strip, which has only one surface and one edge. This can be easily constructed with a thin piece of paper and some tape; simply twist the paper and have both ends meet and tape together, creating a Mobius strip.
While seemingly complex, what Purdue has accomplished with graphene is a method of having light travel in one direction along the edge of the material. Furthermore, the signal would be "robust to disorder, imperfections, and deformation," as the researchers put it.
Not dissimilar to conventional integrated circuits, integrated optical circuits or photonic integrated circuits (PIC) is a device that uses light to function instead of an electric current. The major difference is that PICs provide information signals on optical wavelengths.
The primary application for PICs is in the area of fiber-optic communications, high-speed internet touting fiber-optic capabilities use photons to transmit data instead of electrons.
Which is generally seen as much faster, and at the speed of light, it is! Although not without limitations due to the inherent nature of the materials used to construct the cabling.
So, what does this have to do with graphene?
As graphene is a two-dimensional material, there is only a single plane with which a signal can travel along. Neatly ordered and firmly stuck carbon atoms that comprise the strongest and thinnest material known to Man, highly conductive and stable, the researchers at Purdue have utilized these innate qualities to transmit data along its edge.
These new "edge waves" are linked to a new topological phase of matter and symbolize a phase transition in the material, not unlike the transition from solid to liquid.
Basically, the data transmitted would not be interrupted in the event of stretching, twisting, crumpling, or bending.
Each day, new discoveries using graphene are coming to light, and presently, applications for this topological circulator include simple information routing. But, even more importantly, it also consists of the potential to connect between quantum and classical computing, bringing us that much closer to a new technological age.