Theoretical calculations show graphene's potential for controlling nanoscale light propagation on a chip

December 5, 2012
Theoretical calculations show graphene’s potential for controlling nanoscale light propagation on a chip
Plots showing that surface plasmons are more confined when propagating along on a monolayer of graphene (G) than they are along a thin film of gold (Au). Credit: 2012 A*STAR Institute of High Performance Computing

Semiconductors have revolutionized computing because of their efficient control over the flow of electrical currents on a single chip, which has led to devices such as the transistor. Working towards a similar tunable functionality for light, researchers from the A*STAR Institute of High Performance Computing (IHPC), Singapore, have shown how graphene could be used to control light at the nanometer scale, advancing the concept of photonic circuits on chips.

Graphene, which is made from a single layer of , has excellent electronic properties; some of these are also useful in photonic applications. Usually, only metals are able to confine light to the order of a few nanometers, which is much smaller than the wavelength of the light. At the surface of metals, collective oscillations of electrons, so-called 'surface plasmons', act as powerful antennae that confine light to very small spaces. Graphene, with its , shows similar behavior to metals so can also be used for plasmon-based applications, explains Choon How Gan of IHPC, who led the research.

Gan and co-workers studied theoretically and computationally how surface plasmons travel along sheets of graphene. Even though graphene is a poorer conductor than a metal, so plasmon propagation losses are higher, it has several key advantages, says team member Hong Son Chu. "The key advantage that makes graphene an excellent platform for plasmonic devices is its large tunability that cannot be seen in the usual ," he explains. "This tunability can be achieved in different ways, using electric or magnetic fields, optical triggers and temperature."

The team's calculations indicated that surface plasmons propagating along a sheet of graphene would be much more confined to a small space than they would traveling along a (see image). However, the team also showed that would travel far better between two sheets of graphene brought into close contact. Furthermore, by adjusting design parameters such as the separation between the sheets, as well as their electrical conductivity, much better control over surface plasmon properties is possible.

In the future, Gan and his co-workers plan to investigate these properties for applications. "We will explore the potential of graphene plasmonic devices also for the terahertz and mid-infrared regime," he explains. "In this spectral range, graphene plasmonic structures could be promising for applications such as molecular sensing, as photodetectors, or for optical devices that can switch and modulate light."

Explore further: Highly sensitive graphene biosensors based on surface plasmon resonance

More information: Gan, C. H., Chu, H. S. & Li, E. P. Synthesis of highly confined surface plasmon modes with doped graphene sheets in the midinfrared and terahertz frequencies. Physical Review B 85, 125431 (2012). prb.aps.org/abstract/PRB/v85/i12/e125431

Related Stories

Scientists first to observe plasmons on graphene

June 20, 2012

With a beam of infrared light, scientists have sent ripples of electrons along the surface of graphene and demonstrated that they can control the length and height of these oscillations, called plasmons, using a simple electrical ...

Recommended for you

Graphene under pressure

August 25, 2016

Small balloons made from one-atom-thick material graphene can withstand enormous pressures, much higher than those at the bottom of the deepest ocean, scientists at the University of Manchester report.

Designing ultrasound tools with Lego-like proteins

August 25, 2016

Ultrasound imaging is used around the world to help visualize developing babies and diagnose disease. Sound waves bounce off the tissues, revealing their different densities and shapes. The next step in ultrasound technology ...

Nanovesicles in predictable shapes

August 25, 2016

Beads, disks, bowls and rods: scientists at Radboud University have demonstrated the first methodological approach to control the shapes of nanovesicles. This opens doors for the use of nanovesicles in biomedical applications, ...

Neuromorphic computing mimics important brain feature

August 18, 2016

(Phys.org)—When you hear a sound, only some of the neurons in the auditory cortex of your brain are activated. This is because every auditory neuron is tuned to a certain range of sound, so that each neuron is more sensitive ...

'Artificial atom' created in graphene

August 22, 2016

In a tiny quantum prison, electrons behave quite differently as compared to their counterparts in free space. They can only occupy discrete energy levels, much like the electrons in an atom - for this reason, such electron ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.