AsianScientist (Mar. 24, 2017) – Researchers at the Institute for Basic Science (IBS) have used randomly-patterned nanoholes to increase the bandwidth of a plasmonic switching device by 40 times. Their results have been published in Nature Communications.
Microprocessors play a pivotal role in computers and have steadily increased the speed of information processing over the past several decades. However, due to technical limitations such as heat generation due to integration, the processing speed of semiconductors has remained at several gigahertz for the past decade.
To improve processor speed, many microprocessors are used in parallel. However, the electrical connection between the processors is slow, creating a bottleneck for data transfer. To solve this problem, many studies have been conducted to merge processors by using optical signals which are several hundred times faster than electrical signals.
One approach is using surface plasmons to mediate optoelectronic signaling. Using nanoantennas, optical signals are converted to surface plasmons, which then propagate through metal surface as electric signals.
Instead of the conventionally-used nanoantennas which are periodically arranged, a team led by Dr. Choi Wonshik, Associate Director of the IBS Center for Molecular Spectroscopy and Dynamics, used randomly arranged nanoholes. The disordered arrangement helped to minimize redundancy between the antennas and enabled each antenna to function independently. As a result, the device can provide 40 times wider bandwidth than existing antennas.
“We are proposing a new way to connect nanoscale microprocessors to ultra-high-speed optical communications,” said Choi.
Because each antenna can be used independently, the researchers were able to substantially increase the effective number of antennas. This in turn led to an increase in the number of channels in multiple-input multiple-output communication, increasing the information transmission bandwidth.
However, to exploit the benefit of the disordered arrangement of antennas, the team had to resolve an innate problem. Random multiple scattering by disorderly arranged nano antennas is unpredictable, and cannot be used for information transfer.
To overcome this problem, the researchers analyzed the patterns of multiple-scattered surface plasmons for various optical inputs and found a particular optical input signal that could send the desired signal to a particular microprocessor. The spatial light modulator was used to generate the identified optical input signal, allowing the surface plasmon to be controlled.
“Using this, we proved that we can transmit signals to six different microprocessors at the same time and proved that optical images are converted into plasmons,” Choi said.
The article can be found at: Choi et al. (2017) Control of Randomly Scattered Surface Plasmon Polaritons for Multiple-input and Multiple-output Plasmonic Switching Devices.
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Source: Institute for Basic Science.
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