Development In Photonics

Nanostructure Switches

A team of researchers from Lomonosov Moscow State University and the Australian National University in Canberra has made breakthroughs in the area of nanostructure switches. The mixed team has created an ultrafast all-optical switch on these nanostructures. What this means is that computers in future may be able to transfer data at a high speed. The article was published in the Nano Letters journal.


The work they have done is classified as a development in photonics, the same field that kicked off with the invention of lasers. Where electronics use electrons to transmit data and power, photonics use light. The main benefit of photonics is that photons do not interact with each other. This means they also address the data transmission problem much better than electrons, and are more useful when conveying more instructions in a second.


Electronic transistors – on which electronic devices run – have a typical scale of less than 100 nanometers, while photonic transistors measure up to several micrometers. Before this, crafting a nanostructure such as plasmonic nanoparticles meant you would get low efficiency and significant losses. This made it a challenge to make a compact photonic switch.


It was only three years back that is was discovered the silicon nanoparticles show strong resonance in the visible spectrum. The result is that light waves on sub wavelength scales show strong localization of light. It was only when the Nano Letters journal article came out that it was noted the discovery could catalyze the development of a compact switch.


The fabrication of nanoparticles was done in the Australian National University by e-beam lithography and then plasma etching. After this, the samples were brought to Moscow and experimental work resumed at the Faculty of Physics of Lomonosov Moscow State University, in the Laboratory of Nanophotonics and Metamaterials.


First author of the research article, Maxim Shcherbakov, said they used nonlinear optics methods to handle femtosecond light-matter, and that they eventually made device that could switch pulses at femtosecond rates. These switching speeds mean that data transmission and processing can one-day move at hundreds of terabits per second. It would be possible to download thousands of HD movies inside a second.


The all-optical switch works based on the interactions between two femtosecond pulses. These interactions are made possible through the magnetic resonance of the silicon nanostructures. The two pulses need to arrive within 100-fs of each other so the second one is dampered, and the switch works as intended.

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