This visualization from CSCS in Switzerland shows the world’s smallest integrated switch.
Researchers working under Juerg Leuthold, Professor of Photonics and Communications at ETH Zurich, have created the world’s smallest integrated optical switch. Applying a small voltage causes an atom to relocate, turning the switch on or off. ETH Professor Mathieu Luisier, who participated in this study, simulated the system using Piz Daint Supercomputer. The component operates at the level of individual atoms. The team’s latest development was recently presented in the journal Nano Letters.
“The simulation at Piz Daint was essential in order to prove that the circuit works indeed with a single atom,” Lusiser says.
Here’s how the modulator works: light entering from an optical fibre is guided to the entrance of the gap by the optical waveguide. Above the metallic surface, the light turns into a surface plasmon. A plasmon occurs when light transfers energy to electrons in the outermost atomic layer of the metal surface, causing the electrons to oscillate at the frequency of the incident light. These electron oscillations have a far smaller diameter than the ray of light itself. This allows them to enter the gap and pass through the bottleneck. On the other side of the gap, the electron oscillations can be converted back into optical signals.