Monday November 19, 2018

New Research into Bending Light Could Lead to Light-Based Computing

Engineers at Duke University have demonstrated a device that can bend light around tight corners with virtually no losses due to backscattering. The engineers have created a device that uses photonic crystals and the concept of topological insulators to allow light to pass on the surface while blocking it from traveling through the interior. This research could lead to photonic systems where electrons are replaced with light. For this to be true, photons must be able to traverse microscopic spaces such as in a microchip. Photonic systems will be faster than conventional microchips and have higher bandwidth.

Duke engineers had taken the original idea and devised a system that was 100 times smaller at just 35 micrometers long and 5.5 micrometers wide. The original concept used carefully controlled geometry to create the effect, but new research has done away with that requirement. The new research that was released on November 12th has yielded a "device that will work no matter its dimensions or geometry of the photons' path and photon transport is 'topologically protected,'" according to Mikhail Shalaev. "This means that even if there are minor defects in the photonic crystalline structure, the waveguide still works very well. It is not so sensitive to fabrication errors." "The researchers point out that their device also has a large operating bandwidth, is compatible with modern semiconductor fabrication technologies, and works at wavelengths currently used in telecommunications."

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"The smaller the device the better, but of course we're trying to minimize losses as well," said Wiktor Walasik, a postdoctoral associate in electrical and computer engineering at Duke. "There are a lot of people working to make an all-optical computing system possible. We're not there yet, but I think that's the direction we're going." Now the researchers are trying to make a waveguide that can be turned on or off at will--another important feature for all-optical photon-based technologies to ever become a reality.