An illustration of two laser pulses zapping the world’s fastest logic gates. (Image Credit: University of Rochester illustration / Michael Osadciw)
Something new in good old logic gates? Researchers at the University of Rochester recently developed the world’s fastest logic gates. These are up to a million times faster than conventional ones found in today’s computers, demonstrating the practicability of lightwave electronics. This uncanny speed boost was achieved by applying laser pulses to graphene and gold.
Logic gates operate by accepting two inputs, comparing them, and outputting a signal. For example, they output a 1 if the signals are a 1 or 0, along with other rules. Chips feature billions of logic gates, creating memory, processors, and electronic components. However, these experience a time delay measuring nanoseconds while processing inputs, quick enough for computers. Now, the team’s new logic gates outperform these by processing information in femtoseconds.
The researchers reached such a high speed by creating junctions made of an individual graphene wire that connects two gold electrodes. Hitting the graphene with two laser pulses stimulated the material’s electrons. These would then quickly move toward an electrode, where they generated an electric current. The team also altered the laser pulses’ phase, which generated one of two types of charge carriers that accumulated or offset each other. This results in a superfast logic gate, the very first proof-of-concept for lightwave electronics.
“It will probably be a very long time before this technique can be used in a computer chip, but at least we now know that lightwave electronics is practically possible,” says Tobias Boolakee, lead author of the study.
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