They were published in Nature on May 11, local time.
Computers and Intelligence Todaycell phoneThe computational speed of the processor is given by field effect transistors. In the race to produce faster devices, these transistors continue to shrink in size to fit as many as possible together on a chip. Modern computers already operate at blazing speeds of several gigahertz, which means billions of computing operations per second. The latest transistors are only 5 nanometers in size, the equivalent of no more than a few atoms. There are limits to how far chipmakers can go, and at some point, it won’t be possible to make transistors any smaller.
light is faster
Physicists are working to control electronics with light waves. It takes about one femtosecond for a light wave to oscillate. Using light to control electrical signals could make future computers more than a million times faster, which is what Petahertz signal processing, or optoelectronics, is for.
From light waves to current pulses
Electronics is designed to transmit and process signals and data in the form of logical information, which uses binary logic. Alternatively, these signals may take the form of current pulses.
Researchers at the Laser Physics Chair have been studying how to convert light waves into electrical pulses for several years. The researchers used ultrashort laser pulses to illuminate a structure of graphene and gold electrodes in their experiments. Laser pulses induce waves of electrons in the graphene, which travel toward the gold electrodes, where they are measured as current pulses and can be processed as information.
real and virtual charges
Depending on where the laser pulse hits the surface, the electron wave propagates differently. This creates two types of current pulses, called real and virtual charges.
“Imagine that the graphene is a pool and the gold electrode is a basin of overflow. When the surface of the water is disturbed, some of the water will spill out of the pool. The real charge is like throwing a stone into the middle of the pool,” the “Once the generated waves reach the edge of the pool, the water overflows, like electrons in the middle of graphene excited by a laser pulse,” said Tobias Boolakee, lead author of the study and a researcher in the Laser Physics Chair. Like scooping water on the edge of the pool, there is no need to wait for the wave to form. For electrons, this happens so fast that it cannot be sensed, which is why it is called virtual charge. In this case, the laser pulse will be pointed to the graphene edge next to the gold electrode.” Both virtual and real charges can be interpreted as binary logic.
Logic using lasers
Laser physicists at FAU have been able to demonstrate through their experiments for the first time that this method can be used to manipulate logic gates – a key element in computer processors. Logic gates specify what to do with incoming binary information. The gate requires two input signals, here electron waves from real and imaginary charges, excited by two synchronized laser pulses. Depending on the direction and strength of these two waves, the resulting current pulses are either concentrated or wiped out. Once again, electrical signals measured by physicists can be interpreted as binary logic, 0 or 1.
“This is a great example of how fundamental research can lead to the development of new technologies,” said Ignacio Franco of the University of Rochester. “Through fundamental theory and its connection to experiment, we have discovered the difference between real and virtual charges. role, which opens the way to creating ultrafast logic gates.”
Tobias Booklakee added: “It may be a long time before this technology can be used on computer chips. But at least we know that lightwave electronics is a viable technology.”
