Optical Switching at Record Speeds Opens Door for Ultrafast, Light-Based Electronics and Computers

University of Arizona, Tucson, AZ

Imagine a home computer operating one million times faster than the most expensive hardware on the market. Now, imagine that level of computing power as the industry standard.

University of Arizona researchers hope to pave the way for that reality using light-based optical computing, a marked improvement from the semiconductor-based transistors that currently run the world.

“Semiconductor-based transistors are in all of the electronics that we use today,” said Mohammed Hassan, assistant professor of physics and optical sciences. “They’re part of every industry — from kids’ toys to rockets — and are the main building blocks of electronics.”

Hassan led an international team of researchers that published the research article “Ultrafast optical switching and data encoding on synthesized light fields” in the February issue of Science Advances

Semiconductors in digital electronics rely on electrical signals to switch — either allow or prevent — the flow of electricity and data, represented as either “on” or “off.” Hassan said the future of electronics will be based instead on using laser light to control electrical signals, opening the door for the establishment of “optical transistors” and the development of ultrafast optical electronics.

Since the invention of semiconductor transistors in the 1940s, technological advancement has centered on increasing the speed at which electric signals can be generated. According to Hassan, the fastest semiconductor transistors in the world can operate at a speed of more than 800 gigahertz. Data transfer at that frequency is measured at a scale of picoseconds, or one trillionth of a second.

Computer processing power has increased steadily since the introduction of the semiconductor transistor, though Hassan said one of the primary concerns in developing faster technology is that the heat generated by continuing to add transistors to a microchip would eventually require more energy to cool than can pass through the chip.

In their article, Hassan and his collaborators discuss using all-optical switching of a light signal to reach data transfer speeds exceeding a petahertz.

While optical switches were already shown to achieve information processing speeds faster than that of semiconductor transistor-based technology, Hassan and his team were able to register changes in a light’s signal at the attosecond time scale. That means the transfer of data one million times faster than the fastest semiconductor transistors.

This was accomplished by taking advantage of a characteristic of fused silica, a glass often used in optics. Its reflectivity was instantaneously changed by using ultrafast lasers. They demonstrated the possibility of sending data at previously impossible speeds.

“This new advancement would also allow the encoding of data on ultrafast laser pulses, which would increase the data transfer speed and could be used in long-distance communications from Earth into deep space,” Hassan said. “This promises to increase the limiting speed of data processing and information encoding and open a new realm of information technology.”

For more information, contact Mohammed Hassan at This email address is being protected from spambots. You need JavaScript enabled to view it..

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