Ultrafast laser on graphene creates “the world’s fastest petahertz quantum transistor.”
Researchers manipulate electrons in graphene using pulses of light that last less than a trillionth of a second
Researchers from the Department of Physics in the College of Science and the James C. Wyant College of Optical Sciences demonstrated that by leveraging a quantum effect known as tunnelling recorded electrons bypassing a physical barrier almost instantaneously, a feat that redefines the potential limits of computer processing power.
“We have experienced a huge leap forward in the development of technologies like artificial intelligence software, but the speed of hardware development does not move as quickly,” Hassan said. “But, by leaning on the discovery of quantum computers, we can develop hardware that matches the current revolution in information technology software. Ultrafast computers will greatly assist discoveries in space research, chemistry, health care and more.”
From the University of Arizona website:
The team was originally studying the electrical conductivity of modified samples of graphene, a material composed of a single layer of carbon atoms. When a laser shines on graphene, the energy of the laser excites electrons in the material, making them move and form into a current.
Sometimes, those electric currents cancel each other out. Hassan said this happens because the laser’s energy wave moves up and down, generating equal and opposite currents on either side of the graphene. Because of graphene’s symmetrical atomic structure, these currents mirror each other and cancel each other out, leaving no detectable current.
But what if a single electron could slip through the graphene, and its journey could be captured and tracked in real time? That near-instant “tunnelling” was the unexpected result of the team modifying different graphene samples.
Using a commercially available graphene phototransistor that was modified to introduce a special silicon layer, the researchers used a laser that switches off and on at a rate of 638 attoseconds to create what Hassan called “the world’s fastest petahertz quantum transistor.”
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