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takyon writes:

http://www.ns.umich.edu/new/releases/24654-ultrashort-light-pulses-for-fast-lightwave-computers

"In the past few years, we and other groups have found that the oscillating electric field of ultrashort laser pulses can actually move electrons back and forth in solids," said Rupert Huber, professor of physics at the University of Regensburg who led the experiment. "Everybody was immediately excited because one may be able to exploit this principle to build future computers that work at unprecedented clock rates—10 to a hundred thousand times faster than state-of-the-art electronics."

But first, researchers need to be able to control electrons in a semiconductor. This work takes a step toward this capability by mobilizing groups of electrons inside a semiconductor crystal using terahertz radiation—the part of the electromagnetic spectrum between microwaves and infrared light.

The researchers shone laser pulses into a crystal of the semiconductor gallium selenide. These pulses were very short at less than 100 femtoseconds, or 100 quadrillionths of a second. Each pulse popped electrons in the semiconductor into a higher energy level—which meant that they were free to move around—and carried them onward. The different orientations of the semiconductor crystal with respect to the pulses meant that electrons moved in different directions through the crystal—for instance, they could run along atomic bonds or in between them.

Symmetry-controlled temporal structure of high-harmonic carrier fields from a bulk crystal (DOI: 10.1038/nphoton.2017.29) (DX)

Original Submission