Speed Test of Electrons at Unbelievable Levels Lays Groundwork for Next Wave of Electronics

For the next wave of technologically advanced electronics to become a reality, electrons need to send information at a thousand times faster than a thousand billion oscillations per second -- a number so huge that many people don't know that the numerical term for it is petahertz.

Researchers at ETH Zurich are the first to test how electrons react to petahertz fields. Current technologies rely on near terahertz speeds (or slower) which are a thousand billion oscillations per second.

The testing performed at ETH Zurich is the first step in determining whether electrons can be controlled at petahertz frequencies. ETH professor Ursula Keller led the team in subjecting a microscopic piece of diamond to a laser pulse that had an electric field frequency of about half a petahertz and observing how the electrons in the diamond reacted.

A pulse of ultraviolet light was used to measure the reaction of the electrons. The technology for such extreme measurements was only possible because of continued research spanning decades of developments in lasers.

Precision is necessary when timing the ultraviolet pulse and it can only last an attosecond. Adding to the almost impossible to comprehend mathematical concepts in this study, an attosecond is one quintillionth (10 ^-18 ) of a second.

The ETH Zurich team worked with a team from Tsukuba University in Japan to understand the reaction. A simulation of the reaction was created using a supercomputer.

"The advantage of the simulations compared to the experiment, however, is that several of the effects that occur in real diamond can be switched on or off," postdoctoral researcher at ETH Matteo Lucchini said in a release.

"So that eventually we were able to ascribe the characteristic absorption behavior of diamond to just two such energy bands."

The team went on to say that their ability to see the absorption effect, called the Franz-Keldysh effect, proves that electrons can be influenced at petahertz frequencies. Full text of the study can be found in the journal Science.