The researchers broke the record for the shortest pulse of electrons created, producing a signal just 53 attoseconds long, or 1/53 billionth of a second. This work could lead to even more precise electron microscopy that can capture still images that are atomically sharp, rather than just blurry. It can also speed up data transfer for computer chips.
Pulses of electrons are used to represent data in computers and to capture images in electron microscopes. The shorter the pulse, the faster the information can be transmitted.
Eleftherios Guriermacis The University of Rostock in Germany and his colleagues have worked to make the length of such pulses as short as possible.
The pulse of electrons produced by an electric field in a normal circuit is limited by the frequency at which electrons can oscillate in matter. According to Goulielmakis, the pulse should last at least half a cycle of these oscillations. This is because this cycle produces the “pushing force” of electrons.
Because light vibrates at a much higher frequency, his team uses short bursts of light to trigger pulses of electrons.
In 2016, Goulielmakis’ team created a flash of visible light lasting just 380 attoseconds. Using the same technique, the team now focused a laser to drop electrons from the tip of a tungsten needle into the vacuum.
The 53 attosecond electron pulse they detected was even shorter than the light pulse that caused it. Goulielmakis says he lasted one-fifth the time it takes an electron in a hydrogen atom to orbit its nucleus in Bohr’s model of the hydrogen atom.
This short electron pulse allows the electron microscope to focus on a shorter slice, much like slowing down the shutter speed of a camera, revealing particle motion more clearly.
“sometimes [in electron microscope images] You can see that the atoms are not very confined. It’s a little blurry. Resolution is not necessarily bad. Because the electrons aren’t stationary at a specific point, right? They’re just creating clouds around the atom. Attosecond electron pulses are fast enough to capture electrons in motion and help increase resolution. “
“If we could use attosecond electron pulses to create an electron microscope, we would have enough resolution to not only see the atoms in motion, but how the electrons jump between those atoms. You can see it,” says Goulielmakis.
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