Behold the Zeptosecond: Scientists Finally Record Atomic Event With Trillionth of a Billionth of a Second

Scientists for the first time have recorded an internal atomic event on a zeptosecond, as in a trillionth of a billionth of a second. This can shed tremendous insights to the inner workings of atoms, especially when light breaks down electrons too fast for modern observation tools to see.

At least until now. Laser physicists at LMU Munich and the Max Planck Institute of Quanum Optics (MPQ) have been able to measure the duration of such an incidence. This is called photoionization , an event where an electron exits a helium atom after interaction with light.

They were able to do it in under zeptoseconds, or a trillionth of a billionth of a second. This will be the first absolute determination of the timeline of the photoionization process. 

By the time a photon interacts with two electrons in a helium atom, not only does change happen too fast, changes also happen at a quantum level. The rules state that either the entire energy of the photon is inserted into an electron, or the energy is distributed. Regardless, one electron will always be ejected away.

The "ejection," called photoemission, was first discovered by Albert Einstein. However, in order to observe this, you have to have a camera with unrealistic shutter speed. The entire process takes place between five to 15 attoseconds -- or almost barely an instant.

According to Science Daily, the Munich scientists were able to use an improved method of measurement and captured the events on timescales down to 850 zeptoseconds. Researchers directed an extremely ultraviolet pulse onto a helium atom for an entire attosecond. At the same time, they also fired a second infrared laser at the target for four femtoseconds. The event resulted in an electron ejection that was detected by the infrared laser pulse.

By determining whether or not the electron speeds up or slows down based on the electromagnetic field at the pulse, scientists were able to check just how fast the photoemission event took place. They were also able to find how the energy is distributed between the two electrons in the final attoseconds before emission. 

Martin Schultze, a specialist in laser physics at LMU, said determining photoionization in helium is the most complex so far. This experiment will help "reconcile theory and experiment" as scientists will be able to derive the complete wave mechanical description of electrons and its ionized helium parent atom.