Attosecond Method Captures Electron Movements

A group of scientists at Technische Universität Wien in Austria, Universität Bielefeld in Germany and Max Planck Institut für Quantenoptik in Garching, Germany, has used ultrashort pulses of soft x-rays and laser light to investigate atomic electron dynamics on the scale of the Bohr orbit time -- approximately 150 attoseconds. The team reported the work in the Feb. 26 issue of Nature.

The researchers' experimental setup, which they call an atomic transient recorder, comprises a source of 250-attosecond pulses of 93-eV x-rays, a source of 5-fs pulses of 750-nm laser light, and a streak camera that they modified for the experiment. The x-rays excite a neon target to emit photoelectrons, which are probed with the linearly polarized laser to yield maps of their momentum distributions.

The scientists calculate that the current setup can resolve events that occur 100 attoseconds apart, and they suggest that the approach will enable time-domain metrology studies down to a resolution of 24 attoseconds -- the atomic unit of time.