Researchers in Italy have created the shortest light pulse yet-a single isolated burst of extreme-ultraviolet light that lasts for only 130 attoseconds (billionths of a billionth of a second). Shining this ultrashort light pulse on atoms and molecules can reveal new details of their inner workings--providing benefits to fundamental science as well as potential industrial applications such as better controlling chemical reactions.
Working at Italy's National Laboratory for Ultrafast and Ultraintense Optical Science in Milan (as well as laboratories in Padua and Naples), the researchers believe that their current technique will allow them to create even shorter pulses well below 100 attoseconds.
In previous experiments, longer pulses, in the higher hundreds of attoseconds, have been created.
The general process for this experiment is the same. An intense infrared laser strikes a jet of gas (usually argon or neon). The laser's powerful electric fields rock the electrons back and forth, causing them to release a train of attosecond pulses consisting of high-energy photons (extreme ultraviolet in this experiment).
Creating a single isolated attosecond pulse, rather than a train of them, is more complex. To do this, the researchers employ their previously developed technique for delivering intense short (5 femtosecond) laser pulses to an argon gas target. They use additional optical techniques (including the frequency comb that was a subject of the 2005 Nobel Prize in Physics) for creating and shaping a single attosecond pulse.
The results are being presented this week (paper JThA5) at the Conference on Lasers and Electro-Optics and the Quantum Electronics and Laser Science Conference (CLEO/QELS). Expanded story at: http://www.cleoconference.org/media_center/lightpulse.aspx ; also see Sansone et al., Science, 20 October 2006.