UK team delivers shortest light pulses
Imperial College researchers have developed a technique for delivering attosecond (10-18s) ultra-violet pulses.
Called ‘high harmonic generation’ (HHG), it involves initially producing long wavelength pulse from a femtosecond (10-15s) laser.
“The near-infra-red pulses are corralled through a waveguide and a series of specialised mirrors, causing them to be compressed in time,” said the American Institute of Physics (AIP), which has published the work in its journal ‘Review of Scientific Instruments‘. “With their waveforms precisely controlled, these compressed pulses are then focused into a gas target, creating an attosecond burst of extreme ultraviolet radiation. Such pulses are the shortest controllable light pulses available to science.”
Accurate measurements of the pulses are possible with the set-up, said the AIP, and they can be delivered with other precisely synchronised laser pulses.
“Though it incorporates many novel features, our system builds on a decade of research conducted by physics groups around the world,” said Imperial project leader John Tisch.
The pulses can be used to probe the dynamics of electrons in matter in real-time.
“Understanding how matter works at the level of its electrons is likely to lead to new scientific tools and to novel technologies,” said fellow Imperial researcher Felix Frank.