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News Follow the links below for news and events related to the Attosecond Technology project.
Recent results
We made the first observation of “half-cycle cut-offs” (or HCOs) during high harmonic generation (HHG). HCOs are the highest frequency bursts of radiation emitted each half-cycle of the laser pulse during HHG. They have been theoretically predicted but had not previously been measured. We showed that HCOs are extremely sensitive to the sub-cycle (i.e. attosecond) details of the electric field evolution of the few-cycle driving laser pulse. In particular, the centre frequency of the HCOs was found to be a function of the CEP of the laser pulse, an essential parameter in the characterisation of few-cycle pulses, but notoriously difficult to measure. We used this to develop a completely new measurement technique of the CEP that offers many advantages over the handful of existing measurement techniques. Most notably it can work for much longer pulses (up to 5 cycles) and on a single-shot basis, This result was published in Nature Physics in January 20072, making the front cover of that issue. Nature Physics 3, p62, Jan 2007 Link to article - Link to News and Views
The motion of hydrogen and deuterium is captured in the first few femtoseconds after ionisation by an intense laser field, by observation of the high harmonic spectrum emitted on recollision of the ionised electron. This technique allows these first few moments of motion of the molecule to be captured with a resolution of <100 attoseconds. Science, 312, p424, April 2006 Link to article - Link to Perspectives - Link to BBC website coverage |
