Future Light Sources

The aim of this research is to develop new methods in the generation of high brightness x-ray photon pulses that would allow the spatiotemporal imaging of events at the atomic scale (~1 Å, ~10 as (atto-second)). The spatial and temporal resolution available from such x-ray pulses would make feasible the observation and ultimately the potential to control ultra-fast, optionally non-linear, atomic processes. With the ability to probe correlated electronic processes within atoms at these timescales, to measure how electrons and nuclei reorganise themselves, either individually within atoms due to external stimulus, during molecular bond making and breaking, or while undergoing subtle catalytic or biological processes, we can begin to unravel how all matter functions at this fundamental level.

The FEL process

FEL operating principle. When electrons enter the undulator,their initially random phases ensure that mostly incoherent radiation is emitted at the resonant radiation wavelength (left). Because the electrons interact collectively with the radiation they emit, small coherent fluctuations in the radiation field grow and simultaneously begin to bunch the electrons at the resonant wavelength. This collective process continues until the electrons are strongly bunched towards the end of the undulator, where the process saturates and the electrons begin to de-bunch.