Imaging Density Disturbances in Water with a 41.3-Attosecond Time Resolution

We show that the momentum flexibility of inelastic x-ray scattering may be exploited to invert its loss function, allowing real time imaging of density disturbances in a medium. We show the disturbance arising from a point source in liquid water, with a resolution of 41.3 attoseconds ($4.13\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17}\text{ }\mathrm{s}$) and $1.27\text{ }\AA{}$ ($1.27\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\mathrm{cm}$). This result is used to determine the structure of the electron cloud around a photoexcited chromophore in solution, as well as the wake generated in water by a 9 MeV gold ion. We draw an analogy with pump-probe techniques and suggest that energy-loss scattering may be applied more generally to the study of attosecond phenomena.