  Laser-driven compact particle accelerators can provide ultrashort pulses of
broadband X-rays, well suited for undertaking X-ray absorption spectroscopy
measurements on a femtosecond timescale. Here the Extended X-ray Absorption
Fine Structure (EXAFS) features of the K-edge of a copper sample have been
observed over a 250 eV window in a single shot using a laser wakefield
accelerator, providing information on both the electronic and ionic structure
simultaneously. This unique capability will allow the investigation of
ultrafast processes, and in particular, probing high-energy-density matter and
physics far-from-equilibrium where the sample refresh rate is slow and shot
number is limited. For example, states that replicate the tremendous pressures
and temperatures of planetary bodies or the conditions inside nuclear fusion
reactions. Using high-power lasers to pump these samples also has the advantage
of being inherently synchronised to the laser-driven X-ray probe. A perspective
on the additional strengths of a laboratory-based ultrafast X-ray absorption
source is presented.
