  A pump-probe dark-field X-ray microscopy (DFXM) experiment was carried out at
the Advanced Photon Source (APS) with nanosecond drive laser pulses and hybrid
mode X-ray probe pulses. We observe a thermal decay due to laser-induced heat
diffusion in a Germanium single crystal which matches the theoretical
prediction. The single pulse DFXM imaging in combination with the laser-pump
X-ray probe method could reveal thermal strain formation and propagation of the
acoustic wave "on-the-fly" generated by a laser-induced lattice deformation.
This will open a new avenue of materials research on laser-induced dynamic
phenomena in solids at sub-nanosecond time scales.
