  Understanding how light modifies long-range order is key to improve our
ability to control material functionality on an ultrafast timescale. Transient
spatial heterogeneity has been proposed in many materials, but isolating the
dynamics of different regions experimentally has been challenging. Here we
address this issue and measure the dynamics of orbital order melting in the
layered manganite, La0.5Sr1.5MnO4, and isolate the surface dynamics from the
bulk for the first time. Bulk measurements show orbital order is rapidly
suppressed, but the correlation length surprisingly increases. However, the
surface dynamics, show a stronger suppression and a significant decrease in
correlation length. By isolating the surface changes, we find that light
preferentially melts a less ordered surface and the loss of long-range order is
likely driven by the formation of local and disordered polarons. Melting the
disordered surface effectively increases the average correlation of the bulk
probed volume, resolving the contradictory response. These results show that
surface scattering methods are necessary to understand both surface and bulk
dynamics in heterogeneous materials.
