Depletion of the pump pulse in second harmonic generation (SHG) and its back-regeneration from the second harmonic pulse is a well known process in nonlinear optics. Nevertheless how the pump pulse reshapes as a three-dimensional object in space and time has never been investigated. In this work we apply a three-dimensional mapping technique to record this transformation and we experimentally show the formation of a hollow as well as more complex layered spatiotemporal structures of the fundamental pump pulse in different regimes. The results are compared with numerical simulations
