Ion acceleration by lasers is one of the most important innovations in
laser-plasma research in recent years. A mechanism that has gained great
attention due to the remarkable properties of the accelerated beam is
laser acceleration of protons from the rear surface of solid targets. A
striking prediction is that these protons are capable of generating images
of micro-structures present on this surface. These images might be useful
to measure properties of the accelerated beam. In this article, we address
the physics of the generation of images of surface structures imprinted
into the target back surface with laser-accelerated protons.
