There are two mechanisms to explain laser ablation process: Classical beam-matter interaction mechanism for micro- and nano-second pulse laser ablation and two temperature mechanism for pico-and femto-second pulse laser ablation.
The two process can be explained by the following figure:
The source of the information is “Karl-Heinz Leitz et al., Physics Procedia 12 (2011) 230–238“. More details can be obtained there.