Diagnostics and expansion dynamics of the plume produced by laser ablation of a LiYF4 crystal in vacuum.

The expansion in vacuum of the plume generated by the UV ablation of a LiYF4 crystal was analysed as a function of several parameters: distance from the target along the plume axis, laser fluency and angular dislocation with respect to the plume axis. The study was carried out by the optical time of flight technique. Time-resolved signals of the optical emission of the neutral as well as ionised species in the plume were recorded and analysed for different experimental situations. The most probable velocity for each species was calculated and confirmed by the Maxwell-Boltzmann distribution fits of the relative emission temporal profiles. An angular distribution of the ablated species could also be provided. [ABSTRACT FROM AUTHOR]