A spectroscopic study of plasmas produced by laser ablation of hollow aluminium targets

摘要

In this paper we report the study of plasmas generated when the laser beam hits a target surface in the middle of a hole through the target, the diameter of the hole being slightly smaller than the laser beam's waist. The hole's axis coincides with the laser beam's axis. In such a case two plasma clouds are observed: one expands from the front hole opening towards the laser, the other from the back side of the target in the opposite direction. The experiments indicate that the plasma in front of the target is similar in appearance to the plasma generated by ablation of a planar surface. On the other hand, the plasma behind the target is significantly less dense and is also much colder than the corresponding plasma in front of the target. [References: 14]