Nanosecond pulsed laser ablation of a transparent polyethylene film moving around the beam waist

A nanosecond pulsed laser that can induce the breakdown of air in the focal region was used to irradiate a transparent PE film having a thickness of 0.6 mm. A high-speed Schlieren optics system was used to record the ablation process. The results indicate that the irradiation process was sensitive to the specific positions of the PE film. When the front surface of the PE film was positioned slightly away from the beam waist, the initiated plasma, the generated plume and the crater on the surface of PE film differed significantly with the position of PE film in relation to the beam waist.