Influence of Target Cavity Formation on the Emission Spectra of Nanosecond Laser Ablation Plasmas

Optical emission spectroscopy as well time-of-flight (TOF) measurements were performed in the diagnostics of nanosecond laser produced plasmas. The target is rotated during pulsed ablation at 5 GW/cm2, where optical along, perpendicular to axis. Parallel axis, continuum radiation intensity increases up 6000 pulses, and line intensities from C I II increase for with number pulses. Perpendicular decrease observed. TOF resulted carbon cluster ions detection Cn+, n ≥ 2, peak shift 4 µs towards later times observed after 10000 pulses ablation. Charge collection experiments showed approximately 80 percent energy loss shots. Collision-induced recombination mechanisms suggested causes decrease.