Plasma evolution of carbon nanotube paper induced by double-pulse of nanosecond laser irradiation

This study experimentally investigates the spatiotemporal evolution characteristics of plasma and C₂ molecules generated from carbon nanotube paper under single-pulse and double-pulse laser irradiation (Δt = 10 ns). The time-resolved images show that under single-pulse excitation, surface plasma and spatially-distributed plasma in the ambient space exhibit distinct intensity variation trends, with C₂ molecules primarily originating from ablation at the sample surface. In the double-pulse case, the pulse delay enhances the self-focusing effect of the delayed plasma and reduces material ejection, resulting in lower plasma emission intensity and smaller emission area compared to the single-pulse case. These findings reveal the regulatory effect on plasma and material ejection behavior by double-pulse.