Laser-induced dendritic structures on PET (polyethylene- terephthalate): the importance of redeposited ablation products

Single-pulse excimer-laser irradiation of poly-ethylene-terephthalate (PET) with fluences around and above the ablation threshold leads to the formation of surface dendrites. The lateral size and the number density of dendrites depend on the laser wavelength and the type and pressure of the ambient atmosphere. The results are discussed on the basis of excimer-laser-induced polymer fragmentation and the redeposition of ablation products.