Laser induced forward transfer aluminum layers: Process investigation by time resolved imaging

Abstract

Laser induced forward transfer of an aluminum thin film on a triazene polymer as a sacrificial layer has been studied with time resolved imaging. Both side- and front-on imaging of the process give a more detailed understanding of the stability of the ejected material during flight. For high fluence ablation (800mJ/cm2) the flyer is stable for 400ns and gets decomposed completely when interacting with the shockwave after 1μs. Material detachments on the edges of the flyer are observed at an early stage of the ablation process (<200ns) which leads to a pixel smaller than its ablation cross section.For low laser fluence (200mJ/cm2) the flyer has the size of the ablation spot and keeps its shape for nearly 1μs. The back pressure of the decomposed triazene polymer bends the flyer towards the direction of flight and indications for folding are observed.