Optical emission imaging and spectroscopy during femtosecond laser ablation of thin metal films on flexible polymer substrates

Abstract

In this experimental investigation thin metal films (Pd, Cr, and Ti) on flexible polymer substrates are ablated by single femtosecond laser pulses. By use of high speed imaging and spectroscopy the optical emission of ablated material and plasma is recorded temporally and spatially. The ablation plume splits into two components, a fast component with a mainly atomic emission spectrum and a slow component with a broad continuum spectrum. Temporal evolutions of plume components for all three elements are compared and correlations to observations in scanning electron microscopy images of ablation craters are drawn. The results of this study provide insights into the mechanisms of ultrafast laser ablation of thin metal films on flexible polymer substrates.In this experimental investigation thin metal films (Pd, Cr, and Ti) on flexible polymer substrates are ablated by single femtosecond laser pulses. By use of high speed imaging and spectroscopy the optical emission of ablated material and plasma is recorded temporally and spatially. The ablation plume splits into two components, a fast component with a mainly atomic emission spectrum and a slow component with a broad continuum spectrum. Temporal evolutions of plume components for all three elements are compared and correlations to observations in scanning electron microscopy images of ablation craters are drawn. The results of this study provide insights into the mechanisms of ultrafast laser ablation of thin metal films on flexible polymer substrates.