EXCIMER-LASER ABLATION OF LOW AND HIGH ABSORPTION INDEX POLYMERS

A comparative study of laser ablation of bulk samples of Upilex polyim ide and low density polyethylene, which represent extremes in terms of absorption index at the ArF laser wavelength, is reported. High Speed Shadow photography (HSSP), Probe Beam Deflection (PBD) and Time Resol ved Interferometry (TRI) techniques have been used to provide informat ion about the ablation process. It is shown that HSSP allows the laser generated shock wave and particulate products to be visualised as the y expand away from the ablation site. PBD signals are seen to correlat e well with the HSSP results and allow data to be obtained for an abla tion regime in which no visible plume is observed. The TRI technique g ives complementary, lime-space resolved, information about the nature of the product expansion.