Quartz Crystal Microbalances ( QMBs ) for Quantitative Picosecond Laser-Material-Interaction Investigations

In this work Quartz Crystal Microbalances (QMBs) are used to study picosecond laser ablation of magnetron sputtered coatings. The QMBs show a linear characteristic of the sensitivity for layer thickness of different metals up to several microns. Laser pulse resolved measurements of the mass ablated from the metal layer were performed. About 400 ng of chromium was ablated during the first laser pulse while in subsequent pulses less than 220 ng were removed. This is compared with previous findings. The sensitivity for ablation of the QMBs is found to be larger than for deposition, which is explained by the radial sensitivity of the QMBs. Future refinements of the setup and the benefits of the pulse resolved mass loss measurements for laser based methods like calibration free LIBS and LIAS are discussed.