Observations of damage, defects, and structuring in femtosecond laser ablated surfaces

In this work, we specifically focus on the implications of damage present during TriBeam serial sectioning experiments and ways of reducing damage for enhanced data collection speeds. For instance, the choice of scan optics, laser fluences, laser beam wavelength, and polarization will be discussed - as well as their impact on the laser surface modification and subsurface damage. One example of differences in surface profiles after fs-laser ablation is shown in Figure 1. In both cases, a bevel is created at the leading edge of the pedestals where the laser first interacts with the sample, whereas the rest of the ablated surface assumes the shape of a paraboloid. However, differences in scan optics can significantly alter the width and flatness of this cut surface. The incorporation of additional milling operations to reduce surface roughness using glancing-angle focused ion beam milling will also be discussed, as well as its role in improving electron backscatter diffraction (EBSD) yield.