Fig. 6
From: The route to microstructures with optical quality glass surfaces by fs laser ablation
Post treatment after laser ablation including chemical cleaning. (A) Cross sectioned view of the evaluated complex system design with corresponding cross sectional line profile, that was used for roughness measurements. The roughness after 14 layers of 50 μm height ablation equals Sq = 1.73 μm. (B) SEM images (upper row) and DIC images (lower row) of laser structured parameter slots surfaces after subsequent chemical treatment steps. The first image shows the surface of the glass right after the laser ablation. For the second image, glass was cleaned in an ultrasonic bath filled with ethanol for 15 min to wash away the debris. For the following images, the glass was dipped in a glass-etching solution for 30 s, 60 s and 90 s resulting in typical surface pits. The scale bar is 5 μm for SEM and 200 μm for DIC images. (C) The roughness values (Str) on glass surfaces measured after the individual glass treatment steps. For a surface with a dominant lay, the Str parameter tends towards 0, whereas a spatially isotropic texture results in a Str close to 1. The progressing chemical treatments can selectively dissolve or wash away certain components of the glass, leading to specific surface features that can either increase or decrease surface roughness, depending on the treatment used.
