The basic principle of laser ablation is that laser irradiation of a certain wavelength introduces so much energy into the resist material which is modified for ablation that the resist polymer is destroyed and then vaporizes as low molecular weight fragments. This process can be promoted by introducing suitable dye additives. The result is transparent structures (ablated surfaces) in the otherwise opaque surface.
Within the scope of the Photoenco project (June 2016 – May 2019), protective resist samples with dyes were created. Layers of these samples were irradiated with a 532 nm laser of different intensity. The figure demonstrates that with increasing laser power, the layer is completely ablated.
Figure: Lines written with 532-nm laser into PMMA and novolac layers
Resist samples for different laser wavelengths can be manufactured with appropriate dyes.