Production of microstructures in wide-band-gap and organic materials using pulsed laser ablation at 157 nm wavelength

New results on three-dimensional microstructuring of fused silica, sapphire, calcium fluoride, magnesium fluoride, and PTFE using pulsed laser ablation at 157 nm wavelength are presented. A largely automated high-precision fluorine laser micromachining station was used for the investigations. In some fundamental investigations, threshold fluences of 0.9 J/cm(2) for fused silica, 0.6 J/cm(2) for sapphire, 1.7 J/cm(2) for calcium fluoride, and of 0.05 J/cm(2) for PTFE have been determined. The ablation rates at 3 J/cm(2) fluence were 60 to 100 nm/pulse for the inorganic insulators and 450 nm/pulse for PTFE. In the second part of the paper, it is shown that on the basis of the knowledge of the ablation rates and the laser beam parameters, bores of a few A mu m size and complex 3D microstructures with a variety of geometries can be produced in the surface of these materials. Thereby, no cracking occurs if proper parameters are used.