F₂-Laserablation

Precise material ablation requires sufficient absorption of the laser radiation. For micromachining of UV-transparent materials with absorption edges in the deep UV (e.g. fused quartz), the F₂ -laser with its emission wavelength at 157 nm is well suited. Using an optical system that is specially adapted to the requirements of F₂-laser radiation, precise structures in quartz, sapphire, fluoride crystals, or UV-transparent polymers (e.g. Teflon) are possible. Micro lenses, relief gratings with sub-micron period, and multilevel diffractive phase elements can be fabricated in this way.

F2-Laser-micro machining system	OCT-scan of a diffractive element recorded in the processing position, step height 128 nm

A module for in-situ surface imaging by optical coherence tomography (OCT) before, during, and after ablative laser processing is integrated into the processing system. This module can be used for work piece adjustment, tilt compensation, focus control, and in-situ profilometry.

Further information:

Jürgen Ihlemann, Malte Schulz-Ruhtenberg, Thomas Fricke-Begemann
Micro patterning of fused silica by ArF- and F2-laser ablation
Journal of Physics: Conference Series 59, 206 (2007)

M. Wiesner, J. Ihlemann, H.H. Müller, E. Lankenau, G. Hüttmann
Optical coherence tomography for process control of laser micro machining
Review of Scientific Instruments 81, 033705 (2010)

M. Wiesner, J. Ihlemann
High resolution patterning of sapphire by F₂-laser ablation
Applied Physics A 103, 51 (2011)