Product Code: ICA10_M802

3D-Microstructuring of Sapphire using High Power Fs-Laser Radiation and Selective Etching
Authors:
Maren Hörstmann-Jungemannn, Lehrstuhl Fuer Lasertechnik (LLT), RWTH Aachen University; Aachen Germany
Jens Gottmann, Lehrstuhl Fuer Lasertechnik (LLT), RWTH Aachen University; Aachen Germany
Presented at ICALEO 2010

Micro structuring of sapphire and fused silica is an important market e.g. for microfluidic devices and sensors that combine optical and microfluidic features, freeform microlense systems as well as micromechanical parts. New techniques which enable more material and time efficient processing of sapphire and fused silica are requested.
The In-volume Selective Laser Etching technique ISLE is a two step process for micromachining of transparent materials, e.g. sapphire and fused silica. First the sample is irradiated using fs-laser direct writing with high NA, which induces material modifications within the focal volume by non-linear absorption processes. Subsequently the irradiated volume is removed by wet etching.
The use of high repetition rate fs-lasers, e.g. FCPA lasers with f=0.1-5 MHz, potentially enables a high productivity, but is actually limited by available handling systems which do not allow the combination of high speed, high pressision and high numerical aperture.
To overcome this limitations mentioned above a scanning optics for fs-laser writing with high precision (x= 100-300 nm), high speed (v= 100-300 mm/s) and large numerical aperture (NA=0.4-1.2) is developed.
New results which are achieved with the ISLE method in combination with the developed scanning optics will be shown and discussed. Furthermore first tests of microstructuring with high power-fs-laser radiation (λ= 1030 nm, = 700 fs, f= 20 MHz and P= 400 W) and small numerical apertures (NA= 0.1) are shown.