High speed and high precision fs-laser writing using a scanner with large numerical aperture

J. Gottmann, M. Horstmann-Jungemann, M. Hermans, D. Beckmann
J. Laser Micro / Nanoeng. Vol. 4, No. 3, pp. 192-196

FCPA µJewel D-1000

Currently available high speed scanning systems based on galvo mirrors are equipped with objectives with small numerical apertures (NA < 0.2) which are not sufficient for most of the in-volume micro structuring processes. Whereas high precision air bearing translation stages are used with microscope objectives the speed is limited to approximately 100 mm/s. In order to overcome these limitations we integrated a galvo scanner into a system with large maximum scanning velocity (50 - 400 mm/s), large numerical aperture (NA = 0.4 - 1.2), small focus size (0.6 - 2.2 µm), high precision (100 - 400 nm) and computer controlled pre-compensation of spherical aberrations for in-volume focusing. Furthermore, we combined the scanning system with a computer controlled three axis translation stage to process large flat work pieces such as wafers up to 2 mm in thickness. As application of the scanner high speed direct writing of waveguides, markings, nano structures inside transparent materials as well as the high speed fabrication of 3D micro structures by in-volume selective laser etching are demonstrated.

View Full Paper