Modifications to a high-precision direct laser writing setup to improve its laser microfabrication

Abstract

Two-photon-absorption (2PA) techniques enables the possibility to create extremely fine structures in photosensitive materials. For direct laser writing as micro- or nanofabrication a laser system can be combined with highly precise positioning systems. These are mostly limited by a few hundreds micrometer positioning range with applications based on piezoelectric stages or even just relatively few tens micrometer positioning range with applications based on galvanometer scanners. Although these techniques are precise, but stitching methods are required for larger fabrication areas. Therefore, a setup consisting of a femtosecond laser for 2PA and a nanopositioning and nanomeasuring machine (NMM-1) was developed for high precision laser writing on lager surfaces. Further developments of the system should enable a significant improvement in high-precision and stitching free direct laser writing. In order to combine the the femtosecond laser and the NMM-1 into a functional unit, to write complex structures with highest accuracy and homogeneity, further improvements like a beam expansion for a better use of the numerical aperture of the objective and a new femtosecond laser with a integrated power measurement are realized. This showed improvements in line width for nano strucuring. Advantages and disadvantages as well as further developments of the NMM-1 system will be discussed related to current developments in the laser beam and nanopositioning system optimization.