Structuring of functional thin films and surfaces with picosecond-pulsed lasers

Abstract

During the recent few years picosecond lasers have been proved as a reliable tool for microfabrication of diverse materials. We present results of our research on structuring of thin films and surfaces using the direct laser writing and the laser beam interference ablation techniques. The processes of micro-pattering were developed for metallic, dielectric films as well as complex multi-layer structures of thin-film solar cells as a way to manufacture frequency-selective surfaces, fine optical components and integrated series interconnects for photovoltaics. Technologies of nano-structuring of surfaces of advanced technical materials such as tungsten carbide were developed using picosecond lasers as well. Experimental work was supported by modeling and simulation of energy coupling and dissipation inside the layers. Selectiveness of the ablation process is defined by optical and mechanical properties of the materials, and selection of the laser wavelength facilitated control of the structuring process. Implementation of the technologies required fine adjustment of spatial distribution of laser irradiation, therefore both techniques are benefiting from shaping the laser beam with diffractive optical elements. Utilization of the whole laser energy included beam splitting and multi-beam processing.