Micromachining of hard materials by nano- and picosecond laser radiation: Fundamentals and applications

Abstract

Different metals like gold and tungsten-carbide were microstructured by nano- and picosecond laser radiation with structural dimensions smaller than 20 μm using spot diameters below 10 μm and power densities up to 5×1012 W/cm2. The removal processes of ceramics and metals were investigated using pico- and nanosecond laser radiation produced by diode-pumped Nd:YAG lasers. The threshold fluence for removal and the removal depth per pulse were determinated for 10 nano- and 40 picosecond-pulses.To achieve high accuracy and to reduce material damage in the surrounding area of the removed zone the fundamental interaction mechanisms of nano- and picosecond laser radiation with solids for fluences above the threshold value for laser-induced damage were investigated.The influence of pulse length and laser wavelength (fundamental, SHG) are discussed. To get deeper inside in the interaction of picosecond laser radiation with matter a simple imaging technique was used in pump and probe investigations. By this technique ultrashort processes with a time resolution of 40 ps determined by the duration of pump and probe pulses and a spatial resolution of 1 μm can be investigated.Different metals like gold and tungsten-carbide were microstructured by nano- and picosecond laser radiation with structural dimensions smaller than 20 μm using spot diameters below 10 μm and power densities up to 5×1012 W/cm2. The removal processes of ceramics and metals were investigated using pico- and nanosecond laser radiation produced by diode-pumped Nd:YAG lasers. The threshold fluence for removal and the removal depth per pulse were determinated for 10 nano- and 40 picosecond-pulses.To achieve high accuracy and to reduce material damage in the surrounding area of the removed zone the fundamental interaction mechanisms of nano- and picosecond laser radiation with solids for fluences above the threshold value for laser-induced damage were investigated.The influence of pulse length and laser wavelength (fundamental, SHG) are discussed. To get deeper inside in the interaction of picosecond laser radiation with matter a simple imaging technique was used in pump and probe investigations. By this techniq...