Ultrafast laser structuring of hard and soft materials

Femtosecond laser material processing is a versatile tool for precise machining of well-defined, micron and sub-micron features. We present studies of the interaction of 800 nm femtosecond laser pulses with BK-7 glass, PDMS, fused silica, diamond films, and tungsten-based hard metals. The laser pulse energy varied between 0.2 µJ to 2.8 µJ and materials were exposed to single pulses and trains of multiple pulses with repetition rates up to 250 kHz. Ablated areas were studied with scanning electron microscopy (SEM) and replication techniques. The results include laser machining of microstructures for fluidic and photonic device applications. The dependences of feature size and quality on laser pulse energy and number of pulses are discussed. We observed different ablation rates in composite materials, giving rise to a possibility of preferential structuring of various sites. Our experimental results show a strong correlation between ablation rates and material properties.