Picosecond laser pulses are used to micro-machine virtually any material with highest precision and minimal thermal impact. Best quality has been demonstrated at low fluence removal near ablation threshold with pulse energies of a few µJ. Economical throughput is achieved by very high pulse repetition rates of more than 500kHz. Picosecond laser systems broke into the industrial market more than 2 years ago. However, picosecond laser micro-machining is not yet a mature technology because wide and practical experience of micro-machining with picosecond pulses is limited thus far. In order to achieve outstanding quality and maximum throughput in laser micro-machining with picosecond lasers the proper selection of laser parameters is important and the proper process parameters are also critical.
This article reports experimental results related to the influence of pulse trains for ablation efficiency and quality and shows examples of micro-machining using different laser wavelengths. An outlook for developments in these areas is presented.