Together with six industrial partners, Laser Zentrum Hannover (LZH) has developed a picosecond laser system based on fibre lasers. This system, developed as part of the research project called PULSAR (PUlsed Laser System with Adaptive Pulse PaRameters), has achieved excellent micro-machining results for brass and aluminium.
The system fulfils many of the requirements for industrial use. It is especially flexible and adaptable to different settings because the laser oscillator and amplifier are separate. Depending on the material and the desired process results, the repetition frequency and the average output can be adapted to the current process.
A laser diode with a wavelength of 1.03µm and a pulse length of approximately 40ps serves as the pulse source. The pulse repetition rate is flexible, and can be set between 50kHz and 40Mhz. Using a three-step amplifier, the pulse can be amplified from several 10µW to an average output power of 14W. At a repetition rate of 1MHz, a pulse energy of 14µJ is possible.
The fibre-based, picosecond laser system has an excellent beam quality, and is resistant to difficult production environments, such as dust contamination, temperature fluctuation, or mechanical vibrations. Also, very good results in working aluminium or brass have been achieved. Further, the system is small and less expensive than conventional solid-state lasers. There are many fields of applications for this high-power laser; among them marking aluminium, or for making stamps of hard metal (V70) such as for stamping coins.
The PULSAR project is subsidised by the BMBF initiative INLAS (Integrated-optical Components for High-power Laser Sources).