Material processing with shaped femtosecond laser pulses

Abstract

Laser material processing of aluminium and some polymers such as polyamide and low-density polyethylene has been performed using femtosecond pulses with different pulse durations. In order to investigate and optimize the ablation process we have developed an experimental setup with spatial light modulator for phase and amplitude modulation of the pulses. Considerable differences in the integrity of areas surrounding cut edges could be found for cuts of aluminum foil made by 70 fs and 230 fs laser ablation. For shorter pulses less damaged area caused by shock waves and less melting of the material have been observed. No debris was attached to the cut edges. The ablation of polymer surfaces has been carried out in nano- and femtosecond regimes. Strong heat transfer into the target, the consequent melting and even bubbling prevent a precise machining of polymers by nanosecond pulses. In addition femtosecond laser ablation allows creation of the holes on the polymer surface with higher precision. Such structures obtained in laser machining experiments can provide the opportunity for designing medical implants with high precision. © 2012 by Walter de Gruyter. Berlin. Boston.