Femtosecond Pulse Light Filament-Assisted Microfabrication of Biodegradable Polylactic Acid (PLA) Material

A novel method for efficient microfabrication in polylactic acid (PLA) using femtosecond pulse generated filaments is presented. Films and micro-woodpile structures of biodegradable plastic are laser engraved, drilled and cut through. The proposed technique is advantageous as the light filament ensures homogeneous energy concentration along the beam propagation axis, thus enables efficient energy delivery without axial translation of the sample. In comparison to sharp light beam focusing this method empowers avoidance of precise focal plane identification. In the experiment polylactic acid sheets and logs were immersed in water so the light filament is formed just above the processable material. The employed laser had a pulse width of 300 fs, average optical power of 5 W, and operated at 1030 nm with 25 kHz pulse repetition rate. This method was compared with traditional microfabrication using tight focusing by an 0.3 NA lens. Grooves, holes and various shapes were manufactured with a micrometer-scale precision as sample structures showing the simple implementation of the proposed novel approach. This method has a potential for finding numerous scientific and practical applications, among them micromechanics, microfluidics, cell growth experiments, and tissue engineering to mention as a few.