Micromachining of microfluidic channels in glass by microjoule femtosecond laser pulses

Abstract

This study presents overlapping multiple pulse scanning, an alternative approach for forming the microfluidic channels in glass through the interaction of infrared femtosecond laser (FS-laser) irradiation with microjoule-energy pulses. The study employs a scanning-based laser system at a 1035nm wavelength with a pulse duration of 350fs and a repetition rate of 100kHz. In this work, the FS-laser pulses easily induced the dynamics of the optical breakdown process with the laser energy in glass. In addition, a single pulse generates an ablation crater with the irradiation pulse energy of 5@mJ. The study demonstrates that the beam profile, pulse overlap, accumulated fluence, and the number of pulses have the strongest influence on surface morphology to form microfluidic-channels. Herein the surface roughness can be improved to 287nm, and the pulse overlap is 75%. Furthermore, the study analyzes the incubation effect on the number of pulses and the accumulated fluence to confirm the validity of the process model for FS-laser ablation in glass. The technique is useful for prototyping the integrated microfluidic chips that have great potential applications for a lab-on-a-chip.