Femtosecond laser three-dimensional microstructuring inside photosensitive glasses

Femtosecond laser is used to form three-dimensional (3D) microstructures embedded in Foturan, a photosensitive glass. The microstructures are realized using a three steps process including infrared femtosecond exposure, heating process and etching in an ultrasonic solution of hydrofluoric acid in water. The experiments were carried out using a specially designed ultrafast laser micromachining station, which included a femtosecond laser (Spectra Physics, 110fs, 800nm, 1 mJ/pulse at repetition rate of 1kHz), systems for the delivery, high-precision focusing and spatial-temporal control of the laser beam, and a fully automated and programmed system for the precise target positioning over a prescribed 3D trajectory. Microstructures were compared to those obtained with excimer laser micromachining. Efficiency of the fabrication process will be discussed in terms of the various laser and etching fabrication parameters. This process has some potential interest for the fabrication of 3D microfluidic systems.