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, 170fs, 800nm, 1 mJ/pulse at repetition rate of 1 kHz), 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. Efficiency of the fabrication process is discussed in terms of the various laser and etching fabrication parameters. An example of the fabrication of a 3D microfluidic system for biomedical applications is presented.