The core idea behind this technology is nonlinear absorption. The extremely high intensity achieved in the focal volume of a focussed femtosecond laser pulse induces nonlinear phenomena such as multiphoton or tunneling ionization and avalanche ionization, thus producing a very localized deposit of energy in the volume of the material. Suitable motion of the sample can produce 3D modifications.
The basic devices that can be fabricated by this technology are optical waveguides and microfluidic channels (the latter requires a subsequent etching step). Further processing tasks that can be performed by this technology are: welding, cutting, surface texturing, etc. Combination of all these capabilities result extremely powerful in producing complex photonic and optofluidic devices that are also characterized in our labs.