Three-dimensional writing inside silicon using a 2-µm picosecond fiber laser

International audience; Based on the development of a µJ-class Thulium-doped fiber laser operating in the picosecond regime at 1970-nm wavelength, we introduce a solution for three-dimensional (3D) laser writing technologies inside silicon (Si). We reveal that the nonlinear effects preventing from bulk modification in Si with femtosecond pulses persist in the picosecond regime. However, these are strongly reduced which makes possible to derive conditions for a demonstration of data inscription and reading deep into a Si wafer.