Three-dimensional silver nanostructure fabrication through multiphoton photoreduction

We present an ultrafast laser technique for 3D direct-writing silver nanostructures embedded in a dielectric. We induce the photoreduction of silver ions through non-linear absorption in a solution doped with silver salts. Nonlinear optical interactions between the chemical precursors and femtosecond pulses limit silver-ion photoreduction processes to a focused volume smaller than that of the diffraction-limit. Our technique creates dielectric-supported silver structures, enabling the nanofabrication of silver patterns with disconnected features in 3D. We obtain sub-300 nm resolution and create 3D arrays of dots, grids and woodpile patterns. We show that the process is scalable and suitable for metamaterial applications.