Multi-scale laser direct writing of conductive metal microstructures using a 405-nm blue laser

A multi-scale direct writing method for metal microstructures is proposed and demonstrated. In this study, metal structures were created in a gelatin matrix containing silver nitrate by photoreduction using a 405-nm blue laser. The influence of concentrations of materials in the sample solution was evaluated by measuring the conductivity of the fabricated microstructures. The fabrication line width could be controlled by changing the laser scanning speed. A network structure was also observed, which possibly helps in increasing the microstructure's conductivity. Finally, we demonstrated multi-scale drawing by using objective lenses with different numerical apertures. Our method can result in new possibilities for conductive metal direct writing.