Flexible and rapid fabrication of silver microheaters with spatial-modulated multifoci by femtosecond laser multiphoton reduction

In this Letter, parallel writing of silver microwire (AgMW) arrays based on femtosecond laser multiphoton reduction (MPR) is realized by modulating a femtosecond laser beam into a multifoci pattern with a spatial light modulator (SLM). Arbitrarily distributed multifoci are generated with predesigned holograms loaded on a SLM for MPR. The experimental parameters for the desired fabrication of AgMWs with multifoci are systematically investigated and optimized. On this basis, different AgMW patterns are dynamically and simultaneously fabricated by loading different holograms onto a high-frequency refreshed SLM in sequence. The quantity and distribution of multifoci can be controlled dynamically by the SLM in the fabrication process, and even the intensity of individual focus is dynamically modulated by the control of the gray level of holograms. Finally, the potential application of this flexible and rapid AgMW fabrication method in microheater fabrication is demonstrated. The microheaters exhibit a controllable temperature gradient after energized.