All-in-One Femtosecond Laser Fabrication and Welding of Multilayer Glass Microfluidic Devices

We demonstrate an integrated approach for fabricating multilayer glass microfluidic devices using a single femtosecond laser system for both micromachining and welding. Our custom-designed fiber laser system operates at 1030 nm wavelength with 300 fs pulse duration and repetition rate of 400 kHz – 1 MHz, enabling precise channel fabrication followed by direct glass-glass welding. The system employs a unique spiral scanning strategy for welding, achieving uniform energy deposition and robust bonds while preserving microfluidic features. Fabricated three-layer devices show excellent optical transparency with transmission values comparable to unwelded glass, and the welded interfaces demonstrate complete hermetic sealing necessary for microfluidic applications.