Dissimilar Material Welding with High Pulse Repetition Rate Femtosecond Fiber Laser

Material joining techniques (especially for dissimilar and novel material joining) have become increasingly important in industrial processes in a wide variety of areas. Major technical challenges are:(i) thermal expansion mismatch, (ii) reduced temperature and load ranges, and (iii) increased directionality. These often impact the welding strength and reliability. A high power and high energy femtosecond fiber laser welding technique will be developed for joining dissimilar materials with least thermal impact and residual stress. In addition to the dissimilar welding in automobile industry, this project can be immediately adopted by other material processing. This includes (1) Photonic device fabrications, such as waveguide, coupler, WDM, modulator, and switching; (2) all types of metal processing such as welding, cutting, annealing, and drilling; (3) semiconductor and microelectronics manufacturing such as lithography, inspection, control, defect analysis and repair, and via drilling; (4) marking of all materials including plastic, metals, and silicon; (5) other materials processing such as rapid prototyping, desk top manufacturing, micromachining, photofinishing, embossed holograms, and grating manufacturing.