Welding of glass/glass and Si/glass using ultrashort laser pulses

In this paper, novel fusion welding procedures using ultrashort laser pulses (USLP) to join glass-to-glass and Si-to-glass, which are useful for electronics, MEMS, biomedical and so on, are overviewed. When USLP is tightly focused into bulk glass, plasma is produced by nonlinear absorption process due to multiphoton ionization followed by avalanche ionization to provide embedded molten pool in bulk glass. The dual-structure consisting of the outer and inner structures is produced, which correspond to molten region and the laser absorption region (Fig. 1ab). Nonlinear absorptivity is evaluated at uncertainty less than ±3% and the distribution of absorbed laser intensity w(z) based on thermal conduction model [2].