Femtosecond laser bonding of glasses and ion migration in the interface

We report femtosecond laser bonding with strengths of a few MPa and the material mixing during the laser bonding process by using Sm3+- and Cr3+-doped glasses and 180 fs pulses at a repetition rate of 1 kHz from an amplified Ti:sapphire laser at a wavelength of 785 nm. By analyzing fluorescence spectra taken around the interface using a confocal scanning microscope we observed the migration of Sm ions from the upper Sm-doped glass to the lower Cr-doped glass and the reduction from Sm3+ to Sm2+ ions just above the interface for the borate-borate material system. However, in Sm-doped borate-borosilicate, the laser bonding did not produce any reduction and migration of Sm3+ ions.