Breaking stress of glass welded with femtosecond laser pulses at high repetition rates

We report on measurements of the breaking stress of glass substrates welded with ultrashort laser pulses. Femtosecond laser pulses at repetition rates in the MHz range are focused at the interface between two substrates, resulting in multiphoton absorption and heat accumulation from successive pulses. This leads to local melting and subsequent resolidification results in the formation of strong bonds at the interface. The achievable breaking stress of this flexible and local bonding process is discussed in detail in dependence of the processing parameters.