Defect formation in glass welding by means of ultra short laser pulses

Many applications require a joining of several glass components. However, the established processes for glass joining have certain disadvantages. By contrast, laser fusion welding by ultrafast lasers exhibits in principle excellent versatility, if the nonlinear interaction is localized enough so that plasma induced stresses can be tolerated and the temperature is high enough to melt the glass adjacent to the focal spot. However, defect generation during welding was observed for a broad range of welding conditions. This paper reports the observed defects and analyzes their origins.