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Dynamics of laser-induced cracking in glasses at a picosecond time scale

The interaction of picosecond pulsed laser radiation with BK7 glass has been investigated. Focusing laser pulses with 40 picosecond pulse duration in BK7 glass leads to plasma and crack formation by evaporation and induced stress. The plasma dynamics is measured by pump and probe techniques using the speckle method with a time resolution of 50 Ps and a spatial resolution of 1 ?m. Plasma transmission and refractive index changes are measured during and after irradiation on a picosecond time-scale. The plasma emission is investigated on the time scale of 10 ps -500 ns by high-speed photography and by time-resolved spectroscopy. The morphology of the cracks is evaluated using Nomarski microscopy.