Impulse laser cutting of diamond accompanied by phase transitions to fullerene-type onions

We studied a process of diamond cutting by a focused pulsed laser beam in an explosion inside solid matter mode (a 100 ns laser beam impulse focused in diamond generates a shock wave). A cavity size created in diamond by the laser impact is described by a conception of a blast cavity formation after explosion inside solid matter. Diamond cutting is also accompanied by a phase transition of diamond to fullerene-type onions composed of 2 to 5 shells. According to a new phase diagram of carbon (which contains a zone of diamond instability in the 55–115 GPa pressure range), the observed phase transition is possible under ~70 GPa pressure and ~2400 K temperature, which indicates pressure and temperature values during laser cutting. The pressure estimated based on the new phase diagram corresponds to the pressure estimated from the known blast cavity formation model. [Display omitted] •We studied a process of diamond cutting by a focused pulsed laser beam in a mode of an explosion inside solid matter.•A cavity size created by the laser impact is described by a conception of a blast cavity formation inside solid matter.•Diamond cutting is accompanied by a phase transition of diamond to fullerene-type onions composed from 2 to 5 shells.•The observed phase transition is possible under pressure ~ 70 GPa and temperature ~ 2400 K.