Ultrashort-pulse laser machining of dielectric materials

There is a strong deviation from the usual tau(1/2) scaling of laser damage fluence for pulses below 10 ps in dielectric materials. This behavior is a result of the transition from a thermally dominated damage mechanism to on e dominated by plasma formation on a time scale too short for significant e nergy transfer to the lattice. This new mechanism of damage (material remov al) is accompanied by a qualitative change in the morphology of the interac tion site and essentially no collateral damage. High precision machining of all dielectrics (oxides, fluorides, explosives, teeth, glasses, ceramics, SiC, etc.) with no thermal shock or distortion of the remaining material by this mechanism is described. (C) 1999 American Institute of Physics. [S002 1-8979(99)01109-3].