Enhanced drilling using a dual-pulse Nd : YAG laser

A new method for improving the efficiency of laser drilling has been develo ped. Two synchronized free-running laser pulses from a tandem-head Nd:YAG l aser are capable of drilling through 1/8-in-thick stainless-steel targets a t a standoff distance of Im without gas-assist. The combination of a high-e nergy laser pulse for melting with a properly tailored high-intensity laser pulse for liquid expulsion results in the efficient drilling of metal targ ets. We argue that the improvement in drilling is due to the recoil pressur e generated by rapid evaporation of the molten material by the second laser pulse.