"melt" is really the wrong verb. It don't even think one can melt diamond. The correct verb would be "ablate". If one delivers enough energy to a material in a

"melt" is really the wrong verb. It don't even think one can melt diamond. The correct verb would be "ablate". If one delivers enough energy to a material in a small-enough space (eg with short-pulse from a focused laser), the material "vaporizes" down to a certain depth and the process starts all over again at the bottom of the void that was ablated away. You can drill through any film this way.