Structural characterization of shock-affected sapphire

The presence of dislocations has been revealed by numerical processing of high-resolution transmission electron microscopy images from the regions affected by a shock wave propagation. The shock wave was triggered by a single 220 fs duration pulse of 30 nJ at an 800 nm wavelength inside sapphire at approximately 10 mu m depth. The shock-amorphised sapphire has a distinct boundary with the crystalline phase, which is not wet etchable even at a dislocation density of similar or equal to 8 x 10(12) cm(-2).