Optoacoustical investigation of the melting of indium by a laser pulse under a confined surface

An investigation was made of laser-induced face transitions of metals under confined surface conditions. The dynamics of the melting of indium was investigated by direct recording of a thermo-optically excited pressure pulse. The steep pressure rise observed when the absorbed energy exceeded the melting threshold was related to the volume expansion of the melt. The proposed method could be used to investigate phase diagrams of substances right up to their critical points.