Characteristic features of a photoacoustic signal due to melting of indium antimonide and of bismuth by nanosecond laser radiation pulses

A study was made of the profile of a photoacoustic signal generated in indium antimonide and in bismuth by nanosecond neodymium laser pulses of intensities sufficient to cause phase transitions in the irradiation zone. The characteristics of the photoacoustic signal associated with the melting and evaporation of the investigated samples were recorded. The behavior of the signal differed from the predictions of a one-dimensional thermal model: the photoacoustic signal was quite wide and it was delayed relative to an evaporation-induced pressure peak.