Sound speed resolved by photoacoustic technique

in this work a new method for measuring the speed of sound in materials is reported. this method uses the photoacoustic effect, which is the generation of sound waves by pulsed optical radiation incident on a material sample. the sound waves generated on the surface of the sample travel through the material and are detected with two piezoelectric sensors separated by a known distance. an appropriate processing of the photoacoustic signal permits the separation of the information of the generated longitudinal waves, of their reflections, as well as of other types of waves generated (shear, surface, etc). the advantages and disadvantages, of this method are discussed in comparison with standard methods.