HIGH-TEMPERATURE PULSED PHOTOACOUSTIC STUDIES OF SURFACE-WAVES ON SOLIDS

A noncontact laser system has been designed that employs a pulsed photoacoustic source and an interferometric detector for the measurement of absolute velocity of surface waves. This can be achieved accurately at high temperatures without the need for thermal expansion corrections. Studies have been carried out on polycrystalline aluminum and single-crystal silicon and results have been presented for both at temperatures up to 800 degrees C. The angular dependence of surface wave velocities for propagation in the (001) plane of silicon has also been investigated, and has confirmed the system's 0.5% room temperature accuracy