MEASURING METHOD OF PROPAGATION SPEED OF ELASTIC WAVE IN SURFACE OF CRYSTAL

摘要

PURPOSE:To enable measurement of a propagation speed in an arbitrary place or area on the surface of an elastic body crystal by a method wherein an elastic wave is generated by exciting the crystal and the displacement of a strain of the surface of the crystal for a prescribed time is detected by a holographic interference method. CONSTITUTION:A transducer 2 which impresses an electric field of a prescribed frequency on an electrode formed on the surface of a crystal by mask evaporation gives a strain to the crystal 1 to be measured and thereby makes it generate an elastic wave. A laser light outputted from a laser 3 and reflected by a half mirror 5 is reflected further by a reflector 6 and applied onto the surface of the crystal 1, and it turns to be a reflected light therefrom and is led to a holographic processing device 8. Meanwhile, the laser light transmitted through the half mirror 5 is reflected by a reflector 7 and led directly to the holographic processing device 8. In the holographic processing device 8, an instantaneous hologram representing the state in some instant of the surface of the crystal 1 to be measured is formed by the interference of these two lights led through different courses.