Method and apparatus for measuring the birefringence parameters of a material by time measuring.

摘要

The method and device is intended for the determination of the acoustic birefringence parameters theta i and phi i of a locally parallel- sided plate of given thickness e. A linearly polarized sound wave is produced along a reference direction Ox1, Oy1 and is directed towards the input surface of the plate (LA). The reflected pulses produced by the incident pulses in the above-mentioned reference directions are detected and measured with respect to a reference time. The operation is repeated for at least one other reference direction different from the first and all the operations are repeated for several different sound wave frequencies, thus obtaining a set of values for the time delays of the echoes produced. The birefringence parameters theta i, phi i are obtained by solving the combinations of equations relating these parameters for different emission frequencies fk. Application to the study of materials. <IMAGE>