Aimed at thin film’s Young’s modulus measurement method by laser generated ultrasonic

a novel light deflection detecting method is proposed.This technology adopts differential detecting method to restrain common model noises.Confocal structure is used to enhance the system’s stability and to reduce influence of disturbances of environment.Its working principle is explained.This method is applied in film’s Young’s modulus measuring system by laser generated surface acoustic wave（SAW）.An experimental dispersion curve of SAW propagation in a standard sample is obtained.Good fitting result of this experimental dispersion curve with its theoretical calculation curve proves this detecting method’s practicability.