Fraunhofer diffraction by vibrating optical slits on the surface of a NS-GT cut quartz crystal resonator

When a plane light wave is incident on the n-slit, the Fraunhofer diffraction pattern will be obtained after the n-slit, where n is the number of slits. In this experiment, the n-slit is made on the surface of a NS-GT cut quartz crystal resonator as exciting electrode. The quartz crystal resonator is vibrating at resonant mechanical frequency; the slit width and the distance between slits are vibrated with the resonator. Fraunhofer diffraction patterns contain information on the vibration of the quartz resonator. This phenomenon was named dynamic Fraunhofer diffraction. If a photomultiplier is placed at after the n-slit, a.c. components of the dynamic Fraunhofer diffraction are detected, and distribution patterns of these a.c. components could be taken. This phenomenon can be applied to the dynamic light beam splitter, to evaluate the vibration modes of the resonators, etc.