Abstract
A stroboscopic fringe scanning interferometric microscope has been developed to measure small vibrations. In order to set up the microscope, the Fizeau-type Interferometry measuring system is used to obtain stroboscopic interference images of a vibrating surface and an optical isolator is inserted into the interferometer to remove extra interferences from the observed interferograms. The measured interferograms are analyzed by the fringe scanning method. A micro-cantilever for an atomic force microscopy is used as a sample to demonstrate usefulness of the fabricated apparatus. The sample is excited by pressure of sound at a frequency of 13.8kHz. By changing time delay of the laser irradiation, distributions of the vibration at different phases are obtained. The measurement error of the vibration is evaluated to be less than 6nm, which is much less than that of the discrete type. This method is useful for measuring minute vibrations of ultrasonic devices and micro-mechanical systems.
