A versatile heterodyne interferometer for vibration measurement and analysis of micro-structures

A versatile heterodyne interferometer for vibration measurements of microstructures is presented. The interferometer is able to measure absolute amplitude and phase from out-of-plane vibration fields. Its measurement range covers the vibration frequency up to 12 GHz with the current setup, and amplitude up to several hundred nanometers by combining the Bessel functions. To demonstrate the capabilities of the setup, measurements of A(0) lamb wave mode and S-1 lamb wave mode of a piezoelectric micromachined ultrasound transducer were implemented. The results show the versatility of the setup for vibration measurements of microstructures. (C) 2020 The Japan Society of Applied Physics