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Acoustic-Excitation Optical Coherence Vibrometer for Real-Time Microstructure Vibration Measurement and Modal Analysis

An acoustic-excitation optical coherence vibrometer (AE-OCV) is proposed for noncontact microstructure vibration measurement and modal analysis. The vibration dynamic parameters of the microstructure can be captured with a subnanometer displacement resolution by the proposed AE-OCV using spectral wavelength calibration algorithm and spectral center correction method. The natural frequency of the microstructure could also be obtained by the developed noncontact AE-OCV system using the swept-frequency acoustic excitation method. Furthermore, a home-made spectrometer based on a high-speed linear camera could provide the system with a frequency measurement range of 0–50 kHz. The developed AE-OCV has an excellent performance in microstructures vibration measurement and modal analysis, especially for high-frequency and nanoscale vibration measurements. It is of great significance to the design of the microelectromechanical system (MEMS), such as the noncontact dynamic measurement of cantilevered beams in atomic force microscopy.