New laser excitation method for modal analysis of microstructure

• We establish a modal testing system to analyses the dynamic characteristic of microstructures.
• Novel noncontact laser excitation method based on laser–target interaction has been introduced.
• Laser Doppler Vibrometry (LDV) is employed to measure vibration velocity of tested beams.
• Laser excitation capable of excite three modes of beams in once excitation.

A novel impulse laser excitation technique to determine the dynamic response of micro-electro-mechanical systems (MEMS) has been investigated. During the laser excitation experiments, MEMS structures are excited by the wide-band impact force created by the laser–target interaction, and Laser Doppler Vibrometer (LDV) is introduced to measure the vibration velocity of MEMS structures. A distinguishing characteristic of the methodology is that both the excitation and measurement are non-contact, which is especially suitable for the testing of MEMS microstructures that are not easily accessible. This novel excitation method and MEMS modal analysis system are verified by experiments on various cantilever beams. The results show that the laser excitation is capable of exciting the first three modes of cantilevers.