title: A diffraction-based optical method for the detection of in-plane motion of lamb waves.
abstract: This paper describes a laser optical technique that allows the detection of in-plane motion of Lamb waves. This interference-based laser optical technique includes a tiny square indentation with a width of about 30 micron on the sample surface and a relatively simple optical arrangement. The current technique is applied for the detection of in-plane motions of Lamb waves propagating in a 70-micron thick brass plate. Measurement of So mode dominated by in-plane motion in the low fd (frequency times thickness) regime is successfully demonstrated with the current technique. With the indentation replaced by a microreflector in a microelectromechanical (MEMS) structure, this technique is applicable for the detection of in-plane motion in MEMS structures.
authors.affiliation: Department of Mechanical Engineering, Chang Gung University, Kwei-Shan, Taoyuan, Taiwan. yang@mail.cgu.edu.tw
authors.forename: Che-Hua
authors.initials: CH
authors.lastname: Yang
authors.forename: Yua-Ching
authors.initials: YC
authors.lastname: Tsai