SCHOOL OF MECHANICAL ENGINEERING SEMINAR Monday, April 29, 2013 at 15:00 Wolfson Building of Mechanical Engineering, Room 206
Mass sensors and parametric excitation by fringing fields
in thin film micro-resonators
Dr. Yoav Linzon
Division of Physics and Optical Engineering, Ort Braude College of Engineering, Israel
We perform in-situ sensing of volatile droplet and spray liquid mass using plate-like micro-resonator plates with low tensile stress, where robust and reusable operation was attained over harsh conditions and multiple cycles. A home-built electro-optical motion sensing system in ambient conditions has been used. The bimorphic effects on the resonant frequency of altered mass loading, elasticity and strain are compared, and the latter are found to be negligible in the presence of non-viscous liquids deposited on top of the devices. In resonant mode, the loaded mass is estimated from measured resonant frequency shifts and interpreted from simple (uniformly deposited film) model. A minimum sub-ng detectable mass has been estimated, suggesting the potential for fast and reusable sensing capabilities of volatile liquids under harsh operation conditions. We also describe very efficient parametric drive in electrostatically excited single-layer microresonators, which can be employed in future surface material sensors.