Start Date

10-5-2017 11:00 AM

End Date

10-5-2017 1:00 PM

Subjects

Scanning probe microscopy, Finite element method, Acoustic microscopy

Description

Whispering Gallery Acoustic Sensing (WGAS) has been studied by Department of Physics at Portland State University as a mean of controlling sample to probe distance in tuning-folk-based scanning probe microscopy (TF-SPM). WGAS uses the microscope frame as a resonance acoustic cavity. The setup shows high potential because of high-quality factor nature of acoustic cavity as well as using mechanical motions of the TF itself instead of electrical signals. However, the analytic solution of the eigenfrequencies of the current microscope frame is very complex due to the asymmetric geometry. The purpose of this study is to use finite element method to simulate the frequency response of the acoustic cavity. We specifically get the response around 32kHz which is also the operate frequency of current WGAS system. Our simulation result is verified by comparing with experiment result of a much simpler symmetric cavity. The study is not only on investigating WGAS working principle but also to find ways to improve the signal to noise ratio by finding sensor position and modifying the frame geometry.

Persistent Identifier

http://archives.pdx.edu/ds/psu/20088

Included in

Physics Commons

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May 10th, 11:00 AM May 10th, 1:00 PM

Finite Element Method Analysis of Resonant Cavity for Whispering Gallery Acoustic Sensing Microscopy

Whispering Gallery Acoustic Sensing (WGAS) has been studied by Department of Physics at Portland State University as a mean of controlling sample to probe distance in tuning-folk-based scanning probe microscopy (TF-SPM). WGAS uses the microscope frame as a resonance acoustic cavity. The setup shows high potential because of high-quality factor nature of acoustic cavity as well as using mechanical motions of the TF itself instead of electrical signals. However, the analytic solution of the eigenfrequencies of the current microscope frame is very complex due to the asymmetric geometry. The purpose of this study is to use finite element method to simulate the frequency response of the acoustic cavity. We specifically get the response around 32kHz which is also the operate frequency of current WGAS system. Our simulation result is verified by comparing with experiment result of a much simpler symmetric cavity. The study is not only on investigating WGAS working principle but also to find ways to improve the signal to noise ratio by finding sensor position and modifying the frame geometry.