"In tapping mode atomic force microscopy, surface features are measured indirectly via the amplitude of the tapping cantilever. A change in surface profile is detectable only if it results in an amplitude change that is significant enough to be measured by the optics. Previous works have focused on improving sensitivity through the system's Q-factor, either by changing physical cantilever properties or using feedback control, but those approaches undesirably slow down the dynamic response. In this work we take a novel approach to sensitivity amplification by reshaping the tapping trajectory. By shaping the trajectory so that the probe spends a greater portion of each period close to the sample, where nonlinear forces is strongest, and the amplitude sensitivity can be altered. A trajectory using two harmonics is considered and standard feed forward control techniques are employed to generate the desired cantilever drive signal. Simulation and experimental results are included and benchmarked against previous literature using standard methods. The results demonstrate that measurement sensitivity can be improved by a significant amount"--Abstract, page iii.
Bristow, Douglas A.
Landers, Robert G.
Stutts, Daniel S.
Sarangapani, Jagannathan, 1965-
Mechanical and Aerospace Engineering
M.S. in Mechanical Engineering
Missouri University of Science and Technology
x, 110 pages
© 2011 Santosh Ramaiah Kodandarama, All rights reserved.
Thesis - Open Access
Library of Congress Subject Headings
Atomic force microscopy
Image processing -- Mathematical models
Surfaces (Technology) -- Analysis
Print OCLC #
Electronic OCLC #
Link to Catalog Recordhttp://laurel.lso.missouri.edu/record=b10814952~S5
Kodandarama, Santosh R., "Bi-harmonic atomic force microscopy" (2011). Masters Theses. 7364.