136. surface acoustic wave (saw) guiding and steering on lithium niobate

Department: Mechanical & Aerospace Engineering
Faculty Advisor(s): James R. Friend

Primary Student
Name: Jiyang Mei
Email: j1mei@ucsd.edu
Phone: 312-509-1118
Grad Year: 2019

Abstract
Lateral diffraction of waves is a major constraint in current surface acoustic wave (SAW) devices inevitably resulting in energy dissipation along certain direction. Though one may seek to minimize its effects by the choice of a low diffraction propagation direction, there are situations in which fluid or particle manipulation at disparate locations in a micro device are expected. The difficulties in controlling the direction of wave propagation make these applications inefficient as well. However, these limitations may both be overcome by the use of waveguides for such surface waves, where the term waveguide implies a geometrical structure, such as, a thin conducting film. The concept of thin fi lm waveguide was fi rst introduced by White and Seidel. They suggested that thin films of finite width deposited on an isotropic substrate can be used to guide elastic surface waves in the substrate. The metal strip short circuits the electric field associated with the piezoelectric surface wave and, as a result, produces a slight reduction in the velocity of that wave under the strip. Although the guiding mechanism has so far been widely understood, the applications are generally associated with long delay lines and structural health monitoring, while that in the context of acoustofuluidics is still lacking. With the entrance of waveguide structure deposited on lithium niobate, the energy flow propagated on it was calculated as the integral of squared amplitude over the waveguide width. The result shows more than 25 percent of the energy deviated away from the original direction, indicating its ability of turning wave along the guiding layer to some extent. This poster will demonstrate that the introduction of waveguide overcomes diffraction and expands the ability to transmit waves from one dimensional to two, which reveals the potential of manipulation waves for acoustofluidic applications.

Industry Application Area(s)
Control Systems | Life Sciences/Medical Devices & Instruments

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