A Study of the Acoustic-Optic Effect in Nematics.
Final rept. 1 Sep 78-31 Dec 80,
HAWAII UNIV HONOLULU DEPT OF PHYSICS AND ASTRONOMY
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The program of this contract has been to study the acousto-optic effect which occurs in nematic liquid crystals when excited by acoustic waves. Both theory and practical application are presented. Hydrodynamic equations were solved which govern the streaming and obtained a solution for the magnitude of the fluid speed and flow pattern for a small disc-shaped liquid crystal. A sample, doped with grains, was used to test the solution experimentally. A series of cells were constructed and tested which, in fact, showed that an acoustic wavefront pattern can be visualized with this technique. During the second year of the contract we developed and tested a mathematical model which prescribes how a cell should be constructed in terms of the densities of the cell walls, liquid crystal, and surrounding fluids the thickness of the cell walls and liquid crystal layer the acoustic speeds in cell wall shear and longitudinal, liquid crystal, and surrounding fluids acoustic frequency and the incident acoustic bean angle. Cells were also constructed and tested in which an electric field could be applied simultaneously with the acoustic wave in such a way that the sensitivity of the cell to the acoustic field could be adjusted.
- Physical Chemistry