Generation of moire contours with acousto-optic cells
Blatt, Joel H.
Chang Ho, Huey- Chin
Young, Eddie H.
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Moire contours are seen on a curved surface viewed through a grating when the surface is illuminated with a matched grating. We have been able to replace both the projection and viewing physical gratings with gratings of variable spacing generated in acousto-optic cells, and have been able to observe and record Moire contours. The gratings are generated by amplitude modulating 70 MHz AO cells with a 1 to 10 MHz square wave. The gratings become visible on the curved object by strobing the illuminating laser beam with 50 nsec pulses by means of an AO modulator. Data is given showing the variation in grating spacing with AO modulation frequency. Figures are presented showing the variation of the Moire contour spacing with the AO modulation frequency and with target contour. The results for an angled flat plate target are compared to those in the literature.