Colinear thin-film acousto-optic scanner

An analysis is given of the scattering of light from an asymmetric slab waveguide into the substrate when this is caused by a surface acoustic wave of the Rayleigh type, both the effects of the photoelastic index fluctuations and the elastic displacements are considered. Design criteria for efficient scattering are established and numerical results are given. An experimental acousto-optic scanner consisting of a sputtered glass film on a quartz substrate is demonstrated with a resolution of 46 spots obtained with only a 10 MHz bandwidth. A possible implementation as a microscanning device is discussed.