Analysis of newly designed phased array birefringent acousto-optic devices

A normalized expression for the frequency character of the reinforce direction of phased array transducers is established, and its characteristic is discussed. It is found that good beam steering results can be obtained only if the frequency characteristic of the effective acoustic direction, has negative slope and positive curvature. For many cases, this can be obtained only by taking the fast mode as the incident light. For cases where the curvature of the frequency characteristic of the effective acoustic direction nearly equals twice the absolute value of its slope, the beam steering results are excellent. New designs of phased array TeO₂ and lithium niobate devices are implemented to illustrate these ideas. These new designs of phased array birefringent devices best solve the contradictory requirements imposed by a high diffraction efficiency and a large Bragg bandwidth