Accurate design of a noncollinear acousto-optic tunable filter.

The analysis of a noncollinear acousto-optic tunable filter commonly found in the literature is based on an approximation for the birefringence of the interaction material. It is demonstrated that this approximation leads to a significant error in calculating the optimum incident angle for a device, which can seriously degrade its performance if a fixed output beam angle is required. An alternative, exact analysis is presented and compared with experimental results.