Analysis of the optimum optical incident angle for an imaging acousto-optic tunable filter.

The selection of the incident polar angle is very important in the entire design of the noncollinear acousto-optic tunable filter (AOTF). The authors discussed how the factors, including tuning range of wavelength, the acoustic frequency, the acousto-optic figure of merit, the spectral bandwidth, the spread of filtered beam and the wavelength dependence, influence the selection of the optimum incident polar angle. By an accurate theoretical analysis, a method of selecting the optimum incident angle was presented. The analysis was significant for improving the performance of the imaging AOTF from the visible to the infrared.