The design of the noncollinear acousto-optic tunable filter (AOTF) is commonly based on the parallel tangents momentum-matching condition. Previous studies either have used an approximation of the birefringence of the interaction material or have ignored the rotatory property of TeO(2). These approaches would obviously decrease the accuracy of designing an acousto-optic tunable filter (AOTF). We introduce an analysis method of calculating the optimum incident optical angle. Besides, an appropriate optical wedge on the output optical facet is designed to reduce the wavelength dependence of the diffracted beam angle, which is very significant in practical applications of AOTF.

No abstract

The development of the large angular aperture noncollinear acousto-optic tunable filter (AOTF) is based on the parallel tangents momentum-matching condition. In this letter, we have introduced a special double-filtering method that leads to an enhancement of the spectral resolution. And the birefringence together with the rotatory property of the interaction material has been considered to ensure the accuracy of designing an AOTF. The principle and availability of double-filtering are discussed in detail. It is confirmed that double-filtering method is effective to enhance the spectral resolution on the condition of keeping the quality of imaging, which is significant in practical applications of imaging AOTF.

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.

No abstract