Spectral resolution enhancement of acousto-optic tunable filter by double-filtering

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.