Sidelobe reduction of acousto-optic tunable filter by double-filtering

Abstract

For the high acoustic figure of merit of paratellurite (TeO2), it is the most widely used material for acousto-optic tunable filters (AOTFs). The noncollinear AOTF has many applications such as spectral analysis and spectral imaging. We have designed two noncollinear AOTFs which work in VIS range of 550 nm-680 nm. In these two AOTFs, the angle between the propagating direction of the acoustic shear wave and [110] axis is designed to be equal. The two AOTFs are placed fore-and-aft. As the two AOTFs are operated at the same time, a so-called function takes place. By analysis, it can be identified that the double-filtering method can be helpful to improve the performance of the AOTF. In this letter, we have study the function of double-filtering on the sidelobe reduction. By computation, we have given the results which can describe that the sidelobe has been decreased obviously in our studied optical wavelength range. Our study indicates that double-filtering method can be used as a functional method for sidelobe reduction; it is significant for the performance improving of modern AOTF.