A.S. Machihin, V.E. Pozhar

One of modern tendencies in spectroscopy is imaging spectrometers development for simultaneous research of spectral and spatial object properties. The most promising of them are devices based on acousto-optic tunable filters (AOTFs). They provide high spatial and spectral resolution, fast arbitrary spectral tuning (spectral agility) and capability of transfer function modulation and synthesis. For many applications, particularly for group processing of spectral images and for object detection and recognition, the quality of image transmission through AOTF is a matter of principle. One of the methods for compensation of these deformations is using two AOTFs placed in series (tandem AOTF). Till now the problem of image transmission has not solved. The only accurate investigations was aimed at single AOTF and need to be continued. The article analyzes influence of diffraction produced by a pair of phase gratings on the characteristics of image transmission. Matrix method for image deformation description in linear approximation is considered. The action of double AOTF imaging spectrometer is described by sequential application of three operators: operators BI and BII of each single AOTF and operator R of their mutual orientation. Two configurations of monochromator differing in AOTFs orientation are analyzed and compared. Formula for estimation of possible inaccuracy in filters orientation are obtained. It is shown that one of configurations can provide complete compensation of image deformation caused by each AOTF. The method is universal and may be formalized in the form of computer program.