SPECTRAL FUNCTION SHAPING TECHNIQUE FOR WIDE-APERTURE ACOUSTO-OPTICAL TUNABLE FILTERS
V. E. Pozhar1, E. A. Dyakonov2
1Scientific and Technological Center of Unique Instrumentation, Russian Academy of Sciences, Moscow, Russia
2Lomonosov Moscow State University, Physics Department, Moscow, Russia
Keywords: acousto-optical tunable filter (AOTF), light diffraction by ultrasound, optical spectral systems, spectral transmission, real-time optical systems
Abstract
The development of acousto-optical tunable filter with a synthesized spectral transmission characteristic is presented. The wide-aperture (wide-angle, tangent) geometry of acousto-optical tunable filters widely used in modern hyperspectral systems is considered. It is shown that they can be described with a single-coordinate model of acousto-optic interaction. The relationships between the driving radiofrequency signal characteristics, the parameters of the acoustic wave forming the grating, and the spectral transmission function of the acousto-optical filter are determined. The fundamental limitations on the spectral transmission function characteristics are revealed. In a linear transmission approximation, the deduced relations describe the operation of an acousto-optical filter with an arbitrary law of amplitude and frequency modulation of the driving signal. The results are applicable for development of acousto-optical spectral systems with a controlled transmission function.
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