Acousto-optical tunable filter for a swept light source with variable transmission function

Spectrally tunable illumination is widely used for colorimetry, spectroscopy, spectral-domain optical coherence tomography and other applications. Most of the swept light sources suffer either from a limited number of spectral channels or from spatial noise and speckles. In this paper, we discuss an approach based on acousto-optic filtration of wide-band illumination. We show experimentally that acousto-optical tunable filter (AOTF) provides a unique collection of features: arbitrary spectral tuning, multi-bandpass mode and acoustic frequency modulation. Results of multiple experiments show that the proposed technique may become the basis of the swept light sources with arbitrarily specified number, positions and width of the spectral channels.