Imaging drift of acousto-optic modulator spectral camera

The image drift phenomenon caused by the dispersion of an acousto-optic crystal is researched when the spectral camera is imaging based on acousto-optic tunable filtering mechanism.The image drift caused by the crystal outside diffraction angle is calculated theoretically and measured experimentally by the dispersion compensation and the image displacement compensation methods when a Acousto-optic Tunable Filter(AOTF) is in the visible band of 488-644 nm,and the experiments are also optimized and analyzed.Using the dispersion compensation method and in the incident light wavelength of 488-644 nm,when we adjust the incident subject as a parallel light and add a wedge of 0.6° in the crystal exit surface,the change of the crystal outside diffraction angle can be reduced from 0.066 50° to 0.004 2°,and the image drift is reduced from 162.1 μm to 10.9 μm.Using the image displacement compensation method without adding the optical wedge,when the incident light wavelength is in 488-644 nm,the image level drift can be reduced from 468 μm to 0.658 μm within a pixel drift.Experimental results show that the effect of the imaging can be neglected,and the two methods can improve the imaging resolution of the AOTF based on mechanism of the spectral camera.