Electronically tunable acousto-optic filter

The paper reports experimental results on a new type of electronically tunable optical filter (1). The filter makes use of collinear acoustic-optic diffraction in an optically anisotropic media. By changing the driving acoustic frequency, the band of optical frequencies which the filter will pass may be changed. A LiNbO
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acoustic-optic filter with a pass band approximately 2 Å wide, which is tunable from 750 Å to 5500 Å by changing the acoustic frequency from 750 Mc to 1050 Mc, has been demonstrated. Peak transmission at band center is about 30 percent and average rejection outside the pass band is about 50 db.