| 摘要 |
<p>A birefringent crystal is provided for an electronically tunable acousto-optic filter wherein a light beam is diffracted by a collinear acoustic wave in the birefringent crystal from a first polarization into an orthogonal polarization, the crystal orientation being such that the effect due to birefringence changes is balanced by the effect due to acoustic anisotropy, providing a filter with high resolution and large optical apertures. For a filter employing a quartz crystal, a crystal cut is utilized wherein the longitudinal axis of the filter medium lies along a crystal orientation of approximately (zyw) - 11.2 DEG ; for a lithium niobate crystal, the cut is (zyw) 4.0 DEG .</p> |
