摘要 |
The present invention deals with an optical transmission filter for effecting differential phase delay upon light in a beam polarized in a P dimension, as a function of position within the filter aperture. The filter employs two lenses of birefringent material, the crystal optic axes of the respective lens materials being oriented in mutually orthogonal positions and at a 45 DEG angle to the P dimension. The lenses have their adjacent surfaces respectively concave and convex with the same radius of curvature and their non-adjacent surfaces flat. The phase response of the filter is a function of the radial distance of a beam element from the filter axis with spherical lenses and a function of a linear coordinate distance from the filter axis with cylindrical lenses. A two-part construction for one lens, which permits adjustment of the difference in center thicknesses between the two lenses, allows adjustment of the differential phase delay with respect to a spacial reference.
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