Patent attributes
A phase difference detector generates a plurality of signals from an input beam including orthogonal, linearly polarized object and reference beam components. The detector may be configured such that as the reference and object beam components traverse the detector, phase shifts due to surface interactions are made as similar as possible between the s-components of the reference object beams, and between the p-components of the reference and object beams. Various outputs may be formed by interfering p-components exclusively, or s-components exclusively, negating errors that may otherwise arise due to differential phase shifts between p- and s-components. Phase-shifting elements in the detector may receive beams from beam splitting surfaces where the transmissive differential phase shift between p- and s-components is adjusted to insignificance.
