| 摘要 |
A method and an apparatus provide an optical switching system (100) which maintains essentially constant transmissivity at its maximum value and develops independent of viewing angle two system optical transmission states of substantially contaminant-free light. The system includes first and second light gates (102 and 104) of which each has associated therewith contaminant light intensity patterns (48 and 66) with points of local maxima (54, 56, 58, 60, 68, and 70) and local minima (62 and 72) in two system optical transmission states. Quarter-wave plates (134 and 136) are positioned between the light gates to develop circular polarization of light propagating between them. The presence of circularly polarized light maintains the system transmissivity at its maximum value while the relative orientation of the light gates is changed to align their contaminant light intensity patterns to block the transmission of contaminant light, and thereby improve the viewing angle performance.
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