| 摘要 |
An illumination system includes a polarization selective holographic element, which includes at least one optically anisotropic material, arranged to separate light of a first polarization type from light of a second polarization type, and converting section for converting light of at least one of the first and second polarization types to light of a common polarization type. Where the polarization selective holographic element separates two orthogonal components of plane polarized light from one another, the converting section can include a polarization rotator, for example a half wave plate, or alternatively a quarter wave plate and a reflector arranged to reflect light back through the quarter wave plate. Where the polarization selective holographic element separates opposite handed components of circularly polarized light, the converting section can include a reflector.
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