| 摘要 |
A wavelength discriminating optical filter has birefringent retarders stacked between polarizing filters, in relative rotational orientations causing passband wavelengths to emerge in a polarization state aligned to a second such polarizing filter, for transmission, whereas wavelengths at orthogonal polarization states are blocked. The second polarizing filter can be a wiregrid type that reflects the blocked orthogonal component backwards along the light signal propagation path. Internal reflections are minimized while obtaining a high transmission ratio and high discrimination for the passband wavelengths, by pairing a zero-degree reflective polarizer as the second or selection polarizer, with a preceding non-zero-degree reflective polarizer. The non-zero-degree reflective polarizer can absorb the blocked orthogonal polarization components, for example using an oriented dichroic material, or a polarizing cube or the like can be provided to divert the blocked polarization component.
|
