| 摘要 |
The circular dichroism exhibited by cholesteric liquid materials is employed to couple light having selected determinable wavelength and circular polarization out of an optical path. Thin films of selected cholesteric liquid crystal materials are interposed in an optical path so that the circular dichroism of the liquid crystal materials causes scattering of light energy having a particular combination of wavelength and circular polarization which is characteristic of the properties of each such material. Light energy which is not within the affected wavelength and circular polarization combinations is transmitted along the optical path without significant attenuation. The scattered light is coupled out of the optical path where it may be suitably detected for signal information content. The coupler may be rendered tunable by impressing an electric field across the cholesteric liquid crystal material to change the helical pitch of its molecular alignment, causing a commensurate change in the wavelength of light energy which will be scattered.
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