Circularly polarized emission from a narrow bandwidth dye doped into a chiral nematic liquid crystal

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Abstract
We report on circularly polarized light emitted from a chiral nematic liquid crystal doped with a luminescent organolanthanide dye. The organolanthanide emission displays an extremely narrow spectral bandwidth of Δ λE≈ 8 nm. This is considerably narrower than the CNLC selective reflection bandwidth Δ λR≈60 nm. When conventional dyes with broader emission bandwidths are dissolved into CNLCs, the average degree of circular polarization g of emitted light is reduced from the maximum degree g MAX ; this is due to the overlap of the emission band with the reflection band edges, and spectral regions outside the reflection band. Here, however, we can place the entire emission band inside the reflection band and achieve g ≈ g MAX=1.27. Furthermore, a high degree of circular polarization is maintained under off-axis viewing up to a viewing angle of ≈ 30° to the normal.