Because of the presence of a selective reflection band, cholesteric liquid crystals strongly modify the emission of fluorescent guest molecules. While emission along the helical axis is well understood, the emission properties at oblique angles with respect to the cholesteric helix have so far not been explored in detail. We present a systematic study of the angular-dependent spontaneous emission properties of dye-doped cholesteric films, including a full Stokes analysis of the emitted light. Variation of the cholesteric pitch allows us to probe the effect of the photonic band structure on spontaneous emission in a wide angular range. We find exceptional angular-dependent intensity and polarization variations of the emitted light and give experimental proof for the splitting of the first-order reflection band as well as its overlap with the second-order band at large detection angles.

中文翻译：

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胆甾醇型液晶薄膜的角度相关自发发射

由于存在选择性反射带，胆甾型液晶极大地改变了荧光客体分子的发射。尽管沿螺旋轴的发射是众所周知的，但相对于胆甾型螺旋的倾斜角的发射特性迄今尚未得到详细研究。我们目前对染料掺杂的胆甾型薄膜的角度依赖性自发发射特性的系统研究，包括对发射光的完整斯托克斯分析。胆甾型节距的变化使我们能够在宽角度范围内探究光子能带结构对自发发射的影响。