ABSTRACT

We report complex optical investigations of polymer-stabilised cholesteric photonic liquid crystal doped by a dichroic fluorescent dye. For the first time, we employed a combination of various experimental methods, including measurements of spectra of transmission, reflection, rotation of the plane of polarisation of light, fluorescence, to characterise the properties of the photonic crystal. The peculiarity of the reported investigations is employing a photosensitive cholesteric mixture forming the photonic crystal. The position of the photonic band could be changed by illumination with ultraviolet light and stabilised by thermopolymerisation. In this way, the position of the cholesteric band was matched with the emission band of the fluorescent dye, which enabled to perform diversified studies on the same photonic crystal. We determined the parameters, which defined the optical properties of the photonic crystal, spectral dependence of the transformation of linearly polarised light to elliptically polarised as the light passes the photonic crystal, the photonic density of states. The interpretation of the experimental data was performed using analytical expressions obtained from the solution of Maxwell’s equations, numerical calculations by the Berreman matrix method.

摘要

我们报告了由二向色荧光染料掺杂的聚合物稳定胆甾型光子液晶的复杂光学研究。我们第一次结合了各种实验方法，包括测量透射光谱、反射光谱、光偏振平面的旋转、荧光，来表征光子晶体的特性。报告研究的特点是采用光敏胆甾醇混合物形成光子晶体。光子带的位置可以通过紫外线照射来改变，并通过热聚合来稳定。通过这种方式，胆甾带的位置与荧光染料的发射带相匹配，从而能够对同一光子晶体进行多样化的研究。我们确定了参数，这些参数定义了光子晶体的光学特性、线性偏振光到椭圆偏振光通过光子晶体时的光谱依赖性、光子态密度。实验数据的解释是使用从麦克斯韦方程组的解中获得的解析表达式，通过 Berreman 矩阵方法的数值计算进行的。