The circular Bragg phenomenon
The circular Bragg phenomenon
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DOI：
10.1364/aop.6.000225
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发表时间：
2014-06-01
影响因子：
27.1
通讯作者：
Lakhtakia, Akhlesh
中科院分区：
文献类型：
--
作者：
Faryad, Muhammad;Lakhtakia, Akhlesh
结构手性材料，如Reusch桩，液晶（CLC），和手性雕塑薄膜（STFs），由于其沿着固定轴的螺旋非均匀性，表现出的圆布拉格现象是几乎全反射的入射光的共手圆偏振态，但很少反射的交叉手圆偏振态的入射光。表现在取决于入射角，结构周期和相对介电常数并矢的光谱制度，该现象相当于形成一个光管，在适当的条件下向后泄漏能量。温和的耗散和色散不会显着影响圆形布拉格制度。每一种足够厚度的结构手性材料本质上都是一种圆偏振敏感带阻滤波器。具有或不具有结构缺陷的这些材料的级联可以用于满足复杂的滤波要求，例如多频带、窄带和超窄带滤波。由于流体对手性STF的渗透导致的圆形布拉格状态的偏移使得能够进行光学感测。圆偏振光源可以通过将发射源嵌入CLC和手性STF中来制造。(C)2014年美国光学学会
Exhibited by structurally chiral materials-such as Reusch piles, cholesteric liquid crystals (CLCs), and chiral sculptured thin films (STFs)-due to their helical nonhomogeneity along a fixed axis, the circular Bragg phenomenon is the almost total reflection of the incident light of the co-handed circular-polarization state but very little reflection of the incident light of the cross-handed circular-polarization state. Manifesting itself in spectral regimes that depend on the angle of incidence, the structural period, and the relative permittivity dyadic, the phenomenon amounts to the formation of a light pipe that bleeds energy backward under appropriate conditions. Mild dissipation and dispersion do not significantly affect the circular Bragg regime. Every structurally chiral material of sufficient thickness is essentially a circular-polarization-sensitive band-rejection filter. Cascades of these materials with or without structural defects can be used to satisfy complex filtering requirements, such as multiband, narrowband, and ultra-narrowband filtering. A shift in the circular Bragg regime due to infiltration of a chiral STF by a fluid enables optical sensing. Sources of circularly polarized light can be fabricated by embedding emission sources in CLCs and chiral STFs. (C) 2014 Optical Society of America