Second-Harmonic Generation Optical Rotation Solely Attributable to Chirality in Plasmonic Metasurfaces.
Second-Harmonic Generation Optical Rotation Solely Attributable to Chirality in Plasmonic Metasurfaces.
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DOI：
10.1021/acsnano.8b00601
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发表时间：
2018-05
期刊：
影响因子：
17.1
通讯作者：
J. Collins;D. Hooper;A. Mark;Christian W. Kuppe;V. Valev
中科院分区：
文献类型：
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作者：
J. Collins;D. Hooper;A. Mark;Christian W. Kuppe;V. Valev
手性等离子体纳米结构（缺乏镜像对称性的那些）可以被设计成操纵入射光的偏振，从而产生手性（手性光学）效应，例如圆二色性（CD）和旋光（OR）。由于高对称敏感性，二次谐波产生（SHG-CD和SHG-OR）中的相应效应通常相比之下强得多。这些非线性效应长期以来一直用于手性分子的分析和表征;然而，如果结构由于各向异性而具有双折射性，则即使在非手性结构中也可以发生线性和非线性光学旋转。重要的是，由各向异性引起的手旋光效应通常表现出对结构取向的强烈依赖性。在这里，我们报告了一个大的二次谐波产生的±45°的旋光，由于在一个高度各向异性的螺旋超材料的固有手性。的SHG强度被发现强烈相关的结构各向异性，但是，SHG-OR的角度是不变的样品旋转。我们表明，通过调整各向异性纳米结构的几何形状，各向异性，手性和实验几何形状之间的相互作用，可以允许更大的控制等离子体超材料的手性光学特性。
Chiral plasmonic nanostructures, those lacking mirror symmetry, can be designed to manipulate the polarization of incident light resulting in chiroptical (chiral optical) effects such as circular dichroism (CD) and optical rotation (OR). Due to high symmetry sensitivity, corresponding effects in second-harmonic generation (SHG-CD and SHG-OR) are typically much stronger in comparison. These nonlinear effects have long been used for chiral molecular analysis and characterization; however both linear and nonlinear optical rotation can occur even in achiral structures, if the structure is birefringent due to anisotropy. Crucially, chiroptical effects resulting from anisotropy typically exhibit a strong dependence on structural orientation. Here we report a large second-harmonic generation optical rotation of ±45°, due to intrinsic chirality in a highly anisotropic helical metamaterial. The SHG intensity is found to strongly relate to the structural anisotropy; however, the angle of SHG-OR is invariant under sample rotation. We show that by tuning the geometry of anisotropic nanostructures, the interaction between anisotropy, chirality, and experimental geometry can allow even greater control over the chiroptical properties of plasmonic metamaterials.