Wang Yongkai, Wen Xiaojing, Qu Yu, Wang Li, Wan Rengang, Zhang Zhongyue
Opt Express. 2016 Jul 25;24(15):16425-33. doi: 10.1364/OE.24.016425.
Circular dichroism (CD) and asymmetric transmission (AT) are important in the field of negative refractive index media and perfect polarization converters. A large difference between T and T in the transmission matrix T leads to a large CD effect, whereas a large difference between T and T leads to a large AT effect. To achieve large CD and AT effects simultaneously, we theoretically analyzed the transmission matrix T and proposed the chiral plasmonic nanostructure of twist nanoslit-nanorod arrays (TNNAs) in this study. Results calculated by the finite element method show that, at around resonant wavelengths, the spectra of T and T correspondingly present peaks and valleys leading to a large CD effect. Meanwhile one of the spectra for T and T presents valleys and another presents peaks leading to a large AT effect. More importantly, the magnitude of CD is equivalent to that of AT. In addition, the CD and AT effects strongly depend on the geometric parameters of TNNAs. Overall, these results are useful for designing chiral plasmonic nanostructures with large CD and AT effects.
圆二色性（CD）和不对称传输（AT）在负折射率介质和完美偏振转换器领域具有重要意义。传输矩阵T中T与T之间的巨大差异会导致较大的CD效应，而T与T之间的巨大差异会导致较大的AT效应。为了同时实现大的CD和AT效应，我们在本研究中对传输矩阵T进行了理论分析，并提出了扭曲纳米狭缝-纳米棒阵列（TNNAs）的手性等离子体纳米结构。有限元法计算结果表明，在共振波长附近，T和T的光谱相应地呈现出峰和谷，从而导致较大的CD效应。同时，T和T的光谱之一呈现谷，另一个呈现峰，从而导致较大的AT效应。更重要的是，CD的大小与AT的大小相当。此外，CD和AT效应强烈依赖于TNNAs的几何参数。总体而言，这些结果对于设计具有大CD和AT效应的手性等离子体纳米结构很有用。
