Tang Chaodong, Chen Feiliang, Du Jinglei, Hou Yidong
College of Physics, Sichuan University, Chengdu, Sichuan 610065, China.
Nanoscale. 2020 Apr 30;12(16):9162-9170. doi: 10.1039/d0nr01928c.
Large-area and high-performance chiral metamaterials are highly desired for practical applications, such as controlling the polarization state of an electromagnetic wave and enhancing the sensor sensitivity of chiral molecules. In this work, cavity-enhanced chiral metamaterials (CECMs) with a large area (1 cm2) have been fabricated by the convenient angle-dependent material deposition technique. The optimal chiral signal (g factor) resonance in the visible waveband can reach about 0.94 with a figure of merit (FOM) of about 5.2, which is about ten times larger than that of chiral metamaterials (CMs) without a cavity (i.e., a g factor of 0.094 with the FOM of about 1.12). Both the theoretical and experimental results demonstrate that the circular conversion components from the anisotropic geometry of CMs play a crucial role in the final chiroptical effect of CECM, which together with the cavity effect enhance both the chiroptical resonance intensity and FOM. Choosing the appropriate deposition parameters can effectively modify the geometric anisotropy of CM and thus the chiroptical effect of CECM. The geometric nanoscale morphology, electromagnetic properties and sensor performance were investigated carefully in this work. The fabricated CECM working in the visible waveband together with the cavity-enhanced scheme provides a competitive candidate for enhancing the performance and the practical applications of CMs.
大面积且高性能的手性超材料对于实际应用来说是非常需要的，例如控制电磁波的偏振态以及提高手性分子的传感器灵敏度。在这项工作中，通过便捷的角度相关材料沉积技术制备了大面积（1平方厘米）的腔增强手性超材料（CECM）。在可见光波段，最优的手性信号（g因子）共振可达约0.94，品质因数（FOM）约为5.2，这比没有腔的手性超材料（CM）大大约十倍（即g因子为0.094，FOM约为1.12）。理论和实验结果均表明，来自CM各向异性几何结构的圆转换分量在CECM的最终旋光效应中起关键作用，其与腔效应一起增强了旋光共振强度和FOM。选择合适的沉积参数可以有效地改变CM的几何各向异性，从而改变CECM的旋光效应。在这项工作中，对几何纳米级形态、电磁特性和传感器性能进行了仔细研究。在可见光波段工作的制备好的CECM以及腔增强方案为提高CM的性能和实际应用提供了一个有竞争力的候选方案。
