基于柔性基底的双层J型可拉伸手性太赫兹超表面

Bilayered J-Shaped Stretchable Chiral Terahertz Metasurface Based on Flexible Substrate

结构的手性在自然界中普遍存在,通常表现为不能通过平移或旋转与其镜像结构重合的现象.因为光谱探测技术能够反映光和物质相互作用产生的丰富信息,所以利用光学方法检测手性特征成为了探测和鉴别手性物质的常用手段.手性超表面能够通过人工设计达到极大的圆二色性(CD),是物质检测和传感领域的研究热点.设计了一种可动态调控CD响应,同时实现高传感性能的太赫兹手性超表面.该超表面以柔性材料为基底,前后表面为四重旋转对称的J型金属结构.仿真结果表明:该手性超表面在0.760 THz处能够产生高达0.805的强CD值;通过二维方向等比例拉伸,CD峰从0.760 THz红移至0.650 THz附近,且能保持很高的CD信号;同时,其传感灵敏度高达327 GHz/RIU,且在相对拉伸形变量高达20%的拉伸过程中仍能较好地保持手性响应和传感性能.所设计的手性超表面在动态多功能器件、可穿戴传感器领域具有潜在的应用价值.

Chirality of structure is prevalent in nature,which is usually manifest as the inability to coincide with its mirror structure by translation or rotation.Because spectrum detection techniques can reflect the abundant information of the interaction between light and matter,chiroptical spectroscopy has become a common method to investigate and identify chiral substances.Chiral metasurface can be artificially designed to achieve strong circular dichroism(CD),which is a research hot spot in the fields of matter detection and sensing.We propose a terahertz chiral metasurface that can dynamically control the CD response while achieving high sensing performance.The metasurface is based on a flexible material,and its top and bottom surfaces are J-shaped metal structures with four-fold rotational symmetry.The simulation results show that the chiral metasurface can produce a high CD value up to 0.805 at 0.760 THz.And by equally proportional stretching in two-dimensions,the CD peak redshifts from 0.760 THz to 0.650 THz maintaining a strong CD signal.Meanwhile,its sensing sensitivity can reach 327 GHz/RIU,and its chiral response and sensing performance are well maintained during the stretching process with the relative stretching deformation up to 20%.The designed chiral metasurface has potential applications in the field of dynamic multifunctional devices and wearable sensors.