Zhou Shaoen, Lai Pengtao, Dong Guohua, Li Ping, Li Yuxiang, Zhu Zheng, Guan Chunying, Shi Jinhui
Opt Express. 2019 May 27;27(11):15359-15367. doi: 10.1364/OE.27.015359.
We numerically investigate a tunable and extrinsic chiroptical response of a graphene achiral metamaterial in mid-infrared regime. The achiral metamaterial is composed of cascaded metallic split ring apertures and complementary graphene rings patterned on a dielectric layer. The strong extrinsic chiroptical responses of the metamaterial are allowed at oblique incidence and the integrated graphene can dynamically modulate extrinsic chirality by changing its Fermi level. The spectra of the chiroptical responses will show a blue shift with increasing the Fermi level of the patterned graphene. The maximal values of circular dichroism in the reflection and transmission modes can reach 80% and 50%, respectively. The maximal values of polarization rotation angle in the reflection and transmission modes can reach 80° and 60°, respectively. This graphene-based metamaterial design paves a way for a myriad of important terahertz (THz) and mid-infrared applications, such as optical modulators, absorbers and polarizers.
我们对石墨烯非手性超材料在中红外波段的可调谐且非本征的旋光响应进行了数值研究。该非手性超材料由级联金属裂环孔径和图案化在介电层上的互补石墨烯环组成。超材料的强非本征旋光响应在斜入射时出现，且集成的石墨烯可通过改变其费米能级来动态调制非本征手性。旋光响应光谱将随着图案化石墨烯费米能级的增加而出现蓝移。反射和透射模式下圆二色性的最大值分别可达80%和50%。反射和透射模式下偏振旋转角的最大值分别可达80°和60°。这种基于石墨烯的超材料设计为众多重要的太赫兹（THz）和中红外应用，如光调制器、吸收器和偏振器，铺平了道路。
